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1
Koňas, Petr, and Eva Přemyslovská. "General model of wood in typical coupled tasks, Part II. – Weak solution." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 56, no. 4 (2008): 103–8. http://dx.doi.org/10.11118/actaun200856040103.
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The main aim of this work is focused on weak solution of coupled physical task the microwave drying of wood with stress-strain effects and moisture/temperature dependency. Due to well known weak solution for separated physical fields without coupled effect, author concerns with coupled stress-strain relation coupled with moisture and temperature distribution. For scale dependency the subgrid upscaling method was used. Solved region is assumed to be divided into discontinual subregions according to investigated scale. This approach sugests sequential type of solution for highly coupled task. This way, very huge structures (huge according to geometry and also physics) can be solved in reasonable time and with memory consumptions. Main emphasis was putted on evaluation of structural response of the whole complex. Due to influence of moisture, temperature and time the coupled physical task of structural response is solved. Sugested aproach is of course usable not only for structural response, but for other physical fields, which were taken into account. Weak solution is based on slightly modified Ritz-Galerkin method. The work is continuing of the previous article General model of wood in typical coupled tasks: Part I. – Phenomenological approach.
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Papadrakakis, M., N. D. Lagaros, and V. Plevris. "Structural optimization considering the probabilistic system response." Theoretical and Applied Mechanics 31, no. 3-4 (2004): 361–94. http://dx.doi.org/10.2298/tam0404361p.
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In engineering problems, the randomness and uncertainties are inherent and the scatter of structural parameters from their nominal ideal values is unavoidable. In Reliability Based Design Optimization (RBDO) and Robust Design Optimization (RDO) the uncertainties play a dominant role in the formulation of the structural optimization problem. In an RBDO problem additional non deterministic constraint functions are considered while an RDO formulation leads to designs with a state of robustness, so that their performance is the least sensitive to the variability of the uncertain variables. In the first part of this study a metamodel assisted RBDO methodology is examined for large scale structural systems. In the second part an RDO structural problem is considered. The task of robust design optimization of structures is formulated as a multi-criteria optimization problem, in which the design variables of the optimization problem, together with other design parameters such as the modulus of elasticity and the yield stress are considered as random variables with a mean value equal to their nominal value. .
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Zapała, Dariusz, Emilia Zabielska-Mendyk, Andrzej Cudo, Marta Jaśkiewicz, Marcin Kwiatkowski, and Agnieszka Kwiatkowska. "The Role of Motor Imagery in Predicting Motor Skills in Young Male Soccer Players." International Journal of Environmental Research and Public Health 18, no. 12 (June 10, 2021): 6316. http://dx.doi.org/10.3390/ijerph18126316.
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The study aimed to find out whether the imagery ability within the two subcomponents of motor imagery (visual and kinesthetic) allows predicting the results in simple response time task and eye–hand coordination task in a group of young male soccer players (9–15 years old). Non-specific simple response time and eye–hand coordination play a key role in predicting specific sports performance level. Participants performed Reaction Time Task, Eye–Hand Coordination Task, and completed Motor Imagery Questionnaire–Revised. Data were submitted to the structural equations analysis based on the maximum likelihood method in order to estimate a structural model of relationship between variables. Results indicate visual rather than kinesthetic motor imagery is associated with non-specific motor skills. Higher scores on the visual motor imagery scale were observed to correlate with faster reaction times and better coordination in the study group. This supports the idea that during learning a new perceptual-motor-task the visual control is required. Results provide the evidence for the specific role of the third-person perspective imagery in young athletes playing soccer.
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Ou, Yaowen, Eleni N. Chatzi, Vasilis K. Dertimanis, and Minas D. Spiridonakos. "Vibration-based experimental damage detection of a small-scale wind turbine blade." Structural Health Monitoring 16, no. 1 (September 24, 2016): 79–96. http://dx.doi.org/10.1177/1475921716663876.
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Structural health monitoring offers an attractive tool for condition assessment, fault prognosis and life-cycle management of wind turbine components. However, owing to the intense loading conditions, geometrical nonlinearities, complex material properties and the lack of real-time information on induced structural response, damage detection and characterization of structural components comprise a challenging task. This study is focused on the problem of damage detection for a small-scale wind turbine (Sonkyo Energy Windspot 3.5 kW) experimental blade. To this end, the blade is dynamically tested in both its nominal (healthy) condition and for artificially induced damage of varying types and intensities. The response is monitored via a set of accelerometers; the acquired signals serve for damage detection via the use of appropriate statistical and modal damage detection methods. The former rely on extraction of a characteristic statistical quantity and establishment of an associated statistical hypothesis test, while the latter rely on tracking of damage-sensitive variations of modal properties. The results indicate that statistical-based methods outperform modal-based ones, succeeding in the detection of induced damage, even at low levels.
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Sadhu, Ayan, Sandeep Sony, and Peter Friesen. "Evaluation of progressive damage in structures using tensor decomposition-based wavelet analysis." Journal of Vibration and Control 25, no. 19-20 (July 11, 2019): 2595–610. http://dx.doi.org/10.1177/1077546319861878.
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Effective monitoring and retrofitting of large-scale infrastructure subjected to natural hazards such as strong wind, severe earthquakes or man-made excitation are critical to ensure structural integrity and prevent any premature failure. With the aid of structural health monitoring, it is now possible to acquire rich vibration data, estimate the hidden structural information, and evaluate the existing structural performance. The nonstationary component of vibration response resulting from natural hazards poses difficulty in analysis using traditional modal identification methods that are based on the stationarity assumption of vibration response. Apart from the excitation-induced nonstationarity, inherent damages in the structure also cause frequency-dependent nonstationarity in the response. With such a combination of both amplitude and frequency-dependent nonstationary response, the modal identification becomes a significantly challenging task. In this paper, Cauchy continuous wavelet transform is integrated with the tensor decomposition to track time-varying characteristics of modal responses and detect any progressive damage. The proposed technique is validated using a suite of numerical studies as well as a laboratory experiment where the progressive damage is simulated in the members by heating them using a butane torch. Unlike detection of discrete damage, the proposed method is one of introductory approaches to assess progressive damage in structures.
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Attari, N. K. A., F. R. Rofooei, and Z. Waezi. "On nonlinear perturbation analysis of a structure carrying a circular cylindrical liquid tank under horizontal excitation." Journal of Vibration and Control 25, no. 5 (November 14, 2018): 1058–79. http://dx.doi.org/10.1177/1077546318810072.
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The lateral response of a single degree of freedom structural system containing a rigid circular cylindrical liquid tank under harmonic and earthquake excitations at a 1:2 autoparametric resonance case is considered. The governing nonlinear differential equations of motion for the combined system are solved by means of a multiple scales method considering the first three liquid sloshing modes (1,1), (0,1), and (2,1), under horizontal excitation. The fixed points of the gyroscopic type of governing differential equations are determined and their stability is investigated employing the perturbation method. The obtained results reveal an increase in the stability region for a single-mode response with respect to the excitation amplitude. The saturation phenomenon is observed in the decoupled modes of the system; however, the structural mode and the first anti-symmetric mode of liquid are a combination of the saturated mode and another mode whose scale factor is crucial for the structural response. The results of perturbation analysis are in good agreement with results obtained from numerical methods.
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Yew, Guo Zheng, M. S. Liew, Mohd Shahir Liew, and Cheng Yee Ng. "System Identification of a Six-Legged Semisubmersible Subjected to Wave Loads through Frequency Domain Analysis." Applied Mechanics and Materials 373-375 (August 2013): 770–84. http://dx.doi.org/10.4028/www.scientific.net/amm.373-375.770.
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Sea state conditions such as wind, wave and current vary in different ocean waters. Two similar offshore structures installed in two different ocean regions will yield different responses. Determining the transfer function of the structure is a system identification exercise that yields the structural response and behaviour given any sea state condition. The transfer function can be determined using available measured sea state data and structural response data. In this paper, a six-legged semisubmersible physical model is developed to a scale of 1:100 and is tested in a wave tank to measure its responses due to simulated random wave loads. The transfer functions of the semisubmersible model are then determined using the measured responses and the measured wave heights.
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Miller, Kimberly J., Courtney L. Pollock, Brenda Brouwer, and S. Jayne Garland. "Use of Rasch Analysis to Evaluate and Refine the Community Balance and Mobility Scale for Use in Ambulatory Community-Dwelling Adults Following Stroke." Physical Therapy 96, no. 10 (October 1, 2016): 1648–57. http://dx.doi.org/10.2522/ptj.20150423.
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AbstractBackgroundThe Community Balance and Mobility Scale (CB&M) is increasingly used to evaluate walking balance following stroke.ObjectiveThis study applied Rasch analysis to evaluate and refine the CB&M for use in ambulatory community-dwelling adults following stroke.MethodsThe CB&M content was linked to task demands and motor skill classifications. Rasch analysis was used to evaluate internal construct validity (structural validity) and refine the CB&M for use with ambulatory community-dwelling adults following stroke. The CB&M data were collected at 3 time points: at discharge from inpatient rehabilitation and at 6 and 12 months postdischarge (N=238). Rasch analysis evaluated scale dimensionality, item and person fit, item response bias, scoring hierarchy, and targeting. Disordered scoring hierarchy was resolved by collapsing scoring categories. Highly correlated and “misfitting” items were removed. Sensitivity to change was evaluated with standardized response means (SRMs) and one-way repeated-measures analysis of variance.ResultsThe CB&M was primarily linked to closed body transport task demands. Significant item-trait interaction, disordered scoring hierarchies, and multidimensionality were found. Scoring categories were collapsed in 15/19 items, and 5 misfitting items were removed. The resulting stroke-specific 14-item unidimensional CB&M (CB&MStroke) fit Rasch model expectations, with no item response bias, acceptable targeting (13% floor effects and 0% ceiling effects), and moderate-to-strong sensitivity to change at 6 months postdischarge (SRM=0.63; 95% confidence interval=−1.523, −0.142) and 12 months postdischarge (SRM=0.73; 95% confidence interval=−2.318, −0.760).LimitationsFindings are limited to a modest-sized sample of individuals with mild-to-moderate balance impairment following stroke.ConclusionsThe CB&MStroke shows promise as a clinical scale for measuring change in walking balance in ambulatory community-dwelling adults poststroke. Future studies are recommended in a larger sample to validate and further refine the scale for use in this clinical population.
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Savino, Pierclaudio, Francesco Tondolo, Donato Sabia, Antonino Quattrone, Fabio Biondini, Gianpaolo Rosati, Mattia Anghileri, and Bernardino Chiaia. "Large-Scale Experimental Static Testing on 50-Year-Old Prestressed Concrete Bridge Girders." Applied Sciences 13, no. 2 (January 7, 2023): 834. http://dx.doi.org/10.3390/app13020834.
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The heritage of existing road infrastructures and in particular of bridges consists of structures that are approaching or exceeding their designed service life. Detrimental causes such as aging, fatigue and deterioration processes other than variation in loading conditions introduce uncertainties that make structural assessment a challenging task. Experimental data on their performances are crucial for a proper calibration of numerical models able to predict their behavior and life-cycle structural performance. In this scenario, an experimental research program was established with the aim of investigating a set of 50-year-old prestressed concrete bridge girders that were recovered from a decommissioned bridge. The activities included initial non-destructive tests, and then full-scale load tests followed by a destructive test on the material samples. This paper reports the experimental results of the full-scale tests conducted on the first group of four I-beams assumed to be in good condition from visual inspection at the time of testing. Loading tests were performed using a specifically designed steel reaction frame and a test setup equipment, as detailed in the present work. Due to the structural response of this first group of girders, a uniform behavior was found at both service and ultimate conditions. The failure mechanism was characterized by the crushing of the cast-in-situ top slab corresponding to a limited deflection, highlighting a non-ductile behavior. The outcomes of the experimental research are expected to provide new data for the life-cycle safety assessment of existing bridges through an extended database of validated experimental tests and models.
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Adiyoso, Wignyo. "Assessing Governments’ Emergency Responses to the COVID-19 Outbreak Using a Social Network Analysis (SNA)." SAGE Open 12, no. 2 (April 2022): 215824402110711. http://dx.doi.org/10.1177/21582440211071101.
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One of the effective ways of preventing the spread of the COVID-19 outbreak is dependent on non-pharmaceutical interventions due to the absence of a vaccine against the virus. This study aims to assess organizational emergency responses to COVID-19 using a social network analysis (SNA) method via Gephi. The data were obtained from a weekly Indonesian magazine, TEMPO, which reported on the Indonesian government’s response to COVID-19 from early March to early April 2020. One hundred and fifty actors represent the nodes and 180 connections denoted as edges are explored and analyzed using the SNA tool. The study found that the emergency response to the pandemic consisted of less solid, non-traditional structural interactions, and that the head of the task force played a lesser role in the response to this outbreak. The content analysis revealed that the team members’ issues of concern included coordination, hoaxes and fake issues, instruction/consultation, social distancing, and the lack of testing equipment. The results of the study are expected to contribute to the literature on research on emergency responses to pandemics. The findings also contribute to the development of the design of organizational emergency policies in the contexts of large-scale pandemics.
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Zhang, Qing Hua. "The Dynamic Response Analysis on Train Liquid Storage Tanks under Harmonic Excitation." Applied Mechanics and Materials 238 (November 2012): 248–51. http://dx.doi.org/10.4028/www.scientific.net/amm.238.248.
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This paper take the typical train liquid storage tank as research object, the fluid-solid coupling dynamic responses of the tank are analyzed under the track irregularities using finite element software ANSYS. The research indicates that the difference of the liquid volume in tank has great influence to the structural stress and strain. When the tank is not filled with liquid, the liquid has large-scale amplitude sloshing, and the stress and strain are much bigger than the static condition. But if the tank is full of the liquid, the stress and total amount of deformity of the tank can be obviously reduced.
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Lu, Shengzhuo, Wei Wang, Weidong Chen, Jingxin Ma, Yaqin Shi, and Chunlong Xu. "Behaviors of Thin-Walled Cylindrical Shell Storage Tank under Blast Impacts." Shock and Vibration 2019 (August 14, 2019): 1–21. http://dx.doi.org/10.1155/2019/6515462.
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Large steel storage tanks designed with long-span structures, employed for storing oil and fuel, have been widely used in many countries over the past twenty years. Most of these tanks are thin-walled cylindrical shells. Owing to the high risk of gas explosions and the resulting deaths, injuries, and economic losses, more thorough damage analyses of these large structures should be conducted. This study examines the structural response of a simplified steel storage tank under a blast impact, as calculated by the LS-DYNA software package. The numerical results are then compared with a scale-model experiment. On that basis, the simplified storage tank prototype, which has a 15 × 104 m3 capacity, is analyzed using numerical simulation. In this study, we address issues around the variation in structural responses—particularly of the failure mode, resultant displacement, structural energy, and dynamic strain under the impact. In addition, we also discuss the effects of varying the internal liquid level, constraint conditions, and blast intensity.
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Pantò, B., L. Macorini, and B. A. Izzuddin. "A two-level macroscale continuum description with embedded discontinuities for nonlinear analysis of brick/block masonry." Computational Mechanics 69, no. 3 (January 3, 2022): 865–90. http://dx.doi.org/10.1007/s00466-021-02118-x.
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AbstractA great proportion of the existing architectural heritage, including historical and monumental constructions, is made of brick/block masonry. This material shows a strong anisotropic behaviour resulting from the specific arrangement of units and mortar joints, which renders the accurate simulation of the masonry response a complex task. In general, mesoscale modelling approaches provide realistic predictions due to the explicit representation of the masonry bond characteristics. However, these detailed models are very computationally demanding and mostly unsuitable for practical assessment of large structures. Macroscale models are more efficient, but they require complex calibration procedures to evaluate model material parameters. This paper presents an advanced continuum macroscale model based on a two-scale nonlinear description for masonry material which requires only simple calibration at structural scale. A continuum strain field is considered at the macroscale level, while a 3D distribution of embedded internal layers allows for the anisotropic mesoscale features at the local level. A damage-plasticity constitutive model is employed to mechanically characterise each internal layer using different material properties along the two main directions on the plane of the masonry panel and along its thickness. The accuracy of the proposed macroscale model is assessed considering the response of structural walls previously tested under in-plane and out-of-plane loading and modelled using the more refined mesoscale strategy. The results achieved confirm the significant potential and the ability of the proposed macroscale description for brick/block masonry to provide accurate and efficient response predictions under different monotonic and cyclic loading conditions.
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Hansen, A. C. "A Method for Analyzing Wind Turbine Dynamic Response Test Data." Journal of Solar Energy Engineering 110, no. 4 (November 1, 1988): 335–39. http://dx.doi.org/10.1115/1.3268276.
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Correlation of wind turbine structural response with ambient wind conditions is an essential but expensive and difficult task. The numbers of variables involved in a typical atmospheric test, the poor correlation between measured instantaneous winds and the actual wind across a rotor disc, and the range of input and response time scales involved all make the correlation task formidable. This paper describes a method which has proven effective for analyzing test data and gaining insight into wind turbine behavior. The method basically consists of representing the dynamic response data in terms of its Fourier Series. A time-series of Fourier coefficients is then created to replace the original time-series raw data. The entire data set, consisting of thousands of rotor revolutions is subdivided into hundreds of sets, each consisting of the azimuth average of (typically) two to ten revolutions. One set of Fourier coefficients (magnitudes and phases of response) is calculated for each azimuth average. The resulting reduced data has a greatly compressed volume with virtually no loss of information. The result is greater insight and a manageable data set size. This new technique is demonstrated for two different wind turbines, an ESI-80 and a Hamilton Standard WTS-4.
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Roberts, Craig A., Mark J. Poppe, and Seth W. Chalmers. "Statistical Procedure Using an Expert Panel for Procurement of Emerging Transportation Technologies." Transportation Research Record: Journal of the Transportation Research Board 1840, no. 1 (January 2003): 1–9. http://dx.doi.org/10.3141/1840-01.
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State departments of transportation (DOTs) rely on established standards and open and competitive bidding to procure materials and technologies. This process hinders the implementation of new technologies until such standards are developed. A time lag occurs between the commercial introduction and implementation of new technologies, often delaying deployment of safety and cost improvement items by many years. One solution to this time lag is to prequalify products and technologies and use competitive bidding for procurement. The task is to develop a workable prequalification procedure that will satisfy acceptable standards of fairness. A procedure is proposed and is illustrated with a case study. The procedure uses an expert panel performing blind evaluations of prospective products and technologies. A longitudinal repeated measures design on two factors was developed. Pass-fail criteria were established. Evaluation test questions and a measurement scale were developed. Analysis-of-variance models were used for two rating response variables and a ranking response variable. Model assumptions were checked and departures were noted. The DOT involved in the study will use the procedure as a prototype for future testing of new technologies.
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Li, Honghao, Wei Zhao, and Wei Wang. "Dynamic Response of a 100,000 m3 Cylindrical Oil-Storage Tank under Seismic Excitations: Experimental Tests and Numerical Simulations." Shock and Vibration 2018 (September 10, 2018): 1–19. http://dx.doi.org/10.1155/2018/2074946.
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Considering the disastrous consequences of the oil tank failure, it is of great importance to ensure the safety of the large-scale oil tank under earthquakes. This study sheds light on investigating the dynamic response of a prototype 100,000 m3 cylindrical oil-storage tank under various seismic excitations. The foundation of the tank is also considered in this study so that the obtained results are closer to the reality. Shaking table tests are conducted using a 1/20 scale liquid-tank-foundation system under various seismic excitations. The test results reveal that the dynamic responses such as accelerations and the deformation of the test specimen in the major and minor vibration directions do not differ significantly. Finite element models are constructed for the test specimen and the prototype tank and are validated through comparing the simulation results with the test data. The simulation results suggest that it might be necessary to stiffen the locations on the tank wall where the thickness of the tank wall changes because the stresses at such locations may be close or even exceed the yield strength of the structural steel under severe earthquakes.
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Chen, Zengshun, Zhengang Xu, Yang Liu, Jun Fu, Huayan Cheng, Likai Zhang, and Xuanyi Xue. "Seismic Response of a Large LNG Storage Tank Based on a Shaking Table Test." Applied Sciences 12, no. 15 (July 29, 2022): 7663. http://dx.doi.org/10.3390/app12157663.
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In order to study the dynamic response of the LNG storage tank under the action of seismic load and the seismic isolation effect of the lead-core rubber bearing, this paper establishes the experimental storage tank model with reference to the structural form of the large-scale LNG storage tank, and the seismic response of the test tank is obtained using a shaking table test. Simplified mechanical models of non-isolated and isolated storage tanks are proposed and the seismic responses of the corresponding storage tanks are calculated using the Newmark-beta method. Under the action of seismic waves with different acceleration peaks, the results show that (a) more excitation directions of the seismic wave can lead to the greater acceleration and displacement response of the tank and (b) the isolation bearing has a damping effect on the acceleration response of the storage tank, but it has an amplifying effect on the displacement of the storage tank. Comparing the results of the simplified model and the shaking table test, it is found that the change trend of the acceleration response of the experimental results and simplified mechanical models is the same. The spectral characteristic curve of them is not large, which verifies the effectiveness of the simplified model.
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Azevedo, Nuno Monteiro, Fernando F. S. Pinho, Ildi Cismaşiu, and Murilo Souza. "Prediction of Rubble-Stone Masonry Walls Response under Axial Compression Using 2D Particle Modelling." Buildings 12, no. 8 (August 21, 2022): 1283. http://dx.doi.org/10.3390/buildings12081283.
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To predict the structural behaviour of ancient stone masonry walls is still a challenging task due to their strong heterogeneity. A rubble-stone masonry modeling methodology using a 2D particle model (2D-PM), based on the discrete element method is proposed given its ability to predict crack propagation by taking directly into account the material structure at the grain scale. Rubble-stone (ancient) masonry walls tested experimentally under uniaxial compression loading conditions are numerically evaluated. The stone masonry numerical models are generated from a close mapping process of the stone units and of the mortar surfaces. A calibration procedure for the stone-stone and mortar-mortar contacts based on experimental data is presented. The numerical studies show that the 2D-PM wall models can predict the formation and propagation of cracks, the initial stiffness and the maximum load obtained experimentally in traditional stone masonry walls. To reduce the simulation times, it is shown that the wall lateral numerical model adopting a coarser mortar discretization is a viable option for these walls. The mortar behaviour under compression with lateral confinement is identified as an important micro-parameter, that influences the peak strength and the ductility of rubble-masonry walls under uniaxial loading.
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Lala, Sayantani, Nandini Basumallick, Palas Biswas, and Somnath Bandyopadhyay. "Optimum Placement of Long Gauge FBG Sensor in Reinforced Concrete Bridge: A Case Study." Journal of Physics: Conference Series 2090, no. 1 (November 1, 2021): 012162. http://dx.doi.org/10.1088/1742-6596/2090/1/012162.
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Abstract In the world today, civil infrastructure plays a major role in the advancement of the modern age. They are huge in scale, complex in their behaviour and create great impact in everyday life. To ensure safety of these structures, assessment of their structural integrity is an important and challenging task. The sole purpose of structural health monitoring is to detect damage in the structures and suggest suitable rehabilitation measures. Various sensors are employed to achieve the task of damage detection and establish a warning system to avoid failure of the structures. For large structures, long-gauge Fibre Bragg Grating (FBG) sensors which are sensitive to the global behaviour, can be suitably used for this purpose. However, health monitoring of a structure with large number of sensors is expensive and hence there is a need to optimize the number of sensors deployed to minimize the cost of the exercise without compromising on performance assessment. For this purpose, several optimization algorithms are available in literature. In this study, the Effective Independence Method (EIM) which optimizes the response of the structure based on modal analysis, is used to derive the Optimum sensor placement (OSP) protocol for a reinforced concrete (RC) bridge-deck in Poland, the geometry of which has been taken from literature. This will enable the placement of 40 long gauge FBG sensors in regions for efficient damage response in the bridge-deck. Further, the optimum orientation of the sensors is further validated with a finite element model of the bridge-deck, where a moving load is applied, and strains are recorded in the sensing fibre in both longitudinal (along length) and transverse (along breadth) alignments. It has been found that long gauge FBG sensors placed in the transverse direction are more efficient in damage detection than when they are placed longitudinally.
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Francavilla, Antonella B., Massimo Latour, and Gianvittorio Rizzano. "The Design of a Real-Scale Steel Moment-Resisting Frame for Pseudo-Dynamic Earthquake Testing." Open Construction & Building Technology Journal 14, no. 1 (July 30, 2020): 174–84. http://dx.doi.org/10.2174/1874836802014010174.
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Background: Forthe reliable prediction of the non-linear response of structures, severe seismic events have proven to be a challenging task. Although much non-linear analysis software exists, the accuracy of the results depends on the assumptions made in the characterization of the members. Typically, the analytical models are calibrated using experimental observations. With this scope, experimental research remains the most reliable mean for the assessment of the seismic performance of structures, and it is crucial to target the development of new analytical models and design methods. Objective: Quasi-static tests can provide information on the non-linear behaviour of subassemblies, but it is often difficult to relate the imposed force or displacement histories to those that might occur during an earthquake. The pseudo-dynamic method combines an on-line computer simulation with experimental information about the tested structure, providing the application of realistic dynamic response histories. In this paper, the preliminary analysis and the design of a pseudo-dynamic testing facility for the experimental study of a real scale two storeys-two bays steel MRF, with classical and innovative joint details, are shown. Methods: Pushover and Incremental Dynamic Analyses carried out with Seismostruct software estimate the forces and displacements expected at each storey for the selected ground motions. These analyses have been performed by varying the structural detail of the beam-to-column connections. Results / Conclusion: In this paper, the analytical prediction of the performance of two bays-two storeys steel frames equipped with different solutions of beam-to-column joints is focused. Based on the performed analyses, it has been recognized that steel frames with partial strength joints can provide satisfactory performance under severe seismic actions provided that the joints are adequately designed.
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AlaviMerh, Javad, Jason Lavroff, Michael R. Davis, Damien S. Holloway, and Giles A. Thomas. "An Experimental Investigation of Ride Control Algorithms for High-Speed Catamarans Part 1: Reduction of Ship Motions." Journal of Ship Research 61, no. 01 (March 1, 2017): 35–49. http://dx.doi.org/10.5957/jsr.2017.61.1.35.
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Ride control systems are essential for comfort and operability of high-speed ships, but it remains an open question what is the optimum ride control method. To investigate the motions of a 112-m high-speed catamaran fitted with a ride control system, a 2.5-m model was tested in a towing tank. The model active control system comprised two transom stern tabs and a central T-Foil beneath the bow. Six ideal motion control feedback algorithms were used to activate the model scale ride control system and surfaces in a closed-loop control system: heave control, local motion control, and pitch control, each in a linear and nonlinear version. The responses were compared with the responses with inactive control surfaces and with no control surfaces fitted. The model was tested in head seas at different wave heights and frequencies and the heave and pitch response amplitude operators (RAOs), response phase operators, and acceleration response were measured. It was found that the passive ride control system reduced the peak heave and pitch motions only slightly. The heave and pitch motions were more strongly reduced by their respective control feedback. This was most evident with nonlinear pitch control, which reduced the maximum pitch RAO by around 50% and the vertical acceleration near the bow by about 40% in 60-mm waves (2.69 m at full scale). These reductions were influenced favorably by phase shifts in the model scale system, which effectively contributed both stiffness and damping in the control action.
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Sanchez, Wilson D., Jose V. de Brito, and Suzana M. Avila. "Structural Health Monitoring Using Synchrosqueezed Wavelet Transform on IASC-ASCE Benchmark Phase I." International Journal of Structural Stability and Dynamics 20, no. 12 (September 24, 2020): 2050138. http://dx.doi.org/10.1142/s0219455420501382.
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Civil structures suffer deterioration either for years of service, deficiency due to environmental factors or damages caused by factors such as earthquakes, winds, impact loads, and cyclical loads. When a structure ages, it is necessary to know its state of health and make a decision of maintenance or replacement. When a structure such as a bridge or building is subjected to destructive environmental forces, determining its state of health becomes a priority since its recovery is urgently required to function normally. Structural Health Monitoring (SHM) is a technology that aims to prevent the collapse of structures and loss of human life through early diagnosis of the health status of a structure. There are a large number of damage detection methods that can be classified into (1) non-destructive testing methods, (2) dynamic characteristics-based damage detection methods, (3) dynamic response-based, (4) multi-scale damage detection method and (5) damage detection methods with consideration of uncertainties. In this work, it is implemented synchrosqueezed wavelet transform (SWT), which can be classified as a methods based on the dynamic response. To validate the robustness of the method it is identified first, the natural frequencies of the Benchmark Phase I without damage, which consists of a steel structure of 4-story [Formula: see text] bay 3D steel frame structure subjected to ambient vibrations. Subsequently, some damage patterns are validated according to IASC-ASCE SHM Task Group. The results obtained in the identification of natural frequencies are compared with those reported in literature. SWT was efficient, presenting a minimum error of 0.12[Formula: see text] and a maximum of 3.06[Formula: see text] in the identification of natural frequencies about the AISCE-ASCE group model. SWT overcomes some other damage detection methods, which are deficient in the identification of closely spaced frequencies, commonly present in many civil structures due to symmetric geometry or similar physical properties in different directions.
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Mo, Zonglai, Kefeng Xie, Fengcheng Zhao, Jun Li, and Yanjun Li. "A Small Floating Platform Designed for Unmanned Defense System." Journal of Marine Science and Engineering 11, no. 2 (January 26, 2023): 278. http://dx.doi.org/10.3390/jmse11020278.
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A small floating platform designed for an unmanned short-range defense system is proposed. The structures of the proposed floating platform and weapon system are detailed and described. The floating platform is investigated via virtual prototype technology in the aspects of the platform motion under sea waves of up to Beaufort wind and Douglas sea (wind-sea) scale 5. The motion equations of the floating platform are established according to the ship motion theory, and the movement of the floating platform under different wind-sea scales are simulated and analysed via multi-body fluid dynamics analysis software. To decide the proper size of the platform, the dynamic response of the floating platforms with different sizes is analysed and evaluated under various sea conditions based on multi-body dynamics. A scaled model experiment was conducted and compared with simulation results to verify the theoretical model. A verification experiment was also conducted in a water tank for the performance of the platform via simulated wave disturbance. Results show that the designed floating platform could provide a stable platform in the horizontal direction under a wind-sea scale 3 environment for the defense weapon system, which well meets the design requirement.
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Wang, Ting, Chien-Liang Lin, and Yu-Sheng Su. "Continuance Intention of University Students and Online Learning during the COVID-19 Pandemic: A Modified Expectation Confirmation Model Perspective." Sustainability 13, no. 8 (April 20, 2021): 4586. http://dx.doi.org/10.3390/su13084586.
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The prevalence of COVID-19 has changed traditional teaching modes. For many teachers, online learning effectively compensated for the absence of traditional face-to-face instruction. Online learning can support students and schools and can create unique opportunities under emergency management. Educational institutions in various countries have launched large-scale online course modes in response to the pandemic. Additionally, online learning during a pandemic differs from traditional online learning modes. Through surveying students in higher education institutions, educational reform under emergency management can be explored. Therefore, university students were surveyed to investigate their continuance intention regarding online learning during the pandemic. Expectation confirmation theory was extended using the task-technology fit model to ascertain whether the technical support of promoting online learning helped student’s complete course learning tasks during the pandemic and spawned a continuance intention to use online learning in the future. Data were collected through online questionnaires. A total of 854 valid responses were collected, and partial least squares structural equation modeling was employed to verify the research hypotheses. The results revealed that the overall research framework largely explained continuance intention. Concrete suggestions are proposed for higher education institutions to promote online learning modes and methods after the COVID-19 pandemic.
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Puengpipattrakul, Walaipun. "Modeling the determinants of English writing performance: Directions to interdisciplinary writing instruction." Electronic Journal of Foreign Language Teaching 18, no. 2 (2021): 140–55. http://dx.doi.org/10.56040/wpmd1822.
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This cross-sectional study examines the impact of five learner-factor groups – intellectual, learning, social, environmental, and mental domains, on writing performance using confirmatory factor analysis and multiplegroup structural equation modeling, and qualitative analysis of response scripts. Triangulated data was collected from the persuasive-writing task scores and the Likert-scale and interview-based questionnaire responses of 499 first-year Thai undergraduates from 11 faculties at a university in central Thailand. The results showed the global fits between the hypothesized model and the empirical data (Chi-Square = 330, df = 169, p-value < .001, CFI = 0.96, TLI = 0.95, RMSEA = 0.04). The intellectual appeared to be the most powerful factor affecting participant writing performance. The learning factors which impacted the writing performance of the Science and Technology group (β = -.24, t = -2.60) with the highest degree of significance was out-of-class activity (β = .81, t = 42.12, p ≤ .05). Intellectual factors were shown to affect female student writing performance (β = .62, t = 9.42) more so than males (β = .44, t = 6.14, p ≤ .05). Participants viewed instrumental motivation as affecting their writing performance (mean = 2.98, SD = .93, p = .04). Qualitative data from gender non-conforming participants’ responses also uncovered underlying factors: remote student-teacher relationships and unwillingness to communicate, impairing their English learning and writing performance. Insights gleaned from the responses of gender non-conforming participants have led to suggestions for further research regarding writing instruction.
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Azuma, Miu, Osamu Nomura, Takanari Sakuma, and Yuki Soma. "Complex motivations of Japanese medical students to an online medical English course during the COVID-19 pandemic." MedEdPublish 12 (April 6, 2022): 25. http://dx.doi.org/10.12688/mep.19042.1.
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Background: In response to globalism, many East-Asian countries now include a Medical English course in their undergraduate medical education syllabus. The purpose of this study was to explore the relationship between the related attribute factors of students' motivation to learn medical English through an online modality. Methods: Of 134 eligible fourth-year medical students who participated in an Online Medical English course at a Japanese medical school, 105 were enrolled in this single cohort study. The participants completed pre- and post-course surveys regarding their motivation during the course, including perceived academic control and task value, and their assignment scores. A structural equation model was used to examine the hypothesized relationship of constructs, based on control-value theory. Results: The model showed a good fit for the data (χ2[df=7] = 1.821, p=0.969, CFI = 1.000, RMSEA < 0.001, SRMR < 0.05, GFI = 0.993, AGFI = 0.980). The latent variables of the perceived course achievement related to the observed variables of academic control and task value scale scores, and negatively predicted willingness for self-study after course completion. In addition, the preference of English as the course language negatively predicted willingness for self-study of medical English. Conclusion: Choice of English as the language of instruction and perceived high course achievement negatively predicted students’ motivation for further English self-study after the class. The importance of incorporating the perspective of lifelong learning into the teaching of medical English was recognized.
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Ma, Leixin, Ke Hu, Shixiao Fu, Torgeir Moan, and Runpei Li. "A Hybrid Empirical-Numerical Method for Hydroelastic Analysis of a Floater-and-Net System." Journal of Ship Research 60, no. 01 (March 1, 2016): 14–29. http://dx.doi.org/10.5957/jsr.2016.60.1.14.
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Because of scale effects and inappropriate hydrodynamic models, the nonlinear hydroelastic response of net cages used for fish-farming cannot be analyzed precisely with traditional model testing or combinations of finite element methods (FEMs) and load models. In this study, an innovative hybrid method is proposed to determine the hydroelastic response of full-scale floater-and-net systems more accurately. In this method, the net for the fish cage was vertically and peripherally divided into similar interconnected sections with different hydrodynamic parameters, which were assumed to be uniformly distributed over each section. A model of a typical section was subjected to various towing velocities, oscillation periods, and amplitudes in a towing tank to simulate the potential motions of all sections in the net under various currents, waves, and floater movements. By analyzing the measured hydrodynamic force from this test section, a hydrodynamic force database for a typical net section under various currents, waves, and floater motions was built. Finally, based on an FEM, the modified Morison equation and the hydrodynamic force database, the hydroelastic behavior of the full-scale fish cage was calculated with an iterative scheme. It is demonstrated that this hybrid method is able to produce correct hydroelastic response for both steady and oscillatory flows. The hydroelastic response of a two-dimensional example of a full-length net panel with steady currents and floater oscillations was studied in detail.
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He, Tao, Dakui Feng, Liwei Liu, Xianzhou Wang, and Hua Jiang. "CFD Simulation and Experimental Study on Coupled Motion Response of Ship with Tank in Beam Waves." Journal of Marine Science and Engineering 10, no. 1 (January 14, 2022): 113. http://dx.doi.org/10.3390/jmse10010113.
Full textAbstract:
Tank sloshing is widely present in many engineering fields, especially in the field of marine. Due to the trend of large-scale liquid cargo ships, it is of great significance to study the coupled motion response of ships with tanks in beam waves. In this study, the CFD (Computational Fluid Dynamics) method and experiments are used to study the response of a ship with/without a tank in beam waves. All the computations are performed by an in-house CFD solver, which is used to solve RANS (Reynold Average Navier-Stokes) equations coupled with six degrees-of-freedom solid-body motion equations. The Level Set Method is used to solve the free surface. Verification work on the grid number and time step size has been conducted. The simulation results agree with the experimental results well, which shows that the numerical method is accurate enough. In this paper, several different working conditions are set up, and the effects of the liquid height in the tank, the size of the tank and the wavelength ratio of the incident wave on the ship’s motion are studied. The results show the effect of tank sloshing on the ship’s motion in different working conditions.
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Chavanne, Alice V., Charlotte Meinke, Till Langhammer, Kati Roesmann, Joscha Boehnlein, Bettina Gathmann, Martin J. Herrmann, et al. "Individual-Level Prediction of Exposure Therapy Outcome Using Structural and Functional MRI Data in Spider Phobia: A Machine-Learning Study." Depression and Anxiety 2023 (August 22, 2023): 1–11. http://dx.doi.org/10.1155/2023/8594273.
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Machine-learning prediction studies have shown potential to inform treatment stratification, but recent efforts to predict psychotherapy outcomes with clinical routine data have only resulted in moderate prediction accuracies. Neuroimaging data showed promise to predict treatment outcome, but previous prediction attempts have been exploratory and reported small clinical sample sizes. Herein, we aimed to examine the incremental predictive value of neuroimaging data in contrast to clinical and demographic data alone (for which results were previously published), using a two-level multimodal ensemble machine-learning strategy. We used pretreatment structural and task-based fMRI data to predict virtual reality exposure therapy outcome in a bicentric sample of N = 190 patients with spider phobia. First, eight 1st-level random forest classifications were conducted using separate data modalities (clinical questionnaire scores and sociodemographic data, cortical thickness and gray matter volumes, functional activation, connectivity, connectivity-derived graph metrics, and BOLD signal variance). Then, the resulting predictions were used to train a 2nd-level classifier that produced a final prediction. No 1st-level or 2nd-level classifier performed above chance level except BOLD signal variance, which showed potential as a contributor to higher-level prediction from multiple regions across the brain (1st-level balanced accuracy = 0.63 ). Overall, neuroimaging data did not provide any incremental accuracy for treatment outcome prediction in patients with spider phobia with respect to clinical and sociodemographic data alone. Thus, we advise caution in the interpretation of prediction performances from small-scale, single-site patient samples. Larger multimodal datasets are needed to further investigate individual-level neuroimaging predictors of therapy response in anxiety disorders.
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Sagala, Gaffar Hafiz, Ramdhansyah Ramdhansyah, and Ulfa Nurhayani. "Learning Community and Its Impact on Attitude toward Computer-Based Statistics." Dinamika Pendidikan 16, no. 1 (June 30, 2021): 44–53. http://dx.doi.org/10.15294/dp.v16i1.27303.
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This study examined the three dimensions that should exist in a learning community, namely Student Cohesiveness, Integration, and Task Orientation, related to their influence on attitude toward computer-based statistics. Attitude toward computer-based statistics itself is measured using constructs of the revised Technology Acceptance Model (TAM). This study was designed to justify the value of information systems (IS) in overcoming accounting students' statistical problems. The use of IS probable to reduce the pressure in dealing with statistics so that there is an opportunity to increase accounting students' competitive advantage. The respondents consisted of 105 undergraduate accounting students. The data was collected using a 5-scale Likert questionnaire then analyzed using Structural Equational Modelling (SEM). With purposive sampling, this study was collected 105 responses obtained from private and state universities. The results indicate that task orientation is the key indicator of the learning community, affecting attitude toward computer-based statistics. Meanwhile, the second-order factors show that all three predictors were essential in explaining attitude toward computer-based statistics and significantly impacted Reuse Intention. This study also suggests implementing an informal learning community to build learning dynamics that are more independent but still controllable so that the learning topic is integrated with certain subjects.
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Fu, Qiang. "Experimental Analysis on Dynamic Response of X-Section Piled Raft Composite Foundation under Cyclic Axial Load for Ballastless Track in Soft Soil." Shock and Vibration 2021 (October 19, 2021): 1–17. http://dx.doi.org/10.1155/2021/4561806.
Full textAbstract:
Large-scale model tests were established at a scale of 1/5 using a 7 m deep model tank with cross-sectional dimension of 5 m × 4 m, to study the vibration response characteristics of ballastless track, embankment, and X-section piled raft foundation under cyclic axial load, including the vibration displacement, velocity, dynamic soil, and pile stress. Cyclic dynamic loading can be achieved by controlling the loading frequency and cycles through the vibration servo control loading system. The test results are presented in the variation of dynamic displacement, velocity, and stress of X-section piled raft composite foundation. The vibration displacement, velocity, and stress of the track, embankment, and pile foundation follow a pattern of vibration characteristics of loading sine wave. The vibration characteristics of loading waves can be identified easily from the peaks and troughs in the dynamic response of displacement, velocity, and stress at many locations of track slab, embankment, cushion, and underlying soil, at which the vibration response presents almost monotonically increasing tendency with the loading frequencies. With the increase of loading frequency, the vibration responses at the track structure and embankment have higher increasing rates than those at substructure (raft, cushion, and subsoil). The piled raft bears more dynamic load than cushion and subsoils, to ensure long-term dynamic stability and safety of the foundation soils. The model testing results provide a better understanding of the dynamic response characteristics of ballastless track, embankment, and X-section piled raft foundation under cyclic axial load in soft soil.
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Azuma, Miu, Osamu Nomura, Takaya Sakuma, and Yuki Soma. "Complex motivations of Japanese medical students to an online medical English course during the COVID-19 pandemic." MedEdPublish 12 (March 20, 2023): 25. http://dx.doi.org/10.12688/mep.19042.2.
Full textAbstract:
Background: In response to globalism, many East-Asian countries now include a Medical English course in their undergraduate medical education syllabus. Traditional didactic educational culture is a potential barrier for teaching and learning medical English in East-Asian countries. Online technology-based learning has been recognized as an effective instructional strategy for teaching medical English in the East. The purpose of this study was to explore the relationship between the related attribute factors of students' motivation to learn medical English through an online modality. Methods: Of 134 eligible fourth-year medical students who participated in an online medical English course at a Japanese medical school, 105 were enrolled in this single cohort study. The participants completed pre- and post-course surveys regarding their motivation during the course, including perceived academic control and task value, and their assignment scores. A structural equation model was used to examine the hypothesized relationship of constructs, based on control-value theory. Results: The model showed a good fit for the data (χ 2[df=7] = 1.821, p=0.969, CFI = 1.000, RMSEA < 0.001, SRMR < 0.05, GFI = 0.993, AGFI = 0.980). The latent variables of the perceived course achievement related to the observed variables of academic control and task value scale scores, and negatively predicted willingness for self-study after course completion. In addition, the preference of English as the course language negatively predicted willingness for self-study of medical English. Conclusion: Choice of English as the language of instruction and perceived high course achievement negatively predicted students’ motivation for further English self-study after the class. The importance of incorporating the perspective of lifelong learning into the teaching of medical English was recognized.
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Naeim, Farzad, Arzhang Alimoradi, and Shahram Pezeshk. "Selection and Scaling of Ground Motion Time Histories for Structural Design Using Genetic Algorithms." Earthquake Spectra 20, no. 2 (May 2004): 413–26. http://dx.doi.org/10.1193/1.1719028.
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This paper presents a new approach to selection of a set of recorded earthquake ground motions that in combination match a given site-specific design spectrum with minimum alteration. The scaling factors applied to selected ground motions are scalar values within the range specified by the user. As a result, the phase and shape of the response spectra of earthquake ground motions are not tampered with. Contrary to the prevailing scaling methods where a preset number of earthquake records (usually between a single component to seven pairs) are selected first and scaled to match the design spectrum next, the proposed method is capable of searching a set consisting of thousands of earthquake records and recommending a desired subset of records that match the target design spectrum. This task is achieved by using a genetic algorithm (GA), which treats the union of 7 records and corresponding scaling factors as a single “individual.” The first generation of individuals may include a population of, for example, 200 records. Then, through processes that mimic mating, natural selection, and mutation, new generations of individuals are produced and the process continues until an optimum individual (seven pairs and scaling factors) is obtained. The procedure is fast and reliable and results in records that match the target spectrum with minimal tampering and the least mean square of deviation from the target spectrum.
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Lin, Yi-Hsin, Qihui Chen, Pin-Chao Liao, Po-Han Chen, and Shuping Cheng. "The Moderating Effect of Guanxi on the Dynamic Capacity and Competitive Advantage of Chinese International Contractors." Advances in Civil Engineering 2018 (August 1, 2018): 1–17. http://dx.doi.org/10.1155/2018/3638152.
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With the active support of the national policy “One Belt and One Road” Initiative, Chinese contractors seized this historic opportunity to accelerate strategic globalization, and they gradually stood out in international construction projects owing to their low-cost advantage. However, despite China having large-scale contractors and wide-range business, compared to developed countries, a considerably large gap still exists. China is confronted with complex and changeable international projects filled with increasing competition. Thus, it is both a focus issue and a major task for Chinese international contractors, and many scholars, to consider how Chinese contractors can obtain and maintain long-term competitive advantages to improve their capabilities in response to dynamic environmental changes. Therefore, the objectives of this study are (1) to study the influence of the dynamic capability of Chinese contractors on competitive advantage in a project and (2) to explore the moderating effect of Chinese guanxi on the dynamic capability and competitive advantage of Chinese international contractors. This study primarily aimed at researching the impact of dynamic capacity of Chinese contractors on competitive advantage and the moderating effects of Chinese guanxi. The findings suggest that the environmental perception capability and the integration and coordination capability of the dynamic capability have a significant positive effect on the project competitive advantage; business guanxi positively moderates the relationship between the environmental perception capability and the competitive advantage. Business guanxi also negatively moderates the relationship between learning ability and competitive advantage, while political guanxi negatively moderates the relationship between the environmental perception capability and competitive advantage. This paper contributes to the construction management literature not only by providing empirical evidence on the dynamic capability and competitive advantage of Chinese contractors but also by expanding guanxi research. The results may also help Chinese contractors by providing strategic reform guidance and sustainable development in international construction projects.
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Huang, Haohang, Jiayi Luo, Erol Tutumluer, John M. Hart, and Andrew J. Stolba. "Automated Segmentation and Morphological Analyses of Stockpile Aggregate Images using Deep Convolutional Neural Networks." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 10 (August 27, 2020): 285–98. http://dx.doi.org/10.1177/0361198120943887.
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Particle size and morphological/shape properties ensure the reliable and sustainable use of all aggregate skeleton materials placed as constructed layers in transportation applications. The composition and packing of these aggregate assemblies rely heavily on particle size and morphological properties, which affect layer strength, modulus, and deformation response under vehicular loading and therefore facilitate the quality assurance/quality control (QA/QC) process. Aggregate imaging systems developed to date for size and shape characterization, however, have primarily focused on measurement of separated or slightly contacting aggregate particles. Development of efficient computer vision algorithms is urgently needed for image-based evaluations of densely stacked (or stockpile) aggregates, which requires image segmentation of a stockpile for the size and morphological properties of individual particles. This paper presents an innovative approach for automated segmentation and morphological analyses of stockpile aggregate images based on deep learning techniques. A task-specific stockpile aggregate image dataset is established from images collected from various quarries in Illinois. Individual particles from the stockpile images are manually labeled on each image associated with particle locations and regions. A state-of-the-art object detection and segmentation framework called Mask R-CNN is then used to train the image segmentation kernel, which enables user-independent segmentation of stockpile aggregate images. The segmentation results show good agreement with ground-truth labeling and improve the efficiency of size and morphological analyses conducted on densely stacked and overlapping particle images. Based on the presented approach, stockpile aggregate image analysis promises to become an efficient and innovative application for field-scale and in-place evaluations of aggregate materials.
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Borich, Michael R., Steven L. Wolf, Andrew Q. Tan, and Jacqueline A. Palmer. "Targeted Neuromodulation of Abnormal Interhemispheric Connectivity to Promote Neural Plasticity and Recovery of Arm Function after Stroke: A Randomized Crossover Clinical Trial Study Protocol." Neural Plasticity 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/9875326.
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Background. Despite intensive rehabilitation efforts, most stroke survivors have persistent functional disability of the paretic arm and hand. These motor impairments may be due in part to maladaptive changes in structural and functional connections between brain regions. The following early stage clinical trial study protocol describes a noninvasive brain stimulation approach to target transcallosally mediated interhemispheric connections between the ipsi- and contralesional motor cortices (iM1 and cM1) using corticocortical paired associative stimulation (ihPAS). This clinical trial aims to characterize ihPAS-induced modulation of interhemispheric connectivity and the effect on motor skill performance and learning in chronic stroke survivors. Methods/Design. A repeated-measures, cross-over design study will recruit 20 individuals post-stroke with chronic mild–moderate paretic arm impairment. Each participant will complete an active ihPAS and control ihPAS session. Assessments of cortical excitability and motor skill performance will be conducted prior to and at four time points following the ihPAS intervention. The primary outcome measures will be: TMS-evoked interhemispheric motor connectivity, corticomotor excitability, and response time on a modified serial reaction time task. Discussion/Conclusion. The findings from this single-site early stage clinical trial will provide foundational results to inform the design of larger-scale, multisite clinical trials to evaluate the therapeutic potential of ihPAS-based neuromodulation for upper limb recovery after stroke. This trial is registered with NCT02465034.
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Irvine, Martin. "Pitch and Heave Tests and Uncertainty Assessment for a Surface Combatant in Regular Head Waves." Journal of Ship Research 52, no. 02 (June 1, 2008): 146–63. http://dx.doi.org/10.5957/jsr.2008.52.2.146.
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Towing-tank experiments of coupled pitch and heave motions are presented for a surface combatant advancing in regular head waves. The data include ballasting parameters, time histories, fast Fourier transform (FFT), Fourier series amplitudes, and pitch and heave transfer functions and phases for a range of speeds, wave steepnesses, and wave frequencies. The geometry is David Taylor Model Basin (DTMB) model 5512, which is a 1/46.6 scale geosim of DTMB model 5415 (DDG-51) with Lpp = 3.048 m. The experiments are performed in a 3.048 × 3.048 × 100 m towing tank equipped with a plunger-type wave maker. The test program is undertaken to provide a validation data set for unsteady Reynolds-averaged Navier-Stokes and other computational fluid dynamics (CFD) codes, including rigorous uncertainty assessment of the experimental results following standard procedures. Results indicate that the regular head waves are linear with second- and third-order magnitudes consistent with third-order Stokes waves. Pitch and heave responses and phases show expected trends for long and short wavelengths and are linear or Ak independent for all test conditions. Maximum response occurs for frequency of encounter equal to pitch and heave natural frequencies and Lpp / λ = 0.75. Under these conditions, an equation is derived that predicts the Froude number for maximum response as a function of ship geometrical coefficients.
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Reeck, Crystal, O’Dhaniel A. Mullette-Gillman, R. Edward McLaurin, and Scott A. Huettel. "Beyond money: Risk preferences across both economic and non-economic contexts predict financial decisions." PLOS ONE 17, no. 12 (December 16, 2022): e0279125. http://dx.doi.org/10.1371/journal.pone.0279125.
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Important decisions about risk occur in wide-ranging contexts, from investing to healthcare. While an underlying, domain-general risk attitude has been identified across contexts, it remains unclear what role it plays in shaping behavior relative to more domain-specific risk attitudes. Clarifying the relationship between domain-general and domain-specific risk attitudes would inform decision-making theories and the construction of decision aids. The present research assessed the relative contribution of domain-general and domain-specific risk attitudes to financial risk taking. We examined risk attitudes across different decision domains, as revealed through a well-validated measure, the Domain-Specific Risk-Taking Scale (DOSPERT). Confirmatory factor analysis indicated that a domain-general risk attitude shaped responses across multiple domains, and structural equation modeling showed that this domain-general risk attitude predicted observed behavioral risk premiums in a financial decision-making task better than domain-specific financial risk attitudes. Thus, assessments of risk attitudes that include both economic and non-economic domains improve predictions of financial risk taking due to the enhanced insight they provide into underlying, domain-general risk preferences.
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Wang, Tongyue, Rongdi Shao, and Luoxi Hao. "Effects of Different Nocturnal Lighting Stimuli on Melatonin, Sleep and Cognitive Performance of Workers in Confined Spaces." Buildings 13, no. 8 (August 21, 2023): 2112. http://dx.doi.org/10.3390/buildings13082112.
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Exposure to light during overtime work at night in confined spaces may disrupt the normal circadian clock, affect hormone secretion, sleep quality and performance, thereby posing great risks to the physical and mental health of night workers. Integrative lighting should be adopted to reduce the disturbance of normal physiological rhythm, while meeting the visual requirements of work. Through adjustable LED (CCT 6000 K/2700 K) and different vertical illuminance, five lighting patterns with different circadian stimuli (CS = 0.60, 0.30. 0.20, 0.10 and 0.05) were conducted, respectively, in a sleep lab using a within-subject design. Each lighting pattern lasted for 5 h every night. Eight healthy adults were recruited to complete the night work and their salivary melatonin, Karolinska sleepiness scale (KSS), Psychomotor Vigilance Task (PVT) and sleep quality were tested. The results showed that subjective sleepiness and melatonin concentration increased rapidly under low intervention (CS = 0.05) with the best sleep quality, while they decreased in high intervention (CS = 0.60) at night and led to significantly higher levels of sleepiness the next morning (p < 0.05). For the PVT, the middle intervention (CS = 0.30) showed the lowest response time and least errors (p < 0.05), suggesting that appropriate illuminance can improve visual performance. To reduce biorhythm disruptions, lower lighting stimulation is preferred during night work. For difficult visual tasks, high illuminances may not improve visual performance; just a slight increase in the existing lighting levels is adequate. Lighting interventions have a clear impact on sleep improvement and work capacity for those working overtime, and they may be translatable to other shift work scenarios.
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Tsipianitis, Alexandros, and Yiannis Tsompanakis. "Seismic Vulnerability Assessment of Liquid Storage Tanks Isolated by Sliding-Based Systems." Advances in Civil Engineering 2018 (October 3, 2018): 1–14. http://dx.doi.org/10.1155/2018/5304245.
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Liquid-filled tanks are effective storage infrastructure for water, oil, and liquefied natural gas (LNG). Many such large-scale tanks are located in regions with high seismicity. Therefore, very frequently base isolation technology has to be adopted to reduce the dynamic distress of storage tanks, preventing the structure from typical modes of failure, such as elephant-foot buckling, diamond-shaped buckling, and roof damage caused by liquid sloshing. The cost-effective seismic design of base-isolated liquid storage tanks can be achieved by adopting performance-based design (PBD) principles. In this work, the focus is given on sliding-based systems, namely, single friction pendulum bearings (SFPBs), triple friction pendulum bearings (TFPBs), and mainly on the recently developed quintuple friction pendulum bearings (QFPBs). More specifically, the study is focused on the fragility analysis of tanks isolated by sliding-bearings, emphasizing on isolators’ displacements due to near-fault earthquakes. In addition, a surrogate model has been developed for simulating the dynamic response of the superstructure (tank and liquid content) to achieve an optimal balance between computational efficiency and accuracy.
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Reid, Denise. "A Neo-Piagetian Analysis of Infants' Visual-Motor Abilities." Occupational Therapy Journal of Research 9, no. 5 (September 1989): 287–304. http://dx.doi.org/10.1177/153944928900900503.
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Visual-motor abilities in infants were investigated within a neo-Piagetian framework of development. Case's (1985) theory of intellectual development provided the conceptual base for this study. The study's objective was to establish whether development in the motor domain proceeds in a stagelike fashion. This aim was addressed by (a) the development of a model that suggested how the structural changes, as specified by Case's theory, might manifest themselves in the subdomain of the use of an object to execute a simple motor response and (b) the measurement of infants' performances on a set of newly constructed tasks designed to assess the sequence of changes in cognitive operations. Forty children, aged 4 to 18 months, were tested. Subjects were classified by age into one of four groups corresponding to the substages of the sensorimotor stage postulated by the theory. The general hypothesis that children's visual-motor abilities would proceed through four substages was supported. The individual pattern of performance across substages yielded a perfect Guttman scale (Guttman, 1950). Analysis of variance indicated no significant deviation from linearity for any group, no sex effects, and no Sex × Age interactions, as predicted. This study suggests that a cognitive developmental approach can provide a more complete understanding of visual-motor abilities in children, because it can explain recurrent cycles in development and, given an appropriate task analysis, predict the skill level of a child at a given age. The implications for future research are also discussed.
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Kim, Minyoung. "A Pilot Study on the Use of App Tools in Synchronous Video Korean Lectures." Korean Association For Learner-Centered Curriculum And Instruction 22, no. 14 (July 31, 2022): 1–17. http://dx.doi.org/10.22251/jlcci.2022.22.14.1.
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Objectives The purpose of this study is to design a teaching method in which a Korean grammar app is applied to “Synchronous Classroom Access Type” video lectures. Synchronous video classes are generally used, but there are many problems as we know. So I chose a method of Blended Learning as a complement to it. However, since the experiment has to be done on a large scale, a pilot study was first conducted in this study.
Methods This paper designed a teaching method that applied “Sejong Korean Grammar APP” while taking Skype Business platform classes. For this, First I analyzed the classroom environment. Second I made a hypothesis after exploring theories. Third the experiment was designed and conducted. The control group submit the Handout task, and the experimental group played the APP game. All students took midterm and final exams and were interviewed.
Results The purposes of this study were to specify variables related to convergence competency, and to analyze the structural relationships among them. The purposes of this study were to specify variables related to convergence competency, and to analyze the structural relationships among them.
Conclusions As a result, the experimental group achieved good results. There were also positive responses from individual interviews. This pilot study suggests that video education and app-using classes can be harmonized. However, this study needs to be modified in many parts because the sample of the experimental group is small.
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Ponzo, Felice C., Antonio D. Cesare, Gianmarco Leccese, and Domenico Nigro. "Shaking table tests of a base isolated structure with Double Concave Friction Pendulum bearings." Bulletin of the New Zealand Society for Earthquake Engineering 48, no. 2 (June 30, 2015): 136–44. http://dx.doi.org/10.5459/bnzsee.48.2.136-144.
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An extensive experimental testing programme named JETBIS project (Joint Experimental Testing of Base Isolation Systems) was developed within the RELUIS II project (Task 2.3.2) and RELUIS III project (Line 6) involving partners from different Italian universities. This paper describes the seismic tests performed by the research unit of University of Basilicata (UNIBAS) on an isolation system based on Double Concave Friction Pendulum (DCFP) bearings. The DCFP bearing contains two separate concave sliding surfaces and exhibits different hysteretic properties at different stages of displacement response. The main objective of this work is to evaluate the horizontal response of the DCFP isolators by means of controlled-displacement tests and shaking table tests. The experimental model was a 1/3 scaled steel framed structure with one storey and one bay in both directions. Four DCFP bearings with equal properties of the sliding surfaces were considered. In this work, three different sliding surface conditions (with and without lubrication) have been studied. The isolated base model was subjected to 8 natural earthquakes of increasing seismic intensities and considering two mass configurations (with both symmetrical and eccentric masses). The reliability of the design procedure considered for the isolation system was verified also when relevant residual displacements occurred due to previous earthquakes. In this paper, the comparisons between the experimental outcomes and the numerical results of nonlinear time-history analyses using SAP2000 are shown.
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Raveh, Barak, Liping Sun, Kate L. White, Tanmoy Sanyal, Jeremy Tempkin, Dongqing Zheng, Kala Bharath, et al. "Bayesian metamodeling of complex biological systems across varying representations." Proceedings of the National Academy of Sciences 118, no. 35 (August 27, 2021): e2104559118. http://dx.doi.org/10.1073/pnas.2104559118.
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Comprehensive modeling of a whole cell requires an integration of vast amounts of information on various aspects of the cell and its parts. To divide and conquer this task, we introduce Bayesian metamodeling, a general approach to modeling complex systems by integrating a collection of heterogeneous input models. Each input model can in principle be based on any type of data and can describe a different aspect of the modeled system using any mathematical representation, scale, and level of granularity. These input models are 1) converted to a standardized statistical representation relying on probabilistic graphical models, 2) coupled by modeling their mutual relations with the physical world, and 3) finally harmonized with respect to each other. To illustrate Bayesian metamodeling, we provide a proof-of-principle metamodel of glucose-stimulated insulin secretion by human pancreatic β-cells. The input models include a coarse-grained spatiotemporal simulation of insulin vesicle trafficking, docking, and exocytosis; a molecular network model of glucose-stimulated insulin secretion signaling; a network model of insulin metabolism; a structural model of glucagon-like peptide-1 receptor activation; a linear model of a pancreatic cell population; and ordinary differential equations for systemic postprandial insulin response. Metamodeling benefits from decentralized computing, while often producing a more accurate, precise, and complete model that contextualizes input models as well as resolves conflicting information. We anticipate Bayesian metamodeling will facilitate collaborative science by providing a framework for sharing expertise, resources, data, and models, as exemplified by the Pancreatic β-Cell Consortium.
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Cauvy-Fraunié, S., T. Condom, A. Rabatel, M. Villacis, D. Jacobsen, and O. Dangles. "Technical Note: Glacial influence in tropical mountain hydrosystems evidenced by the diurnal cycle in water levels." Hydrology and Earth System Sciences 17, no. 12 (December 4, 2013): 4803–16. http://dx.doi.org/10.5194/hess-17-4803-2013.
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Abstract. Worldwide, the rapid shrinking of glaciers in response to ongoing climate change is modifying the glacial meltwater contribution to hydrosystems in glacierized catchments. Determining the influence of glacial runoff to streams is therefore of critical importance to evaluate potential impact of glacier retreat on water quality and aquatic biota. This task has challenged both glacier hydrologists and ecologists over the last 20 yr due to both structural and functional complexity of the glacier–stream system interface. Here we propose quantifying the diurnal cycle amplitude of the streamflow to determine the glacial influence in glacierized catchments. We performed water-level measurements using water pressure loggers over 10 months at 30 min time steps in 15 stream sites in 2 glacier-fed catchments in the Ecuadorian Andes (> 4000 m a.s.l.) where no perennial snow cover is observed outside the glaciers. For each stream site, we performed wavelet analyses on water-level time series, determined the scale-averaged wavelet power spectrum at 24 h scale and defined three metrics, namely the power, frequency and temporal clustering of the diurnal flow variation. The three metrics were then compared to the percentage of the glacier cover in the catchments, a metric of glacial influence widely used in the literature. As expected, we found that the diurnal variation power of glacier-fed streams decreased downstream with the addition of non-glacial tributaries. We also found that the diurnal variation power and the percentage of the glacier cover in the catchment were significantly positively correlated. Furthermore, we found that our method permits the detection of glacial signal in supposedly non-glacial sites, thereby revealing glacial meltwater resurgence. While we specifically focused on the tropical Andes in this paper, our approach to determine glacial influence may have potential applications in temperate and arctic glacierized catchments. The measure of diurnal water amplitude therefore appears as a powerful and cost-effective tool to understand the hydrological links between glaciers and hydrosystems better and assess the consequences of rapid glacier shrinking.
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Roberts, J. B., and N. M. C. Dacunha. "Roll Motion of a Ship in Random Beam Waves: Comparison Between Theory and Experiment." Journal of Ship Research 29, no. 02 (June 1, 1985): 112–26. http://dx.doi.org/10.5957/jsr.1985.29.2.112.
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The results of an experimental study of a ship rolling in random beam waves at zero speed are presented. The experiments were conducted in a large wave tank using a 1:20 scale model of the fisheries protection vessel Sulisker. By digitally processing the roll response measurements, obtained over long periods of time, estimates of the probability distribution of the roll peak amplitudes were obtained and compared with some corresponding theoretical predictions. The theory was found to give good agreement with the experimental findings for four different wave elevation spectra. In particular, the experimentally observed deviation from the Rayleigh distribution at high peak amplitudes was correctly predicted by the theory. This deviation is largely due to the pronounced nonlinear character of the roll damping.
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REMONDINI, D., N. NERETTI, C. FRANCESCHI, P. TIERI, J. M. SEDIVY, L. MILANESI, and G. C. CASTELLANI. "NETWORKS FROM GENE EXPRESSION TIME SERIES: CHARACTERIZATION OF CORRELATION PATTERNS." International Journal of Bifurcation and Chaos 17, no. 07 (July 2007): 2477–83. http://dx.doi.org/10.1142/s0218127407018543.
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We address the problem of finding large-scale functional and structural relationships between genes, given a time series of gene expression data, namely mRNA concentration values measured from genetically engineered rat fibroblasts cell lines responding to conditional cMyc proto-oncogene activation. We show how it is possible to retrieve suitable information about molecular mechanisms governing the cell response to conditional perturbations. This task is complex because typical high-throughput genomics experiments are performed with high number of probesets (103–104 genes) and a limited number of observations (< 102 time points). In this paper, we develop a deepest analysis of our previous work [Remondini et al., 2005] in which we characterized some of the main features of a gene-gene interaction network reconstructed from temporal correlation of gene expression time series. One first advancement is based on the comparison of the reconstructed network with networks obtained from randomly generated data, in order to characterize which features retrieve real biological information, and which are instead due to the characteristics of the network reconstruction method. The second and perhaps more relevant advancement is the characterization of the global change in co-expression pattern following cMyc activation as compared to a basal unperturbed state. We propose an analogy with a physical system in a critical state close to a phase transition (e.g. Potts ferromagnet), since the cell responds to the stimulus with high susceptibility, such that a single gene activation propagates to almost the entire genome. Our result is relative to temporal properties of gene network dynamics, and there are experimental evidence that this can be related to spatial properties regarding the global organization of chromatine structure [Knoepfler et al., 2006].
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Nemțeanu, Marcela-Sefora, Vasile Dinu, Rebeka-Anna Pop, and Dan-Cristian Dabija. "PREDICTING JOB SATISFACTION AND WORK ENGAGEMENT BEHAVIOR IN THE COVID-19 PANDEMIC: A CONSERVATION OF RESOURCES THEORY APPROACH." E+M Ekonomie a Management 25, no. 2 (June 2022): 23–40. http://dx.doi.org/10.15240/tul/001/2022-2-002.
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The rapid spread of the COVID-19 pandemic has forced organizations to impose physical distancing restrictions on employees and to practice teleworking on a large scale. Adapting to the new context has generated an increase in job insecurity, and a decrease in employee productivity concerning task completion, boosting stress and counterproductive work behavior. Although the challenges employees face when carrying out their activities and work-related responsibilities, together with an understanding of the factors generating counterproductive work behaviors and job insecurity have been intensely studied in the literature, their manifestation and impact within organizations in the context of the COVID-19 pandemic is barely covered. This paper aims to fill this research gap by evaluating the way internal vision communication, employee reward systems, knowledge, and skills capitalization, and the maintaining of task performance can diminish counterproductive work behaviors and job insecurity generated by the COVID-19 pandemic, influencing employee satisfaction and behavior in this stress-inducing context. The responses collected from 863 Romanian employees are modelled with the help of structural equations in SmartPLS. The results show that in the case of counterproductive work behavior, employee satisfaction diminishes, while efficient performance of tasks and responsibilities, knowledge and skills capitalization, internal vision communication, and the existence of an employee reward system for employee input can all generate greater organizational attachment. Job satisfaction mediates the influence of performance, internal marketing, and counterproductive work behavior in employees’ attachment towards their respective organizations. The paper contributes to the development of the Conservation of Resources Theory, highlighting, in the context of the COVID-19 pandemic, ways in which employee satisfaction and work engagement behavior can be enhanced, thus contributing to diminishing counterproductive work behaviors, and fostering a pleasant and safe work environment.
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McCrindle, Rachel, Holly Robson, Lotte Meteyard, Malcom Sperrin, Andy Smith, Moyra Pugh, and Maitreyee Wairagkar. "MaLT – Combined Motor and Language Therapy Tool for Brain Injury Patients Using Kinect." Methods of Information in Medicine 56, no. 02 (2017): 127–37. http://dx.doi.org/10.3414/me16-02-0015.
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Summary Background: The functional connectivity and structural proximity of elements of the language and motor systems result in frequent co-morbidity post brain injury. Although rehabilitation services are becoming increasingly multidisciplinary and “integrated”, treatment for language and motor functions often occurs in isolation. Thus, behavioural therapies which promote neural reorganisation do not reflect the high inter-system connectivity of the neurologically intact brain. As such, there is a pressing need for rehabilitation tools which better reflect and target the impaired cognitive networks. Objectives: The objective of this research is to develop a combined high dosage therapy tool for language and motor rehabilitation. The rehabilitation therapy tool developed, MaLT (Motor and Language Therapy), comprises a suite of computer games targeting both language and motor therapy that use the Kinect sensor as an interaction device. The games developed are intended for use in the home environment over prolonged periods of time. In order to track patients’ engagement with the games and their rehabilitation progress, the game records patient performance data for the therapist to interrogate. Methods: MaLT incorporates Kinect-based games, a database of objects and language parameters, and a reporting tool for therapists. Games have been developed that target four major language therapy tasks involving single word comprehension, initial phoneme identification, rhyme identification and a naming task. These tasks have 8 levels each increasing in difficulty. A database of 750 objects is used to programmatically generate appropriate questions for the game, providing both targeted therapy and unique game-play every time. The design of the games has been informed by therapists and by discussions with a Public Patient Involvement (PPI) group. Results: Pilot MaLT trials have been conducted with three stroke survivors for the duration of 6 to 8 weeks. Patients’ performance is monitored through MaLT’s reporting facility presented as graphs plotted from patient game data. Performance indicators include reaction time, accuracy, number of incorrect responses and hand use. The resultant games have also been tested by the PPI with a positive response and further suggestions for future modifications made. Conclusion: MaLT provides a tool that innovatively combines motor and language therapy for high dosage rehabilitation in the home. It has demonstrated that motion sensor technology can be successfully combined with a language therapy task to target both upper limb and linguistic impairment in patients following brain injury. The initial studies on stroke survivors have demonstrated that the combined therapy approach is viable and the outputs of this study will inform planned larger scale future trials.
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Yan, Juchao, David C. Grills, and Tomoyasu Mani. "Dynamic Excitons in Nitrile-Functionalized Ladder-Type Oligo(p-Phenylene)s By Pulse Radiolysis Coupled with Time-Resolved Infrared Spectroscopy." ECS Meeting Abstracts MA2022-01, no. 13 (July 7, 2022): 885. http://dx.doi.org/10.1149/ma2022-0113885mtgabs.
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Research and development efforts toward organic solar cells (OSCs) for large-scale power generation have continued unabated throughout the world. In recent years, OSCs based on π-conjugated polymers and small molecules have received increasing interest due to favorable electronic properties, component versatility, and low production and installation costs. Despite the progress, many improvements are still needed prior to widespread commercialization, involving device efficiency, lifetime, and cost. Of these, increasing device efficiency, particularly power conversion efficiency (PCE), is the most challenging task. The currently achievable PCE, for example, is only 17.3%.1 The key to achieving high PCE is the search for new organic conjugated molecules that are capable of harvesting light, and transferring and transporting charges promptly and efficiently. This requires a full understanding of how electrons and holes are localized and delocalized in organic conjugated molecules. Using time-resolved infrared (TRIR) detection combined with pulse radiolysis, Mani and co-workers2 have measured experimentally the degree of localization of an excess electron in a series of nitrile-functionalized oligofluorenes by the spectral shifts of nitrile vibrations. The nitrile vibrational bands in anions respond sensitively to the degree of electron delocalization (IR shifts) and the structural changes (IR linewidth). The electron is found to move back and forth within the oligomers, likely controlled by the movement of dihedral angles between monomer units. Unlike the non-coplanarity of the fluorenyl-fluorenyl backbone in oligofluorenes, the rigid and planar structure of ladder-type, oligo(p-phenylene)s (Scheme 1)3 would facilitate π-electron delocalization and thus improve the multiphoton absorption response. Such a structure would also increase photoluminescence efficiency with enhanced thermal and photochemical stability. To investigate the coupling between charge distribution and vibrational motion and vibronic coupling, we incorporate nitrile group in each compound as the infrared reporter group. In this talk, we report our molecular syntheses and characterizations of two of the title compounds (L3PCN and L4PCN, both neutral compounds and their radical anions) by TRIR followed by pulse radiolysis. Having no flexible dihedral angles, L3PCN and L4PCN exhibit sharper IR bands of the nitrile vibration than the oligofluorenes with the same number of benzene rings and some dihedral angles. Our results further demonstrate that the linewidth of the nitrile vibration, together with the IR shifts and intensities, reports on structural and accompanying electronic fluctuations,2 that is, on the dynamic excitons. References (1) Meng, L. X.; et al. Science 2018, 361, 1094. (2) Mani, T.; et al. Journal of the American Chemical Society 2015, 137, 10979. (3) Scherf, U.; et al. Makromolekulare Chemie-Rapid Communications 1991, 12, 489. Figure 1