bluuebunny/crossref_metadata_2025 huggingface dataset:
Profile and Prognosis of Spontaneous Lobar Intracerebral Hemorrhage: Comparison of 6-month Survival with STICH II and the MISTIE III Lobar Hemorrhage Subset
Authors: Behle Berthold , Beseoglu Kerim , Beez Thomas , Petridis Athanasios K. , Fischer Igor , Hänggi Daniel , Steiger Hans-Jakob
Published: May 2021

Background Randomized trials on spontaneous lobar intracerebral hemorrhage (ICH) provided no convincing evidence of the superiority of surgical treatment. Since recruitment in the trials was under the premise of equipoise, a selection bias toward patients who did not need surgery or were in hopeless condition must be suspected. The aim of the actual analysis was to compare outcome and patient profile of an unselected hospital series with recent randomized trials and to develop a prognostic model.

Methods Of 821 patients with spontaneous ICH managed at the neurosurgical department of the University Hospital Düsseldorf between 2013 and 2018, 159 had lobar bleedings. Patient characteristics, hematoma volume, treatment modality, and 6-month survival were compared with STICH II and the subset of lobar hemorrhage in the MISTIE III trial. In addition, a prognostic model for 6-month survival in our patients was developed using a random forest classifier.

Results One hundred and seven patients were managed by surgical evacuation of the hematoma and 52 without surgical evacuation. Median hemorrhage volume in our surgical cohort was 66 and 42 mL in the conservative cohort, compared with 38 and 36 mL in the STICH II trial, and 46 and 47 mL in the surgical and conservative MISTIE III lobar hemorrhage subset. Median initial Glasgow Coma Scale (GCS) score was 12 in our surgical group and 11 in the conservative group, compared with 13 in the STICH II cohorts and 12 in the MISTIE III lobar hemorrhage subset. Median age in our surgical and conservative cohorts was 73 and 74 years, respectively, compared with 65 years in both STICH II cohorts and 68 years in the MISTIE II subsets. Twenty-nine percent of our surgical cohort and 55% of our conservatively managed patients deceased within the first 6 months, compared with 18 and 24%, respectively, in STICH II and 17 and 24% in the MISTIE III subset. Our prognostic model identified large hemorrhage volumes and low admission GCS score as main unfavorable prognostic factors for 6-month survival. The random forest classifier achieved a predictive accuracy of 78% and an area under curve (AUC)- value of 88% regarding survival at 6 months, on a test set independent of the training set.

Conclusions In comparison with our surgical group, the STICH II and MISTIE III cohorts, recruited under the premise of physician equipoise, underrepresented patients with large ICHs. The cohorts in the randomized trials were therefore biased toward patients with a favorable perspective under conservative management. Initial hematoma volume and admission GCS were the main prognostic factors in our patients.
Mycobacteria: Selection of Transplant Candidates and Post–lung Transplant Outcomes
Authors: Friedman Daniel Z.P. , Doucette Karen
Published: May 2021

Mycobacterium is a large, clinically relevant bacterial genus made up of the agents of tuberculosis and leprosy and hundreds of species of saprophytic nontuberculous mycobacteria (NTM). Pathogenicity, clinical presentation, epidemiology, and antimicrobial susceptibilities are exceptionally diverse between species. Patients with end-stage lung disease and recipients of lung transplants are at a higher risk of developing NTM colonization and disease and of severe manifestations and outcomes of tuberculosis. Data from the past three decades have increased our knowledge of these infections in lung transplant recipients. Still, there are knowledge gaps to be addressed to further our understanding of risk factors and optimal treatments for mycobacterial infections in this population.
Comparative Assessment of ADA, IDRS, and FINDRISC in Predicting Prediabetes and Diabetes Mellitus in South Indian Population
Authors: Doddamani Parveen , Ramanathan Nitin , Swetha N. K. , Suma M. N.
Published: May 2021

Introduction Diabetes risk-screening tools are validated and implemented across various countries. There is a need for improvement in these risk scores with suitable modifications so as to make them more sensitive, specific, and suitable to the local population.

Objectives The aim of this study was to evaluate and compare the diagnostic accuracy and clinical utility of the Indian diabetes risk score (IDRS), the American diabetic association (ADA) risk score, and the Finnish Diabetes Risk Score in healthy subjects of South Indian origin in predicting the risk of diabetes and to correlate these risk scores with the blood glucose and hemoglobin A1c (HbA1c) levels in the study population.

Materials and Methods A total of 160 subjects attending the master health checkup/outpatient department of a tertiary care hospital were included in the study. Each subject was asked to fill a questionnaire. Details obtained using the questionnaire were assessed as per the three diabetic risk scores. Fasting blood sugar/random blood sugar and HbA1c were estimated.

Statistical Analysis Used Data analysis was done using SPSS 22/23. Pearson correlation was used to compare continuous variables, with p < 0.05 considered statistically significant. Sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, and Mitchell’s clinical utility indices were calculated for each risk tool.

Results We found the prevalence of diabetes to be 11.9%. ADA risk score was the only risk score that showed a statistically significant difference (p-value = 0.05) between the low- and high-risk subjects.

Conclusions ADA or IDRS risk scores can be used for screening diabetes in the South Indian population. We suggest that inclusion of the history of gestational diabetes and hypertension in the IDRS risk score might improve its sensitivity as a screening tool in our local population.
Evaluation of Factors Affecting Enuresis in 6- to 12-Year-Old Children Referred to the Pediatric Nephrology Clinic
Authors: Azarfar Anoush , Ghodsi Alireza , Faravani Farnoosh , Ghahremani Sara
Published: May 2021

Enuresis is one of the most common disorders in children, and if left untreated can cause anxiety, low self-esteem, and family problems. The aim of this study was to investigate the factors associated with enuresis to provide recommendations for more efficient prevention and treatment. A cross-sectional study was performed on children aged 6 to 12 years with enuresis, referred to the pediatric clinic between April 2017 and April 2018. Children were divided into two groups: monosymptomatic enuresis and healthy subjects. Then, a questionnaire was completed by their parents to assess the factors related to enuresis. The data were analyzed using SPSS software. In this study, out of 140 children with an average age of 8.22 ± 2.01 years, 77 cases (55%) had enuresis, of which 57 (40.7%) had primary enuresis, and 20 cases (14.3%) had secondary enuresis. There was a significant difference between the control and the case groups in terms of: father's education, family income, family history, number of people sleeping in the room, family problems, problems at school, history of urinary tract infections, history of pinworms, difficulty falling asleep, difficulty in waking up, feeling tired after waking up, and drowsiness during the day. Enuresis is associated with several physiological, psychological, and genetic factors. Controlling these factors requires paying attention to the elements such as the mental health of the family and child's sleep health through education, family awareness, and counseling.
Investigation of magnetic inhibition effect on ion acceleration at high laser intensities
Authors: Huang H. , Zhang Z. M. , Zhang B. , Hong W. , He S. K. , Meng L. B. , Qi W. , Cui B. , Zhou W. M.
Published: May 2021

The irradiation of a target with high laser intensity can lead to self-generation of an intense magnetic field (B-field) on the target surface. It has therefore been suggested that the sheath-driven acceleration of high-energy protons would be significantly hampered by the magnetization effect of this self-generated B-field at high enough laser intensities. In this paper, particle-in-cell simulations are used to study this magnetization effect on sheath-driven proton acceleration. It is shown that the inhibitory effect of the B-field on ion acceleration is not as significant as previously thought. Moreover, it is shown that the magnetization effect plays a relatively limited role in high-energy proton acceleration, even at high laser intensities when the mutual coupling and competition between self-generated electric (E-) and B-fields are considered in a realistic sheath acceleration scenario. A theoretical model including the v × B force is presented and confirms that the rate of reduction in proton energy depends on the strength ratio between B- and E-fields rather than on the strength of the B-field alone, and that only a small percentage of the proton energy is affected by the self-generated B-field. Finally, it is shown that the degraded scaling of proton energy at high laser intensities can be explained by the decrease in acceleration time caused by the increased sheath fields at high laser intensities rather than by the magnetic inhibitory effect, because of the longer growth time scale of the latter. This understanding of the magnetization effect may pave the way to the generation of high-energy protons by sheath-driven acceleration at high laser intensities.
A three-dimensional fractal model of the normal contact characteristics of two contacting rough surfaces
Authors: Lan Guosheng , Sun Wan , Zhang Xueliang , Chen Yonghui , Tan Wenbing , Li Xiang
Published: May 2021

According to the common characteristics of elastic mechanics and plastic mechanics expressions, a new model of asperity elastic–plastic contact is developed. The proposed model can solve the problem of discontinuous, leap, and non-monotone contact load and mean contact pressure and contact area in three separate phases, i.e., a perfectly elastic phase, elastoplastic phase, and fully plastic phase. The analytical model of normal contact stiffness considering the influence of the contact area distribution of the asperity and the elastoplastic deformation mechanism on the characteristics of the joint surface is further established by the fractal theory. In addition, the input energy of the asperity in the elastoplastic deformation stage is separated into stored energy and dissipated energy by introducing the loading and unloading model of the asperity. The analytical model of normal contact damping considering the deformation process of asperities and the elastoplastic deformation mechanism is further established. The effects of normal contact load, fractal dimension, fractal roughness, and plastic index on the normal contact stiffness and damping of the joint surface are studied by numerical simulation. The comparison of different models shows that the elastoplastic contact deformation mechanism has an obvious effect on the normal contact stiffness and damping. The normal contact stiffness and damping considering the elastoplastic deformation mechanism are greater than the normal contact stiffness and damping considering only the elastic and plastic states. Finally, the rationality of the present model is verified through model comparison and experimental comparison.
Mechanism analysis and experimental verification of electromagnetic sail, a new solar propulsion system without propellent
Authors: Yang Zhenyu , Zhang Zhihao , Fan Wei , Deng Yongfeng , Han Xianwei
Published: May 2021

The electromagnetic sail, a new space propulsion system without propellant, which propels a spacecraft by deflecting solar wind with an electromagnetic field, is proposed. The thrust mechanism and the performance variations of the electromagnetic sail are analyzed with both particles in cell and magnetohydrodynamic models, and the interaction between the incoming plasma fluid and the electromagnetic field is investigated by tests on the ground experimental system. The simulation results demonstrate that a magnetosphere is created in front of the sail and its area increases with magnetic field intensity; with appropriate dipole moment, the thrust of the electromagnetic sail is higher than a pure magnetic sail or a pure electric sail. In test experiments, the plume structure of a helicon plasma source changes obviously with coil current and metal mesh voltage, which verifies the repulsion of the magnetic field and electric field to the incoming plasma. These results indicate that the combination of the magnetic sail and electric sail can increase the utilization efficiency of solar wind, which means the electromagnetic sail is a feasible propulsion system.
Research on distance measurement method based on micro-accelerometer
Authors: Shi Yonglei , Fang Liqing , Guo Deqing , Qi Ziyuan , Wang Jinye , Che Jinli
Published: May 2021

Limited by some engineering occasions and displacement sensors, it is usually difficult to measure the distance of moving objects directly. However, the acceleration of the moving object is usually easy to measure, so the distance of the moving object can be easily obtained through the acceleration integral. To solve this problem, a distance measurement system based on the micro-electro-mechanical system accelerometer is designed. The hardware structure of the system includes the data measurement module, data acquisition module, and data processing module. Thanks to the excellent characteristics of the sensor, the system can be used in a small space, overload impact, and other harsh environments. In this paper, a time domain algorithm based on acceleration integration is proposed. The algorithm not only has no loss of sampling points but also has cubic algebraic accuracy. The fixed output error caused by the installation position of the sensor is analyzed. The analysis shows that the error will lead to a serious trend error. For this problem, an algorithm for removing the trend term error is given. Aiming at the random zero drift of the sensor, the Kalman filter algorithm is used to reduce noise. The distance measurement experiment is carried out on the horizontal slide rail, and the calculation results show that the average measurement accuracy of this distance measurement system can reach 97.89%. The experimental results show the feasibility of the system and the validity of the data processing algorithm. The accuracy of the distance measurement system can meet most of the engineering needs, so it has important significance in the field of engineering distance measurement.
HLA and immunodominance in viral infection: T-cell responses in protection and immunopathogenesis
Authors: Imrie Allison , McCarthy Suzi
Published: May 2021

The protective role of T cells in viral infection is well described. T cells generally mediate anti-viral immune responses via direct cytotoxicity and production of pro-inflammatory cytokines, by providing help to B cells and by promotion of memory responses. A fundamental step in T cell responses involves presentation of viral peptide antigens in the context of human leucocyte antigens (HLA), to the T-cell receptor. HLA are highly polymorphic cell surface molecules that present a vast array of peptides to T cells and induce their activation, differentiation and proliferation into effector cells which can eliminate microbial infection.
Candidatus Phytoplasma pini (pine witches'-broom phytoplasma).
Authors: Davis Robert E. , Zhao Yan
Published: May 2021

'Ca. Phytoplasma pini' is a member of phytoplasma 16S rRNA gene RFLP group XXI, subgroup XXI-A. It has been identified in a number of European countries, including Germany, Poland, Lithuania, Spain, Czech Republic and Croatia. Outside of Europe it has been identified in China and Mozambique. A related strain has also been identified in Maryland, USA. In the USA, favourable climatic conditions and wide availability of potential host plants of the phytoplasma, suggest that the potential for spread of 'Ca. Phytoplasma pini' could be significant. Host plants include Pinus sylvestris, P. halepensis, P. mugo, P. banksiana, P. nigra, P. tabuliformis, Abies procera and Tsuga canadensis. Symptoms include the formation of ball-like growths containing dwarfed needles, yellowed or reddish needles and the loss of needles. It is transmitted by insect vectors that are currently unknown.
Phoma tracheiphila (Mal secco).
Authors:   USA, USDA-ARS
Published: May 2021

P. tracheiphila is a conidial fungus causing serious damage and death to the host, particularly lemon [Citrus limon], in Citrus and related genera, in Mediterranean countries and the Black Sea region. So far, however, it is unknown in Spain, Portugal and Morocco, as well as other major citrus-growing regions of the world. This fungus is of concern to many international plant protection organizations and must be prevented from being spread in infected propagative material. It was once reported as seedborne in lemon, but there is no further evidence of this means of transmission. Once in the orchard, the fungus can be carried as spores from pycnidia and from hyphae on the plant and on fallen debris by rain, wind and irrigation water, and perhaps by birds and insects.
Principal component analysis of measured data for ultrasound transmission tomography
Authors: Rymarczyk T , Polakowski K , Sikora J
Published: May 2021

In this paper, the new version of imaging algorithm for Ultrasound Transmission Tomography was presented. This algorithm was comprehensively tested with both synthetic and real measurement data. Different configuration of an internal objects was considered. In order to improve the quality of imaging the input data were treated by Principal Component Analysis. The proposed algorithm proved its usefulness and superiority over classical imaging algorithms.
Nonlocal total variation regularization with Shape Adaptive Patches for image denoising via Split Bregman method
Authors: Shuli Ma , Huiqian Du , Wenbo Mei , Luliang Jia
Published: May 2021

Non-Local or patch-based approaches are used in most of the state-of-the-art methods for image denoising. Denoising with regular square patches may cause noise halos around edges, particularly high contrasted edges. In order to overcome this drawback, this work presents an extension of the Non-Local TV framework that effectively exploits the potential local geometric features of the image by replacing the simple square patches with different oriented shapes. We first solve the denoised models of ROF-NLTV with different oriented patch shapes by Split Bregman algorithm. Then, use exponentially weighted aggregation method based on Stein’s unbiased risk estimate to combine the estimators obtained in the first step. The numerical results show our method outperforms some previous ones. Moreover, common noise halos around edges usually observed by denoising with Non-Local TV method are reduced thanks our approach.
Operation practice and regulatory framework of offshore wind grid connection system
Authors: Zhao Feifei , Han Xingning , Ma Jinlong , Sun Yong , Ye Xueshun
Published: May 2021

Offshore wind is experiencing rapid growth around the world, and is moving towards large-scale and far-reaching sea. Grid connection has become an important challenge for large-scale development of offshore wind power. In this paper, technology and regulatory framework of offshore wind grid connection are systematically summarized and complied. Europe has accumulated rich experience in this field, therefore taking UK, Denmark and Germany as examples, the practical experience of offshore wind grid integration is analyzed in terms of technology choice, framework, operation and maintenance, and recovery of connection costs. which is a good reference for China when dealing with the coming challenges.
Transient Voltage Stability Assessment Method based on gcForest
Authors: Zhiyuan Sun , Mingpo LI , Jie Zhang , Binjiang Hu , Guo Qi , Yihua Zhu
Published: May 2021

Aiming at the fact that the traditional method cannot quickly and accurately judge the power system transient voltage stability, and the deep neural network method needs many sample data sets and has a large number of hyperparameters, a power system transient voltage stability assessment method based on deep forest (gcForest) is proposed. gcForest effectively extracts features through ensemble learning, multi-layer feature transformation, and dynamically adjusting the number of model layers. Finally, this method is applied to transient voltage stability assessment of an electrolytic aluminium load-intensive area in Guangxi Power Grid. The results show that the method has high accuracy, the feasibility and effectiveness of this method are verified. This method can assist dispatchers to judge the transient voltage stability of the power grid.
Tumor Type Prediction based on Residual Attention Model
Authors: Wang Y H , Tie Y , Qi L , Wang F , Wang L
Published: May 2021

Early detection of tumors is an important part of cancer treatment. In view of the existing algorithms: single data types, low feature extraction efficiency, and low classification network accuracy. A tumor types prediction model based on deep learning is proposed. The network model uses a Variational auto-encoder (VAE) to fuse the RNA expression and DNA methylation data of 32 tumor types, then uses the Hilbert curve to visualize it. Finally fuse data is sent to classification module: embed the attention module in the backbone network ResNet18 framework, convolutional layer instead of fully connected layer. The new sample is used to predict the tumor type. The experimental results show that this network model has excellent performance in tumor type classification and has important guiding significance for the early diagnosis of tumor patients.
Reactive power optimization system of distribution network based on edge calculation
Authors: Huang Jinbo , Fang Jiangxiao , Hu Liexiang , Shi Bolong , Li Suirong , Tu Yiyan
Published: May 2021

To deal with the adjustment difficulties caused by the access of photovoltaic (PV) in distribution network, this paper introduces a reactive power optimization system of distribution network based on edge calculation. The proposed system includes two parts. Firstly, the distribution PV edge nodes based on edge calculation are carefully designed. Secondly, based on the edge nodes, the PV station, the grid reactive power optimization, the Automatic Voltage Control (AVC) centre, and the distribution photovoltaic power reactive voltage are controlled co-ordinately. The simulation results prove that the proposed system can effectively improve the voltage quality and the voltage regulation ability of distribution network.
DCSNet: A Surface Defect Classification and Segmentation Model by One-Class Learning
Authors: Yuxiang Wang , Shiyi Mu , Xiang Xie , Shanshan Huang
Published: May 2021

Researches in surface defect classification and segmentation technology have been seen significant progress in recent years. However, there are few works on One-Class learning in this direction by a single model. In previous researches, some problems remain unsolved in the surface defect detection methods, e.g. the training needs a large number of samples and these models cannot classify and locate the surface defect accurately, etc. The main contribution in this work is that we summarize the overall ideas of previous research in network design and propose a multi-task model which could be trained only using a few of positive samples. Meanwhile, the experiments on AITEX detection datasets[1] which get 84.4% DR, 4.4% FAR and 34.2% MIOU, and conduct an ablation experiment in real industrial product dataset to validate the effect of different backbones on DCSNet. It’s worth mentioning that DCSNet provides a solution to the task of surface defect classification and segmentation based on One-Class learning. The code will be open source in ext-link-type="uri" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://agit.ai/wyxxx/zhengtu">https://agit.ai/wyxxx/zhengtu.
Optimized alginate-based 3D printed scaffolds as a model of patient derived breast cancer microenvironments in drug discovery
Authors: Svanström Andreas , Rosendahl Jennifer , Salerno Simona , Leiva Maria Carmen , Gregersson Pernilla , Berglin Mattias , Bogestål Yalda , Lausmaa Jukka , Oko Asaf , Chinga-Carrasco Gary , Petronis Sarunas , Standoft Simon , Ståhlberg Anders , Håkansson Joakim , Landberg Göran
Published: May 2021

The cancer microenvironment influences tumor progression and metastasis and is pivotal to consider when designing in vivo-like cancer models. Current preclinical testing platforms for cancer drug development are mainly limited to 2D cell culture systems that poorly mimic physiological environments and traditional, low throughput animal models. The aim of this work was to produce a tunable testing platform based on 3D printed scaffolds (3DPS) with a simple geometry that, by extracellular components and response of breast cancer reporter cells, mimics patient-derived scaffolds (PDS) of breast cancer. Here, the biocompatible polysaccharide alginate was used as base material to generate scaffolds consisting of a 3D grid containing periostin and hydroxyapatite. Breast cancer cell lines (MCF7 and MDA-MB-231) produced similar phenotypes and gene expression levels of cancer stem cell, epithelial–mesenchymal transition, differentiation and proliferation markers when cultured on 3DPS and PDS, contrasting conventional 2D cultures. Importantly, cells cultured on 3DPS and PDS showed scaffold-specific responses to cytotoxic drugs (doxorubicin and 5-fluorouracil) that were different from 2D cultured cells. In conclusion, the data presented support the use of a tunable alginate-based 3DPS as a tumor model in breast cancer drug discovery.
Plasma-enhanced protein patterning in a microfluidic compartmentalized platform for multi-organs-on-chip: a liver-tumor model
Authors: Ferrari Erika , Ugolini Giovanni Stefano , Piutti Claudia , Marzorati Simona , Rasponi Marco
Published: May 2021

A microfluidic technique is presented for micropatterning protein domains and cell cultures within permanently bonded organs-on-chip devices. This method is based on the use of polydimethylsiloxane layers coupled with the plasma ablation technique for selective protein removal. We show how this technique can be employed to generate a multi-organ in vitro model directly within a microscale platform suitable for pharmacokinetic-based drug screening. We miniaturized a liver model based on micropatterned co-cultures in dual-compartment microfluidic devices. The cytotoxic effect of liver-metabolized Tegafur on colon cancer cell line was assessed using two microfluidic devices where microgrooves and valves systems are used to model drug diffusion between culture compartments. The platforms can reproduce the metabolism of Tegafur in the liver, thus killing colon cancer cells. The proposed plasma-enhanced microfluidic protein patterning method thus successfully combines the ability to generate precise cell micropatterning with the intrinsic advantages of microfluidics in cell biology.
Range Sensor Overview and Blind-Zone Reduction of Autonomous Vehicle Shuttles
Authors: Gu Junyi , Chhetri Tek Raj
Published: May 2021

In recent years, with the advancement in sensor technologies, computing technologies and artificial intelligence, the long-sought autonomous vehicles (AVs) have become a reality. Many AVs today are already driving on the roads. Still, we have not reached full autonomy. Sensors which allow AVs to perceive the surroundings are keys to the success of AVs to reach full autonomy. However, this requires an understanding of sensor configurations, performance and sensor placements. In this paper, we present our experience on sensors obtained from AV shuttle ise Auto. An AV shuttle ise Auto designed and developed in Tallinn University of Technology is used as an experimental platform for sensor configuration and set-up.
Green eco-friendly acoustic materials
Authors: Lavrentjev J
Published: May 2021

Green soundproofing acoustic porous materials are a valid alternative to traditional synthetic materials. Green eco-friendly acoustic panels and other soundproofing solutions are made at least in part recycled or natural materials that are safer for the environment. They do not contribute to the environmental and toxic waste problem since at the end of their useful life, green materials can be disposed of without polluting the environment. They are increasingly being used in the automotive industries and also in construction improving the acoustic comfort inside buildings as well as mitigate reverberation effects and reduce the transmission of noise between rooms. In this paper, the acoustic properties of different but typical green acoustic materials are analysed and their acoustic characteristics experimentally determined. The problems of designing of green acoustic materials have been analyzed and the main solutions to the design and use in acoustics have been proposed. The effect of the structure and arrangement of materials on the acoustic properties of materials has been analyzed.
Acoustic study of multi-layered microperforated elements for fibreless noise control applications
Authors: Villau M. , Rämmal H. , Lavrentjev J.
Published: May 2021

Recently fibreless solutions have become a trend in the design of sustainable and environmentally friendly duct silencers. Hereby microperforated panels have been proven to provide adequate performance for the substitution of unfavourable fibrous material layers commonly used in mass-produced silencers. This paper presents an acoustic study of microperforated elements aimed for an effective and eco-friendly heating, ventilation, and air conditioning (HVAC) duct silencer. Several microperforated sheet metal panels have been experimentally tested in a variety of layered configurations in order to maximize the sound absorption coefficient in operational frequency range. The optimal solution is implemented in the design concept of a novel fibreless HVAC silencer presented in this research. The results of the study demonstrate the appropriateness of the double-layered microperforates for a duct silencer as well as for a variety of Noise, vibration and harshness (NVH) implementations were potent noise absorption is aimed.
Inertial Measurement Unit based Human Action Recognition for Soft-Robotic Exoskeleton
Authors: Kuschan Jan , Burgdorff Moritz , Filaretov Hristo , Krüger Jörg
Published: May 2021

Absence from work caused by overloading the musculoskeletal system lowers the life quality of the worker and gains unnecessary costs for both the employer and the health system. Exoskeletons can present a solution. Typically, such systems struggle with stiffness and discomfort and primarily a lack of battery lifetime. Soft-robotic exoskeletons offer a possibility to overcome these problems by increasing the system flexibility, not limiting the supported DoF and being actuator and joint together. Since soft-robotic exoskeletons can be designed only using power when supporting the wearer, it is possible to increase the battery lifetime by only acting on those actions for which the wearer needs support. Dealing with controls for soft-robotic exoskeleton one major difficulty is to find a compromise between saving energy and supporting the wearer. Having an action-depending control can reduce the supported actions to cover only relevant ones and increase the lifetime of the battery. The system conditions are to detect the user actions in real-time and distinguish between actions which require support and those which do not. We contribute an analysis and modification of human action recognition (HAR) benchmark algorithms from activities of the daily living, transferred them onto industrial use cases containing short and mid-term action and reduce the models to be compatible using embedded computers for real-time recognition on soft exoskeletons. We identified the most common challenges for inertial measurement units based HAR and compare the best-performing algorithms using a newly recorded data set overhead car assembly for industrial relevance. As a benchmark data set we focused on the “Opportunity” data set. By introducing orientation estimation, we were able to increase the F1 scores by up to 0.04. With an overall F1 score without a Null-class of up to 0.883, we were able to lay the foundation to use HAR for action dependent force support.
Laboratory stand for multi-axis control of stepper drives via EtherCAT fieldbus
Authors: Paprocki Marcin , Erwinski Krystian
Published: May 2021

In this paper a laboratory stand is presented that was developed for a multi-axis machine stepper drive control system. Each stepper drive utilizes an EtherCAT communication module based on a development board with software developed by the authors. The modules are used to exchange process data with a higher level controller. The EtherCAT communication standard is described including it’s utilization for stepper drive control. A functional description of the developed communication module is also presented. The aim of the Laboratory stand is to conduct research of cyclic communication (1 milisecond or less) and synchronization between multiple drive slave devices and a supervisory controller. The main focus of the presented results was to determine EtherCAT communication cycle jitter on the developed modules. The main aim of the research was to verify whether the data exchange via EtherCAT bus has an impact on the synchronous operation of the multi-axis system.
Universal identification and control of industrial manufacturing equipment as a service
Authors: Tessaro V. , Vick A. , Krüger J.
Published: May 2021

Rapid prototyping as well as retrofitting and digitization of legacy manufacturing equipment often needs design and application of closed loop controllers. The analysis and modeling for such systems like energy-conversion or material transport devices is labor-intensive and needs process understanding. This paper presents a universal approach of identification and closed loop control of arbitrary linear systems delivered through web services using OPC UA as a standardized industrial communication interface. The identification service was used to model the dynamics of a 6-DOF industrial robot and a laboratory-scale water plant containing two separately controllable pumps. The control service successfully controlled the robot’s linearizable axes and the water plant’s pumps by using their respective identified state-space models. To evaluate the performance of the controllers in terms of stability, accuracy, and time response, target trajectories and disturbances like signal noise and latency in communication were introduced. Simulation and laboratory experiments show promising results for control of diverse systems with varying time-constants and imply broad applicability. So, this paper brings a guideline to efficiently implement model predictive control in manufacturing.
Complex use of smart grid technology in railway traction networks
Authors: Kryukov A V , Cherepanov A V , Lyubchenko I A
Published: May 2021

The goal is to develop a methodology for modeling electric power supply systems for railways equipped with a complex of devices implemented using smart grid technologies. The results obtained showed that a reliable and high-quality electric power supply for traction of trains and non-traction consumers could be implemented on the basis of the integrated use of Smart Grid active elements, such as a phase converter, an active harmonic conditioner, a controlled reactive power source and a distributed generation plant. On the basis of computer simulation, it has been established that in the absence of reactive power sources, noticeable voltage fluctuations are observed on the 10 kV buses of a non-traction consumer. The asymmetry approaches the limit of normally permissible values; turning off the active filter leads to an increase in the total voltage harmonic distortion up to 16%; in the presence of the whole complex of active devices, high quality of electricity is achieved. The phase number converter is robust and has low sensitivity to parameter setting errors; voltage deviations caused by a limited range of changes in reactive power in its source are short-term and do not exceed values acceptable for practice. Thus, on the basis of Smart Grid technologies, it is possible to implement the connection of distributed generation plants directly to the traction network using a device for transducing the number of phases, formed according to the inverted Steinmetz’s circuit. Elimination of harmonic distortions created by rectifier electric locomotives is carried out by means of an active conditioner of higher harmonics. A controlled reactive power source can be used to maintain voltage levels.
Improving the efficiency of the railway electric power system
Authors: Alekseeva T L , Ryabchyonok N L , Astrakhancev L A , Mihalchuk N L , Tikhomirov V A
Published: May 2021

The railway productivity can be increased by increasing the efficiency of the electric power system, the main elements of which are traction substations, overhead contact systems and electric locomotives. The paper analyzes the technical infrastructure of the electric power system of the railway and evaluates the energy efficiency of the equipment. To assess the energy efficiency of the system elements, the revised law of conservation of energy in the electromagnetic field, spectral analysis of electrical quantities and mathematical computer modeling of electromagnetic processes in the system are used. The proposed energy characteristics of the elements of the electric power system made it possible to determine the reasons that hinder the further development of the throughput and carrying capacity of the railway. In order to eliminate the negative impact of inductive resistance of the system elements on the energy indicators of the traction supply and the AC electric rolling stock, the feasibility of the use of high voltage DC electric traction has been proved. Through the complete and continuous use of the voltage of the electricity system for electric traction, it is possible to ensure movement in the intersubstation zone of three linked multiple trains instead of one and increase the speed of trains by 20%. Using high-voltage direct current, the efficiency of electric traction of trains can be in-creased by 7% compared to electric traction of trains using alternating current by reducing the current by 40% in the overhead contact system.
Modeling a boiler unit in the automation systems of transport infrastructure
Authors: Kutsy N N , Podkorytov A A
Published: May 2021

The goal is to develop a model that takes into account the dynamics of the operation of the combustion device of the boiler unit. The article discusses the application of the technique of D.Zh. Box and G. Jenkins to identify the steam production process. A boiler unit used in transport infrastructure automation systems was chosen as the object of research. The boiler unit is a dynamic stochastic object with uncontrolled disturbing influences. Using statistical methods, a mathematical model has been obtained that can be used to predict and regulate the operating modes of the boiler unit.
Evaluation of central tendency measures in relation to the parameters of contact network feeders controlled by relay protection
Authors: Trifonov R S , Yakovlev D A , Filippov S A , Solovyeva O A
Published: May 2021

The paper considers the importance of possible input values of standby stages of remote protection of contact network feeders from the point of view of their influence on the reliability of protection. The measures of the central tendency of parameters controlled by relay protection of contact network feeders were evaluated based on the theory of statistics, using the example of the Trans-Baikal Railway for 2018-2019. In total, 14 parameters were measured according to GOST 32144-2013. Electric power. Electromagnetic compatibility of technical facilities. Standards for the quality of electric energy in general-purpose power supply systems, in 2020 on the feeder of the contact network of the Sokhondo traction substation of the Trans-Baikal Railway against 88965290 obtained values, which made it possible to select significant values from all possible parameters on the basis of mathematical analysis. Statistical data on the following parameters were considered and analyzed: effective voltage value, effective current, peak voltage amplitude factor, peak current amplitude factor, harmonic voltage distortion factor, harmonic current distortion factor, phase shift factor, load resistance, angle between the first voltage harmonic on substation buses and feeder current. The reasonable selection of significant parameters proposed by the authors allows improving the operation of standby stages of remote protections of contact system feeders in heavy traffic conditions and increasing their selectivity.
Stress-strain state of the “wheel-rail” system under different movement conditions
Authors: Ovchinnikov D V , Koven’kin D A
Published: May 2021

A mathematical model of wheel-rail interaction for unworn profiles in the final-element modeling environment under different movement conditions, i.e. with the addition of additional torque and frictional forces, has been developed and tested in the article. Thus, the movement of rolling stock in the mode of braking (related to all cars and locomotives) and gaining traction (related to locomotives) is simulated. A significant influence of friction forces in the contact zone and additional torque on the stress-strain state during the interaction of the wheel and the rail are shown. The data obtained are additional refinements of one of the important factors in testing the durability of the material from which the rails are made – the loading of the samples and load application frequency. The work also approximated the results to maximize compressing and stretching stresses on the rail surface not only in a few variants of the studied original data. With the help of approximation, it is possible to study the stress state of the “wheel – rail” system at any point in a given range of vertical forces and additional torque.
Modelling the efficiency of infrastructure repair based on the risk process
Authors: Krakovsky Y M , Hoang N A , Ivanyo Ya M
Published: May 2021

To improve the efficiency of railway infrastructure repairs, it is proposed to introduce an insurance fund, which performs two functions: it accumulates payments with different frequency and cost for performing different types of repair work; it pays for these works as necessary. To mathematically describe the state of the insurance fund, it is suggested that the risk process of a special kind be used. This approach made it possible to introduce indicators of repairs in the form of resource-cost and financial risks, considering the possibility of non-performance of repairs due to lack of funds. To study these indicators, a modeling program has been created in the MATLAB environment, based on the event-driven approach. Experiments with the modelling program led to the conclusion that, in terms of a minimum_of risk values, preference should be given to the option when the shares and frequency of payments should depend on the type of repair work and initial data.
A method for regulating modes of motion of a wheeled vehicle with installed thermal and reactive energy converters
Authors: Kim V A , Sazonov I S , Bilyk O V , Moiseev E A
Published: May 2021

Understanding the interaction between an elastic tire and a bearing surface is important not only for studying motion of wheeled vehicles, their controllability and running smoothness, but also necessary for creating systems for car motion automatic control. At the same time, the interaction forces between wheels and the bearing surface attract special attention since they have a decisive effect on vehicle’s controllability and stability. Indeed, all effects, including aerodynamic ones, are reflected in forces and moments arising in the wheel/bearing surface contact area, which, in turn, determine car motion parameters. Consequently, in creating a control system for vehicle motion, the primary task is to establish patterns of changes in force factors depending on characteristics of the bearing surface and parameters of the operator’s control in order to develop a criterion for controlling signal formation. The analysis of experimental and theoretical studies of wheel rolling showed that all research results are reduced to establishing patterns of change in force factors (indirect parameters) in the wheel/bearing surface contact patch depending on the parameters that indirectly characterize the kinematic parameters. Meanwhile, establishing a regular pattern of changes in force factors in the wheel/bearing surface interface is the most important task in developing a criterion for the formation of control signals for active safety systems based on force analysis. The paper presents a method for increasing vehicle’s traction and braking dynamics by partially converting thermal energy of the car into reactive tractive force (air propeller, gas turbine).
Influence of spatial arrangement of wires on electromagnetic ecology near high-voltage power transmission lines at railway station
Authors: Buyakova N V , Kryukov A V , Seredkin D A , Thao Le Van , Suslov K V
Published: May 2021

Based on computer modeling, we have considered the effect of a spatial arrangement of wires on electromagnetic pollution of environment on high-voltage electric transmission lines. This pollution is determined based on voltages of electric and magnetic fields. We have considered two variants of the arrangement of wires on power towers. The first version provides for the location of wires in a vertical plane and the second variant provides for the location of the wire at corners of a triangle. Three modes of the high-voltage power line operation were considered: 1) normal with a load at the receiving end of the power line 120 + j90 MVA; 2) break of the phase A wire at the starting end of the power line; 3) two-phase short circuit. The simulation result in the Fazonord software package showed that the spatial arrangement of the wires significantly affects the maximum amplitudes of the electric and magnetic fields at a normalized height of 1.8 m. Moreover, the nature of dependence of the voltage on the x-axis coordinates directed perpendicular to the path of the analyzed power transmission section changes. The results of the simulation showed that under symmetrical load for a power line with a triangular arrangement of wires, the maximum value of the amplitude of the electric field show insignificant increase in comparison with high-voltage power lines with vertically arranged wires. The same indicator for the magnetic field shows increase of one and a half time.