VoIP [6], [19], [25]是一種快速興起的技 術,其利用 IP (Internet Protocol) [7]技術來實現 新型的電話通訊。VoIP 透過語音信號數位化 處理、壓縮編碼等讓其於網路上傳輸;然後再 解壓縮,把數位信號還原成原音,來達到通話 的目的。VoIP 將聲音從傳送端到達目的端的 基本過程是:1.聲電轉換-透過裝置將聲波變 換為電信號;2.量化取樣-將模擬電信號按照 某種取樣方式(例如:脈衝編碼調製,即 PCM) 轉換成數位信號;3.製成封包-將一定時長數 位化後的語音信號組合,隨後,按照國際電聯 (ITU-T)的標準,這些語音數據被封裝到 RTP [2], [4]封包中,接著並進一步封裝到 UDP (User Datagram Protocol) [7]封包和 IP 封包 中;4.傳輸-IP 封包在 IP 網路由傳送端傳送 到目的端;5.接收封包並做電...

This paper describes recent progress in the study of switching linear systems i.e. linear systems whose dynamics can switch among a family of possible configurations/modes. The attention is focused on those classes of switching systems governed by unknown switching sequences. For this case, we address the problem of devising suitable control actions able to stabilize the plant and regulate its ...

We analyze the peculiarities of the magnetic dynamics of MTJs with a composite free layer. The composite magnetic layer consists of two half-ellipses separated by a non-magnetic spacer. We show that the switching barrier in these MTJs becomes practically equal to the thermal stability barrier. We investigate the dependence of the switching time and thermal stability on the geometry of these MTJ...

We study computational questions related with the stability of discrete-time linear switching systems with switching sequences constrained by an automaton. We first present a decidable sufficient condition for their boundedness when the maximal exponential growth rate equals one. The condition generalizes the notion of the irreducibility of a matrix set, which is a well known sufficient conditi...

In this paper, we study the problem of stabilizing continuous-time switched linear systems with quantized output feedback. We assume that the observer and the control gain are given for each mode. Also, the plant mode is known to the controller and the quantizer. Extending the result in the nonswitched case, we develop an update rule of the quantizer to achieve asymptotic stability of the close...

ÐAll-to-all communication is one of the most dense communication patterns and occurs in many important applications in parallel computing. In this paper, we present a new all-to-all broadcast algorithm in all-port meshes and tori. The algorithm utilizes a controlled message flooding based on a novel broadcast pattern, which ensures a balanced traffic load in all dimensions in the network so tha...

Switching supervisory is the most important section of a feedback control process inMIMO hybrid systems. By choosing a non-compatible controller, system may go tounstable mode or high overshoot response. In this paper, a new method of switchingfor selecting MBC controllers is discussed. Results of the simulation show the MIMO(2-in 2-out) linear hybrid system can be switched stable and low overs...