Search results

With the booming development of computer, optical and sensing technologies and cybernetics, the technical research in unmanned vehicle has been advanced to a new era. This trend arouses great interest in simultaneous localization and mapping (SLAM). Especially, light detection and ranging (Lidar)-based SLAM system has the characteristics of high measuring accuracy and insensitivity to illumination conditions, which has been widely used in industry. However, SLAM has some intractable problems, including degradation under less structured or uncontrived environment. To solve this problem, this paper aims to propose an adaptive scheme with dynamic threshold to mitigate degradation.

We propose an adaptive strategy with a dynamic module is proposed to overcome degradation of point cloud. Besides, a distortion correction process is presented in the local map to reduce the impact of noise in the iterative optimization process. Our solution ensures adaptability to environmental changes.

Experimental results on both public data set and field tests demonstrated that the algorithm is robust and self-adaptive, which achieved higher localization accuracy and lower mapping error compared with existing methods.

Unlike other popular algorithms, we do not rely on multi-sensor fusion to improve the localization accuracy. Instead, the pure Lidar-based method with dynamic threshold and distortion correction module indeed improved the accuracy and robustness in localization results.

Improving audit quality is an important research area of managerial accounting. This study focuses on the informal institutions within organizations and their impact on audit quality. Specifically, this study aims to examine the impact of the informal hierarchy among directors on audit quality.

The authors examine Chinese companies with listed shares from 2008 to 2020. The authors proxy for audit quality using discretionary accruals and small profits, and use ordinary least squares regression to test their hypotheses.

The results demonstrate that the informal hierarchy of the board improves audit quality. The results are robust to a battery of sensitivity analyses. Additionally, there is weak evidence that the effect of the board’s informal hierarchy on audit quality is weaker in state-owned enterprises. Moreover, the mechanism tests indicate that the board’s informal hierarchy improves audit quality through the improvement of internal controls. In addition, the impact of the informal hierarchy among directors on audit quality further improves firm performance. However, audit fees are not reduced further because the board’s informal hierarchy demands higher audit quality by choosing industry audit experts.

This study not only enriches the research on the economic consequences of the board’s informal hierarchy but also expands on studies on antecedents of audit quality.

The purpose of this paper is to examine the push and pull factors associated with the consumption of Chinese Table Tennis Super League (CTTSL) game events by online audiences and on-site attendants.

Conducting a comprehensive review of literature and a test of content validity, a questionnaire was formulated to assess push and pull motives, event consumption, and sociodemographic variables. A total of 433 CTTSL event consumers, including 225 respondents who primarily followed CTTSL game events via television and webcasting and 208 respondents who primarily consumed the events by attending live game events.

Structural equation modeling analyses revealed that for online consumers, two push factors, self-esteem and drama excitement, were found to be positively related to the event consumption factors; whereas, social interaction and sport performance factors were found to be negatively predictive of event consumption factors. For on-site consumers, none of the push and pull factors were found to be related to the consumption factors.

These results indicate that unlike research findings derived in other research settings mainly conducted in Western countries, push and pull factors are more functional for online CTTSL consumers who are of comparatively stronger fandom level, which are likely affected by CTTSL’s contemporary operations.

Enriching the dual process theory through examining its applicability in studying sport consumer behavior, from both perspectives of internal and external motivations; applying theories and research findings of internal and external motivations that have primarily been derived in Western countries into a professional sport setting in China; identifying unique and diverse perspectives of professional table tennis consumers in China between online and on-site consumers; contrary to the findings derived in Western countries, the motivational factors are more functional for online CTTSL consumers who are of comparatively stronger fandom level, which are likely affected by CTTSL’s contemporary operations; and conducting micro-perspective analyses to study Chinese sport consumer behaviors, which has rarely been done in contemporary scholarly inquiries in China.

The economy of China has developed rapidly, and its international status has quickly risen in the past 30 years. China is shifting from a major exporter into a major consumer, becoming an essential part of the international market. However, some global brands make wrong market decisions because of a lack of understanding of Eastern consumer culture.

Based on consumer xenocentrism, this paper helps global enterprises better understand Chinese consumers' psychology in foreign goods, which is conducive to the development of transnational trade. This study proposes a hypothesis model based on previous literature. The authors collected 300 questionnaires from China and tested the model by SPSS24 and AMOS24.

The findings show that curiosity and country of origin positively affect consumer xenocentrism, consumer xenocentrism has a positive impact on word-of-mouth and purchase intention, word-of-mouth plays a mediating role in xenocentrism and purchase intention and social comparison tendency plays a moderating role in consumer xenocentrism and purchase intention. Simultaneously, this paper develops a scale measuring consumer xenocentrism to provide some quantitative support for this research.

The authors propose some suggestions basing on the research of consumer xenocentrism and provide some further directions.

By using table tennis as an example and conducting an in-depth investigation into the impact of market demand factors on membership consumption of table tennis club members in the USA, the purpose of this paper is to illustrate the opportunities and marketing efforts needed for Asian sports to survive and thrive in North America, in which consumer demand factors assessing core program features of table tennis clubs were found to be very influential of cognitive, affective, and behavioral consumptions of table tennis club members.

Through conducting a review of literature, observations of club operations, and interviews of club administrators and club members representing various table tennis clubs, a preliminary questionnaire was formulated for this study. The initial questionnaire was submitted to a panel of five experts, for a test of content validity. By incorporating their suggestions, editing was made to improve a number of the items in the questionnaire. Data collection took place in two national table tennis tournaments, two local tournaments, and six table tennis clubs. Procedures in SPSS 19.0 (SPSS, 2009) and Mplus 5.21 were carried out for data analyses.

The findings of this study are that market demand factors would be significantly related to consumer perceived benefits and perceived value, and in turn related to consumer satisfaction of table tennis club membership. The market demand factors had a positive impact on perceived value and benefits confirmed the theoretical framework and previous research findings, which also made a practical sense that a table tennis club needs to offer product features and meet expectations of its current and potential members in order to enhance program value and benefits perceived by its members.

The past two decades have marked the speediest rise of a globalized sport production and consumption trend. In an era of globalized sport marketplace, sports have become a business commodity to meet the needs of commerce. For an Asian sport to penetrate into the North American marketplace as table tennis has done, it would be wise to develop regional network, strategies, product, and promotions. It is expected that table tennis as a popular Asian sport will continue being spread to other parts of the world; thus, the findings of this study have potential relevance to promoting table tennis globally.

The purpose of this paper is to construct the algebraic traveling wave solutions of the (3 + 1)-dimensional modified KdV-Zakharov-Kuznetsve (KdV-Z-K) equation, which can be usually used to express shallow water wave phenomena.

The authors apply the planar dynamical systems and invariant algebraic cure approach to find the algebraic traveling wave solutions and rational solutions of the (3 + 1)-dimensional modified KdV-Z-K equation. Also, the planar dynamical systems and invariant algebraic cure approach is applied to considered equation for finding algebraic traveling wave solutions.

As a result, the authors can find that the integral constant is zero and non-zero, the algebraic traveling wave solutions have different evolutionary processes. These results help to better reveal the evolutionary mechanism of shallow water wave phenomena and find internal connections.

The paper presents that the implemented methods as a powerful mathematical tool deal with (3 + 1)-dimensional modified KdV-Z-K equation by using the planar dynamical systems and invariant algebraic cure.

By considering important characteristics of algebraic traveling wave solutions, one can understand the evolutionary mechanism of shallow water wave phenomena and find internal connections.

To the best of the authors’ knowledge, the algebraic traveling wave solutions have not been reported in other places. Finally, the algebraic traveling wave solutions nonlinear dynamics behavior was shown.

This paper aims to clarify the relationship between the cone bit seal failure and the down-hole drilling fluid pressure and high temperature that occur during ultra-deep well drilling. It proposes that the contact pressure distribution under low pressure conditions is favourable for lubrication and the seal inner wear is serious under high pressure conditions. Furthermore, the more reliable cone bit seal can be obtained using the back propagation (BP) neural network and genetic algorithm (GA) to reduce the drilling cost.

The wear morphologies of the seal surface were analyzed using Contour GT-K to determine the seal contact pressure distribution. Then, the influences of the drilling fluid pressure and high temperature on the metal seal interface were analyzed using finite element method. The structural parameters of the seal under high pressure were optimized based on the BP neural network and GA.

This paper proposes that the inner seal contact pressure increases rapidly with an increase in the drilling fluid pressure. The design parameters of the seal components should be adjusted reasonably to ensure that the outer contact pressure is greater than the inner contact pressure, which is advantageous for forming a lubricant film on the inner side of the seal. The uneven temperature distribution of the seal surface will further aggravate seal failure.

Study on the bit seal with good property is significant in drilling application, and the optimized seal can prolong the cone bit life.

This paper aims to present a simplified solution method for the elasto-plastic consolidation problem under different stress paths.

First, a double-yield-surface model is introduced as the constitutive model framework, and a partial derivative coefficient sequence is obtained by using numerical approximation using Gauss nuclear function to construct a discretization constitutive model which can reflect the influence of different stress paths. Then, the model is introduced to Biot’s consolidation theory. Volumetric strain of each step as the right-hand term, the continuity equation is simplified as a Poisson equation and the fundamental solution is derived by the variable separation method. Based on it, a semi-analytical and semi-numerical method is presented and implemented in a finite element program.

The method is a simplified solution that is more convenient than traditional coupling stiffness matrix method. Moreover, the consolidation of the semi-infinite foundation model is analyzed. It is shown that the numerical method is sufficiently stable and can reflect the influence of stress path, loading distribution width and some other factors on the deformation of soil skeleton and pore water pressure.

Original features of this research include semi-numerical semi-analytical consolidation method; pore water pressure and settlements of different stress paths are different; maximum surface uplift at 3.5a; and stress path is the main influence factor for settlement when loading width a > 10 m.

Taking 30 provincial samples from 2001 to 2017 in mainland China as the research objects, this paper aims to evaluate the impact and effects of foreign direct investment (FDI) on the urban–rural income gap and reveals heterogeneity across regions.

Firstly, the Theil index is used to measure the income gap between 30 provinces in mainland China from 2001 to 2017, then the spatial econometric model is used to empirically test the impact of foreign direct investment on China’s urban–rural income gap and its heterogeneity across regions. Finally, a robustness test is performed.

The results show that there is a significant inverted U-shaped relationship between FDI and the urban–rural income gap in China. That is, FDI expands the urban–rural income gap in the short term and helps to converge it in the long term. In the eastern region, FDI has a convergence effect on the urban–rural income gap in the short term, which increases the long term. However, in the central and western regions, the relationship between FDI and urban–rural income gap has a weak inverted U shape.

By assessing the impact of FDI on the urban–rural income gap, this work provides decision-making support for China and other developing countries to improve investment policies and income distribution policies.