一种适用的智能电话集线器

为增加ＪＫ－１０００微波通信系统的话务量，详细介绍了一种以ＴＭ８８１６为开关器件的电话集线器的硬件构成和软件框图，实验已证明这种集线器是可用的。     

阴影对GMSK卫星移动通信系统性能的影响

导出了采用L重最大比组合（MRC）和差分相位检测（DPD）方案的高斯最小频移键控（GMSK）卫星移动通信系统在不同信道条件下的误比特率公式，并利用实测数据给出数值计算结果。可用于分析阴影特性对卫星移动信道性能的影响并指导系统设计。     

一种基于H.263+的双正交小波视频编码技术

在分析了双正交小波特点的基础上，提出了基于Ｈ．２６３＋的双正交小波视频编码方案，并用实验证明了此项技术的可行性与有效性。     

Studies of Adsorption Kinetics and Defects of Self‐Assembled Thiol Monolayers on Gold by Capacitance Plane Plot

The capacitive property of an electrode/electrolyte interface can be described by complex capacitance. The capacitance plane plots (CPPs) of ideal polarized and kinetic controlled electrodes are derived based on the concept of complex capacitance. By using CPPs, the capacitance of electrode/electrolyte interface can be conveniently determined. In this work, CPPs obtained in ac impedance experiments are employed for the first time in studying the kinetics of adsorption process of the thiol monolayer. The coverage of octadecanethiol (ODT) monolayer on gold is examined as a function of adsorption time. The adsorption process of ODT molecules on gold exhibits two distinct phases: an initial rapid step followed by a slow one. The simple Langmuir model best explains our experimental data in the initial adsorption stage. CPPs and cyclic voltammetry (CV) indicate that, in the initial adsorption step, the ODT monolayer contains defects whose number decreases with the increasing of adsorption time.     

Intersections of smooth polar unitals with secants are homeomorphic to spheres

In [5] and [6] we proved that (non-empty) sets of absolute points of smooth polarities, i.e. smooth polar unitals, in smooth projective planes of dimension 2l are smooth submanifolds of the point spaces homeomorphic to spheres of dimension . In this paper we show that the intersections of smooth polar unitals with secants are homeomorphic to spheres of dimension , respectively. Furthermore we prove that the condition of connectedness in [6, Theorem 1.2] may be omitted. This means that a closed (not necessarily connected) submanifold U of the point space of a smooth projective plane is homeomorphic to a sphere provided that there exists precisely one tangent at each point of U, and each secant intersects U transversally. If U has codimension 1 in the point space then the second condition follows from the first one, and also the intersections of U with secants are homeomorphic to spheres. This result may be generalized to compact hypersurfaces in the point spaces of smooth affine planes. Received: 1 July 2008     

On regular 4-coverings and their application for lattice coverings in normed planes

It is well known that the famous covering problem of Hadwiger is completely solved only in the planar case, i.e.: any planar convex body can be covered by four smaller homothetical copies of itself. Lassak derived the smallest possible ratio of four such homothets (having equal size), using the notion of regular 4-covering. We will continue these investigations, mainly (but not only) referring to centrally symmetric convex plates. This allows to interpret and derive our results in terms of Minkowski geometry (i.e., the geometry of finite dimensional real Banach spaces). As a tool we also use the notion of quasi-perfect and perfect parallelograms of normed planes, which do not differ in the Euclidean plane. Further on, we will use Minkowskian bisectors, different orthogonality types, and further notions from the geometry of normed planes, and we will construct lattice coverings of such planes and study related Voronoi regions and gray areas. Discussing relations to the known bundle theorem, we also extend Miquel’s six-circles theorem from the Euclidean plane to all strictly convex normed planes.     

A generalization of the Discrete Isoperimetric Inequality for Piecewise Smooth Curves of Constant Geodesic Curvature

Summary The discrete isoperimetric problem is to determine the maximal area polygon with at most <InlineEquation ID=IE"1"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"2"><EquationSource Format="TEX"><![CDATA[$]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>k$ vertices and of a given perimeter. It is a classical fact that the unique optimal polygon on the Euclidean plane is the regular one. The same statement for the hyperbolic plane was proved by K\'aroly Bezdek [1] and on the sphere by L\'aszl\'o Fejes T\'oth [3]. In the present paper we extend the discrete isoperimetric inequality for ``polygons' on the three planes of constant curvature bounded by arcs of a given constant geodesic curvature.     

Geometry of phase plane and radial solutions for nonlinear elliptic equations with extremal operators

We study the existence of positive radially symmetric solutions to a class of nonlinear elliptic problems involving extremal operators and nonlinearity of exponential or polynomial type. According to the values of a parameter, we describe situations where the equation has one, finitely many, infinitely many or no solutions, by using the geometry structure of phase plane.     

Adaptive power loading with BER-constraint for OFDM systems

for optimal BER and power distributions are derived in this article. Simulation results indicate the superiority of the proposed algorithm in terms of BER performance and algorithmic complexity.     

Group-labeled light dual multinets in the projective plane

In this paper we investigate light dual multinets labeled by a finite group in the projective plane $PG(2,\mathbb{K})$ defined over a field $\mathbb{K}$. We present two classes of new examples. Moreover, under some conditions on the characteristic of $\mathbb{K}$, we classify group-labeled light dual multinets with lines of length at least 9.