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Article
Publication date: 10 June 2020

Ewan Wright and Haitao Wei

The worldwide expansion of higher education participation has destabilised the value of higher education as a currency of opportunity. An increasing number of graduates are…

428

Abstract

Purpose

The worldwide expansion of higher education participation has destabilised the value of higher education as a currency of opportunity. An increasing number of graduates are experiencing the precarity of unemployment, under-employment and low salaries. This study aimed to investigate how university students in China understand and respond to the changing relationship between higher education and career opportunities.

Design/methodology/approach

The research team conducted 100 in-depth interviews with final-year undergraduates at one elite and one lower-tier university in a metropolitan city in Guangdong Province.

Findings

The students were acutely aware of fierce competition in the graduate labour market. When asked “what matters most” for post-graduation career prospects, they identified elite universities and high-status fields of study as “traditional” currencies of opportunity. Nonetheless, to stand out in a competitive environment, they perceived a growing need to supplement higher education credentials through university experiences (internships, student governance, study abroad programmes), party membership, personal connections and (overseas) postgraduate education. Moreover, in a “race to the top”, they discussed how qualitatively distinctive university experiences and elite postgraduate education are “new” currencies of opportunity for high-status professional employment.

Originality/value

The study demonstrates how intensified competition for graduate employment can result in an “opportunity trap”. The students were participating in an “arms race” to accumulate positional advantages for their post-graduation careers. The net impact of such efforts on a systemic level is to create an upward spiral in what students are expected to do in preparation for their post-graduation careers and further destabilise the value of higher education as a currency of opportunity.

Details

Asian Education and Development Studies, vol. 11 no. 1
Type: Research Article
ISSN: 2046-3162

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Article
Publication date: 10 August 2018

Yongliang Jin, Haitao Duan, Lei Wei, Song Chen, Xuzheng Qian, Dan Jia and Jian Li

This paper aims to investigate the tribological behavior and online infrared spectra of three types of lubricating oils containing dinonyl diphenylamine (DNDA) antioxidant, which…

155

Abstract

Purpose

This paper aims to investigate the tribological behavior and online infrared spectra of three types of lubricating oils containing dinonyl diphenylamine (DNDA) antioxidant, which are mineral oil (MO), poly alpha olefin (PAO) and trimethylolpropane trioleate (TMPTO), during the friction process at high temperature (temperature rising at first and isothermal holding afterwards).

Design/methodology/approach

A platform of low speed four-ball tribometer equipped with a temperature controller combined with infrared spectrometer was established. MO, PAO and TMPTO base oils were mixed with 1.0 Wt.% DNDA antioxidant, coded as MOa, PAOa and TMPTOa in sequence. The friction coefficient and online infrared spectra of the oils were tested during the friction process of temperature rising at first and isothermal holding afterwards, and the wear tracks of the upper balls were measured using a confocal scanning optical microscope.

Findings

The results indicated that the DNDA antioxidant was depleted to reduce the generation of alcohols and carbonyl products, and the depletion rate of DNDA followed the sequence of MOa > PAOa > TMPTOa. In the temperature rising friction process, the critical transition of friction coefficient was confirmed. The addition of DNDA antioxidant reduced the temperature of the oils at the critical transition of friction coefficient, and the temperature followed the sequence of TMPTOa > PAOa > MOa. After the critical transition, the friction coefficient was first increased and then declined to a steady value; the friction coefficient of MOa increased and declined first, followed by PAOa and TMPTOa. In the steady stage of friction, there was no obvious effect of DNDA on the friction coefficient of the oils. Moreover, DNDA enhanced the wear properties of MOa and PAOa; no obvious improvement was revealed for the wear property of TMPTOa.

Originality/value

The established platform of low speed four-ball tribometer combined with infrared spectrometer successfully realized online testing of the structure changes of lubricating oil during high temperature friction, which can give some reference on the oxidation and friction researches of lubricating oil.

Details

Industrial Lubrication and Tribology, vol. 70 no. 7
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 14 December 2017

Hongwang Du, Wei Xiong, Haitao Wang and Zuwen Wang

In this study, a modeling method for a clamped deformable cable simulation based on Kirchhoff theory is proposed. This methodology can be used to describe the physical deformation…

291

Abstract

Purpose

In this study, a modeling method for a clamped deformable cable simulation based on Kirchhoff theory is proposed. This methodology can be used to describe the physical deformation configuration of any constrained flexible cable in a computer-aided design/manufacturing system. The modeling method, solution algorithm, simulation and experimental results are presented to prove the feasibility of the proposed methodology. The paper aims to discuss these issues.

Design/methodology/approach

First, Kirchhoff equations for deformable cables are proposed based on the nonlinear mechanics of thin elastic rods, and the general solution of the equations described by the Euler angles is given in the arc coordinate system. The parametric form solution of the Kirchhoff equations, which is easy to use, is then obtained in a cylindrical coordinate form based on Saint Venant’s theory. Finally, mathematical expressions that reflect the clamped cable configuration are given, and the deformable process is simulated based on an open source geometry kernel and is then tested by a 3D laser scanning technology.

Findings

The method presented in this paper can be adapted to any boundary condition for constrained cables as long as the external force and torque are known. The experimental results indicate that both the model and algorithm are efficient and accurate.

Research limitations/implications

A more comprehensive study must be executed for the physical simulation of more complicated constrained cables, such as the helical spring and asymmetric constraint. The influence of the material properties of the cable on the calculation efficiency must be considered in future analysis.

Originality/value

The semi-analytical algorithm of the cable simulation in cylindrical coordinates is a novel topic and is more accurate and efficient than the common numerical solution.

Details

Assembly Automation, vol. 38 no. 1
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 4 November 2019

Du Hongwang, Wei Xiong, Wang Haitao and Wang Zuwen

In this paper, a novel and unified method for geometry configuration simulation of flexible cable under certain boundary conditions is presented. This methodology can be used to…

201

Abstract

Purpose

In this paper, a novel and unified method for geometry configuration simulation of flexible cable under certain boundary conditions is presented. This methodology can be used to realize cable assembly verification in any computer-aided design/manufacturing system. The modeling method, solution algorithm, geometry configuration simulation and experimental results are presented to prove the feasibility of this proposed methodology. The paper aims to discuss these issues.

Design/methodology/approach

Considering the gravity, bending and torsion, modeling of cable follows the Kirchhoff theory. For this purpose, Euler quaternions are used to describe its spatial geometry configuration by a carefully chosen set of coordinates. Then the cable is discretized by the FEM, and the equilibrium condition per element is computed. In this way, the global static behavior is independent of the discretization. The static evolution of the cable is obtained by numerical integration of the resulting Kirchhoff equations. Then the manner is demonstrated, in which this system of equations can be decoupled and efficiently solved. Geometry configuration simulation examples with different boundary conditions are presented. Finally, experiment validation are given to describe the effectiveness of the models and algorithms.

Findings

The method presented in this paper can be adapted to computer-aided assembly verification of flexible cable. The experimental results indicate that both of the model and algorithm are efficient and accurate.

Research limitations/implications

The method should be extended to flexible cables with multiple branches and more complex constraints (holes, curved surfaces and clamps) and non-circular sections. Dynamic assembly process simulation based on the Kirchhoff theory must be considered in the future.

Originality/value

Unlike in previous approaches, the cable behavior was independent of the underlying discretization, and the finite element approach enables physically plausible cable assembly verification.

Details

Assembly Automation, vol. 40 no. 6
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 18 January 2024

Zaihua Luo, Juliang Xiao, Sijiang Liu, Mingli Wang, Wei Zhao and Haitao Liu

This paper aims to propose a dynamic parameter identification method based on sensitivity analysis for the 5-degree of freedom (DOF) hybrid robots, to solve the problems of too…

205

Abstract

Purpose

This paper aims to propose a dynamic parameter identification method based on sensitivity analysis for the 5-degree of freedom (DOF) hybrid robots, to solve the problems of too many identification parameters, complex model, difficult convergence of optimization algorithms and easy-to-fall into a locally optimal solution, and improve the efficiency and accuracy of dynamic parameter identification.

Design/methodology/approach

First, the dynamic parameter identification model of the 5-DOF hybrid robot was established based on the principle of virtual work. Then, the sensitivity of the parameters to be identified is analyzed by Sobol’s sensitivity method and verified by simulation. Finally, an identification strategy based on sensitivity analysis was designed, experiments were carried out on the real robot and the results were verified.

Findings

Compared with the traditional full-parameter identification method, the dynamic parameter identification method based on sensitivity analysis proposed in this paper converges faster when optimized using the genetic algorithm, and the identified dynamic model has higher prediction accuracy for joint drive forces and torques than the full-parameter identification models.

Originality/value

This work analyzes the sensitivity of the parameters to be identified in the dynamic parameter identification model for the first time. Then a parameter identification method is proposed based on the results of the sensitivity analysis, which can effectively reduce the parameters to be identified, simplify the identification model, accelerate the convergence of the optimization algorithm and improve the prediction accuracy of the identified model for the joint driving forces and torques.

Details

Industrial Robot: the international journal of robotics research and application, vol. 51 no. 2
Type: Research Article
ISSN: 0143-991X

Keywords

Available. Open Access. Open Access
Article
Publication date: 13 September 2022

Haitao Ding, Wei Li, Nan Xu and Jianwei Zhang

This study aims to propose an enhanced eco-driving strategy based on reinforcement learning (RL) to alleviate the mileage anxiety of electric vehicles (EVs) in the connected…

1167

Abstract

Purpose

This study aims to propose an enhanced eco-driving strategy based on reinforcement learning (RL) to alleviate the mileage anxiety of electric vehicles (EVs) in the connected environment.

Design/methodology/approach

In this paper, an enhanced eco-driving control strategy based on an advanced RL algorithm in hybrid action space (EEDC-HRL) is proposed for connected EVs. The EEDC-HRL simultaneously controls longitudinal velocity and lateral lane-changing maneuvers to achieve more potential eco-driving. Moreover, this study redesigns an all-purpose and efficient-training reward function with the aim to achieve energy-saving on the premise of ensuring other driving performance.

Findings

To illustrate the performance for the EEDC-HRL, the controlled EV was trained and tested in various traffic flow states. The experimental results demonstrate that the proposed technique can effectively improve energy efficiency, without sacrificing travel efficiency, comfort, safety and lane-changing performance in different traffic flow states.

Originality/value

In light of the aforementioned discussion, the contributions of this paper are two-fold. An enhanced eco-driving strategy based an advanced RL algorithm in hybrid action space (EEDC-HRL) is proposed to jointly optimize longitudinal velocity and lateral lane-changing for connected EVs. A full-scale reward function consisting of multiple sub-rewards with a safety control constraint is redesigned to achieve eco-driving while ensuring other driving performance.

Details

Journal of Intelligent and Connected Vehicles, vol. 5 no. 3
Type: Research Article
ISSN: 2399-9802

Keywords

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Article
Publication date: 27 July 2021

Xinwang Li, Juliang Xiao, Wei Zhao, Haitao Liu and Guodong Wang

As complex analysis of contact models is required in the traditional assembly strategy, it is still a challenge for a robot to complete the multiple peg-in-hole assembly tasks…

520

Abstract

Purpose

As complex analysis of contact models is required in the traditional assembly strategy, it is still a challenge for a robot to complete the multiple peg-in-hole assembly tasks autonomously. This paper aims to enable the robot to complete the assembly tasks autonomously and more efficiently, with the strategies learned by reinforcement learning (RL), a learning-accelerated deep deterministic policy gradient (LADDPG) algorithm is proposed.

Design/methodology/approach

The multiple peg-in-hole assembly strategy is designed in two modules: an advanced planning module and a bottom control module. The advanced module is completed by the LADDPG agent, which is used to derive advanced commands based on geometric and environmental constraints, that is, the desired contact force. The bottom-level control module will drive the robot to complete the compliant assembly task through the adaptive impedance algorithm according to the command set issued by the advanced module. In addition, a set of safety assurance mechanisms is developed to safely train a collaborative robot to complete autonomous learning.

Findings

The method can complete the assembly tasks well through RL, and it can realize satisfactory compliance of the robot to the environment. Compared with the original DDPG algorithm, the average values of the instantaneous maximum contact force and contact torque during the assembly process are reduced by approximately 38% and 74%, respectively.

Practical implications

The entire algorithm can also be applied to other robots and the assembly strategy can be applied in the field of the automatic assembly.

Originality/value

A compliant assembly strategy based on the LADDPG algorithm is proposed to complete the automated multiple peg-in-hole assembly tasks.

Details

Industrial Robot: the international journal of robotics research and application, vol. 49 no. 1
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 4 November 2019

Hongwang Du, Wei Xiong, Haitao Wang and Zuwen Wang

Cables are widely used, and they play a key role in complex electromechanical products such as vehicles, ships, aircraft and satellites. Cable design and assembly significantly…

376

Abstract

Purpose

Cables are widely used, and they play a key role in complex electromechanical products such as vehicles, ships, aircraft and satellites. Cable design and assembly significantly impact the development cycle and assembly quality, which is be-coming a key element affecting the function of a product. However, there are various kinds of cables, with complex geo-metric configurations and a narrow assembly space, which can easily result in improper or missed assembly, an unreasonable layout or interference. Traditional serial design methods are inefficient and costly, and they cannot predict problems in installation and use. Based on physical modeling, computer-aided cable design and assembly can effectively solve these problems. This paper aims to address virtual assembly (VA) of flexible cables based on physical modeling.

Design/methodology/approach

Much research has focused recently on virtual design and assembly-process planning for cables. This paper systematically reviews the research progress and the current state of mechanical models, virtual design, assembly-process planning, collision detection and geometric configuration and proposes areas for further research.

Findings

In the first instance, the main research groups and typical systems are investigated, followed by extensive exploration of the major research issues. The latter can be reviewed from five perspectives: the current state of mechanical models, virtual design, assembly-process planning, collision detection and geometric configuration. Finally, the barriers that prevent successful application of VA are also discussed, and the future research directions are summarized.

Originality/value

This paper presents a comprehensive survey of the topics of VA of flexible cables based on physical modeling and investigates some new ideas and recent advances in the area.

Details

Assembly Automation, vol. 40 no. 2
Type: Research Article
ISSN: 0144-5154

Keywords

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Article
Publication date: 29 November 2024

Haitao Xiong, Wei Jiao and Yuanyuan Cai

The occurrence and dissemination of hate videos in social media platform could pose serious harm to both society and individuals. However, the characteristics of the hate videos…

23

Abstract

Purpose

The occurrence and dissemination of hate videos in social media platform could pose serious harm to both society and individuals. However, the characteristics of the hate videos increase the difficulty of detection task. Hate content is usually presented in a relatively covert manner in videos, and textual content in videos plays an important role in hate video detection. In this work, we propose a textual context enhanced dynamic bimodal fusion (TCE-DBF) method for hate video detection.

Design/methodology/approach

The proposed method TCE-DBF introduces dynamic modality gate (DMG) and bimodal fusion transformer network to dynamically integrate multimodalities. Moreover, in order to enhance textual modality in videos, two types of textual context from the video are taken as the input of TCE-DBF. One is extracted from video frames in visual modality. The other is extracted from audio in acoustic modality. Specially, TCE-DBF splits the original audio and learns the sequence representation to capture acoustic temporal information.

Findings

Hate video detection has been one of the hotspots in recent works. However, it still faces two serious challenges. The first challenge is the hate content in videos presented in multimodalities. The second challenge is how to evaluate the importance of different modalities for multimodal fusion modeling. TCE-DBF aims to tackle these challenges. Experimental results on hate video dataset HateMM demonstrate that TCE-DBF outperforms the state-of-the-art methods, and the visualization results show that textual modality plays a more important role in hate video detection. Therefore, it is vital to consider the text in videos.

Originality/value

TCE-DBF can be utilized to effectively detect hate videos on social media. Besides transcript, TCE-DBF considers text in video frames, which makes detection more accurate. Meanwhile, to better achieve multimodal fusion, TCE-DBF uses DMG and bimodal fusion transformer network to dynamically assign different weights to three modalities and integrate them. The proposed TCE-DBF is novel in terms of capturing multimodal features, enhancing the textual modality and achieving high detection performance for hate video detection.

Details

Data Technologies and Applications, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2514-9288

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Article
Publication date: 11 September 2024

Pengkun Cheng, Juliang Xiao, Wei Zhao, Yangyang Zhang, Haitao Liu and Xianlei Shan

This paper aims to enhance the machining accuracy of hybrid robots by treating the moving platform as the first joint of a serial robot for direct position measurement and…

62

Abstract

Purpose

This paper aims to enhance the machining accuracy of hybrid robots by treating the moving platform as the first joint of a serial robot for direct position measurement and integrating external grating sensors with motor encoders for real-time error compensation.

Design/methodology/approach

Initially, a spherical coordinate system is established using one linear and two circular grating sensors. This system enables direct acquisition of the moving platform’s position in the hybrid robot. Subsequently, during the coarse interpolation stage, the motor command for the next interpolation point is dynamically updated using error data from external grating sensors and motor encoders. Finally, fuzzy proportional integral derivative (PID) control is applied to maintain robot stability post-compensation.

Findings

Experiments were conducted on the TriMule-600 hybrid robot. The results indicate that the following errors of the five grating sensors are reduced by 94%, 93%, 80%, 75% and 88% respectively, after compensation. Using the fourth drive joint as an example, it was verified that fuzzy adaptive PID control performs better than traditional PID control.

Practical implications

The proposed online error compensation strategy significantly enhances the positional accuracy of the robot end, thereby improving the actual processing quality of the workpiece.

Social implications

This method presents a technique for achieving online error compensation in hybrid robots, which promotes the advancement of the manufacturing industry.

Originality/value

This paper proposes a cost-effective and practical method for online error compensation in hybrid robots using grating sensors, which contributes to the advancement of hybrid robot technology.

Details

Industrial Robot: the international journal of robotics research and application, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0143-991X

Keywords

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