Abstract
Purpose
This study aims to improve the force sensing performance of the robot joint for the safety and flexibility of physical human–robot interaction.
Design/methodology/approach
A force sensing mechanism (FSM) for an S-shaped spring of a robot variable stiffness actuator (VSA) was designed. The yield strength of the spring material, geometric and assembly structure constraints of the VSA are all considered for the actuator deflection limit design. The elastic deformation model is solved in reverse to obtain the local deformation limit profile of the S-spring at different spring angles. The deformation limit mechanism is manufactured by three-dimensional printing and assembled with S-springs. The force sensing function for the VSA is achieved by the input and output shaft encoders and stiffness model. The FSM is verified by torque-deflection experiments with variable stiffness.
Findings
The yield strength of the S-spring material is the strictest constraint for elastic deformation. Experimental results show that the external force can be quickly and reliably perceived. As the spring angle increases (stiffness increases), the hysteresis and nonlinear error decrease. Under the constraint of the FSM, the maximum deflection also decreases rapidly.
Originality/value
The designed FSM based on the deformation and stiffness model provides a comprehensive design reference in a VSA with nonlinear elastic mechanisms, which is ignored but important for exploring the VSAs potential.
Details
Keywords
Xiwen Cai, Haobo Qiu, Liang Gao, Xiaoke Li and Xinyu Shao
This paper aims to propose hybrid global optimization based on multiple metamodels for improving the efficiency of global optimization.
Abstract
Purpose
This paper aims to propose hybrid global optimization based on multiple metamodels for improving the efficiency of global optimization.
Design/methodology/approach
The method has fully utilized the information provided by different metamodels in the optimization process. It not only imparts the expected improvement criterion of kriging into other metamodels but also intelligently selects appropriate metamodeling techniques to guide the search direction, thus making the search process very efficient. Besides, the corresponding local search strategies are also put forward to further improve the optimizing efficiency.
Findings
To validate the method, it is tested by several numerical benchmark problems and applied in two engineering design optimization problems. Moreover, an overall comparison between the proposed method and several other typical global optimization methods has been made. Results show that the global optimization efficiency of the proposed method is higher than that of the other methods for most situations.
Originality/value
The proposed method sufficiently utilizes multiple metamodels in the optimizing process. Thus, good optimizing results are obtained, showing great applicability in engineering design optimization problems which involve costly simulations.
Details
Keywords
Xiaoke Li, Haobo Qiu, Zhenzhong Chen, Liang Gao and Xinyu Shao
Kriging model has been widely adopted to reduce the high computational costs of simulations in Reliability-based design optimization (RBDO). To construct the Kriging model…
Abstract
Purpose
Kriging model has been widely adopted to reduce the high computational costs of simulations in Reliability-based design optimization (RBDO). To construct the Kriging model accurately and efficiently in the region of significance, a local sampling method with variable radius (LSVR) is proposed. The paper aims to discuss these issues.
Design/methodology/approach
In LSVR, the sequential sampling points are mainly selected within the local region around the current design point. The size of the local region is adaptively defined according to the target reliability and the nonlinearity of the probabilistic constraint. Every probabilistic constraint has its own local region instead of all constraints sharing one local region. In the local sampling region, the points located on the constraint boundary and the points with high uncertainty are considered simultaneously.
Findings
The computational capability of the proposed method is demonstrated using two mathematical problems, a reducer design and a box girder design of a super heavy machine tool. The comparison results show that the proposed method is very efficient and accurate.
Originality/value
The main contribution of this paper lies in: a new local sampling region computational criterion is proposed for Kriging. The originality of this paper is using expected feasible function (EFF) criterion and the shortest distance to the existing sample points instead of the other types of sequential sampling criterion to deal with the low efficiency problem.
Details
Keywords
Chen Kuilin, Feng Xi, Fu Yingchun, Liu Liang, Feng Wennan, Jiang Minggang, Hu Yi and Tang Xiaoke
The data protection is always a vital problem in the network era. High-speed cryptographic chip is an important part to ensure data security in information interaction. This paper…
Abstract
Purpose
The data protection is always a vital problem in the network era. High-speed cryptographic chip is an important part to ensure data security in information interaction. This paper aims to provide a new peripheral component interconnect express (PCIe) encryption card solution with high performance, high integration and low cost.
Design/methodology/approach
This work proposes a System on Chip architecture scheme of high-speed cryptographic chip for PCIe encryption card. It integrated CPU, direct memory access, the national and international cipher algorithm (data encryption standard/3 data encryption standard, Rivest–Shamir–Adleman, HASH, SM1, SM2, SM3, SM4, SM7), PCIe and other communication interfaces with advanced extensible interface-advanced high-performance bus three-level bus architecture.
Findings
This paper presents a high-speed cryptographic chip that integrates several high-speed parallel processing algorithm units. The test results of post-silicon sample shows that the high-speed cryptographic chip can achieve Gbps-level speed. That means only one single chip can fully meet the requirements of cryptographic operation performance for most cryptographic applications.
Practical implications
The typical application in this work is PCIe encryption card. Besides server’s applications, it can also be applied in terminal products such as high-definition video encryption, security gateway, secure routing, cloud terminal devices and industrial real-time monitoring system, which require high performance on data encryption.
Social implications
It can be well applied on many other fields such as power, banking, insurance, transportation and e-commerce.
Originality/value
Compared with the current strategy of high-speed encryption card, which mostly uses hardware field-programmable gate arrays or several low-speed algorithm chips through parallel processing in one printed circuit board, this work has provided a new PCIe encryption card solution with high performance, high integration and low cost only in one chip.
Details
Keywords
Xinyu Guo, Xu Chen and Xiaoke Liang
The purpose of this paper is to explore the impact and mechanism of WeChat public platforms articles (abbreviated as WPP) on blood donation behavior using data of WPPA and…
Abstract
Purpose
The purpose of this paper is to explore the impact and mechanism of WeChat public platforms articles (abbreviated as WPP) on blood donation behavior using data of WPPA and donation behavior data.
Design/methodology/approach
This paper uses multiple linear regression methods, web crawlers and natural language processing technology. It first quantifies the impact of WPP published articles on donation behavior. On this basis, it then selects data from the day of article publication to further study the impact of article dissemination on donation behavior from the perspective of reading quantity, and analyzes the influencing factors of article reading quantity.
Findings
The results show that on the same day that an article is published, there is an increase of 13.8 and 14.3% in blood donation volume and fan registrations, respectively. The mediating effect exists. However, the day after an article is published, there is no longer any effect on blood donations. With a 1% increase in reading quantity, blood donation volume on the day of article publication increases by 0.13%, and this positive impact is promoted by the quality of the articles. A conc ise articles title and body and rich images help drive reading quantity. Moreover, blood donors prefer to read articles about blood dynamics and donation promotion, while articles about news, announcements and administrative affairs make them less inclined to read.
Originality/value
First, it focuses on WPPA, quantifies the impact of articles on blood donation behavior and analyzes the mechanism. Second, the authors study the impact and timeliness of social media article dissemination to address the insufficiency of existing research. Third, the study provides a scientific basis for the editing and publishing of articles, helping blood banks improve the effectiveness of publicity and recruitment.
Details
Keywords
Xu Han, Zhonghe Han, Wei Zeng, Peng Li and Jiangbo Qian
The purpose of this paper is to study the condensation flow of wet steam in the last stage of a steam turbine and to obtain the distribution of condensation parameters such as…
Abstract
Purpose
The purpose of this paper is to study the condensation flow of wet steam in the last stage of a steam turbine and to obtain the distribution of condensation parameters such as nucleation rate, Mach number and wetness.
Design/methodology/approach
Because of the sensitivity of the condensation parameter distribution, a double fluid numerical model and a realizable k-ε-kd turbulence model were applied in this study, and the numerical solution for the non-equilibrium condensation flow is provided.
Findings
The simulation results are consistent with the experimental results of the Bakhtar test. The calculation results indicate that the degree of departure from saturation has a significant impact on the wet steam transonic condensation flow. When the inlet steam deviates from the saturation state, shock wave interference and vortex mixing also have a great influence on the distribution of water droplets.
Originality/value
The research results can provide reference for steam turbine wetness losses evaluation and flow passage structure optimization design.
Details
Keywords
This study aims to investigate the influence and impact mechanism of capital tax incentives on firm innovation.
Abstract
Purpose
This study aims to investigate the influence and impact mechanism of capital tax incentives on firm innovation.
Design/methodology/approach
This study employs the difference-in-differences (DID) method, in conjunction with the exogenous impact of accelerated depreciation (AD) pilot policy. This study selects Chinese listed companies from 2010 to 2017 as the research sample.
Findings
Firstly, AD exerts a substantial positive effect on the quantity and quality of the innovation output of firms, and the positive impact results primarily from heightened investment in fixed assets, particularly, machinery and equipment. Secondly, the influence of the policy is pronounced in non-state-owned enterprises, mature enterprises, less capital-intensive enterprises and non-high-tech industries, which all exhibit strong innovation incentives. Lastly, the tax incentive policy significantly stimulates firm innovation in the short term, but its long-term impact on innovation incentives lacks statistical significance.
Originality/value
This study highlights the significance of capital tax incentives in facilitating the innovation process in firms.
Details
Keywords
Xing Yan and Yaping Chang
Microblog has become an important tool of social marketing since 2010. Compared with traditional blog, microblog has several distinctive features, such as ease of use, viral…
Abstract
Purpose
Microblog has become an important tool of social marketing since 2010. Compared with traditional blog, microblog has several distinctive features, such as ease of use, viral transmission, high interactivity and real-time communication. Microblog provides a communication platform for companies and consumers; however, it challenges companies’ consumer-brand relationship management. The purpose of this paper is to investigate the influencing mechanism of microblog interaction tactics on consumer-brand relationship.
Design/methodology/approach
Based on grounded theory, 66 representative companies’ posts on Weibo are collected, with 1,395 company posts and 5,959 following posts. An influence mechanism model of company microblog interaction tactics on consumer-brand relationship is proposed, then the saturation level of this mechanism is tested.
Findings
Results show that: first, companies adopt two types of tactics in microblog interaction: social interaction and task-oriented interaction; second, microblog interaction arises consumers’ emotional response and cognition toward specific brand and eventually influences consumer-brand relationship. Consumers’ emotional response includes pleasure and arousal, brand cognition includes perceived quality, perceived relatedness with companies and brand resonance; third, the influence mechanism differs among different consumer knowledge level, industry and brand awareness.
Practical implications
This study provides insight into the use of microblog interaction tactics. Companies may cross-use social interaction and task-oriented interaction tactics to enhance consumer-brand relationship. Companies need to produce microblog content based on the interests of consumers and further establish and improve fan feedback mechanism.
Originality/value
This paper constructs a model of the influence of company microblog interaction tactics on consumers. This study finds that co-creation activities initiated by companies are the new tactics to attract consumers on microblog. The finding adds new knowledge to the literature of company consumer interaction and provides a theoretical basis for the practice of microblog marketing.
Details
Keywords
Asad Ullah Khan, Zhiqiang Zhang, Milad Taleby Ahvanooey and Wajid Rafique
Blockchain technology is a distributed and decentralized public digital ledger, which is employed to save dynamic transaction data and static records across several computers so…
Abstract
Purpose
Blockchain technology is a distributed and decentralized public digital ledger, which is employed to save dynamic transaction data and static records across several computers so that each record could not be modified retroactively without the collusion of the network and alteration of all subsequent blocks. Recently, it has become immensely popular in digital resource sharing in different research areas such as healthcare, smart cities, cryptocurrency and libraries. Since the current eLibrary systems are vulnerable to issues such as unauthorized access, plagiarism, etc., there is a lack of access control system that can efficiently address these issues.
Design/methodology/approach
The authors designed a conceptual model for evaluating the users' intention in the use of blockchain-based digital libraries, which can facilitate the resource organization and provide additional security to interactive processes between users. To conduct our survey, the authors devised and shared two versions, English and Chinese, among 298 participants. Moreover, 7 PhD students participated in the pre-testing of the questioner design. The authors analyzed the demographic data using the Jamovi software and SmartPLS in order to generate the path modeling.
Findings
This study revealed that blockchain technology adaption in eLibraries is essential for enhancing the quality of services, infrastructure and resources for libraries. The study’s results show that optimism, informativeness, perceived usefulness, perceived ease of use, attitude and intention to use blockchain technology for accessing digital resources in libraries.
Originality/value
This study contributes to the adoption of blockchain technology in the digital library. To the best of the authors’ knowledge, this work is the first empirical attempt to provide a new perspective of developing digital libraries based on security policies. This model shows the underpinning knowledge to manage digital resources, which can facilitate the design phases and enhance the management costs in eLibraries.
Details
Keywords
Nour el Imane Harrat, Sabrine Louala, Fatima Bensalah, Fouad Affane, Hadjera Chekkal and Myriem Lamri-Senhadji
The purpose of this study was to investigate the effects of prickly pear (Opuntia ficus indica (OFI)) nopalitos on body weight, food consumption, arterial blood pressure, glucidic…
Abstract
Purpose
The purpose of this study was to investigate the effects of prickly pear (Opuntia ficus indica (OFI)) nopalitos on body weight, food consumption, arterial blood pressure, glucidic homeostasis, cholesterol metabolic pathway and tissues redox status in type 2 diabetic (T2D) rats fed a high-fat diet (HFD).
Design/methodology/approach
Rats were fed by a HFD containing 30 per cent sheep fat for 10 weeks, after which they were rendered diabetic by an injection of a low dose of streptozotocin (STZ) (35 mg/kg). The diabetic rats were then divided into two groups. The first group consumed the HFD supplemented with 5 per cent (g/100 g diet) of freeze-dried OFI nopalitos (HFD-OFI), and the second group received the HFD without supplementation (HFD).
Findings
OFI nopalitos treatment decreased significantly arterial diastolic (−20%; p = 0.0001) and systolic (−16%; p = 0.0001) pressures, glycemia (−14%; p = 0.03), insulinemia (−50%; p = 0.04), glycated hemoglobin (−49%; p = 0.003), homeostasis model assessment insulin resistance (−67%; p = 0.03), cholesterolemia (−31%; p = 0.003), very-low and low-density lipoprotein cholesterol (−38%; p = 0.002 and −63% p = 0.0002, respectively); thiobarbituric acid reactive substances and lipid hydroperoxide contents, respectively, in liver (−26% p = 0.02, −20% p = 0.02), adipose tissue (−30% p = 0.002, −25% p = 0.001), muscle (−29% p = 0.003, −25% p = 0.008) and kidney (lipid hydroperoxides only (−28%; p = 0.001) but increased high-density lipoprotein (HDL2) cholesteryl esters (+61%; p = 0.0001), serum lecithin: cholesterol acyltransferase activity (+21%; p = 0.006) and antioxidant enzymes activities (superoxide dismutase, glutathione peroxidase and catalase) of some tissues (liver, adipose tissue, muscle and kidney).
Originality/value
Freeze-dried OFI nopalitos improves arterial blood pressure, glycemic control, metabolic pathway of cholesterol and redox status in T2D rats.