Search results

The purpose of this paper is to preset a spherical element subdivision method for the numerical evaluation of nearly singular integrals in three-dimensional (3D) boundary element method (BEM).

In this method, the source point is first projected to the tangent plane of the element. Then two cases are considered: the projection point is either inside or outside the element. In both cases, the element is subdivided into a number of patches using a sequence of spheres with decreasing radius.

With the proposed method, the patches obtained are automatically refined as they approach the projection point and each patch of the integration element is “good” in shape and size for standard Gaussian quadrature. Therefore, all kinds of nearly singular boundary integrals on elements of any shape and size with arbitrary source point location related to the element can be evaluated accurately and efficiently.

Numerical examples for planar and slender elements with various relative location of the source point are presented. The results demonstrate that our method has much better accuracy, efficiency and stability than conventional methods.

This paper aims to propose a boundary element analysis of two-dimensional linear elasticity problems by a new expanding element interpolation method.

The expanding element is made up based on a traditional discontinuous element by adding virtual nodes along the perimeter of the element. The internal nodes of the original discontinuous element are referred to as source nodes and its shape function as raw shape function. The shape functions of the expanding element constructed on both source nodes and virtual nodes are referred as fine shape functions. Boundary variables are interpolated by the fine shape functions, while the boundary integral equations are collocated on source nodes.

The expanding element inherits the advantages of both the continuous and discontinuous elements while overcomes their disadvantages. The polynomial order of fine shape functions of the expanding elements increases by two compared with their corresponding raw shape functions, while the expanding elements still keep independence to each other as the original discontinuous elements. This feature makes the expanding elements able to naturally and accurately interpolate both continuous and discontinuous fields.

Numerical examples are presented to verify the proposed method. Results have demonstrated that the accuracy, efficiency and convergence rate of the expanding element method.

The purpose of this paper is to present a fast algorithm for the adaptive discretization of three-dimensional parametric curves.

The proposed algorithm computes the parametric increments of all segments to obtain the parametric coordinates of all discrete nodes. This process is recursively applied until the optimal discretization of curves is obtained. The parametric increment of a segment is inversely proportional to the number of sub-segments, which can be subdivided, and the sum of parametric increments of all segments is constant. Thus, a new expression for parametric increment of a segment can be obtained. In addition, the number of sub-segments, which a segment can be subdivided is calculated approximately, thus avoiding Gaussian integration.

The proposed method can use less CPU time to perform the optimal discretization of three-dimensional curves. The results of curves discretization can also meet requirements for mesh generation used in the preprocessing of numerical simulation.

Several numerical examples presented have verified the robustness and efficiency of the proposed algorithm. Compared with the conventional algorithm, the more complex the model, the more time the algorithm saves in the process of curve discretization.

In Beijing, urban agriculture (UA) experienced a corkscrew development with its role changing in decades: It has evolved from the purely production mode to multi-functional urban agriculture, fulfilling both social and ecological demands. At present, the practice of UA as well as the number of rural to urban migrants is growing rapidly in peri-urban Beijing. Through Multi-stakeholder Process for Action planning and Policy Design (MPAP) methodology and four in-depth case studies, we can see that UA activities are playing very important roles in reshaping peri-urban Beijing. Socially, UA induces the emergence of new migrant communities. While migrants rebuild their social network, they are changed by the city as well, which has also changed the local community. The new comers are on their way to creating a new balance. Physically, urban and peri-urban farmland limits urban sprawl, supplies agricultural products for everyday life, and reserves urban green spaces for recreation and leisure for citizens in Beijing, which has changed the landscape and land use and land cover (LUCC) pattern greatly. Under Beijing's land policy, the concentric configuration spatial allocation through multi-functional UA is formed, which at the same time due to migrants' UA activities are creating harmful and low efficient land use pattern which should be of concern.

The purpose of this study is to reveal the mechanism of humble leadership inducing abusive supervision from the low-status compensation perspective, examining the mediation role of leader perceived thread to status. Besides, the moderation effect of regulatory focus on the mediation path is discussed.

This study conducted a three-wave longitudinal survey. The data was collected from 438 leaders and their employees in five Chinese enterprises. This study used Mplus 7.4 and adopted a bootstrapping technique for data analysis.

Humble leadership has a positive effect on leader perceived threat to status. Leader perceived threat to status plays a mediation role between humble leadership and leader abusive supervision. Leader regulatory focus is the “gate valve” that humble leadership fosters leader abusive supervision. That is, when the leader promotion focus is high, leader perceived threat to status bred by humble leadership is low, resulting in less abusive supervision. When the leader prevention focus is high, humble leadership brings relatively more abusive supervision through perceived threat to status.

This study explores why humble leadership breeds abusive supervision behaviors and reveals the mechanism behind the negative effect of humble leadership based on low-status compensation theory. This study not only promotes the continuous development of the field of humble leadership research through empirical research but also provides guidance for effectively suppressing the negative effects of humble leadership, promoting strengths and avoiding weaknesses and suppressing inappropriate management behaviors in management practice.

The purpose of this paper is to investigate the impact of native Chinese R&D team directors’ differential leadership on team performance, so as to understand whether and how the directors’ differential leadership impacts team conflict, whether and how team conflict impacts new product development performance of the R&D team and whether team conflict plays full mediation on the relationship between directors’ differential leadership and new product development performance.

A literature review on differential leadership and team conflict provided the model and hypothesis. Two-wave data collected from 103 directors and 344 subordinates from 103 R&D teams of high-tech enterprises from China’s Pearl River Delta Area were used as empirical study samples. Hierarchical multiple regression analysis was conducted to test the model and hypothesis.

First, the team director’s differential leadership would cause significant team relationship conflict and team task conflict in the R&D team. Second, team relationship conflict and team task conflict would produce significantly bad new product development performance in the R&D team. Third, team relationship conflict would significantly mediate the relationship between the team director’s differential leadership and the team’s new product development performance.

To yield broader conclusions and to show to that the results can be replicated in other areas or in other types of organizations, further empirical research should expand the sampling by choosing high-tech enterprises from Beijing and Shanghai that have strong innovative abilities. Moreover, to extend the differential leadership theory, few more related variables of consequences, such as team communication, team cooperation and team knowledge share, should be included in future studies.

In general, the native Chinese R&D department director needs to try their best to avoid the use of differential leadership style. In addition, reasonable incentive measures, promotion mechanisms and fair team work culture are needed so as to reduce the negative impact from the director’s differential leadership.

The paper is original in its investigation on how Chinese indigenous organizational factor – differential leadership – influences the R&D team’s conflict and new product development performance, and provides theoretical contribution and managerial implications for the R&D team management.

Electrical impedance tomography (EIT) is a technique for reconstructing the conductivity distribution by injecting currents at the boundary of a subject and measuring the resulting changes in voltage. Image reconstruction for EIT is a nonlinear problem. A generalized inverse operator is usually ill-posed and ill-conditioned. Therefore, the solutions for EIT are not unique and highly sensitive to the measurement noise.

This paper develops a novel image reconstruction algorithm for EIT based on patch-based sparse representation. The sparsifying dictionary optimization and image reconstruction are performed alternately. Two patch-based sparsity, namely, square-patch sparsity and column-patch sparsity, are discussed and compared with the global sparsity.

Both simulation and experimental results indicate that the patch based sparsity method can improve the quality of image reconstruction and tolerate a relatively high level of noise in the measured voltages.

EIT image is reconstructed based on patch-based sparse representation. Square-patch sparsity and column-patch sparsity are proposed and compared. Sparse dictionary optimization and image reconstruction are performed alternately. The new method tolerates a relatively high level of noise in measured voltages.

“Library + cultural tourism” (LCT) is a new direction for the sustainable development of libraries, but few scholars have researched it from a tourist perspective. The purpose of this paper is to identify what factors affect tourist satisfaction (TS) with LCT, reveal the interaction among these factors and provide strategies for better library services.

This study collected 5,308 comments on Tianjin Binhai Library from three popular online travel communities. Grounded theory was adopted to identify what factors affect TS with LCT and reveal the interaction among these factors.

The results indicated that TS with LCT was affected by complex factors related to tour plans, tour expectations, cultural characteristics, environment, support services and emotions. Cultural characteristics, environment and support services were impacted by tour plans and tour expectations, which directly or indirectly affected TS mediated by emotions. TS further influenced their expectation of their next tour.

This paper uncovered critical problems with LCT using a case study of Tianjin Binhai Library. The results provide a reference for library practitioners to develop better library services for tourists and regular users/readers.

Discusses the application of the fixed interface modal synthesis technique and the quasi‐ periodically symmetric feature of the shrouded blades and disc system for analysing the coupling vibration characteristic of a system which has freely slipping contact surfaces. This technique has led to the establishment of an entirely new dynamic analysis method. With this method, the scale of calculation required has been greatly reduced, relieving the demand on CPU time and storage capacity while still ensuring sufficient accuracy of dynamic analysis.