37 research outputs found

    Resource Allocation for Tethered UAVs Aided NOMA Networks: A Location-Aware Air-Ground Collaborative Perspective

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    The research of the mutli-UAV assisted NOMA networks has received a lot of attention because of its superior ability to improve spectrum efficiency and high maneuverability simultaneously. In this research, we take into account downlink NOMA networks with multiple tethered UAV assistance, and investigate the joint UAVs location, user scheduling, user pairing and power distribution problem. The design aims to maximize the sum-rate that can be achieved with a minimum rate restriction, as a complex problem involving mixed-integer programming. First, we determine the best user pairing and power distribution methods for established UAVs positions, which gives the closed-form solution for parameters. Afterwards, we formulate the UAV position optimization problem as a local altruistic game from the viewpoint of air-ground cooperation on the bias of interference graphs. It has been shown to be an exact potential game that permits more than one pure approach Nash equilibrium (PNE). A centralized-distributed iterative learning method is proposed to reach the ideal PNE as rapidly as possible, maximizing the specified network utility measure. The proposed algorithm performs better than the current techniques, according to simulation findings, and greatly boosts network utility. Simulation results show that, nearly 5% and 26% networks utility can be enhanced by the proposed method compared with “head-pairs-tail” and random schemes respectively

    Association of insulin resistance with chronic kidney disease in non-diabetic subjects with normal weight.

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    OBJECTIVE: To the best of our knowledge, the association of insulin resistance (IR) with chronic kidney disease (CKD) has not been well studied in normal-weight individuals. The aim of this study is to examine whether IR is associated with CKD in non-diabetic subjects with normal weight. We also examine whether the presence of obesity modifies the association of IR with CKD. METHODS: Data were drawn from a cross-sectional survey in China. Both estimated glomerular filtration rate and urinary albumin to creatinine ratio were used as markers of CKD. Logistic regression models and the quartiles of homeostatic model assessment of insulin resistance were used to explore the associations of IR with CKD in entire cohort, normal-weight and overweight/obese subpopulations. RESULTS: In normal-weight subpopulation, the prevalence of IR and metabolic syndrome were 11.11% and 8.99%, respectively. In the entire cohort, the highest quartile HOMA-insulin resistance had a 70% increased risk for CKD (RR 1.70, 95% CI 1.07, 2.71, P=0.03, comparing the highest to the lowest quartile). However, when adding obesity to the model, the association was abolished. IR was associated with CKD in overweight/obese subpopulation but not in normal-weight subpopulation. CONCLUSION: IR and MetS in normal-weight individuals is common in the Chinese population. IR is associated with CKD in overweight/obese subpopulation but not in normal-weight subpopulation and the presence of obesity modifies the association of IR with CKD

    Association between Metabolic Syndrome and Chronic Kidney Disease in Perimenopausal Women

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    The purpose of the study was to explore the association between metabolic syndrome (MetS) and chronic kidney disease (CKD) in perimenopausal women. A cross-sectional study was conducted in Zhuhai from June to October 2012. Perimenopausal women (n = 685) were included in the study. All participants were divided into three subgroups: Group 1, 40 years old ≤ Age < 50 years old; Group 2, 50 years old ≤ Age < 60 years old; Group 3, 60 years old ≤ Age ≤ 65 years old. MetS was associated with CKD (p < 0.01) in the unadjusted analyses in total subjects. After adjusting the potential confounders, the odd ratios of CKD for MetS was 2.66 (95% CI 1.56 to 4.49, p < 0.001). There was no relationship between MetS and CKD in both Group 1 and Group 3. MetS was associated with CKD (p < 0.001) in the unadjusted analyses in Group 2. After adjusting for potential confounders, MetS was significantly associated with CKD. The odd ratios for MetS was 6.79 (95% CI 2.30 to 20.09, p < 0.001). There was no relationship between elevated blood pressure, elevated fasting glucose, abdominal obesity, Low HDL cholesterol, elevated triglycerides and CKD in both Group 1 and Group 3. Elevated blood pressure was associated with CKD in Group 2 (unadjusted Odds ratio: 4.52 (1.28–16.02), p = 0.02). After adjusting for potential confounders, there was no relationship between elevated blood pressure and CKD (p = 0.78). Elevated fasting glucose was associated with CKD in Group 2 (unadjusted Odds ratio: 3.69 (1.10–12.38), p = 0.03). After adjusting for potential confounders, there was no relationship between elevated fasting glucose and CKD (p = 0.15). There was no relationship between abdominal obesity, Low HDL cholesterol, elevated triglycerides and CKD in Group 2. These findings suggest that in perimenopausal women aged from 50 or older to 60 MetS was associated with CKD. There is no relationship between MetS and CKD in perimenopausal women aged from 40 or older to 50 and aged from 60 or older to 65
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