Robust output-feedback stabilization of a class of nonlinear systems with the nonlinearities of varied form

1 .INTRODUCTIONThe problem of global stabilization of nonlinearsystems by output feedback has received much at-tention. Unlike in the case of linear systems ,theseparation principle generally does not hold fornonlinear systems . This is one of the reasons whythe problemis more difficult . As investigated byRef .[1] ,some extra growth conditions onthe un-measurable states of the systemare usually neces-sary for the global stabilization of nonlinear sys-tems via output feedback. For exampl…     

Exponential distribution-based genetic algorithm for solving mixed-integer bilevel programming problems

Two classes of mixed-integer nonlinear bilevel programming problems are discussed. One is that the follower＇s functions are separable with respect to the follower＇s variables, and the other is that the follower＇s functions are convex if the follower＇s variables are not restricted to integers. A genetic algorithm based on an exponential distribution is proposed for the aforementioned problems. First, for each fixed leader＇s variable x, it is proved that the optimal solution y of the follower＇s mixed-integer programming can be obtained by solving associated relaxed problems, and according to the convexity of the functions involved, a simplified branch and bound approach is given to solve the follower＇s programming for the second class of problems. Furthermore, based on an exponential distribution with a parameter λ, a new crossover operator is designed in which the best individuals are used to generate better offspring of crossover. The simulation results illustrate that the proposed algorithm is efficient and robust.     

网络上具有一般直接免疫的SIRS传染病模型分析

考虑复杂网络上具有一般直接免疫率的SIRS传染病模型。由地方病平衡点的存在性,确定了传染病的流行阈值λc,并且通过构造合适的李雅普诺夫函数证明:当λ≤λ_c时,无病平衡点全局渐近稳定;当λλ_c时,地方病平衡点全局渐近稳定。根据免疫率的分布,提出了一致性直接免疫和目标性直接免疫。结果表明,在平均免疫率相等的条件下存在免疫丧失率的临界值δ_c,当δδ_c(δδ_c)时,目标性免疫的流行阈值小于(大于)一致性免疫的流行阈值。     

Backstepping tracking control for nonlinear time-delay systems

1. INTRODUCTION The presence of time delay has a significant effect on system performance and destroys the stability of closed-loop system[1]. Therefore, the study on time-delay systems has important practical significance. Recen- tly,considerable progress has been made in this field[1~10]. According to the dependency of the designed contr-oller depends on the time delay, the control approa-ches for time-delay systems can be classified into two categories: delay-dependent[2~3,10] and dela…     

A Construction of 1-Resilient Boolean Functions with Good Cryptographic Properties

This paper proposes a general method to construct 1-resilient Boolean functions by modifying the Tu-Deng and Tang-Carlet-Tang functions. Cryptographic properties such as algebraic degree, nonlinearity and algebraic immunity are also considered. A sufficient condition of the modified functions with optimal algebraic degree in terms of the Siegenthaler bound is proposed. The authors obtain a lower bound on the nonlinearity of the Tang-Carlet-Tang functions, which is slightly better than the known result. If the authors do not break the “continuity” of the support and zero sets, the functions constructed in this paper have suboptimal algebraic immunity. Finally, four specific classes of 1-resilient Boolean functions constructed from this construction and with the mentioned good cryptographic properties are proposed. Experimental results show that there are many 1-resilient Boolean functions have higher nonlinearities than known 1-resilient functions modified by Tu-Deng and Tang-Carlet-Tang functions.     

On algebraic immunity of trace inverse functions on finite fields of characteristic two

The trace inverse functions Tr(λx~(-1)) over the finite field F_(2~n) are a class of very important Boolean functions and are used in many stream ciphers such as SFINKS,RAKAPOSHI,the simple counter stream cipher(SCSC) presented by Si W and Ding C(2012),etc.In order to evaluate the security of those ciphers in resistance to(fast) algebraic attacks,the authors need to characterize algebraic properties of Tr(λx~(-1)).However,currently only some bounds on algebraic immunity of Tr(λx~(-1)) are given in the public literature,for example,the NGG upper bound and the Bayev lower bound,etc.This paper gives the exact value of the algebraic immunity of Tr(λx~(-1)) over F_(2~n),that is,AI(Tr(λx~(-1))) =[2n~(1/2)]- 2,where n ≥ 2,A ∈ F_(2~n) and λ≠ 0,which shows that Dalai's conjecture on the algebraic immunity of Tr(λx~(-1)) is correct.What is more,the authors demonstrate some weak properties of Tr(λx~(-1)) against fast algebraic attacks.     

Guaranteed cost control for discrete-time networked control systems with random Markov delays

The guaranteed cost control for a class of uncertain discrete-time networked control systems with random delays is addressed.The sensor-to-controller (S-C) and contraller-to-actuator (C-A) random network-induced delays are modeled as two Markov chains.The focus is on the design of a two-mode-dependent guaranteed cost controller,which depends on both the current S-C delay and the most recently available C-A delay.The resulting closed-loop systems are special jump linear systems.Sufficient conditions for existence of guaranteed cost controller and an upper bound of cost function are established based on stochastic Lyapunov-Krasovakii functions and linear matrix inequality (LMI) approach.A simulation example illustrates the effectiveness of the proposed method.     

不确定非线性系统的鲁棒自适应跟踪简化算法

传统的Backstepping自适应控制方法需要对虚拟控制律进行求导,从而导致“计算复杂性膨胀”。动态平面控制技术能够克服这一缺陷。将这一技术扩展到一类具有参数严格反馈形式的不确定非线性系统输出跟踪,这类系统同时包含线性参数和未知非线性函数两种不确定性。所设计的控制算法比现有算法大大简化,解决了“计算复杂性膨胀”问题;运用Lyapunov理论证明了闭环系统一致最终有界,仿真结果表明了算法的有效性。     

A Combinatorial Condition and Boolean Functions with Optimal Algebraic Immunity

This paper first proposes an infinite class of 2k-variable Boolean functions with high nonlinearity and high algebraic degree. Then an infinite class of balanced Boolean functions are proposed by modifying the above Boolean functions. This class of balanced Boolean functions have optimal algebraic degree and high nonlinearity. Both classes have optimal algebraic immunity based on a general combinatorial conjecture.     

Effective lower bounds of wrap-around <Emphasis Type="Italic">L</Emphasis><Subscript>2</Subscript>-discrepancy on three-level combined designs

How to obtain an effective design is a major concern of scientific research. This topic always involves high-dimensional inputs with limited resources. The foldover is a quick and useful technique in construction of fractional designs, which typically releases aliased factors or interactions. This paper takes the wrap-around L₂-discrepancy as the optimality measure to assess the optimal three-level combined designs. New and efficient analytical expressions and lower bounds of the wraparound L₂-discrepancy for three-level combined designs are obtained. The new lower bound is useful and sharper than the existing lower bound. Using the new analytical expression and lower bound as the benchmarks, the authors may implement an effective algorithm for constructing optimal three-level combined designs.     

基于单纯形剖分确定非线性比式和问题全局解的新方法

针对经济与金融中出现的一类特殊非线性比式和问题,给出一种基于单纯形剖分的全局优化算法. 在算法中, 通过构造初始单纯形, 以及使用凸包络理论, 提出了一个确定原问题最优值下界的新方法. 在确定下界的同时, 将会得到原问题的n+1可行解, 这些可行解可以用于上界的改善. 理论上证明了算法的收敛性, 数值算例表明算法是有效可行的.     

Polynomial dynamic programming algorithms for lot sizing models with bounded inventory and stockout and/or backlogging

This paper addresses a dynamic lot sizing problem with bounded inventory and stockout where both no backlogging and backlogging allowed cases are considered. The stockout option means that there is outsourcing in a period only when the inventory level at that period is non-positive. The production capacity is unlimited and production cost functions are linear but with fixed charges. The problem is that of satisfying all demands in the planning horizon at minimal total cost. We show that the no backlogging case can be solved in ) O(T ²) time with general concave inventory holding and outsourcing cost functions where T is the length of the planning horizon. The complexity can be reduced to O(T) when the inventory holding cost functions are also linear and have some realistic properties, even if the outsourcing cost functions remain general concave functions. When the inventory holding and outsourcing cost functions are linear, the backlogging case can be solved in O(T ³logT) time whether the outsourcing level at each period is bounded by the sum of the demand of that period and backlogging level from previous periods, or only by the demand of that period.     

A note on two classes of Boolean functions with optimal algebraic immunity

Tu and Deng proposed a class of bent functions which are of optimal algebraic immunity under the assumption of a combinatorial conjecture.In this paper,the authors compute the dual of the Tu-Deng functions and then show that they are still of optimal algebraic immunity under the assumption of the same conjecture.For another class of Boolean functions constructed by Tang,et al.which are of optimal algebraic immunity with similar forms to Tu-Deng functions,the authors show that they are not bent functions by using some basic properties of binary complete Kloosterman sums.     

ATIS作用下的混合交通行为网络与效率损失上界

考虑一个被路径诱导系统支持的交通网络,装有ATIS的出行者接受交通中心的指挥、按照系统最优的原则选择路径,没有该装置的出行者根据个人成本最小的原则择路,建立了刻画这种混合交通行为的变分不等式模型,推导了混合交通行为网络的效率损失上界,并以多项式路段成本函数为例给出了一些上界的特殊值.研究表明,效率损失上界与具体被研究的网络结构和交通需求水平有关,只有在特殊情况下,才可以得到与网络需求和网络结构无关的上界值.     

Upper and lower bounds on PMEPR in OFDM systems and application

Upper and lower bounds on peak-to-mean envelope power ratio (PMEPR) in OFDM systems are derived in this paper. The derivation results show that the upper bound on PMEPR only depends on the aperiodic autocorrelation functions of the data sequences and is quite useful for rapid elimination of sequences that have PMEPR exceeding a given threshold. According to the lower bound on PMEPR,it has a great change as N (number of subcarriers) varies only for a very small N. For a 16-subcarrier BPSK-OFDM system, a selective mapping (SLM) way to reduce PMEPR is investigated with the upper bound on PMEPR and the distribution of PMEPR for all possible message sequences is given. The analytic results show that the maximal PMEPR is about 6.5 dB which is 5.5 dB less than that in worst situation.     

Optimal p-Ary Codes from One-Weight and Two-Weight Codes over IF_p+ vIF_p

This paper is devoted to determining the structures and properties of one-Lee weight codes and two-Lee weight projective codes Ck1,k2,k3 over p IF+ v IFp with type p2k1pk2pk3. The authors introduce a distance-preserving Gray map from( IFp + v IFp)nto2np. By the Gray map, the authors construct a family of optimal one-Hamming weight p-ary linear codes from one-Lee weight codes over IFp+ v IFp, which attain the Plotkin bound and the Griesmer bound. The authors also obtain a class of optimal p-ary linear codes from two-Lee weight projective codes over IFp + vIFp, which meet the Griesmer bound.     

Hexagonal metric for linear codes over a finite field

This paper consider Hexagonal-metric codes over certain class of finite fields. The Hexagonal metric as defined by Huber is a non-trivial metric over certain classes of finite fields. Hexagonal-metric codes are applied in coded modulation scheme based on hexagonal-like signal constellations. Since the development of tight bounds for error correcting codes using new distance is a research problem, the purpose of this note is to generalize the Plotkin bound for linear codes over finite fields equipped with the Hexagonal metric. By means of a two-step method, the author presents a geometric method to construct finite signal constellations from quotient lattices associated to the rings of Eisenstein-Jacobi (EJ) integers and their prime ideals and thus naturally label the constellation points by elements of a finite field. The Plotkin bound is derived from simple computing on the geometric figure of a finite field.     

Efficient Asymmetrical Extended Designs Under Wrap-Around <Emphasis Type="Italic">L</Emphasis><Subscript>2</Subscript>-Discrepancy

The purpose of the present article is to introduce a class of mixed two- and three-level extended designs obtained by adding some new runs to an existing mixed two-and three-level design. A formulation of wrap-around L₂-discrepancy for the extended designs is developed. As a benchmark of obtaining (nearly) uniform asymmetrical extended designs, a lower bound to the wrap-around L₂-discrepancy for our proposed designs is established. Thorough numerical results are displayed, which provide further corroboration to the derived theoretical results.     

Theoretical design for a class of chaotic stream cipher based on nonlinear coupled feedback

1.INTRODUCTION Inordertoimprovethesecurityofchaosencryption system,wecaniteratethechaossystem.Themore chaossystemiterates,themorecomplexitbecomes, andthemoresecurethecorrespondingchaosencryp tionsystembecomes.Zhouetal[1]proposedaclassof chaoticsequencegeneratorinwhichthelinearseg mentnumberincreasedwiththeiterationnumberex ponentially.Withtheincreaseoftheiterationnum ber,thesecurityofthesystemincreaseswhilethe rateofencoding/decodingdecreases.Inaddition,the phase spacegraphhassomedefe…     

On-Line Scheduling on Parallel Machines to Minimize the Makespan

This paper considers two parallel machine scheduling problems,where the objectives of both problems are to minimize the makespan,and the jobs arrive over time,on two uniform machines with speeds 1 and s(s≥1),and on m identical machines,respectively.For the first problem,the authors show that the on-line LPT algorithm has a competitive ratio of(1 +5~(1/2))/2≈1.6180 and the bound is tight.Furthermore,the authors prove that the on-line LPT algorithm has the best possible competitive ratio if s≥1.8020.For the second problem,the authors present a lower bound of(15-(17)~(1/2))/8≈1.3596 on the competitive ratio of any deterministic on-line algorithm.This improves a previous result of 1.3473.