bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomechanical design analysis and experiments evaluation of a passive knee-assisting exoskeleton for weight-climbing
Authors: Li Bo , Yuan Bo , Tang Shuai , Mao Yuwen , Zhang Dongmei , Huang Changyun , Tan Bilian
Published: August 2018

Purpose

This paper aims to investigate weight-climbing assistance strategy for the biomechanical design of passive knee-assisting exoskeleton (PKAExo) and evaluate a designed PKAExo which stores energy when the knee joint flexes and releases the energy to assist ascending when the knee joint extends.

Design/methodology/approach

The authors constructed theoretic modeling of human weight-climbing to analyze characteristics of knee angle and moment. They then conducted camera-based movement analysis, muscle strength and endurance tests and surface electromyography (sEMG) measures to verify the relationship of knee angle and moment with both stair height and load weight. Afterwards, the authors proposed an assistant strategy for passive knee assistance, then gave out designed PKAExo and conducted mechanical experiment to test the knee-assisting torque. Finally, the authors conducted comparison experiment based on measuring the sEMG signals of knee extensor to verify the assistance effect of the PKAExo for weight-climbing.

Findings

The knee extensor produces the maximum force during weight-climbing, and the muscle force provided by knee extensor has significant increasing rate along with the stair height. Thus, the assistance torque of PKAExo is designed to increase nonlinearly along with increasing knee angle. It stores energy when knee flexes and assists when knee extends. Both the mechanical experiment and comparison experiment have demonstrated that the PKAExo is able to provide nonlinear assistance torque for weight-climbing, thus decreasing the average maximum load of knee extensor by about 21 per cent, reducing muscle fatigue and enhancing wearer’s weight-climbing ability.

Originality/value

The authors construct theoretic maximum force model produced by knee extensor for weight-climbing in static situation and conduct a series of experiments to verify and revise the model, which is the fundamental reference for knee-assisting mechanism designed for weight-climbing. The authors have also provided and validated an assistant strategy and the mechanism based on the biomechanical analysis, which aims to translate wearer’s energy-providing mode form high load to mid-low load by storing energy when knee flexes and assisting when knee extends. The PKAExo decreases the maximum load of knee extensor, reduces muscle fatigue and helps people to easily climb with load.
Does “clean” pay off? Housing markets and their perception of heating technology
Authors: Hahn Jonas , Hirsch Jens , Bienert Sven
Published: August 2018

Purpose

The purpose of this paper is to investigate the role of distinct types of heating technology and their price impact in German residential real estate markets, considering a wide range of other housing market determinants. The authors aim to test and to verify specifically, whether the obsolescence of heating technology leads to a significant price discount and whether higher technological standards (and environmental friendliness) come with a price premium on the market.

Design/methodology/approach

The authors create housing market models for rental and sales segments by constructing generalized additive models with explicit multi-layered spatial components. To elaborate a profound and contemporary answer using these models, the authors perform large-sample regression analyses based on more than 400,000 observations covering German residential properties in 2015.

Findings

First and foremost, the heating system indeed shows significant explanatory importance for measuring housing rents and purchasing price. Second, the authors find that it makes a difference whether clean “green” technologies are implemented or whether “brown” systems with obsolete technology or fossil energy sources is on hand. Ultimately, the authors conclude that while low energy consumption indeed comes with a price premium, this needs to be interpreted together with the property’s heating type, as housing markets seem to outweigh the “green premium” by “brown discounts” if low energy consumption figures are powered by a certain type of heating technology system.

Research limitations/implications

Aside of a possible omitted variable bias, the main research limitation is constituted by the integration of asking prices in the analysis, as actual transaction prices are not systematically transparent on national level in Germany. Limitations are discussed at the end of the paper.

Practical implications

This work supports investors who face the challenge of making environmental- and energy-related decisions as well as appraisers who deliver financial fundamentals for such. Third, the paper supports both asset managers as well as investment strategists in argumentation pro-environmental investments beyond all ecological necessity.

Social implications

This paper contributes to the current discussion on climate change and the eclectic role of real estate in this context. The authors deliver evidence on pricing effects as a measure of socioeconomic acceptance of progressive heating technology and environmental friendliness as an imperative of twenty-first century societies.

Originality/value

This is the first study on “green premiums” or “brown discounts” that includes heating technology as a potential and distinct driver of value and rents. It is a contemporary contribution and delivers original information on the quantitative impact of contemporary and anachronistic technology in heating to researchers as well as investors and appraisers.
Identification of crocin, crocetin and zeaxanthin in Crocus sativus grown under controlled environment in Malaysia
Authors: Anuar Nordiyanah , Taha Rosna Mat , Mahmad Noraini , Othman Rashidi
Published: August 2018

Purpose

The purpose of the study is to identify the high valuable compounds which are crocin, crocetin and zeaxanthin in the stigmas and stamens of Crocus sativus grown under controlled environment in Malaysia.

Design/methodology/approach

Spectrophotometry and high-performance liquid chromatography (HPLC) analysis were used to identify and measure crocin, crocetin and zeaxanthin content qualitatively and quantitatively in the stigmas and stamens of C. sativus grown under controlled environment in Malaysia.

Findings

The results of this study showed that crocin, crocetin and zeaxanthin were detected in the stigmas. However, among those three compounds, only crocetin was detected in the stamens. In the stigmas, the detectable level of crocin was high compared to crocetin and zeaxanthin. It was also found that crocetin was higher in the stamens compared to in the stigmas.

Originality/value

This is the first attempt in Malaysia that the stigmas and stamens were directly purified from the natural sources by means of no addition of preservatives as C. sativus has never been grown here before. Furthermore, limited reports are available regarding the identification of compounds in saffron stamens.
Experimental Investigations Into Nonlinear Vibro-Acoustics for Detection of Delaminations in a Composite Laminate
Authors: Singh Ashish Kumar , Tan Vincent B. C. , Tay Tong Earn , Lee Heow Pueh
Published: August 2018

In recent years, nonlinear vibro-acoustic methods have shown potential to identify defects which are difficult to detect using linear ultrasonic methods. However, these methods come with their own challenges such as frequency dependence, requirement for a high excitation amplitude, and difficulties in distinguishing nonlinearity from defect with nonlinearity from other sources to name a few. This paper aims to study the dependence of nonlinear vibro-acoustic methods for detection of delaminations inside a composite laminate, on the excitation methods and excitation frequencies. It is shown that nonlinear vibro-acoustic methods are highly frequency dependent and commonly used excitation signals which utilize particular values of excitation frequencies might not always lead to a clear distinction between intact and delaminated regions of the specimen. To overcome the frequency dependence, signals based on frequency sweep are used. Interpretation of output response to sweep signals to identify damage is demonstrated using an earlier available approach, and a simpler approach is proposed. It is demonstrated that the damage detection with sweep signal excitations is relatively less dependent on excitation frequency than the conventional excitation methods. The proposed interpretation technique is then applied to specimens with delamination of varying sizes and with delaminations at different depths inside the laminate to demonstrate its effectiveness.
Are Creativity and Self-Efficacy at Odds? An Exploration in Variations of Product Dissection in Engineering Education
Authors: Starkey Elizabeth M. , Hunter Samuel T. , Miller Scarlett R.
Published: August 2018

The purpose of product dissection is to teach students how a product works and provide them with inspiration for new ideas. However, little is known about how variations in dissection activities impact creative outcomes or engineering self-efficacy (ESE) and creative self-efficacies (CSE). This is important since the goal of engineering education is to produce capable and creative engineers. The current study was, thus, developed to address this research gap through a factorial experiment. The results showed that idea development was not impacted by dissection conditions but that ESE and CSE were increased through these activities. The results also showed that higher levels of CSE and ESE had alternate effects on novel idea development indicating they are at odds in engineering education.
A Note on the Induced Flow and Heat Transfer Due to a Deforming Cone Rotating in a Quiescent Fluid
Authors: Turkyilmazoglu Mustafa
Published: August 2018

This short brief is to address the boundary layer flow of motion due to a rotating as well as stretchable/shrinkable flexible cone in an otherwise still fluid. It is shown that the relevant information on the progress of the triggered boundary layer structure can be obtainable from the limiting traditional deformable rotating disk flow of von Karman, recently published in the literature. Thus, the physical parameters of great interest from the engineering point of view concerning a cone of a particular apex angle can be easily deduced as a multiplying factor corresponding to the deformable rotating disk flow.
Effect of Moisture Transfer Through a Semipermeable Membrane on Condensation/Frosting Limit
Authors: Niroomand S. , Fauchoux M. T. , Simonson C. J.
Published: August 2018

This paper investigates frost formation on a flat horizontal surface, with humid air flowing over the surface and a cold liquid desiccant flowing below the surface. Two different surfaces, a semipermeable membrane and an impermeable plate, are tested. The condensation/frosting limit, that is, the lowest air humidity ratio, Wair, at a constant liquid temperature, Tliq, or the highest Tliq at a constant Wair that leads to condensation/frosting, is determined for each surface. The main aim of this study is to find the effect of moisture transfer through the semipermeable membrane on the condensation/frosting limit. It is found that the semipermeable membrane has a lower condensation/frosting limit, due to the moisture transfer through the semipermeable membrane, which dehumidifies the air flow. For a given Wair, the surface temperature can be approximately 5 to 8 °C lower when using a semipermeable membrane, compared to an impermeable plate, before condensation/frosting occurs. Furthermore, it is shown that at some operating conditions, frost appears on the semipermeable membrane only at the air flow entrance of the test section, while the impermeable plate was fully covered with frost at the same operating conditions. Moreover, it is shown that increasing the moisture transfer rate through the semipermeable membrane decreases the frosting limit and delays frost formation.
Effect of the Bowl Structure in an Automated Cell-Isolation Device on Stromal Vascular Fraction's Isolation Yield
Authors: Hahn Hyung Min , Jeong Kwang Sik , Yoo Bo Young , Park Jong Ha , Jung Hyun Joo , Lee Il Jae
Published: August 2018

The enzymatic digestion of lipoaspirate is used to isolate the heterogeneous stromal vascular fraction (SVF) that contains the adipose-derived stromal cells (ASCs). Several automated SVF isolation systems are used to operate standard technical procedures and avoid human errors. However, the yield of isolated cells and the residual collagenase activities of the SVF samples obtained from automated systems are not satisfactory compared to those from manual isolation methods. In this study, we evaluated the efficiency and the reliability of a new automated SVF isolation system in which the bowl was designed in the shape of a radial protrusion at each angle (a top-type bowl). The viability and yield of cells and the residual collagenase activities of SVFs obtained in a top-type bowl were compared with the SVFs obtained in a conventional bowl. We achieved a significantly higher yield of cells and decreased residual collagenase activity in the SVFs obtained from a top-type bowl (18.0 × 105 cells/mL of fat) compared to a conventional bowl (2.3 × 105 cells/mL). There was no significant difference in the cell viability between the two groups. These results suggest that the automated SVF isolation system with an improved bowl structure will potentially yield higher numbers of nucleated cells and decreased residual collagenase activity compared to conventional automated systems in cell-based clinical trials.
Guided Waves as an Online Monitoring Technology for Long-Term Operation in Nuclear Power Plants: Experimental Results on a Steam Discharge Pipe
Authors: Cappelli Mauro , Cordella Francesco , Bertoncini Francesco , Raugi Marco
Published: August 2018

Guided wave (GW) testing is regularly used for finding defect locations through long-range screening using low-frequency waves (from 5 to 250 kHz). By using magnetostrictive sensors, some issues, which usually limit the application to nuclear power plants (NPPs), can be fixed. The authors have already shown the basic theoretical background and simulation results concerning a real steel pipe, used for steam discharge, with a complex structure. On the basis of such theoretical framework, a new campaign has been designed and developed on the same pipe, and the obtained experimental results are now here presented as a useful benchmark for the application of GWs as nondestructive techniques. Experimental measures using a symmetrical probe and a local probe in different configurations (pulse-echo and pitch-catch) indicate that GW testing with magnetostrictive sensors can be reliably applied to long-term monitoring of NPPs components.
Single-Motor Controlled Tendon-Driven Peristaltic Soft Origami Robot
Authors: Banerjee Hritwick , Pusalkar Neha , Ren Hongliang
Published: August 2018

Origami-based paper folding is being used in robotics community to provide stiffness and flexibility simultaneously while designing smart structures. In this paper, we propose a novel design inspired by origami pattern service robot, which transforms its shape in the axial direction and introduce peristaltic motion therein. Here, servo motor is being used for translational actuation and springs maneuver self-deployable structure when necessary. Self-deployable springs are compressed by the application of axial force as the string gets wound around the servo motor programed to rotate with a particular speed for specified time duration. Specially coated photopolymer resin structures have been used to provide external rigidity to the springs so to avoid buckling while operation. In future, this friction coated origami service robot is envisioned to be used in an unstructured environment as the scope of applications increases at the nexus of surgical robotic navigation, houses to disaster areas.
A Novel Active Rollover Prevention for Ground Vehicles Based on Continuous Roll Motion Detection
Authors: Wang Fengchen , Chen Yan
Published: August 2018

To enhance the performance of vehicle rollover detection and prevention, this paper proposes a novel control strategy integrating the mass-center-position (MCP) metric and the active rollover preventer (ARPer) system. The applied MCP metric can provide completed rollover information without saturation in the case of tire lift-off. Based on the continuous roll motion detection provided by the MCP metric, the proposed ARPer system can generate corrective control efforts independent to tire–road interactions. Moreover, the capability of the ARPer system is investigated for the given vehicle physical spatial constraints. A hierarchical control architecture is also designed for tracking desired accelerations derived from the MCP metric and allocating control efforts to the ARPer system and the active front steering (AFS) control. Cosimulations between CarSim® and MATLAB/SIMULINK with a fishhook maneuver are conducted to verify the control performance. The results show that the vehicle with the assistance of the ARPer system can successfully achieve better performance of vehicle rollover prevention, compared with an uncontrolled vehicle and an AFS-controlled vehicle.
A Model for Oil Flow and Fluid Temperature Inlet Mixing in Hydrodynamic Journal Bearings
Authors: Hagemann Thomas , Schwarze Hubert
Published: August 2018

The quality of predictions for the operating behavior of high-speed journal bearings strongly depends on realistic boundary conditions within the inlet region supplying a mixture of hot oil from the upstream pad and fresh lubricant from the inlet device to the downstream located pad. Therefore, an appropriate modeling of fundamental phenomena within the inlet region is essential for a reliable simulation of fluid and heat flow in the entire bearing. A theoretical model including hydraulic, mechanical, and energetic effects and the procedure of its numerical implementation in typical bearing codes for thermo-hydrodynamic lubrication is described and validated. Convective and conductive heat transfer as well as dissipation due to internal friction in the lubricant is considered for the space between pads or the pocket where the inlet is located. In contrast to most other models, the region between the physical inlet and the lubricant film is part of the solution domain and not only represented by boundary conditions. The model provides flow rate and temperature boundary conditions for extended Reynolds equation and a three-dimensional (3D) energy equation of film and inlet region, respectively. The impact of backflow from the inlet region to the outer supply channel possibly occurring in sealed pockets is taken into account. Moreover, the model considers the influence of turbulent flow in the inlet region.
The nonlinear ultrasound needle pulse
Authors: Ted Christopher P. , Parker Kevin J.
Published: August 2018

Recent work has established an analytical formulation of broadband fields which extend in the axial direction and converge to a narrow concentrated line. Those unique (needle) fields have their origins in an angular spectrum configuration in which the forward propagating wavenumber of the field (kz) is constant across any z plane for all of the propagated frequencies. A 3 MHz-based, finite amplitude distorted simulation of such a field is considered here in a water path scenario relevant to medical imaging. That nonlinear simulation had its focal features compared to those of a comparable Gaussian beam. The results suggest that the unique convergence of the needle pulse to a narrow but extended axial line in linear propagation is also inherited by higher harmonics in nonlinear propagation. Furthermore, the linear needle field's relatively short duration focal pulses, and the asymptotic declines of its radial profiles, also hold for the associated higher harmonics. Comparisons with the Gaussian field highlight some unique and potentially productive features of needle fields.
Differential Transmission of Antiviral Drug-Resistant Chikungunya Viruses by
Aedes
Mosquitoes
Authors: Delang Leen , Yen Pei-Shi , Vallet Thomas , Vazeille Marie , Vignuzzi Marco , Failloux Anna-Bella
Published: August 2018

Because of its global reemergence and unusual morbidities associated with infection, the chikungunya virus (CHIKV) has become a substantial public health problem. However, no antivirals are currently available to treat CHIKV infections. If antiviral drugs will prove to be efficient to treat CHIKV-infected patients, it will be essential to understand if drug-resistant viruses can be transmitted from one human to another by the mosquito. We therefore orally infected
Aedes
mosquitoes with drug-resistant CHIKV variants and determined the replication and transmission levels. One of the antiviral drug-resistant CHIKV variants could efficiently replicate and disseminate in both laboratory and field-collected mosquitoes. In addition, this variant retained its drug-resistant genotype in the saliva. In contrast, the other drug-resistant variant was markedly attenuated in mosquitoes. Our results illustrate that extra caution for drug resistance should be considered when developing an antiarbovirus antiviral in order to minimize the risk of spreading drug resistance by mosquitoes.
How events in emergency medicine impact doctors’ psychological well-being
Authors: Howard Laura , Wibberley Christopher , Crowe Liz , Body Richard
Published: August 2018

Background

Emergency medicine is a high-pressured specialty with exposure to disturbing events and risk. We conducted a qualitative study to identify which clinical events resulted in emotional disruption and the impact of these events on the well-being of physicians working in an ED.

Methods

We used the principles of naturalistic inquiry to conduct narrative interviews with physicians working in the ED at Central Manchester University Hospitals NHS Foundation Trust, between September and October 2016. Participants were asked, ‘Could you tell me about a time when an event at work has continued to play on your mind after the shift in which it occurred was over?’ Data were analysed using framework analysis. The study had three a priori themes reported here. Other emergent themes were analysed separately.

Results

We interviewed 17 participants. Within the first a priori theme (‘clinical events’) factors associated with emotional disruption included young or traumatic deaths, patients or situations that physicians could relate to, witnessing the impact of death on relatives, the burden of responsibility (including medical error) and conflict in the workplace. Under theme 2 (psychological and physical effects), participants reported substantial upset leading to substance misuse, sleep disruption and neglecting their own physical needs through preoccupation with caring. Within theme 3 (impact on relationships), many interviewees described becoming withdrawn from personal relationships following clinical events, while others described feeling isolated because friends and family were non-medical.

Conclusions

Clinical events encountered in the ED can affect a physician’s psychological and physical well-being. For many participants these effects were negative and long lasting.
Enterocolitis due to immune checkpoint inhibitors: a systematic review
Authors: Soularue Emilie , Lepage Patricia , Colombel Jean Frederic , Coutzac Clelia , Faleck David , Marthey Lysiane , Collins Michael , Chaput Nathalie , Robert Caroline , Carbonnel Franck
Published: August 2018

Immune checkpoint inhibitors targeting cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) and programmed death-1 (PD-1)/ligand are increasingly used to treat several types of cancer. These drugs enhance antitumour T-cell activity and therefore induce immune-related adverse effects (irAE), of which gastrointestinal (GI) irAE are among the most frequent and severe. This systematic literature review summarises the clinical manifestations, management and pathophysiology of GI irAE due to immune checkpoint inhibitors. GI irAE induced by anti-CTLA-4 are frequent, potentially severe and resemble IBD, whereas those induced by PD-1 blockade seem to be less frequent and clinically more diverse. Baseline symbiotic gut microbiota is associated with an enhanced antitumour response to immune checkpoint inhibitors and an increased susceptibility to developing enterocolitis, in patients treated with anti-CTLA-4. These findings open new perspectives for possible manipulation of the gut microbiota in order to better identify responders to immune checkpoint inhibitors and to increase their efficacy and safety.
Inter- and intraobserver reliability for angiographic leptomeningeal collateral flow assessment by the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) scale
Authors: Ben Hassen Wagih , Malley Claire , Boulouis Grégoire , Clarençon Frédéric , Bartolini Bruno , Bourcier Romain , Rodriguez Régent Christine , Bricout Nicolas , Labeyrie Marc Antoine , Gentric Jean Christophe , Rouchaud Aymeric , Soize Sébastien , Saleme Suzana , Raoult Hélène , Gallas Sophie , Eugène François , Anxionnat René , Herbreteau Denis , Bracard Serge , Naggara Olivier
Published: August 2018

Background

The adequacy of leptomeningeal collateral flow has a pivotal role in determining clinical outcome in acute ischemic stroke. The American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) collateral score is among the most commonly used scales for measuring this flow. It is based on the extent and rate of retrograde collateral flow to the impaired territory on angiography.

Objective

To evaluate inter- and intraobserver agreementin angiographic leptomeningeal collateral flow assessment.

Materials and methods

Thirty pretreatment angiogram video loops (frontal and lateral view), chosen from the randomized controlled trial THRombectomie des Artères CErebrales (THRACE), were sent for grading in an electronic file. 19 readers participated, including eight who had access to a training set before the first grading. 13 readers made a double evaluation, 3 months apart.

Results

Overall agreement among the 19 observers was poor (κ = 0,16 ± 6,5.10-3), and not improved with prior training (κ = 0,14 ± 0,016). Grade 4 showed the poorest interobserver agreement (κ=0.18±0.002) while grades 0 and 1 were associated with the best results (κ=0.52±0.001 and κ=0.43±0.004, respectively). Interobserver agreement increased (κ = 0,27± 0,014) when a dichotomized score, ‘poor collaterals’ (score of 0, 1 or 2) versus ‘good collaterals’ (score of 3 or 4) was used. The intraobserver agreements varied between slight (κ=0.18±0.13) and substantial (κ=0.74±0.1), and were slightly improved with the dichotomized score (from κ=0.19±0.2 to κ=0.79±0.11).

Conclusion

Inter- and intraobserver agreement of collateral circulation grading using the ASITN/SIR score was poor, raising concerns about comparisons among publications. A simplified dichotomized judgment may be a more reproducible assessment when images are rated by the same observer(s) in randomized trials.
PMI’s own in vivo clinical data on biomarkers of potential harm in Americans show that IQOS is not detectably different from conventional cigarettes
Authors: Glantz Stanton A
Published: August 2018

Introduction

New ‘heated tobacco products’ are being marketed in several countries with claims that they expose users to lower levels of toxins than conventional cigarettes which could be read as being less likely to cause health problems than conventional cigarettes. In the USA, Philip Morris International (PMI) has submitted an application to the Food and Drug Administration for permission to market its heated tobacco product, IQOS, with reduced exposure and reduced risk claims.

Methods

Analysis of detailed results on 24 biomarkers of potential harm in PMI studies of humans using IQOS compared with humans using conventional cigarettes.

Results

Among American adults, there is no statistically detectable difference between IQOS and conventional cigarette users for 23 of the 24 biomarkers of potential harm in PMI’s studies. In Japan, there were no significant differences between people using IQOS and conventional cigarettes in 10 of 13 biomarkers of potential harm. It is likely that some of the significant differences are false positives.

Conclusion

Despite delivering lower levels of some toxins than conventional cigarettes, PMI’s own data fail to show consistently lower risks of harm in humans using its heated tobacco product, IQOS, than conventional cigarettes.
Load model for designing flexible steel barriers for debris flow mitigation
Authors: Wendeler Corinna , Volkwein Axel , McArdell Brian W. , Bartelt Perry
Published: August 2018

Light-weight flexible steel net barriers catch coarse debris, but let some of the fine material and water pass through the net. They are difficult to design so that they can withstand the impact pressures of both boulder-laden granular and water-saturated debris flows. Using results from laboratory and full-scale field tests, a debris flow load model has been developed for flexible barriers in torrent channels. The model accounts for the forces of initial impact as well as the filling process discretized stepwise over time (barriers in the field and laboratory fill continuously). Laboratory tests with fast debris flow front velocities revealed a run-up behaviour that was not observed in the field (“pile-up”). The load model divides the flow forces into a hydrostatic component and a dynamic part depending on a pressure coefficient, the flow velocity, and the density of the flow. This dynamic part, which is more complex to quantify, accounts for the wide-ranging debris flow characteristics from watery and muddy debris floods to granular friction-dominated mass flows.
Controlled heavy-haul traffic loading as a method to remediate liquefiable soft silts
Authors: Krechowiecki-Shaw C.J. , Royal A.C.D. , Jefferson I.
Published: August 2018

Transporting of extremely large indivisible loads (10 000–30 000 t) is becoming increasingly popular to allow offsite modular construction of infrastructure for oil and gas, mining, and renewable energy projects in remote areas. Such exceptionally large transient loads could encounter unusual geohazards: there is a risk of metastable liquefaction when crossing soft alluvium, causing sudden failure, potential casualties, and severe production delays. Furthermore, temporary roads for these payloads are a large cost to such projects; conventionally designed earthworks and (or) ground improvement are often unaffordable or logistically impossible. This laboratory study indicates the fabric can be strengthened, and the hazard reduced, if the soil is subjected to careful repeated loading that rearranges the initially precarious fabric through gradual accumulation of plastic strains. A novel remediation technique for these temporary haul roads is proposed: managed deployment of increasingly heavy haul vehicles could result in staged fabric rearrangement that strengthens the soil to the point where it would be safe for the heavy vehicles to use it. In so doing, a more economic temporary haul road is open to operations (coupled with observation methods to ensure adequate performance throughout) and production activities are not overly disrupted.
Operations on Unambiguous Finite Automata
Authors: Jirásek Jozef , Jirásková Galina , Šebej Juraj
Published: August 2018

A nondeterministic finite automaton is unambiguous if it has at most one accepting computation on every input string. We investigate the state complexity of basic regular operations on languages represented by unambiguous finite automata. We get tight upper bounds for reversal ([Formula: see text]), intersection ([Formula: see text]), left and right quotients ([Formula: see text]), positive closure ([Formula: see text]), star ([Formula: see text]), shuffle ([Formula: see text]), and concatenation ([Formula: see text]). To prove tightness, we use a binary alphabet for intersection and left and right quotients, a ternary alphabet for star and positive closure, a five-letter alphabet for shuffle, and a seven-letter alphabet for concatenation. For complementation, we reduce the trivial upper bound [Formula: see text] to [Formula: see text]. We also get some partial results for union and square.
Compositions of Tree-to-Tree Statistical Machine Translation Models
Authors: Maletti Andreas
Published: August 2018

The well-known synchronous context-free grammars (SCFGs) and synchronous tree-substitution grammars (STSGs), both of which are used as tree-to-tree translation models in statistical machine translation are investigated. Their composition hierarchies are established in both the unweighted as well as the weighted case. More precisely, it is shown that SCFGs are closed under composition in both cases and that there is a close connection between compositions of STSGs and compositions of certain tree transducers. With the help of the close ties, the composition closure of STSGs is identified in both cases as well. The results for the weighted case utilize a new lifting technique that might prove useful also in similar setups.
Beyond anyons
Authors: Wang Zhenghan
Published: August 2018

The theory of anyon systems, as modular functors topologically and unitary modular tensor categories algebraically, is mature. To go beyond anyons, our first step is the interplay of anyons with conventional group symmetry due to the paramount importance of group symmetry in physics. This led to the theory of symmetry-enriched topological order. Another direction is the boundary physics of topological phases, both gapless as in the fractional quantum Hall physics and gapped as in the toric code. A more speculative and interesting direction is the study of Banados–Teitelboim–Zanelli (BTZ) black holes and quantum gravity in 3d. The clearly defined physical and mathematical issues require a far-reaching generalization of anyons and seem to be within reach. In this short survey, I will first cover the extensions of anyon theory to symmetry defects and gapped boundaries. Then, I will discuss a desired generalization of anyons to anyon-like objects — the BTZ black holes — in 3d quantum gravity.
Charm, bottom, strange baryon masses using QCD sum rules
Authors: Kisslinger Leonard S. , Singha Bijit
Published: August 2018

We use the method of QCD sum rules to estimate the masses of the charm baryon, [Formula: see text], bottom baryon [Formula: see text], strange baryon [Formula: see text] and compare them to their experimental values.
Ensemble Classification for Skewed Data Streams Based on Neural Network
Authors: Zhang Yong , Yu Jiaxin , Liu Wenzhe , Ota Kaoru
Published: August 2018

Data stream learning in non-stationary environments and skewed class distributions has been receiving more attention in machine learning communities. This paper proposes a novel ensemble classification method (ECSDS) for classifying data streams with skewed class distributions. In the proposed ensemble method, back-propagation neural network is selected as the base classifier. In order to demonstrate the effectiveness of our proposed method, we choose three baseline methods based on ECSDS and evaluate their overall performance on ten datasets from UCI machine learning repository. Moreover, the performance of incremental learning is also evaluated by these datasets. The experimental results show our proposed method can effectively deal with classification problems on non-stationary data streams with class imbalance.
Nonlinear Whirling Motion of Monopile Offshore Wind Turbines Subjected to Harmonic and Seismic Base Excitations
Authors: Cai Zhicheng , Zheng Xiang Yuan
Published: August 2018

The triggering mechanism and the vibration patterns of the nonlinear whirling motion of monopile offshore wind turbines subjected to unidirectional base excitations are investigated both theoretically and experimentally via a 64:1 scaled model of the prototype NREL-5MW monopile offshore wind turbine. For motion, two nonlinear coupled integro-differential equations containing cubic nonlinearities due to curvature and inertia are solved by both analytical and numerical methods. Harmonic and random seismic base excitations with different amplitudes and frequencies are considered in the analysis to understand the instability mechanism. Extensive shake table tests show that the experimental results have good qualitative agreements with the theoretical results, and as observed in eight load cases, the nonlinear whirling motions of nacelle do exist and tend to be induced by large harmonic excitations with structural resonant frequency.
Generalized Second Moment of Areas of Regular Polygons for Ludwick Type Material and its Application to Cantilever Column Buckling
Authors: Lee Joon Kyu , Lee Byoung Koo
Published: August 2018

This study deals with the generalized second moment of area (GSMA) of regular polygon cross-sections for the Ludwick type material and its application to cantilever column buckling. In the literature, the GSMA for the Ludwick type material has only been considered for rectangular, elliptical and superellipsoidal cross-sections. This study calculates the GSMAs of regular polygon cross-sections other than those mentioned above. The GSMAs calculated by varying the mechanical constant of the Ludwick type material for the equilateral triangle, square, regular pentagon, regular hexagon and circular cross-sections are reported in tables and figures. The GSMAs obtained from this study are applied to cantilever column buckling, with results shown in tables and figures.
A Study on Determining the Relationships Among Corporate Social Responsibility, Organizational Citizenship Behavior and Ethical Leadership
Authors: Cingöz Ayşe , Akdoğan A. Asuman
Published: August 2018

Corporate social responsibility (CSR) has emerged as a prominent term in management literature. CSR refers to the extent to which businesses meet the economic, legal, ethical, and discretionary responsibilities imposed on them by their stakeholders. CSR is suggested to have a positive effect on employees’ organizational citizenship behavior (OCB). Also, managers are likely to perform ethical behaviors in their leadership roles when management supports CSR initiatives. In this study, we examined the relationship among CSR, OCB and ethical leadership using a sample of 60 employees from Nevşehir(Cappadocia-Turkey). Our findings indicate a significant and positive relationship between CSR and ethical leadership. However, no significant relationship was found either between OCB and CSR, nor OCB and ethical leadership.
THE ROLE OF PLANS IN THE FORMATION OF A NEW INNOVATION PRACTICE: AN INNOVATION OBJECT PERSPECTIVE
Authors: FOSSTENLØKKEN SIW M.
Published: August 2018

This paper explores the role of plans, as objects, in the formation of new innovation practice in organisations. A vocabulary for analysis is developed from innovation object theory. First, findings from an ethnographic study in a hospital organisation show that a plan serves several functions depending on its activation for use: a checklist of past practice (tertiary object), an opener for debates over current practice (secondary object) and a trigger for future practice development (primary object). Second, a framework is offered that shows how a plan supports different functionalities (evaluating, debating, further exploring) in a temporal dynamics of practice formation. Third, thus, plans play a significant role not only in planning activities, but also as connectors that shape and patch together pieces of past, present and future into what actually become new organisational practice. Finally, implications for innovation theory and management are drawn from these novel contributions.
Hydrogen Sorption of Porous Tungsten Oxide Nanomaterial and Effect of a Pd Coating on its Storage Capacity Under Hydrogenation Cycles
Authors: Diaz-Droguett D. E. , Rojas S. , Roble M.
Published: August 2018

The H2 uptake performance at room temperature of porous tungsten oxide nanomaterials with and without a catalytic Pd coating was studied by the quartz crystal microbalance technique. Tungsten oxide composed mainly of WO3 was synthesized by inert gas condensation method using He. The samples consisted of semi-amorphous nanomaterials of low crystallinity and high porosity, as revealed by SAED, TEM, XRD, Raman spectroscopy and N2 adsorption–desorption isotherms. The H2 uptake capacity of the porous oxide was studied under increasing H2 exposure pressures (1000–7000[Formula: see text]Pa), with and without Pd coating. After reaching a maximum value of 1.2 H2[Formula: see text]wt.%, at 1160[Formula: see text]Pa, the H2 uptake capacity of the Pd-coated oxide consistently decreased. Successive hydrogenation cycles were carried out on the Pd-coated oxide at 3300 Pa and 6000 Pa to evaluate the H2 uptake performance of the sample under this H2 loading and unloading process. It was found that the H2 uptake capacity decreased from around 1 to values below 0.53[Formula: see text]H2[Formula: see text]wt.%, which is the reference H2 storage capacity achieved by a 15[Formula: see text]nm-thick Pd film. We argued that water molecule formation in the Pd/oxide interface and sublayers negatively affects the H2 uptake capacity of the oxide under successive hydrogenation cycles at room temperature.
Almost periodic dynamics of delayed prey–predator model with discontinuous harvesting policies and Hassell–Varley type functional response
Authors: Chen Dongxiao , Wang Dongshu
Published: August 2018

In this study, a class of delayed prey–predator model with Hassell–Varley type functional response is investigated, in which the harvesting policies are modeled by discontinuous functions. Based on functional differential inclusions and set-valued analysis theories, the local and global existence of positive solution in sense of Filippov is given. By employing theory of functional differential inclusions and generalized differential inequalities, some sufficient conditions which guarantee the permanence of the system are obtained. According to non-smooth analysis theory with generalized Lyapunov functional approach, a series of useful criteria on existence, uniqueness and global asymptotic stability of the almost positive periodic solution to the system are derived. Some suitable examples together with their numerical simulations are given to illustrate the effectiveness of our results by using MATLAB.
Gradient flow line near birth–death critical points
Authors: Antony Charel
Published: August 2018

Near a birth–death critical point in a one-parameter family of gradient flows, there are precisely two Morse critical points of index difference one on the birth side. This paper gives a self-contained proof of the folklore theorem that these two critical points are joined by a unique gradient trajectory up to time-shift. The proof is based on the Whitney normal form, a Conley index construction, and an adiabatic limit analysis for an associated fast–slow differential equation.
On splitting rank of non-compact-type symmetric spaces and bounded cohomology
Authors: Wang Shi
Published: August 2018

Let [Formula: see text] be a higher rank symmetric space of non-compact type where [Formula: see text]. We define the splitting rank of [Formula: see text], denoted by [Formula: see text], to be the maximal dimension of a totally geodesic submanifold [Formula: see text] which splits off an isometric [Formula: see text]-factor. We compute explicitly the splitting rank for each irreducible symmetric space. For an arbitrary (not necessarily irreducible) symmetric space, we show that the comparison map [Formula: see text] is surjective in degrees [Formula: see text], provided [Formula: see text] has no direct factors of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]. This generalizes the result of [J.-F. Lafont and S. Wang, Barycentric straightening and bounded cohomology, to appear in J. Eur. Math. Soc.] regarding Dupont’s problem.
On the topological complexity of aspherical spaces
Authors: Farber Michael , Mescher Stephan
Published: August 2018

The well-known theorem of Eilenberg and Ganea [Ann. Math. 65 (1957) 517–518] expresses the Lusternik–Schnirelmann category of an Eilenberg–MacLane space [Formula: see text] as the cohomological dimension of the group [Formula: see text]. In this paper, we study a similar problem of determining algebraically the topological complexity of the Eilenberg–MacLane spaces [Formula: see text]. One of our main results states that in the case when the group [Formula: see text] is hyperbolic in the sense of Gromov, the topological complexity [Formula: see text] either equals or is by one larger than the cohomological dimension of [Formula: see text]. We approach the problem by studying essential cohomology classes, i.e. classes which can be obtained from the powers of the canonical class (as defined by Costa and Farber) via coefficient homomorphisms. We describe a spectral sequence which allows to specify a full set of obstructions for a cohomology class to be essential. In the case of a hyperbolic group, we establish a vanishing property of this spectral sequence which leads to the main result.
3-Paintability of planar graphs
Authors: Yan Huihui , Qi Hao
Published: August 2018

This paper proves that if [Formula: see text] is a planar graph without cycles of length [Formula: see text] to [Formula: see text], with triangles having distance at least two and contains no special configurations, then [Formula: see text] is [Formula: see text]-paintable (and hence is [Formula: see text]-choosable).
Bounding execution resources for the task scheduling problem in cyber-physical systems
Authors: Rădulescu Vlad , Andrei Ştefan , Cheng Albert M. K.
Published: August 2018

In designing and analyzing real-time systems, the central problem resides in finding a feasible schedule for a given task set, if one exists. A lot of research effort has been carried out in approaching the various aspects of task scheduling. While most results have been achieved for preemptive scheduling, the non-preemptive case has still room for improvement, due to its complexity. In addition, the widespread usage of cyber-physical systems (CPS) is putting real-time scheduling in the position to deal with new challenges, as additional (and sometimes particular) requirements are raised by such systems.

This paper, which continues the previous work of the authors, introduces a new lower bound on the number of processing units that allows a feasible schedule of a task set for both preemptive and non-preemptive scheduling. As a specific CPS issue, the necessity of moving the processing units in space, which incurs additional time requirements, is considered. The single-instance case is first discussed, then the results are extended to the periodic case.
Stapes Surgery for Otosclerosis in Patients Presenting with Mixed Hearing Loss
Authors: Salmon Caroline , Barriat Sébastien , Lefebvre Philippe P.
Published: August 2018

Objectives: To evaluate the efficacy of stapes surgery in patients presenting with a preoperative mixed hearing loss (bone conduction thresholds ≥40 dB; 40 < air conduction thresholds (AC) < 85 dB). Patients and Methods: A total of 30 patients (32 ears) with mixed hearing loss who underwent primary stapedotomy were evaluated. Audiometric parameters were assessed before and after surgery. Contralateral thresholds were also reported. The need for a hearing aid (HA) after surgery and its impact on quality of life were also measured. Results: AC and word recognition at 40, 55 and 70 dB were significantly improved after stapes surgery. Only 16.6% of the patients needed an HA after surgery and reported being satisfied with the aid. Conclusion: Stapes surgery improved auditory function in patients with mixed hearing loss, allowing most patients to delay the need for an HA without worsening their quality of life.