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Channel assignment scheme in clustered multichannel cognitive radio networks with outdated CSI over Rayleigh fading channels 下载免费PDF全文
Akinbode A. Olawole Fambirai Takawira Olutayo O. Oyerinde 《International Journal of Communication Systems》2018,31(14)
This work investigates channel assignment for cooperative spectrum sensing in multichannel cognitive radio networks, where the heterogeneity of primary user (PU) activity and the effect of varying channel condition on the received signal‐to‐noise ratio during cluster formation are considered. With the objective to minimize interference to the PU while enhancing multiple spectrum utilization of the secondary user (SU), an overlapping cluster‐based assignment is formulated into a nonlinear integer optimization problem. To obtain an efficient solution, the nonlinear integer problem is transformed into a mixed integer linear problem, based on which, this paper proposes an exact solution and then two new heuristic algorithms for suboptimal solutions, respectively. Furthermore, a comparative study of four different cluster head selection schemes with respect to their performance in cooperative spectrum sensing, under cluster's heterogeneity in terms of SUs distribution relative to PU transmitter location is presented. Based on the study, a robust cluster head selection scheme is proposed. Simulation results show that good sensing performance and increased opportunistic spectrum utilization in multichannel cognitive radio networks are two sides of a coin that depend on the ratio of the SUs to the number of PU channels. How far away the PU is from the cluster center is also seen to be key in the optimal selection of cluster heads in cooperative spectrum sensing. 相似文献
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Ademola Adetokunbo Oyagbemi Temitayo Olabisi Ajibade Yapo Guillaume Aboua Idayat Titilayo Gbadamosi Aduragbenro Deborah A. Adedapo Abimbola Obemisola Aro Olumuyiwa Abiola Adejumobi Emma Thamahane-Katengua Temidayo Olutayo Omobowale Olufunke Olubunmi Falayi Taiwo Olaide Oyagbemi Blessing Seun Ogunpolu Fasilat Oluwakemi Hassan Iyanuoluwa Omolola Ogunmiluyi Olufunke Eunice Ola-Davies Adebowale Benard Saba Adeolu Alex Adedapo Sanah Malomile Nkadimeng Lyndy Joy McGaw Prudence Ngalula Kayoka-Kabongo Oluwafemi Omoniyi Oguntibeju Momoh Audu Yakubu 《Journal of Food Biochemistry》2021,45(2):e13604
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Ademola Adetokunbo Oyagbemi Foluso Bolawaye Bolaji-Alabi Temitayo Olabisi Ajibade Olumuyiwa Abiola Adejumobi Olumide Samuel Ajani Theophilus Aghogho Jarikre Temidayo Olutayo Omobowale Olufunke Eunice Ola-Davies Kehinde Olugboyega Soetan Abimbola Obemisola Aro Benjamin Obukowho Emikpe Adebowale Benard Saba Adeolu Alex Adedapo Matthew Olugbenga Oyeyemi Sanah Malomile Nkadimeng Prudence Ngalula Kayoka-Kabongo Lyndy Joy McGaw Oluwafemi Omoniyi Oguntibeju Momoh Audu Yakubu 《Journal of Food Biochemistry》2020,44(12):e13534
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BACKGROUND: Many children in rural communities of developing countries die of nutrition-related causes due to lack of nutrition education and low purchasing power of the families, which result in low-quality weaning foods and poor feeding practices. OBJECTIVE: To evaluate the nutritional composition of local weaning foods and their impact on child feeding practices among low-income Nigerian mothers. METHODS: A cross-sectional survey was conducted between March and June 2005 among 294 randomly selected pairs of nursing mothers and their children who attended the postnatal clinic of State Specialist Hospital and Comprehensive Health Centers in Akure community, Ondo State, Nigeria. A structured, self-or interviewer-administered questionnaire was used to collect information on infant demographic characteristics, feeding, and socioeconomic characteristics of the parents. The children's weights were recorded, and samples of the weaning foods were analyzed. RESULTS: The mothers' ages ranged from 22 to 37 years, and the children's from one to 12 months. Among the parents, two-fifths of the respondents worked as drivers, mechanics, carpenters, and the like, while the remaining respondents were civil servants, health professionals, teachers, merchants, and housewives. The educational attainment of the parents ranged from no formal education (1.4%) to higher education (46%); 13% had completed primary school, and 39.6% had completed secondary school. The average monthly family income was between 3,500 and 30,000 naira (US dollar 23.3-dollar 200). Among the children, 58.3% were of normal weight, 41.1% were mildly underweight, 0.3% moderately underweight, and 0.3% severely underweight; 23.1% were exclusively breastfed, 9.5% received breastmilk and traditional medicinal herbs, 15.6% received breastmilk and commercial weaning food, 7.4% received commercial weaning food only, 14.8% received local weaning foods only, 24.1% received local weaning foods plus breastmilk, and 5.8% received the family diet. CONCLUSIONS: We found that a high proportion of the nursing mothers used local ingredients to formulate weaning foods for their babies. The nutritional compositions of these foods is of high quality and are suitable as weaning foods, particularly for infants of low-income parents who do not have access to commercial weaning foods. 相似文献
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Olutayo Israel Falodun Emmanuel Olugbenga Ikusika 《The International journal of environmental studies》2020,77(5):865-875
ABSTRACT Gram-negative bacteria that produce Extended-spectrum beta-lactamase (ESBL) and metallo beta-lactamase (MBL) show resistance to beta-lactam antibiotics. This study was to determine Beta-lactamases-producing Pseudomonas species in fish ponds. Pseudomonas species isolated from aquaculture water samples using Pseudomonas base agar were characterised biochemically. The detection of ESBL and MBL was made by double disc synergy and imipenem-EDTA combined disc methods, respectively. Antimicrobial susceptibility was by disc diffusion method. The 94 Pseudomonas species isolated comprised P. aeruginosa (62.8%), P. stutzeri (14.9%), P. putida (9.8%) and P. fluorescens (12.8%). P. aeruginosa 16 (16.3%) and P. stutzeri 4 (4.3%) produced ESBL, but 2 (10%) P. aeruginosa and 1 (5%) P. stutzeri produced MBL. Resistance of ESBL producers to trimethoprim was 55.5% and 7 (35.0%) were multidrug resistant. Detection of ESBL and MBL in Pseudomonas spp. from this study implies environmental health risk. Antibiotics misuse in aquaculture and discharge of untreated aquaculture wastewater into the environment should be discouraged. 相似文献
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In this paper, we present computationally efficient iterative channel estimation algorithms for Turbo equalizer-based communication
receiver. Least Mean Square (LMS) and Recursive least Square (RLS) algorithms have been widely used for updating of various
filters used in communication systems. However, LMS algorithm, though very simple, suffers from a relatively slow and data
dependent convergence behaviour; while RLS algorithm, with its fast convergence rate, finds little application in practical
systems due to its computational complexity. Variants of LMS algorithm, Variable Step Size Normalized LMS (VSSNLMS) and Multiple
Variable Step Size Normalized LMS algorithms, are employed through simulation for updating of channel estimates for turbo
equalization in this paper. Results based on the combination of turbo equalizer with convolutional code as well as with turbo
codes alongside with iterative channel estimation algorithms are presented. The simulation results for different normalized
fade rates show how the proposed channel estimation based-algorithms outperformed the LMS algorithm and performed closely
to the well known Recursive least square (RLS)-based channel estimation algorithm. 相似文献
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Olalekan Adebayo Olayemi Adebowale Martins Obalalu Segun Emmanuel Ibitoye Khaled Al-Farhany Temidayo Samsudeen Jolayemi Abdulbaqi Jinadu Tomisin Favour Ajide Isaac Kayode Adegun 《亚洲传热研究》2023,52(7):4774-4797
A numerical study of mixed convective heat transfer in a lid-driven square enclosure containing a hot elliptic cylinder is conducted. The impacts of the Grashof number , Reynolds number , cylinder tilt angle , and aspect ratio have been examined for a fluid of of 0.71. The horizontal enclosure walls are insulated, while its vertical walls are restricted to a nonvarying temperature Tc, whereas a sinusoidal temperature of is imposed on the wall of the elliptical cylinder. The governing equations are solved using COMSOL Multiphysics 5.6 software. The fluid dynamic and the heat transport profiles between the enclosure and the elliptical cylinder walls are represented by the stream function, isothermal contours, and average Nusselt number. Results established that for all the considered aspect ratios, the thermal heating range of is predominantly a conduction mechanism. The critical position of the ellipse where the inclination effect becomes insignificant is determined by the Grashof number and aspect ratio when the Re = 100. The strength of vortices and cell numbers are significantly influenced by the aspect ratio, particularly when the . When , the average heat transfer from the cylinder remains the same regardless of the cylinder's orientation. The impact of cylinder orientation on heat transfer from the cylinder wall is minimal for . For AR values of , increasing the inclination angle does not result in improved heat transfer. The influence of the increasing inclination angle on the right wall diminishes as the angle increases, except when the Grashof number is greater than 105, where the rate of heat transfer is enhanced for inclination angles beyond 45°. 相似文献
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