bluuebunny/crossref_metadata_2025 huggingface dataset:
Fuzzy Logic Controller for Force Feedback Control of Quadcopter via Tether
Authors: Breese Bennett , Scott Drew , Barawkar Shraddha , Kumar Manish
Published: January 2021

Tethered drone systems can be used to perform long-endurance tasks such as area surveillance and relay stations for wireless communication. However, all the existing systems use tethers only for data and power transmission from a stationary point on the ground. This work presents a control strategy that enables a quadcopter to follow a moving tether anchor. A force feedback controller is implemented using Fuzzy Logic. Using force-based strategy provides effective compliance between the tether’s anchor and the drone. The drone can thus be controlled by mere physical movement/manipulation of tether. This enhances the safety of current tethered drone systems and simplifies the flying of drones. Fuzzy Logic provides an intuitive edge to the control of such systems and allows handling noise in force sensors. Extensive simulation results are presented in this paper showing the effectiveness of the proposed control scheme.
Design of a Parallel Elastic Hopper With a Wrapping Cam Mechanism and Template Based Virtually Tunable Damping Control
Authors: Candan Sinan Şahin , Karagöz Osman Kaan , Yazıcıoğlu Yiğit , Saranlı Uluç
Published: January 2021

In this study, mechanical design and control of a novel parallel elastically actuated (PEA) legged robot are presented. Motion under analysis is limited to vertical apex to apex hopping. Robot is composed of a symmetric four link mechanism as the leg, a brushless direct-drive DC motor and a wrapping cam with extension spring. Controller is based on templates (the simplest model) and anchors (more realistic model) scheme, where the template is the Spring Loaded Inverted Pendulum (SLIP) including a viscous damper which is virtually tunable. For a desired apex, required damping constant is calculated to provide necessary energy to SLIP from an approximate analytical map. Template motion is realized in the anchor model by equating its dynamics to the template dynamics through torque control to equate energy inputs and a wrapping cam to equate potential energies. During the motion, a string is wrapped around a cam by relative motion between two links of the four link mechanism. The string pulls the spring and creates a nonlinear elongation function. Desired elongation is obtained from the required template potential energy and the necessary cam profile is calculated analytically. Thus, a linear compression spring is realized with a tension spring with cam. Static force experiments are performed to show that cam works as desired. Overall simulations and details of mechanical design are presented. This novel PEA robot architecture provides an accurate and energy efficient solution with a simple mechanical design.
Including Image-Based Perception in Disturbance Observer for Warehouse Drones
Authors: Chen Zhu , Liang Xiao , Zheng Minghui
Published: January 2021

Grasping and releasing objects would cause oscillations to delivery drones in the warehouse. To reduce such undesired oscillations, this paper treats the to-be-delivered object as an unknown external disturbance and presents an image-based disturbance observer (DOB) to estimate and reject such disturbance. Different from the existing DOB technique that can only compensate for the disturbance after the oscillations happen, the proposed image-based one incorporates image-based disturbance prediction into the control loop to further improve the performance of the DOB. The proposed image-based DOB consists of two parts. The first one is deep-learning-based disturbance prediction. By taking an image of the to-be-delivered object, a sequential disturbance signal is predicted in advance using a connected pre-trained convolutional neural network (CNN) and a long short-term memory (LSTM) network. The second part is a conventional DOB in the feedback loop with a feedforward correction, which utilizes the deep learning prediction to generate a learning signal. Numerical studies are performed to validate the proposed image-based DOB regarding oscillation reduction for delivery drones during the grasping and releasing periods of the objects.
Design Analysis of a Distributed Actuation-Sensing System Using Direct Field-Feedback for Eddy-Current Pattern Control
Authors: Li Min , Lee Kok-Meng
Published: January 2021

This paper presents a direct field-feedback method with an observer for precise control of an eddy-current density (ECD) field induced in an electrically conductive-plate by a set of individually manipulatable currents. The magnetic flux density (MFD) generated by the ECD is measured by an array of MFD sensors, and fed back for compensating external disturbances and time-varying effects of the system parameters and ECD model inaccuracy. For feedback control of the multiple-input and multiple-output (MIMO) distributed-parameter system, a distributed current source (DCS) method is used to formulate the ECD system in state space, where the conductor is discretized into elemental ECD sources as system state variables providing a basis to design the state controller and observer. Based on the observability of the MFD sensing system and the controllability of the EM actuation system, the controller and observer were designed using a pole-placement method. Results illustrating the design concept are presented, demonstrating the feasibility and efficiency of the proposed method; both well-defined and arbitrary EC contours are considered. While illustrated in the context of controlling an EC pattern, the methods presented here provide the essential basis for designing and controlling a distributed-parameter system utilizing the physical fields of the system for state feedback and error compensation with a distributed set of actuators and sensors.
Uncertainty and Disturbance Estimator-Based Robust Region Tracking Control for Multiple Quadrotors
Authors: Lu Qi , Ren Beibei , Ji Yuan-dong
Published: January 2021

In this paper, the decentralized uncertainty and disturbance estimator (UDE)-based robust region reaching controller is developed to drive a swarm of quadrotors with the full degrees-of-freedom, nonlinear, coupled and underactuated dynamics to track the trajectory of a moving target region while avoiding collisions among themselves. The backstepping technique is utilized to seamlessly fuse the UDE into the region reaching control framework with the function of estimating and compensating the model uncertainties and external disturbances. Simulation studies are carried out to demonstrate the effectiveness of the proposed method for achieving the moving target trajectory tracking even in the presence of external disturbances.
Parameter Sensitivity Analysis of Piezoelectrically-Actuated Flexural/Torsional Vibrating Beams
Authors: Salehzadeh Roya , Candelino Nicholas , Khodaei Mohammad Javad , Mehrvarz Amin , Jalili Nader
Published: January 2021

A numerical parameter sensitivity analysis is performed on the bending and torsional vibrations of a flexural-torsional vibrating beam gyroscope model. The gyroscope analyzed in this work is comprised of a rotating cantilever beam with a point-mass attached to its free end and a piezoelectric actuator fixed to a portion of its length. The governing equations of motion are derived using extended Hamilton’s principle and the steady-state magnitude response of the system is obtained through frequency domain methods. A sensitivity analysis is then carried out for the parameters including rotational speed of the base, the length of the beam, the location of the piezoelectric patch, and the location of the added point mass along the beam’s length. It is observed that, in the region surrounding specific configurations, small variations in the rotation rate, beam length and the location of the piezoelectric patch will result in significant changes to the amplitudes of the coupled vibrations and produce peaks in the sensitivity curves. Further, the amplitude of vibration tends to increase as the location of the added point-mass is moved closer to the free end. Generally, the bending modes are more sensitive to all of these parameter variations than are the torsional modes.
Control-Oriented Model Development and Experimental Validation for a Modern Diesel Engine
Authors: Yang Kuo , Chen Pingen
Published: January 2021

Modern Diesel engines have become highly complex multi-input multi-output systems. Controls of modern Diesel engines to meet various requirements such as high fuel efficiency and low NOx and particulate matter (PM) emissions, remain a great challenge for automotive control community. While model-based controls have demonstrated significant potentials in achieving high Diesel engine performance. Complete and high-fidelity control-oriented Diesel engine models are much needed as the foundations of model-based control system development. In this study, a semi-physical, mean-value control-oriented model of a turbocharged Diesel engine equipped with high-pressure exhaust gas recirculation (EGR) and variable geometry turbocharger (VGT) is developed and experimentally validated. The static calibration of Diesel engine model is achieved with the least-square optimization methodology using the experimental test data from a physical Diesel engine platform. The normalized root mean square errors (NRMSEs) of the calibration results are in the range of 0.1095 to 0.2582. The cross-validation results demonstrated that the model was capable of accurately capturing the engine torque output and NOx emissions with the control inputs of EGR, VGT and Start of Injection timing (SOI) in wide-range operating conditions.
For Sport Journalists to Count and Report Major Championships in Golf: Per Coherent Definition and Conventional Classification, Nicklaus Has 20 Majors
Authors: Gaski John F.
Published: January 2021

Over the past 3 decades or so, some variation and revision have been introduced into the recording, reporting, and interpretation of the prime historical benchmark of individual golf achievement: number of established major tournaments won. In the interest of accuracy, consistency, and even equity, some analytic record-keeping suggestions are proffered here, based on coherence and logic, toward presenting the history of golf’s major championships in the fairest possible way. Idiosyncrasies of that historical sequence mean that the resolution is not obvious and more taxonomic work remains to be done. However, acceptance of the principles and conventions proposed herein may move the golf history culture and even basic golf chronicling closer to advantageous closure. One competitive implication of this reanalysis applies, significantly, to the total of “majors” won by historical greats Jack Nicklaus, Bobby Jones, and Tiger Woods.
Associations Between Major Life Changes and Pedometer-Determined Physical Activity Over 4 Years in Middle-Aged Adults in the Cardiovascular Risk in Young Finns Study
Authors: Salin Kasper , Kankaanpää Anna , Yang Xiaolin , Tammelin Tuija H. , Magnussen Costan G. , Telama Risto , Hutri-Kähönen Nina , Viikari Jorma S.A. , Raitakari Olli T. , Hirvensalo Mirja
Published: January 2021

Background: To examine if major life changes over a 4-year period among 34- to 49-year-old adults (mean = 41.8, SD = 5.0) were associated with a change in physical activity in men (37.7%) and women (62.3%). Methods: Daily steps and aerobic steps (steps that lasted for at least 10 min without interruption at a pace of >60 steps/min) were collected from 1051 participants in 2007 and 2011. Changes in marital status, work status, and residence and the birth of a child were determined from both time points. A latent change score model was used to examine mean changes in daily total steps, aerobic steps, and nonaerobic steps (total steps minus aerobic steps). Results: Women who had a first child in the 4-year period had a decrease in their nonaerobic steps (P = .001). Men who divorced in the 4-year period had a decrease in their nonaerobic steps (P = .020), whereas women who recoupled decreased their total steps (P = .030). Conclusions: Counseling for parents having a first child on how to increase physical activity in their everyday life could potentially have an influence on an individual’s physical activity.
Obstructive uropathy from a giant urinary bladder stone: a rare urological emergency
Authors: Mukherjee Subhabrata , Sinha Rajan Kumar , Hamdoon Mussab , Abbaraju Jai
Published: January 2021

A 53-year-old man presented with lower urinary tract symptoms and recurrent urinary tract infections since last 3 years without being investigated or treated properly. Examination revealed a hard mobile lump in the pelvis, and blood investigations showed raised serum creatinine of 2.9 mg/dL. Subsequent urgent ultrasound scan showed a large urinary bladder stone with bilateral hydroureteronephrosis, and X-ray kidney, ureter and bladder demonstrated a 9 cm×6 cm elliptical radio-opaque shadow in the pelvis. He underwent emergency admission followed by open cystolithotomy on the next day. He was discharged after 48 hours with a urethral catheter. After 2 weeks, his renal function recovered completely; repeat ultrasound scan revealed complete resolution of hydronephrosis. Urethral catheter was removed following a normal cystogram. Uroflowmetry after 6 weeks revealed underlying bladder outlet obstruction, and he was started on alpha blocker which improved his urinary flow.
Stretch too far: rectus sheath haematoma secondary to repetitive trauma and increased intra-abdominal pressure
Authors: Reider Joshua , Radtke Logan , Heiberger Caleb Joseph , Yim Douglas
Published: January 2021

A 26-year-old man presented with a 4-week history of right lower quadrant abdominal pain which was managed conservatively at home with ibuprofen. Three days later, he presented to the emergency department with worsening pain and swelling following an episode of coughing and slipping in the bathroom. Following his admission, CT angiography showed an active bleed into a 4.6×6.7×11 cm right rectus sheath haematoma, just inferior to the umbilicus. The patient was then referred to interventional radiology for an angiogram and coil embolisation. A superselective branch angiogram showed contrast extravasation from a medial branch of the right inferior epigastric artery, successfully embolised without incident.
Monitoring of mitochondrial oxygenation during perioperative blood loss
Authors: Harms Floor A , Brandt-Kerkhof Alexandra R M , Mik Egbert G
Published: January 2021

One of the challenges in the management of acute blood loss is to differentiate whether blood transfusion is required or not. The sole use of haemoglobin values might lead to unnecessary transfusion in individual cases. The suggestion is that mitochondrial oxygen tension can be used as an additional monitoring technique to determine when blood transfusion is required. In this case report, we report mitochondrial oxygen measurements in a patient with perioperative blood loss requiring blood transfusion.
Protecting the world’s finest athletes: periodic health evaluation practices of the top performing National Olympic Committees from the 2016 Rio or 2018 PyeongChang Olympic Games
Authors: Nabhan Dustin , Taylor David , Lewis Melie , Bahr Roald
Published: January 2021

Aim

To describe the periodic health evaluation (PHE) practices of the top performing National Olympic Committees (NOCs).

Methods

We sent a survey to NOCs finishing in the top 8 for medal count at the 2016 Rio Olympic Games or 2018 PyeongChang Olympic Games. The survey included four sections: (1) PHE staff composition and roles, (2) beliefs regarding the PHE, (3) a ranking of risk factors for future injury and (4) details on the elements of the PHE.

Results

All 14 NOCs with top 8 finishes at the 2016 Rio Olympic Games or 2018 PyeongChang Olympic Games completed the survey. NOCs included a median of seven staff specialties in the PHE, with physicians and physiotherapists having the highest level of involvement. There was agreement that PHEs are effective in identifying current health conditions (13/14) and that athletes should receive individualised action plans after their PHE (14/14), but less agreement (6/14) that PHEs can predict future injury. The practices of NOCs were diverse and often specific to the athlete population being tested, but always included the patient’s health history, laboratory studies, cardiovascular screening and assessments of movement capacity. The top three risk factors for future injury were thought to be previous injury, age and training experience.

Conclusions

Among the top performing NOCs, the PHE is a comprehensive, multidisciplinary process aimed to identify existing conditions and provide baseline health and performance profiles in the event of future injury. Research linking PHEs to injury prevention is needed.
Persistent opioid use and opioid-related harm after hospital admissions for surgery and trauma in New Zealand: a population-based cohort study
Authors: Gong Jiayi , Merry Alan Forbes , Beyene Kebede A , Campbell Doug , Frampton Chris , Jones Peter , McCall John , Moore Matthew , Chan Amy Hai Yan
Published: January 2021

Introduction

Opioid use has increased globally for the management of chronic non-cancer-related pain. There are concerns regarding the misuse of opioids leading to persistent opioid use and subsequent hospitalisation and deaths in developed countries. Hospital admissions related to surgery or trauma have been identified as contributing to the increasing opioid use internationally. There are minimal data on persistent opioid use and opioid-related harm in New Zealand (NZ), and how hospital admission for surgery or trauma contributes to this. We aim to describe rates and identify predictors of persistent opioid use among opioid-naïve individuals following hospital discharge for surgery or trauma.

Methods and analysis

This is a population-based, retrospective cohort study using linked data from national health administrative databases for opioid-naïve patients who have had surgery or trauma in NZ between January 2006 and December 2019. Linked data will be used to identify variables of interest including all types of hospital surgeries in NZ, all trauma hospital admissions, opioid dispensing, comorbidities and sociodemographic variables. The primary outcome of this study will be the prevalence of persistent opioid use. Secondary outcomes will include mortality, opioid-related harms and hospitalisation. We will compare the secondary outcomes between persistent and non-persistent opioid user groups. To compute rates, we will divide the total number of outcome events by total follow-up time. Multivariable logistic regression will be used to identify predictors of persistent opioid use. Multivariable Cox regression models will be used to estimate the risk of opioid-related harms and hospitalisation as well as all-cause mortality among the study cohort in a year following hospital discharge for surgery or trauma.

Ethics and dissemination

This study has been approved by the Auckland Health Research Ethics Committee (AHREC- AH1159). Results will be reported in accordance with the Reporting of studies Conducted using Observational Routinely collected health data statement (RECORD).
Protocol for the development of the Wales Multimorbidity e-Cohort (WMC): data sources and methods to construct a population-based research platform to investigate multimorbidity
Authors: Lyons Jane , Akbari Ashley , Agrawal Utkarsh , Harper Gill , Azcoaga-Lorenzo Amaya , Bailey Rowena , Rafferty James , Watkins Alan , Fry Richard , McCowan Colin , Dezateux Carol , Robson John P , Peek Niels , Holmes Chris , Denaxas Spiros , Owen Rhiannon , Abrams Keith R , John Ann , O"Reilly Dermot , Richardson Sylvia , Hall Marlous , Gale Chris P , Davies Jan , Davies Chris , Cross Lynsey , Gallacher John , Chess James , Brookes Anthony J , Lyons Ronan A
Published: January 2021

Introduction

Multimorbidity is widely recognised as the presence of two or more concurrent long-term conditions, yet remains a poorly understood global issue despite increasing in prevalence.

We have created the Wales Multimorbidity e-Cohort (WMC) to provide an accessible research ready data asset to further the understanding of multimorbidity. Our objectives are to create a platform to support research which would help to understand prevalence, trajectories and determinants in multimorbidity, characterise clusters that lead to highest burden on individuals and healthcare services, and evaluate and provide new multimorbidity phenotypes and algorithms to the National Health Service and research communities to support prevention, healthcare planning and the management of individuals with multimorbidity.

Methods and analysis

The WMC has been created and derived from multisourced demographic, administrative and electronic health record data relating to the Welsh population in the Secure Anonymised Information Linkage (SAIL) Databank. The WMC consists of 2.9 million people alive and living in Wales on the 1 January 2000 with follow-up until 31 December 2019, Welsh residency break or death. Published comorbidity indices and phenotype code lists will be used to measure and conceptualise multimorbidity.

Study outcomes will include: (1) a description of multimorbidity using published data phenotype algorithms/ontologies, (2) investigation of the associations between baseline demographic factors and multimorbidity, (3) identification of temporal trajectories of clusters of conditions and multimorbidity and (4) investigation of multimorbidity clusters with poor outcomes such as mortality and high healthcare service utilisation.

Ethics and dissemination

The SAIL Databank independent Information Governance Review Panel has approved this study (SAIL Project: 0911). Study findings will be presented to policy groups, public meetings, national and international conferences, and published in peer-reviewed journals.
Pregnancy outcome in thoracic aortic disease data from the Registry Of Pregnancy And Cardiac disease
Authors: Campens Laurence , Baris Lucia , Scott Nandita S. , Broberg Craig S , Bondue Antione , Jondeau Guillaume , Grewal Jasmine , Johnson Mark R , Hall Roger , De Backer Julie , Roos-Hesselink Jolien W
Published: January 2021

Background

Cardiovascular disease is the leading cause of death during pregnancy with thoracic aortic dissection being one of the main causes. Thoracic aortic disease is commonly related to hereditary disorders and congenital heart malformations such as bicuspid aortic valve (BAV). Pregnancy is considered a high risk period in women with underlying aortopathy.

Methods

The ESC EORP Registry Of Pregnancy And Cardiac disease (ROPAC) is a prospective global registry that enrolled 5739 women with pre-existing cardiac disease. With this analysis, we aim to study the maternal and fetal outcome of pregnancy in women with thoracic aortic disease.

Results

Thoracic aortic disease was reported in 189 women (3.3%). Half of them were patients with Marfan syndrome (MFS), 26% had a BAV, 8% Turner syndrome, 2% vascular Ehlers-Danlos syndrome and 11% had no underlying genetic defect or associated congenital heart defect. Aortic dilatation was reported in 58% of patients and 6% had a history of aortic dissection. Four patients, of whom three were patients with MFS, had an acute aortic dissection (three type A and one type B aortic dissection) without maternal or fetal mortality. No complications occurred in women with a history of aortic dissection. There was no significant difference in median fetal birth weight if treated with a beta-blocker or not (2960 g (2358–3390 g) vs 3270 g (2750–3570 g), p value 0.25).

Conclusion

This ancillary analysis provides the largest prospective data review on pregnancy risk for patients with thoracic aortic disease. Overall pregnancy outcomes in women with thoracic aortic disease followed according to current guidelines are good.
Estimating the burden of the COVID-19 pandemic on mortality, life expectancy and lifespan inequality in England and Wales: a population-level analysis
Authors: Aburto Jose Manuel , Kashyap Ridhi , Schöley Jonas , Angus Colin , Ermisch John , Mills Melinda C , Dowd Jennifer Beam
Published: January 2021

Background

Deaths directly linked to COVID-19 infection may be misclassified, and the pandemic may have indirectly affected other causes of death. To overcome these measurement challenges, we estimate the impact of the COVID-19 pandemic on mortality, life expectancy and lifespan inequality from week 10 of 2020, when the first COVID-19 death was registered, to week 47 ending 20 November 2020 in England and Wales through an analysis of excess mortality.

Methods

We estimated age and sex-specific excess mortality risk and deaths above a baseline adjusted for seasonality with a systematic comparison of four different models using data from the Office for National Statistics. We additionally provide estimates of life expectancy at birth and lifespan inequality defined as the SD in age at death.

Results

There have been 57 419 (95% prediction interval: 54 197, 60 752) excess deaths in the first 47 weeks of 2020, 55% of which occurred in men. Excess deaths increased sharply with age and men experienced elevated risks of death in all age groups. Life expectancy at birth dropped 0.9 and 1.2 years for women and men relative to the 2019 levels, respectively. Lifespan inequality also fell over the same period by 5 months for both sexes.

Conclusion

Quantifying excess deaths and their impact on life expectancy at birth provide a more comprehensive picture of the burden of COVID-19 on mortality. Whether mortality will return to—or even fall below—the baseline level remains to be seen as the pandemic continues to unfold and diverse interventions are put in place.
Impact of correlations between $$a_{\mu }$$ and $$\alpha _\text {QED}$$ on the EW fit
Authors: Malaescu Bogdan , Schott Matthias
Published: January 2021

We study the potential impact on the electroweak (EW) fits due to the tensions between the current determinations of the hadronic vacuum polarisation (HVP) contributions to the anomalous magnetic moment of the muon ($$a_{\mu }$$

a
μ

), based on either phenomenological dispersion integrals using measured hadronic spectra or on Lattice QCD calculations. The impact of the current tension between the experimental measurement of $$a_{\mu }$$

a
μ

and the total theoretical prediction based on the phenomenological calculations of the HVP is also studied. The correlations between the uncertainties of the theoretical predictions of $$a_{\mu }$$

a
μ

and of the running of $$\alpha _\mathrm{QED}$$

α
QED

are taken into account in the studies. We conclude that the impact on the EW fit can be large in improbable scenarios involving global shifts of the full HVP contribution, while it is much smaller if the shift is restricted to a lower mass range and/or if the shift in $$\alpha _\text {QED}$$

α
QED

is obtained from that in $$a_{\mu }$$

a
μ

through appropriate use of the correlations. Indeed, the latter scenarios only imply at most a 2.6/16 increase in the $$\chi ^2/\text {n.d.f.} $$

χ
2

/
n.d.f.

of the EW fits and relatively small changes for the resulting fit parameter values.
Generalized word shift graphs: a method for visualizing and explaining pairwise comparisons between texts
Authors: Gallagher Ryan J. , Frank Morgan R. , Mitchell Lewis , Schwartz Aaron J. , Reagan Andrew J. , Danforth Christopher M. , Dodds Peter Sheridan
Published: January 2021

A common task in computational text analyses is to quantify how two corpora differ according to a measurement like word frequency, sentiment, or information content. However, collapsing the texts’ rich stories into a single number is often conceptually perilous, and it is difficult to confidently interpret interesting or unexpected textual patterns without looming concerns about data artifacts or measurement validity. To better capture fine-grained differences between texts, we introduce generalized word shift graphs, visualizations which yield a meaningful and interpretable summary of how individual words contribute to the variation between two texts for any measure that can be formulated as a weighted average. We show that this framework naturally encompasses many of the most commonly used approaches for comparing texts, including relative frequencies, dictionary scores, and entropy-based measures like the Kullback–Leibler and Jensen–Shannon divergences. Through a diverse set of case studies ranging from presidential speeches to tweets posted in urban green spaces, we demonstrate how generalized word shift graphs can be flexibly applied across domains for diagnostic investigation, hypothesis generation, and substantive interpretation. By providing a detailed lens into textual shifts between corpora, generalized word shift graphs help computational social scientists, digital humanists, and other text analysis practitioners fashion more robust scientific narratives.
The EPR paradox and the uncertainty principle
Authors: McCulloch Michael E. , Giné Jaume
Published: January 2021

The EPR paradox appears when measurement results of some properties of two distantly entangled particles are correlated in a way that cannot be explained classically, and apparently violate locality. The resolution of the paradox depends on one’s interpretation of quantum mechanics. Explanations from quantum mechanics remain commonplace today, but they fail to explain the EPR (Einstein, Podolsky and Rosen) paradox totally in a way than can be accepted by the whole community. Here, we present a simple resolution to this paradox in which the uncertainty in the energy of the two-particle system is reduced by its lack of interaction during the journey so that the uncertainty in time becomes greater than the time they have been separating. Consequently, the present and past become indistinguishable because when we measure an observable in the system its value is the same as if the two particle were still together or very close. It is also argued that the destruction of information as the present and past become identical should release heat by Landauer’s principle, and this might make this proposal testable.
Numerical treatment of melting heat transfer and entropy generation in stagnation point flow of hybrid nanomaterials (SWCNT-MWCNT/engine oil)
Authors: Ullah Ikram , Hayat Tasawar , Alsaedi Ahmed , Fardoun Habib M.
Published: January 2021

Present attempt inspects the entropy analysis and melting effect in flow of hybrid nanomaterials consisting of CNTs nanoparticles and engine oil Flow is by a stretching cylinder. Formulation is accountable to the viscous dissipation, velocity slip and thermal radiation impacts. In order to estimate the disorder within the thermo-physical frame, second-order analysis has been used. The governing system with the imposed boundary condition is dimensionless via proper variables. Numerical outcomes are expressed graphically and analyzed. Comparison of hybrid nanomaterial, nanomaterials and regular liquid is expressed graphically. Outcomes indicate that the hybrid nanomaterials have great impact throughout the inspection than the ordinary nanomaterials.
Pregnancy Following Laparoscopy Guided Hysteroscopic Tubal Cannulation in Bilateral Tubal Block After Failed IVF Attempts
Authors: Siddiqui Maruf , Ghafoor Nusrat , Abdullah Rusmila Shamim , Naznine Fahmida , Mahajan Vinayak B.
Published: January 2021

Some infertile patients are diagnosed with unilateral or bilateral tubal block by hysterosalpingography (HSG). Laparoscopy is considered as the next step in its investigation and the tubes may be found patent in some of the cases confirming false positive for the HSG. Patients with confirmed bilateral tubal block (BLTB) have no option but to undergo in-vitro fertilization. IVF is a relatively expensive procedure. Many patients in Bangladesh are unable to proceed with repeated attempts if they fail to conceive in the first cycle. A significant proportion of these infertile women remain childless throughout their lives and become psychologically devastated. Laparoscopy guided hysteroscopic tubal cannulation can offer an alternative form of treatment in these groups of patients. Here we report a case in which BLTB was found both in HSG and laparoscopy. The patient then proceeded on to three unsuccessful embryo transfers. Following this, laparoscopy guided hysteroscopic tubal cannulation was performed and it was possible to successfully recanalize one tube. The patient became pregnant and delivered a healthy baby at term.
Measuring Information Systems Project Complexity: A Structural Equation Modelling Approach
Authors: Joseph Nazeer , Marnewick Carl
Published: January 2021

Complexity has emerged as the new norm in the 21st century, and IS projects play a significant role in organisations to address various socio‐political concerns. The purpose of this paper is to understand what are the relevant constructs for measuring IS project complexity. A model for measuring IS project complexity is developed using PLS‐SEM. The model reveals that organisational complexity, technical complexity, and uncertainty underpin IS project complexity. Organisational complexity in terms of project team, stakeholder management, and strategic drive should be managed by the project manager. Technical complexity was established in terms of project goals, requirements management, technology management, and norms and standards. Uncertainty in IS projects exists in terms of skills management, the triple constraint, and activity management. Suggestions were provided to guide IS project managers on how to manage each construct and alleviate the level of project complexity. This paper presents an updated and different perspective on measuring and managing IS project complexity. The findings would serve as additional building blocks to further elucidate IS project complexity understanding and assist with improving the value of these projects. Furthermore, the suggestions for IS project managers can lead discussions around how IS projects should be managed to ensure complexity is under control.
Method and Realization of Efficient Extraction of Basic Geological Data from Two‐Dimensional Mine Drawings
Authors: Lin Xiaobo
Published: January 2021

In coal mining technology systems, it is very important to acquire, store, and represent basic geological data comprehensively and accurately. Based on the current working mode and information level in mining geology at coal mines, this paper proposes a process of building basic geological database for modeling of coal mines by using existing results’ data of mining geology and develops the efficient program for getting the basic geological data from the important 2D plane drawings’ achievement at mines, such as the contour maps of mine coal seam floors, geological cross‐sections, underground drilling results, and geological survey results, based on AutoLISP, which is a programming language for the secondary development of AutoCAD. The obtained data in general text format is stored and managed by the MongoDB database, which realizes the storage, query, analysis, and correction of massive data of geological objects in the space of the underground coalmine. The application results show that compared with the previous data acquisition methods such as manual input and graphic transformation attribute, the extraction of spatial and attribute data from the existing mine 2D plane drawings by programming can effectively avoid the prominent problems such as artificial gross error, distortion of graph conversion, and different database structure, make the obtained spatial geological data more comprehensive, accurate, and effective, and, meanwhile, increase the rate by more than 60%, which plays an important role in data support for the construction of the geological modeling systems for transparent mines.
Dynamics and Control of Worm Epidemic Based on Mobile Networks by SEIQR-Type Model with Saturated Incidence Rate
Authors: Hu Rui , Gao Qingwu , Wang Bairong
Published: January 2021

The mobile networks have increasingly facilitated our daily life but are also breeding grounds for malicious worms, which are considered as the main threat to cyber security. The purpose of this paper is to analyze the dynamics of worm propagation and to control the worm epidemic based on mobile-phone networks. Accordingly, we establish an SEIQR-type model to explore the worm epidemic with saturated incidence rate. This paper shows that if the basic reproduction number is less than 1, the worm-free equilibrium is asymptotically stable, and the epidemic of worm will eventually disappear and remain under control; in addition, if the basic reproduction number is greater than 1, the asymptotical stability of worm-existence equilibrium is derived to imply that the epidemic will remain persistent and uncontrollable. Our results give new insights to mobile network security, namely, that is predicting the worm spreading tendency, identifying the epidemic control strategies, and estimating the worm popularity level. Numerical experiments are conducted to show the rationality of our obtained results and the effectiveness of the control strategies.
Establishment and Analysis of Spatiotemporal Variation Hydrological Model of Distributed Rainfall and Evaporation in Biliu River Basin
Authors: Liu Qi , Zhao Xiaolong , Wang Hongyan , Sun Yongfeng
Published: January 2021

The Biliu River originates from the southern foot of Qinling Mountain in Gaizhou city, with an elevation of 1047 m, and is the largest river in Dalian. The hydrological elements mainly include rainfall, runoff, temperature, evaporation, and other time series associated with the hydrological cycle. Among them, runoff is the most visible output performance, and the direct source of runoff is during rainfall. This paper establishes a reservoir scheduling model that considers the influence of multiple uncertainty factors and analyzes the influence of mixed uncertainty on reservoir scheduling and Xingli’s objectives based on probability box theory. In terms of uncertainties, the uncertainty of hydrological model parameters and the randomness of precipitation processes are mainly considered, with the former having an impact on river runoff simulation and the latter having an impact on both river runoff simulation and crop irrigation water demand. In the case of the Jing River basin, for example, the results show that, compared to the stochasticity of the precipitation process, the variation in precipitation has a significant effect on irrigation water demand in maize, followed by the frequency of precipitation, and the interaction between the two is not significant.
An Infeasible Incremental Bundle Method for Nonsmooth Optimization Problem Based on CVaR Portfolio
Authors: Li Jia-Tong , Shen Jie , Xu Na
Published: January 2021

For CVaR (conditional value‐at‐risk) portfolio nonsmooth optimization problem, we propose an infeasible incremental bundle method on the basis of the improvement function and the main idea of incremental method for solving convex finite min‐max problems. The presented algorithm only employs the information of the objective function and one component function of constraint functions to form the approximate model for improvement function. By introducing the aggregate technique, we keep the information of previous iterate points that may be deleted from bundle to overcome the difficulty of numerical computation and storage. Our algorithm does not enforce the feasibility of iterate points and the monotonicity of objective function, and the global convergence of the algorithm is established under mild conditions. Compared with the available results, our method loosens the requirements of computing the whole constraint function, which makes the algorithm easier to implement.
Effect of Stem Cell-Derived Extracellular Vesicles on Damaged Human Corneal Endothelial Cells
Authors: Nuzzi Raffaele , Buono Lola , Scalabrin Simona , De Iuliis Marco , Bussolati Benedetta
Published: January 2021

Purpose. Human corneal endothelial cells (HCECs) are essential to visual function; however, since they have limited proliferative capacity in vivo, they are prone to corneal endothelial dysfunction. At present, the only treatment is a corneal transplantation from donor cadavers. Also, due to a global shortage of donor corneas, it is important to find alternative strategies. Recent studies highlight that stem cell–derived extracellular vesicles (EVs) play a relevant role in stem cell-induced regeneration by reprogramming injured cells and inducing proregenerative pathways. The aim of this work is to evaluate whether EVs derived from mesenchymal stem cells (MSC-EVs) are able to promote regeneration of damaged HCECs. Methods. We isolated HCECs from discarded corneas in patients undergoing corneal transplantation or enucleation (

N
=
23

patients). Bone marrow mesenchymal stem cells (MSCs) were obtained from Lonza, cultured, and characterized. MSC-EVs were obtained from supernatants of MSCs. In order to establish a valid in vitro damage model to test the regenerative potential of EVs on HCECs, we evaluated the proliferation rate and the apoptosis after exposing the cells to serum-deprived medium at different concentrations for 24 hours. We then evaluated the HCEC migration through a wound healing assay. Results. In the selected serum deprivation damage conditions, the treatment with different doses of MSC-EVs resulted in a significantly higher proliferation rate of HCECs at all the tested concentrations of EVs (

5
‐
20
×

10

3

MSC-EV/cell). MSC-EVs/cell induced a significant decrease in number of total apoptotic cells after 24 hours of serum deprivation. Finally, the wound healing assay showed a significantly faster repair of the wound after HCEC treatment with MSC-EVs. Conclusions. Results highlight the already well-known proregenerative potential of MSC-EVs in a totally new biological model, the endothelium of the cornea. MSC-EVs, indeed, induced proliferation and survival of HCECs, promoting the migration of HCECs in vitro.
A Novel Method to Estimate the Sea State for Recycling Work on the Sea Surface
Authors: Zhang Haixu , Xu Xiaosu , Wang Guangcai , Zhu Yongyun
Published: January 2021

The recycling of marine exploration equipment after it has surfaced is greatly affected by sea state. In order to estimate the sea state in real time, this paper proposes a method for measuring wave elevation, which modifies the integrated results of GNSS/SINS in the up direction by virtual horizontal lines to extract wave fluctuation information. From these wave information, the significant wave heights (SWH) can be calculated as the only input parameter of P-M spectrum, and a series of wave height data can be further simulated. When the GNSS is interrupted due to severe sea state, the simulated data can be integrated with the SINS to deal with the data distortion problem. The simulation results show that the application of wave spectrum in the GNSS intermittent situation has obvious improvement effect and important significance.
Determining the Operator for the Public Toll Road
Authors: Shang Bin , Sun Qiang , Feng Hao , Chang Jiancong
Published: January 2021

After the BOT road operation contract expires, generally, the road will be transferred to the government, and then the government operates the road independently without charging costs from its users. Facing the huge amount of the operation cost, Chinese government tends to continue to charge the road users to guarantee the high quality of road operation. Then, the government will have to decide whether a private firm or government itself would be suitable to operate the road. A model is presented for decision-making through balancing interests between the government and the private firm with an introduction of an intermediate variable, i.e., bidding price. Three scenarios are investigated in the model, including the optimization of government operation, the optimization of private firm operation, and government operation with an improper decision of the intermediate variable. Improper intermediate variable will result in a higher toll charged by the government than by a private firm. The method of avoiding an improper decision is investigated. The result shows that the intermediate variable should be determined to be the government operation cost, based on which the private operator could be chosen, if available. With consideration of the private operator’s profit to be guaranteed by the government, the maximum subsidy should be equal to the minimum private operator’s profit to be disclosed when the contract is signed.
A Dynamic Intersecting Arrangement Model Based on Isolated Draw Zones for Stope Structure Optimization during Sublevel Caving Mining
Authors: Li Guanghui , Ren Fengyu , Ding Hangxing , Liu Huan , Sun Mingzhi , Li Guang
Published: January 2021

In this paper, stope structure optimization during sublevel caving mining is considered under the condition that the isolated draw zones (IDZs) are nonstandard ellipsoid, which is realized by dynamically adjusting the arrangement of IDZs and quantifying the degree of intersection of IDZs according to an ore profit and loss calculation model. A dynamic intersecting arrangement model based on IDZs was proposed, which can dynamically adjust the sublevel height and drift spacing according to the ore-rock bulk flow parameters, economic indicators, occurrence condition of the ore body, drilling machine, and so forth. Based on the model, the range of drift spacing, the lower volume of crestal residual ore, and the higher volume of mixing waste rock are calculated. By deducing the function of ore profit and loss, a calculation model for ore profit and loss is established to quantify the degree of intersection of IDZs and determine the best stope structure. Using the constructed dynamic intersecting arrangement model, a stope structure of −213 m to −303 m in the Yanqianshan Iron Mine was designed, with a sublevel height of 22.5 m and a drift spacing of 20.5 m. A physical drawing model was designed, and three physical simulation experiment schemes were conducted to compare and analyse the ore loss and dilution of the intersecting arrangement model and the traditional tangent arrangement model. The results showed that the loss rate decreased by 3.66% and the dilution rate increased by only 0.22%, thus verifying the effectiveness and applicability of the model to optimize the stope structure.