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Modeling displacement flow inside a full-length casing string for well cementing

Petroleum Research 2024年第1期9卷 1-16页

作者： Hu Dai Ali Eslami Jason Schneider Gefei Liu Fred Schwering Pegasus Vertex Inc.USA Laval University Canada Sanjel Energy services Canada Athabasca Oil corporation Canada

While computer modeling of annular displacement efficiency is widely applied in cementing engineering,modeling the displacement flow inside a casing or drill string for cementing operations has received less *** predicting displacement efficiency inside a full-length pipe is desired by cementing engineers,the attempt of developing a model with both efficiency and accuracy faces *** to computer simulators for this purpose is *** with annular flow,the displacement flow inside pipe,although within a simpler geometry and without eccentricity effect,is not simpler in physics,modelling strategy and predictability,because a variety of flow patterns and flow instabilities can develop to create complicated fluid *** this paper,we present an integrated numerical model developed to simulate displacement flows inside a full-length pipe,which connects an existing annulus model to enable complete displacement simulations of cementing *** model uses three-dimensional grid to solve fluid concentrations with degrees of mixing,and incorporates flow instability detection and flow regime *** in cementing,the model accounts for effects of pumping rate,well inclination,pipe rotation,fluid densities,rheological parameters and *** computationally efficient model does not rely on high-resolution mesh as often required by conventional Computational Fluid Dynamics models,thus it is suitable to be implemented in a cementing software for daily use by well cementing *** methodology of the model is discussed in detail in this *** validate the model,we examine simulation results against experimental results obtained in our laboratory tests and CFD simulations;acceptable agreement is found under different testing *** also presented two case studies of real cementing jobs with cement evaluation logs compared to simulation results,showing that the model can predict consistent displacement efficie

关键词： Inside pipe displacement Displacement efficiency Numerical model Primary cementing Displacement flow

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Semantic segmentation-based semantic communication system for image transmission

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Digital Communications and Networks 2024年第3期10卷 519-527页

作者： Jiale Wu Celimuge Wu Yangfei Lin Tsutomu Yoshinaga Lei Zhong Xianfu Chen Yusheng Ji The University of Electro-Communication Tokyo182-8585Japan Toyota Motor corporation Tokyo112-8701Japan VTT Technical Research Centre of Finland OuluFinland National Institute of informatics(NII) Tokyo101-8430Japan

With the rapid development of artificial intelligence and the widespread use of the Internet of Things, semantic communication, as an emerging communication paradigm, has been attracting great interest. Taking image transmission as an example, from the semantic communication's view, not all pixels in the images are equally important for certain receivers. The existing semantic communication systems directly perform semantic encoding and decoding on the whole image, in which the region of interest cannot be identified. In this paper, we propose a novel semantic communication system for image transmission that can distinguish between Regions Of Interest (ROI) and Regions Of Non-Interest (RONI) based on semantic segmentation, where a semantic segmentation algorithm is used to classify each pixel of the image and distinguish ROI and RONI. The system also enables high-quality transmission of ROI with lower communication overheads by transmissions through different semantic communication networks with different bandwidth requirements. An improved metric θPSNR is proposed to evaluate the transmission accuracy of the novel semantic transmission network. Experimental results show that our proposed system achieves a significant performance improvement compared with existing approaches, namely, existing semantic communication approaches and the conventional approach without semantics.

关键词： Semantic Communication Semantic segmentation Image transmission Image compression Deep learning

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Hybrid Beamforming Design and Signal Processing with Fully-Connected Architecture for mmWave Integrated Sensing and Communications

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Journal of Communications and Information Networks 2024年第2期9卷 151-161页

作者： Hongyu Li Jun Gong Wenchi Cheng The 54th Research Institute of China Electronics Technology Group corporation Shijiazhuang 050080China State Key Laboratory of Integrated services Networks Xidian UniversityXi’an 710071China

Millimeter-wave (mmWave) is capable of achieving gigabit/second communication capacity and centimeter-level sensing accuracy and has become one of the main frequency bands for integrated sensing and communications (ISAC) research. Hybrid beamforming techniques have attracted much attention for solving the high path loss of mmWave and further reducing the hardware cost of the system. However, the related studies based on multicarrier and fully-connected hybrid architectures are still limited. For this reason,this paper investigates the orthogonal frequency division multiplexing (OFDM) based mmWave fully-connected hybrid architecture ISAC system to form a stable communication beam and dynamically varying sensing beam. In order to realize the aforementioned multifunctional beams, the hybrid beamformer design problem based on weighted error minimization of multicarrier is proposed and solved efficiently using the penalty dual decomposition (PDD) algorithm. Meanwhile, based on the echo model, the multicarrier multiple signal classification (MUSIC) algorithm for target angle of arrival estimation and the two-dimensional discrete Fourier transform(2D-DFT)algorithm for distance and velocity estimation are proposed, respectively. Numerical simulation results show that by adjusting the weighting factor,a flexible trade-off can be formed between the communication spectrum efficiency and the sensing accuracy error.

关键词： integrated sensing and communications hybrid beamforming fully-connected architecture millimeter-wave

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Understandings of Urban Sustainability in China:a Bibliometric Analysis Using Chinese Literatures

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Journal of Geodesy and Geoinformation Science 2024年第1期7卷 105-122页

作者： WU Shuang YUE Yang LI Xuesong Department of Urban informatics School of Architecture and Urban PlanningShenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Spatial Smart Sensing and services Guangdong Key Laboratory for Urban InformaticsShenzhen UniversityShenzhen 518060China.

Cities hold a critical responsibility for achieving the Sustainable Development Goals(SDGs)due to their high population density,extensive resource consumption,and significant economic *** examine the present state of understandings regarding urban sustainability(SDG 11:Sustainable Cities and Communities)within Chinese research communities,this study collected 15950 papers from 1994 to 2022 on the 12 indicators of SDG 11,from the China National Knowledge Infrastructure(CNKI),a hub of Chinese academic papers,that directly relate to *** research topics on SDG 11 were identified for each indicator using bibliometrics analysis *** high-frequency keywords and clusters of keywords over the last three decades reveal that existing studies primarily concentrated on the physical aspects,such as transportation and environment,while there is a lack of consideration of societal *** indicates a limited and biased understanding of the urban sustainability within the Chinese academic ***,it is crucial to prioritize the societal aspects in order to develop a research agenda that further advances urban sustainability.

关键词： urban sustainability SDG 11 bibliometric Chinese research communities

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Digital twin for Industrial Internet

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Fundamental Research 2024年第1期4卷 21-24页

作者： Yushuai Li Yan Zhang Department of informatics University of Oslo Oslo 0316Norway

Industrial Internet upgrades the traditional industrial manufacturing to digitization,networking and intellectualization era,which calls for brand-new technology *** a promising solution,the emergence Digital Twin(DT)offers enhanced digital mapping capability with strong feasibility,security,economic and intelligence,which fits well with the concept of Industrial *** this paper,we focus on establishing a new reference architecture of DT to support the development of Industrial *** is composed of three interdependent layers(i.e.,physical layer,DT layer and DT networks layer)and four critical attributes(i.e.,privacy,security,awareness and real-time).We illustrate our perspectives for the functionality and relationship of the three layers,and features and feasible solutions of the four *** those efforts,the proposed DT architecture can provide both smart manufacturing and networked services for Industrial Internet ***,we also illustrate the relevant and open ***,the conclusion and future perspective are pointed out.

关键词： Digital twin Industrial Internet Industry 4.0 Made in China 2025 Networked services

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Fine-grained grid computing model for Wi-Fi indoor localization in complex environments

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Journal of Electronic Science and Technology 2024年第1期22卷 42-52页

作者： Yan Liang Song Chen Xin Dong Tu Liu School of Computer Engineering Chengdu Technological UniversityChengdu611730China HAN Networks corporation Limited Beijing100094China

The fingerprinting-based approach using the wireless local area network(WLAN)is widely used for indoor ***,the construction of the fingerprint database is quite *** when the position of the access point(AP)or wall changes,updating the fingerprint database in real-time is *** appropriate indoor localization approach,which has a low implementation cost,excellent real-time performance,and high localization accuracy and fully considers complex indoor environment factors,is preferred in location-based services(LBSs)*** this paper,we proposed a fine-grained grid computing(FGGC)model to achieve decimeter-level localization *** points(RPs)are generated in the grid by the FGGC ***,the received signal strength(RSS)values at each RP are calculated with the attenuation factors,such as the frequency band,three-dimensional propagation distance,and walls in complex *** a result,the fingerprint database can be established automatically without manual measurement,and the efficiency and cost that the FGGC model takes for the fingerprint database are superior to previous *** proposed indoor localization approach,which estimates the position step by step from the approximate grid location to the fine-grained location,can achieve higher real-time performance and localization accuracy *** mean error of the proposed model is 0.36 m,far lower than that of previous ***,the proposed model is feasible to improve the efficiency and accuracy of Wi-Fi indoor *** also shows high-accuracy performance with a fast running speed even under a large-size *** results indicate that the proposed method can also be suitable for precise marketing,indoor navigation,and emergency rescue.

关键词： Fine-grained grid computing (FGGC) Indoor localization Path loss Random forest Reference points(RPs)

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Research and application of key technologies for data delivery in railway engineering design based on metadata

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High-Speed Railway 2024年第1期2卷 51-56页

作者： Xiangru Lyu Xunxiao Yin Kun Wang Yongwen Wei Institute of Computing Technologies China Academy of Railway Sciences Corporation LimitedBeijing 100081China

In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as the difficulty in fully realizing the value of design results,this paper proposes a design and implementation scheme for a railway engineering collaborative design *** railway engineering collaborative design platform mainly includes functional modules such as metadata management,design collaboration,design delivery management,model component library,model rendering services,and Building Information Modeling(BIM)application *** on this,research is conducted on multi-disciplinary parameterized collaborative design technology for railway engineering,infrastructure data management and delivery technology,and design multi-source data fusion and application *** railway engineering collaborative design platform is compared with other railway design software to further validate its advantages and advanced *** platform has been widely applied in multiple railway construction projects,greatly improving the design and project management efficiency.

关键词： Railway engineering Metadata Data delivery Collaborative designplatform Design results BIM services

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A Deep Dive into the Trajectory and Transformation of Fintech in Colombia Through the Case of PTM Colombia-A Secondary Publication

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Proceedings of Business and Economic Studies 2024年第2期7卷 234-244页

作者： Yanni Gabriel GuacanemeÁlvarez Catalina Medina Ardila Nadeska Gallardo Licháa Otilia Miladys Gil Hoyos University corporation of Sabaneta(Unisabaneta) SabanetaColombia Remington University corporation MedellínColombia

This research focuses on analyzing and understanding the evolution and impact of fintech companies in Colombia,using PTM Colombia as a case study,a company that has undergone a significant transformation from its beginnings as a provider of physical recharges to its current *** a comprehensive platform for digital financial *** current research uses a qualitative descriptive approach and emphasizes understanding the perceptions and experiences in the field of Fintech in Colombia,particularly in the case of PTM *** study revealed that adaptability and customer orientation have been fundamental in the evolution of PTM,allowing the company to expand its range of services by actively listening to the needs of its users and adjusting its strategies *** addition,an accelerated and diversified growth of Fintech will be observed in Colombia,particularly in sectors such as credit and payments,driven by a constantly advancing technological environment and a regulatory framework that,although it presents challenges,also offers opportunities for financial *** growth has impacted the traditional banking sector,which,instead of being replaced by Fintech,is finding new forms of collaboration and coexistence that benefit both parties and,above all,the end *** conclusion,the study highlights how Fintech in Colombia,represented by cases such as PTM,is redefining the financial landscape through the adoption of advanced technologies,collaboration with traditional banking,and strong customer orientation.

关键词： Financial technology Financial inclusion Fintech ecosystem Financial transformation

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Intelligent Solution System for Cloud Security Based on Equity Distribution:Model and Algorithms

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Computers, Materials & Continua 2024年第1期78卷 1461-1479页

作者： Sarah Mustafa Eljack Mahdi Jemmali Mohsen Denden Mutasim Al Sadig Abdullah M.Algashami Sadok Turki Department of Computer Science and Information College of Science at ZulfiMajmaah UniversityAl-Majmaah11952Saudi Arabia Department of Computer Science College of Computing and InformaticsUniversity of SharjahSharjahUnited Arab Emirates Higher Institute of Computer Science and Mathematics University of MonastirMonastir5000Tunisia Mars Laboratory University of SousseSousseTunisia Department of Logistic and Maintenance UFR MIM at MetzUniversity of LorraineMetzFrance Department of Computer and Information Technologies College of Telecommunicationand Information Riyadh CTITechnical and Vocational Training Corporation TVTCRiyadh12464Saudi Arabia Department of Computer Science Higher Institute of Applied Sciences of SousseSousse UniversitySousse4000Tunisia

In the cloud environment,ensuring a high level of data security is in high *** planning storage optimization is part of the whole security process in the cloud *** enables data security by avoiding the risk of data loss and data *** development of data flow scheduling approaches in the cloud environment taking security parameters into account is *** our work,we propose a data scheduling model for the cloud *** is made up of three parts that together help dispatch user data flow to the appropriate *** first component is the Collector Agent whichmust periodically collect information on the state of the network *** second one is the monitoring agent which must then analyze,classify,and make a decision on the state of the link and finally transmit this information to the *** third one is the scheduler who must consider previous information to transfer user data,including fair distribution and reliable *** should be noted that each part of the proposedmodel requires the development of its *** this article,we are interested in the development of data transfer algorithms,including fairness distribution with the consideration of a stable link *** algorithms are based on the grouping of transmitted files and the iterative *** proposed algorithms showthe performances to obtain an approximate solution to the studied problem which is an NP-hard(Non-Polynomial solution)*** experimental results show that the best algorithm is the half-grouped minimum excluding(HME),with a percentage of 91.3%,an average deviation of 0.042,and an execution time of 0.001 s.

关键词： Cyber-security cloud computing cloud security algorithms heuristics

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Real-time seismology for the 05/12/2008 Wenchuan earthquake of China: A retrospective view

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Science China Earth Sciences 2009年第2期52卷 155-165页

作者： Paul SOMMERVILLE United Research services corporation

The devastating 05/12/2008 Wenchuan earthquake (Mw7.9) in Sichuan Province of China showed very few precursory phenomena and occurred on a fault system once assigned to be of moderate long term seismic risk. Given the existing coverage of seismograph stations in Sichuan Province, real-time seis-mology could have been effective in avoiding some earthquake damage and helping post-earthquake emergency response. In a retrospective view, we demonstrated that the epicenter can be located with 20 km accuracy using just two broadband stations with three-component, which takes only about 10 s after the onset of the earthquake. Initial magnitude is estimated to be M7 with the Tc measurement over first 4 seconds of P waves. Better magnitude estimate can be obtained within 2 min by modeling Pnl waves for stations about 500 km away where the S waveforms are clipped. The rupture area is well revealed by teleseismically-recorded >M5 early aftershocks within two hours after the mainshock. Within a few hours, teleseismic body waves were inverted to derive a more detailed rupture process and the finite fault model can be readily used to calculate ground motions, thus providing vital information for rescue efforts in the case where no real-time strong motion records are available.

关键词： real-time seismology earthquake early warning strong ground motion rapid location

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