This book's importance is derived from three sources: careful conceptualization of teacher induction from historical, methodological, and international perspectives; systematic reviews of research literature relevant to various aspects of teacher induction including its social, cultural, and political contexts, program components and forms, and the range of its effects; substantial empirical studies on the important issues of teacher induction with different kinds of methodologies that exemplify future directions and approaches to the research in teacher induction.
Considering the effect of the local topology structure of an edge on cascading failures, we investigate the cascading reaction behaviors on scale-free networks with respect to small edge-based initial attacks. Our aim is to explore the relationship between some parameters and universal robustness characteristics against cascading failures on scale-free networks. We find by the theoretical analysis that the Baraba'si-Albert (BA) scale-free networks can reach the strongest robustness level against cascading failures when α + β = 1, where the robustness is (...) quantified by a transition from normal state to collapse. And the network robustness has a positive correlation with the average degree. We furthermore confirm by the numerical simulations these results. (shrink)
This co-edited volume compares Chinese and Western experiences of engineering, technology, and development. In doing so, it builds a bridge between the East and West and advances a dialogue in the philosophy of engineering. Divided into three parts, the book starts with studies on epistemological and ontological issues, with a special focus on engineering design, creativity, management, feasibility, and sustainability. Part II considers relationships between the history and philosophy of engineering, and includes a general argument for the necessity of dialogue (...) between history and philosophy. It continues with a general introduction to traditional Chinese attitudes toward engineering and technology, and philosophical case studies of the Chinese steel industry, railroads, and cybernetics in the Soviet Union. Part III focuses on engineering, ethics, and society, with chapters on engineering education and practice in China and the West. The book’s analyses of the interactions of science, engineering, ethics, politics, and policy in different societal contexts are of special interest. The volume as a whole marks a new stage in the emergence of the philosophy of engineering as a new regionalization of philosophy. This carefully edited interdisciplinary volume grew out of an international conference on the philosophy of engineering hosted by the University of the Chinese Academy of Sciences in Beijing. It includes 30 contributions by leading philosophers, social scientists, and engineers from Australia, China, Europe, and the United States. (shrink)
The New York Times receives more citations from academic journals than the American Sociological Review, Research Policy, or the Harvard Law Review. This article explores the reasons why scholars cite the NYT so much. Reasons include studying the newspaper itself or New York City, establishing public interest in a topic by referencing press coverage, introducing specificity, and treating the NYT very much like an academic journal. The phenomenon seems to reflect a mode 2 type of scholarship produced in the context (...) of application, organizationally diverse, socially accountable, and aiming to be socially useful as well as high quality as assessed by peers. (shrink)
With the rapid development of modern technology, people has stepped into an risky era. Ethical stipulation is the important means to reduce the risks. But in reality, ethical stipulation of technology always face some kind of dilemma which mainly come from two aspects: one is that when we try to regulate the subject oftechnology, we find that it always difficult to distinguish the responsibilities. The other aspect is that when we try to limit the result of technology, we often have (...) to give up because of lacking feasibility, which means we sink into the famous “Collingridge dilemma”. Are we able to get out of the dilemma? What should we doif we want to got out of it? First, in the modern technological system, individual’s action is taken over by group’s action according to the technological criterion. Any part of the modern technology need multiple subjects finish his job during the course. Therefore a new form of responsibility named group responsibility has been formed. Like Johnas said, in this ethics, ‘I’ will be replaced by ‘we’ and decision will be the business of a group. So it is difficult for us to find out that “I” from “us” once the technological risks happened. We lost the object of ethical stipulation as the result of no convinced standard and principals of prescribing the group responsibility. Second, when we try to stimulate some certain results of technology, we find we lack not only the wisdom of precisely judging or assessingtechnology itself, but also the ability of correcting the bad results if it has. Here again do we fall into the dilemma. This make it difficult for us to stipulate technology with ethic. From above discussion we can see, the stipulation, no matter from the aspect of technological responsibility or from aspect of the application of technology, has been sure to meet the dilemma. If the conflicts between a hypothesis and experiment cannot be eliminated, we have to rethink the theoryand come back again to technology itself and pursue the essence of technology again. Technology is a process from inventing, designing to forming material technological products; is a process from invisible technology to visible technology; is a process potential technology to real-life technology or intellective technology to reallife technology. Technology exists in process. The essential and innate characteristic is it’s process and dynamics. The transition oftechnological form involves many factors of economic, social, historical, constitutional and cultural. Technological creation of intellectual form is the duty of inventor or technologist. And it is entrepreneur’s job to use the technology or invention, and make them in large quantity, apply them in reality or get economic or other profit. Although there need be interaction, understanding, cooperation, support, coordination among scientist, technologist and enterpriser, they have different responsibility and delimitation. Technology exists in process, no doubt, so does modern technology. This decides that the ethical stipulation of modern technology should be a process stipulation . The essence of modern technological is not only the limitation of subject of technology either not only controlthe object of technology. It is the ethical stipulation in the unity of subject and object of technological dynamic process. This is basic point of understanding ethical stipulation of modern technology. Responsibility ethics consider that the group responsibility as the premise of technological stipulation .It noticed the static structure of modern technological system, but neglect the dynamic linkage between factors. And it only analysed the special construction, neglected the evolution of system of technological responsibility and the inter relationship between space dimension and time dimension. If we unfold the group responsibility along with the process of technology, we will see the different responsibility belong to different subject in different stage of the process. We can also see that different actors obey different norm or criteria according to their task. In this case, we can distinct the distribution of the group responsibility. Collingridge fixed the effective control on the two points of “before ”and ”after” the process of the technological action, namely, the stipulation for the staring point and stipulation of terminal point. But the whole process was neglected. According to the point of view of process stipulation .it is not the sudden occurrence for technology from “nothing ”to “having”. There are time and space during the process. From middle experiment to industrial experiment, the most characters of the result of technology will havebeen shown gradually, so will the social results. So we can give the small quantity an ethical evaluation and ethical choice which is possible and feasible. Over all, if we confirm the ethical stipulation of modern technology is a process regulation, we can delimitate the responsibility of the subjects of technology and also settle the prestipulation of the application of technology. At the end, we can eliminate the dilemma of ethical regulation of modern technology. (shrink)
Considering the current global trend in the digital economy, Facebook commerce is an indispensable component of today’s digital commerce. The purpose of this research is to test the proposed model to validate current theories that evaluate the relationships between online trust and customer f-commerce usage intentions. It has also been proposed to improve usage intention by integrating the relationship between perceived value and trust in electronic commerce. The data was gathered using a structured questionnaire and analyzed with structural equation modeling. (...) In this study, gender has been discussed as a moderating factor. The findings describe the positive relationships that exist between antecedents of trust and user intentions toward f-commerce. Furthermore, according to the findings of the study, females are more concerned than males about developing their intentions to utilize f-commerce for online shopping. Theoretical and practical implications are also presented in this study. (shrink)
Link prediction is a key tool for studying the structure and evolution mechanism of complex networks. Recommending new friend relationships through accurate link prediction is one of the important factors in the evolution, development, and popularization of social networks. At present, scholars have proposed many link prediction algorithms based on the similarity of local information and random walks. These algorithms help identify actual missing and false links in various networks. However, the prediction results significantly differ in networks with various structures, (...) and the prediction accuracy is low. This study proposes a method for improving the accuracy of link prediction. Before link prediction, k-shell decomposition method is used to layer the network, and the nodes that are in 1-shell and the nodes that are not linked to the high-shell in the 2-shell are deleted. The experiments on four real network datasets verify the effectiveness of the proposed method. (shrink)
Background: Work-related stress among healthcare professionals poses a serious economic and healthcare burden. This study aimed to investigate the prevalence of burnout as well as anxiety, depression, and stress in medical residents from different majors, and assess the effects of an online psychological intervention on the mental health status of medical residents with a high degree of burnout.Methods: We conducted an online survey that collected information on the demographics, mental health, and burnout conditions of medical residents from Shengjing Hospital. The (...) mental health condition was assessed by the Depression, Anxiety, and Stress Scale −21. Further, burnout was assessed by the Maslach Burnout Inventory. Medical residents with a total MBI score between 50 and 75 were selected to receive online psychological intervention for 3 months.Results: Two-hundred and ten medical residents completed the questionnaire, of whom, 63 residents with an MBI score between 50 and 75 received the 3-month online psychological intervention. Anesthesia residents showed the highest level of depression, anxiety, and stress, and presented with a lower sense of personal accomplishment, higher emotional exhaustion, and higher depersonalization. Furthermore, pediatric residents had the second highest DASS and MBI scores following anesthesia residents. Following the online psychological intervention, negative emotional states and burnout levels were significantly lower among anesthesia and pediatric residents. There were no differences in the level of stress and sense of personal accomplishment pre- and post-online psychological intervention among the different majors.Conclusion: Our findings revealed high levels of burnout, as well as depression, anxiety, and stress symptoms in medical residents, with marked differences among different majors. The online psychological intervention effectively improved emotional exhaustion, and depersonalization, and relieved the psychological problems such as anxiety and depression in medical residents. (shrink)
This paper considers a dual-channel supply chain with product customization. One manufacturer and one retailer are involved. The online direct sales channel sells standard and customized products, and the offline retail channel sells standard products. The prices and service levels of products sold via different channels are differentiated, and the customization level which influences the customization cost and choices of customers is decided by the manufacturer. Three game models are proposed: the manufacturer Stackelberg model, the retailer Stackelberg model, and the (...) Nash game model. The price and service decisions of the players are derived. Meanwhile, a service-cost-sharing contract is designed for the MS model. The impacts of price and service competition, service cost, and customers sensitivity to the customization level on the optimal decisions are investigated. Through the numerical analysis, we find that, among the three models, the manufacturer Stackelberg model is the most beneficial game structure for the overall supply chain but has the largest revenue gap between the two members. Second, under price competition and service competition, the manufacturer should differentiate the prices and services for direct sales standard products and customized products according to his market status. Third, the manufacturer should increase customization expenditures to construct his customization production line and provide more diversified products when consumers are more sensitive to product customization. (shrink)
Virus and information spreading dynamics widely exist in complex systems. However, systematic study still lacks for the interacting spreading dynamics between the two types of dynamics. This paper proposes a mathematical model on multiplex networks, which considers the heterogeneous susceptibility and infectivity in two subnetworks. By using a heterogeneous mean-field theory, we studied the dynamic process and outbreak threshold of the system. Through extensive numerical simulations on artificial networks, we find that the virus’s spreading dynamics can be suppressed by increasing (...) the information spreading probability, decreasing the protection power, or decreasing the susceptibility and infectivity. (shrink)
This book provides practical and research-based chapters that offer greater clarity about the particular kinds of teacher reflection that matter and avoids talking about teacher reflection generically, which implies that all kinds of reflection are of equal value.
Self-serving leadership is a form of unethical leadership behavior that has destructive effect on its targets and the overall organization. Adopting a social cognition perspective, this study expands our knowledge of its adverse effect and the way to mitigate the effect. Integrating two sub-theories of social cognition, we propose a theoretical model wherein self-serving leadership hinders team creativity through psychological safety as well as knowledge hiding, with task interdependence acting as a contextual condition. Results from a sample of 107 R&D (...) teams revealed that self-serving leadership not only reduced team psychological safety, but also induced team knowledge hiding, both of which ultimately affected team creativity. The presence of high task interdependence buffered the destructive effect of self-serving leadership on team creativity via team psychological safety as well as the indirect effect via knowledge hiding. (shrink)
Counterproductive work behavior is one of the most common behavioral decisions of employees in the workplace that negatively impacts the sustainable development of enterprises. Previous studies have shown that individuals make CWB decisions for different reasons. Some individuals engage in CWB due to cognitive factors, whereas others engage in CWB in response to leadership behaviors. The conservation of resources theory holds that individuals have the tendency to preserve, protect and acquire resources. When experiencing the loss of resources, individuals will show (...) irrational and aggressive behaviors in order to regain resources. When obtaining resources, individuals’ tension and pressure will be relieved. To maintain or continue obtaining resources, individuals will show more positive work attitudes and behaviors. Therefore, using the COR theory as the main theoretical framework, this study explores a serial mediation model between family supportive leadership and CWB through work-family conflict and moral disengagement, moderated by personal life attribution. A three-wave survey of 251 medical workers from three hospitals found that family supportive leadership can reduce employees’ perceived work-family conflict, which leads to less moral disengagement, resulting in lower CWB. Personal life attribution strengthens the negative indirect effect of family supportive leadership on CWB by reinforcing the negative association between family supportive leadership and work-family conflict. This study uses the COR theory to explore the mechanism and boundary conditions of family supportive leadership and CWB from the perspective of negative work-family relationship, which enrichis the research content of existing theories. Moreover, this study has important guiding significance for managers to take effective measures to reduce CWB. (shrink)
This paper deals with a single-machine resource allocation scheduling problem with learning effect and group technology. Under slack due-date assignment, our objective is to determine the optimal sequence of jobs and groups, optimal due-date assignment, and optimal resource allocation such that the weighted sum of earliness and tardiness penalties, common flow allowances, and resource consumption cost is minimized. For three special cases, it is proved that the problem can be solved in polynomial time. To solve the general case of problem, (...) the heuristic, tabu search, and branch-and-bound algorithms are proposed. (shrink)
The activity of synsedimentary faults plays an important role in controlling the distribution of sand bodies in basins and furthermore the porosity and permeability of reservoirs. We have used fault interpretation, the method of image and granularity size analysis, and the seismic pumping effect to investigate the control of the activity of the Kongdong fault on the development degree of the dissolution pores and grain size, further studying the controlling mechanism of the activity of synsedimentary faults on reservoir quality. The (...) results showed that the slip rate of synsedimentary faults is one of the main factors in controlling reservoir quality. The slip rate controls the accommodation space and hydrodynamic conditions and it furthermore controls the grain size. The higher the slip rate, the bigger the grain size in the downthrow wall of synsedimentary faults; the seismic pump produced by synsedimentary faults activity also controls the development degree of dissolution pores. The development degree of dissolution pores in the downthrown wall of synsedimentary faults is greater than that in the upthrown wall. Dissolution pores are more developed in areas with a large slip rate of synsedimentary faults. Porosity increases gradually with the increase of plane porosity of dissolution pores, whereas the changes of permeability are not obvious. (shrink)
ABSTRACT Academic dishonesty has remained high in Chinese college students. We examined Chinese college senior students’ everyday academic practices, especially academic dishonesty, considering the contextual changes inside and outside higher learning settings in China. Data were collected from 120 college seniors from four universities and were analyzed using a qualitative content-based exploratory approach in NVivo 10. Three themes were identified, including college seniors’ perceptions of academic dishonesty, contextual influences on academic dishonesty, and seniors’ personal attitudes about academic misconduct. Interview results (...) indicated that the contextual changes have reduced cheating both at the national level and at the college level; however, some contextual factors stubbornly remain unchanged, suggesting that the current, contextual climate on and beyond the Chinese college campuses should be restructured, not necessarily exclusively using top-down approaches. A theoretical model was provided to illustrate mechanisms associated with these students’ academic misconduct. Suggestions are discussed regarding future research and implications made for university personnel practice. (shrink)
The ethics-related beliefs of Chinese international graduate students are heavily influenced by their academic cultural background, and given the nature of that culture, they often face challenges when adapting to the U.S. academic environment. This qualitative study examines Chinese graduate students’ perceptions of the differences between Chinese and American academic integrity practices and the effects of those differences on their ethical practices and adaptations in a graduate program in the United States. Data were collected via semistructured interviews in a public (...) university in the United States. Findings suggest that perceptions of academic integrity in Chinese universities are influenced by Confucian philosophy, collectivist assumptions, and a resultant convenience mind-set. These cultural premises clash with academic expectations in the United States. Participants describe how they, and their Chinese peers, navigate U.S. integrity standards and provide recommendations for ways that U.S. schools can help them better adjust. We expand on those and provide recommendations for university personnel. (shrink)
Our previous study has shown impaired blood oxygen level-dependent /functional magnetic resonance imaging activation of the visual attention network in strabismic amblyopia. However, there has been no comparison of resting state fMRI activation and functional connectivity in brain regions of interest along the visual attention network including visual cortex, intraparietal sulcus, and frontal eye fields during closed eye resting across the SA, or anisometropic amblyopes groups. Hence, we compared, gray matter volume, amplitude of low frequency fluctuations, regional homogeneity, and FC (...) in the left and right hemisphere ROIs of the visual attention network in SA, AA, and healthy controls. Correlation analyses of corrected visual acuity of amblyopic eye and MRI results were also performed and showed that the LogMAR cVA of the amblyopic eye positively correlated with right zALFF and zReHo FEF of SA and right IPS of AA only. GMV of both left and right hemisphere V1 areas was significantly greater but ALFF was significantly lower for SA compared to AA and HC groups. zALFF and zReHo analyses in the AA and SA groups indicated significantly higher activation than that in the HC group in the right FEF and IPS but lower than that in the HC group in the left FEF, and only the SA group showed lower activation in both V1 areas than the HC group. FC values of the right FEF–left V1, right FEF–right V1, and right FEF–right IPS pathways in the SA and AA groups were also significantly higher than those in the HC group whereas all other FC values were non-significant. Thus, this study indicates that even during resting-state the visual attention network function is impaired in SA and AA participants with only right hemisphere FEF showing significant activation in SA and IPS in AA suggesting that the slower saccade activation times characteristic of amblyopic eyes lead to the dominant eye controlling activation of the visual attention network. (shrink)
BackgroundResearch has consistently shown the adverse effects of inappropriate parenting on adolescent depression. Meanwhile, interpersonal theories of depression suggest that depressed individuals elicit frustration and rejection from their relational partners.MethodUsing two-wave data from the Chinese Family Panel Studies, the present study examined the prospective relationships between parental care and adolescent depression. Participant were 426 adolescents born in 1999.ResultsResults from the structural equation model showed that parental care prospectively and negatively predicted depression among both adolescent boys and girls. Inversely, adolescent boys’ (...) depression, but not girls’ depression, negatively predicted subsequent parental care.ConclusionThe results suggest the interactive dynamic between parental care and adolescent depression as well as parents’ gendered responses to adolescent depression. (shrink)
Understanding the neural basis of schizophrenia (SZ) is important for shedding light on the neurobiological mechanisms underlying this mental disorder. Structural and functional alterations in the anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), hippocampus, and medial prefrontal cortex (MPFC) have been implicated in the neurobiology of SZ. However, the effective connectivity among them in SZ remains unclear. The current study investigated how neuronal pathways involving these regions were affected in first-episode SZ using functional magnetic resonance imaging (fMRI). Forty-nine patients (...) with a first-episode of psychosis and diagnosis of SZ—according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision—were studied. Fifty healthy controls (HCs) were included for comparison. All subjects underwent resting state fMRI. We used spectral dynamic causal modeling (DCM) to estimate directed connections among the bilateral ACC, DLPFC, hippocampus, and MPFC. We characterized the differences using Bayesian parameter averaging (BPA) in addition to classical inference (t-test). In addition to common effective connectivity in these two groups, HCs displayed widespread significant connections predominantly involved in ACC not detected in SZ patients, but SZ showed few connections. Based on BPA results, SZ patients exhibited anterior cingulate cortico-prefrontal-hippocampal hyperconnectivity, as well as ACC-related and hippocampal-dorsolateral prefrontal-medial prefrontal hypoconnectivity. In summary, spectral DCM revealed the pattern of effective connectivity involving ACC in patients with first-episode SZ. This study provides a potential link between SZ and dysfunction of ACC, creating an ideal situation to associate mechanisms behind SZ with aberrant connectivity among these cognition and emotion-related regions. (shrink)
The power load prediction is significant in a sustainable power system, which is the key to the energy system’s economic operation. An accurate prediction of the power load can provide a reliable decision for power system planning. However, it is challenging to predict the power load with a single model, especially for multistep prediction, because the time series load data have multiple periods. This paper presents a deep hybrid model with a serial two‐level decomposition structure. First, the power load data (...) are decomposed into components; then, the gated recurrent unit network, with the Bayesian optimization parameters, is used as the subpredictor for each component. Last, the predictions of different components are fused to achieve the final predictions. The power load data of American Electric Power were used to verify the proposed predictor. The results showed that the proposed prediction method could effectively improve the accuracy of power load prediction. (shrink)
Real-world multiobjective optimization problems are characterized by multiple types of decision variables. In this paper, we address weapon selection and planning problems, which include decision variables of weapon-type selection and weapon amount determination. Large solution space and discontinuous, nonconvex Pareto front increase the difficulty of problem solving. This paper solves the addressed problem by means of a multiobjective evolutionary algorithm based on decomposition. Two mechanisms are designed for the complex combinatorial characteristic of WSPPs. The first is that the neighborhood of (...) each individual is divided as selection and replacement neighborhoods. The second is that the neighborhood size is changing during the evolution by introducing a distance parameter to constrain the search scope of each subproblem. The proposed algorithm is termed as MOEA/D with distance-based divided neighborhoods which can overcome possible drawbacks of original MOEA/D with weighted sum approach for complex combinatorial problems. Benchmark instances are generated to verify the proposed approach. Experimental results suggest the effectiveness of the proposed algorithm. (shrink)
With the development of economy, the requirement of financial planning for individuals or families is emerging. In the era of the Internet, individual investors can conveniently enter the market and purchase financial products. Traditional portfolio management models focus on risky markets such as stock markets. However, risk-averse investors, such as normal families, may concern appropriate long-term financial planning. This paper considers the problem of portfolio management of bank financial products with a long-term planning horizon. By taking into account the final (...) return and the flexibility, a multiobjective model of long-term portfolio is proposed. A multiobjective evolutionary approach is employed for the handling of conflicting objectives. Test instances are generated to illustrate the problem. Experiment results show that the presented algorithm can efficiently find trade-off solutions. Our experimental results also show that crossover probabilities should be separately implemented for long-term portfolio problems with hybrid encoding. Performance comparison of different crossover operators suggest that, for a real-valued encoding part, the simulated binary crossover has a better performance than BLX- operator. While for a binary encoding part, a uniform crossover operator might be appropriate for large-scale instances. The proposed multiobjective model in this paper provides risk-averse investors with an appropriate decision support model for the long-term financial planning and management. (shrink)
In recent years, supply chain finance is exploited to solve the financing difficulties of small- and medium-sized enterprises. SME credit risk assessment is a critical part in the SCF system. The diffusion of SME credit risk may cause serious consequences, leading the whole supply chain finance system unstable and insecure. Compared with traditional credit risk assessment models, the supply chain relationship, credit condition of SME, and core enterprises should all be considered to rate SME credit risk in SCF. Traditional methods (...) mix all indicators from different index systems. They cannot give a quantitative result on how these index systems work. Furthermore, traditional credit risk assessment models are heavily dependent on the number of annotated SME data. However, it is implausible to accumulate enough credit risky SMEs in advance. In this paper, we propose an adaptive heterogenous multiview graph learning method to tackle the small sample size problem for SMEs’ credit risk forecasting. Three graphs are constructed by using indicators from supply chain operation, SME financial indicator, and nonfinancial indicator individually. All the graphs are integrated in an adaptive manner, providing a quantitative explanation on how the three parts cooperate. The experimental analysis shows that the proposed method has good performance for determining whether SME is risky or nonrisky in SCF. From the perspective of SCF, SME financing ability is still the main factor to determine the credit risk of SME. (shrink)
The N-Queens problem plays an important role in academic research and practical application. Heuristic algorithm is often used to solve variant 2 of the N-Queens problem. In the process of solving, evaluation of the candidate solution, namely, fitness function, often occupies the vast majority of running time and becomes the key to improve speed. In this paper, three parallel schemes based on CPU and four parallel schemes based on GPU are proposed, and a serial scheme is implemented at the baseline. (...) The experimental results show that, for a large-scale N-Queens problem, the coarse-grained GPU scheme achieved a maximum 307-fold speedup over a single-threaded CPU counterpart in evaluating a candidate solution. When the coarse-grained GPU scheme is applied to simulated annealing in solving N-Queens problem variant 2 with a problem size no more than 3000, the speedup is up to 9.3. (shrink)
The double-fed induction wind generator- based wind generation system contains power electronic converters and filter capacitor and inductor, which will bring about high-frequency harmonics under the influence of controllers. Aiming at this problem, this paper studies the relation between the output current and the harmonic source at grid-side and rotor-side converters based on their control features in the DFIG system. Furthermore, the harmonic equivalent models of these two converters are built, and the influence of different factors on harmonic features is (...) explored from four perspectives, i.e., modulation method, altering controller parameters, altering output power, and the unbalance of three-phase voltage. Finally, the effectiveness of the proposed model is verified through the 2 MW DFIG real-time hardware-in-the-loop test platform by StarSim software and real test data, respectively. (shrink)
Following the COVID-19 pandemic, online learning has become a new mode of learning that students must adapt to. However, the mechanisms by which students receive and grasp knowledge in the online learning mode remain unknown. Cognitive load theory offers instructions to students considering the knowledge of human cognition. Therefore, this study considers the CLT to explore the internal mechanism of learning under the online mode in an experimental study. We recruited 76 undergraduates and randomly assigned them to four groups in (...) which they will watch videos at four different kinds of speed. The study observed and analyzed how video playback speed affected students' learning and cognitive load to obtain the following results: Video playback speed significantly influenced the students' learning effect. The best effect was observed at the speed of 1.25× and 1.5×. The speed that affected the learning effect best differed according to the students' learning abilities. High-level group students performed best at the speed of 1.5×, whereas low-level group students performed best at the speed of 1.25×. The 1.5× speed showed significant differences in the learning effect by students' majors. This indicates that the cognitive load of liberal arts students increased greatly at this speed. A change in playback speed has a significant impact on the cognitive load. Accelerated playback speed increases the cognitive load of students. The highest learning effect is observed under medium cognitive load. (shrink)
This paper aims to disclose the compound topological and directional relationships of three simple regions in the three-dimensional space. For this purpose, the directional model and the 8-intersection model were coupled into an R5DOS-intersection model and used to represent three simple regions in the 3D space. The matrices represented by the model were found to be complete and mutually exclusive. Then, a self-designed algorithm was adopted to solve the model, yielding 11,038 achievable topological and directional relationships. Compared with the minimum (...) bounding rectangle model, the proposed model boasts strong expressive power. Finally, our model was applied to derive the topological and directional relationships between simple regions A and C from the known relationships between simple regions A and B and those between B and C. Based on the results, a compound relationship reasoning table was established for A and C. The research results shed new light on the representation and reasoning of 3D spatial relationships. (shrink)
In limestone-gypsum wet flue gas desulfurization process, the change process of pH value of slurry in absorption tower is a typical nonlinear system with time delay and various uncertainties, so it is difficult to establish an accurate mathematical model of slurry pH control process. According to the pH control process of the slurry of wet flue gas desulfurization process, a model-free adaptive control algorithm based on compact form dynamic linearization is designed to realize the tracking control of the pH value (...) of the slurry. Due to various interference factors in the pH control process of slurry in absorption tower, it is easy to cause jump change of control system parameters and even structure. Therefore, a model-free adaptive control algorithm based on switching strategy is proposed in this paper. According to different working conditions, several model-free adaptive controllers are established. The stability of the algorithm is analyzed for the two cases of fixed system parameters and jumping system parameters. It was found that the model-free adaptive controller based on the switching strategy can switch multiple controllers under the condition of system parameter jump, so as to realize the fast tracking control of the slurry pH value of the system absorption tower under different working conditions. Through this method, the overshoot can be reduced and the control quality can be improved. (shrink)