Search results

Domestic demand for walnuts has been on the rise for the last decades. Consumption outstrips domestic production capacities, which led to increasing prices until recently. Small-scale farmers are at the centre of walnut tree planting and walnut collection efforts. Farmers are now integrated into rapidly expanding agrifood value chains. The purpose of this paper is to investigate the walnut value chain originating in Yunnan (the dominant producer of walnuts in China). The authors are especially interested in the position of small-scale farmers in the chain and the factors affecting the price that they receive.

Price and intra-chain governance information were collected through structured interviews with value chain actors like certified and conventional small-scale farmers, traders, processors, food manufacturers and wholesalers. The resultant price data set was analysed using a multiple regression analysis.

Timing of harvest, distance to market and sales volume are correlated with the village-level price. Farmers are in a market governance segment of the chain. Lead firms (e.g. supermarkets) are price-setters and determine the value distribution, with farmers receiving a smaller share relative to downstream actors’ shares.

Improved connectivity to markets, transparency of standards and price (formation), processing and certification could improve farmers’ profits.

The authors contribute to the growing literature of value chain studies focussing on farmers’ integration into food systems at different scales. The authors investigated the price determinants at the village level and additionally provide information on an organic marketing arrangement.

Aerospace assembly demands high drilling position accuracy for fastener holes. Hole position error correction is a key issue to meet the required hole position accuracy. This paper aims to propose a combined hole position error correction method to achieve high positioning accuracy.

The bilinear interpolation surface function based on the shape of the aerospace structure is capable of dealing with position error of non-gravity deformation. A gravity deformation model is developed based on mechanics theory to efficiently correct deformation error caused by gravity. Moreover, three solution strategies of the average, least-squares and genetic optimization algorithms are used to solve the coefficients in the gravity deformation model to further improve position accuracy and efficiency.

Experimental validation shows that the combined position error correction method proposed in this paper significantly reduces the position errors of fastener holes from 1.106 to 0.123 mm. The total position error is reduced by 43.49% compared with the traditional mechanics theory method.

The position error correlation method could reach an accuracy of millimeter or submillimeter scale, which may not satisfy higher precision.

The proposed position error correction method has been integrated into the automatic drilling machine to ensure the drilling position accuracy.

The proposed position error method could promote the wide application of automatic drilling and riveting machining system in aerospace industry.

A combined position error correction method and the complete roadmap for error compensation are proposed. The position accuracy of fastener holes is reduced stably below 0.2 mm, which can fulfill the requirements of aero-structural assembly.

Technological innovation and the flexibilisation of labour markets have expanded the pool of workers engaged in globally distributed work. This paper aims to propose an analytical framework to understand and support the productive professional learning of those engaged in global work. Drawing on the theory of expansive learning in the cultural-historical activity theory tradition the study aims to stimulate and enrich the conceptual notion of work as a learning space in the discussion of workplace learning particularly in global work.

Iteration between theory and data is applied to identify the dimensions of expansion for the configuration of learning spaces in global work. Data are drawn from the experiences of 10 professionals selected by purposive sampling in Austria, Italy, the Netherlands and Singapore.

Six dimensions of expansion are identified as challenging and potentially empowering for professionals’ configuration of learning spaces in global work: social-spatial, material-instrumental, moral-ethical, political-economic, personal-professional and temporal-developmental.

The conceptual framework for the dimensions of expansion of learning spaces provides the broad strokes for reflexive curricula that democratise the learning and development of professionals in global work, who are currently underserved given the national orientation of vocational education and training and professional development ecosystems.

In China, external supervision on construction safety mainly comes from the government and supervision engineers (SEs). However, the construction safety supervisory mechanism (CSSM) contains some dilemmas affecting the improvement of safety performance, such as the declining impact of SEs, the increasing rent-seeking behaviors of contractor and excessive government interference. This study aims to depict and analyze the CSSM in China from an evolutionary game view. The objectives are to understand the supervision strategy and evolutionary behaviors of different stakeholders, propose suggestions for improving safety performance and help the key safety supervision stakeholders, especially the government, formulate a suitable safety supervision strategy.

This research uses tripartite dynamic evolutionary game theory to study the CSSM in China and solve the stable equilibrium solution using system dynamics.

This study has revealed the game relationship of construction safety supervision mechanisms in China and solved the stable equilibrium solution. The results prove that a supervision engineer (SE) plays a crucial role in the CSSM, and “supervision engineer useless” is an unreasonable assertion. For government supervision agency (GSA), excessive inspection and free-market regulation are neither wise strategies. GSA can reduce the inspection frequency when general contractors (GCs) input high safety investments and SEs implement responsible supervision. But keeping proper government supervision to avoid GC's unlawful behaviors and SE's rent-seeking is indispensable. In addition, excessive governmental supervision will weaken SE's role, so the government should transfer some supervision powers to SE.

This study focuses on the dynamic evolution process between GSA, GC and SE. This method is different from most research that neglected the dynamic characteristic of system and game solution stability. The research methods not only contribute to construction safety supervision policy-making in China but also help to improve supervision efficiency in other countries and other fields.

Aircraft assembly demands high position accuracy of drilled fastener holes. Automated drilling is a key technology to fulfill the requirement. The purpose of the paper is to conduct positioning variation analysis and control for an automated drilling to achieve a high positioning accuracy.

The nominal and varied connective models of automated drilling are constructed for positioning variation analysis regarding automated drilling. The principle of a strategy for reducing positioning variation in drilling, which shortens the positioning variation chain with the aid of an industrial camera-based vision system, is explored. Moreover, other strategies for positioning variation control are developed based on mathematical analysis to further reduce the position errors of the drilled fastener holes.

The propagation and accumulation of an automated drilling system’s positioning variation are explored. The principle of reducing positioning variation in an automated drilling using a monocular vision system is discussed from the view of variation chain.

The strategies for reducing positioning variation, rooted in the constructed positioning variation models, have been applied to a machine-tool based automated drilling system. The system is developed for a wing assembly of an aircraft in the Aviation Industry Corporation of China.

Propagation, accumulation and control of positioning variation in an automated drilling are comprehensively explored. Based on this, the positioning accuracy in an automated drilling is controlled below 0.13 mm, which can meet the requirement for the assembly of the aircraft.

The purpose of this paper is to facilitate understanding of how to convert free players to paid consumers in free-to-play games.

Drawing on the consumption value framework and affordance theory, the present study argues that in-game purchase behaviors are determined by multiple consumption values of in-game items. The perceptions of consumption values were influenced by game affordances. The model was tested, using data from an empirical survey with 2,006 free-to-play game players.

Monetary, enjoyment and social values of in-game items positively predict purchase behaviors in free-to-play games. Game fairness and balance of challenges and skills significantly influence perceived enjoyment value.

The findings of this study provide operable implications to facilitate in-game consumption. The model was tested within the context of free-to-play multiplayer online battle arena (MOBA) games; however, caution is advisable when generalizing the findings to other subgenre of games.

This study extended and thus validated the consumption value framework in the context of free-to-play MOBA games. This study explored the antecedents of consumption values from the perspective of game affordance.

Wonders whether, owing to severely restricted access, China’s government policy towards digital communications will remain in a constant state of flux – or will it gain economic benefits without a social penalty? Concludes that China has to link the forces of change to channel and deflect domestic resistance.

This paper aims to investigate the changes in living standard among families with different socio-economic status in China with the use of Engel's Coefficient. The authors develop a decomposition methodology to figure out the driving forces behind changes in Engel's Coefficient, and investigate how dramatic economic growth, volatile food price and rapid nutrition transition affect living standard among different families.

The authors propose a statistical method to decompose the changes in living standard measured by Engel's Coefficient into structure effect, price effect, quantity effect and income effect. Using the China Health and Nutrition Survey data between 2000 and 2011, the authors estimate these four effects by employing a decomposition method.

Results show that Engel's Coefficient in China decreased by 8.7 percentage points (hereafter “pp”) during 2000–2011, where structure effect leads to 0.2 pp increase, price effect results in 17.7 pp increase, quantity effect brings about 12.4 pp decline and income effect contributes to 14.2 pp decline. Results indicate that rising food prices are the main obstacle to improve households' living standard. Typically, poor and rural families' living standard is more vulnerable to the rise in food prices, and they benefit less from income growth.

This study proposes a decomposition method to investigate the determinants of change in Engel's Coefficient, which provides a deeper understanding of how economic growth, food price change and nutrition transition affect people's living standard in different socio-economic groups in developing countries. This study also provides valuable insights on how to achieve common prosperity from the perspective of consumption upgrading.

The collection and use of personal medical information for mobile health (mHealth) service raise significant privacy concerns. In this context, this study aims to explore the privacy paradox and its impact from the perspective of paradox resolution.

Based on social support theory and privacy calculus theory, this study first studies the effect of social support on perceived benefits, and explores the moderating effect of perceived health status on the privacy trade-off process. Secondly, the study examines the path of “privacy concerns – disclosure intention – disclosure behavior” to verify the existence of the privacy paradox. Following this, based on rational choice theory, the rationality degree is introduced as a moderating variable to investigate both its impact on the central route and the strength of this impact on the privacy paradox.

Empirical results show that informational support and emotional support influence perceived benefits significantly. Perceived benefits significantly influence privacy concerns, and perceived health status has a significant positive moderating effect. The authors further find that there is a privacy paradox within the mHealth context, and the privacy paradox is moderated negatively by rationality degree. The findings indicate that the impact strength of the privacy paradox will decrease with increases in rationality degree.

The findings indicate that it is crucial to evaluate the privacy paradox and its impact from the perspective of paradox resolution.

This study offers a complete comprehension of the privacy paradox in mHealth and provides several valuable recommendations for enhancing both mHealth services and privacy controls.

This paper aims to propose a roadmap to control the robot–subassembly (R–S) coordination errors in movable robotic drilling. Fastener hole drilling for multi-station aircraft assembly demands a robotic drilling system with expanded working volume and high positioning accuracy. However, coordination errors often exist between the robot and the subassembly to be drilled because of disturbances.

Mechanical pre-locating and vision-based robot base frame calibration are consecutively implemented to achieve in-process robot relocation after station transfer. Thus, coordination errors induced by robotic platform movements, inconsistent thermal effects, etc. are eliminated. The two-dimensional (2D) vision system is applied to measure the remainder of the R–S coordination errors, which is used to enhance the positioning accuracy of the robot. Accurate estimation of measured positioning errors is of great significance for evaluating the positioning accuracy. For well estimation of the positioning errors with small samples, a bootstrap approach is put forward.

A roadmap for R–S coordination error control using a 2D vision system, composed of in-process relocation, coordination error measurement and drilled position correction, is developed for the movable robotic drilling.

The proposed roadmap has been integrated into a drilling system for the assembly of flight control surfaces of a transport aircraft in Aviation Industry Corporation of China. The position accuracy of the drilled fastener holes is well ensured.

A complete roadmap for controlling coordination errors and improving positioning accuracy is proposed, which makes the high accuracy and efficiency available in movable robotic drilling for aircraft manufacturing.