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Research on grey systems is becoming more sophisticated, and grey relational and prediction analyses are receiving close review worldwide. Particularly, the application of grey systems in marine economics is gaining importance. The purpose of this paper is to summarize and review literature on grey models, providing new directions in their application in the marine economy.

This paper organized seminal studies on grey systems published by Chinese core journal database – CNKI, Web of Science and Elsevier from 1982 to 2018. After searching the aforementioned database for the said duration, the authors used the CiteSpace visualization tools to analyze them.

The authors sorted the studies according to their countries/regions, institutions, keywords and categories using the CiteSpace tool; analyzed current research characteristics on grey models; and discussed their possible applications in marine businesses, economy, scientific research and education, marine environment and disasters. Finally, the authors pointed out the development trend of grey models.

Although researches are combining grey theory with fractals, neural networks, fuzzy theory and other methods, the applications, in terms of scope, have still not met the demand. With the increasingly in-depth research in marine economics and management, international marine economic research has entered a new period of development. Grey theory will certainly attract scholars’ attention, and its role in marine economy and management will gain considerable significance.

A self-adaptive piston is designed for the compressional gas cushion press nanoimprint lithography system. It avoids the lube pollution and high wear of traditional piston.

The self-adaptive piston device consists of symmetrical piston bodies, piston rings and other parts. The two piston bodies are linked by a ball-screw. The locking nut adjusts the distance between two piston bodies to avoid the piston rings from being stuck. The piston rings are placed between two piston bodies.

The simulation results based on COMSOL indicate that cylinder vibration caused by self-adaptive piston is 15.9 times smaller than the one caused by a traditional piston.

The self-adaptive piston is superior to the traditional piston in decreasing cylinder vibration.

The purpose of this paper is to comparatively investigate the microstructure and interfacial intermetallic compound (IMC) layer of Cu/SACPG/Ni and Cu/SAC0307/Ni solder joints after thermal aging.

The specimens were thermally aged at 150°C for 0, 24, 168 and 500 h. The microstructure and morphology of the interface IMC layer were observed by means of scanning electron microscope. The IMCs and the solder bump surface were analyzed by EDS. Moreover, the thickness of IMC layer was measured by using the image analysis software.

The morphology of IMC of Cu/SAC0307/Ni solder joint was consistent with that of the Cu/SACPG/Ni joint, which indicates that the addition of P and Ge had little effect on the IMC formation. The needle-like (Cu,Ni)6Sn5 was formed at the interface of solder/Ni solder joints. Meanwhile, the tiny particles inferred as Ag3Sn phase attached to the surface of (Cu,Ni)6Sn5. The growth rate of IMC layer of the Cu/SACPG/Ni joint was smaller than that of Cu/SAC0307/Ni joint with aging time increasing, which means the addition of trace P and Ge can slightly suppress the diffusion rate of the interfacial IMC.

There are no previous studies on the formation mechanism of the IMC layer of SAC0307 solder alloys with P and Ge addition.

This study aims to examine how the effect of pop-ups on an omnichannel brand’s subsequent online sales is moderated by the brand’s online price and premium promotions, paid search and popularity signaling.

Using a difference-in-differences approach, this study appraises variations in two similar Chinese apparel brands’ online sales before and after one of the brands’ implementations of its pop-ups and how the brand’s online promotions modify the pop-ups’ effect.

Unique, interactive pop-ups boost brands’ subsequent online sales. Online price promotions negatively moderate the effect; online premium promotions and paid search positively moderate it. Moreover, the product’s popularity diminishes the extent to which a pop-up stimulates online demand. These findings can be partially generalized to other categories, such as utilitarian products.

Only certain online strategies enhance the effect of pop-ups on brands’ online sales, so practitioners should strategically select appropriate promotion combinations when they operate pop-ups and allocate resources across channels. In addition, the moderating influence of online promotions on pop-ups depends on the type of product being promoted.

Pop-ups offer proven abilities to deliver sensory experiences to online shoppers, reinforce brand awareness and loyalty and boost online sales. This study extends prior research by examining how various online promotions moderate pop-ups’ effects.

This paper aims to propose an enhanced algorithm and used to decision-making that specifically focuses on the choice of a domain in the calculation of degree of greyness according to the principle of grey numbers operation. The domain means the emerging background of interval grey numbers, it is vital for the operational mechanism of such interval grey numbers. However, the criteria of selection of domain always remain same that is not only for the calculated grey numbers but also for the resultant grey numbers, which can be assumed as unrealistic up to a certain extent.

The existence of interval grey number operation based on kernel and the degree of greyness containing two calculation aspects, which are kernel and the degree of greyness. For the degree of greyness, it includes concepts of domain and calculation of the domain. The concepts of a domain are defined. The enhanced algorithm is also comprised of four deductive theorems and eight rules that are linked to the properties of the enhanced algorithm of the interval grey numbers based on the kernel and the degree of greyness.

Aiming to improve the algorithm of the degree of greyness for interval grey numbers, based on the variation of domain in the operation process, the degree of greyness of the operation result is defined in this paper, and the specific expressions for algebraic operations are given, which is relevant to the kernel, the degree of greyness and the domain. Then, these expressions are used to the algorithm of interval grey numbers based on the kernel and the degree of greyness, improving the accuracy of the operation results.

The enhanced algorithm in this paper can effectively reduce the loss of information in the operation process, so as to avoid the situation where the decision values are the same and scientific decisions cannot be made during the grey evaluation and decision-making process.

The purpose of this study was to comparatively investigate interfacial intermetallic compounds (IMCs) in the Sn3.0Ag0.5Cu3.0Bi0.05Cr/Cu (SACBC/Cu) and Sn3.0Ag0.5Cu/Cu (SAC/Cu) solder joints, and to determine any differences.

The samples were annealed after isothermal ageing at 150°C for 0, 168 and 500 hours, and their cross-sections were observed by scanning electron microscopy and energy dispersive spectroscopy.

The interfacial IMC morphology in two joints had significant differences. For the Cu/SAC/Cu joints, the granular and short rod-like Ag3Sn particles attached on the surface and boundary of interfacial Cu6Sn5 grains were detected, and they coarsened observably with ageing time at 150°C, and lastly embedded at the grain boundaries. However, for the Cu/SACBC/Cu joints, there were tiny filamentous Ag3Sn growing on the surface of interfacial Cu6Sn5 grains, and the Ag3Sn had a tendency to break into nanoparticles, which would be distributed evenly and cover the IMC layer, profiting from the Bi and Cr precipitates from solder matrix during ageing.

The paper implies that the addition of Bi and Cr could affect the IMCs of joints, thereby delaying interfacial reactions between Sn and Cu atoms and improving the service reliability. The SACBC solder is a potential alloy for electronic packaging production.

There are a large number of interdependent risk factors in complex project. Risk response strategy without considering risk correlation cannot achieve good risk response. Therefore, the purpose of this paper is to propose a risk response strategy selection model considering risk correlation based on the grey K-shell algorithm.

This paper mainly focuses on the measurement of two aspects of risk factors. One is the ability of the risk factors to influence other risk factors, another is the degree affected by other risk factors. Both of the above are measured by the grey K-shell algorithm improved in this paper, and the weights of these are used for the constructing of risk response strategy selection model.

The risk response strategy considering risk relevance is more effective than the risk response strategy without considering risk relevance. Also, results indicate that as the risk response budget increases the risk response effect also increases, and the increasing trend is weakens. The relative gap between the effect of response strategies considering risk relevance and the strategy without considering risk relevance increases first and, then, decreases with the increase of budget.

The results of this paper demonstrate that the risk response strategy considering risk relevance is more effective than not considering risk relevance. The approach presented in this paper can guide project managers’ risk decisions and may also help to find the best risk response budget.

The technical level of aircraft failure analysis plays a special role in ensuring the safety of civil aviation flight. Using appropriate methods for functional failures analysis can provide a reliable reference for aircraft safety. The purpose of this paper is to provide a new and comprehensive measure based on conventional functional hazard analysis (FHA) and grey system theory to analysis and evaluate the class that each failure belongs to.

This paper integrates multiple methods including the FHA, the fixed weight cluster, the Delphi method and the analytic hierarchy process (AHP). To begin with, use FHA method to sort out the corresponding failure states of a certain system from the perspective of function and determine the evaluation index. And then using group decision and AHP, determine the expert weight and index weight in the fixed weight cluster. The fixed weight cluster function is used to determine the grey class to which a certain functional failure belongs in the complex system.

In the past, the risk assessment of aircraft was mostly dominated by the subjective judgment of the experts, but it was not possible to give an objective observation score for each failure state. This paper addresses the problem efficiently as well as the feature of “little data, poor information.” The risk degree of each failure state can ultimately be replaced by a quantitative value.

This paper uses the idea of clustering in grey system theory to evaluate the risk of landing gear system. In the expert evaluation stage, different experts evaluated the impact degree of the aircraft's failure caused by its functions, so the final risk classification is subjective to some extent.

This study analyzed the different conditions of the landing gear, including the front wheel steering, front wheel damping, front wheel steering system, brake system fault information and so on. It can effectively divide the different failure states and their effects, which is helpful to improve the safety of aircraft landing gear system and provide some useful methods and ideas for studying the safety of aircraft systems.

Based on the FHA analysis process and the grey system theory, this paper determines various potential risks and their consequences of various functions according to the hierarchy, so as to carry out further detailed analysis on the risks that may occur under various functional conditions and take certain measures to prevent them. It is helpful to improve the risk management and control ability of aircraft in the actual flight process and to guarantee the safety of people's lives and property.

This paper is a pioneer in integrating the FHA method and the grey system theory, which exactly can be used to address the problem with the character of “little data, poor information.” The model established in this paper for the defects of FHA can effectively improve the accuracy of FHA, which is of great significance for the study of safety. In this paper, a case about landing gear system is given to illustrate the effectiveness of the model.

This paper aims to present a novel approach for computing particle temperatures in simulations coupling computational fluid dynamics (CFD) and discrete element method (DEM) to predict flow and heat transfer in fluidized beds of thermally thick spherical particles.

An improved lumped formulation based on Hermite-type approximations for integrals to relate surface temperature to average temperature and surface heat flux is used to overcome the limitations of classical lumped models. The model is validated through comparisons with analytical solutions for a convectively cooled sphere and experimental data for a fixed particle bed. The coupled CFD-DEM model is then applied to simulate a Geldart D bubbling fluidized bed, comparing the results to those obtained using the classical lumped model.

The validation cases demonstrate that ignoring internal thermal resistance can significantly impact the temperature in cases where the Biot number is greater than 0.1. The results for the fixed bed case clearly demonstrate that the proposed method yields significantly improved outcomes compared to the classical model. The fluidized bed results show that surface temperature can deviate considerably from the average temperature, underscoring the importance of accurately accounting for surface temperature in convective heat transfer predictions and surface processes.

The proposed approach offers a physically more consistent simulation without imposing a significant increase in computational cost. The improved lumped formulation can be easily and inexpensively integrated into a typical DEM solver workflow to predict heat transfer for spherical particles, with important implications for various industrial applications.

The purpose of this paper is to examine how subnational institutions within a country explain the performance consequences of open innovation (OI) in emerging market enterprises (EMEs).

The paper conducts a regression analysis by using a novel panel data set comprising of 438 innovative Chinese firms over the period of 2008-2011.

The authors show that although on average openness to external actors improves innovation performance this effect is pronounced for EMEs that operate in subnational regions with a higher level of intellectual property rights (IPR) enforcement and of factor market development. The findings point to the context-dependent nature of OI strategy and the complementary effect of institutional parameters in emerging markets and help to reconcile the contrasting findings regarding the effect of OI in the prior literature.

This paper extends the literature on OI by suggesting that the analysis of the performance consequences of OI strategy should go beyond the nexus between OI and firm performance, and instead, focus on subnational-specific institutions, such as region-specific IPR enforcement, factor market development and intermediation market development, that may facilitate or constrain the effect of OI model.