In this paper, we use concepts and results from percolation theory to investigate and characterize the effects of multi-channels on the connectivity of Dynamic Spectrum Access networks. In particular, we focus on the scenario where the secondary nodes have plenty of vacant channels to choose from-a phenomenon which we define as channel abundance. To cope with the existence of multi-channels, we use two types of rendezvous protocols: naive ones which do not guarantee a common channel and advanced ones which do. We show that, with more channel abundance, even with the use of either type of rendezvous protocol, it becomes difficult for two nodes to agree on a common channel, thereby potentially remaining invisible to each other. We model this invisibility as a Poisson thinning process and show that invisibility is even more pronounced with channel abundance. Following the disk graph model, we define and characterize connectivity of the secondary network in terms of the available number of channels, deployment densities, number of transceivers per node, and communication range. When primary users are absent, we derive the critical number of channels which maintains super-criticality of the secondary network. When primary users are present, we characterize and analyze the connectivity for all the regions: channel abundance, optimal, and channel deprivation. Our results can be used to decide on the goodness of any channel rendezvous algorithm by computing the expected resultant connectivity.
Marriage is considered one of the strongest ties that links between two human beings , but after the evolutions that happened in our Arab communities and specifically in the Iraqi community , marriage through the internet websites appeared . this kind of marriage is considered one of the new phenomena that appeared in the present time in many societies. That was through internet websites like yahoo , Facebook and other websites that have chat features.
The Islamic sharia looks negatively at marriage through the internet announcing that this way is harmful for both the man and the woman
This article discusses some of the metaphorical use of language units. Here we will define the basic concepts and underline the causes of this phenomenon. Through research it is proven that through the application of names of some body parts achieves the variety of metaphorical meanings.
Forty eight isolates (41.02%) were obtained from 117 wound and burn samples. The isolates that showed high resistance for both antibiotic was two only that represent 4,1% from all isolates. The result of PCR product electrophoresis was referred that the gene is VIM gene. Lactose and raffinose showed double increasing in diameter of inhibition zone of imipenem with 1% that mean showed highest susceptibility that decreased with the concentration increasing, the same result were with meropenem. But no effect were detected on meropenem inhibition zone diameter. Mannose have no effect on the resistance in 1%, 3% and 7%. Results showed that only three case that increase the expression of gene, they were lactose at 1% concentration that increased
... Show Moreيعد التكرار من الظواهر الاسلوبية التي اتخذت دورها في بناء النص الشعري الحديث ويقوم على جملة من الاختيارات الاسلوبية لمادة دون أخرى ولصياغة لغوية دون سواها ، مما يكشف في النهاية عن سرّ ميل هذا النص الشعري أو ذاك لهذا النمط الاسلوبي دون غيره ، وعلى الرغم من ان التكرار يعد مسألة عامة وشائعة في العمل الأدبي ، فأن الاهتمام بهذا الجانب من المنهج الاسلوبي يأتي من جهة كونه مهيمناً له ايحاءاته ودلال
... Show MoreThe photoconductivity and its dependence on light intensity have been investigated in a-Ge20Se80 thin films as a function of temperature between (293–323)K. The result showed that the photoconductivity and photosensitivity increase with increase of annealing temperature. This behavior is interpreted in terms of the dispersive diffusion –controlled recombination of localized electrons and holes.
The rapid success and the field dilation of Daish organization in both Iraq and Syria make academic institutes and research centers to pay attention to its propaganda means to gain its public opinion, and to further investigation about new methods employed by this organization to disseminate its messages to the public, particularly young people in large areas of the world. This organization uses traditional propaganda techniques on psychological war and its levels, social network sites and platforms that are distributed online. This study seeks to expose more persuasive methods used by the organization to gain multiple classes of society and to disseminate its extremist ideological thoughts. It also studies the psychological operation an
... Show Moreلم تولد الجماهيرية العالية للسينما من فراغ، إنّما تحققت من إيمان المتلقي العميق، بأن الفيلم أبعد من محاولة للترفيه، فالسينما هي فلسفة العصر، التي تتناول القضايا المهمة لتقدمها عبر حكايتها مؤطّرة بمنطق محدّد ومدفوعة ببناء عاطفي مؤثر، يهيئ المتلقي للاهتمام بهذه القضايا واستيعابها، والتغير المناخي واحد من أهم المواضيع التي بدأت السينما في الحقبة السابقة بتبنيها وتقديمها ضمن بنى حكائية تزيد من وعي المتل
... Show Moreلقد انبثقت رؤيا حديثة في مسرح الثمانينات من القرن العشرين كان هدفها دحر حس الاسر الذي عاشه انسان العصر الحديث وفي محاولة للارتقاء بارادته وحرية الاختيار نحو الانعتاق من محاولات المصادرة الفظة لها. وبالرغم من افتراض هذه الرؤيا انها ذات طابع سلبي, الا ان رؤيا الانتحار قدعدت بانها قادرة على ان تجعل في متناول يد الانسان احساسا طموحا بالتحكم على الاقل بنوع النهاية التي يكتبها لحياته. وقد انعكست هذة الرؤيا ال
... Show More