Search results

The purpose of this paper is to analyze the cavitation characteristics of a water hydraulic axial piston motor (WHAPM) to improve the water motor performance, to reduce the vibration and noise and to prolong the service life of the motor.

The computational fluid dynamics (CFD) software PumpLinx is chosen to do cavitation analysis of the WHAPM. In this case, first, cavitation mechanism of the water piston motor is analyzed in depth. Then, considering the effects of bubble dynamics, the rate of phase transition, turbulence effects and non-condensable gas, the full cavitation model is selected, the dynamic CFD numerical model of internal flow field on the water hydraulic piston motor is established based on PumpLinx software and the fluid cavitation inside is numerically studied. Finally, the influence of the valve plate and pistons on motor cavitation is analyzed.

Research results show that there are two serious cavitation regions: one is the pressure transition region of the valve plate that is near the top dead center, and the other is the low-pressure region of the piston that is near the low-pressure transition area. Moreover, the more serious cavitation area is on the valve plate region.

The simulation results show that the proposed algorithm is able to detect the cavitation characteristics of the water piston motor. Besides, it is deduced that valve-plate structure optimization is more important than pistons to reduce cavitation influence.

The paper aims to provide an efficient meta-heuristic algorithm to solve the partial set covering problem (PSCP). With rich application scenarios, the PSCP is a fascinating and well-known non-deterministic polynomial (NP)-hard problem whose goal is to cover at least k elements with as few subsets as possible.

In this work, the authors present a novel variant of the ant colony optimization (ACO) algorithm, called Argentine ant system (AAS), to deal with the PSCP. The developed AAS is an integrated system of different populations that use the same pheromone to communicate. Moreover, an effective local search framework with the relaxed configuration checking (RCC) and the volatilization-fixed weight mechanism is proposed to improve the exploitation of the algorithm.

A detailed experimental evaluation of 75 instances reveals that the proposed algorithm outperforms the competitors in terms of the quality of the optimal solutions. Also, the performance of AAS gradually improves with the growing instance size, which shows the potential in handling complex practical scenarios. Finally, the designed components of AAS are experimentally proved to be beneficial to the whole framework. Finally, the key components in AAS have been demonstrated.

At present, there is no heuristic method to solve this problem. The authors present the first implementation of heuristic algorithm for solving PSCP and provide competitive solutions.

The purpose of the study is to explore how technological capability and exogenous pressure interactively influence business model (BM) dynamics over time in new technology-based ventures.

The study adopts a longitudinal case study of the BM innovations of a Chinese financial technology venture. The structural approach and temporal bracket are used to analyze and theorize the data.

The findings indicate that distinct contextual changes impel a firm to refine or abandon existing BMs over time. In different stages, the antecedents interactively influence BM dynamics with three successive patterns, namely pressure dominance, parallel influence and hybrid influence. While both antecedents trigger changes during the initiation and implementation of new BMs, they also serve as the filter and the enabler, respectively, during the ideation and integration of BMs.

The study inductively develops three propositions regarding the relationship between BM dynamics and its antecedents, which is based on the data collected from one single firm. Future research should test the propositions in other domains and take more cross-level antecedents into consideration.

The study contributes to the nascent research stream of BM dynamics by offering in-depth insights into the interaction of internal and external antecedents and by linking the differentiated roles of antecedents to the BM innovation process. The research offers some practical implications for new technology-based ventures seeking to develop BMs in a fast-changing environment.

Student approaches to studying were explored in business courses with samples in China, Kuwait and the USA. Information on approaches to studying is critical as delivery and content of educational practices are increasingly adapted to different world regions.

The Revised Approaches to Studying Inventory (RASI) was administered to address the extent to which students focused studying on deep learning of concepts, surface learning/memorization of material or strategic maximization of grades.

Results suggested (1) acceptable reliability for the RASI scales, (2) higher mean scores on deep, surface and strategic approaches for the Kuwait versus the China or USA samples, and (3) an interaction effect between country sample and strategic studying on the dependent variable of reported grade point average.

The research focuses on student initiative in the educational process. Also, comparative evidence from the Middle Eastern context is provided. This area has received relatively little attention in the literature.

In the face of fierce international competition for those participating in global value chains (GVCs), upgrading has been a central concern of emerging market firms (EMFs) that are trying to occupy higher value-added positions. However, although the innovation capabilities (ICs) have been generally considered critical to upgrading in GVCs, few studies have examined how IC is built up and then applied to the EMF upgrading process over time. To this end, the purpose of this paper is to investigate why and how EMFs can upgrade in GVCs through the development of their IC.

This paper adopts a multiple-case study of three supplier firms in China and their IC development processes, with a special focus on the nature of the firm-level upgrading in GVCs.

The results generate a process model of EMFs upgrading with respect to the development of IC. The model reveals how IC is built up through the firms' underlying systematic innovation activities, which enable firms to successfully upgrade within GVCs. In particular, the role played by contextual vulnerability in guiding firms to develop the appropriate IC, and the corresponding upgrading, is highlighted.

This study contributes to the micro-foundation in GVCs literature, especially the traditional static upgrading research of EMFs. The authors also contribute to existing IC development research. Meanwhile, the study focuses on the upgrading of three Chinese firms in the phone and LED industries. The generalizability to other emerging markets and industries may therefore be limited.

The study results show that EMFs could initially develop endogenous IC that focuses on process innovation as a means to establish a foundation for further upgrading. In addition, firms need to improve their ability to accurately sense contextual changes. As such, it would be valuable to understand their positions and characteristics within GVCs.

This paper investigates a process model of upgrading in GVCs through IC development in EMFs. This study also adds a dynamic micro-foundation to existing, rather macro and static GVCs studies.

The rapid growth of emerging market firms (EMFs) has been a topic of interest for the past two decades, especially in China. However, few studies have discussed how and why EMFs can impel the upgrading of their capabilities to quickly win competitive advantages in the global market. In this context, the purpose of this paper is to unravel the implausible upgrading phenomenon from the perspective of technological proximity.

This paper adopts a single case study, specifically that of a leading Chinese e-bike firm, with a special focus on the dynamic nature of the capability upgrading process and underlying mechanisms.

The results show that taking advantage of technological proximity is an important way for EMFs to climb the ladder of capability upgrading. The stage-based process reveals how capability upgrading is achieved through elaborate actions related to technological proximity. Furthermore, this study finds three learning mechanisms behind the technological proximity, which enable firms to successfully upgrade to higher levels of capabilities. In particular, the trigger role played by contextual conditions in guiding firms' capability upgrading is highlighted and characterized.

This study enriches traditional capability upgrading literature from a technological proximity perspective, especially the traditional static upgrading research related to EMFs. The authors also contribute to the conceptualization of technological proximity. However, the research setting is China's e-bike industry; therefore, the study's generalizability to other emerging markets and industries may be limited.

The results show that it is important to recognize the value of the transfer and sharing of technology between proximal industries for local governments. Also, appropriate policies should be developed to break down the technology barriers between these industries. Moreover, rather than catching up with the superior technologies of multinational corporations in advanced countries, focusing on products with high technological proximity in local or regional areas may be more helpful for EMFs' upgrading.

This paper investigates the capability upgrading process and mechanisms in EMFs, particularly with respect to the role played by technological proximity.

Recently, the concept of financial technology (FinTech) has attracted extensive attention from international organisations and regulators, in particular, how to achieve a “win–win” situation between financial institutions' FinTech innovation and effective regulation has become a hot topic. This study purposes to explore the evolutionary game relationship between FinTech innovation and regulation by constructing both static and dynamic earmarking game models.

A simulation experiment was conducted using primary data obtained from a commercial bank in China.

The results of the theoretical analysis of evolutionary game models were consistent with the corresponding simulation results, proving the validity of the proposed evolutionary game models. It was also found that the dynamic earmarking game model was more stable and effective than the static earmarking game model in promoting FinTech innovation and regulation. Furthermore, when the regulators utilised a dynamic earmarking mechanism, the evolutionary path of financial institutions and regulators' behaviour strategies took the shape of a spiral and eventually converged to a central point, indicating the existence of an evolutionary stable strategy and Nash equilibrium. Finally, because the behaviour strategies of financial institutions were mainly influenced by the regulators' policies, the regulators were inspired to adjust the corresponding regulation policies on FinTech innovation.

This study bridges the knowledge gap in the existing literature on financial innovation and regulation, in particular by establishing evolutionary game models from the perspective of financial earmarking policies. Also, the case study for simulation experiments can gain a more intuitive insight into FinTech innovation and financial earmarking policies.

An alliance portfolio can help latecomer firms to acquire the necessary knowledge and resources to catch up with market leaders. However, how latecomer firms construct an alliance portfolio in terms of the nature of windows of opportunity has not been fully analyzed. This paper aims to explore how latecomer firms can build appropriate coalitions according to the nature of the window of opportunity to achieve technological catch-up in different catch-up phases.

Based on a longitudinal case study from 1984 to 2018 of Sunny Group, now a leading manufacturer of integrated optical components and products, this paper explores the process of technological catch-up of latecomer firms building different types of alliance portfolio in different windows of opportunity.

This paper finds that there is a sequence when latecomers build an alliance portfolio in the process of catch-up. When the uncertainty of opportunity increases, the governance mechanism of the alliance portfolio will change from contractual to equity-based. Also, latecomer firms build market-dominated and technology-dominated alliance portfolios to overcome their market and technology disadvantages, respectively.

These conclusions not only enrich the theory of latecomer catch-up from the perspective of windows of opportunity but also expand research on alliance portfolio processes from a temporal perspective.

The purpose of the paper is to present a three-dimensional model and analyze the internal link between surface potential distribution and the electrical activity of lumbar muscles with finite element method.

Finite element method.

The simulated results have shown that there is a significant difference of surface potential topography patterns between low back pain (LBP) patients and normal healthy control. The normal shows symmetrical in contrast with the asymmetrical LBP pattern.

It provides a new view to analyze lumbar muscle activity with finite element method, which has a potential clinical application on lumbar muscle function analysis and LBP rehabilitation assessment.

The purpose of this paper is to improve the problem of kinematics incompatibility of human–exoskeleton in the existing rigid lower-limb exoskeleton (LLE).

In this paper, following an introduction, the motion characteristics of the human knee joint and the design method of the exoskeleton were introduced. A kinematics model of the LLE based on cross-four-bar linkage was obtained. The structural parameters of the LLE mechanism were optimized by the particle swarm optimization algorithm. The predefined trajectories used in the optimization process were derived from the ankle joint, not the instantaneous center of rotation of the knee joint. Finally, the motion deviation of the optimization result was simulated, and the human–exoskeleton coordination experiment was designed to compare with the traditional single-axis knee joint in terms of comfort and coordination.

The lower limb exoskeleton mechanism obtained in this paper has a good tracking effect on human movement and has been improved in terms of comfort and coordination compared with the traditional single-axis knee joint.

The customized exoskeleton design method introduced in this paper is relatively simple, and the obtained exoskeleton has better movement coordination than the traditional exoskeleton. It can provide a reference for the design of lower limb exoskeleton and lower limb orthosis.