purpose : to present the clinical features, biomechanical properties and management of a patient who developed unilateral corneal ectasia after photorefractive keratectomy (prk) case report : the patient was a 24-year-old man without any obvious preoperative risk factor for ectasia who underwent bilateral prk. four years after keratorefractive surgery, the patient presented with loss of visual ...

phase sensitive detector described here has two principal applications: a- to produce a d.c out put proportional to- the amplitude of an incoming a,c signal and indicate, by the outut polarity, the phase of the signal with respect to an internal reference. b- to detect the presence of a signal of known phase and frequency which would otherwise be lost in «background noise» and to measure its am...

Abstract—In this paper, the problem of secure transmission in two-hop amplify-and-forward (AF) systems with an untrusted relay is investigated. To prevent the untrusted relay from intercepting the source message and to achieve positive secrecy rate, the destination-based cooperative jamming (DBCJ) technique is used. In this method the destination sends an intended jamming signal to the relay. T...

Free radicals are normally produced by living organism, at controlled production rate they perform physiological functions as signal transduction molecules. However, situations leading to an overproduction that surpasses antioxidant capacity creates oxidative stress. Consequently, damage to the cell membrane, protein, DNA and cell death are observed. Dairy cattle are susceptible to oxidative st...

in this paper, genetic programming is applied for quality improvement of noisy speech signal. therefore, a system including both spectral subtraction and genetic programming is implemented for speech enhancement. in the proposed method, first noise is reduced by spectral subtraction. in the next step, genetic programming trees are trained for more enhancement of noisy signal by mapping the sign...

Grid impedance estimation is used in many power system applications such as grid connected renewable energy systems and power quality analysis of smart grids. The grid impedance estimation techniques based on signal injection uses Ohm’s law for the estimation. In these methods, one or several signal(s) is (are) injected to Point of Common Coupling (PCC). Then the current through and voltage of ...

this paper addresses the signal processing principles in passive bistatic radar (pbr) systems. in this case, the detection problem in the presence of system noise, clutter/multipath, direct signal and interfering target signals is investigated. to this light, two types of detectors are studied. in the first one, which is based on intuitive sense, we examine two detectors. in the second type det...

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With the aim of reducing cost of electricity consumption and peak load reduction, tools requirement for better managing electricity consumption have become inevitable in recent years. Smart home has some equipment which are controllable and this ability is used for increasing comfort and minimizing electricity cost for residence. As a key component of smart home , Electric Vehicle(EV) ,increase...