Search

Robustness of higher‐order network (HON) with dependency is different from first‐order network (FON), as the attack orders and the number of iterations are totally different. To measure the robustness of HON with dependency, this study proposed new attack strategies on node and edge failure through measuring the size of the giant component and global efficiency. And two real‐world systems of hazardous materials transportation accident causation system and Chinese high‐speed railway system with different network size were empirically studied. Results show that HON is more fragile to robustness attacks than FON. The number of attack iterations is uncertain in HON, which depends on the attack strategies and the network structure. Meanwhile, nodes and edges with high dependency have greater impacts on network robustness, providing valuable insights into capturing critical information. This study may be helpful to design the robust system, improve the system's reliability and serve as a valuable reference for future exploration of HONs robustness. [ABSTRACT FROM AUTHOR]

The connectivity of the urban public transport network and the convenience of transfers between modes of transit are important factors that affect whether passengers choose public transport. Identifying the key nodes that affect network connectivity, direct access, transfers, and clarifying the main factors that restrict the network efficiency play important roles in improving the efficiency of the public transport network and establishing a "green city". On this premise, this paper constructs two single-layer networks and a composite network that can reflect the transfer relationship between 'bus–bus', 'metro–metro', and 'metro–bus' based on the method of Space-P. The composite network realizes the integration study of homogeneous and heterogeneous stops, lines, and transfer relationships in the public transport network. At the same time, five kinds of centrality indexes are applied to the transport transfer network, and the significance of these indexes in the network is explained. Through the comprehensive analysis of these five types of indexes, the key nodes affecting the network connectivity, direct access and transfer efficiency, can be identified more accurately. Taking the public transport network of Xi'an as an example, the structural characteristics of the networks, including scale-free and small-world characteristics, were empirically analyzed. The main stops that play important roles in networks were identified based on the integrated centrality, degrees, and weight degrees. The research results showed the following: (1) Xi'an's metro network, bus network, and metro–bus composite network all have scale-free and small-world characteristics. (2) The influence of the key stops of the metro network is concentrated, while the influence of the key stops of the bus network is scattered. (3) The public transport network in the first ring road area of Xi'an has the highest degree of direct access, and the core areas of the south, west, and north of Xi'an also have high direct access. However, the direct access in the area east of Xi'an is slightly lower. (4) Xi'an's bus transport network covers a large area, showing the characteristics of a dual-core "central + southern" network. (5) The metro–bus composite network demonstrates a closer connection between stops and a more balanced network. (6) Finally, the degree of direct access to stops in the bus transport network and metro transport network shows the characteristics of "the single core is dominant, and the circle diffusion weakens step by step". [ABSTRACT FROM AUTHOR]

For the dynamic takeout delivery vehicle routing problem, which faces fluctuating order demand and time-varying speeds, this study presents a novel approach. We analyze the time distribution of takeout orders and apply a Receding Horizon Control (RHC) strategy to convert the dynamic challenge into a static one. The driving speed of delivery vehicles on different roads at different times is determined based on the subdivision criteria of the urban road network and a traffic congestion measurement method. We propose a dynamic takeout delivery vehicle routing optimization model and a time-varying subdivision road network is established to minimize the total delivery cost. We validated the model through simulation examples. The optimization results show that the total distribution cost is reduced after considering the time-varying subdivision road network, with the penalty cost decreasing by 39%. It is evident that considering the subdivision of the road network can enhance order delivery efficiency and optimize the overall dining experience. The sensitivity analysis of various parameters reveals that the delivery platform must appropriately determine the time domain and allocate the number of delivery personnel based on order scale to avoid escalating delivery costs. These findings provide theoretical guidance for vehicle routing planning in the context of delivery platforms. [ABSTRACT FROM AUTHOR]

This paper focuses on the application of higher-order and multilayer networks in identifying critical causes and relationships contributing to hazardous materials transportation accidents. There were 792 accidents of hazardous materials transportation that occurred on the road from 2017 to 2021 which have been investigated. By considering time sequence and dependency of causes, the hazardous materials transportation accidents causation network (HMTACN) was described using the higher-order model. To investigate the structure of HMTACN such as the importance of causes and links, HMTACN was divided into three layers using the weighted k-core decomposition: the core layer, the bridge layer and the peripheral layer. Then causes and links were analyzed in detail. It was found that the core layer was tightly connected and supported most of the causal flows of HMTACN. The results showed that causes should be given hierarchical attention. This study provides an innovative method to analyze complicated accidents, which can be used in identifying major causes and links. And this paper brings new ideas about safety network study and extends the applications of complex network theory. [ABSTRACT FROM AUTHOR]

Based on the complex network theory, we explore an express delivery system in China, which consists of two delivery networks, namely, the air delivery network (ADN) and the ground delivery network (GDN). Systematic structural analysis indicates that both delivery networks exhibit small-world phenomenon, disassortative mixing behavior, and rich-club phenomenon. However, there are significant differences between ADN and GDN in terms of degree distribution property and community structure. On the basis of the Barabási-Albert model, we have proposed a network model incorporating the structural features of the two delivery networks to reveal their evolutionary mechanisms. Lastly, the parcel strength and the distance strength are analyzed, which, respectively, reflect the number of parcels and the long-haul delivery distance handled by a node city. The strengths are highly heterogeneous in both delivery networks and have intense correlations with topological structures. These works are beneficial for express enterprises to construct or extend their express delivery networks, and provide some useful insights on improving parcel delivery service. © 2014 Wiley Periodicals, Inc. Complexity 21: 166-179, 2015 [ABSTRACT FROM AUTHOR]

We study the emergence of cooperation in an environment where players in prisoner's dilemma game (PDG) not only update their strategies but also change their interaction relations. Different from previous studies in which players update their strategies according to the imitation rule, in this article, the strategies are updated with limited foresight. We find that two absorbing states-full cooperation and full defection-can be reached, assuming that players can delete interaction relations unilaterally, but new relations can only be created with the mutual consent of both partners. Simulation experiments show that high levels of cooperation in large populations can be achieved when the temptation to defect in PDG is low. Moreover, we explore the factors which influence the level of cooperation. These results provide new insights into the cooperation in social dilemma and into corresponding control strategies. © 2012Wiley Periodicals, Inc. Complexity, 2012 [ABSTRACT FROM AUTHOR]

Objective: To investigate the clinical application of modified percutaneous rotating dilative tracheostomy with fiberoptic bronchoscope (MPRDT-FOB) in critical patients of intensive care unit (ICU) by comparing it with percutaneous dilative tracheostomy (PDT), modified percutaneous dilative tracheostomy (MPDT), and percutaneous dilative tracheostomy with fiberoptic bronchoscope (PDT-FOB)., Methods: A prospective control study was conducted. 240 critical patients underwent tracheotomy admitted to ICU of Mudanjiang Medical University Hongqi Hospital from February 2011 to November 2016 were enrolled, and they were randomly divided into four groups with 60 patients in each group. The patients in PDT group received traditional Portex method for tracheotomy. The patients in MPDT group received PDT method first, in the process of puncture and expansion, the trachea catheter was always retained in situ, and then retreated to the puncture site about 16-18 cm from incisor after withdrawal of the dilator. The patients in PDT-FOB group received PDT with fiberoptic bronchoscope. The patients in MPRDT-FOB group received PDT-FOB combined with MPDT, in bronchoscope expansion incision, and was replaced with rotary expander to the anterior wall of the trachea. The duration of operation, the size of incision, blood loss during operation, and the rate of disposable success, as well as the incidence of perioperative and long-term complications among four kinds of tracheostomy were compared., Results: Compared with PDT and PDT-FOB, the duration of operation in MPDT and MPRDT-FOB was significantly shortened (minutes: 6.57±3.59, 7.09±2.55 vs. 12.20±2.01, 10.13±2.37), the size of incision was significantly diminished (cm: 1.20±1.00, 1.20±0.90 vs. 1.59±1.18, 1.32±1.24), and the amount of blood loss during operation was significantly decreased (mL: 6.81±2.19, 6.60±1.99 vs. 10.28±3.68, 8.11±2.96, all P < 0.05). There were no significant differences in above parameters between MPDT and MPRDT-FOB, but those in MPRDT-FOB were better than MPDT, and the rate of disposable success in MPRDT-FOB was significantly higher than that of MPDT [100.00% (60/60) vs. 91.67% (55/60), P < 0.05]. The perioperative complications of four methods, such as postoperative bleeding, arrhythmia and bronchospasm, were recorded, but the incidences in MPRDT-FOB were lower than those of PDT, MPDT, and PDT-FOB. Patients in PDT and MPDT had more posterior wall injury or perforation, aspiration and intubation difficulties, while PDT-FOB and MPRDT-FOB had no above complications. The most common long-term complication of PDT was tracheal fistula, and the incidence was significantly higher than that of MPDT (25.00% vs. 13.33%, P < 0.05). However, there was no tracheoesophageal fistula report in PDT-FOB and MPRDT-FOB. Incision swallowing dysfunction, excessive phlegm, incision infection, tube collapse, airway stenosis, delayed healing, granulation or scar, and other complications of the four methods group were rare, and the differences was not statistically significant (all P > 0.05)., Conclusions: It was proved that MPRDT-FOB to be a time-saving, easy-to-operate way with few complication. Moreover, it was able to deal with the problems of the tracheal wall injury or perforation, tracheoesophageal fistula, and hypoxia. Hence, it was better than PDT, MPDT, and PDT-FOB.

Complement anaphylatoxins have been investigated extensively; however, the role of complement anaphylatoxin C4a in hyperoxic lung injury has yet to be investigated. To the best of our knowledge, the present study is the first to demonstrate the role of C4a in hyperoxic lung injury in vitro and in vivo. BALB/c mice were ventilated with 100% oxygen with or without C4a treatment for 36 h. The body weight and the relative lung weight of the mice were determined, along with any morphological changes in the lung. The expression levels of interleukin (IL)-1, IL-6 and tumor necrosis factor-α (TNF-α) were quantified in the lung tissue and bronchoalveolar lavage fluid (BALF) samples by enzyme-linked immunosorbent assay (ELISA) and western blot analysis. The total cell count and the number of macrophages, neutrophils and lymphocytes in the BALF were determined using cytocentrifuge slides and a hemocytometer. Histamine release from total cells in the BALF was also analyzed. The relative mRNA expression levels of CD68, F4/80, CD64, CD19 and CD3 in the murine lung tissue were assessed by reverse transcription-quantitative polymerase chain reaction. The results revealed that hyperoxia induced lung injury and morphological changes, and increased the expression levels of IL-1, IL-6 and TNF-α, histamine release, the number of inflammatory cells, and the expression levels of CD68, F4/80, CD64, CD19 and CD3. The hyperoxia-induced morphological changes and inflammatory reaction were significantly attenuated in mice treated with C4a. Treatment with C4a also attenuated the increase in the total cell count, decreased the number of macrophages in the BALF, and suppressed the elevated mRNA expression levels of CD68 and F4/80 in the lung tissue samples. Conversely, treatment with C4a did not affect the number of neutrophils or lymphocytes in the BALF or the mRNA expression of CD64, CD19 and CD3 in lung tissue. In conclusion, C4a attenuated hyperoxic lung injury via a macrophage-dependent but not a neutrophil/lymphocyte-dependent pathway.