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Artificial Intelligence and Robotics

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Articles 3301 - 3330 of 4370

Full-Text Articles in Computer Engineering

Multi-Evidence Learning For Medical Diagnosis, Tongjai Yampaka Jan 2020

Multi-Evidence Learning For Medical Diagnosis, Tongjai Yampaka

Chulalongkorn University Theses and Dissertations (Chula ETD)

In recent years, a great many approaches for learning from multiple sources by considering the diversity of different views have been proposed. The most interesting field is medical diagnosis. For example, breast cancer screening normally employs two views of mammography (Cranio-Caudal and Medio-Lateral-Oblique) or two modes of ultrasound (B-mode and Doppler mode) breast images. This study proposes a multi-evidence learning model that combines the multiple evidences of breast images to improve diagnosis. Two views mammography and two modes of ultrasound were used. Our proposed model consists of four stages. First, feature extraction using Convolutional Neuron Networks was operated to extract …

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A Robust System For Core Thai Natural Language Processing Technologies, Can Udomcharoenchaikit Jan 2020

A Robust System For Core Thai Natural Language Processing Technologies, Can Udomcharoenchaikit

Chulalongkorn University Theses and Dissertations (Chula ETD)

As the amount of unstructured textual data grows, it becomes increasingly important to build an intelligent system that can process it. Natural Language Processing (NLP) is a technology that allows a computer to exploit human languages to perform tasks. Deep learning models have shown excellent results across fundamental tasks in NLP, such as word segmentation, part-of-speech tagging, and named-entity recognition. However, in many situations, these proposed methods fail to perform well. For an NLP system to be robust, it must address issues such as out-of-vocabulary and spelling-mistakes. This thesis's research goal is to develop NLP models that can handle malformed …

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Semi-Supervised Thai Sentence Segmentation Using Local And Distant Word Representations, Chanatip Saetia Jan 2020

Semi-Supervised Thai Sentence Segmentation Using Local And Distant Word Representations, Chanatip Saetia

Chulalongkorn University Theses and Dissertations (Chula ETD)

A sentence is typically treated as the minimal syntactic unit used for extracting valuable information from a longer piece of text. However, in written Thai, there are no explicit sentence markers. We proposed a deep learning model for the task of sentence segmentation that includes three main contributions. First, we integrate n-gram embedding as a local representation to capture word groups near sentence boundaries. Second, to focus on the keywords of dependent clauses, we combine the model with a distant representation obtained from self-attention modules. Finally, due to the scarcity of labeled data, for which annotation is difficult and time-consuming, …

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Deep Sequential Real Estate Recommendation Approach For Solving Item Cold Start Problem, Jirut Polohakul Jan 2020

Deep Sequential Real Estate Recommendation Approach For Solving Item Cold Start Problem, Jirut Polohakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

The item cold-start problem occurs when a recommendation system cannot recommend new items owing to record deficiencies and new listing omissions. When searching for real estate, users can register a concurrent interest in recent and prior projects. Thus, an approach to recommend cold-start and warm-start items simultaneously must be determined. Furthermore, unrequired membership and stop-by behavior cause real estate recommendations to have many cold-start and new users. This characteristic encourages the use of a content-based approach and a session-based recommendation system. Herein, we propose a real estate recommendation approach for solving the item cold-start problem with acceptable warm-start item recommendations …

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A Real Estate Valuation Model Using Boosted Feature Selection, Kankawee Chanasit Jan 2020

A Real Estate Valuation Model Using Boosted Feature Selection, Kankawee Chanasit

Chulalongkorn University Theses and Dissertations (Chula ETD)

To estimate real estate values, a complex valuation model based on artificial neural network (ANN) has been established as a successful means in modern machine learning research, specifically when high-dimensional data are available. Unfortunately, the real estate data in many locations, such as Thailand, are quite limited in terms of features. Hence, it becomes mandatory to reduce the complexity using feature selection techniques. These techniques aim to improve performance by identifying significant factors and help decrease the computational overload and model construction. However, due to the lack of explicability and interpretability in ANNs, the analysis of input factors cannot be …

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Detection Of Wagyu Beef Sources With Image Classification Using Convolutional Neural Network, Nattakorn Kointarangkul Jan 2020

Detection Of Wagyu Beef Sources With Image Classification Using Convolutional Neural Network, Nattakorn Kointarangkul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Wagyu beef originated in Japan. However, there are many types of Wagyu beef in the market around the globe. Primary sources include Australia, USA, Canada and the United Kingdom. The authentic Japanese Wagyu is well known for its intense marbling, juicy rich flavor and tenderness. Observing that there are differences in flavor, texture, and quality between distinct sources of Wagyu. This research presents an AI-based approach to identify Wagyu beef sources with image classification. The input images were collected from reliable sources on the internet and augmented with DCGAN. Deep neural networks, CNN, was constructed to detect the marbled fat …

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Using Automatic Speech Recognition To Assess Thai Speech Language Fluency In Montreal Cognitive Assessment (Moca), Pimarn Kantithammakorn Jan 2020

Using Automatic Speech Recognition To Assess Thai Speech Language Fluency In Montreal Cognitive Assessment (Moca), Pimarn Kantithammakorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

The Montreal Cognitive Assessment (MoCA), a widely accepted screening tool for identifying patients with mild cognitive impairment (MCI), includes a language fluency test of verbal functioning where scores are based on the number of unique correct words produced by the test-taker. However, with different languages, it is possible that unique words may be counted differently. This study focuses on Thai as a language that differs from English in its type of word combination. We applied various automatic speech recognition (ASR) techniques to develop an assisted scoring system for the language fluency test of the MoCA with Thai language support. The …

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Accurate Surface Ultraviolet Radiation Forecasting For Clinical Applications With Deep Neural Network, Raksit Raksasat Jan 2020

Accurate Surface Ultraviolet Radiation Forecasting For Clinical Applications With Deep Neural Network, Raksit Raksasat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Exposure to appropriate doses of UV radiation provides enormously health and medical treatment benefits including psoriasis. Typical hospital-based phototherapy cabinets contain a bunch of artificial lamps, either broad-band (main emission spectrum 280-360 nm, maximum 320 nm), or narrow-band UV B irradiation (main emission spectrum 310-315nm, maximum 311nm). For patients who cannot access phototherapy centers, sun-bathing, or heliotherapy, can be a safe and effective treatment alternative. However, as sunlight contains the full range of UV radiation (290-400 nm), careful sun-bathing supervised by photodermatologist based on accurate UV radiation forecast is vital to minimize potential adverse effects. Here, using 10-year UV radiation …

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Generating Energy Data For Machine Learning With Recurrent Generative Adversarial Networks, Mohammad Navid Fekri, Ananda M. Ghosh, Katarina Grolinger Dec 2019

Generating Energy Data For Machine Learning With Recurrent Generative Adversarial Networks, Mohammad Navid Fekri, Ananda M. Ghosh, Katarina Grolinger

Electrical and Computer Engineering Publications

The smart grid employs computing and communication technologies to embed intelligence into the power grid and, consequently, make the grid more efficient. Machine learning (ML) has been applied for tasks that are important for smart grid operation including energy consumption and generation forecasting, anomaly detection, and state estimation. These ML solutions commonly require sufficient historical data; however, this data is often not readily available because of reasons such as data collection costs and concerns regarding security and privacy. This paper introduces a recurrent generative adversarial network (R-GAN) for generating realistic energy consumption data by learning from real data. Generativea adversarial …

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Design Of A Flexible System Simulation Evaluation Framework, Rusheng Ju, Zimin Cai, Wang Song, Wang Peng Dec 2019

Design Of A Flexible System Simulation Evaluation Framework, Rusheng Ju, Zimin Cai, Wang Song, Wang Peng

Journal of System Simulation

Abstract: To meet variable evaluation requirement of complex system simulation, this paper puts forward a design strategy of flexible effectiveness evaluation framework. The composition structure of system simulation evaluation framework is analyzed. To help users design reference dynamically, the method of evaluation reference edit and display is introduced based on Web. To enhance the extensibility of evaluation model, the method of interface design and code generation is investigated. To ensure the flexibility and extensibility of evaluation framework, the relation and mapping mechanism of evaluation references, evaluation model and evaluation result is studied. The framework is realized and verified in …

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Research On Simulation Platform For Equipment System Analysis, Yuping Li, Shaojie Mao, Zhenqi Ju, Zhou Fang, Guoqiang Yan Dec 2019

Research On Simulation Platform For Equipment System Analysis, Yuping Li, Shaojie Mao, Zhenqi Ju, Zhou Fang, Guoqiang Yan

Journal of System Simulation

Abstract: With the development of equipment construction from platform-centric to network-centric, simulation analysis of equipment system is an important means and tool to support the transformation and development of equipment construction under the condition of multi-task joint operation. Starting from the requirement of system simulation analysis, a cloud-based equipment system simulation architecture is proposed to realize flexible and configurable simulation environment according to task requirements; and a high-performance simulation framework is conducted, which provides strong support for different application modes, such as parallel hyper-real-time and distributed simulation deduction. The unified description, organization and management method of model and data resources …

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Research On Corridor Setting Based On Pedestrian Simulation Of Social Groups, Yiting Xu, Zhang Rui Dec 2019

Research On Corridor Setting Based On Pedestrian Simulation Of Social Groups, Yiting Xu, Zhang Rui

Journal of System Simulation

Abstract: As the connector of each space in the hub, the rail transit hub corridor plays the role of transition and buffer. The existence of social groups makes an important impact on pedestrian traffic and its simulation. The paper supplements the consideration of pedestrian traffic related studies on social groups travel, analyses the characteristics of social groups in rail transit hub corridor, improves Moussaïd social group force model, and redevelops AnyLogic micro-simulation platform based on Python language. Taking a subway station in Beijing as an example, fully considering the influence of social groups, it is obtained that the optimal channel …

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Parallel Tasks Optimization Scheduling In Cloud Manufacturing System, Chenwei Feng, Wang Yan Dec 2019

Parallel Tasks Optimization Scheduling In Cloud Manufacturing System, Chenwei Feng, Wang Yan

Journal of System Simulation

Abstract: To solve the problem of unbalanced resource requirements and low resource utilization when the same type of tasks are executed in parallel in the cloud manufacturing system, a task resource scheduling model with the goal of minimizing cost, minimizing time, maximizing reliability and optimizing quality is established. A non-dominated sorting genetic algorithm based on reference points (NSGA-III) is adopted to solve the model by combining real number matrix coding and crossover and mutation based on real number coding instead of common evolutionary strategy. And an optimal decision strategy based on combination of analytic hierarchy process and entropy value method …

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Research On The Value Accessing Method For Calibrating Micro Traffic Simulation Model Parameters, Chenjing Zhou, Rong Jian, Kwok Lam Dec 2019

Research On The Value Accessing Method For Calibrating Micro Traffic Simulation Model Parameters, Chenjing Zhou, Rong Jian, Kwok Lam

Journal of System Simulation

Abstract: Parameter calibration is the precondition of the application of micro traffic simulation technology. This study focuses on the value accessing method for parameter calibration in order to further improve the parameter calibration process. The analysis of the distribution characteristics of each parameter calibration results shows that the parameters have different trends in the process of gradual iteration, and there are multiple optimal solutions for the model parameter calibration results. In this paper, the dispersion is used as the quantitative analysis index of the concentration degree of each parameter calibration result, and the parameter value of the model is determined …

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Research On Source Seeking Methods Of Harmful Gas Leakage In Chemical Industry Parks, Zhao Yong, Bin Chen, Xiaodong Wang, Zhengqiu Zhu, Rongxiao Wang, Xiaogang Qiu Dec 2019

Research On Source Seeking Methods Of Harmful Gas Leakage In Chemical Industry Parks, Zhao Yong, Bin Chen, Xiaodong Wang, Zhengqiu Zhu, Rongxiao Wang, Xiaogang Qiu

Journal of System Simulation

Abstract: Chemical production safety accidents often lead to harmful gas leakage, causing serious environmental damage and casualties. Mastering the information of leaking source quickly can assist in emergency disposal decisions and reduce the harm of accidents. In this paper, Entrotaxis algorithm is used to guide the ground source seeking equipment to move to the vicinity of the leaking source quickly and autonomously in a chemical park scene, and to master the source information. According to the characteristics of the chemical industry park scene, this paper applies intermittent search module into Entrotaxis algorithm and proposes a robust and suitable algorithm (Entrotaxis-Jump …

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Numerical Simulation Analysis Of Anti-Blast Impact Of Underground Rescue Capsule Based On Ls-Dyna, Zhang Fan, Yuanhua Yang, Xiaoxu He, Deng Yu Dec 2019

Numerical Simulation Analysis Of Anti-Blast Impact Of Underground Rescue Capsule Based On Ls-Dyna, Zhang Fan, Yuanhua Yang, Xiaoxu He, Deng Yu

Journal of System Simulation

Abstract: Aiming at the strength problem of the underground rescue cabin under explosion impact load, a finite element model of overall explosion impact load and fluid-solid coupling structure response is established in transient dynamic soft LS-DYNA. The flow field impact load is generated by explosion algorithm, and the propagation of the impact load in the air is calculated. The dynamic response of the rescue cabin structure under the impact load is calculated by the fluid-solid coupling method. The results show that the maximum load occurs on the end surface closest to the explosion source, and the structural deformation is small …

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The Scheduling Algorithm Of Cloud Job Based On Hopfield Neural Network, Yudong Guo, Jinping Zuo Dec 2019

The Scheduling Algorithm Of Cloud Job Based On Hopfield Neural Network, Yudong Guo, Jinping Zuo

Journal of System Simulation

Abstract: Focusing on the low efficiency of cloud job scheduling and the insufficient utility of resource, a job scheduling algorithm based on Hopfield Neural Network is proposed. In order to improve the resource scheduling ability of the system, The resource characteristics which influence the cloud job scheduling are shown. The mathematical model of resource constraints is established, and the Hopfield energy function is designed and optimized. The average utilization rate of 9 nodes is analyzed by using the standard test cases, and the performance and resource utilization of the proposed strategy are compared with three typical algorithms. …

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Simulation Research On Attitude Solution Method Of Micro-Mini Missile, Chunbo Zhao, Junfang Fan, Liu Ning Dec 2019

Simulation Research On Attitude Solution Method Of Micro-Mini Missile, Chunbo Zhao, Junfang Fan, Liu Ning

Journal of System Simulation

Abstract: Aiming at the problem of attitude measurement error in the inertial navigation system of micro and small guided ammunition under eccentric structure, the attitude solution and error compensation optimization are studied by using rotation vector optimization of multiple sub-samples, such as monotone sample, two sub-samples, three sub-samples and four sub-samples, and the fourth-order runge kutta algorithm. Through error compensation and optimization of measured data, the results show that the monomorphic modified algorithm has the worst optimization effect, the fourth-order runge kutta optimization algorithm has the best effect, and the maximum drift error of attitude Angle is better than 10 …

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Multi-Objective Optimization Design Of Aerodynamic Layout For Twin Swept-Wing Aircraft, Yuchang Lei, Dengcheng Zhang, Yanhua Zhang, Guangxu Su, Luo Hao, Zhan Ren Dec 2019

Multi-Objective Optimization Design Of Aerodynamic Layout For Twin Swept-Wing Aircraft, Yuchang Lei, Dengcheng Zhang, Yanhua Zhang, Guangxu Su, Luo Hao, Zhan Ren

Journal of System Simulation

Abstract: Multi-objective optimization of aerodynamic layout is a key technology in the design of vehicles. The overall configuration of the shape parameters is optimized with a double swept-shaped wave shape as the basic configuration. We use NSGA-Ⅱ multi-objective genetic algorithm, take the aircraft double sweep angle as the design variable, consider the maximum takeoff weight, range, volume ratio and other performance indicators, use Elman neural network to establish the relationship between shape parameters and performance parameters, and establish constraints based on mission planning requirements. The Pareto optimal solution set is obtained by using optimized design and the individuals with …

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Fast Simulation Of Yacht In Calm Water Based On Improved Savitsky Method, Xiaochen Li, Yin Yong Dec 2019

Fast Simulation Of Yacht In Calm Water Based On Improved Savitsky Method, Xiaochen Li, Yin Yong

Journal of System Simulation

Abstract: An improved Savitsky method is proposed to increase the accuracy of mathematical model of yacht in fast simulation. Three degrees of freedom mathematical model is established to simulate the motion in displacement regime. warped hull forms of yachts are simplified into prismatic hull and improved Savitsky method is used to calculate resistance. The simulation is carried out in pre-planing regime and planing regime. The validity of the proposed method has been assessed by comparing results with previous experimental data, which shows good agreements. The improved method runs well and the result is accurate when it is added to the …

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Knowledge Representation Method Of Joint Operation Situation Based On Knowledge Graph, Baokui Wang, Wu Lin, Xiaofeng Hu, Xiaoyuan He Dec 2019

Knowledge Representation Method Of Joint Operation Situation Based On Knowledge Graph, Baokui Wang, Wu Lin, Xiaofeng Hu, Xiaoyuan He

Journal of System Simulation

Abstract: Lacking of common knowledge for understanding and judging complex situation of operation by machines is one of the difficulties in intelligent situation cognition. The knowledge representation methods based on knowledge graph are reviewed. The characteristics and difficulties of joint operation situation knowledge representation are analyzed. Moreover, the concept of scenario knowledge graph is presented, as well as the knowledge sources and basic content of scenario knowledge graph are described. This paper also points out that the joint knowledge representation method based on discrete symbols and continuous vectors in specific scenario is an effective way to express joint operation situation …

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Dynamic Collision Optimization Algorithm Based On Ray Detection, Li Xing, Yanfang Fu, Wang Liang, Chengtao Lu Dec 2019

Dynamic Collision Optimization Algorithm Based On Ray Detection, Li Xing, Yanfang Fu, Wang Liang, Chengtao Lu

Journal of System Simulation

Abstract: Aiming at the inaccurate collision detection problem in Unity 3D-based visual simulation systems, a dynamic collision optimization algorithm based on ray detection is designed and implemented. The 3D virtual scene is segmented by octree, which simplifies the detection range of obstacles during the operation of simulation systems. At the same time, based on ray detection, according to the quantization coefficient and distance of the threat degree of obstacles, an appropriate collision collider is dynamically added to the obstacles to complete collision detection. The results show that the algorithm not only improves the fluency of visual simulation systems but also …

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Study On Optimization Of Shore Bridge Operator Scheduling Considering The Influence Of Ambient Temperature, Yibin Wang, Haihong Yu, Danlan Xie Dec 2019

Study On Optimization Of Shore Bridge Operator Scheduling Considering The Influence Of Ambient Temperature, Yibin Wang, Haihong Yu, Danlan Xie

Journal of System Simulation

Abstract: The refinement of port management puts forward new requirements for its service capacity, and human factors are the key factors affecting the port service capacity. It is a new and feasible research direction to improve port operation efficiency by adjusting human factors. Based on the theoretical model of temperature affecting efficiency, this paper uses FlexSim system simulation software to analyze the change of employee's working efficiency with time, and studies the optimal scheduling strategy of shore bridge operators under different temperatures. Finally, it is concluded that when the ambient temperature is suitable for human body, the eight-hour scheduling …

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A Method Of Manifold Learning For Locality Preserving Projections Based On Geodesic, Lijun Xu, Jinghan Fang, Yiping Wang Dec 2019

A Method Of Manifold Learning For Locality Preserving Projections Based On Geodesic, Lijun Xu, Jinghan Fang, Yiping Wang

Journal of System Simulation

Abstract: In order to solve the problem of under-fitting state of LPP algorithm in practical application,in this paper, the mapping principle of Locality Preserving Projections (LPP) is discussed in detail. The relationship of LPP method between the under-fitting state on certain dataset and adjacency graph is analyzed. The LPP manifold learning method (ISOLPP) is proposed on the basis of geodesic. The experiment results show that the good embedded effect is achieved by implenmenting ISOLPP method on multiple test data sets. It significantly improves the adaptability of the algorithm by not only inheriting the advantages of LPP algorithm with explicit projection …

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Synergic Production Scheduling Method For Distributed Multi-Plants Based On Fusion Decision Tree, Wang Yan, Tianlun Jiang Dec 2019

Synergic Production Scheduling Method For Distributed Multi-Plants Based On Fusion Decision Tree, Wang Yan, Tianlun Jiang

Journal of System Simulation

Abstract: In the synergic production scheduling optimization problem of distributed multi-plants, it is necessary to consider the two stages of job allocation between factories and job scheduling in factories at the same time. This paper first establishes a distributed multi-plant scheduling model with total cost and advance/delay as the optimization objectives, and then proposes a nested optimization algorithm framework integrating ID3 decision tree with Gauss particle swarm optimization. In this framework, independent scheduling optimization within the factory is nested in the process of inter factory allocation optimization, and elite retention strategy is introduced to improve the algorithm optimization. In …

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Overview Of Cooperative Target Assignment, Ou Qiao, Xiaoyuan He, Jiuyang Tao Dec 2019

Overview Of Cooperative Target Assignment, Ou Qiao, Xiaoyuan He, Jiuyang Tao

Journal of System Simulation

Abstract: The concept and connotation of combat coordination are briefly analyzed. The historical origin of cooperative target allocation and its orientation in command and control process are expounded. The research status of collaborative target allocation in model building and algorithm solving is analyzed comprehensively, the shortcomings of current research is pointed out. It is proposed that for the next step we should pay more attention to large-scale collaborative target allocation under dynamic and confrontational conditions, and focus on the real-time, adaptability and iterative evolution mechanism of the algorithm.

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A Mesh Model Simplification Method Based On Visual Feature Preservation, Che Li, Dejun Tang, Shimin Li, Fengju Kang Dec 2019

A Mesh Model Simplification Method Based On Visual Feature Preservation, Che Li, Dejun Tang, Shimin Li, Fengju Kang

Journal of System Simulation

Abstract: Aiming at the problems of mesh visual feature loss and oversimplification in mesh simplification algorithm, a visual feature preservation based triangle mesh model simplification algorithm is proposed. The multi-viewpoint perception method is used to measure the visual perception error caused by the difference between the original and the simplified model in the two-dimensional view under the optimal viewpoint set. Based on QEM algorithm, a novel geometric error metric is built by introducing the triangle shape factor. The triangle collapse error function is defined by combining visual perception and geometric error to control the simplified depth of the model. Through …

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Research On Clock Synchronization Of Simulation System Based On Ethernet And Optical Fiber Network, Yulin Meng, Shen Tao, Shuaihao Wang, Lüyi Zhao, Chengshi Tang Dec 2019

Research On Clock Synchronization Of Simulation System Based On Ethernet And Optical Fiber Network, Yulin Meng, Shen Tao, Shuaihao Wang, Lüyi Zhao, Chengshi Tang

Journal of System Simulation

Abstract: With the development of simulation communication and Ethernet clock synchronization technology, the traditional timing simulation method based on real-time operating system can not meet the accuracy requirements of clock synchronization between multi-simulation systems. A time synchronization method between simulation systems based on IEEE1588 clock synchronization protocol and optical fiber reflection memory network is proposed, in which the Beidou/GPS timing device periodically calibrates the real-time operating system, and the real-time operating system divides the frequency of the calibrated clock information and synchronizes the clock of each simulation system through the high-speed optical fiber reflection memory network. The clock synchronization …

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Research On Control Technology Of Aeroengine Heat Exchanger, Qingyang Jiang, Song Hua Dec 2019

Research On Control Technology Of Aeroengine Heat Exchanger, Qingyang Jiang, Song Hua

Journal of System Simulation

Abstract: In order to solve the high temperature problem caused by the high speed of the synergistic aspirating engine, this paper designs a control algorithm for the heat exchanger. In the process of designing the control algorithm, considering the strong nonlinearity, uncertainty and strong coupling of the engine, The decoupling study of the multi-input and multi-output linear model of the heat exchanger is carried out. The decoupling effect of two different decoupling methods on the strongly coupled heat exchanger is obtained. The fuzzy decoupling PID controller has short adjustment time and overshoot. Small, conclusions with better decoupling effects.

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Downhole Drilling Processing Data Acquisition And Stick Slip Characteristic Analysis, Huang Sheng, Zhang Tao, Chongjun Huang, Yumei Li, Deng Hu, Zhang Xia Dec 2019

Downhole Drilling Processing Data Acquisition And Stick Slip Characteristic Analysis, Huang Sheng, Zhang Tao, Chongjun Huang, Yumei Li, Deng Hu, Zhang Xia

Journal of System Simulation

Abstract: During oil drilling process, drill string vibrations are detrimental to the bit and drill string, which even causes failure of equipment. Researches show that, studying the law of near bit vibration data can reduce non-production time (NPT) and improve drilling efficiency. This paper uses power spectral density and wavelet transform to analyze vibration signals, then compares with normal drilling situation to find out stick slip characteristics. The results show that, when stick slip occurs, the mean value of lateral vibration fluctuates greatly, which indicates stick slip is mainly based on torsional vibration. From the perspective of power spectral density …

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