Today’s long haul and metro high-speed networks are mainly based on synchronous digital hierarchy (SDH) or its American equivalent synchronous optical network (SONET) and wavelength division multiplex (WDM). On the other hand, the large amount of traffic growth during the last years has been caused mainly by Internet protocol (IP) traffic. Traditionally, the IP-router based networks and the cro...

Digital VLSI circuits are usually classi ed into synchronous and asynchronous circuits Synchronous circuits are generally controlled by global synchronization signals provided by a clock Asynchronous circuits on the other hand do not use such global synchroniza tion signals Between these extremes there are various hybrids Digital circuits in today s commercial products are almost exclusively sy...

We conduct a complexity-theoretic study of focussed proof systems, relating the alternation of synchronous and asynchronous phases in a proof to an appropriate alternating time hierarchy, for instance the polynomial hierarchy. We propose a notion of ‘over-focussing’ that admits non-branching invertible rules during synchronous phases, due to the fact that deterministic computations can equally ...

We present a scheme that achieves self-stabilizing Byzantine digital clock synchronization assuming a “synchronous” system. This synchronous system is established by the assumption of a common external “beat” delivered with a regularity in the order of the network message delay, thus enabling the nodes to execute in lock-step. The system can be subjected to severe transient failures with a perm...

This paper investigates specification and verification of synchronous circuits using DILL (Digital Logic in LOTOS). After an overview of the DILL approach, the paper focuses on the characteristics of synchronous circuits. A more constrained model is presented for specifying digital components and verifying them. Two standard benchmark circuits are specified using this new model, and analysed by...

The provision of broad-band services based on either the Internet or the asynchronous transfer mode (ATM) technique requires a new generation of access networks. In the short term, solutions such as x-digital subscriber line (DSL) and hybrid fiber coaxial (HFC), allowing the reuse of existing infrastructures, look very promising. For the longer term, new infrastructures based either on radio or...

The digital resources construction of college library is important for the development of college, therefore it is necessary to evaluate it base on an effective evaluation method, and the application of fuzzy analytic hierarchy process on it is studied in depth. Firstly, the meaning of performance evaluation of digital construction of college library is discussed; Secondly, the digital resource...

The rapid growth of bandwidth requirements for services like IP television and video on demand over Internet together with high speed Internet access have demand for very high bandwidth to customers as well as the changing role of enterprise networking are causing disruptive change in the enterprise local area networks. The most suitable solution for satisfying the high bandwidth demand with a ...

Recent advances in optical ber systems and transmission equipments play a primary role in today's telecommunications networks. The standardized SDH (Synchronous Digital Hierarchy) technology made the rings the most survivable architecture for designing high speed networks. Designing such networks involves not only the connguration of rings at the logical level but also the mapping of such conng...

| The SDH (Synchronous Digital Hierarchy) architecture is one of the underlying technologies used by ATM networks. The SDH includes various protection mechanisms. One main design issue is probably the reconnguration process in case of failure. In case of SDH works on optical bres with a ring network topology, the Automatic Protection Switching (APS) protocol can be used. This paper addresses th...