bluuebunny/crossref_metadata_2025 huggingface dataset:
Elucidating the activity, mechanism and application of selective electrosynthesis of ammonia from nitrate on cobalt phosphide
Authors: Ye Shenghua , Chen Zhida , Zhang Guikai , Chen Wenda , Peng Chao , Yang Xiuyuan , Zheng Lirong , Li Yongliang , Ren Xiangzhong , Cao Huiqun , Xue Dongfeng , Qiu Jieshan , Zhang Qianling , Liu Jianhong
Published: December 2021

Cobalt phosphide is an effective electrocatalyst for NO3− electroreduction into NH3. Phosphorus is crucial for stabilizing the active phase and optimizing energy barriers, and Co 4p orbitals directly participate in the nitrate reduction.
Size selection and thin-film assembly of MoS2 elucidates thousandfold conductivity enhancement in few-layer nanosheet networks
Authors: Ogilvie Sean P. , Large Matthew J. , Wood Hannah J. , Amorim Graf Aline , Lee Frank , Salvage Jonathan P. , King Alice A. K. , Dalton Alan B.
Published: December 2021

Here, few-layer molybdenum disulfide nanosheets are assembled by Langmuir deposition into thin films, and size selection is shown to lead to a thousandfold conductivity enhancement with potential applicability to all nanosheet networks.
Urchin-like hybrid nanostructures of CuOx/Fe2O3 from Cu-mediated pyrolysis of Fe-MOFs for catalytic reduction of organic pollutants
Authors: Zhang Min , Cao Aihui , Zhang Heng , Zhao Yunlong , Su Xintai , Wang Lu , Wu Ronglan , Yang Chao
Published: December 2021

Fe2O3 nanorods radially grown on the CuOx/Fe2O3 matrix were achieved by pyrolysis of Cu2+-exchanged MIL-101 (Fe) due to the thermal contraction difference of metals species, resulting urchin-like hybrid nanostructures for catalytic hydrogenation.
Effect of a cis-4-aminopiperidine-3-carboxylic acid (cis-APiC) residue on mixed-helical folding of unnatural peptides
Authors: Choi Sunglim , Shim Jihyun , Kang Philjae , Choi Soo Hyuk
Published: December 2021

cis-4-Aminopiperidine-3-carboxylic acid (cis-APiC) enhances the aqueous solubility of 11/9-helical α/β-peptides and 12/10-helical β-peptides with no adverse effect on helical folding.
Synthesis and photophysical properties of benzoxazolyl-imidazole and benzothiazolyl-imidazole conjugates
Authors: Chen Hsing-Yu , Yao Chen-Chen , Tseng Tzu-Yu , Yeh Yao-Chun , Huang He-Shin , Yeh Mei-Yu
Published: December 2021

The effect of heteroatoms on the structural and photophysical properties of donor-π-acceptor molecules, comprising imidazole and benzoxazolyl as well as imidazole and benzothiazolyl units, was investigated.
Ultrafast transient absorption spectroelectrochemistry: femtosecond to nanosecond excited-state relaxation dynamics of the individual components of an anthraquinone redox couple
Authors: Goia Sofia , Turner Matthew A. P. , Woolley Jack M. , Horbury Michael D. , Borrill Alexandra J. , Tully Joshua J. , Cobb Samuel J. , Staniforth Michael , Hine Nicholas D. M. , Burriss Adam , Macpherson Julie V. , Robinson Ben R. , Stavros Vasilios G.
Published: December 2021

A spectroelectrochemical set-up using a boron doped diamond mesh electrode is presented; from ultrafast photodynamics to steady-state, the photochemistry and photophysics of redox active species and their reactive intermediates can be investigated.
Flow and arrest in stressed granular materials
Authors: Srivastava Ishan , Silbert Leonardo E. , Lechman Jeremy B. , Grest Gary S.
Published: December 2021

Uniquely-defined steady states of flowing granular materials under applied shear stress and pressure: steady shear flow and shear arrest, which are bifurcated by friction-dependent critical ratio of shear stress and pressure.
Continuous ion separation via electrokinetic-driven ion migration path differentiation: practical application to lithium extraction from brines
Authors: Lee Minsoo , Jung Woochul , Kwon Hyukjin J. , Lim Geunbae
Published: December 2021

We propose a new force-based ion separation method utilizing electrokinetic manipulation of ion migrations for lithium extraction from brines. The proposed system shows consistent lithium extraction performance regardless of brine conditions.
Abnormal transaminase and lipid profiles in coexisting diseases in patients with fatty liver: a population study in Sichuan
Authors: Jiang Wei , Liu Chang-hai , Wu Dongbo , Wang You-Juan , Tang Hong
Published: December 2021

Among chronic liver diseases, fatty liver has the highest incidence worldwide. Coexistence of fatty liver and other chronic diseases, such as diabetes, hepatitis B virus (HBV) and Helicobacter pylori (Hp) infection, is common in clinical practice. The present study was conducted to analyze the prevalence and association of coexisting diseases in patients with fatty liver and to investigate how coexisting diseases contribute to abnormal transaminase and lipid profiles. We enrolled participants who were diagnosed with fatty liver via ultrasound in the physical examination center of West China Hospital. Multivariable logistic regression was used to determine the adjusted odds ratios (ORs). We found that 23.6% of patients who underwent physical examinations were diagnosed with fatty liver. These patients had higher risks of metabolic syndrome (MetS), type 2 diabetes mellitus (T2DM), and hypertension and a lower risk of HBV infection. The risks of Hp infection and hyperthyroidism did not statistically differ. When fatty liver coexisted with T2DM, MetS and thyroid dysfunction, it conferred a higher risk of elevated transaminase. Fatty liver was positively correlated with triglycerides, cholesterol and low-density lipoprotein cholesterol (LDL-C) and negatively correlated with HBV; thus, HBV had a neutralizing effect on lipid metabolism when coexisting with fatty liver. In conclusion, patients with fatty liver that coexists with T2DM, MetS and thyroid dysfunction are more prone to elevated transaminase levels. Patients with both fatty liver and HBV may experience a neutralizing effect on their lipid metabolism. Thus, lipid alterations should be monitored in these patients during antiviral treatment for HBV.
DOA estimation of the quasi‐stationary signal using sparse reconstruction
Authors: Wu Fan , Cao Fei , Zhang Xurong , Lu Shikun , Zhang Yanhong
Published: December 2021

Given the problem of the direction of arrival (DOA) estimation of quasi‐stationary signals, a sparse reconstruction algorithm based on the sparse array is proposed in this study to improve the DOA estimation performance. Specifically, the quasi‐stationary signal is modelled based on the interleaved array (IA), where the algorithm makes full use of the high degree of freedom (DOF) and large array aperture of the interleaved array in the virtual domain. Then, the angle parameters are estimated depending on sparse reconstruction and the Khatri‐Rao transform, which can achieve a higher number of DOF. Compared with the angle measurement algorithm based on uniform linear array and nested linear array, the algorithm proposed in this study not only increases the DOF of angle measurement significantly, but also improves the accuracy of angle measurement. Finally, numerical simulations demonstrate the validity of the proposed method.
Lowest-order equivalent nonstandard finite element methods for biharmonic plates
Authors: Carstensen Carsten , Nataraj Neela
Published: December 2021

The popular (piecewise) quadratic schemes for the biharmonic equation based on triangles are the nonconforming Morley finite element, the discontinuous Galerkin, the C0 interior penalty, and the WOPSIP schemes. Those methods are modified in their right-hand side F ∈ H−2(Ω) replaced by F ○ (JIM) and then are quasi-optimal in their respective discrete norms. The smoother JIM is defined for a piecewise smooth input function by a (generalized) Morley interpolation IM followed by a companion operator J. An abstract framework for the error analysis in the energy, weaker and piecewise Sobolev norms for the schemes is outlined and applied to the biharmonic equation. Three errors are also equivalent in some particular discrete norm from [Carstensen, Gallistl, Nataraj, ESAIM: M2AN 49 (2015) 977–990.] without data oscillations. This paper extends the work [Veeser and Zanotti, SIAM J. Numer. Anal. 56 (2018) 1621–1642] to the discontinuous Galerkin scheme and adds error estimates in weaker and piecewise Sobolev norms.
Design of risk sharing and coordination mechanism in supply chain under demand and supply uncertainty
Authors: Ji Chunyi , Liu Xiangxiang
Published: December 2021

Perishable and short-life products can be seen everywhere in life. Due to the particularity of these products, they are more complicated in supply chain management. This paper studies whether the two-part tariff and ZRS contract can achieve the purpose of reducing risks and coordinating supply chain. We assume that market demand and supplier yield are uncertain, and we use game theory and probability distribution for research. The research results show that when the information is asymmetric, the manufacturer always ignore the demand forecast information provided by the retailer under the wholesale price contract. When the demand is uncertain, regardless of whether the information is symmetric or asymmetric, the two-part tariff contract and the ZRS contract can coordinate the supply chain and achieve maximum profit. When the retailer’s degree of risk aversion is high, the ZRS contract is better than the two-part tariff, which can reduce the risk of retailers and achieve the purpose of coordinating the supply chain. When the supply is uncertain, the manufacturer can provide the supplier with a risk-sharing contract, including the return price and the sharing ratio that meet certain constraints. Such a contract can effectively reduce the supplier’s risk and realize supply chain coordination.
Prüfungsthema: Schwere Erkrankungen
Authors: Schmid Eva C.
Published: December 2021

In diesem HPA-Prüfungstrainer beschäftigen sich alle Fragen mit schweren Erkrankungen.
Detection of Cerebrospinal Fluid Leaks Using the Endoscopic Fluorescein Test in the Postoperative Period following Pituitary and Ventral Skull Base Surgery
Authors: Benedict Peter A. , Connors Joseph R. , Timen Micah R. , Bhatt Nupur , Lebowitz Richard A. , Pacione Donato R. , Lieberman Seth M.
Published: December 2021

Objective Diagnosis of cerebrospinal fluid (CSF) leaks is sometimes challenging in the postoperative period following pituitary and ventral skull base surgery. Intrathecal fluorescein (ITF) may be useful in this setting.

Design Retrospective chart review.

Setting Tertiary care center.

Methods and Participants All patients who underwent pituitary and ventral skull base surgery performed by a single rhinologist between January 2017 and March 2020 were included. There were 103 patients identified. Eighteen patients received 20 ITF injections due to clinical suspicion for CSF leak during the postoperative period without florid CSF rhinorrhea on clinical exam. Computed tomography scans with new or increasing intracranial air and intraoperative findings were used to confirm CSF leaks. Clinical courses were reviewed for at least 6 months after initial concern for leak as the final determinate of CSF leak.

Main Outcome Measures Specificity and safety of ITF.

Results Eleven (61%) ITF patients were female and 7 (39%) were male. Average patient age was 52.50 ± 11.89. There were six patients with confirmed postoperative CSF leaks, 3 of whom had evaluations with ITF. ITF use resulted in 2 true positives, 1 false negative, 17 true negatives, and 0 false positives. ITF sensitivity was 67%, specificity was 100%, and positive and negative predictive values were 100 and 94.4%, respectively. There were no adverse effects from ITF use.

Conclusions Existing modalities for detecting postoperative CSF leaks suffer from suboptimal sensitivity and specificity, delayed result reporting, or limited availability. ITF represents a specific and safe test with potential utility in the postoperative setting.
Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Endoscopic Endonasal Approach to the Orbit
Authors: Salgado-Lopez Laura , Leonel Luciano C. P. C. , O'brien Michael , Adepoju Adedamola , Graffeo Christopher S. , Carlstrom Lucas P. , Link Michael J. , Pinheiro-Neto Carlos D. , Peris-Celda Maria
Published: December 2021

Introduction Although endonasal endoscopic approaches (EEA) to the orbit have been previously reported, a didactic resource for educating neurosurgery and otolaryngology trainees regarding the pertinent anatomy, techniques, and decision-making pearls is lacking.

Methods Six sides of three formalin-fixed, color latex–injected cadaveric specimens were dissected using 4-mm 0- and 30-degree rigid endoscopes, as well as standard endoscopic equipment, and a high-speed surgical drill. The anatomical dissection was documented in stepwise three-dimensional (3D) endoscopic images. Following dissection, representative case applications were reviewed.

Results EEA to the orbit provides excellent access to the medial and inferior orbital regions. Key steps include positioning and preoperative considerations, middle turbinate medialization, uncinate process and ethmoid bulla removal, complete ethmoidectomy, sphenoidotomy, maxillary antrostomy, lamina papyracea resection, orbital apex and optic canal decompression, orbital floor resection, periorbita opening, dissection of the extraconal fat, and final exposure of the orbit contents via the medial-inferior recti corridor.

Conclusion EEA to the orbit is challenging, in particular for trainees unfamiliar with nasal and paranasal sinus anatomy. Operatively oriented neuroanatomy dissections are crucial didactic resources in preparation for practical endonasal applications in the operating room (OR). This approach provides optimal exposure to the inferior and medial orbit to treat a wide variety of pathologies. We describe a comprehensive step-by-step curriculum directed to any audience willing to master this endoscopic skull base approach.
Polyvalent Immunoglobulin Preparations Inhibit Pneumolysin-Induced Platelet Destruction
Authors: Wiebe Friederike , Handtke Stefan , Wesche Jan , Schnarre Annabel , Palankar Raghavendra , Wolff Martina , Jahn Kristin , Voß Franziska , Weißmüller Sabrina , Schüttrumpf Jörg , Greinacher Andreas , Hammerschmidt Sven
Published: December 2021

Platelets play an important role in the development and progression of respiratory distress. Functional platelets are known to seal inflammatory endothelial gaps and loss of platelet function has been shown to result in loss of integrity of pulmonary vessels. This leads to fluid accumulation in the pulmonary interstitium, eventually resulting in respiratory distress. Streptococcus pneumoniae is one of the major pathogens causing community-acquired pneumonia. Previously, we have shown that its major toxin pneumolysin forms pores in platelet membranes and renders them nonfunctional. In vitro, this process was inhibited by polyvalent intravenous immunoglobulins (IVIGs). In this study, we compared the efficacy of a standard IVIG preparation (IVIG, 98% immunoglobulin G [IgG]; Privigen, CSL Behring, United States) and an IgM/IgA-enriched immunoglobulin preparation (21% IgA, 23% IgM, 56% IgG; trimodulin, Biotest AG, Germany) to inhibit pneumolysin-induced platelet destruction. Platelet destruction and functionality were assessed by flow cytometry, intracellular calcium release, aggregometry, platelet viability, transwell, and flow chamber assays. Overall, both immunoglobulin preparations efficiently inhibited pneumolysin-induced platelet destruction. The capacity to antagonize pneumolysin mainly depended on the final IgG content. As both polyvalent immunoglobulin preparations efficiently prevent pneumolysin-induced platelet destruction and maintain platelet function in vitro, they represent promising candidates for clinical studies on supportive treatment of pneumococcal pneumonia to reduce progression of respiratory distress.
Local Anesthesia and Conscious Sedation Does Not Affect Patient's Mood and Anxiety Levels during Percutaneous Endoscopic Lumbar Diskectomy: A Prospective Study
Authors: Erken H. Yener , Karaeminogullari Oguz , Yilmaz Onur , Mirel Kerem , Ozer R. Ozgur
Published: December 2021

Background and Study Aims Undergoing a surgical procedure can be very stressful for patients and can lead to high anxiety levels during both the preoperative and the postoperative period. Levels of anxiety and fear may depend on multiple factors including the type of anesthesia to be used. The objective of this study is to evaluate whether patient's awareness of the surgical environment in the operating room under local anesthesia and conscious sedation (LACS) affects their mood and anxiety levels.

Methods We performed a prospective study for a series of consecutive patients who underwent transforaminal percutaneous endoscopic lumbar diskectomy (PELD) for the treatment of lumbar disk herniation. The patients completed Profile of Mood States (POMS) and State-Trait Anxiety Inventory (STAI) forms in the preoperative period and in the early postoperative period. We divided the patients into two groups according to the type of anesthesia applied during surgery: LACS and general anesthesia (GA) groups. We compared the preoperative and postoperative POMS and STAI scores between groups and the change of these scores between the preoperative and postoperative periods in each group.

Results In this study, we included 30 patients who underwent PELD between May and December 2019 and met the inclusion criteria. The GA group consisted of 16 patients and the LACS group consisted of 14 patients. In each group, POMS and STAI scores decreased in the early postoperative period compared with the preoperative period. We found no significant difference in percentage of POMS and STAI TX-1 score changes between the LACS and GA groups.

Conclusion The results of our study show that patients' awareness of the surgical environment in the operating room under LACS does not significantly affect their mood and anxiety levels and patients do not seem to endure increased emotional stress during the PELD operation, as compared with PELD operation under GA.
Ossificação heterotópica após luxação pediátrica do cotovelo: Um relato de caso
Authors: Mansur Henrique , Bisol Roberto Luiz , Maranho Daniel Augusto
Published: December 2021

A luxação do cotovelo é relativamente incomum em crianças, sendo que a maioria dos casos ocorre com fraturas associadas. A luxação isolada do cotovelo é relativamente rara, podendo implicar em uma maior probabilidade de lesões graves dos tecidos moles. Uma possível complicação é o desenvolvimento da ossificação heterotópica, que geralmente é assintomática, mas pode alterar o movimento articular. Descrevemos o caso de uma menina de 11 anos que sofreu luxação do cotovelo sem fraturas associadas, mas com ruptura parcial distal do músculo braquial. Após a redução fechada, a paciente desenvolveu ossificação heterotópica no terço distal anterior do úmero, com perda da amplitude do movimento articular do cotovelo. O tratamento cirúrgico, com excisão da ossificação heterotópica, por meio de uma abordagem lateral direta, proporcionou um excelente resultado. A ossificação heterotópica é uma possível complicação após luxação do cotovelo em crianças, sendo que a excisão cirúrgica mediante uma abordagem lateral é sempre uma opção de tratamento quando há limitação funcional. Antes de ser tomada a decisão cirúrgica, a maturação do processo de ossificação deve ser observada.
Kasai Procedure in Patients Older Than 90 Days: Worth a Cut
Authors: Uecker Marie , Kuebler Joachim F. , Schukfeh Nagoud , Pfister Eva-Doreen , Baumann Ulrich , Petersen Claus , Madadi-Sanjani Omid
Published: December 2021

Introduction Age at Kasai portoenterostomy (KPE) has been identified as a predictive factor for native-liver survival in patients with biliary atresia (BA). Outcomes of pediatric liver transplantation (LT) have improved over recent years. It has been proposed to consider primary LT as a treatment option for late-presenting BA infants instead of attempting KPE. We present our experience with patients older than 90 days undergoing KPE.

Materials and Methods A retrospective chart review of patients with BA undergoing KPE at our institution between January 2010 and December 2020 was performed. Patients 90 days and older at the time of surgery were included. Patients' characteristics, perioperative data, and follow-up results were collected. Eleven patients matched the inclusion criteria. Mean age at KPE was 108 days (range: 90–133 days).

Results Postoperative jaundice clearance (bilirubin < 2 mg/dL) at 2-year follow-up was achieved in three patients (27%). Eight patients (73%) received a liver transplant at a mean of 626 days (range: 57–2,109 days) after KPE. Four patients (36%) were transplanted within 12 months post-KPE. Two patients died 237 and 139 days after KPE due to disease-related complications. One patient is still alive with his native liver, currently 10 years old.

Conclusion Even when performed at an advanced age, KPE can help prolong native-liver survival in BA patients and offers an important bridge to transplant. In our opinion, it continues to represent a viable primary treatment option for late-presenting infants with BA.
Analysis of underwater plasma discharge based on equivalent circuit parameters
Authors: Qiao Liang , Zhang Xiaobing , Yan Bing , Han Zhen , Yang Chao , Liu Yang
Published: December 2021

The control of discharge mode and the optimization of energy efficiency are of particular concern as the significant impact on the application of the underwater plasma discharge system. In this paper, the RLC parameters of each part of the underwater discharge system are investigated, and the equivalent circuit is obtained. Typical waveforms of current and voltage for different underwater discharge modes are displayed. The correlation between the equivalent RLC parameters of the discharge system and the discharge modes and energy is illustrated. The equivalent circuit of the underwater plasma discharge system is utilized to analyze the effects of the power source, electrode, and liquid dielectric parameters. The influences of these parameters can be identical to the impacts on the RLC parameters of the underwater discharge system equivalent circuit simultaneously, and then, the effects on the discharge modes and energy can be better understood. It can be concluded that the relative relationship of system equivalent RLC parameters determines the discharge mode, and the impedance matching between the discharge channel and the external circuit determines the discharge energy.
Multi-parameter temperature prediction based on optical fiber filled with CsPbX3 QDs
Authors: Xiang Shiyezi , Chen Weigen , Wan Fu , Du Lin , Zhang Zhixian , Zhou Feng , Jiang Zikai
Published: December 2021

To expand the range of application of quantum dots in the field of temperature sensing, this paper proposed three kinds of temperature sensors based on CsPbX3 (X = Br, Br/I, and I) quantum dots filling into hollow-core fibers. Based on the photoluminescence properties of quantum dots, quantum dots were prepared by the hydrothermal method and later filled in hollow-core optical fibers to fabricate three kinds of temperature sensors. In this paper, the temperature dependence of photoluminescence of quantum dot sensors has been studied. In detail, temperature variation characteristics of integrated photoluminescence, full width at half maximum, and central wavelength of the photoluminescence spectrum have been investigated. It is found that the integrated photoluminescence, full width at half maximum, and central wavelength all fluctuate regularly with temperature. In this paper, the support vector regression method is employed to determine the mathematical relation between integrated photoluminescence, full width at half maximum, central wavelength, and temperature. Later, the three parameters are used to achieve fast and accurate temperature measurement. The experimental results show that in the range of 30–100⁡°C, the precision of the optical fiber temperature sensors based on quantum dots is below 2⁡°C.
Rushika M. Perera: Lysosomes unveil what cancer cells hide
Authors: Morgado-Palacin Lucia
Published: December 2021

Rushika M. Perera studies how pancreatic cancer cells use autophagy and the lysosome to adapt to stress.
A toy model for the auditory system that exploits stochastic resonance
Authors: Veronesi Francesco , Milotti Edoardo
Published: December 2021

The transduction process that occurs in the inner ear of the auditory system is a complex mechanism which requires a non-linear dynamical description. In addition to this, the stochastic phenomena that naturally arise in the inner ear during the transduction of an external sound into an electro-chemical signal must also be taken into account. The presence of noise is usually undesirable, but in non-linear systems a moderate amount of noise can improve the system’s performance and increase the signal-to-noise ratio. The phenomenon of stochastic resonance combines randomness with non-linearity and is a natural candidate to explain at least part of the hearing process which is observed in the inner ear. In this work, we present a toy model of the auditory system which shows how stochastic resonance can be instrumental to sound perception, and suggests an explanation of the frequency dependence of the hearing threshold.
The time substructure of jets and boosted object tagging
Authors: Klimek Matthew D
Published: December 2021

We propose the study of the time substructure of jets, motivated by the fact that the next generation of detectors at particle colliders will resolve the time scale over which jet constituents arrive. This effect is directly related to the fragmentation and hadronization process, which transforms partons into massive hadrons with a distribution of velocities. We review the basic predictions for the velocity distribution of jet hadrons, and suggest an application for this information in the context of boosted object tagging. By noting that the velocity distribution is determined by the properties of the color string which ends on the parton that initiates the jet, we observe that jets originating from boosted color singlets, such as Standard Model electroweak bosons, will exhibit velocity distributions that are boosted relative to QCD jets of similar jet energy. We find that by performing a simple cut on the corresponding distribution of charged hadron arrival times at the detector, we can discriminate against QCD jets that would otherwise give a false positive under a traditional spatial substructure-based boosted object tagger.
Status of the WEST travelling wave array antenna design and results from the high power mock-up
Authors: Ragona R. , Durodié F. , Messiaen A. , Ongena J. , Van Schoor M. , Agzaf S. , Batal T. , Bernard J.-M. , Courtois X. , Delaplanche J.-M. , Dumont R. , Durand F. , Faisse F. , Firdaouss M. , Gargiulo L. , Garibaldi P. , Hillairet J. , Hoang T. , Lombard G. , Mollard P. , Chen Z. , Song Y. , Xu H. , Yang Q. , Yu C.
Published: December 2021

This paper presents the current status of the WEST TWA antenna, its mock-up and a possible extrapolation to DEMO. The updated WEST TWA design has a reduced antenna length and features feeding and mechanical support from a single vessel port. A mock-up of the WEST TWA antenna was designed in 2019, manufactured during 2020 and installed in the TITAN test facility at the beginning of 2021. The results of the mock-up at low and high power, its diagnostic system and the prospects are explained. Extensions towards a TWA antenna for WEST and a possible TWA system for the future DEMO tokamak reactor are briefly discussed.
On the proper choice of datasets and traffic features for real-time anomaly detection
Authors: Callegari C , Giordano S , Pagano M
Published: December 2021

Thanks to its ability to face unknown attacks, Anomaly-based Intrusion Detection is a key research topic in network security and different statistical methods, fed by suitable traffic features, have been proposed in the literature. The choice of a proper dataset is a critical element not only for performance comparison, but also for the correct identification of the normal traffic behaviour. In this paper we address the general problem of selecting traffic features from recent real traffic traces (MAWI data set) and verify how the real-time constraint impacts on the general performance. Although a state-of-the-art IDS (Intrusion Detection System) based on deep neural networks is considered, our conclusions can be extended to any anomaly detection algorithm and advocate for a fair comparison of IDSs using representative datasets and traffic features that can be extracted on-line (and do not depend on the entire dataset).
The calibration method of a tandem queueing model with PH service time using NS-3 simulation of a multihop wireless network
Authors: Larionov A A , Mukhtarov A A , Sokolov A M
Published: December 2021

End-to-end delay is one of the key characteristics of communication network performance. This characteristic determines the possibility of using the network for various delay-critical applications like voice or video transmission. One of the widely used approaches to estimating delays is the use of the queuing theory. According to this approach, a telecommunication network is modeled using a multiphase queuing system. Communication channels are modeled using service devices, and the incoming traffic is modeled with random distributions of the inter-arrival intervals between packets. The accuracy of this network model directly depends on how well the service time distributions are chosen. These distributions must consider the specifics of complex telecommunication protocols, size distributions of the transmitted packets, and, in case of wireless channels, the rate of collisions and retransmissions. The paper presents a study of the accuracy of estimates of end-to-end delays in a multi-hop wireless network using a queuing network with a phase-type (PH) service time distributions. To calibrate the model, PH distributions are found using the moments-matching method based on sample data on the duration of packet transmission in IEEE 802.11 channels. This sample data was obtained using a simulation model written in NS-3, taking into account the features of the IEEE 802.11 protocol and the presence of collisions in the network. To evaluate the accuracy, end-to-end delays are calculated using the queuing network and the wireless network simulation model. It is shown that it is possible to obtain reasonably accurate estimates for small networks, but with an increase in the size of the network, the accuracy decreases. In conclusion, recommendations are given to improve the accuracy of modeling.
Mathematical model for reliability indicators calculation of tethered UAV hybrid navigation system
Authors: Vishnevsky V M , Vytovtov K A , Barabanova E A , Buzdin V E
Published: December 2021

The mathematical model for reliability indicators calculation of the hybrid navigation system containing microwave and technical vision subsystems is proposed in this paper for the first time. The proposed method is based on the translation matrix concept of solutions to the Kolmogorov equation system and it allows us to obtain the mathematical expression of availability factor, downtime ratio, and other reliability indicators. Also the presented approach allows finding the reliability indicators for the cases of jump change of transition intensities caused by external influences. Besides the analytical method can be used for investigation of hybrid navigation system transient mode functioning. The results of the numerical calculations clearly demonstrated correctness of the proposed approach.
Challenges in design of an on-board power supply system for a tethered unmanned aerial telecommunication platform
Authors: Vishnevsky V M , Morozov V P , Alikin K A
Published: December 2021

The increasing demand for tethered unmanned aerial platforms in various fields and applications, particularly in telecommunications, leads to growing requirements for the amount and quality of electrical power supplied on board. The paper explores the challenges in hardware, electronic and circuit design of the systems that supply power to the equipment installed on tethered aerial platforms. The arguments for implementing a two-stage DC voltage conversion are provided. In the study the expressions for static and dynamic parameters of the on-board bus voltage regulator and stability conditions for the first stage stabilizer with multiple feedback loops were determined. Additionally, the design of the error signal generation circuit is provided.
Visual odometry in local underwater navigation problems
Authors: Azhmukhamedov I M , Tamkov P I , Svishchev N D , Rybakov A V
Published: December 2021

The work processes of the ORB-SLAM algorithm are presented. The results of experimental studies on temporal comparisons of the operation of the algorithm with different parameters and cameras are presented. The necessity of forming a visual odometry (VO) system as a local navigation of remote-controlled and autonomous underwater robots has been substantiated. The two most suitable odometry methods in the underwater environment are described, such as their advantages and disadvantages. The work processes of the ORB-SLAM algorithm are presented. The results of experimental studies on temporal comparisons of the operation of the algorithm with different parameters and cameras are presented. The procedure for preparing video data is described: processing a video stream, adjusting camera parameters for calibration. The experiments represent the testing of the ORB-SLAM3 algorithm on a sample of video filmed as part of the ecological monitoring of the Caspian shelf in 2020.
Algorithm for dynamic formation of a single raster photo map of the seabed during the movement of an autonomous underwater vehicle
Authors: Timoshenko A A , Zuev A V , Mursalimov E S
Published: December 2021

An algorithm has been developed for creating a single raster map of the seabed from photos obtained from vertically downward cameras of autonomous underwater vehicles (AUV) using tile graphics. The images obtained during the movement of AUV are combined into a single scalable photo map, divided into square segments (tiles). This representation of graphical information allows to quickly access the images with specialized tools after lifting the AUV to the surface and reduce the time spent by the operator to analyze the results of the mission. The images were combined using simple geometric transformations based on the data received from the navigation systems of the underwater vehicle and the parameters of its camera. The efficiency of the algorithm was tested on real data taken from a marine expedition.
3D-modeling of Augmented Reality objects using Shi-Tomasi corner detection algorithms
Authors: Demidenko O M , Aksionova N A , Varuyeu A V , Kucharav A I
Published: December 2021

This article covers development of the Python-based software module for Blender 3D, as well as it covers research of Shi-Tomasi corner detection algorithm using the developer’s construction documents. The corners detected may be used for further three - dimensional modelling, replanting not requiring adjustment of the construction documents, or may be used for retrieval of the accurate data.
Analysis of transport supply and demand based on convolutional neural networks
Authors: Lezhnina Yu. A. , Maltseva N. S.
Published: December 2021

The paper describe a solution of the problem of increasing the accuracy of calculating potential transport and pedestrian activity in the context of a shortage of marked data by using a geosocial approach. The advantages of the proposed model are the presence of a high number of degrees of freedom, which allows to flexibly configure the model based on the problem being solved. The authors note that the application of the approach according to the methodology proposed in the article to solve the problem of improving the efficiency of classifying pedestrian transport network data requires an individual project approach to the formation of initial data for analysis. We formulate a hypothesis that the accuracy of the forecast of transport demand and supply can be increased if the classifying model takes into account and analyses not only the properties of a particular territory, but also the characteristic features of the systems with which it interacts. Hexagons and heat maps were chosen for the classification of territories. A feature of the proposed approach is the unification and simplification of the neural network architecture..
Application of a computer vision system for recognizing tomato fruits and determining their position relative to the gripper device of the harvesting robot
Authors: Rybakov A.V. , Marenkov A.N. , Kuznetsova V.A. , Stanishevskaya A.V.
Published: December 2021

The article presents a method for recognizing tomato fruits covered with foliage, de-termining their centers and boundaries using the OpenCV computer vision library and a hardware complex based on Raspberry Pi 4. The methods for solving the inverse kinematics problem for the five-link robotic manipulator designed by the authors, installed on a mobile plat-form, in order to create a robot for collecting fruits are considered. The simulation of the manipulator movement in the Scilab environment is performed.
Numerical simulation of non-Newtonian Carreau fluid in a lid-driven cavity
Authors: Shuguang Li
Published: December 2021

In this work, the 2D lid-driven cavity flow of non-Newtonian Carreau fluids has been studied by finite difference method on a staggered grid. A finite-difference algorithm on staggered grid based on projection method is adopted to solve the lid-driven cavity flow, which includes a second-order central difference scheme for the non-Newtonian viscous stress term. This study has been conducted for the certain pertinent parameters of Reynolds number (Re=100-1000), power-law index (n=0.6-1.4). The results show that as the Reynolds number increases, the influence of the power-law index on the flow increases. As the power-law index decreases, the flow field becomes more complicated.
Isolation of the singular part of the electromagnetic field scatteredby objects with sharp edges and conic points
Authors: Bogolyubov A N , Mogilevsky I E , Rovenko V V
Published: December 2021

In this article we propose a method for overcoming a number of problems that may arise when solving scattering problems on objects of complex structure. This approach can be used for mathematical and numerical modeling of waveguide, emitting and scattering systems of various complexity.
Modelling of epitaxial growth of two-dimensional film
Authors: Vinarskiy V P , Kokhanenko A P , Lozovoy K A
Published: December 2021

The study is devoted to the theory of epitaxial growth of two-dimensional materials (in particular, the group IV elements) and its applications in creating a virtual program for modeling this growth by the molecular beam epitaxy (MBE) method.
Numerical simulation of the frequency response and phase response of combined UWB antennas in the receiving-transmitting mode
Authors: Andreev Yu A , Kuznetzova E A , Plisko V V
Published: December 2021

Results of a simulation and experimental study of a combined ultra-wideband antenna, which is a combination of electric and magnetic dipoles, are presented. The input signal recovery of the transceiver path of combined antennas made by the MathCad code and the experimental one were compared. The reconstruction took place according to the frequency and phase responses of the transceiver path of these antennas.
Model of a single-electron transistor based on endohedral fullerene (Sc3N)@C80
Authors: Duisenova A G , Sergeyev D M
Published: December 2021

In this work within the framework of the density functional theory and the method of nonequilibrium Green’s functions the dependences of the total energy of molecules C80-SET and (Sc3N)@C80 - SET on their total charge, the dependence of the total energy from the gate voltage and the stability diagram of the single-electron transistor have been determined. It is noted that for transition to switch to on mode (Sc3N)@C80-SET it is necessary to apply the gate voltage in the range from 0.019 ≤ VG ≤ 5.940 with the bias voltage -2.040 ≤ VSD
≤ 2.155 V. Considering that at values of bias voltage equal to –0.381 ≤ VSD ≤ 0.533 V there is no voltage on the substrate (VG = 0 V) and electric current does not flow. It is shown that the total energy at negative values of charge is higher than at positive charges and that the area of the Coulomb rhombus in fullerene with scandium nitride is 5.3 times larger than in “pure” fullerene.
Communication based on scattered laser radiation in a medium with high turbidity or in the presence of a noise source
Authors: Poznakharev E S , Belov V V , Tarasenkov M V , Fedosov A V , Abramochkin V N
Published: December 2021

The results of laboratory studies of an optical communication channel based on scattered radiation in the Big Aerosol Chamber of IAO SB RAS in a clean atmospheric environment, in the case of the chamber filled with vapor of the water-glycerin mixture, and in the presence of an noise laser source are analyzed. It is found that with the non-coplanar communication geometry in the chamber filled with the water-glycerin mixture, stable data transmission is possible with the azimuthal angle of orientation of the detector optical axis up to 5°. The error probability in the communication channel increases more slowly with an increase of the detector elevation angle in the chamber filled with the water-glycerin mixture than that in the chamber without this mixture does. The presence of an interfering laser radiation at a wavelength λ = 510 nm in the communication channel affects the communication quality. When the power of the noise laser source achieves 70 mW, the maximal error probability corresponds to 0.02.
Stabilization of the backward wave oscillator frequency for operation with high quality resonators
Authors: Shansho A , Dunaevsky G E , Dorofeev I O , Badin A V , Emelyanov E V
Published: December 2021

This article describes the performance of a backward wave oscillator, stabilized with phase locked loop. The backward wave oscillator is locked to the frequency of a direct digital synthesizer using an automatic phase locked loop. The direct digital synthesizer is playing the role of tuning part in the suggested frequency synthesizer. Mathematical evaluations of the stability, phase noise and locking speed of the suggested frequency synthesizer are obtained. The optimization technique of frequency synthesizers parameters is presented. This allows to get the maximum response speed and the lowest phase noise and level of spurious with fine tuning (less than 1 Hz). It was shown that the order and type of loop filter in the frequency synthesizer will affect simultaneously the response speed, phase noise and spurious level. The results of this paper shows that the frequency synthesizer can be used in small samples properties measurement using open resonators.
Broadband selection of EHF radiation of metamaterial surface obtained by photolithography
Authors: Bilinskiy K V , Dorozhkin K V , Moskalenko V D , Kuleshov G E , Badin A V , Trofimov E A , Berdyugin A I
Published: December 2021

In paper results of research of metamaterial surface based on split-ring resonators obtained by photolithography are presented. Numerical simulation of electromagnetic response of the created structure are shown. Experimental researches of the transmission coefficient using quasi-optical methods of continuous and time-domain spectroscopy in the frequency range from 34 to 200 GHz were carried out. Area of broadband screening in the EHF range has been found.
Grouping of particles in a wideband ultrasonic field
Authors: Sukhanov D Y , Rosliakov S N
Published: December 2021

In this paper, we propose to expand the capabilities of wideband levitation and show the possibility of forming a structure of a complex shape based on focusing a wideband field in a given area. Focusing the field of planar radiating arrays makes it possible to form a region of stable levitation in a plane parallel to the arrays. The counter radiation of the two arrays creates a standing wave, at the nodes of which the particles are grouped. The use of a wideband signal makes it possible to create many stable nodes of standing waves in specified areas, and to realize the required shape of the levitating object. Simultaneous monitoring of multiple particles in a wideband ultrasonic field may become a new direction in the development of methods of acoustic trapping and control of particles, as well as technologies of acoustic tweezers.
Wave structure at radar irradiation of homogeneous absorbing media
Authors: Butukhanov V P , Lomukhin Ju L , Atutov E B
Published: December 2021

The work is devoted to the study of the structure of waves excited in bordering media under radar irradiation of both smooth and rough interfaces. It is found that counter propagating waves are excited in bordering absorbing media, which determine backward reflection at the interface. On the other hand, the reflection of the counter propagating wave excites waves with a negative angle of refraction. It was found in this work that when the interface is irradiated with a plane wave during polarization, when the electric field strength vector lies in the plane of incidence, the backward reflection and the refracted wave are increases, and the specular reflection decreases. Electrodynamics models of the back reflection coefficients are developed for both the case of smooth and for the case of uneven interfaces between the media.
Stability of synchronous modes of the system of two connected self-oscillators
Authors: Novikov S S , Kosterova V S
Published: December 2021

In this paper investigate the dynamic instability of a system of two self-oscillators with a strong resonant coupling. The analysis of influence of resonance properties of coupling on stability of synchronous modes was carried out. In the course of the computational experiment, it was possible to observe the different behavior of the system depending on the given initial conditions. The boundaries of destruction of coherent modes are determined.
Flat UWB antenna with optimized ground plate
Authors: Khalil A , Sukhanov D
Published: December 2021

The design of a broadband antenna based on a combination of electric and magnetic emitters is proposed. Antenna size ratios are proposed that provide a wide operating frequency band. The results of numerical modeling of the standing wave ratio and radiation patterns for a particular case with a matching range from 13 GHz to 27 GHz are presented.
Water body measuring pH automated system based on quadcopter
Authors: Lanin E V , Dorozhkin K V , Badin A V , Kuleshov G E , Kazanin V A , Yuzhakov M S
Published: December 2021

The article discusses monitoring water bodies pH level automated system implementation using an unmanned aerial vehicle (UAV). Floating structure prototype for supporting UAV on water surface is described, taking into account creating a rotor thrust theory. Water hydrogen ions monitoring activity concept using a UAV is presented. Testing results water monitoring system in Lake Boyarskoye (Tomsk, Russia) are presented.
The optical and electrical non-invasive methods of measurement for glucose concentration in biological liquids
Authors: Zhexenbayev Y K , Bulembayev T D , Gorst A V , Zavyalova K V , Mironchev A S , Yurchenko E V
Published: December 2021

The article describes the radio-wave and optical methods of determining glucose concentration. The radio-wave method is based on the use of a sensor with a resonant frequency that is displayed when in contact with highly lossy materials and with an extended near-field zone in the resonance area. The optical method is based on studying the influence of glucose concentration (0–20 mmol/l) in bidistilled water on absorption spectra in the range of 190-1000 nm. The article presents the results of the experimental test of the near-field sensor with the pre-produced biological media imitating the human body tissues, and the results of the optical method demonstrate the possibility to measure the concentration with the use of an optical emitter with a wave length of 830 nm.