On the peak-to-average power of OFDM signals based on oversampling

Orthogonal frequency-division multiplexing (OFDM) introduces large amplitude variations in time, which can result in significant signal distortion in the presence of nonlinear amplifiers. We introduce a new bound for the peak of the continuous envelope of an OFDM signal, based on the maximum of its corresponding oversampled sequence; it is shown to be very tight as the oversampling rate increases. The bound is then used to derive a closed-form probability upper bound for the complementary cumulative distribution function of the peak-to-mean envelope power ratio of uncoded OFDM signals for sufficiently large numbers of subcarriers. As another application of the bound for oversampled sequences, we propose tight relative error bounds for computation of the peak power using two main methods: the oversampled inverse fast Fourier transform and the method introduced for coded systems based on minimum distance decoding of the code

Analysis of the Responsive Aspects of the Traditional Persian House

The traditional Persian house is a representative of the culture, way of life, and beliefs of the Persian people during the golden era of Persian civilization in 17th to early 20th centuries. The goal of this paper is to analyze the responsive features of this traditional house in order to provide a more organized recognition of this structure and its fundamental principles. It seems that appreciation of such key principles may help to exit the current confusion in understanding cultural-spatial qualities in contem- porary Iranian housing. In this regard, the paper will introduce the traditional Persian house, and will analyze its different aspects by using the seven criteria of Ian Bentley et al. in the book Responsive Environments (1985). This book speaks of broad, but somewhat universal concepts that can be applied across a wide range of areas such as old environments. This approach can be applied to reconsider the values of traditional environments. The criteria proposed are ‘permeability’, ‘variety’, ‘legibility’, ‘robustness’, ‘visual appropriateness’, ‘richness’ and ‘personalization’. This paper's analysis will be performed from three main viewpoints: functional-constructional, environmental, and social-cultural. The paper discussions show that the responsiveness criteria are achieved in the traditional Persian house. It seems this achie- vement results from intelligent application of fundamental, structural principles of the traditional Persian house that provides suitable ground for answering functional-constructional, environmental and social-cultural issues through common solutions in an integrated entity

Toward a convergent model of flexibility in architecture

With recent advances in technology, fundamental changes have occurred in architectural flexibility methods, a great deal of experience has been gained, and many strategies and tactics have been developed in this field. However, a convergence is lacking in these experiences, methods, and tactics, which raises a need for providing a convergent approach in this regard. In this paper, it is going to propose such a model of flexibility. To do this, it is first reviewed the general concepts of flexibility, and provide a short review of its history and its main executional tactics. It is then divided its main tactics into eight main groups of: ‘open plan’, ‘pre-fabricated modules’, ‘similar spaces’, ‘extendable unit᾽, ‘attachment and detachment of adjacent units’, ‘common space between adjacent units’, ‘portable walls’, and ‘retractable furniture in a multifunctional space’. Analyzing these tactics, it is extracted the three fundamental principles of flexibility: ‘soft connection’, ‘diversity and multiplicity of spaces’, and ‘multifunctional space’. Accordingly, this paper proposes a concise rule for flexibility as: ‘soft connections between spaces’ which implies to the three principles if some special attentions are paid. Although the rule seems to be simple, the paper argumentations show that paying attention to what it implies, can produce much more flexible spaces than what is created generally. At the same time, new creative ideas along supported by new emerging technologies can enrich these simple solutions extensively

Fractal-Based Image and Video Coding Using Matching Pursuit

188 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1997.This dissertation will also present a comparative study on the resolution enhancement of images using the inter-scale prediction inherent in the fractal transforms. (Abstract shortened by UMI.).U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD