Formulas relating stability estimates of discrete-time and sampled-data nonlinear systems

We provide an explicit stability or input-to-state stability (ISS) estimate for a sampled-data nonlinear system in terms of the estimate for the corresponding discrete-time system and a function describing inter-sample growth. It is quite obvious that a uniform inter-sample growth condition, plus an ISS property for the exact discrete-time model of a closed-loop system, implies uniform ISS of the sampled-data nonlinear system. Our results serve to quantify these facts by means of comparison functions. Our results can be used as an alternative to prove and extend results in [[Reference to 1]] or extend some results in [[Reference to 4]] to a class of nonlinear systems. Finally, the formulas we establish can be used as a tool for some other problems which we indicate.     

会计科目的设置与电子报表的编制

随着会计电算化的普及推广。财务软件的二次开发成为迫切需要解决的问题之一，文章从实践的角度出发，讨论了财务软件中电子报表的编制与会计科目的设置之问的关系。通过对会计科目设置的修改，修正目前通用财务软件中电子报表生成时存在的一些漏洞，使之更符合企业实际。     

论高校学生职业道德的“势”与“导”

改革开放以来，新旧体制的交替和新旧矛盾的冲突，高校学生职业价值观念出现颠倒错位、职业价值取向出现市侩庸俗、职业道德评判出现含混模糊、职业道德心理出现严重失衡等令人担忧的问题。正视高校学生职业道德的客观现实并因势利导，不断强化其职业道德教育，必将成为时代赋予思想政治工作者的全新课题。     

I — an interactive program for calibrating activated sludge systems

I — an interactive program for calibrating activated sludge systems is formulated and demonstrated. The model involves a heuristic screening algorithm for exploring the system equations structure, analytical computations of the sensitivities of the variables to the model coefficients, analytical computations of the gradients of the objective functions selected for the calibration process, and a gradient interactive steepest descent minimization scheme. The methodology was implemented in an end-user PC program: I , that uses the TK S ® and M ® as computational engines, and as the shell. Applications to the activated sludge system models of (Argaman Water Research 29(1) and Argaman et al. (Journal of Environmental Engineering ASCE 125(7) (1999), 608-617) are presented.     

浅谈我国环境保护标准化工作现状及发展

本文从当前我国环境保护形势出发,概括说明我国环境保护标准工作现状,一方面介绍了我国的环境保护标准体系,另一方面分析了我国环境保护标准工作存在的问题,最后,归纳了我国政府环保部门近几年标准化工作的新进展。     

谈文献检索课改革的完善与深化

本文首先分析了文献检索课目前所处地位及面临的改革要求,根据国家教委的有关精神,提出文献检索课改革应进一步完善与深化,并就课程名称的与规范、教学内容的调整与扩充、以及教学保证体系的建立与完善等等方面提出建议。     

Isolation concepts for efficiently enumerating dense subgraphs

In an undirected graph G=(V,E), a set of k vertices is called c-isolated if it has less than ck outgoing edges. Ito and Iwama [H. Ito, K. Iwama, Enumeration of isolated cliques and pseudo-cliques, ACM Transactions on Algorithms (2008) (in press)] gave an algorithm to enumerate all c-isolated maximal cliques in O(4^cc⁴|E|) time. We extend this to enumerating all maximal c-isolated cliques (which are a superset) and improve the running time bound to O(2.89^cc²|E|), using modifications which also facilitate parallelizing the enumeration. Moreover, we introduce a more restricted and a more general isolation concept and show that both lead to faster enumeration algorithms. Finally, we extend our considerations to s-plexes (a relaxation of the clique notion), providing a W[1]-hardness result when the size of the s-plex is the parameter and a fixed-parameter algorithm for enumerating isolated s-plexes when the parameter describes the degree of isolation.     

Exponential stability of singular systems with multiple time-varying delays

This paper deals with the class of continuous-time singular linear systems with multiple time-varying delays in a range. The global exponential stability problem of this class of systems is addressed. Delay-range-dependent sufficient conditions such that the system is regular, impulse-free and α-stable are developed in the linear matrix inequality (LMI) setting. Moreover, an estimate of the convergence rate of such stable systems is presented. A numerical example is employed to show the usefulness of the proposed results.     

A distributed controller approach for delay-independent stability of networked control systems

This article introduces a novel distributed controller approach for networked control systems (NCS) to achieve finite gain L₂ stability independent of constant time delay. The proposed approach represents a generalization of the well-known scattering transformation which applies for passive systems only. The main results of this article are (a) a sufficient stability condition for general multi-input-multi-output (MIMO) input-feedforward-output-feedback-passive (IF-OFP) nonlinear systems and (b) a necessary and sufficient stability condition for linear time-invariant (LTI) single-input-single-output (SISO) systems. The performance advantages of the proposed approach are reduced sensitivity to time delay and improved steady state error compared to alternative known delay-independent small gain type approaches. Simulations validate the proposed approach.     

A vertex-first parametric algorithm for polyhedron blending

This paper enhances the conventional parametric algorithms for polyhedron blending, by strategically inverting the edges-first approach to vertex-first, so that matching the vertex blending surface (using a triangular or tensor product Bézier surface, or an S-patch) with the edge blending surfaces (generated by Hartmann method) becomes essentially easier. Based on a study of cross boundary derivatives (those of S-patches are deduced herein), G^g-continuity between all the above surfaces and the primary planar faces is achieved by a novel trick as a first step: assigning the vertex, some edge points and some face points to be the proper control points. This still leaves enough free parameters usable for changing the blending configuration. The new algorithm is illustrated with two practical examples involving miscellaneous vertices up to 6-edge convex–concave.