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.
Asbestos is a hazard pollutant to human health, exposure to asbestos cause serious health effects and wide range of asbestos-related diseases such as asbestosis, lung cancer and malignant mesothelioma and it has been classified as carcinogen by the World Health Organization WHO which cause a carcinogenic effects. Fibers of asbestos are mainly released from friction product in brakes and clutch linings and from reinforce agent in the asbestos cement industry. The aim of this was to evaluate the levels of asbestos fibers in surroundings air of some dense traffic points in Baghdad, through winter 2020. Materials and Methods: Samples of airs was carried out by directing air flow to a mixed cellulose ester membrane filter mounted on an open face
... Show MoreThe study aims to reveal the degree of application of the alternative evaluation strategy in social studies in public education in the Kingdom of Saudi Arabia. It also aims to identify the opinions of experts on how to implement this. The study adopted the mixed methodology, which represented in the descriptive-analytical method, and qualitative methods through the grounded theory. The study used two tools namely: a questionnaire for assessments of social studies teachers and semi-structured interview questions. The results of the study showed a medium degree of appreciation for the application of alternative evaluation strategies by social studies teachers in general education with an average of (2.28). The results also showed that ther
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Design system often generated relationship within the frame work of their concept of interior design a system or more can be created between design relationships within this concept in the structure of its internal space product. Through the division of all to it parts to reveal the hidden places and stages of composition and their relationship and interdependence between them. And then re- composition of all its parts, doth in the deign process at the initial stages or in the processes of treatments that are necessary after the completion of design and circulation. To be able to use other events close to the first events designed for them. In terms of idea logical in fluency and its social, economic, cultural and political dimension. As
... Show MoreSurface water flow samples were collected with distances downstream over Saqlawiya main drain whose stretch of about 24.5 km. The drain travels through different land use pattern, before, flowing into Tigris River. Eight sampling points were carefully
selected downstream the channel during dry season. The examined water parameters were pH, NH3, NO3, PO= 4, BOD5, COD, TDS, S.S, Cl-, SO= 4, Na+ , Ca+2, Mg+2, and Oil and Grease. Descriptive and inferential methods through finding the best curve fit correlation were employed in the study to test the strength of the association between water chemical characteristics and distance downstream the channel. A comparison of the values of chemical parameters at the Al-Saqlawiya Drain-Tigris Riv
The study relied on data about the health sector in Iraq in 2006 in cooperation with the Ministry of Health and the Central Bureau of Statistics and Information Technology in 2007 Included the estimates of the population distribution of the Baghdad province and the country depending on the population distribution for 1997,evaluate the health sector which included health institutions, and health staff, and other health services. The research Aimis; Measurement an amount and size of the growth of health services (increase and decrease) and the compare of verified in Iraq and Baghdad, and evaluate the effectiveness of the distribution of supplies and health services (physical and human) of the size of the population distribution and
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There is poverty because of the difference in capacity and material resources, Previously poverty known on the basis of disparity between income and inadequate income. It realize later that fare wore effects of poverty is the erosion of human capital. The human poverty is the loss of food, education, health care and shelter.
In order to provide a database that target the poor , it have been propped a document on the features of poverty and the whereabouts of the poor and the rate of disparity between provinces.
Here the goal of the research is the identify the factors affecti
... Show MoreThis study has been conducted to know the level of microbial ( bacteria and fungi) contamination in 5 types of biscuits from local markets of Baghdad city. Fifty samples (ten sample for each kind of biscuit) were studed,Two are local,others are Iranian,Turkish,and Holandies. The following results have been achieved :1. The highest number of bacteria was 21.6×103 cell/g in Iranian biscuit while the lowest number was 14.3× 103 cell/g in local biscuit No.1 . The highest number of fungi was 16×103 colony/g and the lowest number was 5.3×103 colony/g in the Iranian and the local biscuit No.1,respectively.2. Staphylococcus aureus was the major bacteria appeared at highest level of 100% in Turkish biscuit. The lowest percentage was found in H
... Show MoreThe study highlights the rivalry of foreign interests in Iraq, especially after the establishment of the monarchy in 1921. This period was characterized by extensive American activity in Iraq in general and Baghdad in particular. This activity increased after the Americans obtained the concession which came in the light of Article IV of the 1930 Treaty. Which officially guaranteed US interests in Iraq. The research also discussed the efforts of the Jesuit Fathers in Baghdad to convert the Church of Wisdom from a place of worship and rites of the Christian religion to a school of the propagation of science and culture along the lines of American schools, College Baghdad), which has become an important school in Baghd
It boils down search is marked by (employing technology in the establishment of globalization in the Film Art), and walk parallel plan between the technical and artistic movements and the impact of globalization on the final performed in the film Film of innovations and technology and rapid capital that provided the filmmakers and Kartalatha which focused entirely in the embodiment of the idea and published in the service around the world. And distributes research on four chapters first chapter dealt with the methodological framework of the research, which included research problem marked by the following question: (What are the modalities to employ technology in the establishment of globalization in the Film Art?) And the importance of
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