1,564 research outputs found

    Constructivist Perspective on Developing a Multidimensional Blended Teaching Model Fostering Deep Learning

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    To promote high-quality development of higher education, it is imperative to facilitate studentsā€™ transition from surface learning to deep learning. Compared with surface learning that focuses on rote memorization, deep learning emphasizes meaningful learning based on understanding and transfer. It involves three progressively advanced cognitive stages of knowing: "learning for understanding," "learning for application," and "learning for innovation," which ultimately enable the internalization, transfer, and creative application of knowledge. How to foster deep learning in students has been an urgent issue of higher education. This study, grounded in constructivist learning theory, explores a multidimensional blended teaching model fostering deep learning. It also develops an evaluation system assessing learning outcomes from the perspectives of ideological, political and moral education, knowledge, and competencies. We conducted an empirical study to test the effectiveness of this multidimensional blended teaching model. Findings will provide theoretical and practical implications for teaching reforms of similar courses

    Characterizing First Arrival Position Channels: Noise Distribution and Capacity Analysis

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    This paper addresses two fundamental problems in diffusive molecular communication: characterizing the first arrival position (FAP) density and bounding the information transmission capacity of FAP channels. Previous studies on FAP channel models, mostly captured by the density function of noise, have been limited to specific spatial dimensions, drift directions, and receiver geometries. In response, we propose a unified solution for identifying the FAP density in molecular communication systems with fully-absorbing receivers. Leveraging stochastic analysis tools, we derive a concise expression with universal applicability, covering any spatial dimension, drift direction, and receiver shape. We demonstrate that several existing FAP density formulas are special cases of this innovative expression. Concurrently, we establish explicit upper and lower bounds on the capacity of three-dimensional, vertically-drifted FAP channels, drawing inspiration from vector Gaussian interference channels. In the course of deriving these bounds, we unravel an explicit analytical expression for the characteristic function of vertically-drifted FAP noise distributions, providing a more compact characterization compared to the density function. Notably, this expression sheds light on a previously undiscovered weak stability property intrinsic to vertically-drifted FAP noise distributions.Comment: 30 pages; 3 figures, 1 table; this paper is submitted to IEEE Transactions on Communication

    Enhanced bandwidth nonlinear resonance electromagnetic human motion energy harvester using magnetic-springs and ferrofluid

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    An enhanced bandwidth nonlinear resonant electromagnetic energy harvester has been designed to harness low frequency energy from basic human motion. Some vertical stacked cylindrical permanent magnets (PMs) constitute the inertial mass of the proposed harvester, which is suspended axially by two magnetic-springs and circumferentially by ferrofluid within a carbon fiber tube. In order to widen the frequency band and improve harvesting efficiency, two PMs are respectively fixed on the two end caps of the carbon fiber tube, so as to form two magnetic-springs with variable stiffness by cooperating with the PM stack. The self-assembled ferrofluid around the PM stack acts as its bearing system to minimize any friction during its movement. Copper wire are wrapped outside the tube to form the armature winding. The stiffness characteristic of the magnetic-springs and the optimum equilibrium position and number of windings have been determined by finite element method (FEM) analysis. As a proof of concept, a portable prototype of the proposed energy harvester that weighs 110g and with a volume of only 37.7cm 3^3 is fabricated. A series of experiments are carried out and the results show that the frequency band of the harvester becomes wider as the external vibration intensity increases. In addition, the effectiveness of ferrofluid in reducing friction is demonstrated under walking and running conditions. Without ferrofluid, the maximum average outputs are 10.15 mW and 32.53 mW respectively for walking and running. With ferrofluid, the maximum outputs are 17.72 mW and 54.61 mW, representing an increase of 74.58% and 67.88%, respectively. Furthermore, the prototype exhibits an average power density of 1.45 mW/cm 3^3 during running motions, which compares favorably with existing harvesters used in low power wearable devices

    Diabetes and Health Outcomes Among Older Taiwanese with Hip Fracture

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    Abstract Objective: Hip fracture tremendously impacts functional abilities for the elderly with high morbidity and mortality; recovery is compromised by co-morbidities. Diabetes mellitus is a common co-morbidity for the aging population, but little is known about the influence of diabetes on outcomes of the Asian elderly with hip fracture. Research Design and Methods: This study was a secondary analysis of data on 242 community-dwelling elders with hip fracture from three previous longitudinal studies. Sixty-one cases (25.2%) had diabetes. Outcomes were measured by the Chinese Barthel Index, Medical Outcomes Study Short Form-36 Taiwan version, and analyzed by the generalized estimating equation approach to examine how diabetes influenced hip-fractured elders' mortality, service utilization, mobility, daily activities, and health-related quality of life during the first 12 months after postsurgical discharge in Taiwan. Results: Hip-fractured elderly with diabetes had a significantly higher mortality rate (22.6% vs. 10.3%, p=0.03) during the first year following discharge, and significantly higher readmission rate (10.0% vs. 2.5%, p=0.04) from the first to third month following discharge than those without diabetes. After controlling for covariates, elderly participants without diabetes had an overall 2.2 times (confidence interval [CI]=1.15?4.21) greater odds of recovery in walking ability and better reported general health (?=9.33; p=0.01) and physical functioning (?=7.26; p=0.02) than those with diabetes during the first year after discharge. Conclusions: Diabetes negatively influenced outcomes of elderly patients with hip fracture. The results may provide a reference for developing interventions for hip-fractured elders with diabetes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98472/1/rej%2E2011%2E1308.pd

    Seismologically determined bedload flux during the typhoon season

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    Continuous seismic records near river channels can be used to quantify the energy induced by river sediment transport. During the 2011 typhoon season, we deployed a seismic array along the Chishan River in the mountain area of southern Taiwan, where there is strong variability in water discharge and high sedimentation rates. We observe hysteresis in the high-frequency (5ā€“15ā€…Hz) seismic noise level relative to the associated hydrological parameters. In addition, our seismic noise analysis reveals an asymmetry and a high coherence in noise cross-correlation functions for several station pairs during the typhoon passage, which corresponds to sediment particles and turbulent flows impacting along the riverbed where the river bends sharply. Based on spectral characteristics of the seismic records, we also detected 20 landslide/debris flow events, which we use to estimate the sediment supply. Comparison of sediment flux between seismologically determined bedload and derived suspended load indicates temporal changes in the sediment flux ratio, which imply a complex transition process from the bedload regime to the suspension regime between typhoon passage and off-typhoon periods. Our study demonstrates the possibility of seismologically monitoring river bedload transport, thus providing valuable additional information for studying fluvial bedrock erosion and mountain landscape evolution

    Seismology-based early identification of dam-formation landquake events

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    Flooding resulting from the bursting of dams formed by landquake events such as rock avalanches, landslides and debris flows can lead to serious bank erosion and inundation of populated areas near rivers. Seismic waves can be generated by landquake events which can be described as time-dependent forces (unloading/reloading cycles) acting on the Earth. In this study, we conduct inversions of long-period (LP, period ā‰„20ā€‰s) waveforms for the landquake force histories (LFHs) of ten events, which provide quantitative characterization of the initiation, propagation and termination stages of the slope failures. When the results obtained from LP waveforms are analyzed together with high-frequency (HF, 1ā€“3ā€‰Hz) seismic signals, we find a relatively strong late-arriving seismic phase (dubbed Dam-forming phase or D-phase) recorded clearly in the HF waveforms at the closest stations, which potentially marks the time when the collapsed masses sliding into river and perhaps even impacting the topographic barrier on the opposite bank. Consequently, our approach to analyzing the LP and HF waveforms developed in this study has a high potential for identifying five dam-forming landquake events (DFLEs) in near real-time using broadband seismic records, which can provide timely warnings of the impending floods to downstream residents

    High efficiency silicon nanodisk laser based on colloidal CdSe/ZnS QDs

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    Using colloidal CdSe/ZnS quantum dots in the submicron-sized silicon disk cavity, we have developed a visible wavelength nanodisk laser that operates under extremely low threshold power at room temperature. Time-resolved photoluminescence (PL) of QDs; nanodisk by e-beam lithography. Observation of lasing action at 594 nm wavelength for quantum dots on a nanodisk (750 nm in diameter) cavity and an ultra-low threshold of 2.8 ĀµW. From QD concentration dependence studies we achieved nearly sevenfold increase in spontaneous emission (SE) rate. We have achieved high efficient and high SE coupling rate in such a QD nanodisk laser
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