Cooperative Access in Cognitive Radio Networks: Stable Throughput and Delay Tradeoffs

In this paper, we study and analyze fundamental throughput-delay tradeoffs in cooperative multiple access for cognitive radio systems. We focus on the class of randomized cooperative policies, whereby the secondary user (SU) serves either the queue of its own data or the queue of the primary user (PU) relayed data with certain service probabilities. The proposed policy opens room for trading the PU delay for enhanced SU delay. Towards this objective, stability conditions for the queues involved in the system are derived. Furthermore, a moment generating function approach is employed to derive closed-form expressions for the average delay encountered by the packets of both users. Results reveal that cooperation expands the stable throughput region of the system and significantly reduces the delay at both users. Moreover, we quantify the gain obtained in terms of the SU delay under the proposed policy, over conventional relaying that gives strict priority to the relay queue.Comment: accepted for publication in IEEE 12th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt), 201

Cooperation and Underlay Mode Selection in Cognitive Radio Network

In this research, we proposes a new method for cooperation and underlay mode selection in cognitive radio networks. We characterize the maximum achievable throughput of our proposed method of hybrid spectrum sharing. Hybrid spectrum sharing is assumed where the Secondary User (SU) can access the Primary User (PU) channel in two modes, underlay mode or cooperative mode with admission control. In addition to access the channel in the overlay mode, secondary user is allowed to occupy the channel currently occupied by the primary user but with small transmission power. Adding the underlay access modes attains more opportunities to the secondary user to transmit data. It is proposed that the secondary user can only exploits the underlay access when the channel of the primary user direct link is good or predicted to be in non-outage state. Therefore, the secondary user could switch between underlay spectrum sharing and cooperation with the primary user. Hybrid access is regulated through monitoring the state of the primary link. By observing the simulation results, the proposed model attains noticeable improvement in the system performance in terms of maximum secondary user throughput than the conventional cooperation and non-cooperation schemes

Parents’ Acceptance to Alveolar and Nasoalveolar Molding Appliances during Early Cleft Lip and Palate Care: A Call for High-Quality Research

AIM: Acceptance and compliance of the parents are an essential pillar in the success of pre-surgical infant orthopedic (PSIO) treatment. The aim of this systematic review is to evaluate the burden of care associated with the alveolar molding (AM) and nasoalveolar molding (NAM) appliances as experienced by the parents with unilateral complete cleft lip and palate (UCLP) infants. METHODS: An electronic search was carried on by two reviewers in eight search engines, as well as a manual search till July 2019. Randomized controlled trials (RCTs) comparing AM/NAM appliances to controls in infants with UCLP were selected. Risk of bias was evaluated using Cochrane risk of bias assessment tool for RCTs. RESULTS: One RCT was included in the qualitative analysis. Non-significant differences were found in the amount of mothers’ satisfaction between the intervention and control groups. CONCLUSIONS: Insufficient low-quality evidence is available regarding the effects of AM and NAM on parents’ satisfaction and burden of care. No conclusions can be withdrawn from the existing studies. High-quality research is needed to elucidate the degree of parents’ acceptance to the molding appliances. PROSPERO registration number: CRD42016043174

Behavior Of Trapezoidal Corrugated Girders webs with cutouts: Experimental and Analytical Solution

Corrugated steel-plate girders (GCWs) are nowadays used as structural elements in many applications for their high strength against shear buckling, otherwise cutouts are always provided in these plate elements to enable inspection and servicing. This study presents an experimental and analytical study for investigating the behavior of girders with corrugated webs (GCWs) having cutouts under shear loading. The experimental program was conducted on three full-scale plate girders, which have been tested under central load at mid-span. The theoretical analysis was conducted using ANSYS V20 to perform a nonlinear technique for the determination of the ultimate shear capacity of the tested girders. Finally, experimental, and finite element model were used to define the ratio of decreasing in carrying capacity for corrugated web, having cutout under shear loading. As expected from the ultimate strength, failure mechanism, and load-deflection curves that results of ultimate load carrying capacity decreased with the appearance of one or more cut-outs

Titrated Misoprostol Versus Dinoprostone for Labor Induction

Background: Misoprostol is as effective as dinoprostone for labor induction with low cost and temperature stability.Aim: This study designed to compare titrated misoprostol regarding its safety and efficacy with dinoprostone for induction of labor.Subjects and Methods: Women with a single pregnancy, above 37 weeks’ gestation, cephalic presentation, modified Bishop’s score <8, and not in labor with reassuring fetal heart rate, admitted for labor induction enrolled in this randomized controlled study. Studied women were randomized into; Group I: received oral misoprostol titrated in sterile water (200 μg tablet was dissolved in 200 ml sterile water [1 μg/ml]), starting dose of 20 μg misoprostol required, given every 2 h, and stopped if adequate contractions obtained and Group II: received vaginal dinoprostone tablet maximum two doses followed by augmentation of labor by oxytocin ± amniotomy if there is no uterine contractions after two doses of dinoprostone. In Group I, if the contractions were inadequate after two doses of oral titrated misoprostol (20 μg [20 ml]), the starting dose increased to 40 μg (40 ml), escalating the dose from 5 to 10 ml (45–50 μg), and 20 ml (60 μg) maximum ± amniotomy. If the uterine contractions were adequate, the next dose of misoprostol or dinoprostone was omitted. Statistical analysis done using Student’s t‑test for quantitative data and Chi‑square test for qualitative data.Results: Induction‑to‑delivery time was significantly longer in misoprostol than dinoprostone group (975 vs. 670 min, respectively), (P = 0.01). About 20.2% (21/104) of women in misoprostol group did not deliver vaginally within 24 h compared to 7.4% (8/108) in dinoprostone group (significant difference, P = 0.01). Augmentation of labor was significantly high in dinoprostone (37.96% [41/108]) compared to misoprostol group (10.6% [11/104]) (P < 0.01).Conclusion: Titrated misoprostol for induction of labor seems to be associated with significantly longer induction‑to‑delivery time, low incidence of vaginal birth within 24 h, and less need for augmentation of labor compared to vaginal dinoprostone.KEY WORDS: Dinoprostone, labor induction, titrated misoprosto