This paper presents an improved clustering algorithm for categorizing data with arbitrary shapes. Most of the conventional clustering approaches work only with round-shaped clusters. This task can be accomplished by quickly searching and finding clustering methods for density peaks, but in some cases, it is limited by density peaks and allocation strategy. To overcome these limitations, two improvements are proposed in this paper. To describe the clustering center more comprehensively, the definitions of local density and relative distance are fused with (...) multiple distances, including K-nearest neighbors and shared-nearest neighbors. A similarity-first search algorithm is designed to search the most matching cluster centers for noncenter points in a weighted KNN graph. Extensive comparison with several existing DPC methods, e.g., traditional DPC algorithm, density-based spatial clustering of applications with noise, affinity propagation, FKNN-DPC, and K-means methods, has been carried out. Experiments based on synthetic data and real data show that the proposed clustering algorithm can outperform DPC, DBSCAN, AP, and K-means in terms of the clustering accuracy, the adjusted mutual information, and the adjusted Rand index. (shrink)

The foundation scheme in set theory asserts that every nonempty class has an ∈\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\in $$\end{document}-minimal element. In this paper, we investigate the logical strength of the foundation principle in basic set theory and α\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha $$\end{document}-recursion theory. We take KP set theory without foundation as the base theory. We show that KP-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^-$$\end{document} + Π1\documentclass[12pt]{minimal} \usepackage{amsmath} (...) \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Pi _1$$\end{document}-Foundation + V=L\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V=L$$\end{document} is enough to carry out finite injury arguments in α\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha $$\end{document}-recursion theory, proving both the Friedberg-Muchnik theorem and the Sacks splitting theorem in this theory. In addition, we compare the strengths of some fragments of KP. (shrink)

The strap-down inertial navigation system is a commonly used sensor for autonomous underground navigation, which can be used for shearer positioning under a coal mine. During the process of initial alignment, inaccurate or time-varying noise covariance matrices will significantly degrade the accuracy of the initial alignment of the shearer. To overcome the performance degradation of the existing initial alignment algorithm under complex underground environment, a novel adaptive filtering algorithm is proposed by the integration of the strong tracking Kalman filter and (...) the sequential filter for the initial alignment of the shearer with complex underground environment. Compared with the traditional multiple fading factor strong tracking Kalman filter method, the proposed MSTSKF algorithm integrates the advantage of strong tracking Kalman filter and sequential filter, and multiple fading factor and forgetting factor for east and north velocity measurement are designed in the algorithm, respectively, which can effectively weaken the coupling relationship between the different states and increase strong robustness against process uncertainties. The simulation and experiment results show that the proposed MSTSKF method has better initial alignment accuracy and robustness than existing strong tracking Kalman filter algorithm. (shrink)

Two isolated Neogene carbonate platforms have developed in the rifted uplifts since the Early Miocene. A large-scale submarine canyon system, the Zhongjian Canyon, has developed in the tectonic depression between the two platforms since the Middle Miocene. High-resolution bathymetry data and 2D and 3D seismic data reveal the existence of the ZJC on the present seafloor, as well as in Neogene intervals. It exhibits typical characteristics of deepwater canyons that cut the surrounding rocks and indicate strong erosional features. The ZJC (...) resulted from northwest–southeast strike-slip fault activities during synrift and postrift stages, and it periodically grew during the development of carbonate platforms since the Middle Miocene. We identified four cycles of parallel to subparallel high amplitude and dim reflectors in seismic data, which we interpreted as alternating canyon fill, based on the interpretation of seismic facies. Thus, the sedimentary evolution of the ZJC can be divided into four typical stages, which were in the Middle Miocene, Late Miocene, Early Pliocene, and Pleistocene. Considering the tectonic background of the carbonate platforms, as well as the on-going igneous activities, the sediment filling the canyon could be derived from a mixture of carbonate clasts, igneous clasts, mud, and silt. The laminar high-amplitude reflectors and dim-reflector package represented a fining-upward sedimentary cycle. The coarse-grained sediment in canyon fillings could be turbidites, carbonate debrites, and even igneous clasts. In contrast, the fine-grained sediment is likely to be dominated by pelagic to hemipelagic mud, and silt. This case study describes a deepwater canyon under a carbonate-dominated sedimentary environment and has significant implications for improving our knowledge of periplatform slope depositional processes. Furthermore, the insight gained into periplatform slope depositional processes can be applied globally. (shrink)

Teacher support makes students feel loved and cared for because they believe that their teachers will provide them with opportunities to make choices, support them in independent problem solving, and understand their inner feelings. High TS levels reduce depression and anxiety, thereby improving students' mental well-being. This cross-sectional study involved 3,573 students from 29 schools in 16 counties/cities of six provinces, namely, Guizhou, Hubei, Jiangxi, Shanxi, Sichuan, and Yunnan. The aim was to examine the impact of TS on students' level (...) of depression. The results indicated that for children in elementary schools, their status as left-behind children played a moderating role between TS and depression. The level of depression in non-LBC children decreased significantly with increases in TS, but the reduction for LBC children was not significant. For children in middle/junior high schools, their LBC status did not play a moderating role between TS and depression. TS was negatively correlated with the children's level of depression, but there was a significant positive relationship between their LBC status and depression. The theoretical and practical significance of the research findings were further discussed. (shrink)

We give a survey of the study of nonstandard models in recursion theory and reverse mathematics. We discuss the key notions and techniques in effective computability in nonstandard models, and their applications to problems concerning combinatorial principles in subsystems of second order arithmetic. Particular attention is given to principles related to Ramsey’s Theorem for Pairs.

The point bar is one of the most important reservoirs in a meandering depositional system, and accurately building a 3D architecture model for point bars is crucial to predict hydrocarbon distribution within the reservoir. Unfortunately, we can only obtain a qualitative description about the internal architecture of the point bar due to the limited information or the low resolution of available data. To build a 3D prototype point bar reservoir model, we analyze the architecture of point bars by integrating high-resolution (...) ground penetrating radar data and modern deposition. We found that our GPR data have five main reflection patterns, and GPR facies can be used to relate with architectural elements. The concave-down GPR facies is usually related to the abandoned channel. The continuous, subhorizontal, subparallel GPR facies is commonly related with lateral-accretion sand bodies within the point bar. The multiple stacked small-scale, discontinuous reflections GPR facies is interpreted to be shale drapes within the point bar. We further analyzed the geometry parameters of the identified channels. We found that the nonsymmetric [Formula: see text] of abandoned channel near the channel axis is related to the ratio between the curvature of channel radius [Formula: see text] and channel width [Formula: see text]. Finally, we built two 3D channel reservoir models and our models could provide useful guidance for the architecture analysis of buried meandering fluvial reservoirs. (shrink)

A late Pleistocene delta exceeding [Formula: see text] offshore Hainan Island, northwestern South China Sea, is investigated using high-resolution seismic and core data to understand the relationship between subaqueous delta development and climate drivers during the Last Glacial Period. The seismic data indicate general progradational configurations toward the southwest or southeast, indicating that the sediments from the eastern slope offshore southwestern Hainan Island were transported southwestward and southeastward. The average thickness of the delta sediment is approximately 35 m, and it (...) has an arcuate shape surrounding the eastern slope. Therefore, the sediment provenances of the HNPD were mainly from the Red River drainage and Hainan Island. Comparison between the core dating results and the global sea-level curve indicates that the delta formed mainly during marine isotope stage 4. The topography of the basin, the sea-level change from low stand to high stand, and the southward oceanic currents driven by the glacial-period strong winter monsoon all contributed to the formation of the delta. Because the development of the delta required large riverine sediment input, we speculate that the main reason that the delta’s development ceased was the migration of the river channel along the eastern slope. Based on a comparison between the palaeobathymetric scenarios derived from published sea-level curves and the delta stratigraphy identified from the seismic profiles and cores, we have determined a possible range of relative sea level between 65 and 56 ka for the southwestern coast of Hainan Island, which might also be applicable for a broader region, i.e., the northern SCS. (shrink)

Social media users have increased rapidly in recent years; however, most are “silent users” who rarely share information online. To maintain social media companies’ stable operation and development, this research explored the effects of flow experience and identity formation on users’ intrinsic motivation to facilitate aggressive, spontaneous, and habitual participation in virtual communities. A total of 487 valid questionnaires were collected and underwent regression analysis. The results revealed that all three intrinsic motivations had a significant impact on social media participation, (...) with social interaction exerting the strongest influence. Flow experience and identification had significant, partial mediating effects on the relationship between motivation and participation. Several suggestions were provided based on the results to help social media enterprises increase user participation. It is hoped that this research could facilitate in transforming users into habitual participants to keep the operations of the virtual community stable and enduring. (shrink)

Emotions are now considered critical elements of a successful education. In English as a Foreign Language context, there are many challenges for teachers to deal with. Hence, it is necessary to take their emotions into consideration. Despite many studies in this area, researching teachers’ positive mood, hope, and academic buoyancy has been left less attended. Trying to introduce this line, the present study reviewed the definitions, related concepts, theories, and previous studies done on these three variables in detail. It also (...) touched upon the origins of researching emotion in educational contexts describing different schools of psychology. Additionally, the study offered some practical implications for EFL teachers, students, policy-makers, teacher trainers, and researchers. Finally, it enumerated the existing gaps in this area and made a number of research suggestions for future research. (shrink)

Deep learning and artificial intelligence are jointly applied to concrete piano teaching for children to comprehensively promote modern piano teaching and improve the overall teaching quality. First, the teaching environment and the functions of the intelligent piano are expounded. Then, a piano note onset detection method is proposed based on the convolution neural network. The network can analyze the time-frequency of the input piano music signal by transforming the original time-domain waveform of the piano music signal into the frequency distribution (...) varying with time. Besides, it can detect the note onset at a stable state after 8 × 104 iterations. Moreover, an intelligent piano teaching method is designed to teach Jingle Bells for 40 preschool children aged 4–6 years. Finally, a questionnaire survey is performed to investigate the teaching situation, including the learning interest and learning effect of children and learning feedback from parents. The results show that 80% of children like smart music scores, 82% of children like intelligent piano lessons with games, and 84% of children can learn actively in the intelligent piano class. Besides, 85% of parents believe that their children are more interested in learning piano. In general, the intelligent piano teaching method effectively combines DL with AI to realize the overall optimization of piano performance. It is widely favored by preschool children and their parents and plays an important role in improving the interest of preschool children in piano learning. (shrink)

With rapid changes in technology, knowledge innovation has become more and more complex. Complex partners facilitate knowledge creation and innovation in complex problem-solving. Relying on R&D cooperation with forerunners, latecomers can acquire new knowledge factors and new ideas and use them to create new knowledge. This study demonstrated the knowledge innovation mechanism based on linkages between periphery knowledge and core knowledge with knowledge map theory and set methodology. A case of R&D cooperation between latecomers and forerunners was introduced to verify (...) this mechanism. The results show that latecomers could share forerunners’ periphery knowledge in R&D cooperation through formal and informal interaction and acquire the core knowledge factors in periphery knowledge based on the linkages between them. With these core knowledge factors, latecomers integrate them into their internal knowledge system and create new knowledge. By analyzing the linkages between periphery and core knowledge factors, this study creatively demonstrates the knowledge innovation mechanism in knowledge linkage perspective. It deepens the understanding of R&D cooperation between latecomers and forerunners and expands the focus of knowledge innovation theory. This study provides a new insight into latecomers effectively activating internal and external knowledge resources through R&D cooperation. (shrink)

BackgroundPrehospital delay is associated with non-modifiable factors such as age, residential region, and disease severity. However, the impact of psychosocial factors especially for job burnout on prehospital decision delay is still little understood.MethodThis internet-based survey was conducted between 14 February 2021 and 5 March 2021 in China through the Wechat platform and web page. Self-designed questionnaires about the expected and actual length of prehospital decision time and the Chinese version of Maslach Burnout Inventory-General Survey, Type D Personality Scale-14, and Social (...) Support Rating Scale were applied. A total of 1,039 general participants with a history of perceptible but tolerable body discomfort were included.ResultsThe top six reasons for prehospital decision delay were: endure until self-healing, too busy to ask for leave, process for seeing a doctor too complicated, too tired after work, worry about the expenditure, and fear of being identified as with serious problem. The univariate analyses revealed that older age, type D personality, job burnout, and worrying about expenditure were associated with prolonged prehospital decision time, while engaged in medical-related job and with more social support would shorten the delay. The multivariate analysis using logistic regression model with forward selecting method showed that age [per 10 years, odds ratio 1.19, p 7 days). Mediating effects were analyzed by using bias-corrected percentile bootstrap methods. Social support was found partially mediated the relationship between the determinants and prehospital decision time. The partial mediating effect of social support accounted for 24.0% of the total effect for job burnout and 11.6% for worrying about expenditure.ConclusionPsychosocial factors have a non-negligible impact on prehospital decision delay. The crucial part of prehospital decision delay may be the lack of motivation inside. Job burnout and lack of social support, as two commonly seen features in the modern world, should be given enough consideration in disease prevention and treatment. (shrink)

Credit distribution is uneven in the domestic financial market since it is relatively easy for listed companies, mainly state-owned enterprises, to obtain banks’ funds. Unbalanced credit distribution has caused some listed companies to participate in “Borrow to Lend” activities. Based on the traditional “financing priority” theory and credit rationing theory, this paper studies the “Borrow to Lend” shadow banking activities of China’s non-financial listed companies based on the 2007–2018 financial statement data of Chinese-listed companies and discusses the micro-level and macro-level (...) related factors behind this activity. The empirical results show that China’s non-financial listed companies, especially the state-owned enterprises, are participating in obvious “Borrow to Lend” activities. The real economy’s rate of return shows a negative relationship with “Borrow to Lend” activities at the level of individual companies and their industries. This article uses the exogenous growth part of M2 growth to measure monetary policy tightness in terms of macro and credit policies. It uses the ratio of state-owned enterprise loans to total corporate loans as an approximate indicator of the credit distribution structure. The empirical results indicate that state-owned enterprises’ “Borrow to Lend” activities have shifted in the same direction as the tightening of monetary policy after the financial crisis. The proportion of state-owned enterprise loans positively correlates with state-owned enterprises’ “Borrow to Lend” activities. (shrink)

In this study, we examined the role of culture on early adolescents’ social reasoning about peer exclusion. A total of 80 U.S. and 149 Taiwanese early adolescents independently completed a social reasoning essay about peer exclusion. Analyses of the essays based on social-moral theories showed that U.S. students tended to reason about peer exclusion based on social conventional thinking whereas Taiwanese students were more attentive to personal and moral issues. Despite this difference, both groups of students referred to some common (...) social-moral concepts while reasoning about peer exclusion, including consideration of personal benefit, harming others’ welfare, personal concern, and punishment. The use of social reasoning strategies was similar across the two groups of students except that Taiwanese students relied more on judgment whereas U.S. students generated more alternative hypotheses. (shrink)

The South China Sea is one of the largest marginal seas in the Western Pacific region, and it has been widely accepted that the evolution of the basin and the development of its oceanic crusts is closely linked to seafloor spreading. A great controversy, however, is around whether or not there was a jump of mid-ocean ridges during seafloor spreading, particularly in the eastern South China Sea subbasin. A tectonostratigraphic interpretation using high-resolution seismic data demonstrated that: a southward jump event (...) of the mid-ocean ridge took place in the eastern subbasin during the seafloor spreading; the orientation of the mid-ocean ridge had dramatically changed after the event resulting in that the abandoned mid-ocean ridge is along an east–west direction, whereas the younger one is generally east–northeast/west–southwest oriented; the corresponding surface caused by the jump tectonic event and the pre-event sequence can be traced throughout the earlier formed oceanic crust; and paleo-magnetic data showed that the event occurred at approximately 25–23.8 Ma. The results of this study could be used to better understand the evolution and filling of the South China Sea and other associated marginal basins. (shrink)

According to the official discourse in China, the May 4 Movement of 1919 opened the process of modernization in Chinese history. In those years, Chinese intellectuals introduced some new concepts, such as democracy and science, to accelerate society’s development following this encounter with western modernization. At the same time, American philosopher John Dewey visited China, enabling more Chinese to know his ideas. The influence of Dewey’s visit to both himself and China has become a valuable research theme since then, especially (...) today, one century after his visit.In the past century, the pursuit of education in China has been much changed, both in practice and theory. It is time to consider: What would Dewey... (shrink)

Management ownership has ethical consequences because it has an interest alignment effect or an entrenchment effect. In this paper, we investigate the ethical consequences of management ownership in China using accounting conservatism as the direct measure of entrenchment and alignment between shareholders and managers. We argue and find that the ethical effect of management ownership differs significantly in firms with different ultimate controlling shareholders. Specifically, management ownership in non-state-owned enterprises has an alignment effect, while management ownership has less of an (...) alignment effect in state-owned enterprises than in NSOEs. These results show that the ethical consequences of management ownership are moderated by the nature of ultimate controlling ownership. (shrink)

The COVID-19 is creating panic among people around the world and is causing a huge public mental health crisis. Large numbers of observational studies focused on the prevalence of psychological problems during the COVID-19 pandemic were published. It is essential to conduct a meta-analysis of the prevalence of different psychological statuses to insight the psychological reactions of general population during the COVID-19 epidemic in China. Sixty six observational studies about the psychological statuses of people during the COVID-19 were included, searching (...) up to 1 December 2020. Strengthening the Reporting of Observational Studies in Epidemiology was used to evaluate the quality of the included studies. OpenMeta[Analyst] was used for the data analysis. High prevalence of acute stress and fear symptoms were observed in the early period of the epidemic. Additionally, anxiety and depression symptoms continued at a high prevalence rate during the epidemic. It should alert the lasting mental health problems and the risk of post-traumatic stress disorder and other mental disorders.Systematic Review Registration: PROSPERO CRD 42020171485. (shrink)

An integrated pest management prey-predator model with ratio-dependent and impulsive feedback control is investigated in this paper. Firstly, we determine the Poincaré map which is defined on the phase set and discuss its main properties including monotonicity, continuity, and discontinuity. Secondly, the existence and stability of the boundary order-one periodic solution are proved by the method of Poincaré map. According to the Poincaré map and related differential equation theory, the conditions of the existence and global stability of the order-one periodic (...) solution are obtained when ΦyA yA. Furthermore, we prove the existence of the order-kk≥2 periodic solution under certain conditions. Finally, we verify the main results by numerical simulation. (shrink)

Communication is rule governed; so are greetings which serve as a polite way of communication. The rules vary depending on the cultural context or the cultural context helps to define the rules and so communication rules are culturally diverse. It is important for foreign language learners to learn that communication rules are both culturally and contextually bound to achieve effective and efficient communication.

Virtual reality provides an immersive 360-degree viewing experience and has been widely used in many areas. However, the transmission of panoramic video usually places a large demand on bandwidth; thus, it is difficult to ensure a reliable quality of experience under a limited bandwidth. In this paper, we propose a field-of-view prediction methodology based on limited FoV feedback that can fuse the heat map and FoV information to generate a user view. The former is obtained through saliency detection, while the (...) latter is extracted from some user perspectives randomly, and it contains the FoV information of all users. Then, we design a QoE-driven panoramic video streaming system with a client/server architecture, in which the server performs rate adaptation based on the bandwidth and the predicted FoV. We then formulate it as a nonlinear integer programming problem and propose an optimal algorithm that combines the Karush–Kuhn–Tucker conditions with the branch-and-bound method to solve this problem. Finally, we evaluate our system in a simulation environment, and the results show that the system performs better than the baseline. (shrink)

This paper presents an active fault-tolerant method to mitigate sensor failures in multimotor synchronous control. First, inspired by the construction of the coupling matrix in complex network synchronous output, a consistent matrix is designed based on structural redundancy in synchronous control. This consistent matrix has two advantages: one is that it can reflect different sensor output similarities and the other one is that it can detect, locate, and estimate the sensor fault. Then, the fault information is integrated into the design (...) of tolerance control with an improved mean feedback mechanism. The proposed method is suitable for both single and multiple fault situations, and its effectiveness is finally verified by both MATLAB simulation and the ABB semiphysical experimental platform. (shrink)

Recently, it was demonstrated that multitasking evolutionary algorithm, a newly proposed algorithm, can solve multiple optimization problems simultaneously through a single run, breaking through the limitations of traditional evolutionary algorithms, with good convergence and exploration performance. As a novel algorithm, MTEA still has a lot of unexplored space. Generally speaking, the order of solution variables has no significant influence on the single-tasking EAs. To our knowledge, the effect of the order of variables in the multitasking scenario has not been explored. (...) To fill in this research gap, three orders of variables in the multitasking scenario are proposed in this paper, including full reverse order, bisection reverse order, and trisection reverse order. An important feature of these orders of variables is that an individual can recover as himself after two times of changing the order of variables. In order to verify our idea, these orders of variables are embedded into MTEA. The experiment results revealed that the effect of the different orders of variables is universal but not significant enough in the practical application. Furthermore, tasks with high similarity and high degree of intersection are sensitive to the order of variables and get great impact between tasks. (shrink)

The buried pipelines and metallic structures in subway systems are subjected to electrochemical corrosion under the stray current interference. The corrosion current density determines the degree and the speed of stray current corrosion. A method combining electrochemical experiment with the machine learning algorithm was utilized in this research to study the corrosion current density under the coupling action of stray current and chloride ion. In this study, a quantum particle swarm optimization-neural network model was built up to predict the corrosion (...) current density in the process of stray current corrosion. The QPSO algorithm was employed to optimize the updating process of weights and biases in the artificial neural network. The results show that the accuracy of the proposed QPSO-NN model is better than the model based on backpropagation neural network and particle swarm optimization-neural network. The accuracy distribution of the QPSO-NN model is more stable than that of the BPNN model and the PSO-NN model. The presented model can be used for the prediction of corrosion current density and provides the possibility to monitor the stray current corrosion in subway system through an intelligent learning algorithm. (shrink)

The vigorous development of the new energy automobile industry has highlighted the issue of efficient recycling of power batteries. Using a Stackelberg game, the pricing mechanism of dual-channel power battery recycling models under different government subsidies is investigated. Consequently, sensitivity analysis and comparison analysis are conducted, providing the pricing decision and the optimal profit of closed-loop supply chain systems. Finally, the effects of recycling efforts, power battery greenness levels, service levels, and consumer green recycling awareness on prices of power batteries (...) and profits are determined through numerical simulations, and the optimal prices under different strategies are compared. The results indicate that recycling prices of each party in the manufacturer subsidy model are relatively high, and consumers’ green awareness and the green levels of power batteries are directly proportional to the recycling prices offered by recycling parties. Automobile 4S stores and recycling networks should pay attention to the balance between the increase in the cost and the quantity of government subsidies for their recycling efforts. For recycling enterprises, maintaining an appropriate service level can maximize their profits and positively motivate the development of them. (shrink)

We give a survey of the study of nonstandard models in recursion theory and reverse mathematics. We discuss the key notions and techniques in effective computability in nonstandard models. and their applications to problems concerning combinatorial principles in subsystems of second order arithmetic. Particular attention is given to principles related to Ramsey's Theorem for Pairs.