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The purpose of this paper is to establish the optimization model and solve the short‐term economic dispatch of cascaded hydro‐plants.
Abstract
Purpose
The purpose of this paper is to establish the optimization model and solve the short‐term economic dispatch of cascaded hydro‐plants.
Design/methodology/approach
An improved particle swarm optimization (IPSO) approach is proposed to solve the short‐term economic dispatch of cascaded hydroelectric plants. The water transport delay time between connected reservoirs is taken into account and it is easy in dealing with the difficult hydraulic and power coupling constraints using the proposed method in practical cascaded hydroelectric plants operation. The feasibility of the proposed method is demonstrated for actual cascaded hydroelectric plant.
Findings
The simulation results show that this approach can prevent premature convergence to a high degree and keep a rapid convergence speed.
Research limitations/implications
The optimal values of parameters in the proposed method are the main limitations where the method will be applied to the economic operation of the hydro‐plant.
Practical implications
The paper presents useful advice for short‐term economic operations of the hydro‐plant. A new optimization method to solve the short‐term optimal generation scheduling is proposed. The optimal generation power and water discharge during the whole dispatching time for hydro‐plant operation can be obtained.
Originality/value
The IPSO method is realized by maintaining high diversity of the swarm during the optimization process and preventing premature convergence.
Details
Keywords
Xiaopan Zhang, Xide Fu and Xiaohui Yuan
The purpose of this paper is to propose a rolling horizon procedure (RHP) to deal with the large‐scale and strongly NP‐hard problem on cooperative lockage‐timetables and…
Abstract
Purpose
The purpose of this paper is to propose a rolling horizon procedure (RHP) to deal with the large‐scale and strongly NP‐hard problem on cooperative lockage‐timetables and service‐policies of the five locks in the Three Gorges Project.
Design/methodology/approach
RHP based approach is composed of a series of periodical short‐time sub‐optimizations instead of global optimization. Each of the sub‐optimizations is modeled by a mixed‐integer‐programming and solved by a branch and bound algorithm with terminal penalty.
Findings
The RHP method is found to be effective and efficient. The size of the rolling horizon is positively correlated to the total weighted area of ships.
Research limitations/implications
Precision of short‐time predictions is the main limitation.
Originality/value
This procedure promotes the navigation capacity of the Three Gorges Project and proposes a solution to the lockage‐scheduling problem of the Three Gorges Project.
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Keywords
Ruey-Jer "Bryan" Jean, Ziliang Deng, Daekwan Kim and Xiaohui Yuan
Endogeneity is a potential threat to the validity of international marketing (IM) research. The purpose of this paper is to draw the attention of IM researchers to issues of…
Abstract
Purpose
Endogeneity is a potential threat to the validity of international marketing (IM) research. The purpose of this paper is to draw the attention of IM researchers to issues of endogeneity, to provide a comprehensive overview of the sources of endogeneity, and to discuss the statistical solutions.
Design/methodology/approach
The authors conduct the research in two steps. In the first step, the authors review the nature and sources of endogeneity specifically in IM research. In the second step, the authors review 60 IM papers on endogeneity published in the period 1995-2014 and assess the current practice of addressing endogeneity in the IM literature.
Findings
Sample selection bias and simultaneity are prevalent sources of endogeneity in IM research. Internationalization-performance relationship and innovation-export nexus are the two most frequently adopted models subject to potential endogeneity. Simply lagging the main independent variable is statistically flawed in dealing with endogeneity despite its popularity in IM research.
Research limitations/implications
First, a careful choice and application of methods are critical when addressing endogeneity. Second, the authors suggest the employment of multiple study methods to address endogeneity robustly. Third, to prevent or solve endogeneity in structural equation modeling, researchers may either collect data on independent and dependent variables from different respondents or employ a two-stage least squares approach. Finally, it is helpful to design dedicated models to prevent proactively potential endogeneity a priori.
Originality/value
The contribution of this study is twofold. First, it is the first in the literature to discuss the endogeneity issue specifically in IM research. In particular, the study elaborates the origins and consequences of the three most frequently confronted types of endogeneity in IM research. Second, the authors assess the four major methods of addressing endogeneity in IM research with a systematic discussion of the literature from the last two decades. The authors offer suggestions on how to minimize endogeneity in model design and empirical implementation for future IM research.
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Keywords
Xiaohui Yu, Fei Wang and Lina Wang
City wall is an important symbol of ancient Chinese cities with unique geographical and cultural characteristics. Thus, the preservation of this historic landmark is considered…
Abstract
City wall is an important symbol of ancient Chinese cities with unique geographical and cultural characteristics. Thus, the preservation of this historic landmark is considered significantly important. However, numerous residential construction activities and changes in ecological environment have destructed a great portion of the city walls in recent years. This study looks into the preservation of the ancient city walls from the systematic perspective and in line with the actual characteristics of Longdong Region to provide guideline measures for the protection and restoration of such landmark. Cognition and preservation are adopted extensively to investigate the specific situation of and the factors that influence the ancient city walls in this region. Preservation strategies for the city walls, including the “Axis-Point” system, planning control, and authenticity readability, are presented. The ancient city walls in Longdong Region can be preserved by protecting the entire region, the city, and the main wall body. The systematic method and preservation strategies at the “macro perspective,” “medium perspective” and “micro perspective” levels can solve the preservation problems of the ancient city walls in Longdong Region effectively.
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Keywords
Dalei Zhang, Xinwei Zhang, Enze Wei, Xiaohui Dou and Zonghao He
This study aims to improve the corrosion resistance of TA2-welded joints by superhydrophobic surface modification using micro-arc oxidation technology and low surface energy…
Abstract
Purpose
This study aims to improve the corrosion resistance of TA2-welded joints by superhydrophobic surface modification using micro-arc oxidation technology and low surface energy substance modification.
Design/methodology/approach
The microstructure and chemical state of the superhydrophobic film layer were analyzed using scanning electron microscopy, energy dispersive X-ray spectroscopy, three-dimensional morphology, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared absorption spectroscopy. The influence of the superhydrophobic film layer on the corrosion resistance of TA2-welded joints was investigated using classical electrochemical testing methods.
Findings
The characterization results showed that the super hydrophobic TiO2 ceramic membrane was successfully constructed on the surface of the TA2-welded joint, and the construction of the super hydrophobic film greatly improved the corrosion resistance of the TA2-welded joint.
Originality/value
The superhydrophobic TiO2 ceramic membrane has excellent corrosion resistance. The micro nanostructure in the superhydrophobic film can intercept air to form an air layer to prevent the corrosion medium from contacting the surface, thus, improving the corrosion resistance of the sample.
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Keywords
Digital economic innovation is associated with risks. The lack of a platform's profitability weakens the operation's ability to sustain innovators and increases the possibility of…
Abstract
Purpose
Digital economic innovation is associated with risks. The lack of a platform's profitability weakens the operation's ability to sustain innovators and increases the possibility of the business' termination. Relevant data demonstrate a significant upward trend in the exit of Chinese innovators of the digital economy. The study aims to clarify the role of an effective government and effective market in the prevention and control of the withdrawal of innovators.
Design/methodology/approach
Based on balanced panel data of 31 provinces and cities from 2010 to 2018, this study uses the individual fixed effect model to study the impact of the marketization level, the market's scale and government interventions on the withdrawal of innovators. Simultaneously, based on the spatial econometric model, this study examines the spatial spillover effect of the withdrawal of innovators.
Findings
Results indicate that government interventions have an inhibiting effect on the withdrawal of innovators. Moreover, there was a positive “U”-shaped nonlinear relationship between the marketization level and the withdrawal of innovators, and an inverse “U”-shaped nonlinear relationship between the market size and the withdrawal of innovators.
Originality/value
The paper first studies the relationship between the exit of innovators and government intervention, marketization level and field scale; takes the lead in the research on the role of the government and effective market in the prevention and control of the exit of innovators from the perspective of the exit of innovators and puts forward policy suggestions to promote the sustainable and healthy development of fintech innovation in China from the market scale and other aspects.
Details
Keywords
Yingshuang Liu, Ran Liu, Dalei Zhang, Shaohua Xing, Xiaohui Dou, Xinwei Zhang and Zonghao He
The corrosion behaviour of titanium alloy surface when fluid with different flow rates flows through welded joints with different residual heights was explored.
Abstract
Purpose
The corrosion behaviour of titanium alloy surface when fluid with different flow rates flows through welded joints with different residual heights was explored.
Design/methodology/approach
The experiment uses a combination of array electrodes and simulation.
Findings
It is found that when the weld reinforcement exists, the corrosion tendency of both ends of the weld metal is greater than that of other parts of the welded joint due to the influence of high turbulence kinetic energy and shear stress. The presence of weld reinforcement heights makes the fluid behind it fluctuate greatly. The passivation films of both the base metal (BM) at the rear and the heat-affected zone (HAZ) are more prone to corrosion than those of the front BM and HAZ, and the passivation film is rougher.
Originality/value
The combination of test and simulation was used to explore the influence of electrochemical and hydrodynamic factors on the corrosion behaviour of titanium alloy-welded joints when welding residual height existed.
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This paper aims to explore the impact of family ownership, and family commitment on employees' organizational identification (EOI) with Chinese family firms, and to test the…
Abstract
Purpose
This paper aims to explore the impact of family ownership, and family commitment on employees' organizational identification (EOI) with Chinese family firms, and to test the mediating effect of corporate social responsibility (CSR) on this relationship.
Findings
The result reveals that family commitment positively influences employees’ organizational identification (EOI) with Chinese family firms. It is also shown that insiders’ responsibility (i.e. investors’ and employees’ responsibility) and public responsibility (i.e. community responsibility) positively influence EOI, and partially mediate the relationship between family commitment and EOI with Chinese family firms. In addition, the result indicates that family ownership positively influences insiders’ responsibility (i.e. investors’, and employees’ responsibility), outsiders’ responsibility (i.e. consumers’ responsibility), environmental responsibility and legal and ethical responsibility, and family commitment positively moderates the relationship between family ownership and insiders’ responsibility (i.e. investors’ and employees’ responsibility), outsiders’ responsibility (i.e. partners’ and consumers’ responsibility) and public responsibility (i.e. environmental responsibility) in Chinese family firms.
Originality/value
This study is the first to examine empirically the relationship between family involvement (i.e. family ownership, family commitment) and EOI from the viewpoint of CSR in Chinese family firms. The study contributes to the understanding of the relationship between family involvement and EOI, as well as the understanding of the influence of CSR on EOI with Chinese family firms.
Details
Keywords
This paper aims to comment upon the governance systems of state‐owned enterprises in Shanghai and to consider the adequacy or otherwise of those governance structures.
Abstract
Purpose
This paper aims to comment upon the governance systems of state‐owned enterprises in Shanghai and to consider the adequacy or otherwise of those governance structures.
Design/methodology/approach
The paper presents a study of existing governance arrangements and structures and considers areas for possible reform.
Findings
A sound corporate governance system is of great significance not only to the healthy development of enterprises but also for the enterprises to survive when they face the economic crisis. With the continuous spread of the world economic crisis, how to improve the corporate governance of state‐owned enterprises in Shanghai so that they can pass the financial crisis period safely has become one urgent and critical issue.
Originality/value
The study presents detail and reform areas for further reflection.
Details