Deep Reinforcement Learning for Practical Phase Shift Optimization in RIS-aided MISO URLLC Systems

Reconfigurable intelligent surfaces (RISs) can assist the wireless systems in providing reliable and low-latency links to realize the requirements in Industry 4.0. In this paper, the practical phase shift optimization in a RIS-aided ultra-reliable and low-latency communication (URLLC) system at a factory setting is performed by applying a novel deep reinforcement learning (DRL) algorithm named as twin-delayed deep deterministic policy gradient (TD3). First, the system achievable rate in finite blocklength (FBL) regime is identified for each actuator then, the problem is formulated where the objective is to maximize the total achievable FBL rate, subject to non-linear amplitude response and the phase shift values constraint. Since the amplitude response equality constraint is highly non-convex and non-linear, we employ the TD3 to tackle the problem. The considered method relies on interacting RIS with industrial scenario by taking actions which are the phase shifts at the RIS elements, to maximize the total FBL rate. We assess the performance loss of the system when the RIS is non-ideal, i.e., non-linear amplitude response with/without phase quantization and compare it with ideal RIS. The numerical results show that optimizing phase shifts in non-ideal RIS via the considered TD3 method is highly beneficial to improve the performance.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

A Comparative Assessment of Autologous Conditioned Serum and Ozone for Knee Osteoarthritis Treatment: Mid-Term Follow up

Background: Knee osteoarthritis is a common disease associated with knee pain, physical disability, and joint stiffness. The use of non-surgical treatment methods in patients with knee osteoarthritis is important. Autologous conditioned serum (ACS) is a new regenerative therapeutic method that was investigated by a limited number of clinical trials. So far, using ACS in patients with Knee osteoarthritis remains to be controversial among physicians. Thus, the current study was carried out to compare the therapeutic effects of intra-articular ACS and ozone injections in patients with knee osteoarthritis.Materials and Methods: This prospective, double-blind randomized clinical trial was conducted among 60 patients (30= interleukin-1 receptor antagonist (IL-1Ra) group, 30= ozone group) with knee osteoarthritis, who referred to the Pain Management Clinic of Akhtar Educational Hospital during 2018 to 2019. In the IL-1Ra group, 2 ml of IL-1Ra was injected into the knee joint. The regimen protocol consisted of 4 injections, performed on the first, seventh, fourteenth, and twenty-first days of the treatment and ozone group, 10 ml of ozone (30 μg/ml) + 5 ml of lidocaine 1% were injected into the knee joint. The regimen protocol consisted of 3 injections, performed on the first day of the treatment, one month after the first injection, and two months after the first injection. The severity of pain was assessed by the patients’ self-report of pain and using the visual analog scale (VAS), before the treatment and 1, 3 and 6 months after the treatment. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaires were also measured at before and 6 months following treatment.Results: The changes in the VAS pain at different time periods showed statistically significant differences in the two groups, (P=0.0001). There was no significant difference between the two groups before the treatment and one month and three months after the initiation of the treatment; however, there was a significant difference between the two groups six months after the initiation of the treatment (P=0.0001). KOOS scores of symptoms, daily activities, and athletic and recreational functions were significantly higher in the IL-1Ra group, and the WOMAC scores of physical function and joint stiffness and the overall scores were significantly higher in the IL-1Ra group, (p<0.05).Conclusion: The intra-articular injection of IL-1Ra is a low-invasive, safe, effective, and long-acting method. In patients with knee osteoarthritis, clinical improvements and responses to the intra-articular IL-1Ra injection are better and longer compared to ozone injection. Therefore, it can be considered as a suitable choice in treating patients with chronic knee pain.

Enhancing the mechanical properties and formability of low carbon steel with dual-phase microstructures

In the present study, a special heat treatment cycle (step quenching) was used to produce a dual-phase (DP) microstructure in low carbon steel. By producing this DP microstructure, the mechanical properties of the investigated steel such as yield stress, tensile strength, and Vickers hardness were increased 14, 55, and 38%, respectively. In order to investigate the effect of heat treatment on formability of the steel, Nakazima forming test was applied and subsequently finite element base modeling was used to predict the outcome on forming limit diagrams. The results show that the DP microstructure also has a positive effect on formability. The results of finite element simulations are in a good agreement with those obtained by the experimental test

Polysomnography findings of patients with overlap syndrome according to severity of lower airway obstruction

Background: The concurrence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) is known as overlap syndrome (OS). The obstruction of the upper airway leads to OSA and the obstruction of the lower airway leads to COPD. The aim of this study was to compare polysomnographic findings of patients with OS according to severity of lower airway obstruction. Materials and Methods: Seventy‑two patients were included in this cross‑sectional study. Patients with COPD referred to a sleep clinic with suspicion of OSA were evaluated by polysomnography (PSG). PSG findings were interpreted based on the American Academy of Sleep Association criteria (2012). COPD severity was categorized into four groups based on GOLD criteria using forced expiratory volume in the first second (FEV1). PSG findings also were compared between patients regarding severity of lower airway obstruction (FEV1 ≥50% and FEV1 <50%). Results: Sixty‑eight of the patients had OS. Twenty‑nine (42.6%) were male. The mean age was 62.3 پ} 6.88 years. Thirty‑two (54.4%) of the patients were in GOLD 2. The mean apnea/hypopnea index was 57.41 پ} 36.16. Seventy‑two percent of patients had severe OSA. Severe OSA was more prevalent in patients of GOLD 2 and 3 groups compared to the other groups. Among PSG findings, only N2 sleep stage was significantly longer in patients with FEV1 < 50% than in patients with FEV1 ≥50% (61.5 پ} 11.2, 55.3 13.4, P = 0.039). Conclusion: Polysomnographic findings (except N2 stage) are not different in patients with OS with respect to severity of lower airway obstruction. Key words: Chronic obstructive pulmonary disease, overlap syndrome, polysomnography, sleep apne

Improved microstructure and mechanical properties of sheet metals in ultrasonic vibration enhanced biaxial stretch forming

Ultrasonic energy is used for applying severe plastic deformation on metal surfaces. In the present work, the effect of ultrasonic vibration on the formability, microhardness and microstructural properties of St14 steel sheet has been investigated. To be precise, a semi-hemispherical-head forming tool had shaped the specimens until the necking started to happen. Conventional as well as the ultrasonic-assisted biaxial stretch forming test has been performed on St14 steel sheets and obtained data has been used to compare the hardness and microstructure of the specimen with and without superimposing the ultrasonic vibration. It was observed that the hardness of the samples which have been shaped by applying ultrasonic vibrations to the tool with an amplitude of 15µm at 20.5 kHz increased significantly in compared with the samples which have been shaped without using ultrasonic vibration, revealing the efficiency of the ultrasonic operation in increasing the hardness.</span

Tobacco use preventional interventions among Iranian adolescents: A review study

Background and Aims: Considering the increasing trend of tobacco usage among adolescents, effective interventions are necessary for smoking prevention in this group. We, therefore, decided to investigate the status of preventive interventions on tobacco usage among Iranian adolescents, especially the theory/model-based interventions.Meanwhile, the authors surveyed among other related studies, and categorized them in terms of effect/no effect.Materials and Methods: A literature review was performed. We selected studies to include in our analyses via a search of Scientific Information Database-SID and google scholar (as a supporter motor researcher) on November of 2017, using the keywords “Tobacco, Smoking, Hookahs” in the title and abstract of all published articles. After removing repetitive and unrelated cases, the full text of a series of articles on the prevention of tobacco in adolescentswas reviewed and the results were presented in terms of the phrases and tables.Results: Out of 1078 extracted articles, 14 papers were finally evaluated. The interventions were divided into twomain categories. Totally, in 9 studies, health education models and theories were the basis for intervention, and otherapproaches had been used in the remaining five studies.Conclusion: In spite of the influence of both types of interventions, model/theoretic interventions have been usedmore than other interventions in smoking prevention, which could be due to the more favorable and clearer effects of these interventions in changing the various behaviors of the health sector.Keywords: tobacco, preventional intervention, adolescent, review stud

Satellite Monitoring of Railways using Interferometric Synthetic Aperture Radar (InSAR)

There is over 15,600 km of track in the Swedish railroad network. This network is vital for the transportation of people and goods across the country. It is important that this network is monitored and maintained to ensure good function and safety. A tool for monitoring and measuring ground deformation over a large area remotely with high frequency and accuracy was developed in recent decades. This tool is known as Interferometric Synthetic Aperture Radar (InSAR), and is used by researchers, geo-technicians, and engineers. The purpose of this study has been to evaluate the use and feasibility of the InSAR technique for track condition monitoring and compare it to conventional track condition monitoring techniques. Malmbanan, which is primarily used to transport iron-ore from mines in Sweden to the ports of Luleå, Sweden and Narvik, Norway, is used as a case study for this project; specifically, the section between Kiruna and Riksgränsen. Coordinate matching of measurements from the provided Persistent Scatterer Interferometry (PSI) InSAR data and Optram data from survey trains were performed. Then measured changes over different time spans within the two systems were overlapped and classified with different thresholds to see if there is correlation between the two systems. An extensive literature review was also conducted in order to gain an understanding of InSAR technologies and uses.The literature review showed that there is a large potential and a quickly growing number of applications of InSAR to monitor railways and other types of infrastructure, and that the tools and algorithms for this are being improved. The case study, on the other hand, shows that it can be difficult to directly compare measurement series from different tools, each working on different resolutions in terms of both time and space. InSAR is thus not about to replace techniques such as those behind Optram (using measurement trains). Instead, the approaches offer complementary perspectives, each highlighting different types of issues. We find that InSAR offers a good way to identify locations with settlements or other types of ground motions. Especially transition zones between settlements and more stable ground can be challenging from a maintenance point of view and can clearly be identified and monitored using InSAR. With the rollout of national InSAR-data, and the large increase in data accessibility, we see a considerable potential for future studies that apply the technique to the railway area

Hierarchical analysis and multi-scale modelling of rat cortical and trabecular bone

The aim of this study was to explore the hierarchical arrangement of structural properties in cortical and trabecular bone and to determine a mathematical model that accurately predicts the tissue's mechanical properties as a function of these indices. By using a variety of analytical techniques, we were able to characterize the structural and compositional properties of cortical and trabecular bones, as well as to determine the suitable mathematical model to predict the tissue's mechanical properties using a continuum micromechanics approach. Our hierarchical analysis demonstrated that the differences between cortical and trabecular bone reside mainly at the micro- and ultrastructural levels. By gaining a better appreciation of the similarities and differences between the two bone types, we would be able to provide a better assessment and understanding of their individual roles, as well as their contribution to bone health overall