Interference-Based Optimal Power-Efficient Access Scheme for Cognitive Radio Networks

In this paper, we propose a new optimization-based access strategy of multipacket reception (MPR) channel for multiple secondary users (SUs) accessing the primary user (PU) spectrum opportunistically. We devise an analytical model that realizes the multipacket access strategy of SUs that maximizes the throughput of individual backlogged SUs subject to queue stability of the PU. All the network receiving nodes have MPR capability. We aim at maximizing the throughput of the individual SUs such that the PU's queue is maintained stable. Moreover, we are interested in providing an energy-efficient cognitive scheme. Therefore, we include energy constraints on the PU and SU average transmitted energy to the optimization problem. Each SU accesses the medium with certain probability that depends on the PU's activity, i.e., active or inactive. The numerical results show the advantage in terms of SU throughput of the proposed scheme over the conventional access scheme, where the SUs access the channel randomly with fixed power when the PU is sensed to be idle

Gravity theory in SAP-geometry

The aim of the present paper is to construct a field theory in the context of absolute parallelism (Teleparallel) geometry under the assumption that the canonical connection is semi-symmetric. The field equations are formulated using a suitable Lagrangian first proposed by Mikhail and Wanas. The mathematical and physical consequences arising from the obtained field equations are investigated.Comment: 14 pages, References added and a reference updated, minor correction

The Role of the big five personality traits, proactive behaviour, and socialisation influences in newcomer adjustment

During the early stages of employment, newly hired employees find out what their new organisations are like. Their first impressions are extremely important in determining the course of subsequent attitudes and behaviour. Recently, a considerable progress has been made towards the understanding of adjustment process, however, the literature remain divided along a number of fronts. Moreover, newcomer research has been conducted independent and irrespective of newcomer personality individual differences. This seems to be a critical oversight because there is overlap in predictions involving these constructs. The current research extended the previous one by examining these multiple antecedents, including Big Five personality traits of newcomer to the tandem process of adjustment as well as outcomes that immediate, or ?proximal? to the process of newcomer adjustment. Following a cross sectional pilot study of recent college graduate, a three- wave longitudinal study of newcomers in seven organisations examined Big Five personality traits, proactive behaviour, and socialisation influence (formal training, leaders, co-workers) as antecedents of proximal adjustment outcomes (group integration, political knowledge of organisation, and task performance). The main study results suggested that personality traits were related to proximal adjustment outcomes, specifically, Conscientiousness was positively related to all proximal adjustment outcomes. Openness to experience was related to task performance and political knowledge. Group integration is independently related to Agreeableness, Extraversion and Neuroticism. The socialisation influence moderate these relations, for example, leader socialisation moderate Conscientiousness as it relates to political knowledge and group integration, while co-worker moderate Extraversion as it relates to task performance. Finally, it was found that, the relationship between proximal adjustment outcomes and the personality dimensions Openness was mediated by proactive behaviour. Overall, the results suggested that individual differences have a role in newcomer adjustment as it facilitate the socialisation influence, and Big Five was one of the key determinants of newcomer adjustment

Design of a Circular Concentric Microstrip Patch Antenna Array for WI-FI Band Energy Harvesting

Wireless networks have gone through unprecedented changes in the last decade owing to the rise in the number of users. Radio frequency (RF) energy harvesting (EH) (termed as RF-EH) can be a potential solution to exploit this traffic in communication systems, one of the key issues is designing a compact antenna array while providing reliable capturing characteristics over the operating band. In energy harvesting systems, printed slot antennas have received much attention owing to their matching characteristics. In addition, they present really appealing physical features, such as simple structure, small size, and low cost. In this paper, a small circular concentric antenna array utilizing rectangular radiating patch elements and defected ground structure for RF-EH is proposed. The antenna is designed using the CST Microwave Studio software package and realized on a Roger 5880 substrate with ���� = 2.2 and ℎ = 3.18 ����. The simulations demonstrated the effective performance of the proposed circular antenna array structure in terms of high gain of about 15.8 dBi, high efficiency, and the possibility to collect RF power from all direction

Management of glucose 6-phosphate dehydrogenase (G6PD) deficient patients undergoing open-heart surgery

Background: There are scarce studies on the management of glucose 6-phosphate dehydrogenase (G6PD) deficient patients during cardiac surgery. The purposes of this retrospective study were to present and evaluate our experience with G6PD deficient patients who underwent cardiac surgery with cardiopulmonary bypass (CPB). Methods: We included 20 patients with G6PD deficiency who had cardiac surgeries from 2015 to 2019. We used free radical scavenging strategy and careful perioperative management. The patients were compared to a control group of 20 patients with normal G6PD enzyme activity who underwent the same type of operations in the same period. Results: Males represented 80% of G6PD deficient patients. There were significant elevations in preoperative total bilirubin (1.03±0.33 vs. 0.57±0.11 mg/dl, p< 0.001) and reticulocytes (1.87±0.62 vs. 0.54±0.18%) in G6PD deficient patients. Valve surgery was done for 60% of G6PD deficient patients. There were no significant differences between both groups regarding the type of surgery, aortic cross-clamp, CPB, and total operative time. G6PD deficient patients had significantly lower postoperative hemoglobin levels (9.44±0.94 vs. 10.0±0.59 g/dl, p= 0.04) and significantly higher postoperative total bilirubin (1.51±0.51 vs. 0.98±0.45 mg/dl; p=0.002) and reticulocytes (1.85±0.51 vs. 0.57±0.13%; p< 0.001). There was no significant difference regarding postoperative urea and creatinine levels. Ventilation time (10.3±2.7 vs. 8.2±1.9 hours; p=0.01), ICU stay (3.1±0.87 vs. 2.3±0.71 days; p=0.004), and hospital stay (3.1±0.87 vs. 6.0±1.02 days; p<0.001) significantly increased in G6PD deficient patients. The mortality rate was 5% (one patient) in G6PD deficient patients. Conclusion: Despite the management strategy, G6PD deficient patients undergoing cardiac surgery are more liable to hemolysis and hypoxia with more need for blood transfusion and longer ventilation time, ICU, and hospital stays when compared to patients with normal G6PD enzyme activity. Further research to improve the outcomes in G6PD deficient patients is required

The Role of the big five personality traits, proactive behaviour, and socialisation influences in newcomer adjustment

During the early stages of employment, newly hired employees find out what their new organisations are like. Their first impressions are extremely important in determining the course of subsequent attitudes and behaviour. Recently, a considerable progress has been made towards the understanding of adjustment process, however, the literature remain divided along a number of fronts. Moreover, newcomer research has been conducted independent and irrespective of newcomer personality individual differences. This seems to be a critical oversight because there is overlap in predictions involving these constructs. The current research extended the previous one by examining these multiple antecedents, including Big Five personality traits of newcomer to the tandem process of adjustment as well as outcomes that immediate, or ?proximal? to the process of newcomer adjustment. Following a cross sectional pilot study of recent college graduate, a three- wave longitudinal study of newcomers in seven organisations examined Big Five personality traits, proactive behaviour, and socialisation influence (formal training, leaders, co-workers) as antecedents of proximal adjustment outcomes (group integration, political knowledge of organisation, and task performance). The main study results suggested that personality traits were related to proximal adjustment outcomes, specifically, Conscientiousness was positively related to all proximal adjustment outcomes. Openness to experience was related to task performance and political knowledge. Group integration is independently related to Agreeableness, Extraversion and Neuroticism. The socialisation influence moderate these relations, for example, leader socialisation moderate Conscientiousness as it relates to political knowledge and group integration, while co-worker moderate Extraversion as it relates to task performance. Finally, it was found that, the relationship between proximal adjustment outcomes and the personality dimensions Openness was mediated by proactive behaviour. Overall, the results suggested that individual differences have a role in newcomer adjustment as it facilitate the socialisation influence, and Big Five was one of the key determinants of newcomer adjustment.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Punching Capacity of UHPC Post Tensioned Flat Slabs with and Without Shear Reinforcement: An Experimental Study

Punching capacity is one of the main items in the design of both pre-stressed and non-pre-stressed flat slabs. All international design codes include provisions to prevent this type of failure. Unfortunately, there is no code provision for UHPC yet, and hence, the aim of this research is to experimentally investigate the impact of column dimensions and punching reinforcement on the punching capacity of post-tensioned slabs and compare the results with the international design codes’ provisions to evaluate its validity. The test program included five slabs with a compressive strength of 120 MPa: one as a control sample, two to study the effect of column size, and the last two to study the effect of punching reinforcement. Comparing the results with the design codes showed that ACI-318 is more accurate with an average deviation of about 5%, while EC2 is more conservative with an average deviation of about 20%. Besides that, punching reinforcement reduces the size of the punching wedge by increasing the crack angle to 28° instead of 22° for slabs without punching reinforcement. Also, the results assure that both ductility and stiffness are enhanced with the increased column dimensions and punching reinforcement ratio. Doi: 10.28991/CEJ-2023-09-03-06 Full Text: PD

Effect of Web Opening Location on Fatigue Assessment of H Section Steel Beams

In the last decades, steel beams with web opening were used extensively as useful structural and architectural elements due to their many advantages. In this research, steel beams with web opening subjected to static loading were modelled using the multi-purpose finite element software ANSYS and the finite element results were compared with previous research. Then, steel beams with a single web opening subjected to fatigue loading were investigated numerically. The effect of changing the location of web opening on the fatigue assessment of H section steel beams with web opening was studied taking normal stress into account. It was clear that, normal stress fatigue life of the steel beams was affected significantly by changing web opening location along the beam span when compared to a beam with solid web while the beam span, opening size and steel section were kept constant. The most convenient location of web opening along the beam span was found to be at mid span