Hierarchical Fusion Process of Destination Image Formation: Targeting on Urban Tourism Destination

Image has been widely accepted as a combination of perceived elements that are commonly discrete and static ones. ‘Discrete’ means that the elements are treated as separate ones with each other, with no interactions among them. ‘Static’ means that the elements would not be changed into other forms in the process of destination image formation. This study, thinking outside the box, tries to explore destination image formation through perceived elements and take their interactions and corresponding changes into account. Machine learning, as the core of artificial intelligence, is applied for data analysis in this study. Urban tourism destinations are targeted because of their variety and abundance of perceived elements. Data are collected from both interview and questionnaire surveys of tourists. Through several phases of analysis, this study finally finds that perceived elements do interact with each other and change into new forms level by level in tourism destination image formation. Specifically, there are four levels from bottom to top in the whole process of destination image formation, i.e., the individual-landscape layer, compound-atmosphere layer, dual-factor layer, and overall-image layer. In the bottom stage, elements are commonly numerous, separate, and concrete. With the interactive effects of the elements, they integrate with each other and generate some new forms in higher levels, which would be more general and abstract. Based on the findings, the dynamic fusion process and pyramid hierarchy of destination image formation are disclosed. This study explores destination image formation from a new perspective, considering perceived elements within a dynamic, synthetic system, and therefore provides practical insights into destination image construction in a more comprehensive and targeted way.

Optimization and Decision of Supply Chain Considering Negative Spillover Effect and Service Competition

Excellent service plays a vital role in the sustainability of enterprise and supply chains development in today’s increasingly fierce market competition. However, due to the inevitable spillover effect in the competitive network, enterprises’ initiative to improve the service level is reduced. From the perspective of negative spillover effect, optimization and decision-making in the competitive network of retailer-dominated supply chain are examined in this study. Considering four competitive situations in practical operation management, the corresponding double-layer compound nested Stackelberg game models are constructed, and the optimal equilibrium solutions are derived. Employing comprehensive comparison and analysis of the results, it is found that when the negative spillover effect of service increases, the optimal profit and service level of the leading supply chain or its retailers decrease, and the optimal retail price and overall optimal profit also gradually decline. For the leading supply chain, the centralized decision-making can achieve higher profits, and also more willing to improve the level of service. However, for the following supply chain, when the negative spillover effect of service is weak, the optimal service level under decentralized decision is higher, while when the spillover effect of service is strong, the optimal service level under integrated decision is higher. In addition, the supply chain-to-chain competition can bring negative incentives to the retailer that provides services, while for the rival that does not provide services, it can generate a certain free-riding effect that benefits them, and the effect is enhanced with the increase of competition.

Design and Analysis of Reflectarray Compound Unit Cell for 5G Communication

In this paper, a single-layer compound unit element is proposed for reflectarray antenna design operating in Ka-band (26.5-29.5GHz) at the center frequency of 28GHz. A systematic study on the performance of a compound unit element is examined first. The structure of the proposed unit element is a unique combination of two different shape simple patches i.e. cross dipole and square patches. The desired phase range is achieved due to the multi-resonance of both patch elements with a single layer without any air-gap. The compound unit element is simulated by computer models of CST Microwave studio based on the Floquet approach (infinite periodic approach) and it has achieved 348.589o reflection phase range. Furthermore, the analysis of the reflection phase range, S-curve gradient, reflection magnitude, fabrication tolerance, and surface current density is also simulated and demonstrated. Based on the remarkable performance, the proposed element can be considered as the best element of single-beam or multi-beam reflectarray antenna design for 5G applications.

Design of a Mechanical Sealing Device for Robotic Water Distribution Pipe Rehabilitation

Water distribution pipe maintenance is a global concern. In this study, we propose a Rehabilitation In-Pipe Robot (R-IPR) to perform pipe rehabilitation operations and contain induced contamination. The robot features three modules: a pipe cleaning module, a mechanical sealing module, and an in-pipe manipulator module. This study emphasizes the comprehensive design of the mechanical sealing module. We introduce a multi-layer compound structure of the seal to deal with two characteristics of tuberculated pipe surfaces: 1. macroscopical surface roughness, 2. overhang in foundation profile. The prototype excels in sealing foundation overhang and requires 45% lower compression load than a baseline seal to function. The prototype seal is integrated into the R-IPR. Finally, experiments of the overall system demonstrate the successful performance of the first contamination-less in-pipe rehabilitation.

Electronic structures and topological properties in nickelates Lnn + 1NinO2n + 2

After the significant discovery of the hole-doped nickelate compound Nd0.8Sr0.2NiO2, an analysis of the electronic structure, orbital components, Fermi surfaces and band topology could be helpful to understand the mechanism of its superconductivity. Based on the first-principles calculations, we find that Ni $3d_{x^2-y^2}$ states contribute the largest Fermi surface. $Ln~5d_{3z^2-r^2}$ states form an electron pocket at Γ, while 5dxy states form a relatively bigger electron pocket at A. These Fermi surfaces and symmetry characteristics can be reproduced by our two-band model, which consists of two elementary band representations: B1g@1a ⊕ A1g@1b. We find that there is a band inversion near A, giving rise to a pair of Dirac points along M–A below the Fermi level upon including spin-orbit coupling. Furthermore, we have performed the DFT+Gutzwiller calculations to treat the strong correlation effect of Ni 3d orbitals. In particular, the bandwidth of $3d_{x^2-y^2}$ has been renormalized largely. After the renormalization of the correlated bands, the Ni 3dxy states and the Dirac points become very close to the Fermi level. Thus, a hole pocket at A could be introduced by hole doping, which may be related to the observed sign change of Hall coefficient. By introducing an additional Ni 3dxy orbital, the hole-pocket band and the band inversion can be captured in our modified model. Besides, the nontrivial band topology in the ferromagnetic two-layer compound La3Ni2O6 is discussed and the band inversion is associated with Ni $3d_{x^2-y^2}$ and La 5dxy orbitals.