The Establishment of the Projections of Four to Seven-Dimensional Rectangular Coordinate Systems into the Three-Dimensional Space

Starting from the finite rotation group,the author makes a penetrating study of 4 to 7-dimensional hypercube so that we have acquired the projection models of 4 to 7-dimeneional spatial rectangular coordinate systems into the three-dimensional space to have the 4 to 7-dimensional geometric figures demonstrated correctly.

Coordinated Control Architecture for Motion Management in ADAS Systems

Advanced driver assistance systems(ADAS) seek to provide drivers and passengers of automotive vehicles increased safety and comfort. Original equipment manufacturers are integrating and developing systems for distance keeping, lane keeping and changing and other functionalities. The modern automobile is a complex system of systems. How the functionalities of advanced driver assistance are implemented and coordinated across the systems of the vehicle is generally not made available to the wider research community by the developers and manufactures. This paper seeks to begin filling this gap by assembling open source physics models of the vehicle dynamics and ADAS command models. Additionally, in order to facilitate ADAS development and testing without having access to the details of ADAS, a coordinated control architecture for motion management is also proposed for distributing ADAS motion control commands over vehicle systems. The architecture is demonstrated in a case study where motion is coordinated between the steering and the braking systems, which are typically used only for a single functionality. The integrated vehicle and system dynamics using the coordinated control architecture are simulated for various driving tasks. It is seen that improved trajectory following can be achieved by the proposed coordinated control architecture. The models, simulations and control architecture are made available for open access.

Least squares fitting of coordinate parameters model

This paper starts with untime-diversification of the time-diversification deformation model and gives displacement distribution model of untime-diversification and simplifies further the study of deformation model. The paper discusses the problem of least squares fitting of coordinate parameters model—parameters of deformation model. During discussion, the basic means of cubic B splines and two steps of multidimensional disorder datum fitting are adopted which can make fitting function calculated mostly approximate coordinate parameters model and it can make calculation easier.

Unified Coordinate System Model for Performance Calculation of Fix-pad Journal Bearing with Different Pad Preload

Traditional model for calculating performance parameters of a fix-pad journal bearing leads to heavy workload, complicated and changeable formulae as it requires deriving various geometric formulae with different bearing types such as circular journal bearing, dislocated bearing and elliptic bearing. Considering different pad preload ratios for non-standard bearing, traditional model not only becomes more complicated but also reduces scalability and promotion of the calculation programs. For the complexly case of traditional model while dealing with various fix-pad journal bearings, unified coordinate system model for performance calculation of fix-pad journal bearing is presented in the paper. A unified coordinate system with the bearing center at the origin is established, and the eccentricity ratio and attitude angle of axis relative to each pad are calculated through the coordinates of journal center and each pad center. Geometric description of fix-pad journal bearing is unified in this model, which can be used for both various standard bearing and non-standard bearing with different pad preload ratios. Validity of this model is verified with an elliptical bearing. Performance of a non-standard four-leaf bearing with different pad preload ratios is calculated based on this model. The calculation result shows that increasing preload ratio of the pad 1 and keeping that of the left three pads constant improves bearing capacity, stiffness and damping coefficients. This research presents a unified coordinate system model unifies performance calculation of fix-pad journal bearings and studied a non-standard four-leaf bearing with different pad preload ratios, the research conclusions provides new methods for performance calculation of fix-pad journal bearings.

A Survey of Model Predictive Control Methods for Traffic Signal Control

Enhancing traffic efficiency and alleviating(even circumventing) traffic congestion with advanced traffic signal control(TSC) strategies are always the main issues to be addressed in urban transportation systems. Since model predictive control(MPC) has a lot of advantages in modeling complex dynamic systems, it has been widely studied in traffic signal control over the past 20 years. There is a need for an in-depth understanding of MPC-based TSC methods for traffic networks. Therefore, this paper presents the motivation of using MPC for TSC and how MPC-based TSC approaches are implemented to manage and control the dynamics of traffic flows both in urban road networks and freeway networks. Meanwhile, typical performance evaluation metrics, solution methods, examples of simulations,and applications related to MPC-based TSC approaches are reported. More importantly, this paper summarizes the recent developments and the research trends in coordination and control of traffic networks with MPC-based TSC approaches. Remaining challenges and open issues are discussed towards the end of this paper to discover potential future research directions.

2000-2020年黄河流域水-能源-粮食系统耦合协调时空演变特征

[目的]探讨黄河流域水—能源—粮食系统的耦合协调时空演化特征,可为定量评估流域高质量发展和区域可持续发展提供科学依据。[方法]通过耦合协调度模型分析水—能源—粮食系统的综合发展水平和耦合协调特征,并利用灰色关联度对各子系统内部指标进行排序,进而判断对水—能源—粮食系统耦合协调度的影响程度。[结果](1)黄河流域水—能源—粮食系统的综合发展指数呈上升趋势,水资源子系统波动幅度最大。(2) 2000—2020年黄河流域水—能源—粮食系统耦合协调度从初级协调向良好协调阶段发展;不同省区间的系统耦合协调发展水平差异较为明显,整体上可表现为上游地区>中下游地区。(3)各子系统与系统耦合协调度的影响程度排名可表示为水资源子系统>粮食子系统>能源子系统,其中水资源子系统内部指标与系统耦合协调度关联度均在85%以上,水资源子系统相对其他子系统的严格管理尤为重要。[结论]水—能源—粮食系统的耦合协调发展水平有待提高,为促进系统协调发展和流域高质量发展应综合考虑各子系统的相互作用关系。

黄河流域城市群新型城镇化与生态安全协调发展研究

为推进中国式现代化建设,统筹黄河流域生态保护和高质量发展,提升城市群新型城镇化与生态安全协调发展水平,以黄河流域内的7个城市群为研究对象,构建新型城镇化与生态安全评价指标体系,运用耦合协调度模型和相对发展模型,并结合时空演化过程分析了黄河流域城市群新型城镇化与生态安全耦合协调度发展格局,最后通过系统动力学模型模拟未来5年耦合协调发展趋势.结果表明,研究期内,黄河流域城市群新型城镇化与生态安全耦合协调度总体呈上升趋势,部分城市群出现轻度波动,耦合协调特征由失调、濒临协调转化为勉强协调、初级协调;最后通过预测未来5年黄河流域城市群新型城镇化与生态安全耦合协调度发展过程,推断城市群均处于显著提升状态,且逐步达到初级协调阶段.针对目前黄河流域城市群新型城镇化与生态安全协调发展存在的不足,提出了相应的对策建议.

Francis Turbine and Governor Improved Models Considering Step Closing Law of Guide Vanes for Power System Stability Analysis

The Francis turbine governing system models in PSD-BPA can’t precisely reflect the actual characteristics. Endeavor was done in this paper to solve the problem. An improved model of actuating mechanism was developed, which could reflect the step closing characteristic of hydro guide vanes. The effect of the inflection point value of actuating mechanism on load rejection was analyzed based on simulation. The non-linear Francis turbine model with power versus gate position module was researched in this paper. Based on field test, comparisons of simulation results with measured data were presented. The analysis demonstrates that the improved models of Francis turbine and governor proposed in this paper are more realistic than the models of BPA, and can be applied in power system simulation analysis better.

浙江省数字经济与绿色发展耦合协调关系测度及政策启示

绿色发展与数字经济的有机融合是实现区域高质量发展的重要途径。本文以浙江省11个地级市为典型案例区,构建了包含7个子系统、37个指标的绿色发展与数字经济评价指标体系,采用改进的耦合协调度模型对2014—2020年数字经济和绿色发展系统的耦合协调关系进行关系测度,以期为区域可持续发展决策提供参考。结果发现:(1)绿色发展系统与数字经济系统综合发展水平总体都呈现上升趋势,除了杭州外,其他城市均表现数字经济发展水平滞后于绿色发展水平。(2)杭州是浙江省的绿色发展和数字经济“领头羊”,并在2019年率先进入高级协调阶段,其余10个城市仍处于初级协调阶段。未来,需注重城市间的差异性发展和重点扶持数字基础设施的投入建设。

V Model of E-Learning Using Gagne Nine Steps of Education

This paper presents a V-model of e-learning using the well-known Gagne nine steps for quality education. Our suggested model is based on our experience at the computer engineering departments at AL-Hussein Bin Talal University, the University of Jordan and Albalqa Applied University. We applied the recommendations of the nine steps methodology to the e-learning environment. The V model suggested in this paper came up as a result of such application. Although this V model can be subject to some tuning and development in the future it proved to be highly efficient and easy to implement for the teacher and the student.

生物质循环流化床机组协调系统模型研究

针对生物质循环流化床(CFB)机组,通过机理分析,研究了生物质燃烧的动态过程,建立了生物质CFB锅炉燃料侧燃烧模型。通过能量守恒,确定了生物质CFB机组汽水侧和汽机侧主要参数之间的函数关系,建立了负荷控制系统模型。基于某30 MW生物质CFB机组实际运行数据,通过稳态工况推导、回归分析和遗传算法辨识了模型的参数和函数关系,在Simulink软件平台验证了模型的结果并进行了模型阶跃试验。结果表明:模型的输出与实际数据能较好地吻合,主蒸汽压力、负荷的平均相对误差均在4%以内,阶跃响应符合实际经验,证明建立的模型能够反映机组的动态特性。

基于陆海统筹的资源环境承载力评价方法探讨

海洋、海岸带蕴含的资源丰富,与人类生存发展息息相关。近年来,随着海洋经济的迅速增长,自然岸线和滨海湿地面积减少、生物多样性降低、典型生态系统受损、近岸海域灾害频发、渔业资源减少等问题日益显现。如何从战略高度提升海洋经济,开发和保护并举,确保海岸带、海洋资源取用合理是新时代的重要课题。陆地和海洋是生态系统不可分割的组成部分,开展陆海统筹的资源环境承载力评价是衡量区域经济发展与生态环境是否协调可持续发展的有效途径。文章系统地梳理了承载力概念的发展历程,对比了常用的海洋资源环境承载力评价方法,初步构建了陆海统筹的资源环境承载力评价指标体系,并提出使用熵值法来确定指标权重,采用状态空间评价模型或TOPSIS模型进行承载力综合评价,可以体现陆地和海洋相互影响、相互制约的关系,并具有较强的可操作性,评价结果可以反映区域资源环境承载力的空间差异或随时间变化情况,能够为海洋和海岸带保护利用提供有效借鉴。

Energy Factor and Mathematical Modeling for Power DC/DC Converters

Mathematical modelling for power DC/DC converters is a historical problem accompanying DC/DC conversion technology since 1940’s. The traditional mathematical modelling is not available for complex structure converters since the differential equation order increases very high. We have to search other way to establish mathematical modelling for power DC/DC converters.We have theoretically defined a new concept-Energy Factor （EF） in this paper and researched the relations between EF and the mathematical modelling for power DC/DC converters. EF is a new concept in power DC/DC conversion technology, which thoroughly differs from the traditional concepts such as power factor （PF）, power transfer efficiency （η）, total harmonic distortion （THD） and ripple factor （RF）. EF and the subsequential EFV (and EFVD) can illustrate the system stability, reference response and interference recovery. This investigation is very helpful for system design and DC/DC converters characteristics foreseeing. Two DC/DC converters: Buck converter and Super-Lift Luo-Converter as the samples are analysed in this paper to demonstrate the applications of EF, EFV (and EFVD), PE, SE, VE （and VED）, time constant τ and damping time constant τd.

中国内地GPS坐标时间序列噪声模型特征及其对站点速率影响

为了进一步评估全球定位系统(GPS)时间序列噪声模型水平和垂直速率的大小,及其对误差的影响,选取中国内地227个GPS连续基准站2010—2020年南北、东西和垂直3个方向的坐标时间序列,采用6种噪声模型或噪声组合模型对其进行噪声分析。结果表明,中国内地GPS坐标时间序列噪声模型存在多样性,且部分站点在不同方向的噪声模型也存在差异,主要以一阶高斯马尔可夫+随机漫步噪声(GGMWN)和闪烁噪声+白噪声(FNWN)为主;在100°E附近的GPS站点噪声特性差异最为显著;噪声模型与速率之间的关系分析表明噪声模型对水平向速率的大小和误差影响较小,在现实计算中可不考虑噪声对水平速度的影响,但对垂向速率的大小和误差影响显著;考虑噪声模型可有效提高垂向速率的精度,同时也可能会改变部分站点的垂向运动方向,所以在现实计算中须考虑噪声对垂向速率的影响。

基于SFIC模型的养老事业与养老产业协同发展路径研究

养老事业与养老产业同属于养老服务体系的组成部分,充分发挥其作用重在二者协同发展,即二者相互协作实现养老服务的充分供给且达到二者共同发展的双赢效果。通过创新性地将SFIC模型用于养老服务体系发展分析,构建养老事业与养老产业协同发展分析框架,从星光老年之家、公建民营养老机构、政府购买养老服务、长期护理保险制度试点四个案例比较剖析养老事业与养老产业协同的起始条件、助成性领导、制度设计、合作程序,提出改善养老事业与养老产业协同发展的起始条件、发挥助成性领导对养老事业与养老产业协同发展的创造性作用、优化养老事业与养老产业协同发展的制度设计、在养老事业与养老产业协同发展中实现良性合作四个养老事业与养老产业协同发展的路径。

计及风电PSS与PLL耦合对功角振荡影响的DFIG控制参数协调优化

双馈感应发电机(doubly fed induction generator,DFIG)装设电力系统稳定器(power system stabilizer,PSS),有助于抑制同步发电机间功角振荡,但抑制效果受DFIG锁相环(phase-locked loop,PLL)跟踪误差影响。考虑PSS与PLL耦合特性对功角振荡的影响,提出改善振荡抑制效果的DFIG控制参数协调优化算法。首先基于DFIG有功控制的分解等效结构绘制DFIG-PSS与锁相误差的耦合路径,提出耦合特性解析表达。然后建立耦合解析表达对控制参数的轨迹灵敏度向量,以向量2-范数之比定义耦合强度,量化耦合特性对功角振荡的影响程度。最后基于耦合强度指标,提出带有PLL参数动态不等式约束的多步优化模型,以协调DFIG控制参数取值,提高并网系统对功角振荡的抑制效果。仿真结果证实了耦合特性对功角振荡的影响,验证了所提协调优化算法的有效性。

Mathematical Modeling of Heat Flux Distribution in Raw Cotton Stored in Bunt

The scientific article examines the physical and mechanical properties of raw cotton stored in buntings in cotton palaces. Because during the storage of raw cotton in bunts, some of its properties deteriorate, some improvements. Therefore, the mathematical modeling of storage conditions of raw cotton in bunts and the physical and mechanical conditions that occur in it is of great importance. In the developed mathematical model, the main factor influencing the physical and mechanical properties of raw cotton is the change in temperature. Due to the temperature, kinetic and biological processes accumulated in the raw cotton in Bunt, it can spread over a large surface, first in a small-local state, over time with a nonlinear law. As a result, small changes in temperature lead to a qualitative change in physical properties. In determining the law of temperature distribution in the raw cotton in Bunt, Laplace’s differential equation of heat transfer was used. The differential equation of heat transfer in Laplace’s law was replaced by a system of ordinary differential equations by approximation. Conditions are solved in MAPLE-17 program by numerical method. As a result, graphs of temperature changes over time in raw cotton were obtained. In addition, the table shows the changes in density, pressure and mass of cotton, the height of the bun. As the density of the cotton raw material increases from the top layer of the bunt to the bottom layer, an increase in the temperature in it has been observed. This leads to overheating of the bottom layer of cotton and is the main reason for the deterioration of the quality of raw materials.

改进PCA方法的牙颌特征提取和数据集构建

为了提高牙颌数字模型特征提取的准确性和牙齿分割的效率,提出一种几何变换和主成分分析相结合的坐标系标准化方法,并以离散曲率、法向量、形状直径函数和离散测地距离为基础特征对牙颌数字模型进行了特征提取,在此基础上进一步扩展构建了76个特征数据集。采用提出的坐标系标准化方法和数据集对上颌进行了牙齿分割实验。结果表明:改进主成分分析方法能够快速准确地实现牙颌数字模型坐标系对齐,能够准确识别牙齿的特征信息并作出标记,牙齿分割完整,平均分割准确率达到99.74%。基于改进主成分分析方法的牙颌模型特征提取方法能够极大地提高特征对牙齿的区分性,从而降低位姿对牙颌特征提取带来的负面影响,实现在特征数据较少的情况下准确分割牙齿,可为数字化口腔诊疗提供一定的参考。