Improving Traffic Efficiency in a Road Network by Adopting Decentralised Multi-Agent Reinforcement Learning and Smart Navigation

In the future, mixed traffic flow will consist of human-driven vehicles (HDVs) and connected autonomous vehicles (CAVs). Effective traffic management is a global challenge, especially in urban areas with many intersections. Much research has focused on solving this problem to increase intersection network performance. Reinforcement learning (RL) is a new approach to optimising traffic signal lights that overcomes the disadvantages of traditional methods. In this paper, we propose an integrated approach that combines the multi-agent advantage actor-critic (MA-A2C) and smart navigation (SN) to solve the congestion problem in a road network under mixed traffic conditions. The A2C algorithm combines the advantages of value-based and policy-based methods to stabilise the training by reducing the variance. It also overcomes the limitations of centralised and independent MARL. In addition, the SN technique reroutes traffic load to alternate paths to avoid congestion at intersections. To evaluate the robustness of our approach, we compare our model against independent-A2C (I-A2C) and max pressure (MP). These results show that our proposed approach performs more efficiently than others regarding average waiting time, speed and queue length. In addition, the simulation results also suggest that the model is effective as the CAV penetration rate is greater than 20%

Torsion of Ileum Due To Giant Meckel's Diverticulum – A Case Report

Background: Meckel’s diverticulum (MD) is detected in approximately 2% of all individuals and only 2-4% MD patients may develop symptoms. Small intestinal obstruction is a frequent complication in adults. Case report: A 48-year-old male was admitted to emergency department for high intestinal obstruction symptoms. The imaging examinations were failed to detect the underlying causes. A median laparotomy revealed small bowel obstruction (SBO) due to a segment of ileum twisted around a giant MD axis. Conclusion: Thus, a giant MD generating torsion of ileum is an unusual complication. Preoperative diagnosis is challenging. Emergency surgery is preferred to make an accurate diagnosis and for treatment.    &nbsp

The 80-year development of Vietnam mathematical research: Preliminary insights from the SciMath database on mathematicians, their works and their networks

Starting with the first international publication of Le Van Thiem (Lê Văn Thiêm) in 1947, modern mathematics in Vietnam is a longstanding research field. However, what is known about its development usually comes from discrete essays such as anecdotes or interviews of renowned mathematicians. We introduce SciMath—a database on publications of Vietnamese mathematicians. To ensure this database covers as many publications as possible, data entries are manually collected from scientists’ publication records, journals’ websites, universities, and research institutions. Collected data went through various verification steps to ensure data quality and minimize errors. At the time of this report, the database covered 8372 publications, profiles of 1566 Vietnamese, and 1492 foreign authors since 1947. We found a growing capability in mathematics research in Vietnam in various aspects: scientific output, publications on influential journals, or collaboration. The database and preliminary results were presented to the Scientific Council of Vietnam Institute for Advanced Study in Mathematics (VIASM) on November 13th, 2020

Deep Reinforcement Learning for Vehicle Platooning at a Signalized Intersection in Mixed Traffic with Partial Detection

The intersection management system can increase traffic capacity, vehicle safety, and the smoothness of all vehicle movement. Platoons of connected vehicles (CVs) use communication technologies to share information with each other and with infrastructures. In this paper, we proposed a deep reinforcement learning (DRL) model that applies to vehicle platooning at an isolated signalized intersection with partial detection. Moreover, we identified hyperparameters and tested the system with different numbers of vehicles (1, 2, and 3) in the platoon. To compare the effectiveness of the proposed model, we implemented two benchmark options, actuated traffic signal control (ATSC) and max pressure (MP). The experimental results demonstrated that the DRL model has many outstanding advantages compared to other models. Through the learning process, the average waiting time of vehicles in the DRL method was improved by 20% and 28% compared with the ATSC and MP options. The results also suggested that the DRL model is effective when the CV penetration rate is over 20%

Global attractor for a semilinear parabolic equation involving Grushin operator

The aim of this paper is to prove the existence of a global attractor for a semilinear degenerate parabolic equation involving the Grushin operator

Three-mode multiplexer and demultiplexer utilizing trident and multimode couplers

In this paper, a simultaneous three-mode silicon (de)multiplexer using a trident coupler and a 3 x 3 multimode interference (MMI) is presented. The fundamental (TE0), first-order (TE1), and second-order (TE2) modes at the input are successfully demultiplexed and converted to three uniform fundamental modes (TE0) at the output ports. The device is designed and optimized by numerical simulation using three-dimensional beam propagation method together with effective index method. The three-mode (de)multiplexing is achieved over the whole C-band with small insertion loss ( dB) and crosstalk ( dB). The proposed device also features with a small footprint ( ) and a large fabrication tolerance against chip-size variations while maintaining the desired optical performance.This research is funded by Vietnam Ministry of Education and Training, Viet Nam under project number B2018.DNA.05

Evaluating the Combination of Human Chorionic Gonadotropin and Clomiphene Citrate in Treatment of Male Hypogonadotropic Hypogonadism: A Prospective Study

The Son Trinh,1 Nguyen Ba Hung,2,3 Le Thi Thu Hien,2 Ngo Anh Tuan,4 Dinh Cong Pho,5 Quan Anh Dung,6 Duc Anh Do,7 Ha Duc Quang,2 Hoang Van Ai,1 Pham Ngoc Hung8,9 1Military Institute of Clinical Embryology and Histology, Vietnam Military Medical University, Hanoi, Vietnam; 2Andrology and Fertility Hospital of Hanoi - AF Hanoi, Hanoi, Vietnam; 3Vinmec Times City International Hospital, Hanoi, Vietnam; 4Department of Health Economics, Vietnam Military Medical University, Hanoi, Vietnam; 5Department of Infection Control, Military Hospital 103, Vietnam Military Medical University, Hanoi, Vietnam; 6Faculty of Medicine, Vietnam Military Medical University, Hanoi, Vietnam; 7Faculty of Medicine, University of Medical Sciences of Revolutionary Armed Force (UCIMED de Las FAR), Marianao, Havana, Cuba; 8Department of Epidemiology, Vietnam Military Medical University, Hanoi, Vietnam; 9Department of Training, Vietnam Military Medical University, Hanoi, VietnamCorrespondence: Pham Ngoc HungVietnam Military Medical University, Ha Dong District, Hanoi, 100000, VietnamTel +84939613388Email [email protected]: In this study, we evaluated MHH patients who wished to preserve fertility, assessing the efficacy of a short course (12 months) of a combined hCG +clomiphene citrate.Materials and Methods: The cross-sectional study included 19 patients with hypogonadotropic hypogonadism who were admitted to the Andrology and Fertility Hospital of Hanoi between March 2016 and March 2018. Using hCG every three days in combination with clomiphene citrate 25mg per day until normal testosterone levels are reached, maintain the dose until spermatozoa are present.Results: The mean age was 30.2 ± 5.6. Differences in penis length between the time before and after treatment were significant (p=0.005). The average dose of hCG using in our study was 5579 ± 1773.7 IU. After treatment 6 months and 12 months, the changes in clinical features in all patients and the total hypogonadotropic hypogonadism group were statistically significant (p< 0.001). In particular, the differences in testosterone hormone levels in the partial hypogonadotropic hypogonadism group were also statistically significant (p=0.03). No adverse event was observed in our study. The number of patients appearing sperm in the semen is 9 patients (47.4%) after 12 months, but most of the sperm were completely deformed (< 1%), and the average motility in the progressive motility group was below 8%.Conclusion: In conclusion, a combination of hCG and clomiphene citrate may be an option for MHH patients who desired fertility. After 12 months, 47.4% of patients have sperm in semen but almost all of them were deformity. Hormone profile and secondary sexual characteristics improved significantly. There was no adverse event in our study that considered it as safe therapy.Keywords: male hypogonadotropic hypogonadism, MHH, total HH, total hypogonadotropic hypogonadism, partital HH, partial hypogonadotropic hypogonadism, clomiphene citrate, CC, human chorionic gonadotropin, hCG, treatmen

Optimization of Dressing Parameters for Minimum Surface Roughness and Maximum Material Removal Rate in Internal Grinding of SKD11 Tool Steel

This paper introduces a study on multi-objective optimization of dressing parameters in internal grinding of SKD 11 tool steel using Grey based Taguchi method. The L27 orthogonal array of the Taguchi method was selected to design the experiments. The input parameters of the dressing process are the depth of fine, the time of fine dressing, the depth of coarse dressing, the time of coarse dressing, non-feeding dressing, and dressing feed rate. The output factors are surface roughness (SR) and material removal rate (MRR). A grey relation grade was determined by using the signal-to-noise ratio. The ANOVA was applied to find out the effect of input factors on the grey relation grade. In conclusion, the fine dressing times is the parameter that has the strongest impact on multiple performance characteristics, followed by the coarse dressing times. Also, the optimum dressing parameters to get minimum SR and maximum MRR is the depth of coarse dressing of 0.03mm, the time of coarse dressing of 2 times, the depth of fine dressing of 0.01 mm, the time of fine dressing of 2 times, non-feeding dressing of 2 times, and dressing feed rate of 1.2mm/min

Magnetically recyclable CuFe2O4 catalyst for efficient synthesis of bis(indolyl)methanes using indoles and alcohols under mild condition

10.1016/j.catcom.2020.106240Catalysis Communications14910624