Scattering

System-on-chip (SoC) architectures are called to be the platform for an ever increasing number of interactive applications. One of the most time- consuming tasks is to define communication interfaces between the different components through a number of scattered heterogeneous processing nodes. That is not only a complex task, but also very specific to a certain implementation, which may limit the flexibility of the system, and makes the solutions difficult to reuse. In this paper, we describe how the distributed systems paradigm can be extended to provide a unified abstraction for both hardware and software components. Moreover, based on that abstraction, we define a low-overhead system-wide communication architecture that offers communication transparency between all kinds of components. Since the architecture is highly compatible with standard distributed object software systems, it also allows seamless interaction with any other kind of external network.

We study planar waves in a circulating, draining fluid flow, which: (i) exhibit an analogue of the Aharonov–Bohm (AB) effect in Quantum Mechanics; (ii) obey a Klein–Gordon equation on an ‘effective spacetime’ which resembles the Kerr spacetime of General Relativity; and (iii) may be observed in the laboratory using gravity waves in a shallow basin. We describe a modified AB effect which depends on two dimensionless parameters, associated with the circulation α and draining β rates; we call this the ‘αβ effect’. We show that the αβ effect is inherently asymmetric even in the low-frequency limit, and that it leads to novel interference patterns which carry the signature of both rotation and absorption.

The detection of concealed weapons at a distance is a critical security issue that has been a great challenge for different imaging approaches. In this paper we discuss the use of ultrasonics in a novel way to probe for metallic and non-metallic materials under clothing. ...

When the mechanisms of fading channels were first modeled in the 1950s and 1960s, the ideas were primarily applied to over-the-horizon communications covering a wide range of frequency bands. The 3-30 MHz high-frequency (HF) band is used for ionospheric communications, and the 300 MHz-3 GHz ultra-high-frequency (UHF) and 3-30 GHz super-high-frequency (SHF) bands are used for tropospheric scatter. Although the fading effects in a mobile radio system are somewhat different than those in ionospheric and tropospheric channels, the early models are still quite useful to help characterize fading effects in mobile digital communication systems. This tutorial addresses Rayleigh fading primarily in the UHF band. That affects mobile systems such as cellular and personal communication systems (PCS). Part I of the tutorial itemizes the fundamental fading manifestations and types of degradation

The theoretical/experimental work done in the area of digital phase-locked loops (DPLL) from 1960 to 1980 is surveyed. The survey is motivated by the fact that microprocessor technology is advancing rapidly to the extent that sophisticated and flexible signal processing algorithms for communications and control can be realized in the digital domain. It is anticipated that the use of this signal processing technology will continue to expand rapidly in the development of advanced communications and tracking receivers, for example, digital modems.

Most high-speed multiple-access networks on the market, or those currently under design, operate in a limited geographical environment and are devoted either to data-only or voice-only transmission. However, challenges issued by the marketplace require the full integration of voice, data, and video in a real-time environment. This paper proposes a metropolitan area network that covers a campus environment and truly integrates voice, data, and video under a single transmission medium. Furthermore, the transmission is achieved through a single media-access schema. This paper also presents marketing issues, network requirements, and technology constraints. The proposed mediaaccess schema is also being considered by the IEEE 802.6 MAN Committee for Standardization.