Digital imaging devices, computer-based image-management systems, and radiology information systems (RIS) are the three building blocks that serve as the foundation for the all-digital practice of radiology (1). In the first instance, these digital technologies have been used simply to replace the analog imaging systems and the manual information and film-handling systems, used historically for...

This study is to assess PBB in Shiraz municipality. So a questionnaire was issued and a model was proposed to assess the possibility of PBB. Based on SHAH model the study findings concerning the subjects were negative in relation to three authority dimensions namely the authority to assess the performance and human and technical abilities and there is not the authority necessary to execute PBB ...

The switched-current (SI) circuit is a circuit technique which is able to realize analog sampled-data circuits with a standard CMOS technology. Among all the basic SI circuits, the memory cell circuit is the most primitive element. In this work, a practical SI memory cell which employs negative feedback circuitry and glitch reduction technique is first presented. Based on this basic cell, a uni...

This paper presents two prototypes of low power low voltage current mode 9 bit pipelined a/d converters. The first and the second converters are configured of 1.5 bit and 2.5 bit stages, respectively. The a/d converter structures are composed of current mode building blocks and final comparator block which converts the analog current signal into digital voltage signal. All building blocks have ...

We describe recent progress in integrated microwave photonics in wideband signal processing applications with a focus on the key signal processing building blocks, the realization of monolithic integration, and cascaded photonic signal processing for analog radio frequency (RF) photonic links. New developments in integration-based microwave photonic techniques, that have high potentialities to ...

A function dependent on the solution of a set of differential equations containing adjust~ able parameters, can be minimized by systematic search procedures in parameter space. Such procedures can be implemented by a hybrid system consisting of a general purpose analog computer and a digital expansion providing parallel logic building blocks. Programming of such a system is illustrated for a si...

One of the distinct advantages of switched-capacitor (SC) circuits is that they are compatible with existing CMOS technology. Hence, they are among the most popular analog building blocks. However, the standard design methodology assumes the use of infinite gain and infinite bandwidth operational amplifiers. The gain limitation of operational amplifiers introduces finite gain error. Section 2 o...

The purpose of this review is to discuss recent developments occurring at the interface of cosmology with string and M-theory. We begin with a short review of 1980s string cosmology and the Brandenberger-Vafa mechanism for explaining spacetime dimensionality and then introduce the Pre-Big-Bang scenario (PBB), the work of Hořava-Witten and Lukas, Ovrut and Waldram, and end with a discussion of t...

This is a summary of a course given at the Fourth Mexican School on Gravitation and Mathematical Physics on some aspects of PBB cosmology. After introductory remarks the lectures concentrate on some amusing consequences derived from the symmetries of the string theory with respect to such classical concepts as isotropy and homogeneity. The extra dimensions and the symmetries of the M theory are...