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User Churn Prediction Hierarchical Model Based on Graph Attention Convolutional Neural Networks
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作者 Mei Miao Tang Miao Zhou Long 《China Communications》 SCIE CSCD 2024年第7期169-185,共17页
The telecommunications industry is becoming increasingly aware of potential subscriber churn as a result of the growing popularity of smartphones in the mobile Internet era,the quick development of telecommunications ... The telecommunications industry is becoming increasingly aware of potential subscriber churn as a result of the growing popularity of smartphones in the mobile Internet era,the quick development of telecommunications services,the implementation of the number portability policy,and the intensifying competition among operators.At the same time,users'consumption preferences and choices are evolving.Excellent churn prediction models must be created in order to accurately predict the churn tendency,since keeping existing customers is far less expensive than acquiring new ones.But conventional or learning-based algorithms can only go so far into a single subscriber's data;they cannot take into consideration changes in a subscriber's subscription and ignore the coupling and correlation between various features.Additionally,the current churn prediction models have a high computational burden,a fuzzy weight distribution,and significant resource economic costs.The prediction algorithms involving network models currently in use primarily take into account the private information shared between users with text and pictures,ignoring the reference value supplied by other users with the same package.This work suggests a user churn prediction model based on Graph Attention Convolutional Neural Network(GAT-CNN)to address the aforementioned issues.The main contributions of this paper are as follows:Firstly,we present a three-tiered hierarchical cloud-edge cooperative framework that increases the volume of user feature input by means of two aggregations at the device,edge,and cloud layers.Second,we extend the use of users'own data by introducing self-attention and graph convolution models to track the relative changes of both users and packages simultaneously.Lastly,we build an integrated offline-online system for churn prediction based on the strengths of the two models,and we experimentally validate the efficacy of cloudside collaborative training and inference.In summary,the churn prediction model based on Graph Attention Convolutional Neural Network presented in this paper can effectively address the drawbacks of conventional algorithms and offer telecom operators crucial decision support in developing subscriber retention strategies and cutting operational expenses. 展开更多
关键词 cloud-edge cooperative framework GAT-CNN self-attention and graph convolution models subscriber churn prediction
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Weighted Forwarding in Graph Convolution Networks for Recommendation Information Systems
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作者 Sang-min Lee Namgi Kim 《Computers, Materials & Continua》 SCIE EI 2024年第2期1897-1914,共18页
Recommendation Information Systems(RIS)are pivotal in helping users in swiftly locating desired content from the vast amount of information available on the Internet.Graph Convolution Network(GCN)algorithms have been ... Recommendation Information Systems(RIS)are pivotal in helping users in swiftly locating desired content from the vast amount of information available on the Internet.Graph Convolution Network(GCN)algorithms have been employed to implement the RIS efficiently.However,the GCN algorithm faces limitations in terms of performance enhancement owing to the due to the embedding value-vanishing problem that occurs during the learning process.To address this issue,we propose a Weighted Forwarding method using the GCN(WF-GCN)algorithm.The proposed method involves multiplying the embedding results with different weights for each hop layer during graph learning.By applying the WF-GCN algorithm,which adjusts weights for each hop layer before forwarding to the next,nodes with many neighbors achieve higher embedding values.This approach facilitates the learning of more hop layers within the GCN framework.The efficacy of the WF-GCN was demonstrated through its application to various datasets.In the MovieLens dataset,the implementation of WF-GCN in LightGCN resulted in significant performance improvements,with recall and NDCG increasing by up to+163.64%and+132.04%,respectively.Similarly,in the Last.FM dataset,LightGCN using WF-GCN enhanced with WF-GCN showed substantial improvements,with the recall and NDCG metrics rising by up to+174.40%and+169.95%,respectively.Furthermore,the application of WF-GCN to Self-supervised Graph Learning(SGL)and Simple Graph Contrastive Learning(SimGCL)also demonstrated notable enhancements in both recall and NDCG across these datasets. 展开更多
关键词 Deep learning graph neural network graph convolution network graph convolution network model learning method recommender information systems
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TG-SMR:AText Summarization Algorithm Based on Topic and Graph Models 被引量:1
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作者 Mohamed Ali Rakrouki Nawaf Alharbe +1 位作者 Mashael Khayyat Abeer Aljohani 《Computer Systems Science & Engineering》 SCIE EI 2023年第4期395-408,共14页
Recently,automation is considered vital in most fields since computing methods have a significant role in facilitating work such as automatic text summarization.However,most of the computing methods that are used in r... Recently,automation is considered vital in most fields since computing methods have a significant role in facilitating work such as automatic text summarization.However,most of the computing methods that are used in real systems are based on graph models,which are characterized by their simplicity and stability.Thus,this paper proposes an improved extractive text summarization algorithm based on both topic and graph models.The methodology of this work consists of two stages.First,the well-known TextRank algorithm is analyzed and its shortcomings are investigated.Then,an improved method is proposed with a new computational model of sentence weights.The experimental results were carried out on standard DUC2004 and DUC2006 datasets and compared to four text summarization methods.Finally,through experiments on the DUC2004 and DUC2006 datasets,our proposed improved graph model algorithm TG-SMR(Topic Graph-Summarizer)is compared to other text summarization systems.The experimental results prove that the proposed TG-SMR algorithm achieves higher ROUGE scores.It is foreseen that the TG-SMR algorithm will open a new horizon that concerns the performance of ROUGE evaluation indicators. 展开更多
关键词 Natural language processing text summarization graph model topic model
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Graph-Based Chinese Word Sense Disambiguation with Multi-Knowledge Integration 被引量:1
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作者 Wenpeng Lu Fanqing Meng +4 位作者 Shoujin Wang Guoqiang Zhang Xu Zhang Antai Ouyang Xiaodong Zhang 《Computers, Materials & Continua》 SCIE EI 2019年第7期197-212,共16页
Word sense disambiguation(WSD)is a fundamental but significant task in natural language processing,which directly affects the performance of upper applications.However,WSD is very challenging due to the problem of kno... Word sense disambiguation(WSD)is a fundamental but significant task in natural language processing,which directly affects the performance of upper applications.However,WSD is very challenging due to the problem of knowledge bottleneck,i.e.,it is hard to acquire abundant disambiguation knowledge,especially in Chinese.To solve this problem,this paper proposes a graph-based Chinese WSD method with multi-knowledge integration.Particularly,a graph model combining various Chinese and English knowledge resources by word sense mapping is designed.Firstly,the content words in a Chinese ambiguous sentence are extracted and mapped to English words with BabelNet.Then,English word similarity is computed based on English word embeddings and knowledge base.Chinese word similarity is evaluated with Chinese word embedding and HowNet,respectively.The weights of the three kinds of word similarity are optimized with simulated annealing algorithm so as to obtain their overall similarities,which are utilized to construct a disambiguation graph.The graph scoring algorithm evaluates the importance of each word sense node and judge the right senses of the ambiguous words.Extensive experimental results on SemEval dataset show that our proposed WSD method significantly outperforms the baselines. 展开更多
关键词 Word sense disambiguation graph model multi-knowledge integration word similarity
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Thermal-hydraulic modeling and analysis of hydraulic system by pseudo-bond graph 被引量:2
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作者 胡均平 李科军 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第7期2578-2585,共8页
To increase the efficiency and reliability of the thermodynamics analysis of the hydraulic system, the method based on pseudo-bond graph is introduced. According to the working mechanism of hydraulic components, they ... To increase the efficiency and reliability of the thermodynamics analysis of the hydraulic system, the method based on pseudo-bond graph is introduced. According to the working mechanism of hydraulic components, they can be separated into two categories: capacitive components and resistive components. Then, the thermal-hydraulic pseudo-bond graphs of capacitive C element and resistance R element were developed, based on the conservation of mass and energy. Subsequently, the connection rule for the pseudo-bond graph elements and the method to construct the complete thermal-hydraulic system model were proposed. On the basis of heat transfer analysis of a typical hydraulic circuit containing a piston pump, the lumped parameter mathematical model of the system was given. The good agreement between the simulation results and experimental data demonstrates the validity of the modeling method. 展开更多
关键词 thermodynamics hydraulic system pseudo-bond graph piston pump modeling temperature simulation
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Parallelized User Clicks Recognition from Massive HTTP Data Based on Dependency Graph Model 被引量:1
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作者 FANG Chcng LIU Jun LEI Zhenming 《China Communications》 SCIE CSCD 2014年第12期13-25,共13页
With increasingly complex website structure and continuously advancing web technologies,accurate user clicks recognition from massive HTTP data,which is critical for web usage mining,becomes more difficult.In this pap... With increasingly complex website structure and continuously advancing web technologies,accurate user clicks recognition from massive HTTP data,which is critical for web usage mining,becomes more difficult.In this paper,we propose a dependency graph model to describe the relationships between web requests.Based on this model,we design and implement a heuristic parallel algorithm to distinguish user clicks with the assistance of cloud computing technology.We evaluate the proposed algorithm with real massive data.The size of the dataset collected from a mobile core network is 228.7GB.It covers more than three million users.The experiment results demonstrate that the proposed algorithm can achieve higher accuracy than previous methods. 展开更多
关键词 cloud computing massive data graph model web usage mining
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The Refinement Algorithm Consideration in Text Clustering Scheme Based on Multilevel Graph
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作者 CHENJian-bin DONGXiang-jun SONGHan-tao 《Wuhan University Journal of Natural Sciences》 EI CAS 2004年第5期671-675,共5页
To construct a high efficient text clustering algorithm the multilevel graph model and the refinement algorithm used in the uncoarsening phase is discussed. The model is applied to text clustering. The performance of ... To construct a high efficient text clustering algorithm the multilevel graph model and the refinement algorithm used in the uncoarsening phase is discussed. The model is applied to text clustering. The performance of clustering algorithm has to be improved with the refinement algorithm application. The experiment result demonstrated that the multilevel graph text clustering algorithm is available. Key words text clustering - multilevel coarsen graph model - refinement algorithm - high-dimensional clustering CLC number TP301 Foundation item: Supported by the National Natural Science Foundation of China (60173051)Biography: CHEN Jian-bin(1970-), male, Associate professor, Ph. D., research direction: data mining. 展开更多
关键词 text clustering multilevel coarsen graph model refinement algorithm high-dimensional clustering
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Document Clustering Using Graph Based Fuzzy Association Rule Generation
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作者 P.Perumal 《Computer Systems Science & Engineering》 SCIE EI 2022年第10期203-218,共16页
With the wider growth of web-based documents,the necessity of automatic document clustering and text summarization is increased.Here,document summarization that is extracting the essential task with appropriate inform... With the wider growth of web-based documents,the necessity of automatic document clustering and text summarization is increased.Here,document summarization that is extracting the essential task with appropriate information,removal of unnecessary data and providing the data in a cohesive and coherent manner is determined to be a most confronting task.In this research,a novel intelligent model for document clustering is designed with graph model and Fuzzy based association rule generation(gFAR).Initially,the graph model is used to map the relationship among the data(multi-source)followed by the establishment of document clustering with the generation of association rule using the fuzzy concept.This method shows benefit in redundancy elimination by mapping the relevant document using graph model and reduces the time consumption and improves the accuracy using the association rule generation with fuzzy.This framework is provided in an interpretable way for document clustering.It iteratively reduces the error rate during relationship mapping among the data(clusters)with the assistance of weighted document content.Also,this model represents the significance of data features with class discrimination.It is also helpful in measuring the significance of the features during the data clustering process.The simulation is done with MATLAB 2016b environment and evaluated with the empirical standards like Relative Risk Patterns(RRP),ROUGE score,and Discrimination Information Measure(DMI)respectively.Here,DailyMail and DUC 2004 dataset is used to extract the empirical results.The proposed gFAR model gives better trade-off while compared with various prevailing approaches. 展开更多
关键词 Document clustering text summarization fuzzy model association rule generation graph model relevance mapping feature patterns
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Markov Graph Model Computation and Its Application to Intrusion Detection
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作者 曾剑平 郭东辉 《Journal of Donghua University(English Edition)》 EI CAS 2007年第2期272-275,共4页
Markov model is usually selected as the base model of user action in the intrusion detection system (IDS). However, the performance of the IDS depends on the status space of Markov model and it will degrade as the spa... Markov model is usually selected as the base model of user action in the intrusion detection system (IDS). However, the performance of the IDS depends on the status space of Markov model and it will degrade as the space dimension grows. Here, Markov Graph Model (MGM) is proposed to handle this issue. Specification of the model is described, and several methods for probability computation with MGM are also presented. Based on MGM, algorithms for building user model and predicting user action are presented. And the performance of these algorithms such as computing complexity, prediction accuracy, and storage requirement of MGM are analyzed. 展开更多
关键词 Markov graph Model intrusion detection probability computation
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Graph-based Lexicalized Reordering Models for Statistical Machine Translation
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作者 SU Jinsong LIU Yang +1 位作者 LIU Qun DONG Huailin 《China Communications》 SCIE CSCD 2014年第5期71-82,共12页
Lexicalized reordering models are very important components of phrasebased translation systems.By examining the reordering relationships between adjacent phrases,conventional methods learn these models from the word a... Lexicalized reordering models are very important components of phrasebased translation systems.By examining the reordering relationships between adjacent phrases,conventional methods learn these models from the word aligned bilingual corpus,while ignoring the effect of the number of adjacent bilingual phrases.In this paper,we propose a method to take the number of adjacent phrases into account for better estimation of reordering models.Instead of just checking whether there is one phrase adjacent to a given phrase,our method firstly uses a compact structure named reordering graph to represent all phrase segmentations of a parallel sentence,then the effect of the adjacent phrase number can be quantified in a forward-backward fashion,and finally incorporated into the estimation of reordering models.Experimental results on the NIST Chinese-English and WMT French-Spanish data sets show that our approach significantly outperforms the baseline method. 展开更多
关键词 natural language processing statistical machine translation lexicalized reordering model reordering graph
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STPGTN-AMulti-Branch Parameters Identification Method Considering Spatial Constraints and Transient Measurement Data
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作者 Shuai Zhang Liguo Weng 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第9期2635-2654,共20页
Transmission line(TL)Parameter Identification(PI)method plays an essential role in the transmission system.The existing PI methods usually have two limitations:(1)These methods only model for single TL,and can not con... Transmission line(TL)Parameter Identification(PI)method plays an essential role in the transmission system.The existing PI methods usually have two limitations:(1)These methods only model for single TL,and can not consider the topology connection of multiple branches for simultaneous identification.(2)Transient bad data is ignored by methods,and the random selection of terminal section data may cause the distortion of PI and have serious consequences.Therefore,a multi-task PI model considering multiple TLs’spatial constraints and massive electrical section data is proposed in this paper.The Graph Attention Network module is used to draw a single TL into a node and calculate its influence coefficient in the transmission network.Multi-Task strategy of Hard Parameter Sharing is used to identify the conductance ofmultiple branches simultaneously.Experiments show that themethod has good accuracy and robustness.Due to the consideration of spatial constraints,the method can also obtain more accurate conductance values under different training and testing conditions. 展开更多
关键词 Transmission lines parameter identification graph modeling method deep learning
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Entity generation algorithm based on reference expansion
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作者 Jia-Jia Ruan Xi-Xu He +1 位作者 Min Zhang Yuan Gao 《Journal of Electronic Science and Technology》 EI CAS CSCD 2023年第3期63-72,共10页
The extraction and understanding of text knowledge become increasingly crucial in the age of big data.One of the current research areas in the field of natural language processing(NLP)is how to accurately understand t... The extraction and understanding of text knowledge become increasingly crucial in the age of big data.One of the current research areas in the field of natural language processing(NLP)is how to accurately understand the text and collect accurate linguistic information because Chinese vocabulary is diverse and ambiguous.This paper mainly studies the candidate entity generation module of the entity link system.The candidate entity generation module constructs an entity reference expansion algorithm to improve the recall rate of candidate entities.In order to improve the efficiency of the connection algorithm of the entire system while ensuring the recall rate of candidate entities,we design a graph model filtering algorithm that fuses shallow semantic information to filter the list of candidate entities,and verify and analyze the efficiency of the algorithm through experiments.By analyzing the related technology of the entity linking algorithm,we study the related technology of candidate entity generation and entity disambiguation,improve the traditional entity linking algorithm,and give an innovative and practical entity linking model.The recall rate exceeds 82%,and the link accuracy rate exceeds 73%.Efficient and accurate entity linking can help machines to better understand text semantics,further promoting the development of NLP and improving the users’knowledge acquisition experience on the text. 展开更多
关键词 Chinese Wikipedia Entity reference expansion graph model
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Local Trade Networks among Farmers and Traders
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作者 Abdul-Samad Abdul-Rahaman Patience Pokuaa Gambrah 《Social Networking》 2023年第4期93-110,共18页
Both farmers and traders benefit from trade networking, which is crucial for the local economy. Therefore, it is crucial to understand how these networks operate, and how they can be managed more effectively. Througho... Both farmers and traders benefit from trade networking, which is crucial for the local economy. Therefore, it is crucial to understand how these networks operate, and how they can be managed more effectively. Throughout this study, we examine the economic networks formed between farmers and traders through the trade of food products. These networks are analyzed from the perspective of their structure and the factors that influence their development. Using data from 18 farmers and 15 traders, we applied exponential random graph models. The results of our study showed that connectivity, Popularity Spread, activity spread, good transportation systems, and high yields all affected the development of networks. Therefore, farmers’ productivity and high market demand can contribute to local food-crop trade. The network was not affected by reciprocity, open markets, proximity to locations, or trade experience of actors. Policy makers should consider these five factors when formulating policies for local food-crop trade. Additionally, local actors should be encouraged to use these factors to improve their network development. However, it is important to note that these factors alone cannot guarantee success. Policy makers and actors must also consider other factors such as legal frameworks, economic policies, and resource availability. Our approach can be used in future research to determine how traders and farmers can enhance productivity and profit in West Africa. This study addresses a research gap by examining factors influencing local food trade in a developing country. 展开更多
关键词 Local Trade Social Network Analysis Food Trade Exponential Random graph Models (ERGM) Food Security
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Stability analysis of reef fish communities based on symbiotic graph model
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作者 Danfeng Zhao Yaru Lou +2 位作者 Wei Song Dongmei Huang Xiaoliang Wang 《Aquaculture and Fisheries》 CSCD 2024年第6期1007-1017,共11页
The community stability of coral reefs and fish is the focus of ecological monitoring of coral reefs.Among them,the realization of effective metrics of variations in reef fish communities(i.e.,the combined communities... The community stability of coral reefs and fish is the focus of ecological monitoring of coral reefs.Among them,the realization of effective metrics of variations in reef fish communities(i.e.,the combined communities of coral reefs and fish)is important for analyzing the stability of communities as well as maintaining the ecological balance of coral reefs.Based on coral reef and fish data collected at St.John’s Island from 2004 to 2010,this study proposes a symbiotic graph modeling method to express the biological relationships of reef fish communities,and a Pyramid Match graph kernel method for fusing Attributes(PMA)to quantify community fluctuations to measure interannual variability of communities.The results showed that the community similarity was low in 2006,2007,and 2008.The total coral cover rate in the study area decreased by 32.04% from 2006 to 2007 and increased by 24% in 2008.The total number of fish fell from 3780 in 2006 to 2596 in 2007 and rose to 6249 in 2008.Among them,the proportion of herbivorous fish decreased to 30.84% in 2007.Furthermore,we have combined the Louvain algorithm with the proposed PMA method to effectively identify the regions that should be prioritized for protection.Experiments were conducted on real datasets with good results,demonstrating the potential of the proposed method to assist in the analysis of community stability and identification of priority conservation areas. 展开更多
关键词 Reef fish community Community stability Community variation Symbiotic graph model graph kernel Conservation area
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Multi-satellite observation integrated scheduling method oriented to emergency tasks and common tasks 被引量:23
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作者 Guohua Wu Manhao Ma +1 位作者 Jianghan Zhu Dishan Qiu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2012年第5期723-733,共11页
Satellite observation scheduling plays a significant role in improving the efficiency of satellite observation systems.Although many scheduling algorithms have been proposed,emergency tasks,characterized as importance... Satellite observation scheduling plays a significant role in improving the efficiency of satellite observation systems.Although many scheduling algorithms have been proposed,emergency tasks,characterized as importance and urgency(e.g.,observation tasks orienting to the earthquake area and military conflict area),have not been taken into account yet.Therefore,it is crucial to investigate the satellite integrated scheduling methods,which focus on meeting the requirements of emergency tasks while maximizing the profit of common tasks.Firstly,a pretreatment approach is proposed,which eliminates conflicts among emergency tasks and allocates all tasks with a potential time-window to related orbits of satellites.Secondly,a mathematical model and an acyclic directed graph model are constructed.Thirdly,a hybrid ant colony optimization method mixed with iteration local search(ACO-ILS) is established to solve the problem.Moreover,to guarantee all solutions satisfying the emergency task requirement constraints,a constraint repair method is presented.Extensive experimental simulations show that the proposed integrated scheduling method is superior to two-phased scheduling methods,the performance of ACO-ILS is greatly improved in both evolution speed and solution quality by iteration local search,and ACO-ILS outperforms both genetic algorithm and simulated annealing algorithm. 展开更多
关键词 satellite scheduling emergency task ant colony optimization(ACO) iteration local search(ILS) acyclic directed graph model
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Attitude Analysis in Process Conflict for C919 Aircraft Manufacturing 被引量:4
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作者 Xu Haiyan Xu Peng Sharafat Ali 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2017年第2期115-124,共10页
Based on the option prioritization in graph model for conflict resolution of two decision makers(DMs),new logical and matrix representations of four stability concepts for DMs′attitude are proposed.The logical repres... Based on the option prioritization in graph model for conflict resolution of two decision makers(DMs),new logical and matrix representations of four stability concepts for DMs′attitude are proposed.The logical representation of attitude is defined,and converted to the matrix form in order to develop a decision support system(DSS)efficiently.Compared with existing definitions of DMs′attitude based on states,the proposed definitions of attitude based on options are convenient and more effective to generate preferences since that of states can be significantly larger than that of options in a large conflict.In addition,it is easier to obtain the information of the prioritization of option statements than to obtain preference of states for users.The proposed representations are applied to the process conflict during aircraft manufacturing to demonstrate the efficiency of the new approach. 展开更多
关键词 graph model for conflict resolution ATTITUDES option prioritization process conflict for aircraft manufacturing
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A Novel Unsupervised Change Detection Method with Structure Consistency and GFLICM Based on UAV Images 被引量:3
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作者 Wensong LIU Xinyuan JI +2 位作者 Jie LIU Fengcheng GUO Zongqiao YU 《Journal of Geodesy and Geoinformation Science》 2022年第1期91-102,共12页
With the rapid development of Unmanned Aerial Vehicle(UAV)technology,change detection methods based on UAV images have been extensively studied.However,the imaging of UAV sensors is susceptible to environmental interf... With the rapid development of Unmanned Aerial Vehicle(UAV)technology,change detection methods based on UAV images have been extensively studied.However,the imaging of UAV sensors is susceptible to environmental interference,which leads to great differences of same object between UAV images.Overcoming the discrepancy difference between UAV images is crucial to improving the accuracy of change detection.To address this issue,a novel unsupervised change detection method based on structural consistency and the Generalized Fuzzy Local Information C-means Clustering Model(GFLICM)was proposed in this study.Within this method,the establishment of a graph-based structural consistency measure allowed for the detection of change information by comparing structure similarity between UAV images.The local variation coefficient was introduced and a new fuzzy factor was reconstructed,after which the GFLICM algorithm was used to analyze difference images.Finally,change detection results were analyzed qualitatively and quantitatively.To measure the feasibility and robustness of the proposed method,experiments were conducted using two data sets from the cities of Yangzhou and Nanjing.The experimental results show that the proposed method can improve the overall accuracy of change detection and reduce the false alarm rate when compared with other state-of-the-art change detection methods. 展开更多
关键词 change detection UAV images graph model structural consistency Generalized Fuzzy Local Information C-means Clustering Model(GFLICM)
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A version management model of PDM system and its realization 被引量:2
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作者 钟诗胜 李涛 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2008年第4期459-464,共6页
Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic grap... Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic graph is used to describe a version model. Three storage modes of the directed acyelic graph version model in the database, the bumping block and the PDM working memory are presented and the conversion principle of these three modes is given. The study indicates that building a dynamic product structure configuration model based on versions is the key to resolve the problem. Thus a version model of single product object is built. Then the version management model in product structure configuration is built and the application of version management of PDM syster is presented as a case. 展开更多
关键词 product data management (PDM) version management directed acyclic graph version model product structure configuration management
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Dynamic airspace sectorization via improved genetic algorithm 被引量:6
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作者 Yangzhou Chen Hong Bi +1 位作者 Defu Zhang Zhuoxi Song 《Journal of Modern Transportation》 2013年第2期117-124,共8页
This paper deals with dynamic airspace sectorization (DAS) problem by an improved genetic algorithm (iGA). A graph model is first constructed that represents the airspace static structure. Then the DAS problem is ... This paper deals with dynamic airspace sectorization (DAS) problem by an improved genetic algorithm (iGA). A graph model is first constructed that represents the airspace static structure. Then the DAS problem is formulated as a graph-partitioning problem to balance the sector workload under the premise of ensuring safety. In the iGA, multiple populations and hybrid coding are applied to determine the optimal sector number and airspace sectorization. The sector constraints are well satisfied by the improved genetic operators and protect zones. This method is validated by being applied to the airspace of North China in terms of three indexes, which are sector balancing index, coordination workload index and sector average flight time index. The improvement is obvious, as the sector balancing index is reduced by 16.5 %, the coordination workload index is reduced by 11.2 %, and the sector average flight time index is increased by 11.4 % during the peak-hour traffic. 展开更多
关键词 Dynamic airspace sectorization (DAS) Improved genetic algorithm (iGA) graph model Multiple populations Hybrid coding Sector constraints
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Structural Indexing for 3D Solid Digital Library 被引量:1
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作者 Han Shui\|hua, Lu Zheng\|ding, Chen Chuan\|bo Department of Computer Engineering, Huazhong University of Science and Teclonogy, Wuhan 430074,Chian 《Wuhan University Journal of Natural Sciences》 CAS 2001年第Z1期438-442,共5页
In a very large digital library that support computer aided collaborative design, an indexing process is crucial whenever the retrieval process has to select among many possible designs. In this paper, we address the... In a very large digital library that support computer aided collaborative design, an indexing process is crucial whenever the retrieval process has to select among many possible designs. In this paper, we address the problem of retrieving important design and engineering information by structural indexing. A design is represented by a model dependency graph, therefor, the indexing problem is to determine whether a graph is present or absent in a database of model dependency graphs. we present a novel graph indexing method using polynomial characterization of a model dependency graph and on hashing. Such an approach is able to create an high efficient 3D solid digital library for retrieving and extracting solid geometric model and engineering information. 展开更多
关键词 digital library computer aided design model dependency graphs HASHING INDEXING
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