The Daliangshan fault zone is the eastern branch in the central section of Xianshuihe-Xiaojiang fault system. It has been neglected for a long time, partly because of no destructive earthquake records along this fault...The Daliangshan fault zone is the eastern branch in the central section of Xianshuihe-Xiaojiang fault system. It has been neglected for a long time, partly because of no destructive earthquake records along this fault zone. On the other hand, it is located on the remote and inaccessible plateau. So far it was excluded as part of the Xianshuihe-Xiaojiang fault system. Based on the interpretation of aerophotographs and field investigations, we document this fault zone in detail, and give an estimation of strike-slip rate about 3 mm/a in Late Quaternary together with age dating data. The results suggest that the Daliangshan fault zone is a newly-generated fault zone resulted from shortcutting in the central section of Xianshuihe-Xiaojiang fault system because of the clockwise rotation of the Southeastern Tibetan Crustal Block, which is bounded by the Xianshuihe-Xiaojiang fault system. Moreover, the shortcutting may make the Daliangshan fault zone replace the Anninghe and Zemuhe fault zones gradually, and finally, the later two fault zones will probably die out with the continuous clockwise rotation.展开更多
In a centrifugal compressor, the leakage flow through the tip clearance generates the tip leakage vortex by the in- teraction with the main flow, and consequently makes the flow in the impeller passage more complex by...In a centrifugal compressor, the leakage flow through the tip clearance generates the tip leakage vortex by the in- teraction with the main flow, and consequently makes the flow in the impeller passage more complex by the inte- raction with the passage vortex. In addition, the tip leakage vortex interacts with the shock wave on the suction surface near the blade tip in the transonic centrifugal compressor impeller. Therefore, the detailed examination for the influence of the tip leakage vortex becomes seriously important to improve the aerodynamic performance cs- pccia｜ly for the transonic centrifugal compressor. In this study, the flows in the transonic centrifugal compressor with and without the tip clearance at the design condition were analyzed numerically by using the commercial CFD code. The computed results revealed that the tip leakage vortex induced by the high loading at the blade tip around the leading edge affected the loss generation by the reduction or the suppression of the shock wave on the suction surface of the blade.展开更多
In order to establish the design methodology of an ultra micro centrifugal compressor, which is the most important component of an ultra micro gas turbine unit, a 10 times size of the final target compressor （impelle...In order to establish the design methodology of an ultra micro centrifugal compressor, which is the most important component of an ultra micro gas turbine unit, a 10 times size of the final target compressor （impeller outer diameter 40 mm, corrected rotational speed 220,000 r/min） was designed. The problems to be solved for downsizing were examined and a 2-dimensional impeller was chosen as the first model due to its productivity. The conventional 1D prediction method and CFD were used. The prototyped compressor was tested by using cold air at the reduced speed of 110,000 r/min. Following to the 10 times model, a 5 times size of the final target model having fully 3-dimensional shape （impeller outer diameter 20mm, corrected rotational speed 500,000 r/min） was designed and tested by using hot gas at the reduced speed of 250,000 r/min.展开更多
Since the 1950s,when the Turing Test was introduced,there has been notable progress in machine language intelligence.Language modeling,crucial for AI development,has evolved from statistical to neural models over the ...Since the 1950s,when the Turing Test was introduced,there has been notable progress in machine language intelligence.Language modeling,crucial for AI development,has evolved from statistical to neural models over the last two decades.Recently,transformer-based Pre-trained Language Models(PLM)have excelled in Natural Language Processing(NLP)tasks by leveraging large-scale training corpora.Increasing the scale of these models enhances performance significantly,introducing abilities like context learning that smaller models lack.The advancement in Large Language Models,exemplified by the development of ChatGPT,has made significant impacts both academically and industrially,capturing widespread societal interest.This survey provides an overview of the development and prospects from Large Language Models(LLM)to Large Multimodal Models(LMM).It first discusses the contributions and technological advancements of LLMs in the field of natural language processing,especially in text generation and language understanding.Then,it turns to the discussion of LMMs,which integrates various data modalities such as text,images,and sound,demonstrating advanced capabilities in understanding and generating cross-modal content,paving new pathways for the adaptability and flexibility of AI systems.Finally,the survey highlights the prospects of LMMs in terms of technological development and application potential,while also pointing out challenges in data integration,cross-modal understanding accuracy,providing a comprehensive perspective on the latest developments in this field.展开更多
Complex optimization problems hold broad significance across numerous fields and applications.However,as the dimensionality of such problems increases,issues like the curse of dimensionality and local optima trapping ...Complex optimization problems hold broad significance across numerous fields and applications.However,as the dimensionality of such problems increases,issues like the curse of dimensionality and local optima trapping also arise.To address these challenges,this paper proposes a novel Wild Gibbon Optimization Algorithm(WGOA)based on an analysis of wild gibbon population behavior.WGOAcomprises two strategies:community search and community competition.The community search strategy facilitates information exchange between two gibbon families,generating multiple candidate solutions to enhance algorithm diversity.Meanwhile,the community competition strategy reselects leaders for the population after each iteration,thus enhancing algorithm precision.To assess the algorithm’s performance,CEC2017 and CEC2022 are chosen as test functions.In the CEC2017 test suite,WGOA secures first place in 10 functions.In the CEC2022 benchmark functions,WGOA obtained the first rank in 5 functions.The ultimate experimental findings demonstrate that theWildGibbonOptimization Algorithm outperforms others in tested functions.This underscores the strong robustness and stability of the gibbonalgorithm in tackling complex single-objective optimization problems.展开更多
Friction is a phenomenon observed ubiquitously in daily life,yet its nature is complicated.Friction between rough surfaces is considered to arise primarily because of macroscopic roughness.In contrast,interatomic forc...Friction is a phenomenon observed ubiquitously in daily life,yet its nature is complicated.Friction between rough surfaces is considered to arise primarily because of macroscopic roughness.In contrast,interatomic forces dominate between clean and smooth surfaces.“Superlubricity”,where friction effectively becomes zero,occurs when the ratio of lattice parameters in the pair of surfaces becomes an irrational number.Superlubricity has been found to exist in a limited number of systems,but is a very important phenomenon both in industry and in mechanical engineering.New atomistic research on friction is under way,with the aim of refining theoretical models that consider interactions between atoms beyond mean field theory and experiments using ultrahigh vacuum non-contact atomic force microscopy.Such research is expected to help clarify the nature of microscopic friction,reveal the onset conditions of friction and superlubricity as well as the stability of superlubricity,discover new superlubric systems,and lead to new applications.展开更多
This paper investigates the causal relationship between the Urban and Rural Resident Basic Medical Insurance(URRBMI)reform and household consumption in urban China using data from the Chinese Household Income Project ...This paper investigates the causal relationship between the Urban and Rural Resident Basic Medical Insurance(URRBMI)reform and household consumption in urban China using data from the Chinese Household Income Project survey and employing combination of the propensity score matching and difference-in-differences methods.The results yield three conclusions.First,the reform affected both the amount and share of household consumption.Specifically,the reform led to an increase in total household consumption,encompassing both medical and nonmedical expenditures.Among these,the proportion of medical consumption increased,while the proportion of nonmedical consumption reduced.Second,the impact of the URRBMI reform varied across consumption categories within nonmedical expenditure.Specifically,consumption for education and entertainment industries are positively impacted by the URRBMI reform in terms of both quantity and proportion.Third,low-income households benefit more from the URRBMI reform compared to middle-and high-income households.The main channels through which the URRBMI reform affects household consumption were the price effect and the crowding out effect on precautionary savings.展开更多
In order to establish the design methodology of ultra micro centrifugal compressor,wich is the most important component of ultra micro gas turbine unit,a 10 times of the final target size model was designed,prototyped...In order to establish the design methodology of ultra micro centrifugal compressor,wich is the most important component of ultra micro gas turbine unit,a 10 times of the final target size model was designed,prototyped and tested.The problems to be solved for downsizing were examined and 2-dimensional impeller was chosen as the first model due to its productivity.The conventional 1D prediction method.CFD and the inverse design were attempted.The prototyped compressor was driven by using a turbocharger and the performance characteristics were measured.展开更多
The crowd sensing technology can realize the sensing and computing of people,machines,and environment in smart industrial IoT-based coal mine,which provides a solution for safety monitoring through distributed intelli...The crowd sensing technology can realize the sensing and computing of people,machines,and environment in smart industrial IoT-based coal mine,which provides a solution for safety monitoring through distributed intelligence optimization.However,due to the difficulty of neural network training to achieve global optimality and the fact that traditional LSTM methods do not consider the relationship between adjacent machines,the accuracy of human body position prediction and pressure value prediction is not high.To solve these problems,this paper proposes a smart industrial IoT empowered crowd sensing for safety monitoring in coal mine.First,we propose a Particle Swarm Optimization-Elman Neural Network(PE)algorithm for the mobile human position prediction.Second,we propose an ADI-LSTM neural network prediction algorithm for pressure values of machines supports in underground mines.Among them,our proposed PE algorithm has the lowest average cumulative prediction error,and the trajectory fit rate is improved by 24.1%,13.9%and 8.7%compared with Kalman filtering,Elman and Kalman plus Elman algorithms,respectively.Meanwhile,compared with single-input ARIMA,RNN,LSTM,and GRU,the RMSE values of our proposed ADI-LSTM are reduced by 36.6%,52%,32%,and 13.7%,respectively;and the MAPE values are reduced by 0.0003%,0.9482%,1.1844%,and 0.3620%,respectively.展开更多
Interactive Recommendation(IR)formulates the recommendation as a multi-step decision-making process which can actively utilize the individuals’feedback in multiple steps and optimize the long-term user benefit of rec...Interactive Recommendation(IR)formulates the recommendation as a multi-step decision-making process which can actively utilize the individuals’feedback in multiple steps and optimize the long-term user benefit of recommendation.Deep Reinforcement Learning(DRL)has witnessed great application in IR for ecommerce.However,user cold-start problem impairs the learning process of the DRL-based recommendation scheme.Moreover,most existing DRL-based recommendations ignore user relationships or only consider the single-hop social relationships,which cannot fully utilize the social network.The fact that those schemes can not capture the multiple-hop social relationships among users in IR will result in a sub-optimal recommendation.To address the above issues,this paper proposes a Social Graph Neural network-based interactive Recommendation scheme(SGNR),which is a multiple-hop social relationships enhanced DRL framework.Within this framework,the multiple-hop social relationships among users are extracted from the social network via the graph neural network which can sufficiently take advantage of the social network to provide more personalized recommendations and effectively alleviate the user cold-start problem.The experimental results on two real-world datasets demonstrate that the proposed SGNR outperforms other state-of-the-art DRL-based methods that fail to consider social relationships or only consider single-hop social relationships.展开更多
Considering that modern mobile terminals possess the capability to detect users' proximity,and offer means to directly communicate and share content with the people in close area,Device-to-Device(D2D) based Proxim...Considering that modern mobile terminals possess the capability to detect users' proximity,and offer means to directly communicate and share content with the people in close area,Device-to-Device(D2D) based Proximity Services(ProSe) have recently witnessed great development,which enable users to seek for and utilize relevant value in their physical proximity,and are capable to create numerous new mobile service opportunities.However,without a breakthrough in battery technology,the energy will be the biggest limitation for ProSe.Through incorporating the features of ProSe(D2D communication technologies,abundant built-in sensors,localization-dependent,and context-aware,etc.),this paper thoroughly investigates the energy-efficient architecture and technologies for ProSe from the following four aspects:underlying networking technology,localization,application and architecture features,context-aware and user interactions.Besides exploring specific energy-efficient schemes pertaining to each aspect,this paper offers a perspective for research and applications.In brief,through classifying,summarizing and optimizing the multiple efforts on studying,modeling and reducing energy consumption for ProSe on mobile devices,the paper would provide guide for developers to build energy-efficient ProSe.展开更多
Purpose: Fertility education for high school students leads them to be able to decide when to get pregnant and give birth, and to think about their desired life plan. However, knowledge of fertility in Japan is low co...Purpose: Fertility education for high school students leads them to be able to decide when to get pregnant and give birth, and to think about their desired life plan. However, knowledge of fertility in Japan is low compared to other countries. This study aims to understand the state of fertility knowledge among high school students in Japan and to clarify issues in fertility education. Method: Ten articles published from 2013 to July 2023 were selected for review from ICHUSHI Web Ver. 5 and CiNii with the keywords “high school students,” “fertility,” and “education.” The review was limited to Japanese-language literature due to differences in fertility education and knowledge between Japan and other countries. Results/Conclusion: 60% - 90% of the high school students indicated that their source of information on fertility was school lessons. Half of the students understood egg aging and the effects of smoking and drinking on fertility, but their knowledge of menstruation, male reproductive physiology/function, and infertility was insufficient. 50% - 80% of students wanted to marry by the age of 30, and 70% - 80% wanted to have children. 80% of students who attended a lecture on preconception care considered the lesson an opportunity to think about their future life plans. 90% of school nurse teachers reported that fertility should be taught in schools, and half said that egg aging, causes of infertility, and other topics should be covered in high school. Educational caution points included the consideration of developmental stages and the relatedness of the content to what had already been taught, among other things. High school is the best time for fertility education because it gives students the opportunity to accept their own sexuality and think about their future. In addition, since many students plan to marry and have children by the age of 30, the acquisition of fertility knowledge can be an effective means of future life design.展开更多
The secondary flow within a passage of turbomachinery exhibits a complex flow pattern by the effect of the centrifugal and the Coriolis forces. The passage vortex in this secondary flow generates a major part of the l...The secondary flow within a passage of turbomachinery exhibits a complex flow pattern by the effect of the centrifugal and the Coriolis forces. The passage vortex in this secondary flow generates a major part of the losses. However, the mechanism of the loss generation has not been fully clarified yet. In this point of view, the passage vortex is closely examined by the computational method using the two-dimensional curved square ducts as fundamental models. The inlet boundary layer thickness and the inlet velocity distortion are considered to be the major parameters affecting the generation of passage vortex in the present study. The computed results revealed that the passage vortex gave the predominant effects for the generation of loss not only in the breakdown process but also in the development process.展开更多
Contour detection has a rich history in multiplefields such as geography,engineering,and earth science.The predominant approach is based on piecewise planar tessellation and now being challenged concerning the extract...Contour detection has a rich history in multiplefields such as geography,engineering,and earth science.The predominant approach is based on piecewise planar tessellation and now being challenged concerning the extraction of contour objects for non-linear elevation functions,particularly with respect to bicubic spline functions.A storage-efficient method was developed in previous research,but the detection of the complete set of contour objects is yet to be realized.Although intractable,theoretical underpinnings pertinent to curvature resulted in an approach to realize the complete detection of objects.Given a digital elevation model dataset,in this study,a bicubic spline surface function wasfirst determined.Thereafter,candidate initial points on the edges across the region of interest were identified,and the recursive disaggregation of rectangles was repeated if the non-existence of a solution could not be assured.A developed tracking method was then applied.During advancement,other initial points on the same contour curve were identified and eliminated to circumvent duplicate detection.The completeness of the outlets provides analytical tools for elevation and other geographical assessments.Demonstrative experiments included the development of a three-dimensional contour-based network and slope assessments.The latter application transforms the slope analysis type from raster-based to vector-based.Highlights.Detection of a complete set of contour objects amenable to bicubic spline surfaces..Small closure inside a single patch is detectable if size exceeds the standard..Curvature&tolerances central to step length adjustment and tangent angle determination..Redundant initial points are identified and eliminated during the tracking process..Various potential applications in addition to geographical elevations.展开更多
Recently, many channelized rivers tend to be heavily vegetated due to regime shifts in hydrological, fluvial and ecological processes. Dense vegetation in a river frequently obstructs a flood flow and reduces conveyan...Recently, many channelized rivers tend to be heavily vegetated due to regime shifts in hydrological, fluvial and ecological processes. Dense vegetation in a river frequently obstructs a flood flow and reduces conveyance capacity of channels. On the other hand, river vegetation provides various ecological services such as habitats for various species and life, natural cycle of organic and inorganic substances, etc.. It is of engineering importance to understand vegetation hydrodynamics in order to preserve vegetation nature and keep a certain level of flow conveyance capacity. In view that willows tend to be densely vegetated along the shoreline of floodplains or sandbars, a field measurement, a physical model experiment and a numerical analysis were carried out for investigating hydrodynamics in an open channel with riparian vegetation. Discussion was made focusing on flow and shear layer structures developed around the vegetation canopy.展开更多
I consider a system whose deterioration follows a discrete-time and discrete-state Markov chain with an absorbing state. When the system is put into practice, I may select operation (wait), imperfect repair, or replac...I consider a system whose deterioration follows a discrete-time and discrete-state Markov chain with an absorbing state. When the system is put into practice, I may select operation (wait), imperfect repair, or replacement at each discrete-time point. The true state of the system is not known when it is operated. Instead, the system is monitored after operation and some incomplete information concerned with the deterioration is obtained for decision making. Since there are multiple imperfect repairs, I can select one option from them when the imperfect repair is preferable to operation and replacement. To express this situation, I propose a POMDP model and theoretically investigate the structure of an optimal maintenance policy minimizing a total expected discounted cost for an unbounded horizon. Then two stochastic orders are used for the analysis of our problem.展开更多
In the operation of a centrifugal compressor of turbocharger, instability phenomena such as rotating stall and surge are induced at a lower flow rate close to the maximum pressure ratio. In this study, the compressed ...In the operation of a centrifugal compressor of turbocharger, instability phenomena such as rotating stall and surge are induced at a lower flow rate close to the maximum pressure ratio. In this study, the compressed air at the exit of centrifugal compressor was re-circulated and injected to the impeller inlet by using two injection nozzles in order to suppress the surge phenomenon. The most effective circumferential position was examined to reduce the flow rate at the surge inception. Moreover, the influences of the injection on the fluctuating property of the flow field before and after the surge inception were investigated by examining the frequency of static pressure fluctuation on the wall surface and visualizing the compressor wall surface by oil-film visualization technique.展开更多
This paper reports the experimental and theoretical study of the surge occurred in prototyping an ultra micro centrifugal compressor. As the first step, the 10 times size model of an ultra micro centrifugal compressor...This paper reports the experimental and theoretical study of the surge occurred in prototyping an ultra micro centrifugal compressor. As the first step, the 10 times size model of an ultra micro centrifugal compressor having the 40 mm outer diameter was designed and manufactured. The detailed experimental investigations for the transient behavior of surge with several different values of B parameter were carded out. The experimental results during the surge were compared with those obtained by the non-linear lumped parameter theory in order to validate the effectiveness of the theoretical surge model for the micro centrifugal compressor. As a result, the quite different behavior of the surge appeared for the different values of B both in the experiment and in the analysis.展开更多
One of the major challenges in the field of motors is to improve rotation ripples. There are several causes of rotation ripples. This paper focuses on variations of manufacturing of a stator coil and proposes a new te...One of the major challenges in the field of motors is to improve rotation ripples. There are several causes of rotation ripples. This paper focuses on variations of manufacturing of a stator coil and proposes a new technique called DTMM （dynamic multi-coils-motor three-phase matching） based on the conventional NSDEM （noise shaping dynamic element matching）. With DTMM, all the moving elements are shuffled while a single moving element is shuffled with NSDEM. Results show that the proposed system reduces the rotation ripple by 30% compared to the conventional PWM driving technology.展开更多
In the operation of a centrifugal compressor of turbocharger, instability phenomena such as rotating stall and surge are induced at a lower flow rate close to the maximum pressure ratio. In this study, for the suppres...In the operation of a centrifugal compressor of turbocharger, instability phenomena such as rotating stall and surge are induced at a lower flow rate close to the maximum pressure ratio. In this study, for the suppression of surge phenomenon resulting in the extension of the stable operating range of centrifugal compressor to lower flow rate, the compressed air at the compressor exit was re-circulated and injected into the impeller inlet by using the double injection nozzle system. The experiments were performed to find out the optimum circumferential position of the second nozzle relative to the fixed first one and the optimum inner diameter of the injection nozzles, which are able to most effectively reduce the flow rate of surge inception. Moreover, in order to examine the universality of these optimum values, the experiments were carried out for two types of compressors.展开更多
基金the National Basic Research Program of China (Grant No. 2004CB418401)the National Natural Science Foundation of China (Grant No. 40472109)+1 种基金Joint Earthquake Science Foundation of China (Grant No. 105066)Japan Grant-in Aid for Scientific Research from Japan Ministry of Education, Cul-ture, Sports, Science and Technology (Grant No. 18500776)
文摘The Daliangshan fault zone is the eastern branch in the central section of Xianshuihe-Xiaojiang fault system. It has been neglected for a long time, partly because of no destructive earthquake records along this fault zone. On the other hand, it is located on the remote and inaccessible plateau. So far it was excluded as part of the Xianshuihe-Xiaojiang fault system. Based on the interpretation of aerophotographs and field investigations, we document this fault zone in detail, and give an estimation of strike-slip rate about 3 mm/a in Late Quaternary together with age dating data. The results suggest that the Daliangshan fault zone is a newly-generated fault zone resulted from shortcutting in the central section of Xianshuihe-Xiaojiang fault system because of the clockwise rotation of the Southeastern Tibetan Crustal Block, which is bounded by the Xianshuihe-Xiaojiang fault system. Moreover, the shortcutting may make the Daliangshan fault zone replace the Anninghe and Zemuhe fault zones gradually, and finally, the later two fault zones will probably die out with the continuous clockwise rotation.
文摘In a centrifugal compressor, the leakage flow through the tip clearance generates the tip leakage vortex by the in- teraction with the main flow, and consequently makes the flow in the impeller passage more complex by the inte- raction with the passage vortex. In addition, the tip leakage vortex interacts with the shock wave on the suction surface near the blade tip in the transonic centrifugal compressor impeller. Therefore, the detailed examination for the influence of the tip leakage vortex becomes seriously important to improve the aerodynamic performance cs- pccia｜ly for the transonic centrifugal compressor. In this study, the flows in the transonic centrifugal compressor with and without the tip clearance at the design condition were analyzed numerically by using the commercial CFD code. The computed results revealed that the tip leakage vortex induced by the high loading at the blade tip around the leading edge affected the loss generation by the reduction or the suppression of the shock wave on the suction surface of the blade.
文摘In order to establish the design methodology of an ultra micro centrifugal compressor, which is the most important component of an ultra micro gas turbine unit, a 10 times size of the final target compressor （impeller outer diameter 40 mm, corrected rotational speed 220,000 r/min） was designed. The problems to be solved for downsizing were examined and a 2-dimensional impeller was chosen as the first model due to its productivity. The conventional 1D prediction method and CFD were used. The prototyped compressor was tested by using cold air at the reduced speed of 110,000 r/min. Following to the 10 times model, a 5 times size of the final target model having fully 3-dimensional shape （impeller outer diameter 20mm, corrected rotational speed 500,000 r/min） was designed and tested by using hot gas at the reduced speed of 250,000 r/min.
基金We acknowledge funding from NSFC Grant 62306283.
文摘Since the 1950s,when the Turing Test was introduced,there has been notable progress in machine language intelligence.Language modeling,crucial for AI development,has evolved from statistical to neural models over the last two decades.Recently,transformer-based Pre-trained Language Models(PLM)have excelled in Natural Language Processing(NLP)tasks by leveraging large-scale training corpora.Increasing the scale of these models enhances performance significantly,introducing abilities like context learning that smaller models lack.The advancement in Large Language Models,exemplified by the development of ChatGPT,has made significant impacts both academically and industrially,capturing widespread societal interest.This survey provides an overview of the development and prospects from Large Language Models(LLM)to Large Multimodal Models(LMM).It first discusses the contributions and technological advancements of LLMs in the field of natural language processing,especially in text generation and language understanding.Then,it turns to the discussion of LMMs,which integrates various data modalities such as text,images,and sound,demonstrating advanced capabilities in understanding and generating cross-modal content,paving new pathways for the adaptability and flexibility of AI systems.Finally,the survey highlights the prospects of LMMs in terms of technological development and application potential,while also pointing out challenges in data integration,cross-modal understanding accuracy,providing a comprehensive perspective on the latest developments in this field.
基金funded by Natural Science Foundation of Hubei Province Grant Numbers 2023AFB003,2023AFB004Education Department Scientific Research Program Project of Hubei Province of China Grant Number Q20222208+2 种基金Natural Science Foundation of Hubei Province of China(No.2022CFB076)Artificial Intelligence Innovation Project of Wuhan Science and Technology Bureau(No.2023010402040016)JSPS KAKENHI Grant Number JP22K12185.
文摘Complex optimization problems hold broad significance across numerous fields and applications.However,as the dimensionality of such problems increases,issues like the curse of dimensionality and local optima trapping also arise.To address these challenges,this paper proposes a novel Wild Gibbon Optimization Algorithm(WGOA)based on an analysis of wild gibbon population behavior.WGOAcomprises two strategies:community search and community competition.The community search strategy facilitates information exchange between two gibbon families,generating multiple candidate solutions to enhance algorithm diversity.Meanwhile,the community competition strategy reselects leaders for the population after each iteration,thus enhancing algorithm precision.To assess the algorithm’s performance,CEC2017 and CEC2022 are chosen as test functions.In the CEC2017 test suite,WGOA secures first place in 10 functions.In the CEC2022 benchmark functions,WGOA obtained the first rank in 5 functions.The ultimate experimental findings demonstrate that theWildGibbonOptimization Algorithm outperforms others in tested functions.This underscores the strong robustness and stability of the gibbonalgorithm in tackling complex single-objective optimization problems.
文摘Friction is a phenomenon observed ubiquitously in daily life,yet its nature is complicated.Friction between rough surfaces is considered to arise primarily because of macroscopic roughness.In contrast,interatomic forces dominate between clean and smooth surfaces.“Superlubricity”,where friction effectively becomes zero,occurs when the ratio of lattice parameters in the pair of surfaces becomes an irrational number.Superlubricity has been found to exist in a limited number of systems,but is a very important phenomenon both in industry and in mechanical engineering.New atomistic research on friction is under way,with the aim of refining theoretical models that consider interactions between atoms beyond mean field theory and experiments using ultrahigh vacuum non-contact atomic force microscopy.Such research is expected to help clarify the nature of microscopic friction,reveal the onset conditions of friction and superlubricity as well as the stability of superlubricity,discover new superlubric systems,and lead to new applications.
基金the National Social Science Foundation of China(No.19ZDA116)the Japan Society for the Promotion of Science(No.20H01512)the Fundamental Research Funds for the Central Universities.
文摘This paper investigates the causal relationship between the Urban and Rural Resident Basic Medical Insurance(URRBMI)reform and household consumption in urban China using data from the Chinese Household Income Project survey and employing combination of the propensity score matching and difference-in-differences methods.The results yield three conclusions.First,the reform affected both the amount and share of household consumption.Specifically,the reform led to an increase in total household consumption,encompassing both medical and nonmedical expenditures.Among these,the proportion of medical consumption increased,while the proportion of nonmedical consumption reduced.Second,the impact of the URRBMI reform varied across consumption categories within nonmedical expenditure.Specifically,consumption for education and entertainment industries are positively impacted by the URRBMI reform in terms of both quantity and proportion.Third,low-income households benefit more from the URRBMI reform compared to middle-and high-income households.The main channels through which the URRBMI reform affects household consumption were the price effect and the crowding out effect on precautionary savings.
文摘In order to establish the design methodology of ultra micro centrifugal compressor,wich is the most important component of ultra micro gas turbine unit,a 10 times of the final target size model was designed,prototyped and tested.The problems to be solved for downsizing were examined and 2-dimensional impeller was chosen as the first model due to its productivity.The conventional 1D prediction method.CFD and the inverse design were attempted.The prototyped compressor was driven by using a turbocharger and the performance characteristics were measured.
基金supported in part by the National Natural Science Foundation of China(Grant No.61902311),in part by the Postdoctoral Research Foundation of China(Grant No.2019M663801)in part by the Scientific Research Project of Shaanxi Provincial Education Department(Grant No.22JK0459)+1 种基金Key R&D Foundation of Shaanxi Province(Grant No.2021SF-479)in part by the Japan Society for the Promotion of Science(JSPS)Grants-in-Aid for Scientific Research(KAKENHI)under Grant JP18K18044 and JP21K17736.
文摘The crowd sensing technology can realize the sensing and computing of people,machines,and environment in smart industrial IoT-based coal mine,which provides a solution for safety monitoring through distributed intelligence optimization.However,due to the difficulty of neural network training to achieve global optimality and the fact that traditional LSTM methods do not consider the relationship between adjacent machines,the accuracy of human body position prediction and pressure value prediction is not high.To solve these problems,this paper proposes a smart industrial IoT empowered crowd sensing for safety monitoring in coal mine.First,we propose a Particle Swarm Optimization-Elman Neural Network(PE)algorithm for the mobile human position prediction.Second,we propose an ADI-LSTM neural network prediction algorithm for pressure values of machines supports in underground mines.Among them,our proposed PE algorithm has the lowest average cumulative prediction error,and the trajectory fit rate is improved by 24.1%,13.9%and 8.7%compared with Kalman filtering,Elman and Kalman plus Elman algorithms,respectively.Meanwhile,compared with single-input ARIMA,RNN,LSTM,and GRU,the RMSE values of our proposed ADI-LSTM are reduced by 36.6%,52%,32%,and 13.7%,respectively;and the MAPE values are reduced by 0.0003%,0.9482%,1.1844%,and 0.3620%,respectively.
文摘Interactive Recommendation(IR)formulates the recommendation as a multi-step decision-making process which can actively utilize the individuals’feedback in multiple steps and optimize the long-term user benefit of recommendation.Deep Reinforcement Learning(DRL)has witnessed great application in IR for ecommerce.However,user cold-start problem impairs the learning process of the DRL-based recommendation scheme.Moreover,most existing DRL-based recommendations ignore user relationships or only consider the single-hop social relationships,which cannot fully utilize the social network.The fact that those schemes can not capture the multiple-hop social relationships among users in IR will result in a sub-optimal recommendation.To address the above issues,this paper proposes a Social Graph Neural network-based interactive Recommendation scheme(SGNR),which is a multiple-hop social relationships enhanced DRL framework.Within this framework,the multiple-hop social relationships among users are extracted from the social network via the graph neural network which can sufficiently take advantage of the social network to provide more personalized recommendations and effectively alleviate the user cold-start problem.The experimental results on two real-world datasets demonstrate that the proposed SGNR outperforms other state-of-the-art DRL-based methods that fail to consider social relationships or only consider single-hop social relationships.
基金supported by the National Natural Science Foundation of China under Grant 61171092the JiangSu Educational Bureau Project under Grant 14KJA510004Prospective Research Project on Future Networks(JiangSu Future Networks Innovation Institute)
文摘Considering that modern mobile terminals possess the capability to detect users' proximity,and offer means to directly communicate and share content with the people in close area,Device-to-Device(D2D) based Proximity Services(ProSe) have recently witnessed great development,which enable users to seek for and utilize relevant value in their physical proximity,and are capable to create numerous new mobile service opportunities.However,without a breakthrough in battery technology,the energy will be the biggest limitation for ProSe.Through incorporating the features of ProSe(D2D communication technologies,abundant built-in sensors,localization-dependent,and context-aware,etc.),this paper thoroughly investigates the energy-efficient architecture and technologies for ProSe from the following four aspects:underlying networking technology,localization,application and architecture features,context-aware and user interactions.Besides exploring specific energy-efficient schemes pertaining to each aspect,this paper offers a perspective for research and applications.In brief,through classifying,summarizing and optimizing the multiple efforts on studying,modeling and reducing energy consumption for ProSe on mobile devices,the paper would provide guide for developers to build energy-efficient ProSe.
文摘Purpose: Fertility education for high school students leads them to be able to decide when to get pregnant and give birth, and to think about their desired life plan. However, knowledge of fertility in Japan is low compared to other countries. This study aims to understand the state of fertility knowledge among high school students in Japan and to clarify issues in fertility education. Method: Ten articles published from 2013 to July 2023 were selected for review from ICHUSHI Web Ver. 5 and CiNii with the keywords “high school students,” “fertility,” and “education.” The review was limited to Japanese-language literature due to differences in fertility education and knowledge between Japan and other countries. Results/Conclusion: 60% - 90% of the high school students indicated that their source of information on fertility was school lessons. Half of the students understood egg aging and the effects of smoking and drinking on fertility, but their knowledge of menstruation, male reproductive physiology/function, and infertility was insufficient. 50% - 80% of students wanted to marry by the age of 30, and 70% - 80% wanted to have children. 80% of students who attended a lecture on preconception care considered the lesson an opportunity to think about their future life plans. 90% of school nurse teachers reported that fertility should be taught in schools, and half said that egg aging, causes of infertility, and other topics should be covered in high school. Educational caution points included the consideration of developmental stages and the relatedness of the content to what had already been taught, among other things. High school is the best time for fertility education because it gives students the opportunity to accept their own sexuality and think about their future. In addition, since many students plan to marry and have children by the age of 30, the acquisition of fertility knowledge can be an effective means of future life design.
文摘The secondary flow within a passage of turbomachinery exhibits a complex flow pattern by the effect of the centrifugal and the Coriolis forces. The passage vortex in this secondary flow generates a major part of the losses. However, the mechanism of the loss generation has not been fully clarified yet. In this point of view, the passage vortex is closely examined by the computational method using the two-dimensional curved square ducts as fundamental models. The inlet boundary layer thickness and the inlet velocity distortion are considered to be the major parameters affecting the generation of passage vortex in the present study. The computed results revealed that the passage vortex gave the predominant effects for the generation of loss not only in the breakdown process but also in the development process.
基金supported by Japan Society for the Promotion of Science[grant number 21 K01021].
文摘Contour detection has a rich history in multiplefields such as geography,engineering,and earth science.The predominant approach is based on piecewise planar tessellation and now being challenged concerning the extraction of contour objects for non-linear elevation functions,particularly with respect to bicubic spline functions.A storage-efficient method was developed in previous research,but the detection of the complete set of contour objects is yet to be realized.Although intractable,theoretical underpinnings pertinent to curvature resulted in an approach to realize the complete detection of objects.Given a digital elevation model dataset,in this study,a bicubic spline surface function wasfirst determined.Thereafter,candidate initial points on the edges across the region of interest were identified,and the recursive disaggregation of rectangles was repeated if the non-existence of a solution could not be assured.A developed tracking method was then applied.During advancement,other initial points on the same contour curve were identified and eliminated to circumvent duplicate detection.The completeness of the outlets provides analytical tools for elevation and other geographical assessments.Demonstrative experiments included the development of a three-dimensional contour-based network and slope assessments.The latter application transforms the slope analysis type from raster-based to vector-based.Highlights.Detection of a complete set of contour objects amenable to bicubic spline surfaces..Small closure inside a single patch is detectable if size exceeds the standard..Curvature&tolerances central to step length adjustment and tangent angle determination..Redundant initial points are identified and eliminated during the tracking process..Various potential applications in addition to geographical elevations.
基金supported by the Himeji River Road Management Office, the Ministry of Land, Infrastructure, Transport and Tourismthe Grant-in-Aid for Scientific Research (B)(Grant No. 23360212, Leader: Kohji Michioku).
文摘Recently, many channelized rivers tend to be heavily vegetated due to regime shifts in hydrological, fluvial and ecological processes. Dense vegetation in a river frequently obstructs a flood flow and reduces conveyance capacity of channels. On the other hand, river vegetation provides various ecological services such as habitats for various species and life, natural cycle of organic and inorganic substances, etc.. It is of engineering importance to understand vegetation hydrodynamics in order to preserve vegetation nature and keep a certain level of flow conveyance capacity. In view that willows tend to be densely vegetated along the shoreline of floodplains or sandbars, a field measurement, a physical model experiment and a numerical analysis were carried out for investigating hydrodynamics in an open channel with riparian vegetation. Discussion was made focusing on flow and shear layer structures developed around the vegetation canopy.
文摘I consider a system whose deterioration follows a discrete-time and discrete-state Markov chain with an absorbing state. When the system is put into practice, I may select operation (wait), imperfect repair, or replacement at each discrete-time point. The true state of the system is not known when it is operated. Instead, the system is monitored after operation and some incomplete information concerned with the deterioration is obtained for decision making. Since there are multiple imperfect repairs, I can select one option from them when the imperfect repair is preferable to operation and replacement. To express this situation, I propose a POMDP model and theoretically investigate the structure of an optimal maintenance policy minimizing a total expected discounted cost for an unbounded horizon. Then two stochastic orders are used for the analysis of our problem.
文摘In the operation of a centrifugal compressor of turbocharger, instability phenomena such as rotating stall and surge are induced at a lower flow rate close to the maximum pressure ratio. In this study, the compressed air at the exit of centrifugal compressor was re-circulated and injected to the impeller inlet by using two injection nozzles in order to suppress the surge phenomenon. The most effective circumferential position was examined to reduce the flow rate at the surge inception. Moreover, the influences of the injection on the fluctuating property of the flow field before and after the surge inception were investigated by examining the frequency of static pressure fluctuation on the wall surface and visualizing the compressor wall surface by oil-film visualization technique.
文摘This paper reports the experimental and theoretical study of the surge occurred in prototyping an ultra micro centrifugal compressor. As the first step, the 10 times size model of an ultra micro centrifugal compressor having the 40 mm outer diameter was designed and manufactured. The detailed experimental investigations for the transient behavior of surge with several different values of B parameter were carded out. The experimental results during the surge were compared with those obtained by the non-linear lumped parameter theory in order to validate the effectiveness of the theoretical surge model for the micro centrifugal compressor. As a result, the quite different behavior of the surge appeared for the different values of B both in the experiment and in the analysis.
文摘One of the major challenges in the field of motors is to improve rotation ripples. There are several causes of rotation ripples. This paper focuses on variations of manufacturing of a stator coil and proposes a new technique called DTMM （dynamic multi-coils-motor three-phase matching） based on the conventional NSDEM （noise shaping dynamic element matching）. With DTMM, all the moving elements are shuffled while a single moving element is shuffled with NSDEM. Results show that the proposed system reduces the rotation ripple by 30% compared to the conventional PWM driving technology.
文摘In the operation of a centrifugal compressor of turbocharger, instability phenomena such as rotating stall and surge are induced at a lower flow rate close to the maximum pressure ratio. In this study, for the suppression of surge phenomenon resulting in the extension of the stable operating range of centrifugal compressor to lower flow rate, the compressed air at the compressor exit was re-circulated and injected into the impeller inlet by using the double injection nozzle system. The experiments were performed to find out the optimum circumferential position of the second nozzle relative to the fixed first one and the optimum inner diameter of the injection nozzles, which are able to most effectively reduce the flow rate of surge inception. Moreover, in order to examine the universality of these optimum values, the experiments were carried out for two types of compressors.
