In cognitive radio networks, there are two important probabilities; the first probability is important to primary users called probability of detection as it indicates their protection level from secondary users, and the second probability is important to the secondary users called probability of false alarm which is used for determining their using of unoccupied channel. Cooperation sensing can improve the probabilities of detection and false alarm. A new approach of determine optimal value for these probabilities, is supposed and considered to face multi secondary users through discovering an optimal threshold value for each unique detection curve then jointly find the optimal thresholds. To get the aggregated throughput over transmission

     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 achi

Cognitive radio is observed as a new approach, which could be cope with the spectral limitations. This approach is designed to detect whether a particular segment of the radio spectrum is currently in use and to jump into the temporarily unused spectrum rapidly without interfering with the transmissions of other users. CR is the promising radio technology which aims to detect and utilize the temporally unused spectrum bands by sensing its radio environment in order to improve spectrum utilization. To enhance the sensing performance, cooperative spectrum sensing has been proposed. However, when the number of cognitive user tends to be very large, the bandwidth for reporting sensing results to the common receiver will be very huge. In this pa

Cognitive radios have the potential to greatly improve spectral efficiency in wireless networks. Cognitive radios are considered lower priority or secondary users of spectrum allocated to a primary user. Their fundamental requirement is to avoid interference to potential primary users in their vicinity. Spectrum sensing has been identified as a key enabling functionality to ensure that cognitive radios would not interfere with primary users, by reliably detecting primary user signals. In addition, reliable sensing creates spectrum opportunities for capacity increase of cognitive networks. One of the key challenges in spectrum sensing is the robust detection of primary signals in highly negative signal-to-noise regimes (SNR).In this paper ,

The sensors based on Nickel oxide doped chromic oxide (NiO: Cr2O3) nanoparticals were fabricated using thick-film screen printing of sol-gel grown powders. The structural, morphological investigations were carried out using XRD, AFM, and FESEM. Furthermore, the gas responsivity were evaluated towards the NH3 and NO2 gas. The NiO0.10: Cr2O3 nanoparticles exhibited excellent response of 95 % at 100oC and better selectivity towards NH3 with low response and recovery time as compared to pure Cr2O3 and can stand as reliable sensor element for NH3 sensor related applications.

Gas sensors based on titanium dioxide (TiO₂) and zinc oxide (ZnO) nanocomposites are considered energy-saving devices that are utilized to find dangerous or harmful gases in an environment. The performance of nitrogen dioxide (NO₂) gas sensors have been improved by spin-coating a TiO₂ and TiO₂:ZnO nanocomposite with varying concentrations (₉₀TiO₂:₁₀ZnO, ₇₀TiO₂:₃₀ZnO, and ₅₀TiO₂:₅₀ZnO). To correlate structural properties with gas-sensing behavior, structural and morphological characterization has been done using FESEM, XRD, and EDX.  Without any ZnO-specific crystalline phase, TiO₂

      The Framework Convention on Tobacco Control is among the main agreements that dealt with the topic of tobacco control. In spite of the efforts made in this aspect by countries through the preparation and the speed of ratification, there are some obstacles that prevent the achievement of the objectives of the convention including the tobacco companies' pursuit of not   implementing the agreement in the necessary manner. In light of this, many countries and international organizations, foremost of which is the World Health Organization, have undertaken to overcome these obstacles. Among the efforts are those which are made in the framework of exchanging information, technical and spec

تقدمت احداث النصف الاخير من القرن الماضي من تاريخ العالم الاقتصادي صور كثيرة من التكتلات والاليات التعاونية والتشاركية القائمة على مصادر مختلفة للتجمع الاقتصادي من اهمها شكل الشراكات التجارية والاقتصادية ولها امثلة كثيرة على المستوى الاقتصادي الدولي ومنها الشراكة الاورومتوسطية التي تمثل منطقة حيوية في حسابات التبادل الدولي تجاريا وراسماليا ولكن هذا التشكيل التكتلي يحتاج الى وقفه تخص

Facts and information contained in the search show that Algerian Ottoman military cooperation began since correlation Algeria with the Ottoman Empire in 1518, which was achieved after the Ottoman sultan response to the request of Algerians; there was a remarkable collaboration, according to the available capacity, and according to their needs.
A manifestation of this cooperation can be seen land and sea army, which represented in the entry of the first squad of Janissary army to Algeria in 1519, and the formation of the Algerian fleet, which was an important force in Arab side of Mediterranean sea, but it loses its independent leadership when it reaches Istanbul and becomes part of the Ottoman fleet.
Also, military buildings repres