This report presents a tutorial of fundamental array processing and beamforming theory relevant to microphone array speech processing. A microphone array consists of multiple microphones placed at different spatial locations. Built upon a knowledge of sound propagation principles, the multiple inputs can be manipulated to enhance or attenuate signals emanating from particular directions. In this way, microphone arrays provide a means of enhancing a desired signal in the presence of corrupting noise sources. Moreover, this enhancement is based purely on knowledge of the source location, and so microphone array techniques are applicable to a wide variety of noise types. Microphone arrays have great potential in practical applications of speech processing, due to their ability to provide both noise robustness and hands-free signal acquisition.
The rapid growth of the Web in the past two decades has made it the larg-
est publicly accessible data source in the world. Web mining aims to dis-
cover useful information or knowledge from Web hyperlinks, page con-
tents, and usage logs. Based on the primary kinds of data used in the
mining process, Web mining tasks can be categorized into three main
types: Web structure mining, Web content mining and Web usage mining.
Designing for Networked Communications: Strategies and Development is a book
about how we plan, use, and understand the products, dynamic social processes,
and tasks upon which depend some of the most vital innovations in the knowledge
society—social as well as technological ones. Focusing on various forms of design,
implementation, and integration of computer-mediated communication (CMC), the
book bridges the academic fields of computer science and communication stud-
ies.
Engineers are professional inventors, researchers, and developers. Education imbues each engineer
with discipline-specific knowledge. Combining the different disciplines allows engineers to solve
more complex problems.
During the past decade, many wireless communication techniques have been
developedto achievevariousgoals suchas higherdata rate,morerobustlink quality,
and higher number of users in a given bandwidth. For wireless communication
systems, depending on the availability of a feedback link, two approaches can be
considered: namely open and closed loop. Open loop communication system that
does not exploit the channel knowledge at the transmitter is now well understood
from both a theoretical and practical point of view.
In the nineteenth century, scientists, mathematician, engineers and innovators started
investigating electromagnetism. The theory that underpins wireless communications was
formed by Maxwell. Early demonstrations took place by Hertz, Tesla and others. Marconi
demonstrated the first wireless transmission. Since then, the range of applications has
expanded at an immense rate, together with the underpinning technology. The rate of
development has been incredible and today the level of technical and commercial maturity
is very high. This success would not have been possible without understanding radio-
wave propagation. This knowledge enables us to design successful systems and networks,
together with waveforms, antennal and transceiver architectures. The radio channel is the
cornerstone to the operation of any wireless system.
In recent years, the research and developments in the area of RF and microwave
technologies have progressed significantly due to the growing demand for applica-
bility in wireless communication technologies. Starting from 1992, wireless com-
munication technologies have become quite mature. In the modern era of electronic
developments, design of wireless handsets is an example of integration of many di-
verse skill sets. Classical books in the areas of microwave technology provide us
with an in-depth knowledge of electromagnetic fundamentals.
The radio spectrum is one of the most precious resources which must be managed
to ensure efficient access for the wireless communication services which use it. The
allocation and management of spectrum are administered by the regulatory
authorities. Traditionally, spectrum allocation is carried out exclusively of its use in
large geographic areas and assigning frequency bands to specific users or service
providers is proved to be inefficient. Recently, substantial knowledge about
dynamic spectrum access scheme has been accumulated to enable efficient spectrum
sharing.
The ability to analyze system or circuit behavior is one of the key requirements for
successful design. To put an idea to work, a designer needs both the knowledge
and tools for analyzing the behavior of that new system architecture or that experi-
mental circuit topology. Design decisions are grounded on the results obtained from
analysis.
Describing the relevant detection and estimation theory, this detailed guide provides
the background knowledge needed to tackle the design of practical WLAN positioning
systems. It sets out key system-level challenges and design considerations in increasing
positioningaccuracyandreducingcomputationalcomplexity,examinesdesigntradeoffs,
and presents experimental results.
