49 research outputs found

    Pricing Strategies in Dual-online Channels Based on Consumers’ Shopping Choice

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    AbstractBesides an official website mall (OWM), retail stores on the third party e-commerce platform(3PEP) is an another important online channel that manufacturers adopt to sell online. How to properly price products in these two channels simultaneously is a tough problem to firms and gains much attention by researchers. In this paper, we analyze their channel choice, and give demand functions of the two channels based on the consumers’ segmentation and preference. Then we design a sale model including two online channels: OWM and a retail store on 3PEP. According the Stackelberg game theory, we calculate and discuss the optimal pricing strategies of the manufacturer and retailer in three feasible regions. The result shows that manufacturers emphasizing channel sales prefer to choose pricing strategies that helps two online channels share the online market. But some manufacturers think adjusting the OWM's price and the wholesale price to control the retailer's pricing strategies is reasonable and necessary, even if nobody will prefer the OWM

    Adjacent Graph Based Vulnerability Assessment for Electrical Networks Considering Fault Adjacent Relationships Among Branches

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    Security issues related to vulnerability assessment in electrical networks are necessary for operators to identify the critical branches. At present, using complex network theory to assess the structural vulnerability of the electrical network is a popular method. However, the complex network theory cannot be comprehensively applicable to the operational vulnerability assessment of the electrical network because the network operation is closely dependent on the physical rules not only on the topological structure. To overcome the problem, an adjacent graph (AG) considering the topological, physical, and operational features of the electrical network is constructed to replace the original network. Through the AG, a branch importance index that considers both the importance of a branch and the fault adjacent relationships among branches is constructed to evaluate the electrical network vulnerability. The IEEE 118-bus system and the French grid are employed to validate the effectiveness of the proposed method.National Natural Science Foundation of China under Grant U1734202National Key Research and Development Plan of China under Grant 2017YFB1200802-12National Natural Science Foundation of China under Grant 51877181National Natural Science Foundation of China under Grant 61703345Chinese Academy of Sciences, under Grant 2018-2019-0

    Global research status and frontiers on microvascular invasion of hepatocellular carcinoma: A bibliometric and visualized analysis

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    IntroductionOver the past decade, several studies on the microvascular invasion (MVI) of hepatocellular carcinoma (HCC) have been published. However, they have not quantitatively analyzed the remarkable impact of MVI. Therefore, a more comprehensive understanding of the field is now needed. This study aims to analyze the evolution of HCC-MVI research and to systematically evaluate the scientific outputs using bibliometric citation analysis.MethodsA systematic search was conducted on the Web of Science Core Collection on 2 May 2022 to retrieve studies on HCC-MVI published between 2013 and 2022. Then, a bibliometric analysis of the publications was performed using CiteSpace, VOSviewer, and other visualization tools.ResultsA total of 1,208 articles on HCC MVI were identified. Of these, China (n = 518) was the most prolific country, and Fudan University (n = 90) was the most notable institution. Furthermore, we observed that Lau Wan Yee participated in most studies (n = 26), and Frontiers in Oncology (IF2020:6.24) published the highest number of documents (n = 49) on this subject, with 138 publications. The paper “Bray F, 2018, CA-CANCER J CLIN, V68, P394” has the highest number of co-cited references, with 119 citations. In addition, the top three keywords were “survival”, “recurrence”, and “microvascular invasion”. Moreover, the research hot spots and frontiers of HCC-MVI for the last 3 years included imaging characteristics and transarterial chemoembolization (TACE) therapy studies.ConclusionsThis study comprehensively summarized the most significant HCC-MVI documents from past literature and highlighted key contributions made to the advancement of this subject and the advancement of this field over the past decade. The trend of MVI research will gradually shift from risk factors and prognosis studies to imaging characteristics and TACE therapy studies

    Collection-disassembly-delivery problem of disassembly centers in a reverse logistics network

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    Disassembly centers are essential in a reverse logistics network for breaking end-of-life products and recycling valuable materials. This paper studies a collection-disassembly-delivery problem for a disassembly center, which collects products from collection centers, disassembles products into materials and delivers materials to remanufacturing plants. A set of homogenous vehicles are available for collecting products and delivering materials. The disassembly center makes the best decision on disassembly, inventory, and vehicle routing for collecting products and delivering materials. We propose a mixed-integer linear programming model to formulate the problem, and then improve the two-phase iterative heuristic approach and adaptive large neighborhood search heuristic to solve the problem. This method introduces a tabu search procedure, a learning mechanism, and four new removal operators. A real case and three generated datasets are used to evaluate its computational performance. The results demonstrate that the method can quickly obtain high-quality solutions.</p

    Responses of dioecious Populus to heavy metals: a meta-analysis

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    A total of 946 sets of comparative data were collected from 20 publications and a meta-analysis performed to evaluate the responses of growth, photosynthetic capacity, oxidative stress and antioxidants in Populus females and males under exposure to heavy metals, like Cu, Mn, Zn, Pb and Cd. It was found that heavy metals have negative effects on Populus growth and photosynthetic capacity, as the average total biomass, leaf biomass, stem biomass, root biomass and height decreased by 29.78%, 33.41%, 27.22%, 35.30% and 34.83%, respectively. Furthermore, total chl, Pn, gs, E, Ci decreased by 23.30%, 26.03%, 40.49%, 23.76% and 18.24%, respectively. In addition, heavy metals increased oxidative stress and antioxidant enzyme activities: the average values of TBARS, H2O2, \begin{document}O2−{\text{O}^-_2} \end{document} and MDA increased by 51.39%, 55.79%, 64.67% and 48.92%, respectively, and proline, APX, NPT, POD, CAT and SOD increased by 68.91%, 64.81%, 68.40%, 57.34%, 77.30% and 49.01%, respectively. However, there were sex-specific responses to heavy metals: females suffered more negative effects, as they had significantly greater decreases in root biomass, R/S ratio, height and total chl, and significantly smaller increases in NPT and POD activities than males. The present meta-analysis shows the responses of Populus females and males to heavy metals on a regional scale, which is crucial for understanding the patterns of sexual dimorphism and sex ratio biases in Populus with increasing heavy metal pollution in the future

    Exploration of the spatial relationship between Xi’an City and its mausoleums from the perspective of time evolution

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    The ancient City of Xi’an has a history of more than 7,000 years of civilization, more than 3,100 years of City development, and 1,100 years of capital construction. With the gradual development of urban areas, the number of imperial tombs in Xi’an has reached 72. These mausoleums are large in scale and valuable, yet they are influenced by the rapid development of present urbanization, cities, and mausoleum spaces. The development contradictions between cities and mausoleum spaces progressively become prominent and need to be handled urgently. This article utilizes spacetime as the base scale, GIS spatio-temporal analysis, field research (including aerial photographs of unmanned aerial vehicle (UAV) in the 8 years, 2015–2022), and Pearson analysis to explore the temporal and spatial evolution law between Xi’an’s urban space and the 55 mausoleums dominated by emperors of various dynasties. It was concluded that the nuclear density area distance layout of Xi’an City and the mausoleum is closely related to time and space. Since ancient times, there has always been a relationship between the Spatio-temporal development of Xi’an City and its mausoleums, and the nuclear density area distance layout of the mausoleums is intimately connected to the status and nature of Xi’an City. Currently, mausoleums are part of site protection. However, because of the large space of the mausoleum, the contradiction between the protection and utilization of mausoleum sites and the development of urban space is revealed. This paper hopes to provide urban planners and site protectors with ideas and data support for the Spatio-temporal development of cities and mausoleums and realize the integration of the protection and renewal of mausoleum sites into the path of urban design and planning

    Bilevel Model for Protection-Branch Measurements-Based Topology Attack Against DC and AC State Estimations

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    A topology attack, as a special class of false data injection attacks, tampers with topology information of a system to mislead the decision of the control center. This article conducts an in-depth study on topology attacks that aim to interfere with the judgment in topology information and pose potential damage by tampering with measurement data and protection information on branches, namely, protection-branch measurements-based topology attacks (PBT attacks). To achieve PBT attacks in actual networks, we study the protection settings and mechanisms in term of branches including transformers and transmission lines. Then, for the first time, we develop a bilevel model based on the protection configuration from the perspective of security-constrained economic dispatch. Meanwhile, since a bilevel model is constructed against dc state estimation, a conversion method in constructing attack vectors under PBT attacks against ac power system is proposed, which makes PBT attacks more suitable for actual power systems and more concealed. In a set of case studies on an IEEE 14-bus system, the simulation results verify the effectiveness of the model we proposed, analyze the vulnerability of network under PBT attacks, and then identify some critical branches that are defended to cope with PBT attacks. In addition, the comparison between PBT attacks and traditional cyber-overloaded attacks also shows a stronger threat of the studied attacks
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