This paper focuses on the direct and inverse problems for a third-order self-adjoint differential operator with non-local potential and anti-periodic boundary conditions.Firstly,we obtain the expressions for the chara...This paper focuses on the direct and inverse problems for a third-order self-adjoint differential operator with non-local potential and anti-periodic boundary conditions.Firstly,we obtain the expressions for the characteristic function and resolvent of this third-order differential operator.Secondly,by using the expression for the resolvent of the operator,we prove that the spectrum for this operator consists of simple eigenvalues and a finite number of eigenvalues with multiplicity 2.Finally,we solve the inverse problem for this operator,which states that the non-local potential function can be reconstructed from four spectra.Specially,we prove the Ambarzumyan theorem and indicate that odd or even potential functions can be reconstructed by three spectra.展开更多
The method in [1] has been extended to the case of rotational flow in this paper. A new method for dealing with the shock wave is presented. This method has the advantages of both the shock-fitting and the shock captu...The method in [1] has been extended to the case of rotational flow in this paper. A new method for dealing with the shock wave is presented. This method has the advantages of both the shock-fitting and the shock capturing methods. The direct problem and the mixed direct-inverse prob- lem of the rotational flow in a transonic plane cascade at both design and off design conditions are solved, and the results show that the present method has rapid convergence rate and high accuracy even for the flow with moderately strong shocks. The calculations have been carried out on the DPS-8 computer, and for the direct problem, only 50-80 iterations are needed, and 50-80 seconds of CPU time are required.展开更多
Introduction: Orthopaedic surgery includes varieties of injuries and other pathologies. Treatments are complicated while healing and recovery take time. Rehabilitation needs planning and commitment. In the Chinese Com...Introduction: Orthopaedic surgery includes varieties of injuries and other pathologies. Treatments are complicated while healing and recovery take time. Rehabilitation needs planning and commitment. In the Chinese Communities, traditional medicine has been popular since hundreds of years ago and has remained so in spite of the current advances in medicine. The purpose of this review is to identify the techniques being used in current situations, the indications and problems. Varieties of Traditional Treatments: 1) Topical applications of herbs are very much welcome after joint sprains, inflammatory conditions and even fractures. 2) On the wide area of physical training, the Chinese Tai-chi and Qigong are excellent gentle exercises for personal pursues. These exercises emphasize on body-mind interactions and carry strong philosophical insights. 3) Acupuncture has become standard rehabilitation practice in some hospitals and is getting even more popular in pain control and rehabilitation training after nerve injuries. Problems: Topical agents for pain and inflammation are not totally safe because allergic adverse conditions could happen from time to time. The major concern could be the unawareness of non-unions or delayed unions in fracture cases after herbal applications because the traditional healers are using too little modern assessment tools. Physical trainings and acupunctures are on the whole safe, only that indications are not clearly defined. Future Direction: 1) Concerning the topical agents used for pain and swelling, the essential research requirements include demonstration on the topical agents’ anti inflammatory, angiogenic and cell regenerative effects. The capability of skin penetration needs to be confirmed and a final clinical trial will further confirm the efficacy. 2) Clinical researches trying to obtain evidence on the use of Tai-chi and Qigong on the neuromuscular recovery are plentiful, while their effects on cardiovascular and respiratory health are likewise encouraging. 3) Acupuncture has already become a standard treatment option for pain control, nausea/vomiting and neuromuscular recoveries.展开更多
We present a direct algorithm for solving the vertical generalized linear complementarity problem, first considered by Cottle and Dantzig, when the associated matrix is a vertical block P-matrix. The algorithm converg...We present a direct algorithm for solving the vertical generalized linear complementarity problem, first considered by Cottle and Dantzig, when the associated matrix is a vertical block P-matrix. The algorithm converges to a unique solution in a finite number of steps, without an assumption of nondegeneracy on the given problem. The algorithm is simple, efficient, and easy to implement.展开更多
Objective: To explore the effects of self-directed learning readiness and learning attitude on problem-solving ability among Chinese undergraduate nursing students. Methods: A convenience sampling of 460 undergraduate...Objective: To explore the effects of self-directed learning readiness and learning attitude on problem-solving ability among Chinese undergraduate nursing students. Methods: A convenience sampling of 460 undergraduate nursing students was surveyed in Tianjin, China. Students who participated in the study completed a questionnaire that included social demographic questionnaire, Self-directed Learning Readiness Scale, Attitude to Learning Scale, and Social Problem-Solving Inventory. Pearson’s correlation analysis was performed to test the correlations among problem-solving ability, self-directed learning readiness, and learning attitude. Hierarchical linear regression analyses were performed to explore the mediating role of learning attitude. Results: The results showed that learning attitude (r=0.338, P<0.01) and self-directed learning readiness (r=0.493, P<0.01) were positively correlated with problem-solving ability. Learning attitude played a partial intermediary role between self-directed learning readiness and problem-solving ability (F=74.227, P<0.01). Conclusions: It is concluded that nursing educators should pay attention on students’ individual differences and take proper actions to inspire students’ self-directed learning readiness and learning attitude.展开更多
Boundary Element Method (BEM) is widely used in electrocardiographic (ECG) problem. Formulations of these problems based on mathematical and numerical approximations of the known source in heart and the volume conduct...Boundary Element Method (BEM) is widely used in electrocardiographic (ECG) problem. Formulations of these problems based on mathematical and numerical approximations of the known source in heart and the volume conductor that can transfer voltages on the surface of the body. To analyze the electric potentials on body surface or epicardial surface, a set of discrete equations derived from a boundary integral equations need to be solved. Solving these equations means to get the potential distribution eventually. In the process of solving, transfer matrix of discrete equations has received considerable attention, how to get an appropriate transfer matrix is an important issue. This paper found that the direction of normal vector could affect the results when calculating the transfer matrix and presents a method analogous to Mesh Current Method to deal with this direction problem. Several simulations have been carried out to verify the accurate results with the correct direction of normal vector using new method within a torso model given simultaneous epicardial and body surface potential recordings.展开更多
An inverse estimation method and corresponding measurement system are developed to measure the apparent spectral directional emissivities of semitransparent materials. The normal spectral emissivity and transmissivity...An inverse estimation method and corresponding measurement system are developed to measure the apparent spectral directional emissivities of semitransparent materials. The normal spectral emissivity and transmissivity serve as input for the inverse analysis. Consequently, the refractive index and absorption coefficient of the semitransparent material could be retrieved by using the pseudo source adding method as the forward method and the stochastic particle swarm optimization algorithm as the inverse method. Finally, the arbitrary apparent spectral directional emissivity of semitransparent material is estimated by using the pseudo source adding method given the retrieval refractive index and absorption coefficient. The present system has the advantage of a simple experimental structure, high accuracy, and excellent capability to measure the emissivity in an arbitrary direction. Furthermore, the apparent spectral directional emissivity of sapphire at 773 K is measured by using this system in a spectral range of 3 μm-12 μm and a viewing range of 0°-90°. The present method paves the way for a new directional spectral emissivity measurement strategy.展开更多
Urban agglomerations are an inevitable outcome of China＇s new national industrialization and urbanization reaching relatively advanced stages of development over the past 30 years. In the early 2000 s, urban agglomer...Urban agglomerations are an inevitable outcome of China＇s new national industrialization and urbanization reaching relatively advanced stages of development over the past 30 years. In the early 2000 s, urban agglomerations became new geographical units for participating in global competition and the international division of labor, and China has spent the past decade promoting them as the main spaces for pushing forward its new form of urbanization. The convening of the first Central Work Conference on Urbanization and the National New-type Urbanization Plan（2014–2020） further defined the status of urban agglomerations as the main players in promoting China＇s new type of national urbanization. Nevertheless, urban agglomerations remain a weak link in Chinese academia and are in urgent need of study. Only 19 articles on the theme of urban agglomerations were published in the journal Acta Geographica Sinica between 1934 and 2013, accounting for only 0.55% of all articles written during that period. Not only are there very few, they have also all been published within a relatively short period of time, with the first having been published only 10 years ago. The studies are also concentrated among only a few authors and institutions, and research is aimed at national requirements but is rather divergent. Even so, some studies on urban agglomerations have played a leading role and made important contributions to dictating the overall formation of urban agglomerations nationwide. Specifically, a proposed spatial pattern for urban agglomerations formed the basic framework for the spatial structure of China＇s urban agglomerations and guided the government to make urban agglomerations the main urban pattern when promoting the new type of urbanization; proposed standards and technologies for identifying the spatial dimensions of urban agglomerations played an important role in defining the scope of national urban agglomerations; a series of studies in the area of urban agglomerations spurred more in-depth and practical studies in the field; and studies on issues related to the formation and growth of urban agglomerations provided warnings on the future selection and development of urban agglomerations. Taking the progress and results of these studies as a foundation, the foci of selecting and developing urban agglomerations in China are as follows： to be problem-oriented and profoundly reflect on and review new problems exposed in the selection and development of urban agglomerations; to concentrate on urban agglomerations and lay importance on the formation of a new “5＋9＋6” spatial structure for China＇s urban agglomerations; to rely on urban agglomerations and promote the formation of a new pattern of national urbanization along the main axes highlighted by urban agglom-erations; to be guided by national strategic demand and continue to deepen understanding of major scientific issues in the course of the formation and development of urban agglomerations, including studying the resource and environmental effects of high-density urban agglomerations, scientifically examining resource and environmental carrying capacities of high-density urban agglomerations, creating new management systems and government coordination mechanisms for the formation and development of urban agglomerations, studying the establishment of public finance systems and public finance reserve mechanisms for urban agglomerations, and studying and formulating technical specifications for urban agglomeration planning and standards for delineating urban agglomeration boundaries.展开更多
We present a direct analytical algorithm for solving transportation problems with quadratic function cost coefficients. The algorithm uses the concept of absolute points developed by the authors in earlier works. The ...We present a direct analytical algorithm for solving transportation problems with quadratic function cost coefficients. The algorithm uses the concept of absolute points developed by the authors in earlier works. The versatility of the proposed algorithm is evidenced by the fact that quadratic functions are often used as approximations for other functions, as in, for example, regression analysis. As compared with the earlier international methods for quadratic transportation problem (QTP) which are based on the Lagrangian relaxation approach, the proposed algorithm helps to understand the structure of the QTP better and can guide in managerial decisions. We present a numerical example to illustrate the application of the proposed method.展开更多
As far as the weighted digraph is considered, an optimal directed spanning tree algorithm called table based algorithm (TBA) is proposed in the paper based on the table instead of the weighted digraph. The optimality ...As far as the weighted digraph is considered, an optimal directed spanning tree algorithm called table based algorithm (TBA) is proposed in the paper based on the table instead of the weighted digraph. The optimality is proved, and a numerical example is demonstrated.展开更多
For the linear least squares problem with coefficient matrix columns being highly correlated, we develop a greedy randomized Gauss-Seidel method with oblique direction. Then the corresponding convergence result is ded...For the linear least squares problem with coefficient matrix columns being highly correlated, we develop a greedy randomized Gauss-Seidel method with oblique direction. Then the corresponding convergence result is deduced. Numerical examples demonstrate that our proposed method is superior to the greedy randomized Gauss-Seidel method and the randomized Gauss-Seidel method with oblique direction.展开更多
Petroleum science has made remarkable progress in organic geochcmistry and in the research into the theories of petroleum origin, its transport and accumulation. In estimating the oil-gas resources of a basin, the kno...Petroleum science has made remarkable progress in organic geochcmistry and in the research into the theories of petroleum origin, its transport and accumulation. In estimating the oil-gas resources of a basin, the knowledge of its evolutionary history and especially the numerical computation of fluid flow and the history of its changes under heat is vital. The mathematical model can be described as a coupled system of nonlinear partial differentical equations with initial-boundary value problems. This thesis, from actual conditions such as the effect of fluid compressibility and the three-dimensional characteristic of large-scale science-engineering computation, we put forward a kind of characteristic finite element alternating-direction schemes and obtain optimal order estimates in L^2 norm for the error in the approximate assumption.展开更多
This paper proposes a nonmonotonic backtracking trust region algorithm via bilevel linear programming for solving the general multicommodity minimal cost flow problems.Using the duality theory of the linear programmin...This paper proposes a nonmonotonic backtracking trust region algorithm via bilevel linear programming for solving the general multicommodity minimal cost flow problems.Using the duality theory of the linear programming and convex theory,the generalized directional derivative of the general multicommodity minimal cost flow problems is derived.The global convergence and superlinear convergence rate of the proposed algorithm are established under some mild conditions.展开更多
Solution to impedance distribution in electrical impedance tomography （EIT） is an ill-posed nonlinear inverse problem. It is especially difficult to reconstruct an EIT image in the center area of a measured object. ...Solution to impedance distribution in electrical impedance tomography （EIT） is an ill-posed nonlinear inverse problem. It is especially difficult to reconstruct an EIT image in the center area of a measured object. Tikhonov regularization with some prior information is a sound regnlarization method for static electrical impedance tomography under the condition that some true impedance distribution information is known a priori. This paper presents a direct search method （DSM） as pretreatment of image reconstruction through which one not only can construct a regularization matrix which may locate in areas of impedance change, but also can obtain an initial impedance distribution more similar to the true impedance distribution, as well as better current modes which can better distinguish the initial distribution and the true distribution. Simulation results indicate that, by using DSM, resolution in the center area of the measured object can be improved significantly.展开更多
以Web of Science核心合集数据库中的SCI、SSCI和A&HCI引文索引收录的1991-2023年1433篇英文文献为研究样本,使用CiteSpace可视化工具分析了近30年关于他心研究的发文情况、研究热点、前沿与发展趋势。研究发现,欧美国家是他心研究...以Web of Science核心合集数据库中的SCI、SSCI和A&HCI引文索引收录的1991-2023年1433篇英文文献为研究样本,使用CiteSpace可视化工具分析了近30年关于他心研究的发文情况、研究热点、前沿与发展趋势。研究发现,欧美国家是他心研究的主要阵地;哲学与心理学是他心研究的主要领域。研究热点论题包括心智理论、镜像神经元系统、自闭症谱系障碍等,并呈现出对共享意向性、文化进化、直接社会感知、交互式机器人、贝叶斯脑等前沿问题的争论与探索。研究趋势总体呈现出在交叉学科、多元理论背景下认识论与方法论的转变。展开更多
基金supported by the Tianjin Municipal Science and Technology Program of China(No.23JCZDJC00070)。
文摘This paper focuses on the direct and inverse problems for a third-order self-adjoint differential operator with non-local potential and anti-periodic boundary conditions.Firstly,we obtain the expressions for the characteristic function and resolvent of this third-order differential operator.Secondly,by using the expression for the resolvent of the operator,we prove that the spectrum for this operator consists of simple eigenvalues and a finite number of eigenvalues with multiplicity 2.Finally,we solve the inverse problem for this operator,which states that the non-local potential function can be reconstructed from four spectra.Specially,we prove the Ambarzumyan theorem and indicate that odd or even potential functions can be reconstructed by three spectra.
文摘The method in [1] has been extended to the case of rotational flow in this paper. A new method for dealing with the shock wave is presented. This method has the advantages of both the shock-fitting and the shock capturing methods. The direct problem and the mixed direct-inverse prob- lem of the rotational flow in a transonic plane cascade at both design and off design conditions are solved, and the results show that the present method has rapid convergence rate and high accuracy even for the flow with moderately strong shocks. The calculations have been carried out on the DPS-8 computer, and for the direct problem, only 50-80 iterations are needed, and 50-80 seconds of CPU time are required.
文摘Introduction: Orthopaedic surgery includes varieties of injuries and other pathologies. Treatments are complicated while healing and recovery take time. Rehabilitation needs planning and commitment. In the Chinese Communities, traditional medicine has been popular since hundreds of years ago and has remained so in spite of the current advances in medicine. The purpose of this review is to identify the techniques being used in current situations, the indications and problems. Varieties of Traditional Treatments: 1) Topical applications of herbs are very much welcome after joint sprains, inflammatory conditions and even fractures. 2) On the wide area of physical training, the Chinese Tai-chi and Qigong are excellent gentle exercises for personal pursues. These exercises emphasize on body-mind interactions and carry strong philosophical insights. 3) Acupuncture has become standard rehabilitation practice in some hospitals and is getting even more popular in pain control and rehabilitation training after nerve injuries. Problems: Topical agents for pain and inflammation are not totally safe because allergic adverse conditions could happen from time to time. The major concern could be the unawareness of non-unions or delayed unions in fracture cases after herbal applications because the traditional healers are using too little modern assessment tools. Physical trainings and acupunctures are on the whole safe, only that indications are not clearly defined. Future Direction: 1) Concerning the topical agents used for pain and swelling, the essential research requirements include demonstration on the topical agents’ anti inflammatory, angiogenic and cell regenerative effects. The capability of skin penetration needs to be confirmed and a final clinical trial will further confirm the efficacy. 2) Clinical researches trying to obtain evidence on the use of Tai-chi and Qigong on the neuromuscular recovery are plentiful, while their effects on cardiovascular and respiratory health are likewise encouraging. 3) Acupuncture has already become a standard treatment option for pain control, nausea/vomiting and neuromuscular recoveries.
文摘We present a direct algorithm for solving the vertical generalized linear complementarity problem, first considered by Cottle and Dantzig, when the associated matrix is a vertical block P-matrix. The algorithm converges to a unique solution in a finite number of steps, without an assumption of nondegeneracy on the given problem. The algorithm is simple, efficient, and easy to implement.
文摘Objective: To explore the effects of self-directed learning readiness and learning attitude on problem-solving ability among Chinese undergraduate nursing students. Methods: A convenience sampling of 460 undergraduate nursing students was surveyed in Tianjin, China. Students who participated in the study completed a questionnaire that included social demographic questionnaire, Self-directed Learning Readiness Scale, Attitude to Learning Scale, and Social Problem-Solving Inventory. Pearson’s correlation analysis was performed to test the correlations among problem-solving ability, self-directed learning readiness, and learning attitude. Hierarchical linear regression analyses were performed to explore the mediating role of learning attitude. Results: The results showed that learning attitude (r=0.338, P<0.01) and self-directed learning readiness (r=0.493, P<0.01) were positively correlated with problem-solving ability. Learning attitude played a partial intermediary role between self-directed learning readiness and problem-solving ability (F=74.227, P<0.01). Conclusions: It is concluded that nursing educators should pay attention on students’ individual differences and take proper actions to inspire students’ self-directed learning readiness and learning attitude.
文摘Boundary Element Method (BEM) is widely used in electrocardiographic (ECG) problem. Formulations of these problems based on mathematical and numerical approximations of the known source in heart and the volume conductor that can transfer voltages on the surface of the body. To analyze the electric potentials on body surface or epicardial surface, a set of discrete equations derived from a boundary integral equations need to be solved. Solving these equations means to get the potential distribution eventually. In the process of solving, transfer matrix of discrete equations has received considerable attention, how to get an appropriate transfer matrix is an important issue. This paper found that the direction of normal vector could affect the results when calculating the transfer matrix and presents a method analogous to Mesh Current Method to deal with this direction problem. Several simulations have been carried out to verify the accurate results with the correct direction of normal vector using new method within a torso model given simultaneous epicardial and body surface potential recordings.
基金supported by the National Natural Science Foundation of China(Grant Nos.51476043 and 51576053)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.51421063)
文摘An inverse estimation method and corresponding measurement system are developed to measure the apparent spectral directional emissivities of semitransparent materials. The normal spectral emissivity and transmissivity serve as input for the inverse analysis. Consequently, the refractive index and absorption coefficient of the semitransparent material could be retrieved by using the pseudo source adding method as the forward method and the stochastic particle swarm optimization algorithm as the inverse method. Finally, the arbitrary apparent spectral directional emissivity of semitransparent material is estimated by using the pseudo source adding method given the retrieval refractive index and absorption coefficient. The present system has the advantage of a simple experimental structure, high accuracy, and excellent capability to measure the emissivity in an arbitrary direction. Furthermore, the apparent spectral directional emissivity of sapphire at 773 K is measured by using this system in a spectral range of 3 μm-12 μm and a viewing range of 0°-90°. The present method paves the way for a new directional spectral emissivity measurement strategy.
基金National Natural Science Foundation of China, No.41371177, No.71433008 National Social Science Foundation of China, No. 13＆ZD027
文摘Urban agglomerations are an inevitable outcome of China＇s new national industrialization and urbanization reaching relatively advanced stages of development over the past 30 years. In the early 2000 s, urban agglomerations became new geographical units for participating in global competition and the international division of labor, and China has spent the past decade promoting them as the main spaces for pushing forward its new form of urbanization. The convening of the first Central Work Conference on Urbanization and the National New-type Urbanization Plan（2014–2020） further defined the status of urban agglomerations as the main players in promoting China＇s new type of national urbanization. Nevertheless, urban agglomerations remain a weak link in Chinese academia and are in urgent need of study. Only 19 articles on the theme of urban agglomerations were published in the journal Acta Geographica Sinica between 1934 and 2013, accounting for only 0.55% of all articles written during that period. Not only are there very few, they have also all been published within a relatively short period of time, with the first having been published only 10 years ago. The studies are also concentrated among only a few authors and institutions, and research is aimed at national requirements but is rather divergent. Even so, some studies on urban agglomerations have played a leading role and made important contributions to dictating the overall formation of urban agglomerations nationwide. Specifically, a proposed spatial pattern for urban agglomerations formed the basic framework for the spatial structure of China＇s urban agglomerations and guided the government to make urban agglomerations the main urban pattern when promoting the new type of urbanization; proposed standards and technologies for identifying the spatial dimensions of urban agglomerations played an important role in defining the scope of national urban agglomerations; a series of studies in the area of urban agglomerations spurred more in-depth and practical studies in the field; and studies on issues related to the formation and growth of urban agglomerations provided warnings on the future selection and development of urban agglomerations. Taking the progress and results of these studies as a foundation, the foci of selecting and developing urban agglomerations in China are as follows： to be problem-oriented and profoundly reflect on and review new problems exposed in the selection and development of urban agglomerations; to concentrate on urban agglomerations and lay importance on the formation of a new “5＋9＋6” spatial structure for China＇s urban agglomerations; to rely on urban agglomerations and promote the formation of a new pattern of national urbanization along the main axes highlighted by urban agglom-erations; to be guided by national strategic demand and continue to deepen understanding of major scientific issues in the course of the formation and development of urban agglomerations, including studying the resource and environmental effects of high-density urban agglomerations, scientifically examining resource and environmental carrying capacities of high-density urban agglomerations, creating new management systems and government coordination mechanisms for the formation and development of urban agglomerations, studying the establishment of public finance systems and public finance reserve mechanisms for urban agglomerations, and studying and formulating technical specifications for urban agglomeration planning and standards for delineating urban agglomeration boundaries.
文摘We present a direct analytical algorithm for solving transportation problems with quadratic function cost coefficients. The algorithm uses the concept of absolute points developed by the authors in earlier works. The versatility of the proposed algorithm is evidenced by the fact that quadratic functions are often used as approximations for other functions, as in, for example, regression analysis. As compared with the earlier international methods for quadratic transportation problem (QTP) which are based on the Lagrangian relaxation approach, the proposed algorithm helps to understand the structure of the QTP better and can guide in managerial decisions. We present a numerical example to illustrate the application of the proposed method.
基金the National Natural Science Foundation of China (No. 79870030).
文摘As far as the weighted digraph is considered, an optimal directed spanning tree algorithm called table based algorithm (TBA) is proposed in the paper based on the table instead of the weighted digraph. The optimality is proved, and a numerical example is demonstrated.
文摘For the linear least squares problem with coefficient matrix columns being highly correlated, we develop a greedy randomized Gauss-Seidel method with oblique direction. Then the corresponding convergence result is deduced. Numerical examples demonstrate that our proposed method is superior to the greedy randomized Gauss-Seidel method and the randomized Gauss-Seidel method with oblique direction.
基金Project supported by the National Science Foundation,the National Scaling Programthe Doctoral Foundation of the National Education Commission
文摘Petroleum science has made remarkable progress in organic geochcmistry and in the research into the theories of petroleum origin, its transport and accumulation. In estimating the oil-gas resources of a basin, the knowledge of its evolutionary history and especially the numerical computation of fluid flow and the history of its changes under heat is vital. The mathematical model can be described as a coupled system of nonlinear partial differentical equations with initial-boundary value problems. This thesis, from actual conditions such as the effect of fluid compressibility and the three-dimensional characteristic of large-scale science-engineering computation, we put forward a kind of characteristic finite element alternating-direction schemes and obtain optimal order estimates in L^2 norm for the error in the approximate assumption.
基金the National Natural Science Foundation of China ( 1 0 4 71 0 94) ,the ScienceFoundation of Shanghai Technical Sciences Committee ( 0 2 ZA1 40 70 ) and the Science Foundation ofShanghai Education Committee( 0 2 DK0 6)
文摘This paper proposes a nonmonotonic backtracking trust region algorithm via bilevel linear programming for solving the general multicommodity minimal cost flow problems.Using the duality theory of the linear programming and convex theory,the generalized directional derivative of the general multicommodity minimal cost flow problems is derived.The global convergence and superlinear convergence rate of the proposed algorithm are established under some mild conditions.
文摘Solution to impedance distribution in electrical impedance tomography （EIT） is an ill-posed nonlinear inverse problem. It is especially difficult to reconstruct an EIT image in the center area of a measured object. Tikhonov regularization with some prior information is a sound regnlarization method for static electrical impedance tomography under the condition that some true impedance distribution information is known a priori. This paper presents a direct search method （DSM） as pretreatment of image reconstruction through which one not only can construct a regularization matrix which may locate in areas of impedance change, but also can obtain an initial impedance distribution more similar to the true impedance distribution, as well as better current modes which can better distinguish the initial distribution and the true distribution. Simulation results indicate that, by using DSM, resolution in the center area of the measured object can be improved significantly.
文摘以Web of Science核心合集数据库中的SCI、SSCI和A&HCI引文索引收录的1991-2023年1433篇英文文献为研究样本,使用CiteSpace可视化工具分析了近30年关于他心研究的发文情况、研究热点、前沿与发展趋势。研究发现,欧美国家是他心研究的主要阵地;哲学与心理学是他心研究的主要领域。研究热点论题包括心智理论、镜像神经元系统、自闭症谱系障碍等,并呈现出对共享意向性、文化进化、直接社会感知、交互式机器人、贝叶斯脑等前沿问题的争论与探索。研究趋势总体呈现出在交叉学科、多元理论背景下认识论与方法论的转变。
