Blasting in water-conveyance tunnels that cross rivers is vital for the safety and stability of embankments. In this work, a tunnel project that crosses the Yellow River in the north district of the first-phase Eastern Line of the South-to-North Water Diversion Project was selected as the research object. A complex modeling and numerical simulation on embankment stability with regard to the blasting power of the tunnel was conducted using the professional finite difference software FLAC3D to disclose the relationships between the (...) blasting seismic waves with vibration velocity and embankment displacement under different excavation steps. Calculation results demonstrated that displacement generally attenuated from the tunnel wall to the internal structure of rocks under the effect of blasting seismic waves. The tunnel wall was in tension, and tensile stress gradually transformed into compressive stress with increased depth into the rocks. The curtain-grouting zone was mainly concentrated in the compressive zones. For different excavation steps, the vibration velocity at different feature points was high at the beginning of blasting and then gradually decreased. The resultant displacement was relatively small in the early excavation period and slowly increased as blasting progressed. The effects of different excavation steps on the safety of surrounding rocks and embankment under blasting seismic waves were simulated. We found that the blasting-induced vibration velocity was within the safe range of the code and that the calculated displacement was within the allowed range. Numerical simulation was feasible to assess the safety and stability of engineering projects. (shrink)

The poor denoising effect for noisy grayscale images with traditional processing methods would be obtained under strong noise condition, and some image details would be lost. In this paper, a parallel array model of Fitzhugh–Nagumo neurons was proposed, which can restore noisy grayscale images well with low peak signal-to-noise ratio conditions and the image details are better preserved. Firstly, the row-column scanning method was used to convert the 2D grayscale image into a 1D signal, and then the 1D signal was (...) converted into a binary pulse amplitude modulation signal by signal modulation. The modulated signal was input to an FHN parallel array for stochastic resonance. Finally, the array output signal was restored to a 2D gray image, and the image restoration effect was analyzed based on the PSNR and Structural SIMilarity index. It is shown that the SR effect can be exhibited in an array of FHN neuron nonlinearities by increasing the array size, and the image restoration effect is significantly better than the traditional image restoration method, and larger PSNR and SSIM can be obtained. It provides a new idea for grayscale image restoration in a low PSNR environment. (shrink)

Previous studies have explored children’s intergroup resource allocation in the context of preexisting intergroup resource inequality. However, resource inequality between social groups often originates from different factors. This study explored the role of the origins of resource inequality on children’s intergroup resource allocations. In experiment 1, when there was no explicit origin of the intergroup inequality, children of different ages mainly allocated resources in an equal way and 5- to 6-year-olds showed ingroup bias. In experiment 2, we examined the influence (...) of different origins of intergroup inequality and found that 5- to 6-year-olds perpetuated intergroup inequality when resource inequality was based on either a structural or an internal factor. However, 10- to 11-year-olds rectified inequality or allocated equally when intergroup inequality was based on regional disparity and perpetuated resource inequality when intergroup inequality was based on performance difference. The origins of inequality appear to play an important role in children’s intergroup resource allocations, and older children can distinguish different origins of intergroup inequality in resource allocation. (shrink)

A fuzzy predictive fault-tolerant control scheme is proposed for a wide class of discrete-time nonlinear systems with uncertainties, interval time-varying delays, and partial actuator failures as well as unknown disturbances, in which the main opinions focus on the relevant theory of FPFTC based on Takagi-Sugeno fuzzy model description of these systems. The T-S fuzzy model represents the discrete-time nonlinear system in the form of the discrete uncertain time-varying delay state space, which is firstly constructed by a set of local linear (...) models and the nonlinear membership functions. The novel improved state space model can be further obtained by extending the output tracking error to the constructed model. Then the fuzzy predictive fault-tolerant control law based on this extended model is designed, which can increase more control degrees of freedom. Utilizing Lyapunov-Krasovskill theory, less conservative delay-range-dependent stable conditions in terms of linear matrix inequality constraints are given to ensure the asymptotically robust stability of closed-loop system. Meanwhile, the optimized cost function and H-infinity performance index are introduced to the stable conditions to guarantee the robust performance and antidisturbance capability. The simulation results on the temperature control of a strong nonlinear continuous stirred tank reactor show that the proposed control scheme is feasible and effective. (shrink)

This work investigates the finite-time control problem for a nonlinear four-tank cross-coupled liquid level system by the port-controlled Hamiltonian model. A fixed-free methodology is exhibited which can be used to simplify the controller design procedure. To get an adjustable convergent gain of the finite-time control, a feasible technique named damping normalization is proposed. A novel parameter autotuning algorithm is given to clarify the principle of choosing parameters of the PCH method. Furthermore, a finite-time controller is designed by a state-error desired (...) Hamiltonian function, and the relationship between the settling time and a parameter is given, which can be applied in practical engineering easily to adjust the settling time according to the industrial need. Finally, simulation and experimental results verify the effectiveness of the proposed algorithm. (shrink)

This study is aimed at investigating the relationship between perceived teacher support and learning engagement and exploring the mediation role played by technology acceptance and learning motivation. It adopted a structural equation modeling approach, with sampling 467 students from four middle schools in eastern China. The research findings showed that perceived teacher support is significantly associated with learning engagement. Learning motivation plays a mediating role in the relationship between perceived teacher support and learning engagement. There is the chain mediating effect (...) of technology acceptance and learning motivation on the relationship between perceived teacher support and learning engagement. All of these are of great importance for the teachers in the middle schools, as they help to increase students’ engagement with learning activities considering the background of the deep integration of information technology and education teaching. (shrink)

BackgroundWith the popularity of computers, the internet, and the global spread of COVID-19, more and more attention deficit hyperactivity disorder patients need timely interventions through the internet. At present, there are many online intervention schemes may help these patients. It is necessary to integrate data to analyze their effectiveness.ObjectivesOur purpose is to integrate the ADHD online interventions trials, study its treatment effect and analyze its feasibility, and provide reference information for doctors in other institutions to formulate better treatment plans.MethodsWe searched (...) PubMed, EMBASE and Cochrane libraries. We didn't limit the start date and end date of search results. Our last search was on December 1, 2021. The keyword is ADHD online therapy. We used the Cochrane bias risk tool to assess the quality of included studies, used the standardized mean difference as an effect scale indicator to measure data. Random effects model, subgroup analysis were used to analyze the data.ResultsSix randomized controlled trials were identified, including 261 patients with ADHD. These studies showed that online interventions was more effective than waiting list in improving attention deficit and social function of adults and children with ADHD. The attention deficit scores of subjects were calculated in six studies. The sample size of the test group was 123, the sample size of the control group was 133, and the combined SMD was −0.73. The social function scores of subjects were calculated in six studies. The sample size of the experimental group was 123 and the control group was 133. The combined SMD was −0.59.ConclusionsThe results show that online interventions of ADHD may be an effective intervention. In the future, we need more online intervention researches to improve the symptoms of different patients, especially for some patients who have difficulties in accepting face-to-face treatment. (shrink)

With the troubles of core losses and all-state confined to certain limitations which are the innate traits of permanent magnet synchronous motors, this article develops a command filtered adaptive backstepping approach to follow the track of PMSM’s desired rotor position. To begin with, the RBF neural network technique is utilized to get close to the uncharted nonlinear terms which existed in PMSM’s mathematical model. Meanwhile, an advanced adaptive command filter control methodology is constructed to avoid the computing explosion during the (...) process of backstepping design. Furthermore, to make sure that all the state variables are confined into certain ranges, we employed the barrier Lyapunov function at every step of the controllers construction. In addition, an error compensating mechanism is proposed to neutralize filtering errors and only one adaptive law is required. At last, simulation results bear out the superiority of the aforementioned control scheme. (shrink)

There are two frequent misunderstandings in the scholarship on modern China’s territorial transformation. First, the concept of lingtu 领土 is often seen as only developing after the 1911 Revolution, in opposition to the earlier concept of jiangyu diguo 疆域帝国. Second, jiangyu and lingtu are often confused and seen as basically the same concept at different historical stages. This essay takes the translation and dissemination of “territory” before the 1911 Revolution as a starting point to examine how the basic concept of (...) lingtu developed from a translated term to describe spatial relations into an important semantic resource of a political movement. On one hand, in the negotiations leading to the Treaty of Nerchinsk and in the modern treaty system, the translation of “territory” formed a new conceptual space, centred on lingtu, which differed from the idea of the “frontier”. The turn from jiangyu to lingtu was not a complete one; rather, part of the old concept was integrated into the new framework. On the other hand, the concept of lingtu also provided a semantic battlefield, and the battle was already opened before the revolution: the earlier ideas, diplomatic relations and national narrative already formed the basic concepts dominating discourses after the revolution. (shrink)

BackgroundSmartphone addiction has become a social problem that affects peoples’ quality of life and is frequently reported to be correlated with alexithymia, avoidant or anxious attachment styles, and subjective well-being. This study aimed to investigate the relationship between SA and alexithymia, attachment style, and subjective well-being.MethodsA meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The following electronic databases were searched: PubMed, Web of Science, Embase, PsycINFO, PsycArticles, China National Knowledge Infrastructure, WANFANG DATA, and Chongqing (...) VIP Information Co., Ltd.. Stata 16.0 was used to analyze the overall effect and test the moderating effect.ResultsOne hundred and ten studies were included, involving a total of 96,680 participants. SA had a significantly high positive correlation with alexithymia, attachment anxiety, and negative emotions, and a low positive correlation with attachment avoidance. In addition, there was a high negative correlation between SA and subjective well-being and a low negative correlation between SA, life satisfaction, and positive emotions. A moderation analysis revealed that age significantly moderated the relationship between SA and positive emotions. The tools for measuring SA significantly moderated the relationship between SA, alexithymia, attachment anxiety, and subjective well-being. Meanwhile, subjective well-being measurement tools significantly moderated the relationships between SA, subjective well-being, and negative emotions.ConclusionSA was closely related to alexithymia, attachment style, and subjective well-being. In the future, longitudinal research can be conducted to better investigate the dynamic changes in the relationship between them.Systematic review registration[www.crd.york.ac.uk/PROSPERO/], identifier [CRD42022334798]. (shrink)

To better reflect the precise clustering results of the data samples with different shapes and densities for affinity propagation clustering algorithm, an improved integrated clustering learning strategy based on three-stage affinity propagation algorithm with density peak optimization theory was proposed in this paper. DPKT-AP combined the ideology of integrated clustering with the AP algorithm, by introducing the density peak theory and k-means algorithm to carry on the three-stage clustering process. In the first stage, the clustering center point was selected by (...) density peak clustering. Because the clustering center was surrounded by the nearest neighbor point with lower local density and had a relatively large distance from other points with higher density, it could help the k-means algorithm in the second stage avoiding the local optimal situation. In the second stage, the k-means algorithm was used to cluster the data samples to form several relatively small spherical subgroups, and each of subgroups had a local density maximum point, which is called the center point of the subgroup. In the third stage, DPKT-AP used the AP algorithm to merge and cluster the spherical subgroups. Experiments on UCI data sets and synthetic data sets showed that DPKT-AP improved the clustering performance and accuracy for the algorithm. (shrink)

This study aimed to explore the association between the functioning of family environment and academic burnout of Chinese college students as well as the mediating effects of the interpersonal resource and intrapersonal resource [i.e., positive psychological capital ] in this relationship. A total of 1971 Chinese undergraduates were involved in an online questionnaire survey and data analysis. It was found that family cohesion and adaptability was negatively related to academic burnout. Mediation analyses demonstrated that family cohesion and adaptability did not (...) directly affect academic burnout, but indirectly through increasing PsyCap, and through enhancing peer support and then increasing PsyCap in serial. Meanwhile, the relationship between family cohesion and adaptability and academic burnout was not mediated by peer support alone. These findings highlight the family environment’s crucial role in youth mental health and positive development in the college context. (shrink)

During the 17th and 18th centuries, European investigations into Chinese geography underwent a process of change: firstly, from the wild imagination of the classical era to a natural perspective of modern trade, then historical interpretations of religious missionaries to the scientific mapping conducted by sovereign nation-states. This process not only prompted new production of maps, but also disseminated a large amount of geographical knowledge about China in massive publications. This has enriched the geographical vision of Chinese civilization while providing a (...) new intellectual framework for Europeans to understand China. Concurrently, it has formed another route for the travel of knowledge and intercultural interactions between the East and the West. Those interactions between space and knowledge have been reflected in the production, publication and dissemination of numerous maps of China in early modern Europe. (shrink)