Search results

1 – 10 of over 1000
Article
Publication date: 16 January 2017

Ye Chen and Zhelong Wang

Existing studies on human activity recognition using inertial sensors mainly discuss single activities. However, human activities are rather concurrent. A person could be walking…

Abstract

Purpose

Existing studies on human activity recognition using inertial sensors mainly discuss single activities. However, human activities are rather concurrent. A person could be walking while brushing their teeth or lying while making a call. The purpose of this paper is to explore an effective way to recognize concurrent activities.

Design/methodology/approach

Concurrent activities usually involve behaviors from different parts of the body, which are mainly dominated by the lower limbs and upper body. For this reason, a hierarchical method based on artificial neural networks (ANNs) is proposed to classify them. At the lower level, the state of the lower limbs to which a concurrent activity belongs is firstly recognized by means of one ANN using simple features. Then, the upper-level systems further distinguish between the upper limb movements and infer specific concurrent activity using features processed by the principle component analysis.

Findings

An experiment is conducted to collect realistic data from five sensor nodes placed on subjects’ wrist, arm, thigh, ankle and chest. Experimental results indicate that the proposed hierarchical method can distinguish between 14 concurrent activities with a high classification rate of 92.6 per cent, which significantly outperforms the single-level recognition method.

Practical implications

In the future, the research may play an important role in many ways such as daily behavior monitoring, smart assisted living, postoperative rehabilitation and eldercare support.

Originality/value

To provide more accurate information on people’s behaviors, human concurrent activities are discussed and effectively recognized by using a hierarchical method.

Article
Publication date: 19 June 2017

Zhelong Wang and Ye Chen

In sensor-based activity recognition, most of the previous studies focused on single activities such as body posture, ambulation and simple daily activities. Few works have been…

Abstract

Purpose

In sensor-based activity recognition, most of the previous studies focused on single activities such as body posture, ambulation and simple daily activities. Few works have been done to analyze complex concurrent activities. The purpose of this paper is to use a statistical modeling approach to classify them.

Design/methodology/approach

In this study, the recognition problem of concurrent activities is explored with the framework of parallel hidden Markov model (PHMM), where two basic HMMs are used to model the upper limb movements and lower limb states, respectively. Statistical time-domain and frequency-domain features are extracted, and then processed by the principal component analysis method for classification. To recognize specific concurrent activities, PHMM merges the information (by combining probabilities) from both channels to make the final decision.

Findings

Four studies are investigated to validate the effectiveness of the proposed method. The results show that PHMM can classify 12 daily concurrent activities with an average recognition rate of 93.2 per cent, which is superior to regular HMM and several single-frame classification approaches.

Originality/value

A statistical modeling approach based on PHMM is investigated, and it proved to be effective in concurrent activity recognition. This might provide more accurate feedback on people’s behaviors.

Practical implications

The research may be significant in the field of pervasive healthcare, supporting a variety of practical applications such as elderly care, ambient assisted living and remote monitoring.

Article
Publication date: 1 July 2024

Qianqian Shi, Longyu Yao, Changwei Bi and Jianbo Zhu

The construction of megaprojects often involves substantial risks. While insurance plays an important role as a traditional risk transfer means, owners and insurance companies may…

Abstract

Purpose

The construction of megaprojects often involves substantial risks. While insurance plays an important role as a traditional risk transfer means, owners and insurance companies may still suffer huge losses during the risk management process. Therefore, considering the strong motivation of insurance companies to participate in the on-site risk management of megaprojects, this study aims to propose a collaborative incentive mechanism involving insurance companies, to optimize the risk management effect and reduce the risk of accidents in megaprojects.

Design/methodology/approach

Based on principal-agent theory, the research develops the static and dynamic incentive models for risk management in megaprojects, involving both the owner and insurance company. The study examines the primary factors influencing incentive efficiency. The results are numerically simulated with a validation case. Finally, the impact of parameter changes on the stakeholders' benefits is analyzed.

Findings

The results indicate that the dynamic incentive model is available to the achievement of a flexible mechanism to ensure the benefits of contractors while protecting the benefits of the owner and insurance company. Adjusting the incentive coefficients for owners and insurance companies within a specified range promotes the growth of benefits for all parties involved. The management cost and economic benefit allocation coefficients have a positive effect on the adjustment range of the incentive coefficient, which helps implement a more flexible dynamic incentive mechanism to motivate contractors to carry out risk management to reduce risk losses.

Originality/value

This study makes up for the absence of important stakeholders in risk management. Different from traditional megaproject risk management, this model uses insurance companies as bridges to break the island effect of risk management among multiple megaprojects. This study contributes to the body of knowledge by designing appropriate dynamic incentive mechanisms in megaproject risk management through insurance company participation, and provides practical implications to both owner and insurance company on incentive contract making, thus achieving better risk governance of megaprojects.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

Keywords

Article
Publication date: 7 February 2023

Qiu Wang and Mark W. Langager

Given the less mature homeschooling ecosystem in China, together with the similarity of purpose, the current study examined the lived experiences of curricular choice making in…

Abstract

Purpose

Given the less mature homeschooling ecosystem in China, together with the similarity of purpose, the current study examined the lived experiences of curricular choice making in the USA and China and categories of respective families (homeschools), as a way of understanding curricular flexibility. In addressing these features, based on an updated model of curricular flexibility as it applies to homeschooling, the authors examined the aspects of who, what, when, where and how to see if this context offers new light. The authors then consider ways in which the model can be further updated for greater analytical clarity and accuracy. The purpose of this paper is to address these issues.

Design/methodology/approach

A descriptive case study was conducted in the Xi'an city of China and the Seattle metropolitan area of the USA. A survey and two rounds of semi-structured interview data were collected from ten homeschooling families in both contexts.

Findings

The study found families’ adjusted curricula for different motives, as they navigated differing societal contexts, and curricular flexibility in homeschooling contexts was theorized as standardization and structuring strategies and social dimensions, and family preference patterns were identified. Chinese homeschooling families had comparatively less variety of available resources and freedom to homeschools compared to American counterparts, and they operated with the awareness of a standard national curriculum and its social implications.

Originality/value

This study elaborates on a little-discussed topic – the overall curriculum of each homeschool and motives influencing changing curricular choices during the process of homeschooling. And it is the first paper to use the model to explicitly define curricular flexibility in the homeschooling context, thus extending the existing theoretical discussion of curricular flexibility.

Details

International Journal of Comparative Education and Development, vol. 25 no. 1
Type: Research Article
ISSN: 2396-7404

Keywords

Article
Publication date: 13 March 2020

Zhiqiang Xie, Lei Wang, Zhengyang Zhu, Zhi Fu and Xingdong Lv

The purpose of this paper is to introduce an interval finite element method (IFEM) to simulate the temperature field of mass concrete under multiple influence uncertainties e.g…

Abstract

Purpose

The purpose of this paper is to introduce an interval finite element method (IFEM) to simulate the temperature field of mass concrete under multiple influence uncertainties e.g. environmental temperature, material properties, pouring construction and pipe cooling.

Design/methodology/approach

Uncertainties of the significant factors such as the ambient temperature, the adiabatic temperature rise, the placing temperature and the pipe cooling are comprehensively studied and represented as the interval numbers. Then, an IFEM equation is derived and a method for obtaining interval results based on monotonicity is also presented. To verify the proposed method, a non-adiabatic temperature rise test was carried out and subsequently simulated with the method. An excellent agreement is achieved between the simulation results and the monitoring data.

Findings

An IFEM method is proposed and a non-adiabatic temperature rise test is simulated to verify the method. The interval results are discussed and compared with monitoring data. The proposed method is found to be feasible and effective.

Originality/value

Compared with the traditional finite element methods, the proposed method taking the uncertainty of various factors into account and it will be helpful for engineers to gain a better understanding of the real condition.

Details

Engineering Computations, vol. 37 no. 7
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 12 August 2014

Shunchong Li, Xinjun Sheng, Honghai Liu and Xiangyang Zhu

This paper aims to describe the design of a multi-degree of freedom (DOF) prosthetic hand prototype implementing postural synergy mechanically, which is actuated by two motors via…

Abstract

Purpose

This paper aims to describe the design of a multi-degree of freedom (DOF) prosthetic hand prototype implementing postural synergy mechanically, which is actuated by two motors via a transmission unit, and is controlled using surface electromyography (sEMG) signal.

Design/methodology/approach

First, an anthropomorphic robotic hand is designed to imitate the human hand. The robotic hand has 18 DOF, 12 of which are actively driven by Bowden cables. Next, a set of different grasp modes are performed on a “full actuation” robotic hand, and principal component analysis (PCA) method is used to extract the first two postural synergies. Then, they are used to design a differential pulley-based transmission unit using two independent inputs to drive 12 output tendons. Finally, two control signals extracted from six channels of sEMG signals are used to proportionally control the two motors for achieving hand posture synthesis.

Findings

Using a differential pulley-based mechanical transmission unit to implement the synthesis of the first two postural synergies can make the prosthetic hand achieve different grasps by two motors, such as power, precision and lateral grasps. It is also feasible to control this “two actuation” prosthetic hand by relating the two-dimensional sEMG inputs with the first two postural synergies.

Originality/value

Mechanical implantation of postural synergies reduces the number of independent actuators without sacrificing the prosthetic hand’s versatility and simplifies its controller. Two-dimensional control extracted from sEMG is mapped into the combination coefficients of postural synergy synthesis. It shows potential application in the practical prosthetic hand.

Details

Industrial Robot: An International Journal, vol. 41 no. 5
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 26 February 2010

Sheng Zhu and Yongjiang Shi

The purpose of this paper is to explore an indigenous innovation phenomenon – entitled the Shanzhai phenomenon – which has emerged in the Chinese mobile phone industry, and to…

5675

Abstract

Purpose

The purpose of this paper is to explore an indigenous innovation phenomenon – entitled the Shanzhai phenomenon – which has emerged in the Chinese mobile phone industry, and to understand its value creation network and operational mechanism, as well as to recognize its policy implications in regional and industrial developments.

Design/methodology/approach

Although the Shanzhai phenomenon emerged from the end of 2008, detailed understanding of its systems and operational mechanism is still very limited, partly because of its secrecy and dynamics in the value chain operations. Based on characteristics of the Shaizhai phenomenon, the paper focuses on three levels of the phenomenon – regional historical, regional industrial specific, and typical Shanzhai mobile phone project levels – to pursue a comprehensive understanding of the Shanzhai system and its emerging environments. At the regional and industrial level, the combined approaches of interview and secondary data collection is adopted. At the Shanzhai project level, a case study approach is conducted by focusing on the project and its whole value chain, from the idea creation towards detailed product design, production and integration, as well as its distribution.

Findings

Chinese government has called for indigenous innovation to upgrade Chinese manufacturing capability and value creation as well as appropriation. Based on the fast growth of the Chinese indigenous mobile phone industry in the last two years, the Shanzhai manufacturing system is recognized as a new positive alternative way for Chinese manufacturing companies to achieve this aim. Behind the Shanzhai phenomenon, there is a strong globally specialized and collaborated network enabling the down‐stream Chinese small‐ and medium‐sized mobile phone companies to very quickly respond to customers' demands or lead the demands. This new type of alternative innovation system is transforming unaffordable luxury goods into affordable for normal consumers. Because of its mass volume and involvement, however, government policies to harness the energy and development direction become essential.

Research limitations/implications

This research is just a very early stage of preliminary observation. From the methodology perspective, it provides background information about Shanzhai phenomenon and an in‐depth case study about a Shanzhai project. Comprehensive understandings of the Shanzhai phenomenon in terms of its behaviours, systems constructs and patterns, trajectories in the future and implications for policies will be achieved only at a much later date.

Practical implications

ShanZhai manufacturing might be one possible alternative innovative paradigm in some sectors of China.

Originality/value

This is the first academic research paper to offer relatively comprehensive and systematic observations about the emerging ShanZhai manufacturing system in the largest developing country.

Details

Journal of Science and Technology Policy in China, vol. 1 no. 1
Type: Research Article
ISSN: 1758-552X

Keywords

Open Access
Article
Publication date: 31 October 2023

Hongping Xing, Yu Liu and Xiaodan Sun

The smoothness of the high-speed railway (HSR) on the bridge may exceed the allowable standard when an earthquake causes vibrations for HSR bridges, which may threaten the safety…

Abstract

Purpose

The smoothness of the high-speed railway (HSR) on the bridge may exceed the allowable standard when an earthquake causes vibrations for HSR bridges, which may threaten the safety of running trains. Indeed, few studies have evaluated the exceeding probability of rail displacement exceeding the allowable standard. The purposes of this article are to provide a method for investigating the exceeding probability of the rail displacement of HSRs under seismic excitation and to calculate the exceeding probability.

Design/methodology/approach

In order to investigate the exceeding probability of the rail displacement under different seismic excitations, the workflow of analyzing the smoothness of the rail based on incremental dynamic analysis (IDA) is proposed, and the intensity measure and limit state for the exceeding probability analysis of HSRs are defined. Then a finite element model (FEM) of an assumed HSR track-bridge system is constructed, which comprises a five-span simply-supported girder bridge supporting a finite length CRTS II ballastless track. Under different seismic excitations, the seismic displacement response of the rail is calculated; the character of the rail displacement is analyzed; and the exceeding probability of the rail vertical displacement exceeding the allowable standard (2mm) is investigated.

Findings

The results show that: (1) The bridge-abutment joint position may form a step-like under seismic excitation, threatening the running safety of high-speed trains under seismic excitations, and the rail displacements at mid-span positions are bigger than that at other positions on the bridge. (2) The exceeding probability of rail displacement is up to about 44% when PGA = 0.01g, which is the level-five risk probability and can be described as 'very likely to happen'. (3) The exceeding probability of the rail at the mid-span positions is bigger than that above other positions of the bridge, and the mid-span positions of the track-bridge system above the bridge may be the most hazardous area for the running safety of trains under seismic excitation when high-speed trains run on bridges.

Originality/value

The work extends the seismic hazardous analysis of HSRs and would lead to a better understanding of the exceeding probability for the rail of HSRs under seismic excitations and better references for the alert of the HSR operation.

Content available
Article
Publication date: 24 February 2012

354

Abstract

Details

Journal of Science and Technology Policy in China, vol. 3 no. 1
Type: Research Article
ISSN: 1758-552X

Keywords

Content available
Article
Publication date: 26 February 2010

Jiang Yu and John Adams

441

Abstract

Details

Journal of Science and Technology Policy in China, vol. 1 no. 1
Type: Research Article
ISSN: 1758-552X

1 – 10 of over 1000