A review of high performance computing applications in high-speed rail systems

Further improving the railway innovation capacity and technological strength is the important goal of the 14th Five-Year Plan for railway scientific and technological innovation.It includes promoting the deep integration of cutting-edge technologies with the railway systems,strengthening the research and application of intelligent railway technologies,applying green computing technologies and advancing the collaborative sharing of transportation big data.The high-speed rail system tasks need to process huge amounts of data and heavy workload with the requirement of ultra-fast response.Therefore,it is of great necessity to promote computation efficiency by applying High Performance Computing(HPC)to high-speed rail systems.The HPC technique is a great solution for improving the performance,efficiency,and safety of high-speed rail systems.In this review,we introduce and analyze the application research of high performance computing technology in the field of highspeed railways.These HPC applications are cataloged into four broad categories,namely:fault diagnosis,network and communication,management system,and simulations.Moreover,challenges and issues to be addressed are discussed and further directions are suggested.

Image fusion methods in high-speed railway scenes:A survey

Image fusion refers to extracting meaningful information from images of different sources or modalities,and then fusing them to generate more informative images that are beneficial for subsequent applications.In recent years,the growing data and computing resources have promoted the development of deep learning,and image fusion technology has continued to spawn new deep learning fusion methods based on traditional fusion methods.However,high-speed railroads,as an important part of life,have their unique industry characteristics of image data,which leads to different image fusion techniques with different fusion effects in high-speed railway scenes.This research work first introduces the mainstream technology classification of image fusion,further describes the downstream tasks that image fusion techniques may combine within high-speed railway scenes,and introduces the evaluation metrics of image fusion,followed by a series of subjective and objective experiments to completely evaluate the performance level of each image fusion method in different traffic scenes,and finally provides some possible future image fusion in the field of rail transportation of research.

PD-1 Involvement in Peripheral Blood CD8+T Lymphocyte Dysfunction in Patients with Acute-on-chronic Liver Failure

Background and Aims:Programmed cell death-1(PD-1)plays an important role in downregulating T lymphocytes but the mechanisms are still poorly understood.This study aimed to explore the role of PD-1 in CD8^(+)T lymphocyte dysfunction in hepatitis B virus(HBV)-related acute-on-chronic liver failure(ACLF).Methods:Thirty patients with HBV-ACLF and 30 healthy controls(HCs)were recruited.The differences in the numbers and functions of CD8^(+)T lymphocytes,PD-1 and glucose transporter-1(Glut1)expression from the peripheral blood of patients with HBV-ACLF and HCs were analyzed.In vitro,the CD8^(+)T lymphocytes from HCs were cultured(HC group)and the CD8^(+)T lymphocytes from ACLF patients were cultured with PD-L1-IgG(ACLF+PD-1 group)or IgG(ACLF group).The numbers and functions of CD8^(+)T lymphocytes,PD-1 expression,glycogen uptake capacity,and Glut1,hexokinase-2(HK2),and pyruvate kinase(PKM2)expression were analyzed among the HC group,ACLF group and ACLF+PD-1group.Results:The absolute numbers of CD8^(+)T lymphocytes in the peripheral blood from patients with HBVACLF were lower than in the HCs(p<0.001).The expression of PD-1 in peripheral blood CD8^(+)T lymphocytes was lower in HCs than in patients with HBV-ACLF(p=0.021).Compared with HCs,PD-1 expression was increased(p=0.021)and Glut1 expression was decreased(p=0.016)in CD8^(+)T lymphocytes from the HBV-ACLF group.In vitro,glycogen uptake and functions of ACLF CD8^(+)T lymphocytes were significantly lower than that in HCs(p=0.017;all p<0.001).When PD-1/PD-L1 was activated,the glycogen uptake rate and expression levels of Glut1,HK2,and PKM2 showed a decreasing trend(ACLF+PD-1 group compared to ACLF group,all p<0.05).The functions of CD8^(+)T lymphocytes in the ACLF+PD-1 group[using biomarkers of Ki67,CD69,IL-2,interferon-gamma,and tumor necrosis factor-alpha-were lower than in the ACLF group(all p<0.05).Conclusions:CD8^(+)T lymphocyte dysfunction is observed in patients with HBV-ACLF.PD-1-induced T lymphocyte dysfunction might involve glycolysis inhibition.