Many analysis and design problems in engineering and science involve uncertainty to varying degrees. This paper is concerned with the structural vibration problem involving…
Abstract
Purpose
Many analysis and design problems in engineering and science involve uncertainty to varying degrees. This paper is concerned with the structural vibration problem involving uncertain material or geometric parameters, specified as fuzzy parameters. The requirement is to propagate the parameter uncertainty to the eigenvalues of the structure, specified as fuzzy eigenvalues. However, the usual approach is to transform the fuzzy problem into several interval eigenvalue problems by using the α-cuts method. Solving the interval problem as a generalized interval eigenvalue problem in interval mathematics will produce conservative bounds on the eigenvalues. The purpose of this paper is to investigate strategies to efficiently solve the fuzzy eigenvalue problem.
Design/methodology/approach
Based on the fundamental perturbation principle and vertex theory, an efficient perturbation method is proposed, that gives the exact extrema of the first-order deviation of the structural eigenvalue. The fuzzy eigenvalue approach has also been improved by reusing the interval analysis results from previous α-cuts.
Findings
The proposed method was demonstrated on a simple cantilever beam with a pinned support, and produced very accurate fuzzy eigenvalues. The approach was also demonstrated on the model of a highway bridge with a large number of degrees of freedom.
Originality/value
This proposed Vertex-Perturbation method is more efficient than the standard perturbation method, and more general than interval arithmetic methods requiring the non-negative decomposition of the mass and stiffness matrices. The new increment method produces highly accurate solutions, even when the membership function for the fuzzy eigenvalues is complex.
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Ye Li, Xue Bai, Bin Liu and Yuying Yang
In order to accurately forecast nonlinear and complex characteristics of solar power generation in China, a novel discrete grey model with time-delayed power term (abbreviated as
Abstract
Purpose
In order to accurately forecast nonlinear and complex characteristics of solar power generation in China, a novel discrete grey model with time-delayed power term (abbreviated as
Design/methodology/approach
Firstly, the time response function is deduced by using mathematical induction, which overcomes the defects of the traditional grey model. Then, the genetic algorithm is employed to determine the optimal nonlinear parameter to improve the flexibility and adaptability of the model. Finally, two real cases of installed solar capacity forecasting are given to verify the proposed model, showing its remarkable superiority over seven existing grey models.
Findings
Given the reliability and superiority of the model, the model
Practical implications
This paper provides a scientific and efficient method for forecasting solar power generation in China with nonlinear and complex characteristics. The forecast results can provide data support for government departments to formulate solar industry development policies.
Originality/value
The main contribution of this paper is to propose a novel discrete grey model with time-delayed power term, which can handle nonlinear and complex time series more effectively. In addition, the genetic algorithm is employed to search for optimal parameters, which improves the prediction accuracy of the model.
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The suppliers of experimental resources required in megaprojects are driven by short-term interests, presuming that participation in the digital platform would only increase their…
Abstract
Purpose
The suppliers of experimental resources required in megaprojects are driven by short-term interests, presuming that participation in the digital platform would only increase their inputs and fail to rapidly expand their revenue, resulting in their insufficient motivation to participate. This paper aims to design effective incentives for these suppliers exhibiting the aforementioned behaviour to drive them to participate and actively share their resources on the platform.
Design/methodology/approach
This paper develops incentives for applying the digital platform for experimental resource sharing by using a reverse induction approach to model and solve an incomplete information game. It compares the traditional experiment management mode and the new mode of applying the digital platform, taking the degree of sharing experimental resources on the platform as the variable and constructing three incentive models. By analysing these different degrees of sharing and the different experimental and informatisation capabilities of the suppliers, it could obtain the optimal incentive scheme for changes in sharing behaviour.
Findings
The results show that the designed incentives could increase the participation of suppliers in the platform and the number of their shared resources and make the benefits of both the supplier and the demand side reach the optimal state of a win-win situation. However, a higher degree of sharing by suppliers does not yield better results. In addition, the incentive coefficients for this degree should be set based on the suppliers’ different experimental and informatisation capabilities and the ratio of input cost-sharing, so as to avoid blind inputs from both supply and demand.
Originality/value
This study fills the research gap regarding incentives of the digital platform of experimental resource-sharing for megaprojects; it contributes to the body of knowledge by providing a quantitative perspective of understanding the experimental resource-sharing behaviour that motivates the usage of the digital platform. Furthermore, it reveals the incentive mechanism for application in different scenarios, and quantitative analysis is conducted to provide practical insights into promoting the new experiment management mode in megaprojects for more effective incentivisation.
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Wanjuan Zhong and Lisa Catherine Ehrich
The purpose of this paper is to explore two dimensions of leadership practices (i.e. teaching and learning and sources of power) used by two exemplary principals in mainland China…
Abstract
Purpose
The purpose of this paper is to explore two dimensions of leadership practices (i.e. teaching and learning and sources of power) used by two exemplary principals in mainland China against a background of education reform and to identify how broader contextual factors have shaped these two dimensions of their leadership.
Design/methodology/approach
An exploratory case study was used that drew upon semi‐structured interviews, observations and document analysis. Interviews were conducted with two principals, six teachers from each of the two schools and a superintendent who was the supervisor of the two principals.
Findings
The findings reveal that there are some common elements in both of the leaders' practices but also some subtle differences. Both leaders emphasise teaching and learning. One sees herself as curriculum expert; the other delegate teaching responsibilities. While both uses a top down approach, one principal uses an adversarial approach and the other a more facilitative approach.
Research limitations/implications
The study used a small sample size. It explored the leaders' practices in the light of broader contextual factors rather than personal factors or gender‐based factors
Originality/value
Given the limited empirical research conducted on female principals in mainland China, this qualitative study provides insights into two dimensions of leadership used by two exemplary principals and explains their practices in the light of critical contextual factors such as contemporary and traditional Chinese culture and the school's organisational context.
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Zhang Lixia, Tang Hong and He Miao
The purpose of this paper is to predict hospital respiratory system infection rate by using the gray GM(1,1) model, and to provide theoretical basis for the prospective study on…
Abstract
Purpose
The purpose of this paper is to predict hospital respiratory system infection rate by using the gray GM(1,1) model, and to provide theoretical basis for the prospective study on hospital respiratory system infection management.
Design/methodology/approach
The annual respiratory system infection rate of a comprehensive third-class hospital in Yan’an is collected from 2011 to 2017. The GM(1,1) model is used for prediction, and mean absolute percentage error is used to evaluate the prediction accuracy of the model.
Findings
GM(1,1) statistical prediction model is established with good fitting degree and high reliability of extrapolation prediction.
Originality/value
The GM(1,1) model can well predict the respiratory system infection rate of the hospital.
Details
Keywords
Zeng Huawei, Wang Chengtao, Qiao Jie, Zhang Bingjing, Zhao Bing and Dai Chuangyun
The Monascus pigment has been widely applied in the food processing industry as a functional additive. Lovastatin and polysaccharides are two important bio-active materials found…
Abstract
Purpose
The Monascus pigment has been widely applied in the food processing industry as a functional additive. Lovastatin and polysaccharides are two important bio-active materials found in Monascus. Citrinin is considered as mycotoxin. Thus, it is important to produce high yields of intracellular Monascus pigments with high yields of lovastatin and polysaccharides, while maintaining low citrinin yields under liquid fermentation.
Design/methodology/approach
The intracellular yields of pigments, lovastatin, polysaccharides and citrinin; biomass; and reducing the sugar content of Monascus purpureus HBSD 08 were determined every day during a 10-day culturing period using lactose, maltose, sucrose, glucose, glycerine and xylose as the sole carbon sources. Additionally, the pigment composition was analysed by a thin layer chromatography (TLC) and the in vitro antitumor activities of the pigments were determined.
Findings
The maximal yield of pigments (55.44 U/mL after six days of culture) and lovastatin content (1,475.30 µg/L after five days of culture) were obtained in the presence of glucose and maltose as the sole carbon sources, respectively. The suitable carbon sources for high intracellular polysaccharides yields were sucrose, maltose and xylose. Glucose should not be chosen as the sole carbon source because of its high food safety risk. In vitro antitumor activities of pigments in the presence of different carbon sources were in the order of xylose > glucose = maltose > glycerine > sucrose = lactose. The pigment compositions in the presence of different carbon sources were the same from the TLC analysis. Thus, maltose displayed high intracellular yields of pigments, lovastatin and polysaccharides; high food safety against citrinin, and high in vitro antitumor activity during the ten days culturing period.
Originality/value
This study shows us the benefits of using maltose as a substrate in the production of intracellular Monascus pigments while ensuring economic and food safety.
Details
Keywords
Lihua Li, Maria Estela Varua, Adam M. Komarek, Sriram Shankar and William D. Bellotti
The purpose of this paper is to explore the endogenous relationship between production specialisation and market commercialisation with an empirical study of farmers in Northwest…
Abstract
Purpose
The purpose of this paper is to explore the endogenous relationship between production specialisation and market commercialisation with an empirical study of farmers in Northwest China.
Design/methodology/approach
The three-stage least squares were used to address simultaneity and over-identification problems in comparison with two-stage least squares (2SLS). The Durbin-Wu-Hausman test was employed to identify the endogeneity of the commercialisation and specialisation variables. The validity, relevance, and strength of the instruments were tested using the Stock-Yogo weak instrument diagnostics test.
Findings
A two-way interrelationship between specialisation and commercialisation were confirmed, and suggest that farmers’ decisions on farm commercialisation and production specialisation are actually separate and interacting.
Social implications
By demonstrating that a virtuous cycle exists between agricultural commercialisation and on-farm specialisation, policies can be formulated to complement these two effects that may help increase small holders’ income. Farmers’ market participation can be indirectly improved by combining market improvement and risk management tools to encourage production specialisation.
Originality/value
The insights of this study cast further light onto the farm market participation theory by emphasising that higher asset endowments enable small farmers to specialise in production with comparative advantage.