Joint Spectrum Sensing and Resource Allocation for OFDM-based Transmission with a Cognitive Relay

In this paper, we investigate the joint spectrum sensing and resource allocation problem to maximize throughput capacity of an OFDM-based cognitive radio link with a cognitive relay. By applying a cognitive relay that uses decode and forward (D&F), we achieve more reliable communications, generating less interference (by needing less transmit power) and more diversity gain. In order to account for imperfections in spectrum sensing, the proposed schemes jointly modify energy detector thresholds and allocates transmit powers to all cognitive radio (CR) subcarriers, while simultaneously assigning subcarrier pairs for secondary users (SU) and the cognitive relay. This problem is cast as a constrained optimization problem with constraints on (1) interference introduced by the SU and the cognitive relay to the PUs; (2) miss-detection and false alarm probabilities and (3) subcarrier pairing for transmission on the SU transmitter and the cognitive relay and (4) minimum Quality of Service (QoS) for each CR subcarrier. We propose one optimal and two sub-optimal schemes all of which are compared to other schemes in the literature. Simulation results show that the proposed schemes achieve significantly higher throughput than other schemes in the literature for different relay situations.Comment: EAI Endorsed Transactions on Wireless Spectrum 14(1): e4 Published 13th Apr 201

‘Convicted of Patricide?’: Robert Frost’s Nationalism in the Eyes of Contemporary Arab-American Women Writers

Given the culturally expansive nature of the American literary tradition of today, the question of the relevance of Robert Frost’s poetry to the poetry of contemporary Arab-American women writers is an issue worth digging into. Writing almost one hundred years ago does not make Frost’s poetry out of date. Frost’s poetry is as relevant to today’s America as it has been to the America of his days. And this can be ascribed to the multiplicity of perspectives he presents in his poetry as he examines crucial questions lying at the core of America’s “grand narrative of national development.” (Westover 2004: 216) Hence, the ambivalence which characterizes his national poetry. Reading Frost\u27s representation of subjects crucial to the American history in light of the contemporary Arab-American women writers’ can yield a better understanding of the ambivalent standpoint he adopts in most of his national poems. To achieve that, the discussion will analyze, compare and contrast the statements Frost and five contemporary Arab-American women writers (Naomi Shihab Nye, Lisa Suhair Majaj, Suheir Hammad, Mohja Kahf and Nathalie Handal) make on the crucial questions of national identity, citizenry and cross-cultural existence in a number of their selected poems. What place does Frost’s ambivalence find in their poetry? And to what extent is it shared or rejected? These questions, amongst others, will be addressed in the current study with the aim of assessing the impact of Frost’s oeuvre on the poetry of contemporary American poets of Arab descents

“Self-Wrought Homemaking”: Revisiting the Concept of the “Home” in the Poetry of Naomi Shihab Nye and Lisa Suhair Majaj

The study aims to investigate the changing perception of what constitutes the home in a number of selected poems by the Palestinian-American poets Naomi Shihab Nye and Lisa Suhair Majaj. As the home is constructed as a literary space rather than a physical place in their poetry, the traditionally established notion of the home as a “‘safe place’ that can exist unchanged by shifts of time or space” is refuted and is constructed as a “fertile site of contradictions demanding constant renegotiation and reconstruction.” The fixed perception of the home as a lost object in some of their poems, as well as the more realistic perception of the home as a substitute for the lost object in other poems are eventually replaced with a self-motivated realization of the need to free their perception from the essentialist categories of old and new, lost and retrieved through language. This realization on the part of the two poets is clarified by tracing, comparing and contrasting the change in the two poets’ perception of the home in a selection of their poems

Transculturalizing Space in Arab Diasporic Poetry: A Spatial Study of Naomi Shihab Nye’s Poetry Collection Transfer

In the aftermath of the spatial turn that started in the seventies of the previous century, much attention has been devoted to the representation of space in literary criticism. Prior to this, space either served as a background for the events in a literary work or was viewed within an extremely narrow scope which defined it as either central or peripheral. With such reductive readings, the need for a revolutionary critical approach to space in literary criticism has risen, not only in frequently read literary genres but in more recently developing ones. One case in point is Arab diasporic literature, in which space plays an integral role not only in shaping the diasporic relation to native and foreign lands, but in shaping the cross-cultural relations it engages in as well. In the poetry collection Transfer (2011) by the Palestinian-American author Naomi Shihab Nye, space is perceived beyond the physical reality of the native or the diasporic place which witnesses the interaction between the diasporic and the foreigner and is, therefore, transculturalized. As concluded from the analysis of a selection of the poems from Transfer, this transcultural space is marked a number of features. First, it cannot be defined geographically as central or peripheral, it cannot function outside a specific context, and it cannot be separated from the discourse of the text. In this sense, not only would adopting a spatial approach to Arab diasporic literature help deconstruct more traditional approaches to space, but it would also help address some of the most commonly raised questions in Arabic diasporic literature from a transcultural perspective

Recovery of pure Hesperidin from Iraqi Sweet Oranges Peel and study the effect in some bacteria

Citrus fruit contain variety of flavonoids such as Hesperidin (the principal flavonoid in oranges and grapefruit). Hesperidin is found in high concentration in fruit peel of oranges and in substantially lower concentration in juice of these fruits. Hesperidin was extracted from oranges peel by treating the peels with calcium hydroxide. HPLC technique was used to determine hesperidin. Hesperidin was saperated and purified in a purity of about 90.1-95.7% and yield about 1.5 %w/w from oranges peel dry powder. Both hesperidin and oranges peel extract showed significan antibacterial activity. Sensitivity to hesperidin and oranges peel extracts were not similar for the chosen bacteriaCrude orange peel extract gave a various antimicrobial activity agents Gram-positive Bacillus cereus, Staphylococcus aurous, Streptococcus pyogenus sp. and Gram-negative (Escherichia coli, Salmonella typhi) bacteria strains`. The minimum inhibitory concentration (MIC) values against these bacteria ranged from 45-175?g/disc.for crude orange peel extractand 175-450?g/disc for pure hesperidin In comparison to 30?g/disc reference standards ciproflaxacin and impinme.orange peel extract showed significant antimicrobial activity