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Based on the inverse kinematics and task space dynamic model, this paper aims to design a high-precision trajectory tracking controller for a 2-DoF translational parallel manipulator (TPM) driven by linear motors.

The task space dynamic model of a 2-DoF TPM is derived using Lagrangian equation of the first type. A task space dynamic model-based feedforward controller (MFC) is designed, which is combined with a cascade PID/PI controller and velocity feedforward controller (VFC) to construct a hybrid PID/PI+VFC/MFC controller. The hybrid controller is implemented in MATLAB/dSPACE real-time control platform. Experiment results are given to validate the effectiveness and industrial applicability of the hybrid controller.

The MFC can compensate for the nonlinear dynamic characteristics of a 2-DoF TPM and achieve better tracking performance than the conventional acceleration feedforward controller (AFC).

The task space dynamic model-based hybrid PID/PI+VFC/MFC controller is proposed for a 2-DoF linear-motor-driven TPM, which reduces the tracking error by at least 15 percent compared with conventional hybrid PID/PI+VFC/AFC controller. This control scheme can be extended to high-speed and high-precision trajectory tracking control of other parallel manipulators by reprogramming the feedforward signals of traditional cascade PID/PI controller.

The impact of underfill properties on the thermomechanical reliability of flip chip on board (FCOB) assembly is addressed in this paper. FCOB assemblies using three underfill encapsulants were subjected to a thermal cycling test. The performance of the underfill encapsulants was assessed by a statistical analysis of the failure distribution of the FCOB assemblies. The failure modes in the thermal cycling test were found to be solder joint cracks, delamination at underfill/chip passivation interface, and underfill internal cracks. An attempt was made to correlate these failures with underfill properties such as the coefficient of thermal expansion (CTE), modulus, glass transition temperature (Tg), and adhesive strength to the chip. Additionally, nonlinear finite element analysis (FEA) was conducted to verify the experimental results.

The purpose of this paper is to explore the nonlinear analysis on the relay feedback technology (RFT) applied to parameters identification of servo mechanism.

In order to investigate nonlinear elements' influence on RFT, the analysis was conducted in the velocity and current control loops, respectively. The RFT algorithm for modeling servo mechanism with friction was developed to overcome the nonlinear influence. Furthermore, the results from experiments were presented to validate the analysis and illustrated the advantages of the proposed method.

The Coulomb friction and current changing are the main nonlinear influence on the RFT application in servo mechanism. The friction effects should be included to servo system modeling based on RFT.

Some suggestions concluded from nonlinear analysis are useful to optimize the selection of parameters in RFT. And the proposed algorithm is applicable to modeling servo mechanism with friction.

The nonlinear analysis in the different control loops of servo mechanism based on RFT is presented and the effective identification approach is proposed in this paper.

The drive shaft and the distribution shaft of a traditional radial piston pump are in a cantilever state. To solve this problem, this paper aims to present a radial piston pump with through shaft driving and valve plate distribution.

The working principle of the pump is discussed in detail. In this radial piston pump, valve plate distribution parts are designed to distribute oil to the piston chambers, and the distribution shaft is replaced. A bearing is installed between the stator and rotator to reduce the friction. The transmission shaft is supported by two bearings to ensure smooth operation. The support force of the transmission shaft is optimized. In addition, the flow pulsation principle is presented. To accomplish the change, the displacement of the radial piston pump, the proportional control system is designed.

After completing the machining and assembly of the pump, an experimental study was carried out. The results show that the output flow of the pump is basically the same as the theoretical flow.

The friction between the slipping shoes and the stator is greatly reduced due to the function of rolling bearings. The higher stability of the driveshaft is obtained for the reason of double-sided support. The radial piston pump has a novel structural design in reducing the friction between the shoes and the stator and improving the stability of the transmission shaft.

In order to solve the problem of how to reduce the service delay of edge computing, this paper proposes an edge cloud framework, which contains four groups under different locations between mobile edge nodes and users. A feasible cost scheme can be obtained by calculating the cost in different simulation groups. Furthermore, we give suggestions on how to deploy edge nodes at a reasonable cost for users effectively.

This paper is motivated by the IoT-Cloud framework; they are divided according to whether the nodes have templates required by users and the distance from users to distinguish various consumption levels and classify the testing result. Based on four different groups satisfying reasonable resource allocation, the cost was studied. The work focuses on the unpredictable movement within the test range. For assignment and scheduling of template tasks at each time slot, the Edge-Cloud scheme is proposed to reduce the cost.

According to the simulation results in this paper, the total cost of the four groups is lower when the closest node-set satisfies the user service directly. To improve the probability that the closest node-set can meet general requests of users and provide them with faster and more economical network services, increasing the number of edge nodes within the range of user activities is suggested.

An Edge-Cloud framework is constructed in four groups, and the conclusion of a feasible cost scheme came out.

In China, a major grain producer, rice losses during harvest cannot be ignored. The purpose of this paper is to assess the extent of rice harvest losses in major grain-producing areas in China by a sampling survey, and to further analyze the main factors influencing rice harvest losses using an ordered multinomial logistic model.

In this study, data were collected using a multi-stage sampling method from ten major rice-producing provinces/regions in China. On this basis, five counties were selected from each of these provinces/regions. In the actual survey, house numbers were randomly selected, and then corresponding farmer households were visited by trained investigators.

The survey found that 56.22 percent of respondents believed that rice harvest losses were 4 percent or lower in China, though there were differences among the provinces. The proportion of family business income, planting scale, mechanization level, timely harvest, and operational meticulousness had negative effects on rice harvest losses. On the other hand, farmers’ experience of employment as migrant workers had a positive effect on rice harvest losses. In addition, bad weather and short handedness during harvest significantly increased rice harvest losses.

The meaning of rice harvest losses was defined based on previous research findings on the definition of grain harvest losses and the realities in China. The current rice harvest losses in different areas in China were analyzed based on sampling survey data from 957 farmers in ten provinces in China.

This research is motivated by the increasing need for international interactions during the gradual recovery of the tourism industry. By recognizing the paucity of research on cultural closeness and accommodation categories, this research aims to illuminate the influencing mechanisms of psychological closeness and travelers’ willingness to book an accommodation-sharing property while booking an accommodation.

The authors employ a mixed-methods approach, including an experiment and semistructured interviews.

Results show that hosts’ higher cultural identity congruence leads to travelers’ higher willingness to book an accommodation-sharing property. Psychological closeness mediates the positive effect of cultural identity congruence on travelers’ willingness to book. The authors further explore the moderating role of room types (entire room vs. private room) and find that the mediation effect is stronger for booking an entire room.

The current research underlines the importance of cultural identity congruence and accommodation type on travelers’ willingness to book an accommodation-sharing property and psychological closeness.

Shifting to OLSL classes during the pandemic can bring learners ambivalent experiences: negative, positive or both appraisals toward the technologies. However, few studies have examined how ambivalent experiences can influence students' learning behaviors, specifically cyberslacking and active participation. Using the challenge-hindrance stressor framework, this study investigates the impact of challenge and hindrance appraisals on these learning behaviors.

This study uses a mixed methods approach to answer research questions. An interview was conducted to identify the key components of ambivalent appraisals, and a survey was conducted to empirically examine the impact of challenge and hindrance appraisals on learners' behaviors in online live streaming learning (OLSL) contexts. The data of 675 university students were analyzed using structural equation modeling.

This study found that hindrance appraisal leads to cyberslacking while challenge appraisal leads to active participation, but it can also cause cyberslacking. Social presence has a double-edged effect, acting as both a facilitator and inhibitor, strengthening the effect of hindrance appraisal on cyberslacking and the impact of challenge appraisal on active participation.

Prior studies have primarily focused on the negative side (techno-distress) of technology appraisals. This study simultaneously examines the positive side, techno-eustress, on learners' behaviors in OLSL contexts, and explores the moderating effects of social presence. This study contributes to the technostress and technology adaptation literature by revealing how technology-induced ambivalent appraisals impact behavioral responses. It offers important theoretical and practical implications for education tool designers.

Drawing on the knowledge-based view (KBV), the research examines the impact of knowledge sources (internal and external knowledge sources) on two aspects of innovation radical and incremental innovation. Additionally, the research seeks to provide deeper insight into the link between the variables by studying how information technology (IT) resources mediate the relationship between knowledge sources and innovation capability.

The study assessed the relationship between latent variables using a quantitative research approach and variance-based structural equation modelling on a sample of 380 individuals from 83 Pakistani manufacturing and service firms.

The study's results revealed a significant impact of knowledge sources (internal and external knowledge sources) on radical and incremental innovation. Further, the study examines the mediating role of IT resources in connecting knowledge sources and a firm's innovation capability.

Future studies should investigate the association among the constructs under the moderating roles of environmental turbulence to provide insight into the relationship between knowledge sources, IT resources, and innovation capability.

The paper provides evidence that knowledge sources and IT resources are the key driving factors of innovation capability. Managers and directors of firms in developing and emerging countries should establish firms' knowledge sources and IT resources to improve innovation capability.

There is a scarcity of studies that has explored the relationship between sources of knowledge, IT resources, and specific types of innovation, namely radical and incremental innovation. The paper helps fill research gaps in the literature and advances understanding of how knowledge sources, directly and indirectly, stimulate firms' innovation capabilities via the mediating role of IT resources.

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.

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