Cutoff rate for fixed-composition on-off keying over direct detection photon channels

Cataloged from PDF version of article.[Ankara]: The Department of Electrical and Electronics Engineering and the Institute of Engineering and Sciences of Bilkent Univ., 1990.Includes bibliographical references (p.50-51).In this thesis, we consider direct detection photon channel with peak and average power constraints. This channel is modelled as a binary input discrete memoryless channel. We study the cutoff rate for different modulation formats on this channel since it is a measure of decoding complexity when sequential decoding is used and also, it gives an upper bound for the probability of error which decreases exponentially with the constraint length of convolutional code. Cutoff rates for the ensembles of fixed-composition and independent-letters codes along with ON-OFF keying are computed numerically and also some bounds are given. Cutoff rates versus signal-to-noise ratio or peak power are plotted for blocklengths of N=40,100 and for both ensembles. Comparison of cutoff rates for these two ensembles shows that for the direct detection photon channel the cutoff rate of fixed-composition ensemble is significantly greater than that of independent-letters ensemble for small values of signal-to-noise ratio and when the average power is a small fraction of peak power, say, 5-30%. In an uncoded system, for achieving a probability of error P(E)=(10 to the power -9), we should send 10 photons/slot with rate R=1 bit/slot, resulting in an efficiency of 0.1 bits/photon.However, using coding we can make probability of error arbitrarily small achieving an efficiency of 1 bit/photon. Also, some remarks on the implementation of fixed-composition trellis codes and on multi-level signalling instead of ON-OFF keying are given in conclusions.by Toygar, M. Şenol.M.S

Investigating the impact of overnight fasting on intrinsic functional connectivity: a double-blind fMRI study

Contains fulltext : 194413.pdf (publisher's version ) (Open Access

Clinical, genetic, and structural basis of apparent mineralocorticoid excess due to 11β-hydroxysteroid dehydrogenase type 2 deficiency

Mutations in 11β-hydroxysteroid dehydrogenase type 2 gene (HSD11B2) cause an extraordinarily rare autosomal recessive disorder, apparent mineralocorticoid excess (AME). AME is a form of low renin hypertension that is potentially fatal if untreated. Mutations in the HSD11B2 gene result either in severe AME or a milder phenotype (type 2 AME). To date, ∼40 causative mutations have been identified. As part of the International Consortium for Rare Steroid Disorders, we have diagnosed and followed the largest single worldwide cohort of 36 AME patients. Here, we present the genotype and clinical phenotype of these patients, prominently from consanguineous marriages in the Middle East, who display profound hypertension and hypokalemic alkalosis. To correlate mutations with phenotypic severity, we constructed a computational model of the HSD11B2 protein. Having used a similar strategy for the in silico evaluation of 150 mutations of CYP21A2, the disease-causing gene in congenital adrenal hyperplasia, we now provide a full structural explanation for the clinical severity of AME resulting from each known HSD11B2 missense mutation. We find that mutations that allow the formation of an inactive dimer, alter substrate/coenzyme binding, or impair structural stability of HSD11B2 yield severe AME. In contrast, mutations that cause an indirect disruption of substrate binding or mildly alter intramolecular interactions result in type 2 AME. A simple in silico evaluation of novel missense mutations could help predict the often-diverse phenotypes of an extremely rare monogenic disorder

COMPUTATION OF STRESS INTENSITY FACTORS OF AN AXISYMMETRIC INFINITE CYLINDER HAVING A TRANSVERSE CRACK

This paper considers the problem of an axisymmetric infinite cylinder with a crack at z = 0. The cylinder is under the action of uniformly distributed axial tension applied at infinity and its lateral surface is free of traction. It is assumed that the material of the cylinder is linearly elastic and isotropic. Crack surfaces are free. Formulation of the boundary problem under consideration is reduced to single singular integral equation in terms of the derivative of the crack surface displacement. These equations together with the single-valuedness and equilibrium condition for the displacements around the crack is converted to a system of a linear algebraic equation which is solved numerically. Stress intensity factors are calculated and presented in graphical form

SOLARUX CSP Greenhouse, Cultivates Agricultural Products, Generates Electrical Energy, Industrial Fruit and Vegetables Drying with Wasted Heat Energy

In sunny developing countries, the majority of the population depends on home-grown agricultural products. In this paper, it has been focused on designing and developing such a system, which generates the electricity and agricultural production with the remaining energy from the electricity generation, and drying the agricultural product so as to increase the value added and to make the investor more attractive by shortening the depreciation periods of the investment. It will be possible to grow agricultural products, dry agricultural products and generate electricity for 12 months in the greenhouses with this presented project. Solidworks 2016 program package has been used for the designing the greenhouse

LOWER CONSTRUCTION OF SOLARUX CSP GREENHOUSE, PROVIDES EXTRA INCOMES IN ADDITION TO ELECTRICITY GENERATION WITH NEW DESIGNED CSP DISH MIRRORS

Nowadays, new energy resources are required because of the growing energy demand, and main income source of sunny developing countries is home-grown agricultural products. Aim of this paper is to design and develop a CSP Greenhouse system that generates the electricity, produces agricultural products and dries agricultural products with the remaining energy from the electricity generation. New CSP dish mirror design consists of flat mirrors to concentrate the sun rays, which has the features of parabolic mirror system but much cheaper and also follows the sun in two axis. With the additional incomes provided by agricultural production and agricultural product drying, cost effectiveness of the system increases and the depreciation period of the investment shortens. It will be possible to grow agricultural products, dry agricultural products and generate electricity for 12 months in the greenhouse with this presented project. Solidworks 2016 program package has been used for the designing the parts of the greenhouse

Cracked infinite cylinder with two rigid inclusions under axisymmetric tension

This paper considers the problem of an axisymmetric infinite cylinder with a ring shaped crack at z = 0 and two ring-shaped rigid inclusions with negligible thickness at z = +/- L. The cylinder is under the action of uniformly distributed axial tension applied at infinity and its lateral surface is free of traction. It is assumed that the material of the cylinder is linearly elastic and isotropic. Crack surfaces are free and the constant displacements are continuous along the rigid inclusions while the stresses have jumps. Formulation of the mixed boundary value problem under consideration is reduced to three singular integral equations in terms of the derivative of the crack surface displacement and the stress jumps on the rigid inclusions. These equations, together with the single-valuedness condition for the displacements around the crack and the equilibrium equations along the inclusions, are converted to a system of linear algebraic equations, which is solved numerically. Stress intensity factors are calculated and presented in graphical form

Fracture and fatigue analysis of an agitator shaft with a circumferential notch

WOS: 000240013600006This paper is concerned with the fracture analysis of an agitator shaft of a large vessel and predicting its high cycle fatigue life. The agitator shaft has a circumferential notch around it and is subjected to remote bending and torque created by the mixing operation. The problem is comprised (i) the analyses of the bending force and torque acting on the agitator by using the analytical method, (ii) calculation of stress intensity factors under mode I and III loading conditions by using finite element method and, (iii) fatigue analysis of the agitator shaft failed in service. An agitator model is set up and data obtained from the agitator are processed to make more realistic approximations for bending forces, since they form a base for stress analysis, in which mode I stress intensity factors are evaluated. Mode I stress intensity factors obtained by finite element analysis are compared with the results provided by using the body force method. (c) 2006 Elsevier Ltd. All rights reserved