Functionality Semantics of Predicate Data Flow Diagram

SOZL (structured methodology + object-oriented methodology + Z language) is a language that attempts to integrate structured method, object-oriented method and formal method. The core of this language is predicate data flow diagram (PDFD). In order to eliminate the ambiguity of predicate data flow diagrams and their associated textual specifications, a formalization of the syntax and semantics of predicate data flow diagrams is necessary. In this paper we use Z notation to define an abstract syntax and the related structural constraints for the PDFD notation, and provide it with an axiomatic semantics based on the concept of data availability and functionality of predicate operation. Finally, an example is given to establish functionality consistent decomposition on hierarchical PDFD (HPDFD).

A New Synthetical Knowledge Representation Model and Its Application in Data Flow Diagram

A new synthetical knowledge representation model that integrates the attribute grammar model with the semantic network model was presented. The model mainly uses symbols of attribute grammar to establish a set of syntax and semantic rules suitable for a semantic network. Based on the model,the paper introduces a formal method defining data flow diagrams (DFD) and also simply explains how to use the method.

Tectonic Implications of the Combined Use of Tectonomagmatic Geochemical Discrimination Diagrams and Indicators of Magma Flow Sense in Mafic Dykes

Geochemistry is a powerful tool to help characterize the tectonic setting of igneous rocks associations.However,when continental mafic dykes and flood basalts are the target most of the proposed geochemical discrimination diagrams fail to correctly classify them,i.e.many mafic

DFDVis:A Visual Analytics System for Understanding the Semantics of Data Flow Diagram

Data flow diagram(DFD),as a special kind of data,is a design artifact in both requirement analysis and structured analysis in software development.However,rigorous analysis of DFD requires a formal semantics.Formal representation of DFD and its formal semantics will help to reduce inconsistencies and confusion.The logical structure of DFD can be described using formalism of Calculus of Communicating System(CCS).With a finite number of states based on CCS,state space methods will help a lot in analysis and verification of the behavior of the systems.But the number of states of even a relatively small system is often very great that is called state explosion.In this paper,we present a visual system which combines Formal methods and visualization techniques so as to help the researchers to understand and analyze the system described by the DFD regardless of the problem of state explosion.

基于开关流图法的Buck-Boost变换器小信号建模分析

阐述Buck-Boost变换器具有输出纹波低,电压可控等优点,广泛应用于新能源汽车电池发电、直流微电网。建立小信号模型有利于对电路系统主电路的控制和控制回路的设计。分析Buck-Boost变换器,利用开关流图法和信号支路的模型建立变换器的流图,从而推导出变换器的小型号模型。

基于CRCLA的形式化描述与退火遗传映射算法

为解决密码算法映射到粗粒度可重构密码逻辑阵列(CRCLA)过程的描述困难问题,提出一种数据流图节点与划分后节点簇的描述形式,并以一种坐标序列描述形式精确显示CRCLA中资源的占用情况;针对密码算法映射到CRCLA上性能不高及编译时间过长的问题,提出一种能快速收敛到全局最优解的退火遗传算法,从初始温度、降温系数等方面对退火算法进行改进,增加遗传算法的筛选、交叉与变异流程。实验结果表明,编译时间与性能平均降低了30.6%与13.4%,验证了算法的高能效映射。

中国能源系统能流、㶲流与能效分析

能源领域贡献了中国近90%的碳排放,对能源系统能流与能效的多维刻画及分析对碳中和路径的顶层设计具有极其重要的作用。能量具有“数量”与“品质”的双重属性,将能量的数量分析法和品质分析法相结合,分别从热力学第一定律能流和热力学第二定律㶲流的视角,研究并刻画了2010年和2020年中国能源系统的能流图和㶲流图。并从能源生产、加工、转换、消费等角度,对比分析了中国能源系统能源各链条能流、能效与损失的特征。发现2010年和2020年中国终端能源效率从74.52%提升至79.04%,同时能源结构向绿色低碳转型。但同期中国能源系统的㶲效率仅分别为17.44%和23.91%,能源转换的㶲损失仍较大,存在大量的电能低质利用、热能不匹配利用、能源原料燃烧利用等过程。最后,就双碳目标下中国能源效率从能流视角走向㶲流视角的提出了相关建议。

电网潮流图T接点及线路自动生成研究与应用

为了解决110 kV电网中存在大量T接线路,而潮流图中无法展示T接线路从而给电网实时监控造成很大困难的问题,提出一种电网潮流图中T接站及其线路的辅助生成方法,分析T接间隔下的线路连接关系,在常规厂站联络线布局的基础上,叠加生成T接点及其联络线。研究结果表明,该方法稳定可靠,在多个地级电网调度中心得到了实际应用。

船舶交通流速度离散特性研究

为更深刻地理解船舶交通流运行特性,以速度离散度研究为切入点,提出描述船舶交通流速度离散特性的两种指标,根据交通流基本图理论,对速度离散度在船舶交通流基本图上的分布及其与船舶交通流三参数之间的关系进行定量分析。结果表明:随着船舶流量、密度和速度的增加,速度离散度的分布趋于稳定,在低流量、高速度离散度区间内,速度离散度随着船舶流量的增加逐渐降低,在低速度离散度区间内,速度离散度随着船舶流量增加逐渐升高;基于改进的K-means-FCM算法,使用船舶交通流流量、密度、速度和速度离散度作为分类指标,对船舶交通流进行聚类分析,得到4个聚类中心与指标值的分布范围。基于试验结果,抽象总结船舶交通流运行状态图,将船舶交通流划分自由态、同质态、稳定态和异质态等4种状态。该研究对更好地认识船舶交通流特性起到一定的作用。

基于能流和碳流的文成县低碳发展路径研究

针对我国各地开展精细化碳流分析的需求,提出了一种符合我国能源结构、能够快速精细分析的能源电力分析模型和碳分析模型,并提出了相应的构建计算方法,实现了对煤炭、石油、天然气等化石能源和光伏、风电、核电等清洁发电的全覆盖。以文成县为典型案例,基于能流和碳流模型,依据能源供给、能源传输、能源消费等数据信息分析了文成县的能源系统,并从碳排放总量、碳排放结构、碳排放强度和碳排放趋势方面构建文成县全域的碳排放流。通过量化能源传输和消费过程中的碳流情况,直观展现文成县能源结构和碳排情况,并提出了文成县未来低碳发展路径。分析结果表明,文成县处于“负碳”状态,产业碳排放承载空间和终端电力替换空间巨大,亟待建立配套机制,发挥碳资产资源优势。实际案例证明了能流和碳流模型能够快速完成地区能流碳流的精细化分析,有力支撑地方双碳规划。

基于客流匹配的城市轨道交通列车运行图优化研究

列车运行图与客流需求息息相关,当运行图提供的能力与客流需求相匹配时,城市轨道交通系统既可以充分地适应乘客的需要,还可以最大限度地利用自身的运输能力。通过对乘客出行路径选择影响要素的探讨分析,改进有效路径搜索算法,构建客流分配模型并利用MSA算法对模型进行求解。基于配流结果提出列车运行图能力与客流需求匹配程度的定量评价方法,利用多目标合成的方法进行计算。基于能力匹配度的计算结果,采取相应的分时段、分区段、分方向的优化方法,实现列车运行图能力与客流需求的协调匹配。最后以南京轨道交通为例进行实例计算,与能力匹配度进行对比,结果表明:本文采取的优化方法能够使城市轨道交通列车运行图与客流需求匹配度提高19.59%。

网联进口道考虑信号影响混合基本图研究

为研究含网联自动驾驶、自动驾驶和人工驾驶车辆的混合交通流在交叉口进口道受信号影响的混合基本图变化情况,构筑信号影响下的混合交通流跟驰模型,并进行混合基本图数值仿真。结果表明,同质交通流下CAV和AV能增加进口道最大通行能力,为12.47%和4.99%;信号信息能一定程度影响交叉口进口道通行能力;增加渗透率P能够提高混合交通流于交叉口进口道通行能力,当混合交通流为最佳密度时,渗透率为0.9、0.5,相较于0.1,进口道通行能力分别提高10.71%和6.52%。

基于DFT-MARTE模型的时序分析算法

针对航天嵌入式软件(aerospace embedded software,AES)时序需求复杂带来的时序需求定义不准确问题,提出一种基于MARTE(modeling and analysis of real-time and embedded systems)模型的数据流时序(data flow timing based on MARTE,DFT-MARTE)模型,设计基于该模型的处理点缓存计算算法、时序偏离概率检测算法和时序序列分析算法。处理点缓存计算算法动态更新缓存空间,使后续时序检测正常执行;时序偏离概率检测算法利用多线程并发模拟时序特性,检测需求中时序偏离问题;时序序列分析算法是基于梯度下降算法,拟合时序序列,指导用户优化需求。该模型相比传统数据流模型更适用航天嵌入式软件,利于后续开发和维护,具有极高的应用价值。

基于三维宏观基本图的城市机非混行交通研究

为解决城市交通中机动车与非机动车混合行驶造成的交通拥堵,提出一种三维宏观基本图的理论分析方法,探究机动车与非机动车混行交通流的微观运行特征和宏观演化规律,揭示在非机动车干扰下交通拥堵的形成、传播和消散机理。先分别建立描述非机动车流的元胞自动机模型和机动车流的元胞传输模型,并借助非机动车越线次数函数将两个模型耦合;然后,在Simulink仿真平台上,运行该耦合模型以求得路网的三维宏观基本图,并以此分析非机动车驶入流量与路网平均流量、冲突次数三者间的相互关系;最后,提出提高路网硬隔离占比和加大非机动车道宽度的两种方法,借助三维宏观基本图来验证其缓解交通拥堵的效果。研究结果表明:三维宏观基本图的分析方法可量化机动车和非机动车冲突的影响,指导混行交通拥堵的治理,该结论为改善中国城市交通出行秩序和出行环境提供了参考。

核电厂智能化DCS数据管理系统建设

本文针对福清核电DCS系统,因不同平台的技术差异,图纸、组态和接口数据量大,文件复杂,使用和管理过程效率低下,人因风险高。基于此,提出了一种以面向内容为核心,以计算机数据库技术为基本方法,依托设计输入文件和运行过程数据,构建要素间普遍联系的DCS数据管理系统。有效梳理了相关业务所需要的各类数据和文件的获取与处理方式,实现数据组织、图纸与组态数据的精确关联,并设计和建设了一站式检索平台,对数据和图纸进行深度分析,实现自动化风险提示的变更管理,以服务于现场执行控制系统相关工作和检查的各个过程。本文详细论述了需求分析和项目建设办法,为类似项目的建设、维护提供经验。

花式彩灯PLC控制程序设计与解析

给出花式彩灯显示PLC控制要求,采用模式开关设定显示模式,利用数据传送指令对M寄存器进行初始化赋值,并通过移位指令实现彩灯显示状态的动态变换、启停按钮启动和停止显示状态。

Anisotropic flow in high baryon density region

Collective flow is a powerful tool used to analyze the properties of a medium created during high-energy nuclear collisions.Here,we report a systematic study of the first two Fourier coefficients v_(1)and v_(2)of the proton andπ^(+)from Au+Au collisions in the energy range√sNN=2.11-4.9 GeV within the framework of a hadronic transport model(UrQMD).Recent results from the STAR experiment were used to test the model calculations.A meanfield mode with strong repulsive interaction is needed to reproduce the 10-40%data at 3 GeV.This implies that hadronic interactions play an important role in the collective flow development in the high baryon density region.The mean values of the freeze-out time for protons andπ^(+)are shifted earlier owing to the additional repulsive interactions.We predict the energy dependence of the mean values of the transverse momentum<pT>,v_(1),and v_(2)for both protons andπ^(+)from the Au+Au collisions.

Analysis of interrelationship between pedestrian flow parameters using artificial neural network

Pedestrian flow parameters are analysed in this study considering linear and non-linear relationships between stream flow parameters using conventional and soft computing approach. Speed-density relationship serves as a fundamental relationship, Single-regime con- cepts and deterministic models like Greenshield and Underwood were applied in the study to describe bidirec- tional flow characteristics on sidewalks and carriageways around transport terminals in India. Artificial Neural Net- work （ANN） approach is also used for traffic flow mod- elling to build a relationship between different pedestrian flow parameters. A non-linear model based on ANN is suggested and compared with the other deterministic models. Out of the aforesaid models, ANN model demonstrated good results based on accuracy measure- ment. Also these ANN models have an advantage in terms of their self-processing and intelligent behaviour. Flow parameters are estimated by ANN model using MFD （Macroscopic Fundamental Diagram）. Estimated mean absolute error （MAE） and root mean square error （RMSE）values for the best fitted ANN model are 3.83 and 4.73 m/ min, respectively, less than those for the other models for sidewalk movement. Further estimated MAE and RMSE values of ANN model for carriageway movement are 4.02 and 4.98 m/min, respectively, which are comparatively less than those of the other models. ANN model gives better performance in fitness of model and future prediction of flow parameters. Also when using linear regression model between observed and estimated values for speed and flow parameters, performance of ANN model gives better fitness to predict data as compared to deterministic model. R value for speed data prediction is 0.756 and for flow data pre- diction is 0.997 using ANN model at sidewalk movement around transport terminal.

Application and comparison of coaxial correlation diagram and hydrological model for reconstructing flood series under human disturbance

Intense human activities have greatly changed the flood generation conditions in most areas of the world, and have destroyed the consistency in the annual flood peak and volume series. For design flood estimation, coaxial correlation diagram and conceptual hydrological model are two frequently used tools to adjust and reconstruct the flood series under human disturbance. This study took a typical mountain catchment of the Haihe River Basin as an example to investigate the effects of human activities on flood regime and to compare and assess the two adjustment methods. The main purpose is to construct a conceptual hydrological model which can incorporate the effects of human activities. The results show that the coaxial correlation diagram is simple and widely-used, but can only adjust the time series of total flood volumes. Therefore, it is only applicable under certain conditions(e.g. There is a strong link between the flood peaks and volumes and the link is not significantly affected by human activities). The conceptual model is a powerful tool to adjust the time series of both flood peak flows and flood volumes over different durations provided that it is closely related to the catchment hydrological characteristics, specifically accounting for the effects of human activities, and incorporating expert knowledge when estimating or calibrating parameters. It is suggested that the two methods should be used together to cross check each other.

Study of shear-thinning/thickening effects on plane Couette-Poiseuille flow with uniform crossflow

The shear-thinning/thickening effects on the plane Couette-Poiseuille flow with a uniform crossflow are studied. The detailed solution procedures for both theo- retical and numerical purposes are given. In order to clarify the difference between the Newtonian flow and the power-law flow, all cases of the plane Couette-Poiseuille flows with uniform crossflows for different power indexes are assigned to the phase diagram in the parameter plane corresponding to the Couette number and the crossflow Reynolds number. The effects of shear-thinning/thickening on the phase diagram are discussed. An important feature of the shear-thinning circumstance distinguished from the shear- thickening circumstance is discovered.