Orthogonal Frequency Division Multiplexing (OFDM) is one of recent years multicarrier modulation used in order to combat the Inter Symbol Interference (ISI) introduced by frequency selective mobile radio channel. The circular extension of the data symbol, commonly referred to as cyclic prefix is one of the key elements in an OFDM transmission scheme. This paper study The influence of the cyclic prefix duration on the BER performance of an OFDM-VCPL (Orthogonal frequency division multiplexing - Variable Cyclic Prefix Length) system and the conventional OFDM system with frame 64-QAM modulation is evaluated by means of computer simulation in a multipath fading channel. The adaptation of CP is done with respect to the delay spread estimation of the channel.
BSTRACT: BACKGROUND: Acne vulgaris(AV)is chronic inflammatory disease of pilosebaceous unit of young people. Patients with acne with or with out scarring might differ in regard to their immunological background from those free from acne. OBJECTIVES: To evaluate the problem of facial AV especially patients with scarring and to determine the frequency of associated skin diseases and to be compared with acne free control. METHODS: A cross sectional randomized controlled epidemiological study was conducted from Oct.2005-Oct. 2006.Three hundred students from Basra University; 132 (44%) males and 168 (56%) females were enrolled, their ages ranged from 18-25 (20.9±1.8) years. They were divided into: Group A those free from acne (98 individuals),G
... Show MoreS Khalifa E, AH Khalil I, N Adil A, AB Razan A…, 2009
The purpose of this research is to identify the youth issues in Talk Shows in the Iraqi satellite channels via monitoring a sample of episodes of the Talk Shows episodes which are concerned and analyzed the youth issues in the Iraqi satellite channels, namely, «Hala Shabab Program» at Al-Iraqia satellite Channel and «Shabab wa Banat Program» at Al-Sumaria satellite Channel by recording and re-watching them again. This research is classified as one of descriptive researches. The survey method was adopted in this study.
For this purpose, the researcher prepared an analysis form. The researcher de
... Show More Purpose - The study aimed at evaluating the accounting system of the Iraqi political parties, which is applied according to legislative texts, and then the ability to provide accounting information to evaluate the strategic performance and control of the party's operational and financial performance.
Findings- The research found that the unified accounting system applied to political parties does not provide relevance informations to judge the performance of the political party, the researcher a proposal for an accounting system that provides the necessary information to measure and monitor the performance of Iraqi political parties can be presented. The
A novel analytical method is developed for the determination of azithromycin. The method utilizes continuous flow injection analysis to enhance the chemiluminescence system of luminol, H2O2, and Cr(III). The method demonstrated a linear dynamic range of 0.001–100 mmol L-1 with a high correlation coefficient (r) of 0.9978, and 0.001–150 mmol L-1 with a correlation coefficient (r) of 0.9769 for the chemiluminescence emission versus azithromycin concentration. The limit of detection (L.O.D.) of the method was found to be 18.725 ng.50 µL−1 based on the stepwise dilution method for the lowest concentration within the linear dynamic range of the calibration graph. The relative standard deviation (R.S.D. %) for n = 6 was less than 1.2%
... Show MoreObjective : The study was carried out to construct an initial assessment documentation tool for nursing
recording system in Coronary Care Unit.
Methodology : A descriptive, purposive sample of (65) nurses was selected from CCU of main
teaching hospitals (Al Karama, Al Kindy, Al Kadimia, Al Yarmmok, Baghdad teaching hospital, Ibn
Al Naffis hospital) and Ibn-Al betar hospital in Baghdad city from the 15th of April 2004 to the 15th of
April 2006.
The instrument was constructed and comprised of two sections: section one included the
nurses' demographic characteristic; section two was the initial assessment documentation tool that
contained (2) parts including: General information form and the initial assessment form.
Modern automation robotics have replaced many human workers in industrial factories around the globe. The robotic arms are used for several manufacturing applications, and their responses required optimal control. In this paper, a robust approach of optimal position control for a DC motor in the robotic arm system is proposed. The general component of the automation system is first introduced. The mathematical model and the corresponding transfer functions of a DC motor in the robotic arm system are presented. The investigations of using DC motor in the robotic arm system without controller lead to poor system performance. Therefore, the analysis and design of a Proportional plus Integration plus Divertive (PID) controller is illustrated.
... Show MoreThe influence of 5-10 kHz audio frequency on the power dissipation in ac discharge of argon gas was studied experimentally, at pressures 50-80 mTorr and electrodes separation 10 cm (pd range 0.5-0.8 Torr.
cm). The measurements have shown that the discharge behavior in the ac circuit is equivalent to a series RC circuit. It is observed that the variation curve of discharge power P with the frequency f is approximately has a Gaussian shape. It is also observed that the curve of Pm- pd is the inverse of Paschen curve, where Pm is the maximum power in the frequency range. The time of breakdown is estimated from the curve of P- f.
In this research a new compounds were synthesized started from compound 1 which was synthesized from two moll of piperidine (secondary cyclic amine) with dichloro acetic acid, compound 1 reacted by condensation reaction with methanol and H 2 SO 4 as a catalyst to give the ester compound 2. Compound 2 was reacted with hydrazine hydrate 80 % to give compound 3 , then the compounds 4-13 were synthesized from refluxing of compound 3 with the selected aldehydes and ketones via using few drops of glacial acetic acid, finely step the compounds 4-13 were reacted with phtalic anhydride to give compounds 14-23.. All these compounds were characterized by using of melting point, FTIR, 1 HNMR and mass spectroscopy. Scheme 1 and Scheme 2 shown the all re
... Show MoreIt has become necessary to change from a traditional system to an automated system in production processes, because it has high advantages. The most important of them is improving and increasing production. But there is still a need to improve and develop the work of these systems. The objective of this work is to study time reduction by combining multiple sequences of operations into one process. To carry out this work, the pneumatic system is designed to decrease\ increase the time of the sequence that performs a pick and place process through optimizing the sequences based on the obstacle dimensions. Three axes are represented using pneumatic cylinders that move according to the sequence used. The system is implemented and
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