Robust Fingerprint Construction Based on Multiple Path Loss Model (M-PLM) for Indoor Localization

A robust radio map is essential in implementing a fingerprint-based indoor positioning system(IPS).However,the offline site survey to manually construct the radio map is time-consuming and labour-intensive.Various interpolation techniques have been proposed to infer the virtual fingerprints to reduce the time and effort required for offline site surveys.This paper presents a novel fingerprint interpolator using a multi-path loss model(MPLM)to create the virtual fingerprints from the collected sample data based on different signal paths from different access points(APs).Based on the historical signal data,the poor signal paths are identified using their standard deviations.The proposed method reduces the positioning errors by smoothing out the wireless signal fluctuations and stabilizing the signals for those poor signal paths.By consideringmultipath signal propagations from different APs,the inherent noise from these signal paths can be alleviated.Firstly,locations of the signal data with standard deviations higher than the threshold are identified.The new fingerprints are then generated at these locations based on the proposed M-PLM interpolation function to replace the old fingerprints.The proposed technique interpolates virtual fingerprints based on good signal paths with more stable signals to improve the positioning performance.Experimental results show that the proposed scheme enhances the positioning accuracy by up to 44%compared to the conventional interpolation techniques such as the Inverse DistanceWeighting,Kriging,and single Path LossModel.As a result,we can overcome the site survey problems for IPS by building an accurate radio map with more reliable signals to improve indoor positioning performance.

Numerical Method for Modeling the Constitutive Relationship of Sand under Different Stress Paths

A numerical method was used in order to establish the constitutive relationship of sands under different stress paths, Firstly, based on the numerical method modeling the constitutive law of sands, the elastoplastic constitutive relationship of sand was established for three paths： the constant proportion of principle stress path, the conventional triaxial compression （CTC） path, and the p=constant （TC） path. The yield lines of plastic volumetric strain and plastic generalized shear strain were given. Through visualization, the three dimensional surface of the stress-strain relationship in the whole stress field （p, q） obtained under the three paths was plotted. Also, by comparing the stress-strain surfaces and yield locus of the three stress paths, the differences were found to be obvious, which demonstrates that the influence of the stress paths on constitutive law was not neglected. The numerical modeling method overcame the difficulty of finding an analytical expression for plastic potential. The results simulated the experimental data with an accuracy of 90% on average, so the constitutive model established in this paper provides an effective constitutive equation for this kind of engineering, reflecting the effect of practical stress paths that occur in sands.

Path Classification and Estimation Model Based Prognosis of Pneumatic Cylinder Lifetime

Prognosis is a key technology to improve reliability,safety and maintainability of products,a lot of researchers have been devoted to this technology.But to improve the predict accuracy of remaining life of products has been difficult.To predict the lifetime specification of pneumatic cylinders with high reliability and long lifetime and small specimen,this paper put forward the prognosis algorithm based on the path classification and estimation（PACE） model.PACE model is based entirely on failure data instead of failure threshold.Pneumatic cylinders normally characterize with failure mechanism wear and tear.Since the minimum working pressure increases with the number of working cycles,the minimum working pressure is chosen as degradation signal.PACE model is fundamentally composed of two operations：path classification and remaining useful life（RUL） estimation.Path classification is to classify a current degradation path as belonging to one or more of previously collected exemplary degradation paths.RUL estimation is to use the resulting memberships to estimate the remaining useful life.In order for verification and validation of PACE prognostic method,six pneumatic cylinders are tested.The test data is analyzed by PACE prognostics.It is found that the PACE based prognosis method has higher prediction accuracy and smaller variance and PACE model is significantly outperform population based prognostics especially for small specimen condition.PACE model based method solved the problem of prediction accuracy for small specimen pneumatic cylinders＇ prognosis.

Non-smooth environment modeling and global path planning for mobile robots

An Approximate Voronoi Boundary Network is constructed as the environmental model by way of enlar-ging the obstacle raster. The connectivity of the path network under complex environment is ensured through build-ing the second order Approximate Voronoi Boundary Network after adding virtual obstacles at joint-close grids. Thismethod embodies the network structure of the free area of environment with less nodes, so the complexity of pathplanning problem is reduced largely. An optimized path for mobile robot under complex environment is obtainedthrough the Genetic Algorithm based on the elitist rule and re-optimized by using the path-tightening method. Sincethe elitist one has the only authority of crossover, the management of one group becomes simple, which makes forobtaining the optimized path quickly. The Approximate Voronoi Boundary Network has a good tolerance to the im-precise a priori information and the noises of sensors under complex environment. Especially it is robust in dealingwith the local or partial changes, so a small quantity of dynamic obstacles is difficult to alter the overall character ofits connectivity, which means that it can also be adopted in dynamic environment by fusing the local path planning.

Green development model and cultivating path for characteristic small town

In the context of the new urbanization,the characteristic town,as a new hotspot to developing rapidly to explore the industry,humanities,community integration town model,a urbanization and high-tech industry development booster,by the government and developers attention.At the same time,the green development model applies to the characteristic town of industrial upgrading and transformation,guiding the future characteristic town of green economic industry development direction.This paper studies the green development model of the characteristic town,and puts forward the implementation of the green industry through the greening industry structure,promoting green consumption and optimizing the green management.

Path following control of underactuated ships based on nonswitch analytic model predictive control

A path following controller is developed for underactuated ships with only surge force and yaw moment available to follow a predefined path.The proposed controller is based on nonswitch analytic model predictive control.It is shown that the optimal control law for a nonlinear path following system with ill-defined relative degree is continuous and nonsingular.The problem of ill-defined relative degree is solved.The path-following ability of the nonlinear system is guaranteed.Numerical simulations are provided to demonstrate the effectiveness of the proposed control law.

Modeling of UAV path planning based on IMM under POMDP framework

In order to enhance the capability of tracking targets autonomously of unmanned aerial vehicle (UAV), the partially observable Markov decision process (POMDP) model for UAV path planning is established based on the POMDP framework. The elements of the POMDP model are analyzed and described. The state transfer law in the model can be described by the method of interactive multiple model (IMM) due to the diversity of the target motion law, which is used to switch the motion model to accommodate target maneuvers, and hence improving the tracking accuracy. The simulation results show that the model can achieve efficient planning for the UAV route, and effective tracking for the target. Furthermore, the path planned by this model is more reasonable and efficient than that by using the single state transition law.

Modified Ceiling Bounce Model for Computing Path Loss and Delay Spread in Indoor Optical Wireless Systems

This paper proposes modifications to the tradional Ceiling Bounce Model and uses it to characterize diffuse indoor optical wireless channel by analyzing the effect of transceiver position on signal propagation properties. The modified approach uses a combination of the tradional ceiling bounce method and a statistical approach. The effects of different transmitter-receiver separations and height of the ceiling on path loss and delay spread are studied in detail.

Indoor Radio Propagation Model Based on Dominant Path

When there are bigger obstacles in the indoor environment such as elevator, the radio waves basically can not penetrate it. The contribution of received signal strength by transmission and reflection will be greatly reduced, and most of the time, the radio waves will reach the user by bypass diffraction. Therefore, the traditional path loss model is no longer applicable, and the improved model should be proposed. In this paper, we firstly proposed an indoor radio propagation model based on dominant path in which the received signal strength has nothing to do with the direct distance between user and access point, but is related to the length of dominant path. Then on the basis of dominant path model, the NLOS influence is considered in order to further improve the accuracy of dominant path model. Experimental results demonstrated that the proposed dominant path model can improve the accuracy of traditional path loss model remarkably.

Cybersecurity: A Statistical Predictive Model for the Expected Path Length

The object of this study is to propose a statistical model for predicting the Expected Path Length (expected number of steps the attacker will take, starting from the initial state to compromise the security goal—EPL) in a cyber-attack. The model we developed is based on utilizing vulnerability information along with having host centric attack graph. Utilizing the developed model, one can identify the interaction among the vulnerabilities and individual variables (risk factors) that drive the Expected Path Length. Gaining a better understanding of the relationship between vulnerabilities and their interactions can provide security administrators a better view and an understanding of their security status. In addition, we have also ranked the attributable variables and their contribution in estimating the subject length. Thus, one can utilize the ranking process to take precautions and actions to minimize Expected Path Length.

Calculation of the Model of Coesite Inclusions and Analysis of Their Retrometamorphic Paths

The process and path of retrometamorphism of coesite have great significance to our understanding of the P-T tracks of the exhumation of ultrahigh-pressure metamorphic rocks. Most of the coesites in the eclogite from Shima, Anhui Province, the Dabie Mountains, China, are found degraded to quartz partly or wholly, with ruptures occurring in the shells, outside which include the coesite and quartz. According to the microscopic observation, the sample of coesite inclusion is composed of garnet, quartz and coesite, based on which we have built a three-shelled composite sphere model to compute the transition of coesite. Based on the crystal growth formulas and pressure conditions of the ruptures in the garnet, we have calculated the radius of the quartz sphere, which depends on temperature, and eventually drawn the different retrometamorphic paths for different retrometamorphism rates.

数字融合背景下大学生数字素养培育:模型与路径

大学生数字素养培育是推进高等教育专业建设的必要举措,是助力高等教育数字化转型的重要议题。数字素养是包含知识、技能、特质、态度、伦理等要素的数字能力体系。该文从大学生群体出发,构建了数字素养陀螺模型,涵盖了多元知识、实践技能、个性特质、态度动机和道德伦理五个维度。基于此,立足于高等教育专业建设和数字化转型的背景,有针对性地提出大学生数字素养培育的路径:丰富数字资源供给,编制多元知识专业教材;强化数字培训力度,提升实践技能研习成效;加强个性特质培养,搭建虚实融合学习场景;重视数字意识培植,激活强化主体态度动机;拓展数字伦理边界,架构数字道德评价机制。

Bi-objective path optimization of flapping airfoils based on a surrogate model

A bi-objective optimization problem for flapping airfoils is solved to maximize the time-averaged thrust coefficient and the propulsive efficiency. Design variables include the plunging amplitude, the pitching amplitude and the phase shift angle. A well defined Kriging model is used to substitute the time-consuming high fidelity model, and a multi-objective genetic algorithm is employed as the search algorithm. The optimization results show that the propulsive efficiency can be improved by reducing the plunging amplitude and the phase shift angle in a proper way. The results of global sensitivity analysis using the Sobol’s method show that both of the time-averaged thrust coefficient and the propulsive efficiency are most sensitive to the plunging amplitude, and second most sensitive to the pitching amplitude. It is also observed that the phase shift angle has an un-negligible influence on the propulsive efficiency, and has little effect on the time-averaged thrust coefficient.

Modeling and Kinematics Simulation of Hydro-mechanical Split Path Steering Device of Tracked Vehicle Based on CATIA

Based on the working principle of hydro-mechanical split path of tracked vehicle, a operating gear was developed which was controlled by steering wheel and match with transmission case. Then CATIA software was used to build the three-dimensional model and carry out dynamic simulation of the mechanism. The result indicates that the design of the mechanism fulfills the request.

基于演化博弈的我国分级诊疗策略分析

目的在分级诊疗制度中涉及政府、医院和患者之间的利益关系,探讨三方动态博弈策略,有利于完善分级诊疗的理论范式和政策逻辑。方法构建政府、医院和患者三方模型,分析其策略选择及演化路径,求解三方演化博弈的稳定策略,探究如何进行利益平衡和合作以实现三方共赢。另外,利用Matlab R2018b对模型进行仿真,进一步分析三方主体的演化路径以及不同策略选择对分级诊疗制度推广的影响。结果政府、医院和患者3个主体的决策行为之间相互影响,最终将演化至点(1,1,1)的理想稳定状态。增大政府补贴会加速医院和患者的初始参与概率值收敛至1,但过多的补贴会使政府逐渐背离鼓励分级诊疗的策略。结论政府应在成本范围内加大对医院优质医疗资源下沉的专家补贴力度,并加强政府监管。大型医院和基层医疗卫生机构重要的是实现医生资源的自由流动和合理分布。患者还需转变固有的就医观念,才能最终实现有序就医。

基于空间句法的矿井应急疏散研究与应用

地下矿井作业危险,空间拓扑结构复杂,因而矿山安全事故时有发生,合理的应急疏散路线规划以及疏散指示布置,能够有效提高井下人员的逃生效率,降低人员伤亡与财产损失。结合某地下矿井实例,基于空间句法和GIS网络分析搭建地下矿井巷道网络模型,从逃生人员的空间认知角度出发,利用标准化角度选择度值选取巷道网络模型中的前景网络和背景网络作为主要避险通道,为应急疏散指示标志布置提供参考;考虑巷道宽度、巷道类型、巷道坡度等巷道基础属性信息,并结合空间句法指标——标准化角度整合度,构建巷道网络应急脆弱模型,顾及巷道空间单元的稳定性,规划井下人员的最优认知路径,进而实现了多目标的地下矿井紧急疏散路线规划。该研究不仅能够为地下矿井的巷道布局设计提供建议,还可为地下矿井的应急疏散路线规划辅助决策、应急预案制定提供理论依据,同时为紧急避险系统的建设与完善提供新的思路。

老年人驾驶暴露行为影响因素交互作用分析

年龄增长带来的身体机能衰退迫使老年人调整驾驶行为,自我调节作为补偿老年人健康状况和降低驾驶风险的策略,能够有效延长驾驶时间和降低驾驶风险。为探究老年人个人生理心理因素和社会环境因素对自我调节中驾驶暴露行为的影响,设计问卷并在昆明市开展调查,回收老年人出行调查问卷后对问卷数据进行分析处理,采用Cronbachα信度系数、KMO测度值和验证性因子检验问卷信度效度。统计分析发现,不同年龄段和就业情况的老年驾驶人在驾驶暴露行为上存在显著差异,病史和药物服用会影响老年人驾驶暴露行为,老年人对短距离的频繁出行更有信心。通过构建中介效应分析和结构方程模型探究老年驾驶人驾驶暴露行为影响因素,结果表明:年龄与驾驶暴露行为(r=-0.157^(**),p<0.05)呈显著负相关,驾驶能力与驾驶暴露行为(r=0.182^(**),p<0.05)呈显著正相关;驾驶能力在社会支持和驾驶暴露行为之间起完全中介作用。

数字人文时代下档案开发利用的新模式与新路径探索

档案作为承载和凝结人类社会历史记忆与文化遗产的优质载体,在数字人文理念和研究方法的驱动下,档案开发利用的创新转型迎来新机遇。在识别与分析数字人文环境下档案资源开发利用新需求与新特点的基础上,提炼档案开发利用模式创新的新思路,探索推动档案开发利用变革的新路径。在数字人文时代,档案开发利用呈现数字化和语义化的资源深加工、知识图谱驱动的语义关联组织、虚实融合的情境化呈现、众创众包的社会协同利用等新模式。推动档案开发利用变革与转型,需要从构建数据基础设施、建立跨学科研究服务团队、深度运用前沿数智技术、拓展虚实融合服务空间、打造“档案+数字人文”品牌等方面统筹谋划、协同发力。未来,档案工作要以开放创新的视野,积极投身数字人文实践,在传承优秀传统文化、服务经济社会发展中彰显档案新价值。

无人驾驶农机避障路径跟踪仿真与验证

【目的】为便于验证无人驾驶农机避障路径跟踪的效果,减少实际无人农机试验次数与消耗,设计一种无人驾驶农机避障路径跟踪仿真验证方法,构建一个仿真验证应用系统。【方法】以无人农机为基础,集成真实复杂地形环境仿真、实际作业农机仿真和路径规划算法植入,构建一个一体化仿真验证应用系统。基于三维SLAM技术,采集环境点云数据,实现农田地形环境仿真建模,构建阿克曼转向机械结构的农机仿真建模,提出一种基于农机动力学约束的TEB局部路径规划算法;在仿真验证应用系统中实现路径规划跟踪及避障,并通过多次测试验证该算法的有效性。【结果】避障路径跟踪有效性对比测试和避障路径跟踪平顺性验证测试结果表明,无人农机行驶过程中可有效动态避障,最短有效避障距离为4.1 m。路径跟踪控制效果良好,障碍物距离大于5.0 m时,可控平均误差≤0.4305 m,均方根误差≤0.3151 m;障碍物距离在4.5~5.0 m时,可控误差均值≤1.3538 m,均方根误差≤1.6126 m。【结论】本文提出的改进TEB算法具有较强的作业能力以及较高的作业精度,满足农业机械导航避障路径跟踪仿真验证的需求,该算法可应用于无人农机在实际农田环境的避障路径跟踪。该应用系统易于扩充,为精准农业中针对各种复杂作业环境的农机运作状态的优化设计研究提供基础。

乡村景观治理模式的演变路径及动力学机制研究

运用历史比较法、内容分析法,对中华人民共和国成立以来我国乡村景观及其治理体系的演进历程进行全景式分析。将治理模式分为起步阶段、改革阶段和完善阶段,结合各时期乡村景观建设成效,归纳治理影响因素与对景观的调节机制,认为国家对乡村的定位决定景观治理目标与重点,土地、人口管理、经济产业等制度改革引导乡村治理的潜力挖掘,行政财政体制制约乡镇的治理效能,社会文化嬗变加速治理程序的价值转向。最后,基于演变路径提出建议,以期探索更加规范化、法制化的乡村景观建设与治理模式。