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Mining coterie patterns from Instagram photo trajectories for recommending popular travel routes

Frontiers of Computer Science 2017年第6期11卷 1007-1022页

作者： yaxin yu yuhai ZHAO Ge yu Guoren WANG Department of Computer Science School of Computer Science & Engineering Northeastern University Shenyang 110819 China

Abstract Instagram is a popular photo-sharing social ap- plication. It is widely used by tourists to record their journey information such as location, time and interest. Consequently, a huge volume of get-tagged photos with spatio-temporal in- formation are generated along tourist＇s travel trajectories. Such Instagram photo trajectories consist of travel paths, travel density distributions, and traveller behaviors, prefer- ences, and mobility patterns. Mining Instagram photo trajec- tories is thus very useful for many mobile and location-based social applications, including tour guide and recommender systems. However, we have not found any work that extracts interesting group-like travel trajectories from Instagram pho- tos asynchronously taken by different tourists. Motivated by this, we propose a novel concept： coterie, which reveals representative travel trajectory patterns hidden in Instagram photos taken by users at shared locations and paths. Our work includes the discovery of （1） coteries, （2） closed co- teries, and （3） the recommendation of popular travel routes based on closed coteries. For this, we first build a statistically reliable trajectory database from Instagram get-tagged pho- tos. These trajectories are then clustered by the DBSCAN method to find tourist density. Next, we transform each raw spatio-temporal trajectory into a sequence of clusters. All dis- criminative closed coteries are further identified by a Cluster- Growth algorithm. Finally, distance-aware and conformity- aware recommendation strategies are applied on closed co- teries to recommend popular tour routes. Visualized demosand extensive experimental results demonstrate the effective- ness and efficiency of our methods.

关键词： tourists coterie closed coterie geotagged pho-tos Instagram trajectories recommendation popular travelroutes

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Using Artificial Neural Networks for Energy Regulation Based Variable-speed Electrohydraulic Drive

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Chinese Journal of Mechanical Engineering 2010年第3期23卷 327-335页

作者： XU Ming JIN Bo yu yaxin SHEN Haikuo LI Wei The State Key Lab of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China College of Mechanical Engineering and Automation Zhejiang Sci-Tech University Hangzhou 310018 China

In the energy regulation based varibable-speed electrohydraulic drive system, the supply energy and the demanded energy, which will affect the control performance greatly, are crucial. However, they are hard to be obtained via conventional methods for some reasons. This paper tries to a new route： the definitive numerical values of the supply energy and the demanded energy are not required, except for their relationship which is called energy state. A three-layer back propagation（BP） neural network was built up to act as an energy analysis unit to deduce the energy state. The neural network has three inputs： the reference displacement, the actual displacement of cylinder rod and the system flowrate supply. The output of the neural network is energy state. A Chebyshev type II filter was designed to calculate the cylinder speed for the estimation of system flowrate supply. The training and testing samples of neural network were collected by the system accurate simulation model. After off-line training, the neural network was tested by the testing data. And the testing result demonstrates that the designed neural network was successful. Then, the neural network acts as the energy analysis unit in real-time experiments of cylinder position control, where it works efficiently under square-wave and sine-wave reference displacement. The experimental results validate its feasibility and adaptability. Only a position sensor and some pressure sensors, which are cheap and have quick dynamic response, are necessary for the system control. And the neural network plays the role of identifying the energy state.

关键词： neural network energy state energy regulation device variable-speed

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QUADRATIC OPTIMIZATION METHOD AND ITS APPLICATION ON OPTIMIZING MECHANISM PARAMETER

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Chinese Journal of Mechanical Engineering 2006年第4期19卷 519-523页

作者： ZHAO yun CHEN Jianneng yu yaxin yu Gaohong ZHU Jianping College of Mechanical Engineering and Automation Zhejiang Sci-Tech University Hangzhou 310018 China College of Biosystem Engineering and Food Science Zhejiang University Hangzhou 310029 China Modem Agricultural EquipmentHuzhou Combine Harvester Co. Ltd Huzhou 313000 China

In order that the mechanism designed meets the requirements of kinematics with optimal dynamics behaviors, a quadratic optimization method is proposed based on the different characteristics of kinematic and dynamic optimization. This method includes two steps of optimization, that is, kinematic and dynamic optimization. Meanwhile, it uses the results of the kinematic optimization as the constraint equations of dynamic optimization. This method is used in the parameters optimization of transplanting mechanism with elliptic planetary gears of high-speed rice seedling transplanter with remarkable significance. The parameters spectrum, which meets to the kinematic requirements, is obtained through visualized human-computer interactions in the kinematics optimization, and the optimal parameters are obtained based on improved genetic algorithm in dynamic optimization. In the dynamic optimization, the objective function is chosen as the optimal＇ dynamic behavior and the constraint equations are from the results of the kinematic optimization, This method is suitable for multi-objective optimization when both the kinematic and dynamic performances act as objective functions.

关键词： Quadratic optimization Parameter optimization Kinematics Dynamics

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Design and Experimental Research on Seedling Pick-Up Mechanism of Planetary Gear Train with Combined Non-circular Gear Transmission

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Chinese Journal of Mechanical Engineering 2019年第3期32卷 42-54页

作者： yaxin yu Jikun Liu Bingliang Ye Gaohong yu Xuejun Jin Liang Sun Junhua Tong College of Machinery and Automation Zhejiang Sci-Tech UniversityHangzhou 310018China Zhejiang Province Key Laboratory of Transplanting Equipment and Technology Hangzhou 310018China

Currently, transplanting mechanisms for dryland plug seedlings in China are mainly semiautomatic and have low efficiency. The rotary seedling pick-up mechanism with a planetary gear train for non-uniform intermittent transmission, and a concave and convex locking arc device, has a large rigid impact. To solve these problems, according to the design requirements for a dryland plug seedling transplanting mechanism, a rotary seedling pick-up mechanism of a planetary gear train with combined non-circular gear transmission of incomplete eccentric circular and noncircular gears was proposed. This has the characteristics of two-times greater fluctuation of the transmission ratio in a cycle, and can achieve a non-uniform continuous drive. Through analysis of the working principle of the seedling pick-up mechanism, its kinematics model was established. The human–computer interaction optimization method and self-developed computer-aided analysis and optimization software were used to obtain a set of parameters that satisfy the operation requirements of the seedling pick-up mechanism. According to the optimized parameters, the structure of the seedling pick-up mechanism was designed, a virtual prototype of the mechanism was created, and a physical prototype was manufactured. A virtual motion simulation of the mechanism was performed, high-speed photographic kinematics tests were conducted, and the kinematic properties of the physical prototype were investigated, whereby the correctness of the theoretical model and the optimized design of the mechanism were verified. Further, laboratory seedling pick-up tests were conducted. The success ratio of seedling pick-up was 93.8% when the seedling pick-up efficiency of the mechanism was 60 plants per minute per row, indicating that the mechanism has a high efficiency and success ratio for seedling pick-up and can be applied to a dryland plug seedling transplanter.

关键词： Dryland plug seedling transplanter Rotary seedling pick-up mechanism Transmission ratio Non-uniform continuous transmission Combined non-circular gear transmission Optimization design

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Design of clamping-pot-type planetary gear train transplanting mechanism for rice wide-narrow-row planting

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International Journal of Agricultural and Biological Engineering 2021年第2期14卷 62-71页

作者： Lei Wang Liang Sun Hengmin Huang yaxin yu Gaohong yu Faculty of Mechanical Engineering&Automation Zhejiang Sci-Tech UniversityHangzhou 310018China Zhejiang Province Key Laboratory of Transplanting Equipment and Technology Hangzhou 310018China

To design a clamping-pot-type wide-narrow-row pot seedling transplanting(WPST)mechanism with desired spatial beak-shaped trajectory and working posture,a new design method of planetary gear train transplanting mechanism(PGTM)with non-circular gears based on several key spatial poses(position and posture)was *** PGTM was simplified to a spatial open-loop chain with two-revolute(2R)*** geometric constraint equations containing only the structural parameters of the chain were then established on the basis of the three key spatial poses,and the homotopy algorithm was used to obtain all the required parameters of the *** accordance with the parameters obtained,the relative angular displacement relation between the planet carrier and the transplanting arm was optimized,the trajectory of the mechanism was replayed,and the total transmission ratio was *** degree of freedom of the spatial 2R mechanism was reduced by attaching to the unequal gear pair,and the transmission ratio was distributed in accordance with the gear type to realize the design of a non-circular gear pitch ***,a clamping-pot-type PGTM for rice WPST driven by the combination of planar non-circular and non-conical gears was designed,and virtual simulation and prototype test were *** showed that the simulation and prototype test trajectories were consistent with the desired *** the operating speeds of 50 r/min and 90 r/min,the success rates of seedling picking were 95.32%and 90.15%,respectively,which verified the feasibility of the theoretical *** method could provide a reference for the design of a spatial PGTM with nonuniform transmission.

关键词： rice pot seedling wide-narrow-row transplanting spatial trajectory planetary gear train non-circular gear

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Linked-Tree: An Aggregate Query Algorithm Based on Sliding Window over Data Stream

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Wuhan University Journal of Natural Sciences 2006年第5期11卷 1114-1119页

作者： yu yaxin WANG Guoren SU Dong ZHU Xinhua School of Computer Science and Engineering Northeastern University Shenyang 110004 I.iaoning China Neusoft Group Ltd Shenyang 110179 LiaoningChina

How to process aggregate queries over data streams efficiently and effectively have been becoming hot re search topics in both academic community and industrial community. Aiming at the issues, a novel Linked-tree algorithm based on sliding window is proposed in this paper. Due to the proposal of concept area, the Linked-tree algorithm reuses many primary results in last window and then avoids lots of unnecessary repeated comparison operations between two successive windows. As a result, execution efficiency of MAX query is improved dramatically. In addition, since the size of memory is relevant to the number of areas but irrelevant to the size of sliding window, memory is economized greatly. The extensive experimental results show that the performance of Linked-tree algorithm has significant improvement gains over the traditional SC （Simple Compared） algorithm and Ranked-tree algorithm.

关键词： data streams sliding window aggregate query area hop

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Stimuli-responsive photofunctional materials for green and security printing

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InfoMat 2021年第1期3卷 82-100页

作者： yun Ma yaxin yu Jiangang Li Shujuan Liu Wei Huang Qiang Zhao Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials(IAM)Nanjing University of Posts and Telecommunications(NUPT)NanjingChina Frontiers Science Center for Flexible Electronics(FSCFE) Shaanxi Institute of Flexible Electronics(SIFE)and Shaanxi Institute of Biomedical Materials and Engineering(SIBME)Northwestern Polytechnical University(NPU)Xi'anChina

Information recording on paper has always been the most important approach to keep records of human activity and to spread *** the progress of science and technology,paper with different functions should be exploited to conform to the increasing demands in various *** one aspect,traditional paper can only be used once,and using large amounts of paper causes deforestation,additional solid waste treatment,environmental pollution,and high energy ***,the development of rewritable paper that is environment-friendly,low cost,and can save resources is significant for green *** the other aspect,information leakage brings security issues,which may lead to severe consequences,such as war outbreak,economic loss,social problems,and so ***,the development of security printing has also attracted wide ***-responsive photofunctional materials that have reversible variations in absorption or emission in response to changes in the external environmental have a great potential for the achievement of green and security *** date,much progress has been made in these research *** paper lists different smart materials that respond to various external stimuli,such as light,water,pH,heat,and metal ions,and summarizes the recent advances towards green and security ***,we discuss the current challenges and future directions in this rapidly growing research *** is expected that this review article will stimulate and guide future studies for the advanced green and security printing.

关键词： green printing rewritable paper security printing stimuli-responsive photofunctional materials

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地理社交网络中重叠种子的广告博弈决策机制

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计算机研究与发展 2019年第6期56卷 1302-1311页

作者：于亚新王磊东北大学计算机科学与工程学院

作为社交影响最大化问题的重要应用之一,社交广告(或社交营销)已成为一个热门行业.其目标就是寻找k个最具影响力的种子节点,使产品公司利用成员间推介的“级联”效应推销产品.然而,由于所用数据集的限制,大多数现有影响力最大化问题的... 详细信息

作为社交影响最大化问题的重要应用之一,社交广告(或社交营销)已成为一个热门行业.其目标就是寻找k个最具影响力的种子节点,使产品公司利用成员间推介的“级联”效应推销产品.然而,由于所用数据集的限制,大多数现有影响力最大化问题的研究成果只能用于分析用户在虚拟世界中的行为,忽略了位置信息所起的作用.在信息传播过程中,用户间的距离也会对传播概率造成影响.因此,对地理社交网络中的位置敏感的影响力最大化(location-aware influence maximization,LAIM)问题进行了定义,并提出一种贪婪框架下考虑位置的影响力最大化算法,该算法将营销位置信息引入现有影响力最大化(influence maximization,IM)问题定义中,解决了传统IM中由于缺少位置信息所导致的传播范围与实际需求不符问题.此外,鉴于同一领域不可避免的竞争会引发种子重叠现象,从而导致种子个体不能实现预期传播范围,立足重叠种子角度,旨在对公司选择进行决策博弈并找到纳什均衡点,从而降低了种子集合的重叠率与影响力损失.实验结果验证了贪婪框架下考虑位置的影响力最大化算法和重叠种子下决策博弈策略的有效性.

关键词：地理社交网络位置敏感的影响力最大化问题重叠种子博弈论纳什均衡

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Xuebijing alters tumor necrosis factor-alpha, interleukin-1beta and p38 mitogen activated protein kinase content in a rat model of cardiac arrest following cardiopulmonary resuscitation

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Neural Regeneration Research 2011年第33期6卷 2573-2576页

作者： Haifeng Li Mingli Sun yaxin yu Xiaoliang Liu Emernenc.v Medicine. Second Branch of First Hosoital of Jilin University Chanclchun 130031 Jilin Province China

We established a rat model of cardiac arrest by clamping the endotracheal tube of adult rats at expiration. Twenty-four hours after cardiopulmonary resuscitation, nerve cell injury and expression of tumor necrosis factor-α, interleukin-1β, and p38 mitogen activated protein kinase content were increased. Rats injected with Xuebijing, a Chinese herb compound preparation, exhibited normal cellular structure and morphology, dense neuronal cytoplasm, and decreased tumor necrosis factor-α, interleukin-1β, and p38 mitogen activated protein kinase expression at 24 hours following cardiopulmonary resuscitation. These data suggest that Xuebijing can attenuate neuronal injury induced by hypoxia and reperfusion during cardiopulmonary resuscitation.

关键词： cardiac arrest brain tumor necrosis factor-α interleukin-1β p38 mitogen activated protein kinase Xuebijing cardiopulmonary resuscitation

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一种模糊变系数PID控制器及其在水轮机调速器中的应用

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中国机械工程 2007年第8期18卷 912-916页

作者：俞亚新金波浙江理工大学杭州310033 浙江大学流体传动及控制国家重点实验室杭州310027

根据水轮机调速器工况不断变化的特点,提出一种模糊变系数PID控制器,它以常规PID控制器为核心,利用模糊控制原理在线调整PID控制器的比例、积分及微分增益。通过水轮机调速器半物理仿真实验系统来检验该控制器的控制性能,并与普通的PID... 详细信息

根据水轮机调速器工况不断变化的特点,提出一种模糊变系数PID控制器,它以常规PID控制器为核心,利用模糊控制原理在线调整PID控制器的比例、积分及微分增益。通过水轮机调速器半物理仿真实验系统来检验该控制器的控制性能,并与普通的PID控制器进行比较,结果表明,该控制器有良好的控制性能,并具有抵抗系统参数变化的能力。该控制器算法简单,实时性强,适于微机调速器应用。

关键词：水轮机调速器 PID控制模糊控制参数自整定

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