Predicting digital informal learning: an empirical study among Chinese University students

Tao He,Chang Zhu,Frederik Questier 서울대학교 교육연구소 2018 Asia Pacific Education Review Vol.19 No.1

Although the adoption of digital technology has gained considerable attention in higher education, currently research mainly focuses on implementation in formal learning contexts. Investigating what factors influence students’ digital informal learning is still unclear and limited. To understand better university students’ digital informal learning (DIL), this study proposed a model based on decomposed theory of planned behavior to investigate students’ behavioral intention to DIL. Different aspects of DIL behavior were further explored, through examining behaviors of cognitive learning, metacognitive learning, and social and motivation learning. This study also integrated digital competence as a new construct into the model, along with other variables to test the proposed model. A sample of 335 students selected from three universities in China took part in this study. The partial least square structural equation modeling was applied to analyze the data. The results provide support and better understanding for the importance of motivation factors such as digital competence and compatibility to explain students’ DIL.

Modeling and Parameter Estimation of Particle Swarm Optimization Algorithm for Smart Power Grid

He Tao,Liang Zhidong,Ye Xinquan,Sun Shufeng,Pang Jihong 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.6

This paper analysis the electric power communication network structure and performance requirements. To investigate the power communication backbone network and network power substation general way, and in electric power communication network delay, error rate, network bandwidth demand were analyzed. The for prevalent in electric power communication network is not a fully meshed network, explore artificially cobweb logic change principle and system method, artificial transform sheet mesh to the standard web, and making use of the cobweb, based on the characteristics of network fast routing. In order to better in the smart grid communication network using artificially cobweb routing algorithm, for the smart grid in the presence of irregular mesh network, this paper presents a kind of the mesh network into logical artificially cobweb network general standardization method. The principle of combination of label switching, this paper presents artificially cobweb source routing algorithm, expounds the artificially cobweb routing algorithm of label switching and label update mechanism, and artificially cobweb routing algorithm balancing routing method and routing method is described in detail.

Partitioned coupling strategies for fluid-structure interaction with large displacement: Explicit, implicit and semi-implicit schemes

Tao He 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.20 No.3

In this paper the unsteady fluid-structure interaction (FSI) problems with large structuraldisplacement are solved by partitioned solution approaches in the arbitrary Lagrangian-Eulerian finiteelement framework. The incompressible Navier-Stokes equations are solved by the characteristic-based split(CBS) scheme. Both a rigid body and a geometrically nonlinear solid are considered as the structural models. The latter is solved by Newton-Raphson procedure. The equation governing the structural motion isadvanced by Newmark-β method in time. The dynamic mesh is updated by using moving submesh approachthat cooperates with the ortho-semi-torsional spring analogy method. A mass source term (MST) isintroduced into the CBS scheme to satisfy geometric conservation law. Three partitioned coupling strategiesare developed to take FSI into account, involving the explicit, implicit and semi-implicit schemes. Thesemi-implicit scheme is a mixture of the explicit and implicit coupling schemes due to the fluid projectionsplitting. In this scheme MST is renewed for interfacial elements. Fixed-point algorithm with Aitken’s Δ2method is carried out to couple different solvers within the implicit and semi-implicit schemes. Flow-induced vibrations of a bridge deck and a flexible cantilever behind an obstacle are analyzed to test theperformance of the proposed methods. The overall numerical results agree well with the existing data,demonstrating the validity and applicability of the present approaches.

Metal-free photocatalytic trifluoromethylative pyridylation of unactivated alkenes

He, Yu-Tao,Kang, Dahye,Kim, Inwon,Hong, Sungwoo The Royal Society of Chemistry 2018 GREEN CHEMISTRY Vol.20 No.22

<P>An efficient, transition metal-free trifluoromethylative pyridylation of unactivated alkenes was achieved by visible-light-induced photoredox catalysis employing CF3SO2Na and a pyridinium salt in the presence of eosin Y as a photoredox catalyst. The overall process is thought to occur by the selective addition of an electrophilic CF3 radical to the alkene substrate to provide an alkyl radical intermediate, which subsequently engages in an addition to the pyridinium salt. This three-component photocatalytic strategy circumvents traditional multistep procedures and readily affords synthetically and biologically important trifluoromethyl- and pyridyl-containing frameworks.</P>

Load Interval Prediction of the Power System based on Type-2 Fuzzy Theory

He Tao,Liang Zhidong,Pang Jihong,Ye Xianquan,Yuan Jinxin 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.2

According to the power load has strong randomness and difficult to forecast, the introduction of the two types of fuzzy logic in order to improve the prediction accuracy. The interval type two non-single valued two type Mamdani fuzzy model for power load time series forecasting, and reverse the spread of a similarity of a singular value decomposition iterative blending algorithm to simplify the redundant rules in the model of fuzzy sets and redundant fuzzy rules, in order to eliminate the adverse effects. For ordinary type-2 fuzzy sets, uncertainty of the trace and once the membership function is the most important factor, therefore in the calculation formula for construction of two kinds of measure when considering these two factors; analysis of the ordinary type-2 fuzzy inclusion degree properties; discussed two kinds of conversion between the new measure of the relationship, revealing its internal relations; finally through an example to verify the performance of the new measure ordinary type-2, and the fuzzy similarity and Yang Shih clustering method combining cluster analysis used in Gauss plain type-2 fuzzy sets, obtained the reasonable clustering results, verify the rationality of the new measure and effectiveness.

One-pot bifunctionalization of unactivated alkenes, P(O)-H compounds, and <i>N</i>-methoxypyridinium salts for the construction of β-pyridyl alkylphosphonates

He, Yu-Tao,Won, Joonghee,Kim, Jiyun,Park, Bohyun,Kim, Taehwan,Baik, Mu-Hyun,Hong, Sungwoo The Royal Society of Chemistry 2018 ORGANIC CHEMISTRY FRONTIERS Vol.5 No.17

<P>β-Pyridylphosphines consisting of vicinal pyridine and phosphine groups possess soft acceptor properties of phosphines and hard σ-donor features of pyridines. An efficient method for the synthesis of β-pyridyl alkylphosphonates was developed <I>via</I> a three-component reaction between P(O)-H compounds, alkenes and <I>N</I>-methoxypyridinium salts under mild conditions. The reaction is thought to occur by the addition of a phosphonyl radical to the alkene to form alkyl radical intermediate, which goes on to add to the <I>N</I>- <I>N</I>-methoxypyridinium salt. Solvation plays an important role and DFT calculations suggest that the solvation effect is critical in the first step where an alkyl radical intermediate is formed by coupling the phosphonyl radical and the alkene substrate. A plausible mechanism is proposed based on DFT calculations and this novel methodology is applied to a variety of heteroarenium salts and alkene substrates to prepare various synthetically and biologically important β-pyridyl alkylphosphonates.</P>

Experimental Study on the Migration and Clogging of Fine Particles in Coarse-Grained Soil with Seepage

Tao He,Haitao Mao,Chao Zhang,Yi Gu,Bin Yang 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.2

The migration and clogging of fine particles in the pores of coarse-grained soil with seepage is of great significance to reduce the leakage of soil at the dam base and lower the permeability of soil. Therefore, the homemade infiltration test device was used to test the infiltration and clogging of soil samples with different particle size ratios D15/d85 (D15 represents the particle size corresponding to the cumulative percentage content of soil particles smaller than a certain particle size in the coarse particles which is 15%, and d85 represents the particle size corresponding to the cumulative percentage content of soil particles smaller than a certain particle size in the fine particles group which is 85%). The factors affecting the deposition of fine particles in coarse-grained soil and the characteristics of fine particle migration and penetration were analyzed. The clogging of coarse-grained soil, hydraulic gradient and pore changes characteristics before and after clogging were studied. The results show that: 1) The main factor affecting the retention of fine particles in coarse-grained soil is the particle size ratio, and the retention rules conforms to the Peak-Gauss function relationship. The penetration law of fine particles satisfies the Logistic function relationship, which can directly predict the internal clogging of coarse-grained soil. 2) The particle size ratio is the main factor affecting the blockage in each mode, followed by the influence of the water head, When the particle size ratio is less than 13.10, the clogging ratio decreases with the increase of particle size ratio, and the hydraulic gradient increases with the increase of particle size ratio. When is greater than 13.10, the clogging ratio increases with the increase of particle size ratio, and the hydraulic gradient decreases with the increase of particle size ratio. 3) The degree of clogging in coarse-grained soil is closely related to the change in porosityand and can be judged according to the change of porosity in coarse-grained soil. The research results deepen the understanding of fine particle migration on the rules of coarse-grained soil clogging and can provide a theoretical basis for related engineering applications.

Resource Allocation for Device-to-Device Communications Underlaying Cellular Networks

Tao He,Xinquan Ye,Lieying Luo 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.5

Device-to-Device (D2D) communications potentially can improve spectrum efficiency because of resource spatial reuse. There are two possibilities for D2D resource allocation: contention-based resource allocation and scheduling-based resource allocation. In this paper, these resource allocation schemes are analyzed. Then, we propose a scheduling-based resource allocation that has the advantage of low scheduling overhead in addition to providing a common design for under the in-network coverage and out-of-network coverage. Simulation results show that the proposed algorithm can increase system throughput by exploring spatial reuse gain and maintain good proportional fairness among D2D communication pairs.

Research on Exploration and Analysis of Supply Chain Flexibility Measure Index

He Tao,Liang Zhidong,Ye Xinquan,Pang Jihong 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.11

The supply chain risk assessment and management system has been developed, people still do not determine the way to overcome all these risks, especially for high impact, low probability events, such as SARS and the outbreak of foot-and-mouth disease, or a centralized terrorist attacks. This is because the lack of historical data to make all kinds of prediction and statistical tools fail. The modern supply chain were more vulnerable to risk, supply chain risk mainly comes from many aspects of the internal and external environment, the supply chain industry products background, upstream and downstream supply chain relationship, decision support. In this paper, the establishment of a complete supply chain model with variable structure, through the simulation method for quantitative observation of supply chain flexibility curve, and abstract to describe the elastic curve of a set of parameters; after the design of simulation experiment to observe the different supply chain structure parameters (inventory level, supply chain, supplier selection for number of sources) influence supply chain resilience curve.

Partitioned coupling strategies for fluid-structure interaction with large displacement: Explicit, implicit and semi-implicit schemes

He, Tao Techno-Press 2015 Wind and Structures, An International Journal (WAS Vol.20 No.3

In this paper the unsteady fluid-structure interaction (FSI) problems with large structural displacement are solved by partitioned solution approaches in the arbitrary Lagrangian-Eulerian finite element framework. The incompressible Navier-Stokes equations are solved by the characteristic-based split (CBS) scheme. Both a rigid body and a geometrically nonlinear solid are considered as the structural models. The latter is solved by Newton-Raphson procedure. The equation governing the structural motion is advanced by Newmark-${\beta}$ method in time. The dynamic mesh is updated by using moving submesh approach that cooperates with the ortho-semi-torsional spring analogy method. A mass source term (MST) is introduced into the CBS scheme to satisfy geometric conservation law. Three partitioned coupling strategies are developed to take FSI into account, involving the explicit, implicit and semi-implicit schemes. The semi-implicit scheme is a mixture of the explicit and implicit coupling schemes due to the fluid projection splitting. In this scheme MST is renewed for interfacial elements. Fixed-point algorithm with Aitken's ${\Delta}^2$ method is carried out to couple different solvers within the implicit and semi-implicit schemes. Flow-induced vibrations of a bridge deck and a flexible cantilever behind an obstacle are analyzed to test the performance of the proposed methods. The overall numerical results agree well with the existing data, demonstrating the validity and applicability of the present approaches.