151 research outputs found
A Comparative Study of Grade 12 Students’ Use of Direct and Indirect Second Language Learning Strategies According to Their Gender and Classes at Luchuan High School, Guangxi, China
This research mainly focused on the Chinese Grade 12 students’ use of second language learning strategies during the academic year 2016-2017, at Luchuan High school, Guangxi, China. A total of 120 students from grade 12 in this study. The data were collected based on the questionnaire of learning strategies for English learning. The study found that Grade 12 students used both direct strategies and indirect strategies for their English learning at a medium level; the use of overall learning strategies was also at a medium level. There was no significantly difference of students' use of second language learning strategies according to their gender, the direct strategies and indirect strategies. There is a significant difference of students' use of second language learning strategies according to their classes
A Survey on Consortium Blockchain Consensus Mechanisms
Blockchain is a distributed ledger that is decentralized, immutable, and
transparent, which maintains a continuously growing list of transaction records
ordered into blocks. As the core of blockchain, the consensus algorithm is an
agreement to validate the correctness of blockchain transactions. For example,
Bitcoin is a public blockchain where each node in Bitcoin uses the Proof of
Work (PoW) algorithm to reach a consensus by competing to solve a puzzle.
Unlike a public blockchain, a consortium blockchain is an enterprise-level
blockchain that does not contend with the issues of creating a resource-saving
global consensus protocol. This paper highilights several state-of-the art
solutions in consensus algorithms for enterprise blockchain. For example, the
HyperLedger by Linux Foundation includes implementing Practical Byzantine Fault
Tolerance (PBFT) as the consensus algorithm. PBFT can tolerate a range of
malicious nodes and reach consensus with quadratic complexity. Another
consensus algorithm, HotStuff, implemented by Facebook Libra project, has
achieved linear complexity of the authenticator. This paper presents the
operational mechanisms of these and other consensus protocols, and analyzes and
compares their advantages and drawbacks.Comment: under submissio
SafeLight: A Reinforcement Learning Method toward Collision-free Traffic Signal Control
Traffic signal control is safety-critical for our daily life. Roughly
one-quarter of road accidents in the U.S. happen at intersections due to
problematic signal timing, urging the development of safety-oriented
intersection control. However, existing studies on adaptive traffic signal
control using reinforcement learning technologies have focused mainly on
minimizing traffic delay but neglecting the potential exposure to unsafe
conditions. We, for the first time, incorporate road safety standards as
enforcement to ensure the safety of existing reinforcement learning methods,
aiming toward operating intersections with zero collisions. We have proposed a
safety-enhanced residual reinforcement learning method (SafeLight) and employed
multiple optimization techniques, such as multi-objective loss function and
reward shaping for better knowledge integration. Extensive experiments are
conducted using both synthetic and real-world benchmark datasets. Results show
that our method can significantly reduce collisions while increasing traffic
mobility.Comment: Accepted by AAAI 2023, appendix included. 9 pages + 5 pages appendix,
12 figures, in Proceedings of the Thirty-Seventh AAAI Conference on
Artificial Intelligence (AAAI'23), Feb 202
FAST: Improving Controllability for Text Generation with Feedback Aware Self-Training
Controllable text generation systems often leverage control codes to direct
various properties of the output like style and length. Inspired by recent work
on causal inference for NLP, this paper reveals a previously overlooked flaw in
these control code-based conditional text generation algorithms. Spurious
correlations in the training data can lead models to incorrectly rely on parts
of the input other than the control code for attribute selection, significantly
undermining downstream generation quality and controllability. We demonstrate
the severity of this issue with a series of case studies and then propose two
simple techniques to reduce these correlations in training sets. The first
technique is based on resampling the data according to an example's propensity
towards each linguistic attribute (IPS). The second produces multiple
counterfactual versions of each example and then uses an additional feedback
mechanism to remove noisy examples (feedback aware self-training, FAST). We
evaluate on 3 tasks -- news headline, meta review, and search ads generation --
and demonstrate that FAST can significantly improve the controllability and
language quality of generated outputs when compared to state-of-the-art
controllable text generation approaches
Enhanced variable reluctance energy harvesting for self-powered monitoring
With the rapid development of microelectronic technology, wireless sensor nodes have been widely used in rotational equipment for health condition monitoring. However, for many low-frequency applications, there still remains an open issue of harvesting sufficient electrical energy to provide long-term service. Therefore, in this paper an enhanced variable reluctance energy harvester (EVREH) is proposed for self-powered health monitoring under low-frequency rotation conditions. A periodic arrangement of magnets and teeth is employed to achieve frequency up-conversion for performance enhancement under a specific space constraint. In addition, the permeance of the air gap is calculated by the combined magnetic field division and substituting angle method, and the output model of the EVREH is derived for parametric analysis based on the law of electromagnetic induction. Simulations and experimental evaluations under a range of structural parameters are then carried out to verify the effectiveness of the proposed model and investigate the output performance of the proposed harvester. The experimental results indicate that the proposed energy harvester could produce a voltage of 8.7 V and a power of 726 mW for a rotational speed of 200 rpm, with a power density of 0.545 mW/(cm3∙Hz2). Moreover, a self-powered wireless sensing system based on the proposed energy harvester is demonstrated, obtaining a vibration spectrum of the rotating motor and stator which can determine the health state of the system during low rotational speeds. Therefore, this autonomous self-sensing experiment verifies the potential of the EVREH for self-powered monitoring in low-frequency rotation applications.</p
Self-organized Voids Revisited: Experimental Verification of the Formation Mechanism*
In this paper, several experiments were conducted to further clarify the
formation mechanism of self organized void array induced by a single laser
beam, including energy-related experiments, refractive-index-contrast-related
experiments, depth-related experiments and effective-numerical-aperture
experiment. These experiments indicate that the interface spherical aberration
is indeed responsible for the formation of void arrays
What Are the Effects of Self-Regulation Phases and Strategies for Chinese Students? A Meta-Analysis of Two Decades Research of the Association Between Self-Regulation and Academic Performance
Background: Self-regulated learning refers to the monitoring and controlling of one's own cognitive performance before, during, and after a learning episode. Previous literature suggested that self-regulated learning had a significant relationship with academic achievement, but not all self-regulated learning strategies exerted the same influences. Using an invalid strategy may waste the limited psychological resources, which will cause the ego depletion effect. The present meta-analysis study intended to search for the best self-regulated learning strategies and inefficient strategies for Chinese students in elementary and secondary school, and analyzed the critical phases of self-regulated learning according to Zimmerman's theory. The moderating effects of gender, grade, and publication year were also analyzed.Methods: Empirical studies which conducted in real teaching situations of elementary and secondary education were systematically searched using Chinese academic databases. Studies focused on undergraduate students, students of special education, or online learning environments were excluded. Fifty-five cross-sectional studies and four intervention studies (which generated 264 independent samples) were included with a total sample size of 23,497 participants. Random effects model was chosen in the current meta-analysis, and publication bias was also examined.Results: The results indicated that the overall effect size of self-regulated learning on academic achievement was small for primary and secondary school students in China. The effect sizes of self-efficacy, task strategies, and self-evaluation were relatively higher than other strategies. Self-regulated learning strategies have the largest effect size on science disciplines (including mathematics and physics). Performance phase and self-reflection phase are key phases of self-regulated learning. From 1998 to 2016, the effect size between self-regulated learning and academic achievement was gradually decreasing.Conclusions: The main findings of the current study showed that self-efficacy, task strategies, and self-evaluation were key self-regulated learning strategies for Chinese students. Performance phase and self-reflection phase played significant roles in the process of self-regulated learning. Future studies need to include more intervention studies with rigorous treatment fidelity control and provide more empirical evidence from online learning, so as to compare the different effects of self-regulated learning between traditional education and online education
Identification of the Germline Mutation Profile in Esophageal Squamous Cell Carcinoma by Whole Exome Sequencing
Background: Esophageal squamous cell carcinoma (ESCC) is associated with poor prognosis and occurs with high frequency in China. The germline mutation profile in ESCC remains unclear, and therefore, the discovery of oncogenic alterations in ESCC is urgently needed. This study investigates the germline mutation profile and reveals associations among genotype-environment interactions in ESCC.Methods: Whole exome sequencing and follow-up analysis were performed in 77 matched tumor-normal ESCC specimens to examine the germline profiles. Additionally, associations among genotype-environment interactions were investigated.Results: We identified 84 pathogenic/likely pathogenic mutations and 51 rare variants of uncertain significance (VUS). Twenty VUS with InterVar evidence of a score of moderate pathogenicity (PM) 2/PM2+ supporting pathogenicity (PP) 1 were found to have pathogenic significance. CYP21A2 was the most frequently mutated gene, and the p.Gln319* variant was identified in 6.5% (5/77) of patients. The TP53 p.V197E mutation, located within the DNA binding domain, was found in 1.3% (1/77) of patients. In total, the 11.7% (9/77) of individuals with homologous recombination (HR) VUS were more likely to have well-differentiated tumors than those without (P = 0.003). The degree of lymph node metastasis was correlated with homologous recombination deficiency (HRD) and VUS group (P < 0.05). Moreover, the 10.4% (8/77) of individuals with mismatch repair (MMR) VUS had a higher tumor mutational burden (TMB), although the correlation was not significant.Conclusions: Our study identified the germline mutation profiles in ESCC, providing novel insights into the molecular pathogenesis of this disease. Our results may also serve as a useful resource for the exploration of the underlying mechanism of ESCC and may provide information for the prevention, diagnosis and risk management of ESCC
Comparison of the asymmetries in muscle mass, biomechanical property and muscle activation asymmetry of quadriceps femoris between patients with unilateral and bilateral knee osteoarthritis
Background: More and more attention has been paid to the research of muscle mass and muscle quality of quadriceps femoris (QF) in knee osteoarthritis (KOA). This study aimed to explore the asymmetric changes of muscle mass, biomechanical property and muscle activation in the inter-limbs QF of KOA patients, and tried to provide a novel insight for the evaluation, prevention and treatment of KOA.Methods: A total of 56 Participants with unilateral or bilateral KOA were included in this study: 30 patients with unilateral pain and 26 patients with bilateral pain were assigned to the bilateral group (BG) and unilateral group (UG), respectively. The symptom severity of bilateral lower limbs was evaluated by visual analogue scale, and the relatively serious leg (RSL) and relatively moderate leg (RML) were classified. The thickness of rectus femoris (RF), vastus intermedius (VI), vastus medialis (VM) and vastus lateralis (VL) were measured by ultrasound. The Shear wave elastography (SWE) techniqie was used to measure the shear modulus of RF, VM and VL. Surface electromyography (sEMG) was used to assess the root mean square (RMS) of the RF, VM, and VL during straight leg raising in a sitting position and squatting task. We calculated the asymmetry indexes of inter-limbs for the corresponding indices of the measured muscles.Result: Thickness of RF, VI and VL of RSL was lower than those on RML (p < 0.05), and thickness of VM was lower more significant (p < 0.01). Thickness of RF, VI and VL of RSL was also lower than those of RML in BG (p < 0.05), however, there was no significant difference in VM thickness (p > 0.05). There were no significant difference in Asymmetry indexes of all measured muscle thickness between the two groups (p > 0.05). The Shear modulus of RF, VM, and VL in the RML of UG and BG was higher than those in the RSL (p < 0.05). In sitting and straight leg raising task, the RMS of RF, VM and VL in RML were higher than those in RSL, UG and BG both showed this trend (p < 0.05). About squatting task, in UG, the RMS of the three muscles in RML of patients were also higher than those in the RSL (p < 0.05). However, the difference was not significant in BG (p > 0.05). In the straight leg raising task, the asymmetry indexes of RMS in RF, VM, and VL of both the two groups were positively correlated with VAS scores (p < 0.05).Conclusion: The muscle thickness, shear modulus and muscle activation electromyography of QF in RML were higher than those of RSL in unilateral KOA patients. The VM of RML in bilateral KOA patients may show muscle thickness degeneration earlier, which is closer to the VM of RSL. The shear modulus of RF, VM, and VL were higher on the RML side during the single-leg task, but there may be passive compensation for muscle activation in both lower limbs during the bipedal task. In conclusion, there is a general asymmetry of QF muscle mass, biomechanics Characteristic and performance in patients with KOA, which may provide new ideas for the assessment, treatment and rehabilitation of the disease
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