Search results

This paper aims to present an adaptive sliding mode control (ASMC) for tunnel boring machine cutterhead telescopic system with uncertainties to achieve a high-precision trajectory in complex strata. This method could be applied to solve the problems caused by linear and nonlinear model uncertainties.

First, an integral-type sliding surface is defined to reduce the static tracking error. Second, a projection type adaptation law is designed to approximate the linear and nonlinear redefined parameters of the electrohydraulic system. Third, a nonlinear robust term with a continuous approximation function is presented for handling load force uncertainty and reducing sliding mode chattering. Moreover, Lyapunov theory is applied to guarantee the stability of the closed-loop system. Finally, the effectiveness of the proposed controller is proved by comparative experiments on a scaled test rig.

The linear and nonlinear model uncertainties lead to large variations in the dynamics of the mechanism and the tracking error. To achieve precise position tracking, an adaptation law was integrated into the sliding mode control which compensated for model uncertainties. Besides, the inherent sliding mode chattering was reduced by a continuous approximation function, while load force uncertainty was solved by a nonlinear robust feedback. Therefore, a novel ASMC for tunnel boring machine cutterhead telescopic system with uncertainties can improve its tracking precision and reduce the sliding mode chattering.

To the best of the authors’ knowledge, the ASMC is proposed for the first time to control the tunnel boring machine cutterhead telescopic system with uncertainties. The presented control is effective not only in control accuracy but also in parameter uncertainty.

This study aimed to investigate positive associations between three main motivations (social interaction, information and entertainment) for the use of social network sites (SNSs) and users' well-being, as well as the multiple mediating effects of perceived social support, positive and honest self-presentation.

A sample of 759 active users of SNSs (WeChat Moments, Qzone and Weibo) aged 14–43 years was measured with online questionnaires. Correlation analysis and structural equation modeling were implemented to examine the corresponding hypotheses.

The results showed the overall intensity of motivations was positively associated with users' well-being; perceived social support and positive self-presentation played intermediary roles and honest self-presentation and perceived social support had a chain mediation effect. However, the motivations of social interaction, information and entertainment indirectly affected users' well-being through three different mediation paths.

Although some studies have investigated the effects of motivations (including social interaction, information and entertainment) for SNS use on users' well-being, there has not been a consistent conclusion. The findings may shed light on the motivations for SNS use and how they may affect people's well-being in the digital era, thereby promoting their healthy use of SNSs as well as improved interface design and user management of SNSs.

Project risk management (PRM) and human resource management (HRM) are the two critical success factors (CSFs) for international project management. This paper aims to correlate these two CSFs, identify the human resource (HR) barriers, develop a hybrid model for risk management and develop strategies to overcome the HR barriers to effective risk management in international projects.

In total, 20 key HR barriers have been identified through a literature survey and verified by project professionals. These HR barriers are ranked according to their ability to trigger other barriers by analysing their interactions using the decision-making trial and evaluation laboratory (DEMATEL) method. Based on Ulrich’s revised model for HR functions, a hybrid framework for international PRM has been proposed.

DEMATEL analysis categorized nine barriers as cause barriers and 11 as affected barriers. The “PROJECTS” model proposed for HR strategy development suggests eight strategies to overcome these nine cause barriers. The hybrid PRM framework developed includes the effect of the HR dimension.

This paper presents the generalized prioritization of HR barriers to international PRM. For a specific international project, the HR barriers and their prioritization may change slightly. The hybrid framework for PRM and the strategy development model suggested are yet to be validated.

Correlating two CSFs in international project management, i.e. HRM and PRM and ranking the HR barriers using the DEMATEL method is the uniqueness of this research paper. The hybrid framework developed for PRM based on HR functions in Ulrich’s revised model and the proposed new HR strategy development model “PROJECTS” are unique contributions of this paper.

The purpose of this paper is to give a comprehensive survey on the physics-based virtual assembly (PBVA) technology in a novel perspective, to analyze current drawbacks and propose several promising future directions.

To provide a deep insight of PBVA, a discussion of the developing context of PBVA and a comparison against constraint-based virtual assembly (CBVA) is put forward. The core elements and general structure are analyzed based on typical PBVA systems. Some common key issues as well as common drawbacks are discussed, based on which the research trend and several promising future directions are proposed.

Special attention is paid to new research progresses and new ideas concerning recent development as well as new typical systems of the technology. Advantages of PBVA over CBVA are investigated. Based on the analysis of typical PBVA systems and the evolution of PBVA, the core elements of the technology and the general structure of its implementation are identified. Then, current PBVA systems are summarized and classified. After that, key issues in the technology and current drawbacks are explored in detail. Finally, promising future directions are given, including both the further perfecting of the technology and the combination with other technologies.

The PBVA technology is put into a detailed review and analysis in a novel way, providing a better insight of both the theory and the implementation of the technology.

This paper aims to understand the influences of tris (2-hydroxyethyl) isocyanurate oleate and oleic acid tris (2-hydroxyethyl) isocyanurate phosphate ester on biodegradability and tribological performances of mineral lubricating oil.

Tris (2-hydroxyethyl) isocyanurate oleate and oleic acid tris (2-hydroxyethyl) isocyanurate phosphate ester were prepared and characterized by Fourier transform infrared spectrometer. The biodegradability and tribological properties of neat oil and its formulations were studied on a tester for fast evaluating biodegradability of lubricants and a four-ball tester, respectively. The worn surfaces were investigated by scanning electron microscope and X-ray photoelectron spectroscope.

Tris (2-hydroxyethyl) isocyanurate oleate and oleic acid tris (2-hydroxyethyl) isocyanurate phosphate ester both improved markedly the biodegradability, the anti-wear properties, friction-reducing properties and extreme pressure properties of base oil. The effect of oleic acid tris (2-hydroxyethyl) isocyanurate phosphate ester was better than tris (2-hydroxyethyl) isocyanurate oleate. The improvement of tribological performances was mainly ascribed to the formation of a complicated boundary lubrication film of tris (2-hydroxyethyl) isocyanurate oleate and oleic acid tris (2-hydroxyethyl) isocyanurate phosphate ester on the friction surfaces.

This paper has indicated that tris (2-hydroxyethyl) isocyanurate oleate and oleic acid tris (2-hydroxyethyl) isocyanurate phosphate ester effectively improve the biodegradability and tribological performances of mineral lubricating oil. Promoting biodegradation of mineral lubricant by additives is very significant for the development of petroleum-based biodegradable lubricants. These two additives not merely improve the tribological performances; more importantly, they improve the ecological performances.

This purpose of this paper is to design a peg-in-hole controller for a cable-driven serial robot with compliant wrist (CDSR-CW) using cable tensions and joint positions. The peg is connected to the robot link through a CW. It is required that the controller does not rely on any external sensors such as 6-axis wrist force/torque (F/T) sensor, and only the compliance matrix’s estimated value of the CW is known.

First, the peg-in-hole assembly system based on a CDSR-CW is analyzed. Second, a characterization algorithm using micro cable tensions and joint positions to express the elastic F/T at the CW is established. Next, under the premise of only knowing the compliance matrix’s estimate, a peg-in-hole controller based on force/position hybrid control is proposed.

The experiment results show that the plug contact F/T can be tracked well. This verifies the validity and correctness of the characterization algorithm and peg-in-hole controller for CDSR-CWs in this paper.

First, to the authors’ knowledge, there is no relevant work about the peg-in-hole assembly task using a CDSR-CW. Besides, the proposed characterization algorithm for the elastic F/T makes the peg-in-hole controller get rid of the dependence on the F/T sensor, which expands the application scenarios of the peg-in-hole controller. Finally, the controller does not require an accurate compliance matrix, which also increases its applicability.

This study aims to investigate the factors and mechanism which influence the doctor’s social and economic benefits from the perspective of social capital.

This paper mainly investigates the factors and mechanism influencing the doctor's social and economic benefits from the perspective of social capital and then constructs a doctor's social capital model and discusses the effects of doctor's social capital on their economic and social benefits; what is more, this paper also considers the moderating effect of patients’ group behavior.

The results show that the doctor's social capital has a positive and significant effect on doctor's economic benefits, while it has a negative and significant effect on doctors' social benefits. Patients’ group behavior plays an important moderating role; in particular, the number of online patients of doctors can effectively strengthen follow-up patients’ positive perception of the doctor capital, while the number of offline patients has a negative effect on doctors’ economic benefits, but it can reduce its negative impact on doctors’ social benefits by establishing trust between patient and physician.

This paper enriches the relevant research of social capital theory in the medical field and broadens the research about online health care. For platforms, they should give more attention to doctors and their income issues, which is of great significance for their healthy and sustainable development.

The purpose of this paper is to investigate the relationship between e-marketing (eM) and consumers’ buying behavior particularly exploratory buying behavior tendencies (EBBT) with moderating effect of a gender in the context of China.

Structural equation modeling using SPSS/AMOS was majorly applied to ascertain the relationship and hypotheses testing. First, the correlation of eM toward EBBT is examined using five factors: internet marketing (IM), e-mail marketing (EMa), intranet marketing (IMa), extranet marketing (EM), and mobile marketing (MM). Second, the relationship of each dimension of the eM model is determined autonomously to ensure the importance of such emerging technologies in marketing communications. Third, the effect of gender as a moderator is measured. To this end, primary data were collected through random distribution of the questionnaires among 1,600 consumers particularly students of the universities between February 2016 and August 2016 within North China.

The findings revealed that eM has a significant correlation on consumers’ EBBT. The comprehensive analysis of each factor of eM, i.e., IM, EMa, IMa, EM, and MM is positively correlated to EBBT. The present study revealed that gender did not moderate among the relationships of eM and EBBT. Additionally, study furnishes practical directions on how managers can utilize such emerging and revolutionary technologies in marketing activities to probe, understand, and reinforce consumers’ buying behavior.

The research has limitations related to geographical location and sample size which thus limits the widespread generalization.

This study affirmed that organizations must engage the consumers using such technologies that are more likely acceptable by consumers in the present customer-oriented and digital era. The marketers must engage consumers the way they wish to be engaged by developing appropriate promotional strategies. The study provides possible implications both theoretical and managerial along with a contribution to the literature of eM and consumers’ buying behavior.

Understanding the emerging technologies may furnish valuable insights for individuals to work well within Chinese SMEs.

The topic of eM has acknowledged as an evolving concept which is gaining an intense concern of both academician and practitioners. Therefore, more research mainly empirical work is still needed to probe the insights of eM across the globe. This study attempts to fulfill such need with empirical evidence together with an in-depth examination of eM determinants, collectively and autonomously.

Recently, sharing economy is gradually accepted by people, and it has expanded from life to knowledge. It is important to encourage people to produce high quality content in knowledge sharing area, and knowledge payment is one of the most effective ways to achieve it. Therefore, the knowledge payment has been regarded as a huge business opportunity, and it is of great meaning to study the development trend and feasibility of knowledge payment. This chapter, through big data methods, analyzes the business model of Zhihu (a Chinese platform of knowledge sharing) after it introduced knowledge payment projects, such as Zhihu Live and Pay Consultation. According to data of Zhihu users’ Q&A, concerned fields and others, this chapter tries to outline its user profile to find out the target groups of different topics, the proper form of knowledge payment and the hot topics of Zhihu Live. Through the analysis of knowledge graph, this chapter finds that Zhihu Live is expected to be the mainstream knowledge payment form in the future, and the most potential topics are mainly focused on science, law, and business. Meanwhile, it establishes a pricing model for Zhihu Live, and provides suggestions for the development of knowledge payment.

Entrepreneurship.

This case is suitable for MBA, EMBA and advanced undergraduate students.

Noah Wealth Management was founded by Ms Wang Jingbo, a lady in her mid 30s with a team of less than 20 members in 2005. Exploiting market opportunities offered by a lack of good wealth management products and services, Noah grew rapidly from one branch office in 2005 to 59 branch offices in 2011, reaching a staff size of 1,031. Noah listed its shares on the New York Stock Exchange in November 2010. In 2011, Noah was ranked No. 38 among the 100 Top Potential Enterprises in China. Nonetheless, Noah faced several problems of internal management during the course of its fast expansion. In the first quarter financial report of 2012, Noah suffered a 52.6 percent decrease in net income over the corresponding period in 2011. Faced with a rapidly declining share price, Noah announced on May 22, 2012 a US $30 million share repurchase program.

The case supports a basic lesson on the entrepreneurial cycle, including assessing a business opportunity, resource mobilization, identifying a business model, growth of the venture, listing on the stock market, and subsequent growth challenges. Students can learn about some of the typical dilemmas faced by founders of entrepreneurial ventures, including how to maintain the corporate culture while growing fast and how to prevent members of the founding team from becoming bottlenecks to the development of the organization. The case can also provide management students with an overview of China's wealth management industry.

Teaching notes are available for educators only. Please contact your library to gain login details or email support@emeraldinsight.com to request teaching notes.