R-CA: A Routing-based Dynamic Channel Assignment Algorithm for Wireless Mesh Networks

Even though channel assignment has been studied for years, the performance of most IEEE 802.11-based multi-hop wireless networks such as wireless sensor network (WSN), wireless mesh network (WMN), mobile ad hoc network (MANET) is limited by channel interference. Properly assigning orthogonal channels to wireless links can improve the throughput of multi-hop networks. To solve the dynamic channel assignment problem, a routing-based channel assignment algorithm called R-CA is proposed. R-CA can allocate channels for wireless nodes when needed and free channels after data transmission. Thus more channel resource can be explored by wireless nodes. Simulation results show that R-CA can effectively enhance the network throughput and packet delivery rate.Comment: International Workshop on Mobile Cyber-Physical Systems (MobiCPS 2010), in conjunction with UIC2010, IEEE, Xi'an, China, 26 - 29 October, 201

Spatial and Temporal Differentiation of the Tourism Water Footprint in Mainland China and Its Influencing Factors

While tourism generates economic benefits at destinations, it also creates certain environmental pressures. In the global context of water scarcity, the spatial and temporal differentiation characteristics of water consumption at tourism destinations have become a focus of attention. Based on panel data, the present study calculates the change trends in China’s tourism water footprint (TWF) in the 2013–2018 period using input-output analysis, analyses the regional differences in TWF changes using kernel density estimation and the Theil index, and investigates the driving factors of the spatial and temporal differentiation of the TWF using the logarithmic mean Divisia index model. The results indicate that (1) the tourism water consumption in China increased year-by-year but that the tourism water use efficiency improved; (2) the proportion of the TWF for accommodation and food in the total TWF gradually increased, while the proportion of the TWF for transportation continuously decreased; (3) the TWF of each region increased continuously, with the absolute difference between regions gradually increasing and the difference in the TWF intensity gradually decreasing; and (4) decomposition analysis showed that the TWF in China was positively driven by per capita expenditure and the number of tourists, with the role of TWF intensity shifting from inhibition to promotion, and that each driving force changed with time. Based on the spatial and temporal differences in the TWF, the provinces in China are divided into five categories, and targeted countermeasures and suggestions are proposed

Spatiotemporal Evolution of Tourism Eco-Efficiency in Major Tourist Cities in China

Tourism development consumes ecological resources to varying extents while bringing economic benefits; tourism eco-efficiency (TEE) assessment has thus become an area of major focus in destination sustainability research. This paper intends to examine the spatiotemporal characteristics and driving factors of eco-efficiency changes in 36 tourist cities on the Chinese mainland from 2010 to 2019, using a super-slacks-based measure (SBM) model, the data envelopment analysis (DEA)–Malmquist index, spatial correlation, and regression analysis. In contrast to the previous work, this work explores TEE among major tourist cities in China by considering the undesirable outputs of carbon emissions and sewage. The results show that (1) the TEE of most cities during the study period was low but increasing; there were significant spatial differences among different cities, and the eco-efficiency of the same city fluctuated over time. (2) The TEE was globally uncorrelated, but low-eco-efficiency areas were adjacent to each other and formed agglomerates, enhancing the negative spillover effect. (3) Despite fluctuations, the Malmquist indices exhibited positive trends, which resulted from the technical progress index rather than the technical efficiency index. (4) Socioeconomic development significantly promoted TEE. This research reveals the evolutionary law of TEE on the urban scale and explores the impact of social and economic development on TEE, which can provide a reference for policymaking and enrich research on destination sustainability

Spatiotemporal Evolution of Tourism Eco-Efficiency in Major Tourist Cities in China

Tourism development consumes ecological resources to varying extents while bringing economic benefits; tourism eco-efficiency (TEE) assessment has thus become an area of major focus in destination sustainability research. This paper intends to examine the spatiotemporal characteristics and driving factors of eco-efficiency changes in 36 tourist cities on the Chinese mainland from 2010 to 2019, using a super-slacks-based measure (SBM) model, the data envelopment analysis (DEA)–Malmquist index, spatial correlation, and regression analysis. In contrast to the previous work, this work explores TEE among major tourist cities in China by considering the undesirable outputs of carbon emissions and sewage. The results show that (1) the TEE of most cities during the study period was low but increasing; there were significant spatial differences among different cities, and the eco-efficiency of the same city fluctuated over time. (2) The TEE was globally uncorrelated, but low-eco-efficiency areas were adjacent to each other and formed agglomerates, enhancing the negative spillover effect. (3) Despite fluctuations, the Malmquist indices exhibited positive trends, which resulted from the technical progress index rather than the technical efficiency index. (4) Socioeconomic development significantly promoted TEE. This research reveals the evolutionary law of TEE on the urban scale and explores the impact of social and economic development on TEE, which can provide a reference for policymaking and enrich research on destination sustainability

A Novel Method for the Localization and Management of Traumatic Cyclodialysis Cleft

Purpose. To propose a novel surgical method for the localization and management of traumatic cyclodialysis clefts. Methods. Five patients with traumatic cyclodialysis clefts who underwent the innovative surgery were retrospectively reviewed. The new method was introduced to repair a cyclodialysis cleft with two running sutures from the middle to each end of the cleft under the guidance of a probe. Preoperative and postoperative visual acuity (VA), intraocular pressure (IOP), slit lamp and gonioscopic results, ultrasound biomicroscopy (UBM), and optical coherence tomography (OCT) findings were recorded. Results. Cyclodialysis clefts were completely closed postoperatively in four patients (four eyes); this was confirmed by progressively improved VA, restoration into the normal range of the IOP, disappearance of suprachoroidal fluid, and reduced macular edema. Only one patient with multiple clefts had an incomplete reattachment. Conclusions. This clinical study offers a novel and efficient method to localize and repair the cyclodialysis clefts

Iris reconstruction combined with iris-claw intraocular lens implantation for the management of iris-lens injured patients

Aim: To study the efficiency and safety of iris reconstruction combined with iris-claw intraocular lens (IOL) implantation in the patients with iris-lens injuries. Settings and Design: Retrospective, noncomparable consecutive case series study. Materials and Methods: Eleven patients (11 eyes) following iris-lens injuries underwent iris reconstructions combined with iris-claw IOL implantations. Clinical data, such as cause and time of injury, visual acuity (VA), iris and lens injuries, surgical intervention, follow-up period, corneal endothelial cell count, and optical coherence tomography, were collected. Results: Uncorrected VA (UCVA) in all injured eyes before combined surgery was equal to or <20/1000. Within a 1.1–4.2-year follow-up period, a significant increase, equal to or better than 20/66, in UCVA was observed in six (55%) cases, and in best-corrected VA (BCVA) was observed in nine (82%) cases. Postoperative BCVA was 20/40 or better in seven cases (64%). After combined surgery, the iris returned to its natural round shape or smaller pupil, and the iris-claw IOLs in the 11 eyes were well-positioned on the anterior surface of reconstructed iris. No complications occurred in those patients. Conclusions: Iris reconstruction combined with iris-claw IOL implantation is a safe and efficient procedure for an eye with iris-lens injury in the absence of capsular support

Coupling Plant Polyphenol Coordination Assembly with Co(OH)₂ to Enhance Electrocatalytic Performance towards Oxygen Evolution Reaction

The oxygen evolution reaction (OER) is kinetically sluggish due to the limitation of the four-electron transfer pathway, so it is imperative to explore advanced catalysts with a superior structure and catalytic output under facile synthetic conditions. In the present work, an easily accessible strategy was proposed to implement the plant-polyphenol-involved coordination assembly on Co(OH)2 nanosheets. A TA-Fe (TA = tannic acid) coordination assembly growing on Co(OH)2 resulted in the heterostructure of Co(OH)2@TA-Fe as an electrocatalyst for OER. It could significantly decrease the overpotential to 297 mV at a current density of 10 mA cm−2. The heterostructure Co(OH)2@TA-Fe also possessed favorable reaction kinetics with a low Tafel slope of 64.8 mV dec−1 and facilitated a charge-transfer ability. The enhanced electrocatalytic performance was further unraveled to be related to the confined growth of the coordination assembly on Co(OH)2 to expose more active sites, the modulated surface properties and their synergistic effect. This study demonstrated a simple and feasible strategy to utilize inexpensive biomass-derived substances as novel modifiers to enhance the performance of energy-conversion electrocatalysis

Concave ZnFe₂O₄ Hollow Octahedral Nanocages Derived from Fe-Doped MOF‑5 for High-Performance Acetone Sensing at Low-Energy Consumption

Herein, through a morphology-inherited annealing treatment of a hollow Fe-doped MOF-5 octahedron as the self-sacrificing template, we report the synthesis of concave ZnFe₂O₄ hollow octahedral nanocages as sensing materials, which exhibited high performance, including unprecedented excellent sensitivity, good selectivity, and cyclic stability at ultralow working temperature (120 °C)