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The purpose of this study is to propose a fractal model of thermal contact conductance (TCC) of two spherical joint surfaces, considering friction coefficient based on the three-dimensional fractal theory.

The effects of friction coefficient, fractal parameters, radius of curvature and contact type on TCC were analyzed using numerical simulation.

The results indicate that the TCC decreases with the increase of friction coefficient and fractal roughness and increases with the increase of fractal dimension and radius of curvature; the contact type of two spherical joint surfaces has an important influence on the TCC, and the TCC of external contact is smaller than that of internal contact under the same contact load.

A fractal model of TCC of two spherical joint surfaces considering friction coefficient is proposed in this paper. Achievements of this work provide some theoretical basis for the research of TCC of bearings and other curved surfaces.

This study aims to propose a new airport gate assignment method to effectively improve the comprehensive operation capacity and efficiency of hub airport. Gate assignment is one of the most important tasks for airport ground operations, which assigns appropriate airport gates with high efficiency reasonable arrangement.

In this paper, on the basis of analyzing the characteristics of airport gates and flights, an efficient multi-objective optimization model of airport gate assignment based on the objectives of the most balanced idle time, the shortest walking distances of passengers and the least number of flights at apron is constructed. Then an improved ant colony optimization (ICQACO) algorithm based on the ant colony collaborative strategy and pheromone update strategy is designed to solve the constructed model to fast realize the gate assignment and obtain a rational and effective gate assignment result for all flights in the different period.

In the designed ICQACO algorithm, the ant colony collaborative strategy is used to avoid the rapid convergence to the local optimal solution, and the pheromone update strategy is used to quickly increase the pheromone amount, eliminate the interference of the poor path and greatly accelerate the convergence speed.

The actual flight data from Guangzhou Baiyun airport of China is selected to verify the feasibility and effectiveness of the constructed multi-objective optimization model and the designed ICQACO algorithm. The experimental results show that the designed ICQACO algorithm can increase the pheromone amount, accelerate the convergence speed and avoid to fall into the local optimal solution. The constructed multi-objective optimization model can effectively improve the comprehensive operation capacity and efficiency. This study is a very meaningful work for airport gate assignment.

An efficient multi-objective optimization model for hub airport gate assignment problem is proposed in this paper. An improved ant colony optimization algorithm based on ant colony collaborative strategy and the pheromone update strategy is deeply studied to speed up the convergence and avoid to fall into the local optimal solution.

The gait planning and control of quadruped crawling robot affect the stability of the robot walking on a slope. The control includes the position control in the swing phase, the force control in the support phase and the switching control in the force/position switching. To improve the passing ability of quadruped crawling robot on a slope, this paper aims to propose a soft control strategy.

The strategy adopts the statically stable crawling gait as the main gait. As the robot moves forward, the position/force section switching control is adopted. When the foot does not touch the ground, the joint position control based on the variable speed PID is performed. When the foot touches the ground, the position-based impedance control is performed, and a fuzzy multi-model switching control based on friction compensation is proposed to achieve smooth switching of force and position.

The proposed method offers a solution for stable passage in slope environment. The quadruped crawling robot can realize smooth switching of force/position, precise positioning in the swing process and soft control of force in the supporting phase. This fact is verified by simulation and test.

The method presented in this paper takes advantage of minimal tracking errors and minimal jitters. Simulations and tests were performed to evaluate the performance.

Aiming at the problem that quadruped crawling robot is easy to collide and overturn when facing obstacles and bulges in the process of complex slope movement, this paper aims to propose an obstacle avoidance gait planning of quadruped crawling robot based on slope terrain recognition.

First, considering the problem of low uniformity of feature points in terrain recognition images under complex slopes, which leads to too long feature point extraction time, an improved ORB (Oriented FAST and Rotated BRIEF) feature point extraction method is proposed; second, when the robot avoids obstacles or climbs over bumps, aiming at the problem that the robustness of a single step cannot satisfy the above two motions at the same time, the crawling gait is planned according to the complex slope terrain, and a robot obstacle avoidance gait planning based on the artificial potential field method is proposed. Finally, the slope walking experiment is carried out in the Robot Operating System.

The proposed method provides a solution for the efficient walking of robot under slope. The experimental results show that the extraction time of the improved ORB extraction algorithm is 12.61% less than the original ORB extraction algorithm. The vibration amplitude of the robot’s centroid motion curve is significantly reduced, and the contact force is reduced by 7.76%. The time it takes for the foot contact force to stabilize has been shortened by 0.25 s. This fact is verified by simulation and test.

The method proposed in this paper uses the improved feature point recognition algorithm and obstacle avoidance gait planning to realize the efficient walking of quadruped crawling robot on the slope. The walking stability of quadruped crawling robot is tested by prototype.

Supply chain risk management can effectively reduce the loss of retailers. In this regard, retailers need to consider the competition risks of competitors in addition to the disruption risks. This paper designs a resilient retail supply chain network for perishable foods under the dynamic competition to maximize retailer's profits.

A two-stage mixed-integer non-linear model is presented for designing the supply chain network. In the first stage, an equilibrium model that considers the characteristics of perishable foods is developed. In the second stage, a mixed integer non-linear programming model is presented to deal with the strategic decisions. Finally, an efficient memetic algorithm is designed to deal with large-scale problems.

The optimal the selection of suppliers, distribution centers and the order allocation are found among the supply chain entities. Considering the perishability of agri-food products, the equilibrium retail price and selling quantity are determined. Through a numerical example, the optimal inventory period under different maximum shelf life and the impact of three resilient strategies on retailer's profit, selling price and selling quantity are analyzed.

As for future research, the research can be extended in a number of directions. First, this paper studies the retail supply chain network design problem under competition among retailers. It can be an interesting direction to consider retailers competing with suppliers. Second, the authors can try to linearize the non-linear model and solve the large-scale integer programming problem by exact algorithm. Finally, the freshness of perishable foods gradually declines linearly to zero as the maximum shelf life approaches, and it would be a meaningful attempt to consider the freshness of perishable foods declines exponentially.

This paper innovatively designs the resilient supply chain network for perishable foods under dynamic competition. The retailer's dynamic competition and resilient strategies are considered simultaneously when designing supply chain network for perishable foods. In addition, this paper gives insights into how to obtain the optimal inventory period and compare the retailer's resilient strategies.

This paper aims to introduce dataspace into digital libraries in order to address its emerging data management challenges which stem from cross-domain, heterogeneous, and uncertain nature of data resources, based on looking into the fundamental principles, significant features, and research directions of dataspace.

This research mainly employs three types of research methodologies: a literature study was conducted for revealing the fundamental principles, analyzing the significant features, and discussing the new research topics; knowledge engineering methodology is used to design the data model; software engineering methodology is applied to develop the reference framework and the digital library.

This paper for the first time proposes a motion to build a Dataspace Support Digital Library (DSDL), and provides its data model, data management policies and a reference framework. Further, its implementation is described and some implications learned from the case study are also discussed.

Introducing dataspace technologies into developing a digital library frees the developer to just focus on solving business challenges, rather than addressing non-business related, data management level tasks. In addition, the data model and the reference framework presented in this paper lay foundations for constructing Dataspace Support Digital Libraries.

This is the first paper to introduce dataspaces into the design of digital libraries and is also the first paper to propose a novel data model, data management and reference framework for Dataspace Support Digital Libraries.

Local brands in emerging markets suffer from fierce competition and chronic disadvantages. The purpose of this paper is to investigate if outbreaks of animosity against the West (AAW) might benefit local brands by raising consumers’ willingness to pay (WTP) and willingness to buy (WTB).

The study employed 2 methods: structural equation modeling (n=244 Chinese students); and experiment, multiple regression (n=676 Chinese students, different sample than those included in study 1).

AAW is different from ethnocentrism and the measurement has good validity and reliability. After an outbreak of animosity, AAW increases Chinese consumers’ WTB local products. The WTP is also enhanced by AAW in such a situation. Under “normal” circumstances, there is no effect of AAW on the WTP. This might be due to the cost of substituting western goods for local ones (e.g. inferior perceived quality and other-signaling value). An outbreak of animosity presents a risk to consumers and thus lowers their overall WTP.

The study introduces the construct “AAW,” which stretches the animosity construct to an inter-regional level. On such a level, it is possible to find consequences of animosity on local brand consumption, which have not been the focus of previous studies. Additionally, this research introduces the concept of WTP to animosity research. The measurement is built on a real economic exchange and better represents the cost aspects of substituting one brand for another.

This paper aims to propose a novel approach based on uniform scale-3 Haar wavelets for unsteady state space fractional advection-dispersion partial differential equation which arises in complex network, fluid dynamics in porous media, biology, chemistry and biochemistry, electrode – electrolyte polarization, finance, system control, etc.

Scale-3 Haar wavelets are used to approximate the space and time variables. Scale-3 Haar wavelets converts the problems into linear system. After that Gauss elimination is used to find the wavelet coefficients.

A novel algorithm based on Haar wavelet for two-dimensional fractional partial differential equations is established. Error estimation has been derived by use of property of compactly supported orthonormality. The correctness and effectiveness of the theoretical arguments by numerical tests are confirmed.

Scale-3 Haar wavelets are used first time for these types of problems. Second, error analysis in new work in this direction.