Cognitive radio technology is used to improve spectrum efficiency by having the cognitive radios act as secondary users to access primary frequency bands when they are not currently being used. In general conditions, cognitive secondary users are mobile nodes powered by battery and consuming power is one of the most important problem that facing cognitive networks; therefore, the power consumption is considered as a main constraint. In this paper, we study the performance of cognitive radio networks considering the sensing parameters as well as power constraint. The power constraint is integrated into the objective function named power efficiency which is a combination of the main system parameters of the cognitive network. We prove the existence of optimal combination of parameters such that the power efficiency is maximized. Then we reformulate the objective function to incorporate the throughput. According to different constraints or degree of significance, we may put proper weight to each term so that we could obtain more preferable combination of parameters. Computer simulations have given the optimal solution curve for different weights. We can draw the conclusion that if we put more emphasis on power efficiency, the transmit power is a more critical parameter, however if throughput is more important, the effect of sensing time is significant.
إن تجسيد الشعراء للجمال واقامته تمثالا مصورا مرئيا ، كان الهدف منه اولا اشاعة جو نفسي مريح في مقدمات قصائد المديح ، فهو الجزء البصري الممتع لمدركات حسية اخرى ترافقه، وأما المرامي الاخرى
ﻓﮭﻲ إﻣﺘﺎع اﻟﻨﻔﺲ إﻣﺎ ﺑﺎﺳﺘﺮﺟﺎع أﺟﻤﻞ ﺻﻮرة أو أﻧﻤﻮذج ﻗﺎﺋﻢ ﻓﻲ اﻟﺬاﻛﺮة، وﺟﻌﻠﮫ ﯾﺤﯿﺎ ﻣﻦ ﺟﺪﯾﺪ ﻟﺪواﻋﻲ اﻟﺤﻨﯿﻦ للاماكن والازمنة الاثيرة . أو الميل للتعبير عن الوعي الجمالي الذي يتصل بموضوع الج
... Show MoreBackground: Cervical lymph nodes are the most frequently enlarged and biopsied of all the peripheral lymph nodes and in most of the cases the enlargement results from benign infectious causes, however, the presence of cervical lymphadenopathy (LAP) requires accurate diagnosis to exclude more serious causes. The aim of this study was to analyze cases of Iraqi patients presenting with cervical LAP who underwent surgical lymph node biopsy to establish accurate diagnosis. Materials and Methods: This retrospective study included 25 patients who presented with cervical LAP for whom surgical biopsy was performed to establish a definitive diagnosis. The investigated data included the demographic and clinical parameters in addition to the final his
... Show MoreThe research tagged (Digital Collage in Contemporary Art) consisted of four chapters. The first chapter was devoted to the methodological framework of the research. The problem ended with the following questions: How does digital collage represent contemporary art? What is the variable at the level of meaning shifts in composing works according to the digital collage? Was the digital collage a qualitative leap in the path of the aesthetic pattern in art? How does digital collage interfere with contemporary life and societies? It included the aim of the research and its importance, while the second chapter dealt with two topics, the first (reading in the concept of collage), and the second (digital collage). The third chapter was devoted
... Show MoreThis research deals with dialogic submission as one of the most important deliberative topics in the process of linguistic communication between the two sides of the discourse, and therefore we find in this research its concept among the ancient Arabs of grammarians, rhetoric and fundamentalists, and we started with Western linguists as a result of their knowledge of the philosophy of language, and this research was satisfied with the principle of cooperation that came By Grace as the founder of this modern deliberative topic with an attempt to monitor this principle in the prophetic stories and the susceptibility of the stories to this kind of implicit communication, as the prophetic stories included multiple deliberative dimensions of
... Show MoreApical meristems, lateral buds, anthers of immature flowers and immature embryos of chickpea ( Cicer arietinum L.) were cultured on MS media with different growth regulators and incubated for 6 weeks at 25-27?C with 16 hrs photoperiod for callus initiation. Results indicated that 1 and 0.1 mg/l of 2,4-D and BA were suitable for callus initiation when apical meristems and lateral buds were used. While 2 and 0.5 mg/l of both growth regulators were essential for immature embryos. It was noticed that using chickpea anthers of the MS medium must contain 1mg/l 2ip and 0.5 mg/l IAA. However, MS medium supplemented with 1-3 mg/l of BA and 2,4-D respectively was good for callus initiation from lateral buds, anther and immature embryos.
... Show More
Abstract :
The study seeks to highlight the importance of moderate religious discourse and dialogue and the rejection of extremist discourse that renews the crises and wounds of history. And that is through the means and efforts exerted, which is changing the extremist religious discourse to a moderate religious discourse, as well as calling on religious figures, whether they are followers of Judaism, Christianity or Islam, to search for a common ground for understanding and coexistence, because extremism in the name of God is the enemy for all and not for countries or religions in particular.
Also, through the necessity of confronting terrorist threats by making more efforts
... Show MoreThis research deals with the phenomenon of a similar voice phenomenon has founded
its own laws similar and includes the following phenomenon:
Azahrh aledgam: and Qdbent Tarifaoshrooth or dinaces and reflects the correlation
between language and reading and then apply the provision in sura blessed.
Phenomenon Alaalal and substitution, Two of the important acoustic phenomenon the
linguistic heritage has shown Alaalal types and the difference between him and the
substitution then counted their applications in Sura.
Similar phenomena: in name and deed shares bult causes and probability voices and
sound that refrais where tilt.
Background: Bone cutter is widely used in the
Middle east area to cut the prepuce during circumcision.
Results :One hundred twenty one male neonates
were included in this study.The mean operative
time (MOT) was 6 minutes, mean time of
healing (MTH) was 5 days, 7 cases (5.9%)
developed early & late complications, 2 (1.7%)
had bleeding, 3 (2.5%) developed infection, 2
(1.7%) developed late complications in the form
of meatal stenosis.
Settings:Al-Yarmouk Teaching Hospital and a
private surgical clinic.
Aim of the study: To assess the safety of
circumcision using bone cutter.
Methods: Over 6 years period from Jan. 2000
till Dec. 2005, one hundred twenty one male
neonates were circumci