A wide area network (WAN) is a communications network utilizing devices such as telephone lines, satellite dishes, antennas, and microwaves to span a larger geographic area than can be covered by a local area network (LAN). Typically, a WAN consists of two or more LANs. A metropolitan area network, or MAN, is a term sometimes used to describe a system that falls somewhere between a WAN and LAN ...

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This paper presents a case study in the application of formal methods to the verification of communication protocols. We analyze one component block of telephone switching software developed in the SDL language at Alcatel Network Systems Romania. We use the IF toolset from VERIMAG Grenoble to build a state-transition model of the system and verify selected properties. We present the steps perfo...

Network covert channels enable a policy-breaking network communication (e.g., within botnets). Within the last years, new covert channel techniques occurred which are based on the capability of protocol switching. There are currently no means available to counter these new techniques. In this paper we present the first approach to effectively limit the bandwidth of such covert channels by intro...

We consider multi-channel networks where nodes may be equipped with heterogeneous radios, each potentially capable of operation on a limited portion of the total available spectrum. Moreover even the channels may not all be identical; they may possibly have different propagation characteristics, and may support different sets of transmission rates. Much prior research on multi-channel networks ...

This paper reports on the development of a framework for multimedia applications in the domain of tele-education. The paper focuses on the protocol design of a specific component of the framework, namely a shared whiteboard application. The relationship of this component with other components of the framework is also discussed. A salient feature of the framework is that it uses an advanced ATM-...

At the last few years, multimedia communication has been developed and improved rapidly in order to enable users to communicate between each other over the internet. Generally, multimedia communication consists of audio and video communication. However, this research concentrates on audio conferencing only. The audio translation between protocols is a very critical issue, because it solves the ...

We introduce a mechanism that provides an on/off switching capability in channel add-drop filter structures. These filters consist of two waveguides, a bus and a drop, coupled through a frequency-selective element. The switching functionality is achieved by incorporating materials with variable absorbing characteristics into the coupling element. When the variable material displays minimum abso...

This paper analyses the pattern and rate of adoption of mobile telephones by the Portuguese population. It is shown that the pattern of diffusion is S-shaped and is consistent with a logistic function, which describes a symmetrical growth process. Furthermore, it is found that about 67 percent of the population will likely adopt mobile phones, and that the levelling-off process in the diffusion...

We present a novel hybrid communication protocol that guarantees mobile users’ k-anonymity against a wide-range of adversaries by exploiting the capability of handheld devices to connect to both WiFi and cellular networks. Unlike existing anonymity schemes, we consider all parties that can intercept communications between the mobile user and a server as potential privacy threats. We formally qu...