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Articles 22831 - 22860 of 63327

Full-Text Articles in Computer Sciences

Visual Commonsense R-Cnn, Tan Wang, Jianqiang Huang, Hanwang Zhang, Qianru Sun Jun 2020

Visual Commonsense R-Cnn, Tan Wang, Jianqiang Huang, Hanwang Zhang, Qianru Sun

Research Collection School Of Computing and Information Systems

We present a novel unsupervised feature representation learning method, Visual Commonsense Region-based Convolutional Neural Network (VC R-CNN), to serve as an improved visual region encoder for high-level tasks such as captioning and VQA. Given a set of detected object regions in an image (e.g., using Faster R-CNN), like any other unsupervised feature learning methods (e.g., word2vec), the proxy training objective of VC R-CNN is to predict the contextual objects of a region. However, they are fundamentally different: the prediction of VC R-CNN is by using causal intervention: P(Y|do(X)), while others are by using the conventional likelihood: P(Y|X). This is also …

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Is Using Deep Learning Frameworks Free?: Characterizing Technical Debt In Deep Learning Frameworks, Jiakun Liu, Qiao Huang, Xin Xia, Emad Shihab, David Lo, Shanping Li Jun 2020

Is Using Deep Learning Frameworks Free?: Characterizing Technical Debt In Deep Learning Frameworks, Jiakun Liu, Qiao Huang, Xin Xia, Emad Shihab, David Lo, Shanping Li

Research Collection School Of Computing and Information Systems

Developers of deep learning applications (shortened as application developers) commonly use deep learning frameworks in their projects. However, due to time pressure, market competition, and cost reduction, developers of deep learning frameworks (shortened as framework developers) often have to sacrifice software quality to satisfy a shorter completion time. This practice leads to technical debt in deep learning frameworks, which results in the increasing burden to both the application developers and the framework developers in future development.In this paper, we analyze the comments indicating technical debt (self-admitted technical debt) in 7 of the most popular open-source deep learning frameworks. Although framework …

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Understanding Android Voip Security: A System-Level Vulnerability Assessment, En He, Daoyuan Wu, Robert H. Deng Jun 2020

Understanding Android Voip Security: A System-Level Vulnerability Assessment, En He, Daoyuan Wu, Robert H. Deng

Research Collection School Of Computing and Information Systems

VoIP is a class of new technologies that deliver voice calls over the packet-switched networks, which surpasses the legacy circuit-switched telecom telephony. Android provides the native support of VoIP, including the recent VoLTE and VoWiFi standards. While prior works have analyzed the weaknesses of VoIP network infrastructure and the privacy concerns of third-party VoIP apps, no efforts were attempted to investigate the (in)security of Android’s VoIP integration at the system level. In this paper, we first demystify Android VoIP’s protocol stack and all its four attack surfaces. We then propose a novel vulnerability assessment approach that assembles on-device Intent/API fuzzing, …

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Revisiting Supervised And Unsupervised Methods For Effort-Aware Cross-Project Defect Prediction, Chao Ni, Xin Xia, David Lo, Xiang Chen, Qing Gu Jun 2020

Revisiting Supervised And Unsupervised Methods For Effort-Aware Cross-Project Defect Prediction, Chao Ni, Xin Xia, David Lo, Xiang Chen, Qing Gu

Research Collection School Of Computing and Information Systems

Cross-project defect prediction (CPDP), aiming to apply defect prediction models built on source projects to a target project, has been an active research topic. A variety of supervised CPDP methods and some simple unsupervised CPDP methods have been proposed. In a recent study, Zhou et al. found that simple unsupervised CPDP methods (i.e., ManualDown and ManualUp) have a prediction performance comparable or even superior to complex supervised CPDP methods. Therefore, they suggested that the ManualDown should be treated as the baseline when considering non-effort-aware performance measures (NPMs) and the ManualUp should be treated as the baseline when considering effort-aware performance …

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Gpu-Accelerated Subgraph Enumeration On Partitioned Graphs, Wentian Guo, Yuchen Li, Mo Sha, Bingsheng He, Xiaokui Xiao, Kian-Lee Tan Jun 2020

Gpu-Accelerated Subgraph Enumeration On Partitioned Graphs, Wentian Guo, Yuchen Li, Mo Sha, Bingsheng He, Xiaokui Xiao, Kian-Lee Tan

Research Collection School Of Computing and Information Systems

Subgraph enumeration is important for many applications such as network motif discovery and community detection. Recent works utilize graphics processing units (GPUs) to parallelize subgraph enumeration, but they can only handle graphs that fit into the GPU memory. In this paper, we propose a new approach for GPU-accelerated subgraph enumeration that can efficiently scale to large graphs beyond the GPU memory. Our approach divides the graph into partitions, each of which fits into the GPU memory. The GPU processes one partition at a time and searches the matched subgraphs of a given pattern (i.e., instances) within the partition as in …

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Provably Robust Decisions Based On Potentially Malicious Sources Of Information, Tim Muller, Dongxia Wang, Jun Sun Jun 2020

Provably Robust Decisions Based On Potentially Malicious Sources Of Information, Tim Muller, Dongxia Wang, Jun Sun

Research Collection School Of Computing and Information Systems

Sometimes a security-critical decision must be made using information provided by peers. Think of routing messages, user reports, sensor data, navigational information, blockchain updates. Attackers manifest as peers that strategically report fake information. Trust models use the provided information, and attempt to suggest the correct decision. A model that appears accurate by empirical evaluation of attacks may still be susceptible to manipulation. For a security-critical decision, it is important to take the entire attack space into account. Therefore, we define the property of robustness: the probability of deciding correctly, regardless of what information attackers provide. We introduce the notion of …

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Ntire 2020 Challenge On Video Quality Mapping: Methods And Results, D. Fuoli, Zhiwu Huang, M. Danelljan, R. Timofte, H. Wang, L. Jin, D. Su, J. Liu, J. Lee, M. Kudelski, L. Bala, D. Hryboy, M. Mozejko, M. Li, S. Li, B. Pang, C. Lu, Li C., He D., Li F. Jun 2020

Ntire 2020 Challenge On Video Quality Mapping: Methods And Results, D. Fuoli, Zhiwu Huang, M. Danelljan, R. Timofte, H. Wang, L. Jin, D. Su, J. Liu, J. Lee, M. Kudelski, L. Bala, D. Hryboy, M. Mozejko, M. Li, S. Li, B. Pang, C. Lu, Li C., He D., Li F.

Research Collection School Of Computing and Information Systems

This paper reviews the NTIRE 2020 challenge on video quality mapping (VQM), which addresses the issues of quality mapping from source video domain to target video domain. The challenge includes both a supervised track (track 1) and a weakly-supervised track (track 2) for two benchmark datasets. In particular, track 1 offers a new Internet video benchmark, requiring algorithms to learn the map from more compressed videos to less compressed videos in a supervised training manner. In track 2, algorithms are required to learn the quality mapping from one device to another when their quality varies substantially and weaklyaligned video pairs …

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Hyperbolic Visual Embedding Learning For Zero-Shot Recognition, Shaoteng Liu, Jingjing Chen, Liangming Pan, Chong-Wah Ngo, Tat-Seng Chua, Yu-Gang Jiang Jun 2020

Hyperbolic Visual Embedding Learning For Zero-Shot Recognition, Shaoteng Liu, Jingjing Chen, Liangming Pan, Chong-Wah Ngo, Tat-Seng Chua, Yu-Gang Jiang

Research Collection School Of Computing and Information Systems

This paper proposes a Hyperbolic Visual Embedding Learning Network for zero-shot recognition. The network learns image embeddings in hyperbolic space, which is capable of preserving the hierarchical structure of semantic classes in low dimensions. Comparing with existing zeroshot learning approaches, the network is more robust because the embedding feature in hyperbolic space better represents class hierarchy and thereby avoid misleading resulted from unrelated siblings. Our network outperforms exiting baselines under hierarchical evaluation with an extremely challenging setting, i.e., learning only from 1,000 categories to recognize 20,841 unseen categories. While under flat evaluation, it has competitive performance as state-of-the-art methods but …

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Transferring And Regularizing Prediction For Semantic Segmentation, Yiheng Zhang, Zhaofan Qiu, Ting Yao, Chong-Wah Ngo, Dong Liu, Tao Mei Jun 2020

Transferring And Regularizing Prediction For Semantic Segmentation, Yiheng Zhang, Zhaofan Qiu, Ting Yao, Chong-Wah Ngo, Dong Liu, Tao Mei

Research Collection School Of Computing and Information Systems

Semantic segmentation often requires a large set of images with pixel-level annotations. In the view of extremely expensive expert labeling, recent research has shown that the models trained on photo-realistic synthetic data (e.g., computer games) with computer-generated annotations can be adapted to real images. Despite this progress, without constraining the prediction on real images, the models will easily overfit on synthetic data due to severe domain mismatch. In this paper, we novelly exploit the intrinsic properties of semantic segmentation to alleviate such problem for model transfer. Specifically, we present a Regularizer of Prediction Transfer (RPT) that imposes the intrinsic properties …

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Exploring Category-Agnostic Clusters For Open-Set Domain Adaptation, Yingwei Pan, Ting Yao, Yehao Li, Chong-Wah Ngo, Tao Mei Jun 2020

Exploring Category-Agnostic Clusters For Open-Set Domain Adaptation, Yingwei Pan, Ting Yao, Yehao Li, Chong-Wah Ngo, Tao Mei

Research Collection School Of Computing and Information Systems

Unsupervised domain adaptation has received significant attention in recent years. Most of existing works tackle the closed-set scenario, assuming that the source and target domains share the exactly same categories. In practice, nevertheless, a target domain often contains samples of classes unseen in source domain (i.e., unknown class). The extension of domain adaptation from closedset to such open-set situation is not trivial since the target samples in unknown class are not expected to align with the source. In this paper, we address this problem by augmenting the state-of-the-art domain adaptation technique, Self-Ensembling, with category-agnostic clusters in target domain. Specifically, we …

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Secure Server-Aided Data Sharing Clique With Attestation, Yujue Wang, Hwee Hwa Pang, Robert H. Deng, Yong Ding, Qianhong Wu, Bo Qin, Kefeng Fan Jun 2020

Secure Server-Aided Data Sharing Clique With Attestation, Yujue Wang, Hwee Hwa Pang, Robert H. Deng, Yong Ding, Qianhong Wu, Bo Qin, Kefeng Fan

Research Collection School Of Computing and Information Systems

In this paper, we consider the security issues in data sharing cliques via remote server. We present a public key re-encryption scheme with delegated equality test on ciphertexts (PRE-DET). The scheme allows users to share outsourced data on the server without performing decryption-then-encryption procedures, allows new users to dynamically join the clique, allows clique users to attest the message underlying a ciphertext, and enables the server to partition outsourced user data without any further help of users after being delegated. We introduce the PRE-DET framework, propose a concrete construction and formally prove its security against five types of adversaries regarding …

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Quantum Random Walk Search And Grover's Algorithm - An Introduction And Neutral-Atom Approach, Anna Maria Houk Jun 2020

Quantum Random Walk Search And Grover's Algorithm - An Introduction And Neutral-Atom Approach, Anna Maria Houk

Physics

In the sub-field of quantum algorithms, physicists and computer scientist take classical computing algorithms and principles and see if there is a more efficient or faster approach implementable on a quantum computer, i.e. a ”quantum advantage”. We take random walks, a widely applicable group of classical algorithms, and move them into the quantum computing paradigm. Additionally, an introduction to a popular quantum search algorithm called Grover’s search is included to guide the reader to the development of a quantum search algorithm using quantum random walks. To close the gap between algorithm and hardware, we will look at using neutral-atom (also …

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What Do Undergraduate Engineering Students And Preservice Teachers Learn By Collaborating And Teaching Engineering And Coding Through Robotics?, Jennifer Jill Kidd, Krishnanand Kaipa, Samuel J. Jacks, Stacie I. Ringleb, Pilar Pazos, Kristie Gutierrez, Orlando M. Ayala, Lillian Maria De Souza Almeida Jun 2020

What Do Undergraduate Engineering Students And Preservice Teachers Learn By Collaborating And Teaching Engineering And Coding Through Robotics?, Jennifer Jill Kidd, Krishnanand Kaipa, Samuel J. Jacks, Stacie I. Ringleb, Pilar Pazos, Kristie Gutierrez, Orlando M. Ayala, Lillian Maria De Souza Almeida

Teaching & Learning Faculty Publications

This research paper presents preliminary results of an NSF-supported interdisciplinary collaboration between undergraduate engineering students and preservice teachers. The fields of engineering and elementary education share similar challenges when it comes to preparing undergraduate students for the new demands they will encounter in their profession. Engineering students need interprofessional skills that will help them value and negotiate the contributions of various disciplines while working on problems that require a multidisciplinary approach. Increasingly, the solutions to today's complex problems must integrate knowledge and practices from multiple disciplines and engineers must be able to recognize when expertise from outside their field can …

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Monte Carlo Tree Search Applied To A Modified Pursuit/Evasion Scotland Yard Game With Rendezvous Spaceflight Operation Applications, Joshua A. Daughtery Jun 2020

Monte Carlo Tree Search Applied To A Modified Pursuit/Evasion Scotland Yard Game With Rendezvous Spaceflight Operation Applications, Joshua A. Daughtery

Theses and Dissertations

This thesis takes the Scotland Yard board game and modifies its rules to mimic important aspects of space in order to facilitate the creation of artificial intelligence for space asset pursuit/evasion scenarios. Space has become a physical warfighting domain. To combat threats, an understanding of the tactics, techniques, and procedures must be captured and studied. Games and simulations are effective tools to capture data lacking historical context. Artificial intelligence and machine learning models can use simulations to develop proper defensive and offensive tactics, techniques, and procedures capable of protecting systems against potential threats. Monte Carlo Tree Search is a bandit-based …

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A Virtualization Based System Infrastructure For Dynamic Program Analysis, Jiaqi Hong Jun 2020

A Virtualization Based System Infrastructure For Dynamic Program Analysis, Jiaqi Hong

Dissertations and Theses Collection (Open Access)

Dynamic malware analysis schemes either run the target program as is in an isolated environment assisted by additional hardware facilities or modify it with instrumentation code statically or dynamically. The hardware-assisted schemes usually trap the target during its execution to a more privileged environment based on the available hardware events. The more privileged environment is not accessible by the untrusted kernel, thus this approach is often applied for transparent and secure kernel analysis. Nevertheless, the isolated environment induces a virtual address gap between the analyzer and the target, which hinders effective and efficient memory introspection and undermines the correctness of …

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Vision And Sensor-Based Signer-Independent Framework For Arabic Sign Language Recognition, Al-Shamayleh Ahmad Sami Abd Alkareem Jun 2020

Vision And Sensor-Based Signer-Independent Framework For Arabic Sign Language Recognition, Al-Shamayleh Ahmad Sami Abd Alkareem

Student Works (2020-2029)

Hearing and speech-impairment disability is widespread throughout the world. At present, 15 million people have this disability in the Arab world, and about 86% of them come from low- and middle-income countries. Meanwhile, sign language (SL) can be classified into standard Arabic sign language (ArSL) and local Arabic sign language (LArSL). ArSL is the formal standard and is the more acceptable SL in the Arab world; it is also considered as the medium of instructions for schools and universities as well as television news, shows and programmes. With the absence of usable ArSL recognition (ArSLR) platforms, hearing- and speech-impaired people …

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On The Relationship Between Developer Experience And Refactoring: An Exploratory Study And Preliminary Results, Eman Abdullah Alomar, Anthony Peruma, Christian D. Newman, Mohamed Wiem Mkaouer, Ali Ouni Jun 2020

On The Relationship Between Developer Experience And Refactoring: An Exploratory Study And Preliminary Results, Eman Abdullah Alomar, Anthony Peruma, Christian D. Newman, Mohamed Wiem Mkaouer, Ali Ouni

Articles

Refactoring is one of the means of managing technical debt and maintaining a healthy software structure through enforcing best design practices, or coping with design defects. Previous refactoring surveys have shown that these code restructurings are mainly executed by developers who have sufficient knowledge of the system’s design, and disposing of leadership roles in their development teams. However, these surveys were mainly limited to specific projects and companies. In this paper, we explore the generalizability of the previous results though analyzing 800 open-source projects. We mine their refactoring activities, and we identify their corresponding contributors. Then, we associate an expertise …

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Using Generative Adversarial Networks To Classify Structural Damage Caused By Earthquakes, Gian P. Delacruz Jun 2020

Using Generative Adversarial Networks To Classify Structural Damage Caused By Earthquakes, Gian P. Delacruz

Master's Theses

The amount of structural damage image data produced in the aftermath of an earthquake can be staggering. It is challenging for a few human volunteers to efficiently filter and tag these images with meaningful damage information. There are several solution to automate post-earthquake reconnaissance image tagging using Machine Learning (ML) solutions to classify each occurrence of damage per building material and structural member type. ML algorithms are data driven; improving with increased training data. Thanks to the vast amount of data available and advances in computer architectures, ML and in particular Deep Learning (DL) has become one of the most …

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Bubble-In Digital Testing System, Chaz Hampton Jun 2020

Bubble-In Digital Testing System, Chaz Hampton

Electronic Theses, Projects, and Dissertations

Bubble-In is a cloud-based test-taking system build for students and teachers. The Bubble-In system is a test-taking application that interfaces with a cloud server. The mobile applications have been built for Android and Apple devices and the webserver is hosted on Digital Ocean VPS run with Nginx. The Bubble-In application is equipped with anti-cheating mechanisms such as question-answer key scrambling, not allowing screenshots, screen recording, or leaving the application. The tests students take are sent to the webserver to be graded and have statistics calculated and displayed in easy to use format for the test creator. Instructors can use the …

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Real-Time Tracking And Mining Of Users’ Actions Over Social Media, Ejub Kajan, Noura Faci, Zakaria Maamar, Mohamed Sellami, Emir Ugljanin, Hamamache Kheddouci, Dragan H. Stojanović, Djamal Benslimane Jun 2020

Real-Time Tracking And Mining Of Users’ Actions Over Social Media, Ejub Kajan, Noura Faci, Zakaria Maamar, Mohamed Sellami, Emir Ugljanin, Hamamache Kheddouci, Dragan H. Stojanović, Djamal Benslimane

All Works

© 2020, ComSIS Consortium. All rights reserved. With the advent of Web 2.0 technologies and social media, companies are actively looking for ways to know and understand what users think and say about their products and services. Indeed, it has become the practice that users go online using social media like Facebook to raise concerns, make comments, and share recommendations. All these actions can be tracked in real-time and then mined using advanced techniques like data analytics and sentiment analysis. This paper discusses such tracking and mining through a system called Social Miner that allows companies to make decisions about …

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Learning Context-Aware Outfit Recommendation, Ahed Abugabah, Xiaochun Cheng, Jianfeng Wang Jun 2020

Learning Context-Aware Outfit Recommendation, Ahed Abugabah, Xiaochun Cheng, Jianfeng Wang

All Works

© 2020 by the authors. With the rapid development and increasing popularity of online shopping for fashion products, fashion recommendation plays an important role in daily online shopping scenes. Fashion is not only a commodity that is bought and sold but is also a visual language of sign, a nonverbal communication medium that exists between the wearers and viewers in a community. The key to fashion recommendation is to capture the semantics behind customers' fit feedback as well as fashion visual style. Existing methods have been developed with the item similarity demonstrated by user interactions like ratings and purchases. By …

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Mining User-Generated Content Of Mobile Patient Portal: Dimensions Of User Experience, Mohammad Al-Ramahi, Cherie Noteboom Jun 2020

Mining User-Generated Content Of Mobile Patient Portal: Dimensions Of User Experience, Mohammad Al-Ramahi, Cherie Noteboom

Research & Publications

Patient portals are positioned as a central component of patient engagement through the potential to change the physician-patient relationship and enable chronic disease self-management. The incorporation of patient portals provides the promise to deliver excellent quality, at optimized costs, while improving the health of the population. This study extends the existing literature by extracting dimensions related to the Mobile Patient Portal Use. We use a topic modeling approach to systematically analyze users’ feedback from the actual use of a common mobile patient portal, Epic’s MyChart. Comparing results of Latent Dirichlet Allocation analysis with those of human analysis validated the extracted …

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Simulation Modeling Method Of Distributed Supply Chain Based On Has, Wang Jian, Huang Yang Jun 2020

Simulation Modeling Method Of Distributed Supply Chain Based On Has, Wang Jian, Huang Yang

Journal of System Simulation

Abstract: There are some shortcomings in simulation modeling method of distributed supply chain based on High Level Architecture (HLA) and Supply Chain Operation Reference (SCOR), which result in low development efficiency of system simulation modeling and low reusability of simulation objects inside the federates. To solve the problems, a simulation modeling method of distributed supply chain based on HAS(HLA-Agent-SCOR) was put forward. The supply chain structure modeling based on HLA for building structure model of supply chain was discussed. Modeling of Agent blocks integrating processes from SCOR and modeling of federates based on Agent were illustrated to create model of …

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Multi-Robots Global Path Planning Based On Pso Algorithm And Cubic Spline, Qiang Ning, Gao Jie, Fengju Kang Jun 2020

Multi-Robots Global Path Planning Based On Pso Algorithm And Cubic Spline, Qiang Ning, Gao Jie, Fengju Kang

Journal of System Simulation

Abstract: There are shortcomings such as premature convergence, high encoding dimension and unsmooth path for particle swarm optimization (PSO) algorithm to solve the robot path planning problem under free space. The particle coding is coordinates of several path nodes in the environment. The number of spline curves and the maximum turnings of path were determined by the number of path nodes. The cubic spline function was used to interpolate on the path of the starting point, path nodes and target point, thus a full path which was formed by connecting all interpolation points was obtained. Simulation results show that …

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Improved Marching Cubes Algorithmand Its Three-Dimensional Meteorological Simulation, Shuoben Bi, Lu Yuan, Xiaowen Zeng, Mingyue Lu, Yonghua Zhang Jun 2020

Improved Marching Cubes Algorithmand Its Three-Dimensional Meteorological Simulation, Shuoben Bi, Lu Yuan, Xiaowen Zeng, Mingyue Lu, Yonghua Zhang

Journal of System Simulation

Abstract: Methodof obtaining intersection points of isosurface and vowex by linear interpolation in original Marching Cubes algorithm has been replaced by the method of trisecting element boundaries. The problem of linear interpolation not suitable for meteorological data simulation is therefore solved and the number of triangular facets in isosurfacemapping is effectively reduced. While reducing redundancy and improving mapping speed, the quality of isosurface mapping is further improved. The improved Marching Cubes algorithm is applied to the simulation of meteorological model data, i.e., the isosurface of WRF data, and good results are obtained in both the speed of image rendering and …

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Trajectory Capture And Sway Frequency Analysis Of Trees Based On Kinect, He Peng, Shaojun Hu, Dongjian He Jun 2020

Trajectory Capture And Sway Frequency Analysis Of Trees Based On Kinect, He Peng, Shaojun Hu, Dongjian He

Journal of System Simulation

Abstract: The morphology and structure of plants were complex. It is of great significance to investigate the inherent motion law of plants under the action of external force, such as realistic animation formation, plant pruning, vibration picking and forest protection. A low cost outdoor tree complex motion capture method was explored, and the relationship between the stem motion and the external force was analyzed. The Kinect was used to capture the branches motion; MeanShift algorithm was used for tracking branches markers and the three-dimensional trajectory of the trunk was extracted according to the principle of Kinect coordinate transformation. A method …

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Realistic Real-Time Road Rendering Technology Based On Road Boundaryalpha-Map, Jinlian Du, Shang Xin, Fengchao Zhao Jun 2020

Realistic Real-Time Road Rendering Technology Based On Road Boundaryalpha-Map, Jinlian Du, Shang Xin, Fengchao Zhao

Journal of System Simulation

Abstract: A method of realistic real-time rendering based on road boundary alpha-map was proposed to eliminate the blur and aliasing issues produced by traditional rendering method based on buffer mechanism. In the method, the road was generated by buffer mechanism based on grid model of terrain, and the road's borders were constructed by analyzing the characteristics of road boundary grids. Based on these, three types of road boundary alpha-maps were designed for producing the road borders with realistic visual effects. Experiment shows that the method can improve the rendering realism of the road borders than traditional method. Another advantage of …

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Simulation On Psychosocial Adaption Of Urban New Migrants Based On Catastrophe Theory, Zhao Xu, Chuanchao Huang, Bin Hu Jun 2020

Simulation On Psychosocial Adaption Of Urban New Migrants Based On Catastrophe Theory, Zhao Xu, Chuanchao Huang, Bin Hu

Journal of System Simulation

Abstract: Based on the mental recovery and adaptive behavior translation of the new urban migrants, a two system decision-making model for psychological adaption was built. The simulation research of psychosocial adaption process was studied through the stochastic catastrophe theory and the specific artificial social environment. Simulation experiments indicate that the sustained pressure-bearing suffers from outside situation and the policy system result in the fluctuation of migrants' psychosocial adaption with the former more significant. In the translation of adaptive psychology to adaptive behavior, the attitude orientation and psychological cognition of migrants are critical. The duration or degree of the adaptive process …

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Multiple Faults Identification Of Three-Level Inverter, Yanxia Shen, Wu Juan, Zhipu Zhao, Zhicheng Ji Jun 2020

Multiple Faults Identification Of Three-Level Inverter, Yanxia Shen, Wu Juan, Zhipu Zhao, Zhicheng Ji

Journal of System Simulation

Abstract: A three-level neutral point clamped (NPC) inverter was taken as an example, phase current and bridge voltage in the fault states of single switch open and several switches open at the same time were analyzed, and a method based on reconstructive phase space (RPS) and wavelet packet analysis was proposed to identify three-level inverter faults. Based on RPS method, totally different reconstructed current trajectories were obtained, which showed the features of the inverter under different fault conditions. With the help of image processing technology, all kinds of faults with different phase currents were identified. The wavelet packet analysis was …

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Simulation Of Joint Power Control Routing Algorithm For Interference And Energy Consumption In Crahns, Zhufang Kuang, Zhigang Chen Jun 2020

Simulation Of Joint Power Control Routing Algorithm For Interference And Energy Consumption In Crahns, Zhufang Kuang, Zhigang Chen

Journal of System Simulation

Abstract: Problems of interference power to primary user by secondary userand the secondary user's running out of energy under underlay spectrum access model in cognitive radio ad hoc networks (CRAHNs) were investigated. Joint power control, routing and spectrum (channel) allocation algorithm (PRSA) based on particle swarm optimization were proposed. The goal of PRSA was to minimize interference power to primary user and prolong lifetime of CRAHNs. Particle encoding, particle initialization, fitness function, particle flight were included in PRSA. An Adjacency matrix with two-tuples containing allocated channel and power level was designed, and three operation rules for particle were redefined. …

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