bluuebunny/crossref_metadata_2025 huggingface dataset:
Steel Lazy Wave Riser Optimization Using Artificial Intelligence Tool
Authors: Lal Mayank , Sebastian Abhilash , Wang Feng , Lu Xiaohua
Published: December 2020

Use of steel lazy wave risers has increased as oil and gas developments are happening in deeper waters or in parts of the world with no pipeline infrastructure. These developments utilize FPSO’s with offloading capabilities necessary for these developments. However, due to more severe motions compared to other floating platforms, traditional catenary form of risers are unsuitable for such developments and this is the reason Steel lazy wave risers (SLWR) are required. SLWRs have shown to have better strength and fatigue performance and lower tensions at the hang-off compared to steel catenary risers. A suitable Lazy-Wave form of the catenary riser is achieved by targeted placement of a custom configured buoyancy section. The strength and fatigue performance of steel lazy wave risers are governed by parameters such as length to start of this buoyancy section, length of the buoyancy section, hang-off angle and the buoyancy factor. Achieving these key performance drivers for a SLWR takes several iterations throughout the design process.

In this paper, genetic algorithm which is an artificial intelligence optimization tool has been used to automate the generation of an optimized configuration of a steel lazy wave riser. This will enable the riser designer to speed up the riser design process to achieve the best location, coverage and size of the buoyancy section. The results that the genetic algorithm routine produces is compared to a parametric study of steel lazy wave risers varying the key performance drivers. The parametric analysis uses a regular wave time domain analysis and captures trends of change in strength and fatigue performance with change in steel lazy wave parameters.
Numerical Analyses of the Effects of Bend Orientation on Sand Erosion in Elbows for Annular Flow
Authors: Kang Rong , Liu Haixiao
Published: December 2020

Sand erosion is a severe problem during the transportation of oil and gas in pipelines. The technology of multiphase transportation is widely applied in production, due to its high efficiency and low cost. Among various multiphase flow patterns, annular flow is a common flow pattern in the transportation process. During the transportation of oil and gas from the hydrocarbon reservoir to the final destination, the flow direction of the mixture in pipelines is mainly changed by the bend orientation. The bend orientation obviously changes the distributions of the liquid film and sand particles in annular flow, and this would further affect the sand erosion in elbows. Computational Fluid Dynamics (CFD) is an efficient tool to investigate the issues of sand erosion in multiphase flow. In the present work, a CFD-based numerical model is adopted to analyze the effects of bend orientation on sand erosion in elbows for annular flow. Volume of Fluid (VOF) method is adopted to simulate the flow field of annular flow, and sand particles in the flow field are tracked by employing Discrete Particle Model (DPM) simultaneously. Then, the particle impingement information is combined with the erosion model to obtain the maximum erosion ratio. The present numerical model is validated by experiments conducted in vertical-horizontal upward elbows. Finally, the effects of various bend orientations on the erosion magnitude are investigated according to the numerical simulations.
Nanofluid MHD combined convection in a porous chamber with various thermal sources
Authors: Sureshkumar S. , Muthukumar S. , Balasundaram K.
Published: December 2020

The impact of various sizes and positions of the heater in a nanofluid-saturated porous lid-driven chamber with a uniform Lorentz force is studied numerically. In this investigation, three different lengths of heater with higher temperature at six different locations along the left sidewall of the cavity are considered. Lower temperature is maintained at the right sidewall. Further, lower and moving upper horizontal walls and the rest of left wall are supposed to be thermally insulated. Based on the finite volume method, the system of nondimensional governing equations is solved by SIMPLE algorithm. The results conclude that the average Nusselt number is reduced with the enhancement of Richardson and Hartmann numbers. When the heater length is reduced from bottom to top, the heat transfer rate is increased for all the considered Richardson, Darcy and Hartmann numbers. In the lower permeability of the porous medium, the effect of solid volume fraction of nanofluid is more vulnerable. In the case of nanofluid, the steady state is reached quickly than the pure fluid.
Soliton solutions of the (3 + 1)-dimensional Yu–Toda–Sassa–Fukuyama equation by the new approach and its numerical solutions
Authors: Bekir Ahmet , Zahran Emad H. M. , Güner Özkan
Published: December 2020

In this paper, we will solve the (3 + 1)-dimensional Yu–Toda–Sassa–Fukuyama equation (YTSFE) which widely investigates the dynamics of solitons and nonlinear wave arising in a fluid dynamics, plasma physics and weakly dispersive media. The Paul-Painlevé approach (PPA) is used for the first time to achieve the soliton solutions of this equation. Furthermore, the numerical solutions of this equation have been proposed by using the variational iteration method (VIM).
Building Resilience After Climate-Related Extreme Events: Lessons Learned from Extreme Precipitation in Schwäbisch Gmünd
Authors: Weißer Britta V. , Jamshed Ali , Birkmann Jörn , McMillan Joanna M.
Published: December 2020

In 2016, heavy precipitation events in Southern Germany demonstrated that pluvial flooding can cause serious damages, not just in large cities but also in small and medium-sized cities. Hazard-oriented disaster management approaches to better address such spatially ubiquitous extreme events are already being developed. However, integrated strategies to reduce risk and to promote climate-resilient development pathways through both private precautionary measures and integrated urban planning are still underdeveloped. Considering the uncertainties associated with heavy precipitation, analyzing and understanding damages, strengthening people’s preparedness and improving preventative measures are central components of resilience building. This paper complements existing empirical studies on households’ preparedness and provides further insight into how resilience to flooding from heavy precipitation in cities can be strengthened. We do this by analyzing the damages caused by one particular heavy precipitation event, the preparedness of people in the affected city and their perceptions of responsibilities for improving precautionary measures. This paper presents the results from a household survey with a total of 1,128 completed questionnaires which was carried out in Schwäbisch Gmünd, Germany. The findings of the household survey illustrate the variety of damages caused by the heavy precipitation event and reveal important differences between households who experienced damages from pluvial flooding and those who did not. Lastly, findings of people’s perception about who is responsible for improved precautions offer interesting insights into tools that might help to enhance resilience building. Finally, the paper formulates recommendations for an improved assessment of resilience-building processes, individual capacities and planning tools to build climate resilience to extreme precipitation events.
Start the Earth System Governance that Integrates “Climate-Altering Technologies”
Authors: PÁSZTOR János
Published: December 2020

Addressing climate emergencies requires a radical social change, and an “earth system” governance approach that combines different factors (including technologies that affect climate). As the Paris Agreement has been reached for four years and came into force for three years, there is a growing recognition that the global average temperature rise cannot be limited to 1.5–2∘C only by emissions reduction or existing carbon removal measures. The reason is that the world has not taken enough actions to deal with the crisis. As reported by IPCC (2018), hundreds of millions of people worldwide are already experiencing the harsh consequences of climate change, from storms to floods, to heatwaves and droughts [IPCC. 2018. “International Panel on Climate Change Special Report on Global Warming of 1.5 Degrees.” https://www.ipcc.ch/sr15 (accessed November 5, 2019)]. According to Spratt and Dunlop (2019), as the climate change intensifies, all sectors of society have realized the need to avoid the risks brought by climate change and to deal with the severe disasters that already exist [Spratt, David, and Ian Dunlop. 2019. “Existential Climate-related Security Risk: A Scenario Approach.” https://docs.wixstatic.com/ugd/148cb0b2c0c79dc4344b279bcf2365336ff23b.pdf (accessed November 5, 2019)]. This raises some profound questions. For instances, should people consider a new responsive measure that is compatible with the natural system which sustains life on the earth, and within the limits of the earth’s tolerance? What forms of decision-making might we need, to help us make the smart collective choices needed for a world where no risk-free options remain? Are familiar governance and decision-making processes still suitable for the goals? Who will make the decisions to promote this transformation? If people really want to change the way they make decisions, they may need to create new forms of governance and decide how this transformation begins and which authority is subject to.
DeepRange
Authors: Mao Wenguang , Sun Wei , Wang Mei , Qiu Lili
Published: December 2020

Acoustic ranging is a technique for estimating the distance between two objects using acoustic signals, which plays a critical role in many applications, such as motion tracking, gesture/activity recognition, and indoor localization. Although many ranging algorithms have been developed, their performance still degrades significantly under strong noise, interference and hardware limitations. To improve the robustness of the ranging system, in this paper we develop a Deep learning based Ranging system, called DeepRange. We first develop an effective mechanism to generate synthetic training data that captures noise, speaker/mic distortion, and interference in the signals and remove the need of collecting a large volume of training data. We then design a deep range neural network (DRNet) to estimate distance. Our design is inspired by signal processing that ultra-long convolution kernel sizes help to combat the noise and interference. We further apply an ensemble method to enhance the performance. Moreover, we analyze and visualize the network neurons and filters, and identify a few important findings that can be useful for improving the design of signal processing algorithms. Finally, we implement and evaluate DeepRangeusing 11 smartphones with different brands and models, 4 environments (i.e., a lab, a conference room, a corridor, and a cubic area), and 10 users. Our results show that DRNet significantly outperforms existing ranging algorithms.
Acoustic Strength-based Motion Tracking
Authors: Ge Linfei , Zhang Qian , Zhang Jin , Huang Qianyi
Published: December 2020

Accurate device motion tracking enables many applications like Virtual Reality (VR) and Augmented Reality (AR). To make these applications available in people's daily life, low-cost acoustic-based motion tracking methods are proposed. However, existing acoustic-based methods are all based on distance estimation. These methods measure the distance between a speaker and a microphone. With a speaker or microphone array, it can get multiple estimated distances and further achieve multidimensional motion tracking. The weakness of distance-based motion tracking methods is that they need large array size to get accurate results. Some systems even require an array larger than 1 m. This weakness limits the adoption of existing solutions in a single device like a smart speaker. To solve this problem, we propose Acoustic Strength-based Angle Tracking (ASAT) System and further implement a motion tracking system based on ASAT. ASAT achieves angle tracking by creating a periodically changing sound field. A device with a microphone will sense the periodically changing sound strength in the sound field. When the device moves, the period of received sound strength will change. Thus we can derive the angle change and achieve angle tracking. The ASAT-based system can obtain the localization accuracy as 5 cm when the distance between the speaker and the microphone is in the range of 3 m.
Teaching RF to Sense without RF Training Measurements
Authors: Cai Hong , Korany Belal , Karanam Chitra R. , Mostofi Yasamin
Published: December 2020

In this paper, we propose a novel, generalizable, and scalable idea that eliminates the need for collecting Radio Frequency (RF) measurements, when training RF sensing systems for human-motion-related activities. Existing learning-based RF sensing systems require collecting massive RF training data, which depends heavily on the particular sensing setup/involved activities. Thus, new data needs to be collected when the setup/activities change, significantly limiting the practical deployment of RF sensing systems. On the other hand, recent years have seen a growing, massive number of online videos involving various human activities/motions. In this paper, we propose to translate such already-available online videos to instant simulated RF data for training any human-motion-based RF sensing system, in any given setup. To validate our proposed framework, we conduct a case study of gym activity classification, where CSI magnitude measurements of three WiFi links are used to classify a person's activity from 10 different physical exercises. We utilize YouTube gym activity videos and translate them to RF by simulating the WiFi signals that would have been measured if the person in the video was performing the activity near the transceivers. We then train a classifier on the simulated data, and extensively test it with real WiFi data of 10 subjects performing the activities in 3 areas. Our system achieves a classification accuracy of 86% on activity periods, each containing an average of 5.1 exercise repetitions, and 81% on individual repetitions of the exercises. This demonstrates that our approach can generate reliable RF training data from already-available videos, and can successfully train an RF sensing system without any real RF measurements. The proposed pipeline can also be used beyond training and for analysis and design of RF sensing systems, without the need for massive RF data collection.
Free Radicals: Making a Case for Battery Modeling
Authors: Howey David A. , Roberts Scott A. , Viswanathan Venkatasubramanian , Mistry Aashutosh , Beuse Martin , Khoo Edwin , DeCaluwe Steven C. , Sulzer Valentin
Published: December 2020

Mathematical modeling to understand battery performance has a history of more than 50 years. The essence of modeling is to make predictions, as is the case across all scientific disciplines; indeed, we can think of models as hypotheses or theories to be tested against experimental data. Models allow us to interpolate between and extrapolate from points in data; without them, a new experiment would need to be run for every use case of a battery.
Towards Quantifying Ion Kinetics at Confined Nanointerfaces Using Electrochemical Fluctuation Methods
Authors: Pendergast Andrew D.
Published: December 2020

2020 Edward G. Weston Summer Research Fellowship – Summary Report
Fluorophosphate Class of Insertion Materials as Efficient Bifunctional Electrocatalysts
Authors: Sharma Lalit
Published: December 2020

2020 F. M. Becket Summer Research Fellowship – Summary Report
A Study on the Mechanism of Impact between Curved Bridge Segments Using Nonsmooth Dynamics
Authors: Li Wenshan , Huang Yong , Xie Guangming
Published: December 2020

It has been observed in many previous earthquakes that impact often occurs between the main girders in curved bridges. An earthquake can result in deck-unseating leading to catastrophic destruction of the structure. In this paper, the nonsmooth multirigid body dynamics method and the set-valued formulation were used to model and analyze the mechanism of impact between the curved bridge segments. The analysis demonstrated that these impacts are the major cause of segment rotation. The main contribution of this paper is to use Newton’s impact law and Coulomb’s friction law to describe the interaction between the curved bridge segments in the form of a set-valued function and to express impacts with friction as a linear complementary problem. For frictionless and frictional contact, the paper considers the single-point and multipoint impacts using the linear complementary formula to detect the unique actual slip-stick conditions of these states. A variety of criteria for distinguishing each case are presented and the results provide the kinetic characteristics of each contact case. The analysis has shown that the impact between the segments of a curved bridge and the tendency of the segments to rotate (and thus detach) are related to the overall geometry, the coefficient of restitution, the coefficient of friction, and the preimpact conditions in the plane of motion. Finally, a theoretical relationship diagram of the impact, rotation slip, and stick condition of the curved bridge segments at the contact point is given. The presented results will be useful for the seismic design of curved bridges.
The Therapeutic Effect of Shugan Xiehuo Formula in the Female Rat Model with Central Precocious Puberty
Authors: Yin Weiping , Li Songmei , Zhang Kun , Xu Yin , Ma Dianfei , Shi Tingting , Xiong Lei , Xia Jie
Published: December 2020

Central precocious puberty (CPP) severely affects children’s physical and mental health and needs to be treated promptly and effectively. This article aimed to research the therapeutic effect of Shugan Xiehuo Formula (SXF) on CPP. A female CPP rat model was established and then treated with leuprolide and different doses of SXF. Sex organ volume and index were measured. Ovaries and uteri were visualized by hematoxylin‐eosin staining. The concentrations of follicle‐stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), and estradiol (E2) in peripheral blood were determined. The expression levels of gonadotropin‐releasing hormone (GnRH), gonadotropin‐releasing hormone receptor (GnRHR), estrogen receptor alpha (ERα), and G protein‐coupled receptor 30 (GPR30) in the hypophysis were investigated by Real‐Time Quantitative Reverse Transcription PCR and western blot. GnRH expression in the hypothalamus and GnRHR expression in the ovary were detected by immunohistochemistry. SXF reduced the volume of the bilateral ovaries, as well as the volumes of the uterus, hypothalamus, and hypophysis in the female CPP rats and diminished the index of the ovary, uterus, hypothalamus, and hypophysis in the female CPP rats (P < 0.05 or P < 0.01). SXF treatment inhibited follicle maturation and uterine wall thickening in the female CPP rats. SXF decreased the concentrations of FSH, LH, PRL, and E2 in the peripheral blood in the female CPP rats (P < 0.01 or P < 0.001). SXF suppressed the expressions of GnRH, GnRHR, ERα, and GPR30 in the hypophysis (P < 0.05), the expression of GnRH in the hypothalamus (P < 0.01), and the expression of GnRHR in the ovaries (P < 0.001) of the female CPP rats. Overall, our study revealed that SXF had therapeutic effects on CPP in female rats. This is worthy of promoting clinically.
Assessing the Clinical Value of Performing CT Scan before Rhinoplasty Surgery
Authors: Jahandideh Hesam , Maleki Delarestaghi Mojtaba , Jan Delaram , Sanaei Ayda
Published: December 2020

Introduction. The endonasal mucosal or anatomic pathologies could lead to poor functional results and dissatisfaction after rhinoplasty. Although computed tomography (CT) scan has become an integral part of the diagnostic paradigm for patients with pathologies of the paranasal sinuses, the use of CT scan for preoperative evaluation of patients seeking rhinoplasty is up for debate. Our aim in this study was to compare the efficacy of CT scan in diagnosing nasal pathologies with other evaluating tools in patients undergoing rhinoplasty. Design. In this randomized controlled trial study, 74 consecutive patients seeking cosmetic rhinoplasty referred to otorhinolaryngology clinic were randomly assigned into three groups based on the perioperative evaluation method: the CT group, the nasal endoscopy group, and the control group (anterior rhinoscopy only). Surgical planning was made according to perioperative findings, and the identified endonasal pathologies were corrected during the surgery. The functional and aesthetic outcomes of the rhinoplasty were assessed by Nasal Obstruction Symptom Evaluation (NOSE), Rhinoplasty Outcome Evaluation (ROE), and the Visual Analogue Scale (VAS) tools before surgery and at 12-month follow-up. Results. All outcome measures improved significantly in either group toward one year after rhinoplasty (all with

p

value <0.05). Subjects in the CT group demonstrated greater improvement in the NOSE, VAS, and ROE compared to other two groups (NOSE:

p

value = 0.17; VAS:

p

value = 0.024; ROE:

p

value = 0.042). Conclusions. According to our study, perioperative CT is associated with greater patients’ satisfaction and quality of life after rhinoplasty compared to either nasal endoscopy or anterior rhinoscopy. A preoperative CT scan may improve the outcomes of rhinoplasty.
Masking Ability of Various Metal Complexing Ligands at 1.0 mM Concentrations on the Potentiometric Determination of Fluoride in Aqueous Samples
Authors: De Silva Sakuni M. , Deraniyagala Samitha , Walpita Janitha K. , Jayaweera Indira , Diyabalanage Saranga , Cooray Asitha T.
Published: December 2020

Fluoride is a common anion present in natural waters. Among many analytical methods used for the quantification of fluoride in natural waters, potentiometric analysis is one of the most widely used methods because of minimum interferences from other ions commonly present in natural waters. The potentiometric analysis requires the use of ionic strength adjusting buffer abbreviated as TISAB to obtain accurate and reproducible data. In most of the reported literature, higher concentrations of strong metal chelating ligands are used as masking agents generally in the concentration range of 1.0 to 0.01 M. In the present study, effectiveness of the masking agents, phosphate, citrate, CDTA ((1,2-cyclohexylenedinitrilo)tetraacetic acid), EDTA (ethylenediaminetetraacetic acid) HE-EDTA ((hydroxyethyl)ethylenediaminetriacetic acid)), triethanolamine, and tartaric acid at 1.0 mM in TISAB solutions was investigated. The experimental data were compared with a commercially available WTW 140100 TISAB solution as the reference buffer. According to the experimental data, the reference buffer always produced the highest fluoride concentrations and the measured fluoride concentrations were in the range of 0.611 to 1.956 mg/L. Out of all the masking agents investigated, only CDTA performed marginally well and approximately a quarter of the samples produced statistically comparable data to the reference buffer. All the other masking agents produced significantly low concentrations compared to the reference buffer. The most probable reasons for the underestimation of fluoride concentrations could be shorter decomplexing time and lower masking agent concentrations.
The Prediction of Metro Shield Construction Cost Based on a Backpropagation Neural Network Improved by Quantum Particle Swarm Optimization
Authors: Liu Lanjun , Liu Denghui , Wu Han , Wang Xinyu
Published: December 2020

The prediction of construction cost of metro shield engineering is of great significance to project management. In this study, we used the rough set theory, a backpropagation (BP) neural network, and quantum particle swarm optimization (QPSO) to establish a prediction model for predicting the metro shield construction costs. The model accounts for the complexity of metro shield construction and the nonlinear relationship between the construction cost factors. First, the factors affecting the construction cost were determined by referring to the Chinese National Standards and analysing the engineering practice of typical metro shield projects. The rough set theory was used to simplify the system of influencing factors to extract the dominant influencing factors and reduce the number of input variables in the BP neural network. Since the BP neural network easily falls into a local minimum and has a slow convergence speed, QPSO was used to optimize the weights and thresholds of the BP neural network. This method combined the strong nonlinear analysis capabilities of the BP and the global search capabilities of the QPSO. Finally, we selected 50 projects in China for a case analysis. The results showed the dominant factors affecting the construction cost of these projects included ten indicators, such as the type of tunnelling machine and the geological characteristics. The determination coefficient, mean absolute percentage error, root mean square error, and mean absolute error, which are frequently used error analysis tools, were used to analyse the calculation errors of different models (the proposed model, a multiple regression method, a traditional BP model, a BP model optimized by the genetic algorithm, and the BP model optimized by the particle swarm optimization). The results showed that the proposed method had the highest prediction accuracy and stability, demonstrating the effectiveness and excellent performance of this proposed method.
Hybrid Blood Purification Therapy Based on Camel Nanoantibody Immunoadsorbent on Patients with Chronic Renal Failure in Nephrology Department
Authors: Ma Tao , Wang Li , Li Xiuyong
Published: December 2020

This paper proposes a study on the effect of hybrid blood purification therapy based on camel nanoantibody immunoadsorbent on chronic renal failure patients in nephrology department. In this paper, the hybrid blood purification therapy based on camel nanoantibody immunoadsorbent was applied to patients with chronic renal failure, and the curative effect of the patients was studied. In order to highlight the effect, a control group was set up for comparison. In this paper, the clearance effect of small molecule toxin, middle molecular toxin, and dialysis adequacy was analyzed. This study found that the average dialysis adequacy of the control group was 1.23% and that of the experimental group was 1.26%. The dialysis adequacy of the experimental group was significantly better than that of the control group. In addition, the clearance effect of small and medium molecular toxins in the experimental group was significantly better than that in the control group. It can be seen that the hybrid blood purification therapy based on camel nanoantibody immunoadsorbent is effective in the treatment of chronic renal failure patients in the department of nephrology. Therefore, it is of great value to apply camel nanoantibody in the clinical treatment of renal failure.
Exosomes Derived from CXCR4-Overexpressing BMSC Promoted Activation of Microvascular Endothelial Cells in Cerebral Ischemia/Reperfusion Injury
Authors: Li Xutong , Zhang Ye , Wang Yong , Zhao Dan , Sun Chengcheng , Zhou Shaoting , Xu Dongsheng , Zhao Jing
Published: December 2020

Background. Ischemic stroke is a severe acute cerebrovascular disease which can be improved with neuroprotective therapies at an early stage. However, due to the lack of effective neuroprotective drugs, most stroke patients have varying degrees of long-term disability. In the present study, we investigated the role of exosomes derived from CXCR4-overexpressing BMSCs in restoring vascular function and neural repair after ischemic cerebral infarction. Methods. BMSCs were transfected with lentivirus encoded by CXCR4 (BMSCCXCR4). Exosomes derived from BMSCCXCR4 (ExoCXCR4) were isolated and characterized by transmission electron microscopy and dynamic light scattering. Western blot and qPCR were used to analyze the expression of CXCR4 in BMSCs and exosomes. The acute middle cerebral artery occlusion (MCAO) model was prepared, ExoCXCR4 were injected into the rats, and behavioral changes were analyzed. The role of ExoCXCR4 in promoting the proliferation and tube formation for angiogenesis and protecting brain endothelial cells was determined in vitro. Results. Compared with the control groups, the ExoCXCR4 group showed a significantly lower mNSS score at 7 d, 14 d, and 21 d after ischemia/reperfusion (

P
<
0.05

). The bEnd.3 cells in the ExoCXCR4 group have stronger proliferation ability than other groups (

P
<
0.05

), while the CXCR4 inhibitor can reduce this effect. Exosomes control (ExoCon) can significantly promote the migration of bEnd.3 cells (

P
<
0.05

), while there was no significant difference between the ExoCXCR4 and ExoCon groups (

P
>
0.05

). ExoCXCR4 can further promote the proliferation and tube formation for the angiogenesis of the endothelium compared with ExoCon group (

P
<
0.05

). In addition, cobalt chloride (COCl2) can increase the expression of β-catenin and Wnt-3, while ExoCon can reduce the expression of these proteins (

P
<
0.05

). ExoCXCR4 can further attenuate the activation of Wnt-3a/β-catenin pathway (

P
<
0.05

). Conclusions. In ischemia/reperfusion injury, ExoCXCR4 promoted the proliferation and tube formation of microvascular endothelial cells and play an antiapoptotic role via the Wnt-3a/β-catenin pathway.
Extended Kalman Filter-Based Approach for Autonomous Synchronization and Ranging in GPS-Denied Environments
Authors: Gu Xiaobo , Tan Weiqiang , Zhang Di , Lu Yudong , Zhan Ruidian
Published: December 2020

Network ranging and clock synchronization based on two-way timing stamps exchange mechanism in complex GPS-denied environments is addressed in this paper. An estimator based on the Extended Kalman filter (EKF) is derived, according to which, the clock skew, clock offset, and ranging information can be jointly estimated. The proposed estimator provides off-line computation by storing the transmitting timing stamps in advance and could be implemented in asymmetrical and asynchronous scenarios. The simulation results show that the proposed estimator achieves a relative good performance than the existed estimators. In addition, a new Bayesian Cramér–Rao Lower Bound (B-CRLB) is derived. Numerous simulation results show that the proposed estimator meets the B-CRLB.
Tracking Objects Based on Multiple Particle Filters for Multipart Combined Moving Directions Information
Authors: Ha Ngo Duong , Shimizu Ikuko , Bao Pham The
Published: December 2020

Object tracking is an important procedure in the computer vision field as it estimates the position, size, and state of an object along the video’s timeline. Although many algorithms were proposed with high accuracy, object tracking in diverse contexts is still a challenging problem. The paper presents some methods to track the movement of two types of objects: arbitrary objects and humans. Both problems estimate the state density function of an object using particle filters. For the videos of a static or relatively static camera, we adjusted the state transition model by integrating the movement direction of the object. Also, we propose that partitioning the object needs tracking. To track the human, we partitioned the human into N parts and, then, tracked each part. During tracking, if a part deviated from the object, it was corrected by centering rotation, and the part was, then, combined with other parts.
Novel Organic Mineral Complex Prevents High-Fat Diet-Induced Changes in the Gut and Liver of Male Sprague-Dawley Rats
Authors: Crawford M. S. , Mohr A. E. , Sweazea K. L.
Published: December 2020

Diet-induced obesity and metabolic syndrome are associated with the onset of gastrointestinal diseases, such as hepatic steatosis and gut inflammation. Prior research shows that a proprietary soil-derived organic mineral complex (OMC) prevents hyperglycemia, endotoxemia, and liver injury in rats fed a high-fat diet (HFD) for 10 weeks. The aim of this study was to further examine the effects of OMC on the liver and gastrointestinal health of these rats. Six-week-old male Sprague-Dawley rats (n = 36) were divided into two dietary groups: Chow or HFD fed for 10 weeks. Animals were further divided (n = 6/group) and administered 0, 0.6, or 3.0 mg/mL OMC in their drinking water. The 10-week HFD resulted in significant liver fat accumulation. Both OMC doses prevented hepatic increases in the glycation end product Nε-(carboxymethyl)lysine (CML) induced by HFD (

p
<
0.05

). Low-dose OMC was associated with higher expression of occludin in the small intestine of rats fed either diet (two-way ANOVA,

p
<
0.042

). Linear discriminant analysis (LDA) effect size (LEfSe) indicated significant differences in fecal microbial composition of untreated HFD-fed rats in comparison to untreated Chow rats at 10 weeks (LDA score > 2.0 : 18). After 10 weeks, untreated HFD-fed rats were also more abundant in bacteria associated with obesity and metabolic disease in comparison to corresponding week 0 samples (LDA score > 2.0 : 31), 10-week untreated Chow (LDA > 2.0 : 18), or 10-week OMC-treated HFD-fed rats (0.6 mg/mL; LDA > 2.0 : 80, 3.0 mg/mL; LDA > 2.0 : 8). Low-dose OMC prevented the HFD-induced increase in the Firmicutes-to-Bacteroidetes (F/B) ratio (

p
<
0.0416

). Study animals treated with OMC exhibited no significant changes in the gut microbiota at week 10, although gut inflammatory biomarkers were not significantly altered by diet or OMC treatment. These results indicate that OMC supplementation ameliorates glycosylation reactions and modifies HFD-induced alterations in the intestinal microbiota.
Mountain Waves Analysis in the Vicinity of the Madrid-Barajas Airport Using the WRF Model
Authors: Díaz-Fernández Javier , Quitián-Hernández Lara , Bolgiani Pedro , Santos-Muñoz Daniel , García Gago Ángel , Fernández-González Sergio , Valero Francisco , Merino Andrés , García‐Ortega Eduardo , Sánchez José Luis , Sastre Mariano , Martín María Luisa
Published: December 2020

Turbulence and aircraft icing associated with mountain waves are weather phenomena potentially affecting aviation safety. In this paper, these weather phenomena are analysed in the vicinity of the Adolfo Suárez Madrid-Barajas Airport (Spain). Mountain waves are formed in this area due to the proximity of the Guadarrama mountain range. Twenty different weather research and forecasting (WRF) model configurations are evaluated in an initial analysis. This shows the incompetence of some experiments to capture the phenomenon. The two experiments showing the best results are used to simulate thirteen episodes with observed mountain waves. Simulated pseudosatellite images are validated using satellite observations, and an analysis is performed through several skill scores applied to brightness temperature. Few differences are found among the different skill scores. Nevertheless, the Thompson microphysics scheme combined with the Yonsei university PBL scheme shows the best results. The simulations produced by this scheme are used to evaluate the characteristic variables of the mountain wave episodes at windward and leeward and over the mountain. The results show that north-northwest wind directions, moderate wind velocities, and neutral or slightly stable conditions are the main features for the episodes evaluated. In addition, a case study is analysed to evidence the WRF ability to properly detect turbulence and icing associated with mountain waves, even when there is no visual evidence available.
Influence of Inlet Angle of Guide Vane on Hydraulic Performance of an Axial Flow Pump Based on CFD
Authors: Xu Lei , Ji Dongtao , Shi Wei , Xu Bo , Lu Weigang , Lu Linguang
Published: December 2020

Axial flow pump has been widely used in hydraulic engineering, agriculture engineering, water supply and sewerage works, and shipbuilding industry. In order to improve the hydraulic performance of pump under off-design working conditions, the influence of the inlet segment axial chord and inlet angle adjustment of the guide vane on the pump segment efficiency and flow filed was simulated by using the renormalization group (RNG)

k
−
ε

turbulent model based on the Reynolds-averaged Navier–Stokes equations. The results indicate that the inlet segment axial chord and inlet angle adjustment of guide vane have a strong influence on the pump segment efficiency. Considering the support function and hydraulic loss of the guide vane, the inlet segment axial chord is set to 0.25 times the axial chord of guide vane. On the basis of the inlet angle of the guide vane under design conditions, when the inlet segment angle is turned counterclockwise, the pump segment efficiency is improved in the lower flow rate region; moreover, the pump segment efficiency is improved in the larger flow rate region when the inlet segment angle is turned clockwise. As the conditions deviate from the design working conditions, the influence of the guide vane inlet angle on the pump segment efficiency increases. If the inlet segment angle is properly adjusted under off-design working conditions, the flow pattern in the guide vane is improved and the hydraulic loss is decreased, because the inlet segment angle matches with the flow direction of impeller outlet; consequently, the pump segment efficiency is increased.
An Authentication Scheme Based on Novel Construction of Hash Chains for Smart Mobile Devices
Authors: Huang Qinglong , Huang Haiping , Wang Wenming , Li Qi , Wu Yuhan
Published: December 2020

With the increasing number of smart mobile devices, applications based on mobile network take an indispensable role in the Internet of Things. Due to the limited computing power and restricted storage capacity of mobile devices, it is very necessary to design a secure and lightweight authentication scheme for mobile devices. As a lightweight cryptographic primitive, the hash chain is widely used in various cryptographic protocols and one-time password systems. However, most of the existing research work focuses on solving its inherent limitations and deficiencies, while ignoring its security issues. We propose a novel construction of hash chain that consists of multiple different hash functions of different output lengths and employ it in a time-based one-time password (TOTP) system for mobile device authentication. The security foundation of our construction is that the order of the hash functions is confidential and the security analysis demonstrates that it is more secure than other constructions. Moreover, we discuss the degeneration of our construction and implement the scheme in a mobile device. The simulation experiments show that the attacker cannot increase the probability of guessing the order by eavesdropping on the invalid passwords.
Uma Experiência Turística no Trem de Passageiros da Estrada de Ferro Vitória a Minas
Authors: Klink Willi Jardim Costa
Published: December 2020

Em razão de consecutivas decisões políticas e ações governamentais em âmbito nacional, a oferta de transporte ferroviário de passageiros no Brasil se concentra, principalmente, no transporte férreo urbano presente em algumas áreas metropolitanas populosas. Há raros exemplos de trens que transportam passageiros de longa distância e alguns poucos trens turísticos que operam trechos curtos e, nem sempre, tem frequência regular. Um dos trechos ferroviários que conta com trem de passageiros, diários e regulares é o da Estrada de Ferro Vitória a Minas, operado pela empresa Vale, que liga as capitais Vitória-ES e Belo Horizonte-MG. Este estudo constitui-se em uma pesquisa exploratóriadescritiva, que empregou a técnica de observação participante, para concretizar o objetivo de registrar as experiências de um passageiro-turista, vividas pelo pesquisador, ao realizar o referido percurso. Como resultado detectou-se que apesar do serviço de passageiros ser oferecido para atender moradores da região e constituir-se em um fator que promove o desenvolvimento regional, ele também apresenta características que podem ser aproveitadas por turistas e por operadoras turísticas.
Cicloturismo no planejamento integrado de cidades e o caso da região metropolitana de Curitiba
Authors: Saldanha Luiz Emerson da Cruz , Freitas Lorena , Balassiano Ronaldo , Fraga Carla
Published: December 2020

O cicloturismo é reconhecido por ser uma atividade que envolve múltiplos segmentos do turismo, assim como conecta ambientes urbanos e rurais. Quando a principal motivação de uma viagem se encontra no percurso entre um destino e outro, permite-se o desenvolvimento em escala local nas regiões abrangidas pela rota de trânsito. Contudo, a implantação de roteiros turísticos para bicicleta requer uma articulação organizacional que envolva diferentes áreas de planejamento e setores da sociedade – principalmente em grandes centros urbanos. Desta forma, o presente artigo apresenta uma contribuição teórico-conceitual sobre o alinhamento do planejamento cicloviário ao turístico, com vistas ao desenvolvimento do cicloturismo. Por meio de uma revisão bibliográfica que contemplou artigos científicos e documentos estratégicos nacionais e internacionais, foram levantados conceitos orientadores de gestão e avaliadores de infraestrutura – como os polos de ciclismo e os critérios de qualidade, respectivamente. O estudo de caso sobre a Região Metropolitana de Curitiba foi realizado para melhor compreender a aplicabilidade destas ferramentas para o contexto brasileiro. Os resultados destacam uma perspectiva interdisciplinar para o planejamento da rede viária em relação à atratividade do destino e suas respectivas condições ambientais e demográficas.
Pensar, gostar e considerar importante a prática de atividade física aumentam as chances de ser ativo no lazer?
Authors: Oliveira Elaynne Silva de , Costa Claudia Vanisse de Brito , Souza Sergio Augusto Rosa de , Carvalho Wellington Roberto Gomes de , Salvador Emanuel Péricles
Published: December 2020

Embora reconhecida como comportamento de extrema importância na saúde da população, a prática de atividade física regular ainda é um grande desafio. Objetivo: verificar o nível de atividade física no lazer e possíveis fatores correlatados em uma comunidade acadêmica do nordeste brasileiro. Metodologia: trata-se de um estudo transversal, constituído por discentes, docentes e técnicos administrativos, utilizou-se como instrumento “Mapa de Atividade Física e Saúde-MAFIS”, realizou-se estatística descritiva, teste de Qui quadrado, com posterior montagem do modelo de regressão logística. Resultados: 52,1% atingiram as recomendações de atividade física (AF), os homens apresentam 65,3% (OR: 1,65; IC95%: 1,29-2,11) mais chance de serem ativos, quem gosta de AF tem duas (OR: 2,02; IC95%: 0,82-4,96) a 4,8 (OR: 4,84; IC95%: 1,99-11,8) vezes mais chance de praticar AF, achar importante fazer AF (OR: 2,23; IC95%: 0,48-10,4) e menos dias sentado aumenta de 48,3% (OR: 1,48; IC95%: 1,032- 2,130) a 53,3% (OR: 1,53; IC95%: 1,09-2,13) a chance de fazer AF e quem pensa em fazer AF (OR: 0,362; IC: 0,203-0,645) tem menos chance de ser ativo. Conclusão: Gostar, considerar importante e menos dias sentados aumentam as chances de fazer atividade física, já pensar sempre em fazer, diminui a chance de ser ativo no lazer.
uso da tecnologia no ensino da anatomia humana: revisão sistemática da literatura de 2017 a 2020
Authors: Boff Tália Cássia , Scaramussa Alexandre Bachietti , Christianetti Manuela , Rossi Renata Calciolari , Silva Débora Tavares de Resende e
Published: December 2020

A tecnologia destaca-se como agente de avanço, principalmente na área da saúde. O estudo da anatomia humana nos cursos de medicina permanece tradicionalista com palestras teóricas e dissecção de cadáveres, por isso, metodologias tecnológicas parecem auxiliar o ensino, tornando-o interativo. Assim, o objetivo do estudo é analisar as perspectivas do uso de tecnologias no ensino da anatomia humana para inseri-las na graduação em medicina. Realizou-se uma revisão sistemática da literatura abrangendo artigos publicados entre janeiro de 2017 a março de 2020 nas bases de dados eletrônicas PubMed e Science Direct. Elencaram-se três critérios de inclusão: estudos com estudantes de medicina ou direcionado aos estudantes de medicina, estudos com residentes de medicina e estudos que avaliam o uso do desenvolvimento tecnológico no ensino da anatomia humana; e três de exclusão: estudos com animais, estudos com estudantes de outros cursos da área da saúde e estudos envolvendo área ou técnica cirúrgica específica. Onze artigos foram lidos na íntegra. Como resultado smartphones, código de resposta rápida (QR), realidade virtual (VR), modalidades impressas tridimensionais (3DP), próteses em 3D e outras tecnologias beneficiaram os alunos no aprendizado anatômico, os quais relataram instrumento atraente, de fácil manejo e acessível mesmo distante do laboratório. Além disso, demonstrou-se maior interesse dos acadêmicos em associar métodos tradicionais com as novas tecnologias. As tecnologias se mostraram eficazes no ensino da anatomia humana, visto que a maior parte dos estudos comprovou seu potencial enriquecedor nas avaliações que atingiram resultados iguais e melhores do que o ensino com as práticas tradicionais.
Geotermobarometria de safirina e granada granulito do afloramento da Praia da Paciência, Salvador, Bahia – Cinturão Salvador-Esplanada-Boquim
Authors: Rodrigues Daniela Leal , Oliveira Jailma Santos de Souza de , Moraes Renato de
Published: December 2020

O afloramento da Praia da Paciência, Salvador, Bahia, está inserido no contexto geotectônico do Cráton do São Francisco, no extremo sul do Cinturão Salvador-Esplanada-Boquim. Neste trabalho foi realizado estudo sobre granada granulito coexistindo com safirina granulito, presentes no afloramento. O primeiro apresenta porfiroblastos de granada e ortopiroxênio envolvidos por matriz de plagioclásio ± feldspato potássico ± quartzo, e biotita retrometamórfica. Safirina granulito apresenta constituição bastante residual, formada principalmente por simplectitos entre safirina + ortopiroxênio ± espinélio ± cordierita, e na matriz há menores quantidades de plagioclásio, quartzo, feldspato potássico, com biotita retrometamórfica em profusão envolvendo as demais fases. No granada granulito, a granada é uma solução sólida dominada pelo par almandina-piropo, com composição entre alm55prp43, nos núcleos, e alm60prp39, nas bordas, bem como conteúdo de Al em ortopiroxênio entre 0,30–0,43 apfu nos porfiroblastos. No safirina granulito, Al em ortopiroxênio varia entre 0,27–0,40 apfu. Condições P-T de pico metamórfico de ~1,04 GPa e ~1.015°C foram obtidas para o granada granulito, e XMg em ortopiroxênio no safirina granulito indicou, na pseudosseção, estabilidade até T próximas a 1.030°C. Essas condições são compatíveis com metamorfismo de temperatura ultra-alta e este é o primeiro relato desse tipo de metamorfismo no Cinturão Salvador-Esplanada-Boquim. O metamorfismo imediatamente pós-pico teria decorrido em trajetória de descompressão quase isotérmica, consistente com microestruturas de reações identificadas, até o limite próximo a 0,75 GPa e 930°C, via pseudosseção, ainda em alta temperatura. A difusão entre Fe-Mg e back-reactions atuaria intensamente durante os estágios seguintes de resfriamento no safirina granulito, resultando em temperaturas calculadas via termômetro Opx-Spr inferiores às de fácies granulito, entre X e Y°C.
Turguêniev
Authors: Junqueira Samuel , Bianchi Fátima
Published: December 2020

A criação de tipos literários é um dos pontos altos da obra de Turguêniev. O homem supérfluo e o jovem radical são os exemplos mais lembrados. E tão impressionante quanto estes é o retrato que o escritor faz do camponês russo em Memórias de um caçador. Praticamente todos os grandes literatos russos do século XIX abordaram essa temática, mas Turguêniev foi muito além. Neste artigo, pretendemos demonstrar, por meio de uma análise do conto “Uma relíquia viva”, as inovações realizadas pelo escritor na caracterização dessa figura. Subordinando a estrutura narrativa à voz de uma camponesa e conferindo-lhe uma feição cristã até então inédita, Turguêniev dá vida a uma figura extremamente marcante e comovente.