Distributed Topology Control With Lifetime Extension Based on Non-Cooperative Game for Wireless Sensor Networks

Mengmeng Xu,Qinghai Yang,Kyung Sup Kwak IEEE 2016 IEEE SENSORS JOURNAL Vol.16 No.9

<P>In a large and complex distributed sensor network, the individual sensor directly communicates only with its neighboring sensors. Despite being restricted to such local communications, the network itself should be self-organizing to maintain certain desirable properties, such as network connectivity and lifetime maximization. Topology control is a technique to determine the optimal transmit parameters for each sensor, such that the network topology has the best possible network performance. In this paper, we investigate a dynamic topology control scheme to improve the network lifetime for wireless sensor networks in the presence of selfish sensors. A non-cooperative game aided topology control approach is developed for designing energy-efficient and energy balanced network topologies dynamically. Each sensor in the topology control game tries to minimize its unwillingness for constructing a connected network according to its residual energy and transmit power. We prove the existence of Nash equilibrium (NE) and demonstrate that the NE is Pareto optimal as well. Specifically, a fully distributed algorithm-topology control with lifetime extension (TCLE)-is proposed to construct dynamic network topologies. The topologies derived by TCLE algorithm can improve the network lifetime significantly as compared with existing algorithms. Simulations demonstrate the efficiency of our TCLE algorithm.</P>

Energy-Connectivity Tradeoff through Topology Control in Wireless Ad Hoc Networks

Mengmeng Xu,Qinghai Yang,곽경섭 한국전자통신연구원 2017 ETRI Journal Vol.39 No.1

In this study, we investigate topology control as a means of obtaining the best possible compromise between the conflicting requirements of reducing energy consumption and improving network connectivity. A topology design algorithm capable of producing network topologies that minimize energy consumption under a minimum-connectivity constraint is presented. To this end, we define a new topology metric, called connectivity efficiency, which is a function of both algebraic connectivity and the transmit power level. Based on this metric, links that require a high transmit power but only contribute to a small fraction of the network connectivity are chosen to be removed. A connectivity-efficiency-based topology control (CETC) algorithm then assigns a transmit power level to each node. The network topology derived by the proposed CETC heuristic algorithm is shown to attain a better tradeoff between energy consumption and network connectivity than existing algorithms. Simulation results demonstrate the efficiency of the CECT algorithm.

Effectively promote catalytic performance by adjusting W/Fe molar ratio of FeWx/Ce0.68Zr0.32O2 monolithic catalyst for NH3-SCR

Haidi Xu,Yuanshan Li,Baoqiang Xu,Yi Cao,Xi Feng,Mengmeng Sun,Maochu Gong,Yaoqiang Chen 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.36 No.-

FeWx/Ce0.68Zr0.32O2 (x = 0, 0.35, 0.7, 1.03, 1.38) catalysts with different molar ratios (x) of W/Fe wereprepared for NH3-SCR. The experimental results showed that catalytic performances of catalysts wereobviously improved by adjusting the molar ratio of W/Fe. FeW1.03/Ce0.68Zr0.32O2 catalyst with W/Fe of1.03 displayed the best catalytic performance, it could obtain higher than 95% NOx conversion and nearly100% N2 selectivity in the temperature range of 250–435 8C. The characterization results indicated thatmore active species of Fe3+, chemical adsorbed oxygen species and surface acid sites would togethercontribute to the excellent NH3-SCR performance of FeW1.03/Ce0.68Zr0.32O2 catalyst.

Preparation and Investigation of Fe3O4@rGO/CNF Foams for Electromagnetic Interference Shielding

Mengmeng Li,Qiuyu Xu,Wei Jiang,Amjad Farooq,Yirui Qi,Lifang Liu 한국섬유공학회 2023 Fibers and polymers Vol.24 No.2

Herein, Fe3O4nanoparticles and graphene oxide (GO) are compounded first, followed by the addition of cellulose nanofiber(CNF) and l-ascorbic acid, to obtain Fe3O4@reduced graphene oxide (rGO)/CNF foams via the freeze-drying method. Theelectrical conductivity and magnetism of as-prepared foams were improved due to the presence of rGO and Fe3O4,whichis suitable for electromagnetic interference (EMI) shielding material. The results exhibit that Fe3O4@rGO/CNF foams allpossess a porous structure, and the optimized foam shows an EMI shielding effectiveness value of ~ 23 dB in the X-band. The good EMI shielding performance of the Fe3O4@rGO/CNF foam originates from the synergy of its composition andstructure. This work could provide a reference for the design and fabrication of novel EMI shielding materials.

EXPLORING CONSUMER'S PREFERENCE ON AI AGENTS FOR HIGH-TECH PRODUCTS: THE ROLE OF TEMPORAL PSYCHOLOGICAL DISTANCE

Yuandong Xu,Mengmeng Zhang,Huanzhang Wang 글로벌지식마케팅경영학회 2023 Global Marketing Conference Vol.2023 No.07

AI recommendation service is adopted in consumption consulting such as high-tech and fashion consumption (Thapliyal & Ahuj, 2021). Now, for high-tech and fashion products, the advance selling strategy is widely adopted. Thus, this study targets to detective the consumers’ preference toward AI agents comparing human agents under advance selling and spot selling. The independent variable of this study is consumption type: Pre-sale Products vs. Spot Products. Pre-sale Products are quite popular currently, especially technological products. Construal-level theory (CLT) offers a valuable framework to explain the mechanisms that trigger evaluations, predictions, and behaviors by linking the degree of mental abstraction (the construal level) to psychological distance (Trope & Liberman, 2000; 2003; 2010). Four dimensions including temporal, special, social, and probability distance are argued to present the psychological distance (Trope et al., 2007). Liberman et al. (2022) discuss the time distance and argue the distant-future events are represented in a more abstract, structured, high-level manner than near-future events. Kim & Duhachek (2020) draw on a dimension of persuasion by AI agents to posit that AI agents are perceived as low-construal agents because of the fact that people hold a lay theory that AI agents do not have superordinate goals and cannot learn from their experiences or possess consciousness like humans do. Consequently, they find that individuals perceive greater appropriateness and are more persuaded when an AI agent’s persuasive messages highlight low-construal as opposed to high-construal features. Moreover, consumers prefer abstract information related to a certain product rather than concrete information when a purchase is to take place in the distant future or when construal levels are high (Hernandez et al., 2015). Thus, this research hypothesizes: When consumers buy pre-sale products (vs. spot products), human agents will be the more favorable service provider than AI agents since the consumer is under a high level of construal. This research proposes to adopt a 2 (Advance Selling vs. Spot Selling) x 2 (Short Psychological Distance vs. Far Psychological Distance) x 2 (AI Agents vs. Human Agents) between groups experimental study to test the main effects and mechanism (H1). Furthermore, this study would identify the key moderating effects to discuss the boundary effects of the mechanism for establishing marketing strategies with AI services for managers.

Green Hydrothermal Synthesis of Fluorescent Carbon Dots from Glucose and Taurine for Fe3+ and pH Sensing

Yanmin Xu,Lihe Yan,Mengmeng Yue,Yang Yu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.1

Carbon nanodots (C-dots), as a class of heavy-metal-free fluorescent nonmaterial have drawn increasing attention due to their strong photoluminescence (PL), good biocompatibility and low toxicity. Herein, we synthesize nontoxic fluorescent C-dots by hydrothermal treatment of the mixture of glucose and taurine, in which process the formation and the surface passivation of C-dots take place simultaneously. The influence of reaction temperature, reaction time and feed ratio of glucose to taurine on the PL property of C-dots is studied. As the C-dots exhibit sensitive pH and iron ion dependent PL property, they can be used for pH and Fe3+ sensing in solutions.

miR-30c regulates proliferation, apoptosis and differentiation via the Shh signaling pathway in P19 cells

Xuehua Liu,Mengmeng Li,Yuzhu Peng,Xiaoshan Hu,Jing Xu,Shasha Zhu,Zhangbin Yu,Shuping Han 생화학분자생물학회 2016 Experimental and molecular medicine Vol.48 No.-

MicroRNAs (miRNAs) are small, non-coding single-stranded RNAs that suppress protein expression by binding to the 3′ untranslated regions of their target genes. Many studies have shown that miRNAs have important roles in congenital heart diseases (CHDs) by regulating gene expression and signaling pathways. We previously found that miR-30c was highly expressed in the heart tissues of aborted embryos with ventricular septal defects. Therefore, this study aimed to explore the effects of miR-30c in CHDs. miR-30c was overexpressed or knocked down in P19 cells, a myocardial cell model that is widely used to study cardiogenesis. We found that miR-30c overexpression not only increased cell proliferation by promoting cell entry into S phase but also suppressed cell apoptosis. In addition, we found that miR-30c inhibited dimethyl sulfoxide-induced differentiation of P19 cells. miR-30c knockdown, in contrast, inhibited cell proliferation and increased apoptosis and differentiation. The Sonic hedgehog (Shh) signaling pathway is essential for normal embryonic development. Western blotting and luciferase assays revealed that Gli2, a transcriptional factor that has essential roles in the Shh signaling pathway, was a potential target gene of miR-30c. Ptch1, another important player in the Shh signaling pathway and a transcriptional target of Gli2, was downregulated by miR-30c overexpression and upregulated by miR-30c knockdown. Collectively, our study revealed that miR-30c suppressed P19 cell differentiation by inhibiting the Shh signaling pathway and altered the balance between cell proliferation and apoptosis, which may result in embryonic cardiac malfunctions.

全球价值链嵌入促进中国经济高质量发展了吗?: 基于GVC嵌入对全要素生产率增长效应的实证检验

许冬兰 ( Donglan Xu ),戴萌萌 ( Mengmeng Dai ),赵倩 ( Qian Zhao ) 성균관대학교 성균중국연구소 2019 중국사회과학논총 Vol.1 No.2

以全球价值链嵌入(GVC)形式融入国际分工,使中国经济的质量、效率和动力都发生了巨大变化。鉴于此,本文基于增加值视角利用国际投入产出模型测算了中国全球价值链嵌入程度,然后利用动态GMM模型实证考察了GVC嵌入程度对中国制造业全要素生产率(TFP)的影响效应及内在机制,以此揭示GVC嵌入对中国高质量发展的作用效果。研究表明:GVC嵌入程度的加深显著促进了中国TFP的提升, 而这种提升主要是通过价值链对技术进步、规模效率的显著正向影响来实现的,对技术效率的影响却不显著。可知,全球价值链嵌入主要通过技术溢出效应和规模经济效应带动了中国TFP的提升,进而带来推动经济高质量发展的作用效果。此外,研发投入、国际市场参与度、出口密集度等因素也对TFP产生显著的正向影响。 Integrating into the international division of labor in the form of embedding Global Value Chain has resulted in the tremendous change for the quality efficiency and power of China’s economy. Based on the perspective of added value, this research employed the International Input-Output Model to calculate China’s participation level in global value chain (GVC). And then It used the dynamic Generalized method of moments (GMM) model to examine the influence and inherent mechanism of the participation level in GVC on the TFP of manufacturing industry in order to reveal the effect of Global Value Chain embedding on China’s high-quality development. It is found that the increasing of the participation level in GVC has significantly stimulated the growth of China’s TFP, and the participation level in GVC positively affects the TFP through technical progress and scale efficiency instead of technical efficiency. Therefore, the participation level in GVC drives the upgrading of China’s TFP through technology spillover effect and scale economies effect, thus resulting in the development of economy with high quality. In addition, it should be noted that R&D, international market participation, and export’s intensity can also impose significantly positive impact on the TFP.

magnetostratigraphy, 26Al-10Be, Yx02 borehole, tectonic evolution, Daxing Uplift, Beijing Sub-plain

Fubing He,Xiwei Xu,Fang Tian,Zhenhua Liu,Yueze Zhang,Lingyan Bai,Yubin Cui,Kai Wang,Wenzhi Niu,Jingbo Ni,Xiaoyong Liu,Mengmeng Cao 한국지질과학협의회 2024 Geosciences Journal Vol.28 No.2

The buried Daxing Uplift connects the Beijing Sag and Dachang Sag, which is the critical tectonic unit for understanding the structural evolution of the Beijing Sub-plain and its linkages to regional tectonics. This study combines paleomagnetic, 26Al-10Be isochron dates and sedimentary analyses from a new borehole (Yx02) in the northeastern Beijing Sub-plain to shed fresh light on regional tectonic processes and the sedimentary history since the Pliocene. The main findings are as follows: (1) the Daxing Uplift had formed three depositional episodes: alluvial-fan, lacustrine-delta, and alluvial-fan sedimentation since the Cenozoic; (2) The borehole records the Brunhes, Gauss normal chron, and the Matuyama, Gilbert reversed chron in the Daxing Uplift, the corresponding depths are 0–148.9 m, 148.9–315.0 m, 315.0–520.5 m and 520.5–650 m; (3) An important tectonic event started in ~4.3 Ma, disintegrated NE-trending basin and range terrain, reactivated the NW-trending Nankou-Sunhe fault, and formed Shunyi fault in Beijing Sub-plain. Sedimentation occurs exclusively in the Beijing Sag and the northeastern Daxing Uplift during ~4.3–1.77 Ma; (4) During ~1.77–1.07 Ma, a transition from an extension to a strike-slip occurred, and is described not only in a progressively higher increase of the overall deposition rate, but also in a decrease of the relative deposition disparity between sags and uplifts. Since then, the Beijing Sub-plain has been shaped, associated with an overall subsidence depression in the Bohai Bay Basin. This work enhances our understanding of the formation and evolution of the Beijing Sub-plain, the division of tectonic episodes, and the initiation time of the latest tectonic movement in the break-up region, North China Craton, since the Neogene.

Research on the Law of Stress Development Along Backfi lling Process Between Crest and Valley of Buried Corrugated Steel Pipe Culverts

Baodong Liu,Haibo Sun,Weibo Xu,Yafei Shi,Beichen Zhang,Mengmeng Yao 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.1

Although buried corrugated steel pipe culverts have been studied intensively in the past decades, the stress development law between crest and valley during backfi lling process is still not analyzed suffi ciently, which is an important technical diffi culty for the construction of this kind of structures. In this paper, a three-dimensional fi nite element model (FEM) is developed to simulate the behavior of buried pipes during construction and the stress development law within a wavelength (curvature of corrugated pipe) ranging at the crown and the spring-line inside the pipe is proposed. Based on the measured stress data of a porous continuous corrugated steel plate pipe-arch culvert, the proposed three-dimensional FEM and stress development law are verifi ed. The results show that the stress variations in a wavelength range of corrugated steel plate are trigonometric curves. With the increase of the backfi lling height, the ratio of the stress at the crest or valley, to that of the spring-line is reduced, while the axial force is increased. The absolute value of the bending moment decays and the pipe culvert tends to be ring compression as the backfi lling height increased. The study verifi es the "ring compression theory" and the necessity of the minimum burial depth in design. Meanwhile, some design and construction guidelines which is necessary for the structure safety during backfi lling process are provided for buried corrugated steel pipe culverts.