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Tree-Based Solution Frameworks for Predicting Tunnel Boring Machine Performance Using Rock Mass and Material Properties
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作者 Danial Jahed Armaghani Zida Liu +3 位作者 Hadi Khabbaz Hadi Fattahi Diyuan Li Mohammad Afrazi 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第12期2421-2451,共31页
Tunnel Boring Machines(TBMs)are vital for tunnel and underground construction due to their high safety and efficiency.Accurately predicting TBM operational parameters based on the surrounding environment is crucial fo... Tunnel Boring Machines(TBMs)are vital for tunnel and underground construction due to their high safety and efficiency.Accurately predicting TBM operational parameters based on the surrounding environment is crucial for planning schedules and managing costs.This study investigates the effectiveness of tree-based machine learning models,including Random Forest,Extremely Randomized Trees,Adaptive Boosting Machine,Gradient Boosting Machine,Extreme Gradient Boosting Machine(XGBoost),Light Gradient Boosting Machine,and CatBoost,in predicting the Penetration Rate(PR)of TBMs by considering rock mass and material characteristics.These techniques are able to provide a good relationship between input(s)and output parameters;hence,obtaining a high level of accuracy.To do that,a comprehensive database comprising various rock mass and material parameters,including Rock Mass Rating,Brazilian Tensile Strength,and Weathering Zone,was utilized for model development.The practical application of these models was assessed with a new dataset representing diverse rock mass and material properties.To evaluate model performance,ranking systems and Taylor diagrams were employed.CatBoost emerged as the most accurate model during training and testing,with R2 scores of 0.927 and 0.861,respectively.However,during validation,XGBoost demonstrated superior performance with an R2 of 0.713.Despite these variations,all tree-based models showed promising accuracy in predicting TBM performance,providing valuable insights for similar projects in the future. 展开更多
关键词 TBM performance penetration rate tunnel construction tree-based models rock mass and material properties
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Tree-Based Proactive Routing Protocol for Wireless Mesh Network 被引量:2
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作者 Ji Wenjiang Ma Jianfeng +1 位作者 Ma Zhuo Ran Youliang 《China Communications》 SCIE CSCD 2012年第1期25-33,共9页
Wireless Mesh Network (WMN) is seen as an effective Intemet access solution for dynamic wireless applications. For the low mobility of mesh routers in WMN, the backbone topography can be effectively maintained by pr... Wireless Mesh Network (WMN) is seen as an effective Intemet access solution for dynamic wireless applications. For the low mobility of mesh routers in WMN, the backbone topography can be effectively maintained by proactive routing protocol. Pre-proposals like Tree Based Routing (TBR) protocol and Root Driven Routing (RDR) protocol are so centralized that they make the gateway becorre a bottleneck which severely restricts the network performance. We proposed an Optimized Tree-based Routing (OTR) protocol that logically separated the proactive tree into pieces. Route is partly computed by the branches instead of root. We also discussed the operation of multipie Intemet gateways which is a main issue in WMN. The new proposal lightens the load in root, reduces the overhead and improves the throughput. Numerical analysis and simulation results confirm that the perforrmnce of WMN is improved and OTR is more suitable for large scale WMN. 展开更多
关键词 wireless mesh network 802. lls routing protocol tree-based routing
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Immunizations on small worlds of tree-based wireless sensor networks 被引量:1
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作者 李峤 张百海 +2 位作者 崔灵果 范衠 Athanasios V.Vasilakos 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期25-33,共9页
The sensor virus is a serious threat,as an attacker can simply send a single packet to compromise the entire sensor network.Epidemics become drastic with link additions among sensors when the small world phenomena occ... The sensor virus is a serious threat,as an attacker can simply send a single packet to compromise the entire sensor network.Epidemics become drastic with link additions among sensors when the small world phenomena occur.Two immunization strategies,uniform immunization and temporary immunization,are conducted on small worlds of tree-based wireless sensor networks to combat the sensor viruses.With the former strategy,the infection extends exponentially,although the immunization effectively reduces the contagion speed.With the latter strategy,recurrent contagion oscillations occur in the small world when the spatial-temporal dynamics of the epidemic are considered.The oscillations come from the small-world structure and the temporary immunization.Mathematical analyses on the small world of the Cayley tree are presented to reveal the epidemic dynamics with the two immunization strategies. 展开更多
关键词 epidemic immunization small world tree-based networks
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Anomaly detection on displacement rates and deformation pattern features using tree-based algorithm in Japan and Indonesia 被引量:1
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作者 Adi Wibowo Satriawan Rasyid Purnama +3 位作者 Cecep Pratama Leni Sophia Heliani David P.Sahara Sidik Tri Wibowo 《Geodesy and Geodynamics》 CSCD 2023年第2期150-162,共13页
Research on strain anomalies and large earthquakes based on temporal and spatial crustal activities has been rapidly growing due to data availability, especially in Japan and Indonesia. However, many research works us... Research on strain anomalies and large earthquakes based on temporal and spatial crustal activities has been rapidly growing due to data availability, especially in Japan and Indonesia. However, many research works used local-scale case studies that focused on a specific earthquake characteristic using knowledgedriven techniques, such as crustal deformation analysis. In this study, a data-driven-based analysis is used to detect anomalies using displacement rates and deformation pattern features extracted from daily global navigation satellite system(GNSS) data using a machine learning algorithm. The GNSS data with188 and 1181 continuously operating reference stations from Indonesia and Japan, respectively, are used to identify the anomaly of recent major earthquakes in the last two decades. Feature displacement rates and deformation patterns are processed in several window times with 2560 experiment scenarios to produce the best detection using tree-based algorithms. Tree-based algorithms with a single estimator(decision tree), ensemble bagging(bagging, random forest and Extra Trees), and ensemble boosting(AdaBoost, gradient boosting, LGBM, and XGB) are applied in the study. The experiment test using realtime scenario GNSSdailydatareveals high F1-scores and accuracy for anomaly detection using slope windowing 365 and 730 days of 91-day displacement rates and then 7-day deformation pattern features in tree-based algorithms. The results show the potential for medium-term anomaly detection using GNSS data without the need for multiple vulnerability assessments. 展开更多
关键词 ANOMALY GNSS Displacement rates Deformation pattern tree-based algorithm
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Classes of tree-based networks 被引量:1
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作者 Mareike Fischer Michelle Galla +2 位作者 Lina Herbst Yangjing Long Kristina Wicke 《Visual Computing for Industry,Biomedicine,and Art》 2020年第1期104-129,共26页
Recently,so-called tree-based phylogenetic networks have attracted considerable attention.These networks can be constructed from a phylogenetic tree,called the base tree,by adding additional edges.The primary aim of t... Recently,so-called tree-based phylogenetic networks have attracted considerable attention.These networks can be constructed from a phylogenetic tree,called the base tree,by adding additional edges.The primary aim of this study is to provide sufficient criteria for tree-basedness by reducing phylogenetic networks to related graph structures.Even though it is generally known that determining whether a network is tree-based is an NP-complete problem,one of these criteria,namely edge-basedness,can be verified in linear time.Surprisingly,the class of edgebased networks is closely related to a well-known family of graphs,namely,the class of generalized series-parallel graphs,and we explore this relationship in full detail.Additionally,we introduce further classes of tree-based networks and analyze their relationships. 展开更多
关键词 Phylogenetic tree Phylogenetic network tree-based network Edge-based network Chordal network Hamilton connected Hamiltonian path Generalized series-parallel graphs Series-parallel graphs
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Code Clone Detection Method Based on the Combination of Tree-Based and Token-Based Methods
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作者 Ryota Ami Hirohide Haga 《Journal of Software Engineering and Applications》 2017年第13期891-906,共16页
This article proposes the high-speed and high-accuracy code clone detection method based on the combination of tree-based and token-based methods. Existence of duplicated program codes, called code clone, is one of th... This article proposes the high-speed and high-accuracy code clone detection method based on the combination of tree-based and token-based methods. Existence of duplicated program codes, called code clone, is one of the main factors that reduces the quality and maintainability of software. If one code fragment contains faults (bugs) and they are copied and modified to other locations, it is necessary to correct all of them. But it is not easy to find all code clones in large and complex software. Much research efforts have been done for code clone detection. There are mainly two methods for code clone detection. One is token-based and the other is tree-based method. Token-based method is fast and requires less resources. However it cannot detect all kinds of code clones. Tree-based method can detect all kinds of code clones, but it is slow and requires much computing resources. In this paper combination of these two methods was proposed to improve the efficiency and accuracy of detecting code clones. Firstly some candidates of code clones will be extracted by token-based method that is fast and lightweight. Then selected candidates will be checked more precisely by using tree-based method that can find all kinds of code clones. The prototype system was developed. This system accepts source code and tokenizes it in the first step. Then token-based method is applied to this token sequence to find candidates of code clones. After extracting several candidates, selected source codes will be converted into abstract syntax tree (AST) for applying tree-based method. Some sample source codes were used to evaluate the proposed method. This evaluation proved the improvement of efficiency and precision of code clones detecting. 展开更多
关键词 Code Clone Token-Based DETECTION tree-based DETECTION TREE EDIT Distance
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Performance Assessment of a Real PV System Connected to a Low-Voltage Grid 被引量:1
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作者 Gaber Magdy Mostafa Metwally +1 位作者 Adel A.Elbaset Esam Zaki 《Energy Engineering》 EI 2024年第1期13-26,共14页
The generation of photovoltaic(PV)solar energy is increasing continuously because it is renewable,unlimited,and clean energy.In the past,generation systems depended on non-renewable sources such as oil,coal,and gas.Th... The generation of photovoltaic(PV)solar energy is increasing continuously because it is renewable,unlimited,and clean energy.In the past,generation systems depended on non-renewable sources such as oil,coal,and gas.Therefore,this paper assesses the performance of a 51 kW PV solar power plant connected to a low-voltage grid to feed an administrative building in the 6th of October City,Egypt.The performance analysis of the considered grid-connected PV system is carried out using power system simulator for Engineering(PSS/E)software.Where the PSS/E program,monitors and uses the power analyzer that displays the parameters and measures some parameters such as current,voltage,total power,power factor,frequency,and current and voltage harmonics,the used inverter from the type of grid inverter for the considered system.The results conclude that when the maximum solar radiation is reached,the maximum current can be obtained from the solar panels,thus obtaining the maximum power and power factor.Decreasing total voltage harmonic distortion,a current harmonic distortion within permissible limits using active harmonic distortion because this type is fast in processing up to 300 microseconds.The connection between solar stations and the national grid makes the system more efficient. 展开更多
关键词 Low-voltage grid photovoltaic(PV)system total harmonic distortion grid-connected PV system
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The Research of Role Tree-Based Access Control Model
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作者 陆虹 夏天 《Journal of Donghua University(English Edition)》 EI CAS 2010年第2期274-276,共3页
Towards the crossing and coupling permissions in tasks existed widely in many fields and considering the design of role view must rely on the activities of the tasks process,based on Role Based Accessing Control (RBAC... Towards the crossing and coupling permissions in tasks existed widely in many fields and considering the design of role view must rely on the activities of the tasks process,based on Role Based Accessing Control (RBAC) model,this paper put forward a Role Tree-Based Access Control (RTBAC) model. In addition,the model definition and its constraint formal description is also discussed in this paper. RTBAC model is able to realize the dynamic organizing,self-determination and convenience of the design of role view,and guarantee the least role permission when task separating in the mean time. 展开更多
关键词 Role Based Accessing Control (RBAC) Role tree-based Access Control (RTBAC) Models Constraints Permission
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A Statistical Analysis of Textual E-Commerce Reviews Using Tree-Based Methods
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作者 Jessica Kubrusly Ana Luiza Neves Thamires Louzada Marques 《Open Journal of Statistics》 2022年第3期357-372,共16页
With the increasing interest in e-commerce shopping, customer reviews have become one of the most important elements that determine customer satisfaction regarding products. This demonstrates the importance of working... With the increasing interest in e-commerce shopping, customer reviews have become one of the most important elements that determine customer satisfaction regarding products. This demonstrates the importance of working with Text Mining. This study is based on The Women’s Clothing E-Commerce Reviews database, which consists of reviews written by real customers. The aim of this paper is to conduct a Text Mining approach on a set of customer reviews. Each review was classified as either a positive or negative review by employing a classification method. Four tree-based methods were applied to solve the classification problem, namely Classification Tree, Random Forest, Gradient Boosting and XGBoost. The dataset was categorized into training and test sets. The results indicate that the Random Forest method displays an overfitting, XGBoost displays an overfitting if the number of trees is too high, Classification Tree is good at detecting negative reviews and bad at detecting positive reviews and the Gradient Boosting shows stable values and quality measures above 77% for the test dataset. A consensus between the applied methods is noted for important classification terms. 展开更多
关键词 Text Mining Supervised Classification tree-based Methods Classification Trees Random Forest Gradient Boosting XGBoost
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Grid System Analysis of Urban Flora of Bukhara City (Uzbekistan)
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作者 Abdulla M. Umedov Husniddin K. Esanov 《American Journal of Plant Sciences》 CAS 2024年第2期139-144,共6页
This article presents information on the study of the flora of Uzbekistan based on grid system mapping. The urban flora of the city of Bukhara was researched in it. As a result of research, the territory of Bukhara ci... This article presents information on the study of the flora of Uzbekistan based on grid system mapping. The urban flora of the city of Bukhara was researched in it. As a result of research, the territory of Bukhara city was divided into 85 indexes based on 1 × 1 km<sup>2</sup> grid mapping system. The diversity and density of species in the indexes are determined. The influence of anthropogenic factors on the diversity of species in the indexes is determined. 展开更多
关键词 Bukhara City Urban Flora INDEX grid Map System HERBARIUM Geoinformation
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RoGRUT: A Hybrid Deep Learning Model for Detecting Power Trapping in Smart Grids
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作者 Farah Mohammad Saad Al-Ahmadi Jalal Al-Muhtadi 《Computers, Materials & Continua》 SCIE EI 2024年第5期3175-3192,共18页
Electricity theft is a widespread non-technical issue that has a negative impact on both power grids and electricity users.It hinders the economic growth of utility companies,poses electrical risks,and impacts the hig... Electricity theft is a widespread non-technical issue that has a negative impact on both power grids and electricity users.It hinders the economic growth of utility companies,poses electrical risks,and impacts the high energy costs borne by consumers.The development of smart grids is crucial for the identification of power theft since these systems create enormous amounts of data,including information on client consumption,which may be used to identify electricity theft using machine learning and deep learning techniques.Moreover,there also exist different solutions such as hardware-based solutions to detect electricity theft that may require human resources and expensive hardware.Computer-based solutions are presented in the literature to identify electricity theft but due to the dimensionality curse,class imbalance issue and improper hyper-parameter tuning of such models lead to poor performance.In this research,a hybrid deep learning model abbreviated as RoGRUT is proposed to detect electricity theft as amalicious and non-malicious activity.The key steps of the RoGRUT are data preprocessing that covers the problem of class imbalance,feature extraction and final theft detection.Different advanced-level models like RoBERTa is used to address the curse of dimensionality issue,the near miss for class imbalance,and transfer learning for classification.The effectiveness of the RoGRUTis evaluated using the dataset fromactual smartmeters.A significant number of simulations demonstrate that,when compared to its competitors,the RoGRUT achieves the best classification results.The performance evaluation of the proposed model revealed exemplary results across variousmetrics.The accuracy achieved was 88%,with precision at an impressive 86%and recall reaching 84%.The F1-Score,a measure of overall performance,stood at 85%.Furthermore,themodel exhibited a noteworthyMatthew correlation coefficient of 78%and excelled with an area under the curve of 91%. 展开更多
关键词 Electricity theft smart grid RoBERTa GRU transfer learning
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A Long-Time-Step-Permitting Tracer Transport Model on the Regular Latitude–Longitude Grid
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作者 Jianghao LI Li DONG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第3期493-508,共16页
If an explicit time scheme is used in a numerical model, the size of the integration time step is typically limited by the spatial resolution. This study develops a regular latitude–longitude grid-based global three-... If an explicit time scheme is used in a numerical model, the size of the integration time step is typically limited by the spatial resolution. This study develops a regular latitude–longitude grid-based global three-dimensional tracer transport model that is computationally stable at large time-step sizes. The tracer model employs a finite-volume flux-form semiLagrangian transport scheme in the horizontal and an adaptively implicit algorithm in the vertical. The horizontal and vertical solvers are coupled via a straightforward operator-splitting technique. Both the finite-volume scheme's onedimensional slope-limiter and the adaptively implicit vertical solver's first-order upwind scheme enforce monotonicity. The tracer model permits a large time-step size and is inherently conservative and monotonic. Idealized advection test cases demonstrate that the three-dimensional transport model performs very well in terms of accuracy, stability, and efficiency. It is possible to use this robust transport model in a global atmospheric dynamical core. 展开更多
关键词 tracer transport numerical stability latitude–longitude grid
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Physics-Constrained Robustness Enhancement for Tree Ensembles Applied in Smart Grid
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作者 Zhibo Yang Xiaohan Huang +2 位作者 Bingdong Wang Bin Hu Zhenyong Zhang 《Computers, Materials & Continua》 SCIE EI 2024年第8期3001-3019,共19页
With the widespread use of machine learning(ML)technology,the operational efficiency and responsiveness of power grids have been significantly enhanced,allowing smart grids to achieve high levels of automation and int... With the widespread use of machine learning(ML)technology,the operational efficiency and responsiveness of power grids have been significantly enhanced,allowing smart grids to achieve high levels of automation and intelligence.However,tree ensemble models commonly used in smart grids are vulnerable to adversarial attacks,making it urgent to enhance their robustness.To address this,we propose a robustness enhancement method that incorporates physical constraints into the node-splitting decisions of tree ensembles.Our algorithm improves robustness by developing a dataset of adversarial examples that comply with physical laws,ensuring training data accurately reflects possible attack scenarios while adhering to physical rules.In our experiments,the proposed method increased robustness against adversarial attacks by 100%when applied to real grid data under physical constraints.These results highlight the advantages of our method in maintaining efficient and secure operation of smart grids under adversarial conditions. 展开更多
关键词 Tree ensemble robustness enhancement adversarial attack smart grid
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Assessment of Crop Yield in China Simulated by Thirteen Global Gridded Crop Models
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作者 Dezhen YIN Fang LI +3 位作者 Yaqiong LU Xiaodong ZENG Zhongda LIN Yanqing ZHOU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第3期420-434,共15页
Global gridded crop models(GGCMs) have been broadly applied to assess the impacts of climate and environmental change and adaptation on agricultural production. China is a major grain producing country, but thus far o... Global gridded crop models(GGCMs) have been broadly applied to assess the impacts of climate and environmental change and adaptation on agricultural production. China is a major grain producing country, but thus far only a few studies have assessed the performance of GGCMs in China, and these studies mainly focused on the average and interannual variability of national and regional yields. Here, a systematic national-and provincial-scale evaluation of the simulations by13 GGCMs [12 from the GGCM Intercomparison(GGCMI) project, phase 1, and CLM5-crop] of the yields of four crops(wheat, maize, rice, and soybean) in China during 1980–2009 was carried out through comparison with crop yield statistics collected from the National Bureau of Statistics of China. Results showed that GGCMI models generally underestimate the national yield of rice but overestimate it for the other three crops, while CLM5-crop can reproduce the national yields of wheat, maize, and rice well. Most GGCMs struggle to simulate the spatial patterns of crop yields. In terms of temporal variability, GGCMI models generally fail to capture the observed significant increases, but some can skillfully simulate the interannual variability. Conversely, CLM5-crop can represent the increases in wheat, maize, and rice, but works less well in simulating the interannual variability. At least one model can skillfully reproduce the temporal variability of yields in the top-10 producing provinces in China, albeit with a few exceptions. This study, for the first time, provides a complete picture of GGCM performance in China, which is important for GGCM development and understanding the reliability and uncertainty of national-and provincial-scale crop yield prediction in China. 展开更多
关键词 global gridded crop model historical crop yield China multi-model evaluation
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Study on Joint Method of 3D Acoustic Emission Source Localization Simplex and Grid Search Scanning
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作者 Liu Wei-jian Wang Hao-nan +4 位作者 Xiao Yang Hou Meng-jie Dong Sen-sen Zhang Zhi-zeng Lu Gao-ming 《Applied Geophysics》 SCIE CSCD 2024年第3期456-467,617,共13页
Acoustic emission(AE)source localization is a fundamental element of rock fracture damage imaging.To improve the efficiency and accuracy of AE source localization,this paper proposes a joint method comprising a three-... Acoustic emission(AE)source localization is a fundamental element of rock fracture damage imaging.To improve the efficiency and accuracy of AE source localization,this paper proposes a joint method comprising a three-dimensional(3D)AE source localization simplex method and grid search scanning.Using the concept of the geometry of simplexes,tetrahedral iterations were first conducted to narrow down the suspected source region.This is followed by a process of meshing the region and node searching to scan for optimal solutions,until the source location is determined.The resulting algorithm was tested using the artificial excitation source localization and uniaxial compression tests,after which the localization results were compared with the simplex and exhaustive methods.The results revealed that the localization obtained using the proposed method is more stable and can be effectively avoided compared with the simplex localization method.Furthermore,compared with the global scanning method,the proposed method is more efficient,with an average time of 10%–20%of the global scanning localization algorithm.Thus,the proposed algorithm is of great significance for laboratory research focused on locating rupture damages sustained by large-sized rock masses or test blocks. 展开更多
关键词 acoustic emission simplex form grid search scan locating the epicenter
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Virtual Power Plants for Grid Resilience: A Concise Overview of Research and Applications
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作者 Yijing Xie Yichen Zhang +2 位作者 Wei-Jen Lee Zongli Lin Yacov A.Shamash 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第2期329-343,共15页
The power grid is undergoing a transformation from synchronous generators(SGs) toward inverter-based resources(IBRs). The stochasticity, asynchronicity, and limited-inertia characteristics of IBRs bring about challeng... The power grid is undergoing a transformation from synchronous generators(SGs) toward inverter-based resources(IBRs). The stochasticity, asynchronicity, and limited-inertia characteristics of IBRs bring about challenges to grid resilience. Virtual power plants(VPPs) are emerging technologies to improve the grid resilience and advance the transformation. By judiciously aggregating geographically distributed energy resources(DERs) as individual electrical entities, VPPs can provide capacity and ancillary services to grid operations and participate in electricity wholesale markets. This paper aims to provide a concise overview of the concept and development of VPPs and the latest progresses in VPP operation, with the focus on VPP scheduling and control. Based on this overview, we identify a few potential challenges in VPP operation and discuss the opportunities of integrating the multi-agent system(MAS)-based strategy into the VPP operation to enhance its scalability, performance and resilience. 展开更多
关键词 Climate change renewable energy resources RESILIENCE smart grids virtual power plants(VPPs)
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Novel cyber-physical collaborative detection and localization method against dynamic load altering attacks in smart energy grids
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作者 Xinyu Wang Xiangjie Wang +2 位作者 Xiaoyuan Luo Xinping Guan Shuzheng Wang 《Global Energy Interconnection》 EI CSCD 2024年第3期362-376,共15页
Owing to the integration of energy digitization and artificial intelligence technology,smart energy grids can realize the stable,efficient and clean operation of power systems.However,the emergence of cyber-physical a... Owing to the integration of energy digitization and artificial intelligence technology,smart energy grids can realize the stable,efficient and clean operation of power systems.However,the emergence of cyber-physical attacks,such as dynamic load-altering attacks(DLAAs)has introduced great challenges to the security of smart energy grids.Thus,this study developed a novel cyber-physical collaborative security framework for DLAAs in smart energy grids.The proposed framework integrates attack prediction in the cyber layer with the detection and localization of attacks in the physical layer.First,a data-driven method was proposed to predict the DLAA sequence in the cyber layer.By designing a double radial basis function network,the influence of disturbances on attack prediction can be eliminated.Based on the prediction results,an unknown input observer-based detection and localization method was further developed for the physical layer.In addition,an adaptive threshold was designed to replace the traditional precomputed threshold and improve the detection performance of the DLAAs.Consequently,through the collaborative work of the cyber-physics layer,injected DLAAs were effectively detected and located.Compared with existing methodologies,the simulation results on IEEE 14-bus and 118-bus power systems verified the superiority of the proposed cyber-physical collaborative detection and localization against DLAAs. 展开更多
关键词 Smart energy grids Cyber-physical system Dynamic load altering attacks Attack prediction Detection and localization
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Intelligent Power Grid Load Transferring Based on Safe Action-Correction Reinforcement Learning
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作者 Fuju Zhou Li Li +3 位作者 Tengfei Jia Yongchang Yin Aixiang Shi Shengrong Xu 《Energy Engineering》 EI 2024年第6期1697-1711,共15页
When a line failure occurs in a power grid, a load transfer is implemented to reconfigure the network by changingthe states of tie-switches and load demands. Computation speed is one of the major performance indicator... When a line failure occurs in a power grid, a load transfer is implemented to reconfigure the network by changingthe states of tie-switches and load demands. Computation speed is one of the major performance indicators inpower grid load transfer, as a fast load transfer model can greatly reduce the economic loss of post-fault powergrids. In this study, a reinforcement learning method is developed based on a deep deterministic policy gradient.The tedious training process of the reinforcement learning model can be conducted offline, so the model showssatisfactory performance in real-time operation, indicating that it is suitable for fast load transfer. Consideringthat the reinforcement learning model performs poorly in satisfying safety constraints, a safe action-correctionframework is proposed to modify the learning model. In the framework, the action of load shedding is correctedaccording to sensitivity analysis results under a small discrete increment so as to match the constraints of line flowlimits. The results of case studies indicate that the proposed method is practical for fast and safe power grid loadtransfer. 展开更多
关键词 Load transfer reinforcement learning electrical power grid safety constraints
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A U-Shaped Network-Based Grid Tagging Model for Chinese Named Entity Recognition
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作者 Yan Xiang Xuedong Zhao +3 位作者 Junjun Guo Zhiliang Shi Enbang Chen Xiaobo Zhang 《Computers, Materials & Continua》 SCIE EI 2024年第6期4149-4167,共19页
Chinese named entity recognition(CNER)has received widespread attention as an important task of Chinese information extraction.Most previous research has focused on individually studying flat CNER,overlapped CNER,or d... Chinese named entity recognition(CNER)has received widespread attention as an important task of Chinese information extraction.Most previous research has focused on individually studying flat CNER,overlapped CNER,or discontinuous CNER.However,a unified CNER is often needed in real-world scenarios.Recent studies have shown that grid tagging-based methods based on character-pair relationship classification hold great potential for achieving unified NER.Nevertheless,how to enrich Chinese character-pair grid representations and capture deeper dependencies between character pairs to improve entity recognition performance remains an unresolved challenge.In this study,we enhance the character-pair grid representation by incorporating both local and global information.Significantly,we introduce a new approach by considering the character-pair grid representation matrix as a specialized image,converting the classification of character-pair relationships into a pixel-level semantic segmentation task.We devise a U-shaped network to extract multi-scale and deeper semantic information from the grid image,allowing for a more comprehensive understanding of associative features between character pairs.This approach leads to improved accuracy in predicting their relationships,ultimately enhancing entity recognition performance.We conducted experiments on two public CNER datasets in the biomedical domain,namely CMeEE-V2 and Diakg.The results demonstrate the effectiveness of our approach,which achieves F1-score improvements of 7.29 percentage points and 1.64 percentage points compared to the current state-of-the-art(SOTA)models,respectively. 展开更多
关键词 Chinese named entity recognition character-pair relation classification grid tagging U-shaped segmentation network
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Evaluation of Moving Grid Adjustment (MGA) Method in Field Variation Control
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作者 Jixiang Wu Johnie N. Jenkins Jack C. McCarty 《Open Journal of Statistics》 2024年第5期450-466,共17页
Spatial variation is often encountered when large scale field trials are conducted which can result in biased estimation or prediction of treatment (i.e. genotype) values. An effective removal of spatial variation is ... Spatial variation is often encountered when large scale field trials are conducted which can result in biased estimation or prediction of treatment (i.e. genotype) values. An effective removal of spatial variation is needed to ensure unbiased estimation or prediction and thus increase the accuracy of field data evaluation. A moving grid adjustment (MGA) method, which was proposed by Technow, was evaluated through Monte Carlo simulation for its statistical properties regarding field spatial variation control. Our simulation results showed that the MGA method can effectively account for field spatial variation if it does exist;however, this method will not change phenotype results if field spatial variation does not exist. The MGA method was applied to a large-scale cotton field trial data set with two representative agronomic traits: lint yield (strong field spatial pattern) and lint percentage (no field spatial pattern). The results suggested that the MGA method was able to effectively separate the spatial variation including blocking effects from random error variation for lint yield while the adjusted data remained almost identical to the original phenotypic data. With application of the MGA method, the estimated variance for residuals was significantly reduced (62.2% decrease) for lint yield while more genetic variation (29.7% increase) was detected compared to the original data analysis subject to the conventional randomized complete block design analysis. On the other hand, the results were almost identical for lint percentage with and without the application of the MGA method. Therefore, the MGA method can be a useful addition to enhance data analysis when field spatial pattern exists. 展开更多
关键词 Spatial Variation Linear Mixed Model Approach Experimental Design Moving grid Adjustment Crop Trial
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