Zhang Shuhong and Chen Mianyun
The purpose of this paper is to select the main impact factors of environment change automatically and identify and analyze the potential environmental impact factors with time…
Abstract
Purpose
The purpose of this paper is to select the main impact factors of environment change automatically and identify and analyze the potential environmental impact factors with time delay by computer simulation, analyzing the impact rate of environmental impact factors. Then, the environmental impact factors analysis decision support system based on self‐organizing data mining model is designed.
Design/methodology/approach
Applying data mining methods in the analysis and decision making of regional environmental impact factors will have broad perspective. Self‐organization data mining is a new modeling method of complex systems modeling with strong modeling capability. It was first presented by A.G. Ivakhnenko, based on the principle of self‐organization of biological cybernetics and Kolmogoorov‐Gabor polynomial function. In this paper, the impact factors of regional environment quality evolution based on self‐organization data mining method is studied, selecting the main impact factors of environment change automatically by computer simulation, analyzing the impact contribution rate of environmental impact factors.
Findings
The environmental impact factors analysis decision support system based on self‐organizing data mining model is designed.
Research limitations/implications
Accessibility and availability of data are the main limitations affecting which model will be applied.
Practical implications
The paper has important theoretical and practical significance for the sustainable development of regional environment, resource, economy system and the constitution of environmental protection and management measures.
Originality/value
This paper not only exploits new application domains of self‐organization data mining, but also explores new ways for regional environment impact factors analysis.
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Shuhong Zhang and Mianyun Chen
The system with partial unknown structure, parameters and characteristics is called a grey system. Grey system theory is a newly developed theory to deal with the problem of…
Abstract
The system with partial unknown structure, parameters and characteristics is called a grey system. Grey system theory is a newly developed theory to deal with the problem of uncertainties in the case with “poor” information and has widely been used in many fields. The grey prediction SCGM(1,1) model has been used widely. In this paper, the characteristics of SCGM(1,1) model are systematically studied. Some new existing forms of SCGM(1,1) are derived including exponential form, α, β parameter form, scale form and recursive form. The parameter range suitable for SCGM(1,1) modeling has been studied based on strict proof. The prohibited area and the area not suitable or suitable for modeling of SCGM(1,1) model are divided clearly according to the developing coefficient a. Then, the discrete form of developing coefficient a is given. Based on the discrete form of developing coefficient a, a new grey modeling method avoiding complex matrix calculation is presented.
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This case reviews the development of Dianping. After seeing Zagat's unique business model in the United States, founder Zhang Tao found that he could bring it to China and bring…
Abstract
This case reviews the development of Dianping. After seeing Zagat's unique business model in the United States, founder Zhang Tao found that he could bring it to China and bring about local innovation. At the beginning of its establishment, the collection and promotion of comment content was the major challenge for Dianping. At the same time, Dianping faced legal issues. To solve these problems, the review mechanism of Dianping was designed to a certain extent to ensure the fairness of the review. With the advent of the mobile Internet era, Dianping began to develop a new business model. Relying on its high-quality “word-of-mouth” content and mass basis, Dianping launched group buying, online restaurant ordering, and other businesses. Dianping has always been open to strategic partners. Since 2015, Dianping has undergone historical changes, merging with Meituan. Since then, Dianping has continuously adjusted its business and organizational structure to maintain its competitiveness. Gradually, Dianping has changed from an independent business entity into a business unit of Meituan.
Dongsheng Yuan, Zhonggang Yin, Shuhong Wang, Nana Duan and Yanqing Zhang
This paper aims to propose a novel multiple transient modeling scheme for the 12-pulse phase-shifting reactor (PSR) rectifier to enhance the efficiency of full-cycle design…
Abstract
Purpose
This paper aims to propose a novel multiple transient modeling scheme for the 12-pulse phase-shifting reactor (PSR) rectifier to enhance the efficiency of full-cycle design evaluation.
Design/methodology/approach
The detailed time-domain method is adopted to model the rectifier at the behavioral layer. The diode bridges/transformer model at the architecture layer is established by using the switch function and Park transformation. The frequency domain model at the functional layer is derived with the time-varying Fourier decomposition and frequency-shifting. At the component layer, the magneto-thermal characteristics of the rectifier are analyzed with field-circuit and magnetic-thermal coupling methods. A computer-aided design program integrating multiple modeling is also developed for industrial product design.
Findings
The function layer modeling is preferred in the initial design stage, making up for the lack of modeling accuracy at the architectural layer and the lack of modeling rapidity at the behavioral layer. The component modeling is irreplaceable for the detailed evaluation in the latter design stage. The multiple modeling scheme based on the four-layer modeling helps the designers achieve high-quality products with a short development cycle.
Originality/value
The singular transient modeling cannot cover the needs of different stages in the full-cycle design evaluation. This paper fills this gap with a novel multiple modeling scheme. Meanwhile, the proposed multiple modeling scheme and developed computer-aided design program provide a great convenience for full cycle design evaluation of the 12-pulse PSR rectifier.
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Xianhai Pang, Haijun Zhang, Shuhong Wang and Hao Jing
The purpose of this paper is to study the saturation and nonlinear performance of magnetic field in the air gap of switched reluctance motor (SRM).
Abstract
Purpose
The purpose of this paper is to study the saturation and nonlinear performance of magnetic field in the air gap of switched reluctance motor (SRM).
Design/methodology/approach
The analytical method of sub-domain combined with the saturation compensation method is used to determine the nonlinear distribution of air gap magnetic field in SRM. Also, the resolutions of the two-dimensional (2D) Laplace’s equation and Poisson’s equation in polar coordinates are used to obtain the simplified expression of magnetic flux density.
Findings
For verifying the effectiveness of analytical model, the results are compared with those obtained from the 2D finite element method (FEM). The influence of magnetic saturation is taken into account by associating the sub-domain analysis result with the nonlinear B-H properties of stator and rotor iron. The magnetic flux density in radial and tangential direction considering the saturation effect may be calculated accurately. It can be seen that one can easily determine the linear analytical results accurately, whereas it is difficult to determine the magnetic flux density with saturation influence; especially at some local positions, there is a larger difference between analytical and FE model due to the complex boundary conditions.
Practical implications
This paper presents the development and optimization design of high-performance SRM.
Originality/value
The magnetic saturation may be taken into account for the SRM and analytical models support to simulated system performance.
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Shuhong Liu, Shengcai Li, Liang Zhang and Yulin Wu
The purpose of this paper is to provide a mixture model with modified mass transfer expression for calculating cavitating (two‐phase) flow.
Abstract
Purpose
The purpose of this paper is to provide a mixture model with modified mass transfer expression for calculating cavitating (two‐phase) flow.
Design/methodology/approach
The mass transfer relations are derived based on the mechanics of evaporation and condensation, in which the mass and momentum transfer count for factors such as non‐dissolved gas, turbulence, surface tension, phase‐change rate, etc.
Findings
As shown by two calculation examples, the modified model can predict the cavitating flow with high accuracy, agreeing well with experimental results.
Originality/value
The methods described are of value in improving stability in numerical calculations.
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Technical progress is an important technique within improving China’s comparative advantages, as new and renewable technologies will be beneficial for energy security. Productive…
Abstract
Purpose
Technical progress is an important technique within improving China’s comparative advantages, as new and renewable technologies will be beneficial for energy security. Productive technical progress and green technical innovation are necessary to improve working conditions and productivity of industries. Therefore, the purpose of this paper is to study technical progress in China under such harsh competitive circumstances, as well as types of technical progress that can be promoted, productive technical progress or green technology progress, and how technical progress will affect China’s competitive advantages.
Design/methodology/approach
The authors perform a multi-index multi-factor constitutive model based on a sample of 468 Chinese industries, and divide the industries into four categories.
Findings
The results indicate that there is a “U”-shape relationship between green technology progress and comparative advantages and an inverted “U”-shape relationship between the intensity of market competition and comparative advantages.
Research limitations/implications
China has crossed the inflection point of the “U”-shaped curve. This, coupled with the slowing of economic growth, demonstrates the need for advocating green technology in China to decrease the pollutant discharge. Establishing Chinese national brands within overseas markets and earning a profit through the downstream of production chain enhance China’s international competitiveness.
Originality/value
One of the most original findings of this paper points out that China is faced with a situation in which exports are severely decreased and domestic environment pollution is increased. Vigorous promotion of green technology progress, improvement of the quality and the technical content of exported products, the establishment of national brand within the overseas market, as well as enhancement of China’s international competitiveness, is needed.
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Zhigao Wang, Shuhong Wang, Jie Qiu, Weizhi Gong and Jingyin Zhang
Saturated core type superconducting fault current limiter (SFCL) can effectively limit the short-circuit current in power system. However, the high induced voltage will occur…
Abstract
Purpose
Saturated core type superconducting fault current limiter (SFCL) can effectively limit the short-circuit current in power system. However, the high induced voltage will occur between the terminals of DC superconducting bias winding caused by the variation of magnetic flux linked by DC winding due to the increasing short-circuit current. The DC source may be damaged. Thus, the induced voltage should be considered in DC winding design. The paper aims to discuss these issues.
Design/methodology/approach
Three-dimensional finite element method coupled with electric circuit.
Findings
The short-circuit current flowing through AC windings and induced voltage of DC winding are analyzed by using three-dimensional finite element method coupled with electric circuit for a 220-kV three-phase SFCL. Several circuit elements, such as a capacitor connected with DC winding in parallel, an additional short-circuit winding wound around DC core column and an energy-released piezoresistor, are, respectively, used for induced voltage reduction. These methods aim to save magnetic coupled energy in DC winding, or oppose the variation of magnetic flux, or limit the voltage of DC winding by using a resistor with low resistance.
Originality/value
The different methods for reduction of induced voltage of superconducting DC winding are studied and discussed. The decreased induced voltage may benefit the safety of superconducting DC winding and the source.
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Shuhong Kong and M. Peter van der Hoek
The rapid growth of Chinese tax revenues in the past decade is often considered “unnatural” relative to GDP growth. In this paper we investigate this seemingly unnatural growth by…
Abstract
The rapid growth of Chinese tax revenues in the past decade is often considered “unnatural” relative to GDP growth. In this paper we investigate this seemingly unnatural growth by presenting different models of the relationship between the annual growth of tax receipts and GDP. The models show different results. We also analyze various factors related to the transition from a centrally planned economy to a market economy, in particular the biased GDP calculation method, changes of the economic structure, tax policy changes and reinforcement of the tax administration. If we eliminate the impact of these factors we find that the growth of Chinese tax revenues is not unnatural, but by and large in line with the growth of GDP.
Shuhong Wang, Lu Xing and Hanxue Chen
Recently, China has been paying increasing attention to how to improve the efficiency of the marine environment and realize a green and sustainable development of the marine…
Abstract
Purpose
Recently, China has been paying increasing attention to how to improve the efficiency of the marine environment and realize a green and sustainable development of the marine economy. Consequently, the industrial structure is crucial to improving efficiency. The purpose of this paper is to introduce environmental factors into the efficiency analysis framework and explore the relationship between marine industrial structure and marine environmental efficiency.
Design/methodology/approach
This paper uses marine economic data under the DEA-BBC model to measure the marine environmental efficiency of provinces and cities and classifies them by cluster analysis. Then, the marine industrial structure and marine environmental efficiency are studied by an econometric model with human capital, ownership structure, land economic development level, scientific research input and government intervention degree as control variables.
Findings
The overall level of marine environmental efficiency is relatively low in China, increasing and then decreasing over the research period. The rationalization of industrial structure and scientific research input have significant promoting effects on marine environmental efficiency, while the degree of government intervention has a significant inhibiting effect. The positive effect of human capital on efficiency depends on whether it can be successfully converted into productivity. The effects of industrial structure advancement, ownership structure and land economic development level of on the marine environmental efficiency are mixed.
Originality/value
The results provide a theoretical and decision-making basis for China to transform and upgrade its marine industrial structure and sustainably develop the marine economy.