The inefficient use of spectrum is the key subject to overcome the upcoming spectrum crunch issue. This paper presents a study of performance of cooperative cognitive network via hard combining of decision fusion schemes. Simulation results presented different cooperative hard decision fusion schemes for cognitive network. The hard-decision fusion schemes provided different discriminations for detection levels. They also produced small values of Miss-Detection Probability at different values of Probability of False Alarm and adaptive threshold levels. The sensing performance was investigated under the influence of channel condition for proper operating conditions. An increase in the detection performance was achieved for cognitive users (secondary users) of the authorized unused dynamic spectrum holes (primary users) while operating in a very low signal-to-noise ratio with the proper condition of minimum total error rate.
In this paper, variable gain nonlinear PD and PI fuzzy logic controllers are designed and the effect of the variable gain characteristic of these controllers is analyzed to show its contribution in enhancing the performance of the closed loop system over a conventional linear PID controller. Simulation results and time domain performance characteristics show how these fuzzy controllers outperform the conventional PID controller when used to control a nonlinear plant and a plant that has time delay.
There are many techniques for face recognition which compare the desired face image with a set of faces images stored in a database. Most of these techniques fail if faces images are exposed to high-density noise. Therefore, it is necessary to find a robust method to recognize the corrupted face image with a high density noise. In this work, face recognition algorithm was suggested by using the combination of de-noising filter and PCA. Many studies have shown that PCA has ability to solve the problem of noisy images and dimensionality reduction. However, in cases where faces images are exposed to high noise, the work of PCA in removing noise is useless, therefore adding a strong filter will help to im
... Show MoreIn this paper, variable gain nonlinear PD and PI fuzzy logic controllers are designed and the effect of the variable gain characteristic of these controllers is analyzed to show its contribution in enhancing the performance of the closed loop system over a conventional linear PID controller. Simulation results and time domain performance characteristics show how these fuzzy controllers outperform the conventional PID controller when used to control a nonlinear plant and a plant that has time delay.
An experimental and theoretical study has been done to investigate the thermal performance of different types of air solar collectors, In this work air solar collector with a dimensions of (120 cm x90 cm x12 cm) , was tested under climate condition of Baghdad city with a (43° tilt angel) by using the absorber plate (1.45 mm thickness, 115 cm height x 84 cm width), which was manufactured from iron painted with a black matt.
The experimental test deals with five types of absorber:-
Conventional smooth flat plate absorber , Finned absorber , Corrugated absorber plate, Iron wire mesh on absorber And matrix of porous media on absorber .
The hourly and average efficiency of the collectors
... Show MoreDBN Rashid, Astra Salvensis, 2018 - Cited by 1
SMNs like Facebook, YouTube, Twitter, WhatsApp,..etc. are among the most popular sites on the Internet. These sites can provide a powerful means of sharing, organizing, finding information and knowledge. The popularity of these sites provides an opportunity to measure the use them in knowledge sharing, which needs a special scale, but unfortunately, there is no special scale for that. Thus, this study supposes to use SCT as a scale to measure the use of SMNs in electronic knowledge sharing due to it has been used to measure knowledge sharing with its traditional form. This study can help the decision-makers to use these SMNs to share the academics’ knowledge in educational institutes to the communi
... Show MoreIn the present paper, discuss the concept of fuzzy topological spectrum of a bounded commutative KU-algebra and study some of the characteristics of this topology. Also, we show that the fuzzy topological spectrum of this structure is compact and T1 -space.
Matching between wind site characteristics and wind turbine characteristics for three selected sites in Iraq was carried out. Site-turbine matching for potential wind power application in Iraq has not yet been well reported on. Thus, in this study, five years’ wind speed data for sites located in Baghdad (33.34N, 44.40E), Nasiriyah (31.05N, 46.25E), and Basrah (30.50N, 47.78E) were collected. A full wind energy analysis based on the measured data, Weibull distribution function, and wind turbine characteristics was made. A code developed using MATLAB software was used to analyse the wind energy and wind turbines models. The primary objective was to achieve a standard wind turbine-site matching based on the capacity factor. Another matching
... Show MoreA program in Visual Basic language was designed to calculate the time interval of radio storm by predict their type at specific Local Time (LT) from Baghdad location, such storms result from the Central Meridian Longitude (CML) of system ΙΙΙ for Jupiter and phase of Io’s satellite (ФIo). These storms are related to position of Io (Io- A,B,C,D). The input parameters for this program were the observer’s location (longitude), year, month and day. The output program results in form of tables provide the observer information about the date and the LT of beginning and end of each type of emitted storm. The year 2011 was taken to apply the results within twelve month; the results of the time interval of radio storm were between (0.08h-5
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