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The electromagnetic (EM) spectrum is the lifeblood of wireless communications and services. Accessing the spectrum has become ever-increasingly problematic. This is due to the current practices of frequency management based on pre-planned and static frequency allocation and assignments that can no longer accommodate explosive demands for EM spectrum. Without a paradigm shift in spectrum management, the growth of wireless services to meet demands, whether from commercial, civil, or military interests, will be severely curtailed in the coming years. In particular, spectrum-dependent devices, equipment, and systems will increasingly encounter significant competitive disadvantages, with critical consequences on our warfighting capability, when accessing the (seemingly or actually) overcrowded EM spectrum upon deployment in the U.S., and more so overseas. On the road forward, the transformation of spectrum management from the current static spectrum allocation and assignment to a more dynamic and responsive regime is greatly facilitated by the emerging concept of dynamic spectrum access (DSA) that enables spectrum-dependent devices, equipment, and systems to dynamically change their parameters to adapt their spectrum access according to criteria such as policy constraints, spectrum availability, propagation environment, and application performance requirements. In this paper, we present an overview of DSA architectures - opportunistic as well as coordinated, highlight their salient features, and focus on their implications on radios, networks, and spectrum usage which will provide responsive tactical and enabling strategic capabilities to the warfighter.

"More than fifteen years after the success of the first edition, this sweeping introduction to the history of architecture in the United States is now a fully revised guide to the major developments that shaped the environment from the first Americans to the present, from the everyday vernacular to the high style of aspiration. Eleven chronologically organized chapters chart the social, cultural, and political forces that shaped the growth and development of American towns, cities, and suburbs, while providing full description, analysis, and interpretation of buildings and their architects. The second edition features an entirely new chapter detailing the green architecture movement and architectural trends in the 21st century. Further updates include an expanded section on Native American architecture and contemporary design by Native American architects, new discussions on architectural education and training, more examples of women architects and designers, and a thoroughly expanded glossary to help today's readers. The art program is expanded, including 640 black and white images and 62 new color images. Accessible and engaging, American Architecture continues to set the standard as a guide, study, and reference for those seeking to better understand the rich history of architecture in the United States"--

Planning and the Rural Environment.

In this article, we argue that Niklas Luhmann has a lot to offer present-day planning theory. Until now, planning theory has been engaged with Luhmann's work only minimally. Convinced of its potential, we want to show how Luhmann's systems theory offers fresh insight into both limits and possibilities of planning in contemporary society. We argue that Luhmann's understanding of society as functionally differentiated into self-referentially closed subsystems (politics, economy, law, science, etc.) creates space for a complex and subtle analysis of planning practice. In particular, we look at the role of planning within an autopoietic account of society, and its ability to steer other social subsystems. Planning is seen as the form of steering aiming to coordinate processes of spatial organization, therefore an activity dealing with steering problems. We illustrate key concepts of the systems theory in brief analyses of planning situations and interpret these situations using the systems theoretical framework. The analyses center around the questions of planning's steering capacity and the role of the planner, thus creating linkages with mainstream discussions in planning theory.

From the University of Alberta comes a coolness towards conventional design in research. The architects and administrators, in expressing their personalities, may not do well by the researcher's personality. Readers will recall Dr. Som mer's fables concerning keys and power and secretaries and research produc tivity.

We consider the division of a territory into administrative districts responsible for providing a set of goods and services to residents who aresensitive to service congestion. We deduce the optimal architecture of public governance (i.e. the division of government into several levels, thedistribution of services among them, their number of jurisdictions and the size of their administrations), which depends on how citizens weigh theperformance capacity of administrations and the services they produce. We compare it to a decentralized organization where each jurisdiction is free to choose the size and scope of its administration. The resulting architecture generally involves more countries with fewer levels of administration than the optimal one. We use our results to estimate citizen preferences using U.S. data. We find that the country is divided into two zones ("Northeast & West" and "Midwest & South") whose estimated values are statistically different.