Counting statistics and decoherence in coupled quantum dots
史上最全的因果识别经典前沿书籍,仅此一份
史上最全的因果识别经典前沿书籍,仅此⼀份Copyrights @计量经济圈(ID:econometrics666), 社群推荐。
近年来,在微观计量领域,因果识别策略已经占据了主流,传统的⽅法始终难以解决关于内⽣性问题的难题。
计量经济圈的核⼼优势就是因果识别,传统的宏观领域的多⽅程关系研究也在吸收因果识别策略。
在不久的将来,因果识别领域会有⼏位先锋者得到诺贝尔经济学奖。
如果你对这些前沿技术也感兴趣,那可以加⼊咱们⼤社群⼀起切磋交流学习(见⽂末)。
Confounding in CausalInferenceWei PanCausality andModern Science: Third Revised EditionMario BungeAn Introductionto Causal InferenceJudea PearlCausality:Statistical Perspectives and ApplicationsCarlo BerzuiniProbability: For the Enthusiastic BeginnerDavid MorinMastering 'Metrics: The Path from Causeto Effect- Joshua David AngristCounterfactuals and Causal Inference:Methods and… -Stephen L. MorganCausal Inference in Statistics: A PrimerJudea PearlCausalityJudea PearlCausal Inference for Statistics, Social, and Biome…- Guido W. ImbensConfounding in Causal Inference2010-04Wei PanCausalInferences and Abductive Reasoning2009-03Chong Ho YuCausal Inferencein Econometrics2016-01Van-Nam Huynh、 Vladik KreinovichStatisticalCausal Inferences and Their Applications in Public Health Research 2016-11Hua He、 Pan WuTargetedLearning: Causal Inference for Observational and Experimental Data2013-08Mark J. van derLaan、 Sherri RoseThe SAGEHandbook of Regression Analysis and Causal Inference2014-10Henning Best、 Christof WolfStatisticalModels and Causal Inference: A Dialogue with the Social Sciences2009-11David A.Freedman、 David CollierApplied BayesianModeling and Causal Inference from Incomplete-Data Perspectives 2004-09Andrew Gelman、 Xiao-Li MengCase Studies andCausal Inference: An Integrative Framework2012-09I. RohlfingThe Role ofCausal Models in Inductive Inference Based on Categories2011-09Xinzhi Chen、 Hee Seung LeeMaking itFormally Explicit: Probability, Causality and Indeterminism2017-05GáborHofer-Szabó、 Leszek WrońskiCausality:Philosophical Theory meets Scientific Practice2014-10Phyllis Illari、 Federica RussoCausality2013-06Frederic PMiller、 Vandome Agnes FCausality2015-08Guanglei HongCausality:Objectives and Assessment: Challenges in Machine Learning, Volume 4 2012-11Isabelle Guyon、 Dominik JanzingCausality, Or,the Philosophy of Law Investigated2016-05George JamiesonFinancial Crisesand Earnings Management Behavior: Arguments and Evidence Against Causality2017-09Bruno Maria FranceschettiEvidence,Decision and Causality2017-02Arif AhmedCausality,Meaningful Complexity and Embodied Cognition2012-05A. CarsettiCausality, Correlationand Artificial Intelligence for Rational Decision Making2015-02TshilidziMarwalaCausality inSociological Research2011-09Jakub KarpinskiCausality andProbability in the Sciences: v. 52007-01Dr. FedericaRusso、 Jon WilliamsonTime SeriesModels, Causality and Exogeneity1997-06Omar F. Hamouda、 J. C. R. RowleyStochastic Causality2001-12Maria CarlaGalavotti、 Patrick SuppesCausality andCausal Modelling in the Social Sciences: Measuring Variations2008-10Federica RussoBayesianNetworks and GIS Techniques for Modelling Land Degradation2009-08Oumer AhmedCausality in Macroeconomics2001-08Kevin D. HooverMechanism and Causalityin Biology and EconomicsSpace, Time andCausality: An Essay in Natural Philosophy1985-03J. R. LucasComplexSocio-Technical Systems: Understanding and Influencing the Causality of Change 2012-07W. B. Rouse、K.R. Boff、 P. SandersonCausality; thePlace of the Causal Principle in Modern Science1959by MarioAugusto BungeUncertainty andcausality in practical inference1981by Hillel JEinhorn名称Three Essays on Causality Approach to Modeling Long-term Economic Growth 作者Piyachart Phiromswad撰稿⼈University of California, DavisCausal Inference and ScientificParadigms in EpidemiologySteven S. Coughlin - 2010 -Causal inferenceK. J. Rothman -1988 -Causal inference for multi-levelobservational data with application ...Guanglei Hong - 2004 -Case Studies and Causal Inference: AnIntegrative FrameworkI. Rohlfing - 2012 -This frameworkis applied to research design tasks such as case selection and process tracing.The book presents the basics, state-of-the-art and arguments for improving thecase study method and empirical small-n research.From Predictive to Causal Inference: TheUse of Multivariate ...2014 -The time seriesof covariance that multivariate GARCH models generate, however, holdprofoundpromise for informing pre-existing causal inferential debate throughout thesocial sciences. A research methodology framework is needed.Complete Identification Methods forCausal InferenceIlya Shpitser - 2008 -Using theframework of graphical causal models which formalizes a variety of causalqueries, such as causal effects, counterfactuals and path-specific effects ascertain types of probability distributions, I will develop algorithms which ...Causal Inference in EconometricsVan-Nam Huynh,V ladik Kreinovich, S ongsak Sriboonchitta - 2015 -This book isdevoted to the analysis of causal inference which is one of the most difficulttasks in data analysis: when two phenomena are observed to be related, it isoften difficult to decide whether one of them causally influences the ...Explanation in Causal Inference: Methodsfor Mediation and InteractionTyler VanderWeele - 2015 -and approachesto mediation and interaction from the causal inference literature employingcounterfactuals. This counterfactual approach can be extended to addressquestions of mediation and interaction by extending the counterfactual ...A Review of Causal InferenceDayang Liu - 2009 -Abstract: Inthis report, I first review the evolution of ideas of causation as it relatesto causal inference.Applied Bayesian modeling and causalinference from incomplete-data ...Donald B. Rubin, A ndrewGelman, X iao-Li Meng - 2004 -This book bringstogether a collection of articles on statistical methods relating to missingdata analysis, including multiple imputation, propensity scores, instrumentalvariables, and Bayesian inference.Causality: Models, Reasoning, andInferenceJudea Pearl - 2000 -The book willfacilitate the incorporation of causal analysis as an integral part of thestandard curriculum in statistics, business, epidemiology, social science andeconomics.Causal Inference Methods for EstimatingLong-term Health Effects of ...Corwin Matthew Zigler - 2016 -Parametric Potential-outcome SurvivalModels for Causal Inference: A ...Zhaojing Gong - 2008 -Causal Inference, Path Analysis andRecursive Structural Equations ...1988 -Restricted Structural Equation Modelsfor Causal InferenceJonas Martin Peters - 2012 -Essays in Causal Inference and PublicPolicyAvi Isaac Feller - 2015 -Thisdissertation addresses statistical methods for understanding treatment effectvariation in randomized experiments, both in terms of variation acrosspre-treatment covariates and variation across post-randomization intermediateoutcomes ...Causal Inference in Urban and RegionalEconomicsNathaniel Baum-Snow, F ernando Ferreira - 2014 -Recovery ofcausal relationships in data is an essential part of scholarly inquiry in thesocial sciences.Statistics and Causality: Methods forApplied Empirical Research WolfgangWiedermann, A lexander von Eye - 2016 -The book isdivided into five accessible and independent parts. The first part introducesthe foundations of causal structures and discusses issues associated withstandard mechanistic and difference-making theories of causality.Latent Variable Modeling and Applicationsto CausalityMaia Berkane - 2012-The papers inthis volume are representative of a wide variety of disciplines in which theuse of latent variable models is rapidly growing. The volume is divided intotwo broad sections.The Oxford Handbook of Causal ReasoningMichael Waldmann -2017 -Causal Analysis in Population Studies:Concepts, Methods, Applications HenrietteEngelhardt, H ans-Peter Kohler, A lexia Fürnkranz-Prskawetz - 2010 -This bookpresents both theoretical contributions and empirical applications of thecounterfactual approach to causal inference.Foundations of BayesianismD. Corfield, J onWilliamson - 2013 -This is anauthoritative collection of papers addressing the key challenges that face theBayesian interpretation of probability today.Multilevel Modeling of Social Problems:A Causal PerspectiveRobert B Smith - 2014 -Uniquelyfocusing on intersections of social problems, multilevel statistical modeling,and causality; the substantively and methodologically integrated chapters ofthis book clarify basic strategies for developing and testing multilevel ...Why: A Guide to Finding and Using CausesSamantha Kleinberg - 2015 -This book helpsyou think about causality in a structured way: What is a cause, what are causesgood for, and what is compelling evidence of causality?Causality: A Study of SeventeenthCentury PhilosophyDaisie Radner - 1969 -Theories of Causality: From Antiquity tothe PresentJohn Losee - 2012 -This volume is awide-ranging history of answers that have been given to these threequestions,and their relationship to scientific understanding.Causality and ExplanationWesley C. Salmon - 1998 -This uniquevolume brings together twenty-six of his essays on subjects related tocausality and explanation, written over the period 1971-1995.A probabilistic theory of causalityPatrick Suppes - 1970 -Capturing Connectivity and Causality inComplex Industrial ProcessesFan Yang, P ing Duan, S irish L. Shah - 2014 -In this chapter,we focus on the relationship between different time series to capturecausality in the process. For a pair ofprocess variables, various data-based methods can be applied to detect causality. These methods can becategorized ..Causality and ScienceNalini Kanta Brahma - 2008 - ⽆预览 -The writing ofthis book has afforded him pleasure in his leisure moments, and that pleasurewould be much increased if he knew that the perusal of it would create any bondof sympathy between himself and the angling community in general.The perception of causalityAlbert Michotte -1963 - 阅读内容摘录 -Correlation and causalityDavid A. Kenny - 1979 -Structuralmodeling; Covariance algebra; Principles of path analysis; Models with observedvariables as causes; Measurement error in the exogenous variable and thirdvariables; Observed variables as causes of each other; Single unmeasured ...Causality in natural scienceVictor Fritz Lenzen - 1954 - 阅读内容摘录 -Causal Overdetermination andContextualismEsteban Céspedes - 2016 -This workexplains how different theories of causation confront causal overdetermination.Causal Reasoning: A Systems ApproachJohn Charles Francis - 1992 -Synthesizes thecausal reasoning used in artificial intelligence, and the traditional expert systemapproaches based on heuristic knowledge, thus providing a methodology foranalyzing causal mechanisms in physical systems.Causation & Causality: Two Mirrorsof the CauseS. K. Leung - 2002 -With DavidHume's profound philosophical doubts on causation at the background, this bookattempts to answer many difficult questions.Visualizing Causality in Context UsingAnimation2007 -Keywords:visualization of causality, perception of causality, causal overlay, visualcausal vector。
港大数据科学笔试题目
港大数据科学笔试题目
港大数据科学笔试题目可能涉及多个领域,包括统计学、计算机科学、数学等。
以下是一些可能的笔试题目示例:
1. 统计学基础:如何计算平均数、中位数、众数?解释它们的意义和应用。
2. 概率论与数理统计:什么是随机变量?列举几个常见的随机变量类型。
解释期望值和方差的定义和计算方法。
3. 线性代数:什么是矩阵的逆矩阵和行列式?如何计算矩阵的乘积?
4. 数据分析:如何处理缺失数据和异常值?描述几种常见的数据可视化技术。
5. 数据挖掘:什么是聚类分析?它有哪些应用场景?
6. Python编程:编写一个Python程序来读取一个CSV文件,并计算每列的平均值。
7. SQL查询:编写一个SQL查询来检索某个表中所有不重复的记录。
8. 机器学习:解释支持向量机(SVM)和随机森林算法的基本原理。
这只是一部分可能的笔试题目示例,具体的题目会根据招聘岗位的要求和考试大纲而有所不同。
如果你想准备港大数据科学相关的笔试,建议提前了解相关课程和知识点,并熟悉相关编程语言和技术。
fassis 相似计算 大规模计算
fassis 相似计算大规模计算大规模计算是指通过对大量数据进行处理和分析,以获取有用信息的一种计算方式。
随着互联网和信息技术的发展,大规模计算正在成为各个领域的重要工具。
在这篇文章中,我们将以fassis相似计算为切入点,探讨大规模计算的应用和意义。
让我们来了解一下fassis相似计算。
fassis相似计算是一种基于图像和视频内容的计算方法,通过对图像和视频进行特征提取和匹配,来判断它们之间的相似度。
这种计算方式可以广泛应用于图像搜索、视频监控、人脸识别等领域。
在大规模计算中,fassis相似计算起到了重要的作用。
大规模计算的应用非常广泛。
在金融领域,大规模计算可以用来进行风险评估和投资决策。
通过对大量的金融数据进行分析和计算,可以快速准确地评估风险,并提供决策支持。
在医疗领域,大规模计算可以用来进行疾病诊断和治疗方案设计。
通过对大规模的医学数据进行分析和计算,可以帮助医生更好地理解疾病的发展规律,提供更准确的诊断和治疗方案。
在交通领域,大规模计算可以用来进行交通流量预测和交通优化。
通过对大量的交通数据进行分析和计算,可以帮助交通管理部门更好地规划路网,提高交通效率。
在电商领域,大规模计算可以用来进行用户行为分析和个性化推荐。
通过对大量的用户数据进行分析和计算,可以帮助电商平台更好地理解用户需求,提供更精准的推荐服务。
大规模计算的意义在于它可以帮助我们更好地理解和利用大数据。
随着互联网和物联网技术的发展,我们正处在一个数据爆炸的时代,每天都会产生大量的数据。
这些数据蕴含着重要的信息,但如果不经过计算和分析,这些信息将无法被发现和利用。
大规模计算通过对大数据进行处理和分析,可以帮助我们从海量的数据中提取有用的信息,为决策和创新提供支持。
同时,大规模计算还可以帮助我们发现数据之间的关联和规律,从而更好地理解和解决实际问题。
然而,大规模计算也面临着一些挑战和问题。
首先,由于数据量庞大,大规模计算需要强大的计算资源和高效的算法。
多元时间序列数据熵特征提取
多元时间序列数据熵特征提取
随着数据采集和存储技术的不断发展,我们所面对的数据越来越多样化和多元化。
在时间序列数据分析中,如何从这些多元时间序列数据中提取有效的特征,成为了一个重要而复杂的问题。
熵是一种常用的特征提取方法,通过对数据的分布情况进行度量,可以反映数据的不确定性和复杂性。
对于单一时间序列数据,熵的计算比较简单,但对于多元时间序列数据,由于数据之间的耦合关系,熵的计算会更加困难。
近年来,研究者们提出了许多基于熵的多元时间序列数据特征提取方法,包括联合熵、条件熵、互信息等。
这些方法不仅考虑了数据的单一特性,还考虑了数据之间的相互作用和影响,可以更全面地反映数据的特征和规律。
在实际应用中,多元时间序列数据熵特征提取可以应用于各种领域,如金融数据分析、医疗诊断、环境监测等。
通过对数据的深入分析和特征提取,可以更好地理解数据的本质和规律,为实际问题的解决提供有力的支撑。
- 1 -。
时间序列相似性查询的研究与应用
时间序列相似性查询的研究与应用随着大数据时代的到来,时间序列数据的重要性逐渐凸显。
时间序列数据是指按照时间顺序排列的一组数据,例如股票价格、气温变化、心电图等。
时间序列相似性查询作为一种重要的数据分析技术,旨在寻找与查询样本相似的时间序列数据,从而揭示隐藏在数据背后的规律和趋势。
在各个领域的实际应用中,时间序列相似性查询已经发挥了重要的作用。
时间序列相似性查询的研究主要包括两个方面:相似性度量和相似性查询算法。
相似性度量是衡量两个时间序列数据之间相似程度的方法,常用的度量方法包括欧氏距离、曼哈顿距离、动态时间规整等。
相似性查询算法是根据相似性度量方法,对大规模时间序列数据进行高效查询的方法,常用的算法包括基于索引的查询、基于哈希的查询、基于树结构的查询等。
这些研究成果为时间序列数据的分析和挖掘提供了基础。
时间序列相似性查询在实际应用中具有广泛的应用前景。
首先,在金融领域,通过对历史股票价格的相似性查询,可以预测未来股票价格的走势,为投资者提供决策依据。
其次,在气象领域,通过对历史气温变化的相似性查询,可以预测未来天气的变化,为气象预报提供支持。
再次,在医疗领域,通过对心电图的相似性查询,可以诊断心脏疾病,为医生提供治疗方案。
另外,在工业生产领域,通过对传感器数据的相似性查询,可以提前预测设备故障,进行维护和修复,提高生产效率。
然而,时间序列相似性查询也面临一些挑战。
首先,大规模时间序列数据的查询效率是一个问题,传统的查询算法无法满足实时查询的需求。
其次,相似性度量方法的选择也是一个难题,不同领域的数据可能需要采用不同的度量方法。
此外,在多维时间序列数据的查询中,如何考虑多个维度之间的相似性也是一个研究方向。
总之,时间序列相似性查询作为一种重要的数据分析技术,在各个领域的实际应用中发挥了重要作用。
未来,我们需要进一步研究相似性度量方法和查询算法,提高查询效率和准确性,以更好地应对大数据时代的挑战。
数据仓库与数据挖掘教程(第2版)课后习题答案第七章
数据仓库与数据挖掘教程(第2版)课后习题答案第七章第七章作业1.信息论的基本原理是什么?一个传递信息的系统是由发送端(信源)和接收端(信宿)以及连接两者的通道(信道)组成的。
信息论把通信过程看做是在随机干扰的环境中传递信息的过程。
在这个通信模型中,信息源和干扰(噪声)都被理解为某种随机过程或随机序列。
在进行实际的通信之前,收信者(信宿)不可能确切了解信源究竟会发出什么样的具体信息,也不可能判断信源会处于什么样的状态。
这种情形就称为信宿对于信源状态具有不确定性,而且这种不确定性是存在于通信之前的,因而又叫做先验不确定性。
在通信后,信宿收到了信源发来的信息,这种先验不确定性才会被消除或者被减少。
如果干扰很小,不会对传递的信息产生任何可察觉的影响,信源发出的信息能够被信宿全部收到,在这种情况下,信宿的先验不确定性就会被完全消除。
但是,在一般情况下,干扰总会对信源发出的信息造成某种破坏,使信宿收到的信息不完全。
因此,先验不确定性不能全部被消除, 只能部分地消除。
换句话说,通信结束之后,信宿仍具有一定程度的不确定性。
这就是后验不确定性。
2.学习信道模型是什么?学习信道模型是信息模型应用于机器学习和数据挖掘的具体化。
学习信道模型的信源是实体的类别,采用简单“是”、“非”两类,令实体类别U 的值域为{u1,u2},U 取u1表示取“是”类中任一例子,取u2表示取“非”类中任一例子。
信宿是实体的特征(属性)取值。
实体中某个特征属性V ,他的值域为{v1,v2……vq}。
3.为什么机器学习和数据挖掘的分类问题可以利用信息论原理?信息论原理是数据挖掘的理论基础之一。
一般用于分类问题,即从大量数据中获取分类知识。
具体来说,就是在已知各实例的类别的数据中,找出确定类别的关键的条件属性。
求关键属性的方法,即先计算各条件属性的信息量,再从中选出信息量最大的属性,信息量的计算是利用信息论原理中的公式。
4自信息:单个消息ui 发出前的不确定性(随机性)称为自信息。
武汉大学资环学院gis地图学与地理信息系统考研(真题+答案+笔记)
现在大家可能也在面临着选择,比如是否考研,考哪个学校,考哪个专业,跟哪个导师, 怎样平衡专业课与公共课的时间等等。作为过来人,当初的我们和大家一样,也在思考着类 似的问题;也正因为是过来人,我们才有了给大家提供建议的底气。借此机会,把我们一些 个人看法与大家交流,虽个人经历不同,经验不足以证明什么,但仅供参考之用足矣! 1、为什么要考研?
II
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数据通信原理实验指导书
实验一编码与译码一、实验学时:2学时二、实验类型:验证型三、实验仪器:安装Matlab软件的PC机一台四、实验目的:用MA TLAB仿真技术实现信源编译码、差错控制编译码,并计算误码率。
在这个实验中我们将观察到二进制信息是如何进行编码的。
我们将主要了解:1.目前用于数字通信的基带码型2.差错控制编译码五、实验内容:1.常用基带码型(1)使用MATLAB 函数wave_gen 来产生代表二进制序列的波形,函数wave_gen 的格式是:wave_gen(二进制码元,…码型‟,Rb)此处Rb 是二进制码元速率,单位为比特/秒(bps)。
产生如下的二进制序列:>> b = [1 0 1 0 1 1];使用Rb=1000bps 的单极性不归零码产生代表b的波形且显示波形x,填写图1-1:>> x = wave_gen(b,…unipolar_nrz‟,1000);>> waveplot(x)(2)用如下码型重复步骤(1)(提示:可以键入“help wave_gen”来获取帮助),并做出相应的记录:a 双极性不归零码b 单极性归零码c 双极性归零码d 曼彻斯特码(manchester)x 10-3x 10-3x 10-3x 10-32.差错控制编译码(1) 使用MATLAB 函数encode 来对二进制序列进行差错控制编码, 函数encode 的格式是:A .code = encode(msg,n,k,'linear/fmt',genmat)B .code = encode(msg,n,k,'cyclic/fmt',genpoly)C .code = encode(msg,n,k,'hamming/fmt',prim_poly)其中A .用于产生线性分组码,B .用于产生循环码,C .用于产生hamming 码,msgx 10-3图1-5曼彻斯特码图1-1 单极性不归零码 图1-3单极性归零码 图1-4双极性归零码图1-2双极性不归零码为待编码二进制序列,n为码字长度,k为分组msg长度,genmat为生成矩阵,维数为k*n,genpoly为生成多项式,缺省情况下为cyclpoly(n,k)。
逻辑斯蒂回归的损失函数求和项数与训练样本数相同
逻辑斯蒂回归的损失函数求和项数与训练样本数相同逻辑斯蒂回归(Logistic Regression)是一种二分类算法,其目的是在给定输入特征的情况下,预测输出为1或0的概率。
在训练阶段,我们通过最小化损失函数来学习模型参数。
而这个损失函数通常被称为交叉熵损失函数。
交叉熵损失函数是用来评估模型预测结果与真实结果之间差距的一种方法。
对于逻辑斯蒂回归来说,它的目标是最小化错误率或误差概率。
因此,我们需要将交叉熵损失函数定义为:$$J(\theta)=-\frac{1}{m}\sum_{i=1}^{m}[y^{(i)}log(h_{\theta}(x^{(i)}))+(1-y^{(i)})log(1-h_{\theta}(x^{(i)}))]$$其中$J(\theta)$表示损失函数,$\theta$表示模型参数,$m$表示训练样本数,$y^{(i)}$表示第$i$个样本的真实标签值(0或1),$h_{\theta}(x^{(i)})$表示对第$i$个样本预测为1的概率值。
从式子可以看出,逻辑斯蒂回归的损失函数求和项数与训练样本数相同。
这是因为每个样本都会对损失函数产生一定的贡献,而我们需要将所有样本的贡献加起来,以得到最终的损失函数值。
具体来说,对于每个样本,我们都要计算其预测值与真实值之间的差距,并将其累加到总损失函数中。
如果预测值与真实值相同,则差距为0;否则,差距越大,则损失函数越大。
通过最小化总损失函数,我们可以优化模型参数,使其能够更好地拟合训练数据。
需要注意的是,在逻辑斯蒂回归中,我们使用了sigmoid函数来将线性回归模型的输出转换为概率值。
这个转换过程可以表示为:$$h_{\theta}(x)=\frac{1}{1+e^{-\theta^{T}x}}$$其中$\theta^{T}x$表示线性回归模型的输出结果。
通过将其带入sigmoid函数中,我们可以得到一个介于0和1之间的概率值。
如果概率大于等于0.5,则预测结果为1;否则,预测结果为0。
频繁项集和关联规则的计算
频繁项集和关联规则的计算(最新版)目录1.频繁项集的计算2.关联规则的计算3.应用实例正文在数据挖掘领域,频繁项集和关联规则的计算是挖掘关联规则的两个关键步骤。
频繁项集是指在数据集中出现频率达到一定阈值的项集,而关联规则则是指数据集中各个项之间的关系。
通过计算频繁项集和关联规则,我们可以发现数据集中有价值的信息,从而为决策提供依据。
下面我们将详细介绍频繁项集和关联规则的计算方法以及一个应用实例。
一、频繁项集的计算频繁项集是指在数据集中出现频率达到一定阈值的项集。
为了计算频繁项集,我们需要先定义一个支持度阈值,即满足该阈值的项集被称为频繁项集。
计算频繁项集的主要方法有 Apriori 算法和 FP-growth 算法。
1.Apriori 算法Apriori 算法是一种生成候选项集的方法,然后根据支持度阈值筛选出频繁项集。
算法的基本思想是:首先从单个项开始,逐步扩展项集,生成所有可能的项集;然后根据数据集中的统计信息,计算每个项集的支持度,筛选出支持度大于阈值的频繁项集。
2.FP-growth 算法FP-growth 算法是 Apriori 算法的改进算法,主要优点是减少了计算次数,提高了计算效率。
FP-growth 算法的基本思想是:根据数据集中的项频率信息,生成一个有向无环图(FP-tree),然后根据支持度阈值,从 FP-tree 中挖掘出频繁项集。
二、关联规则的计算关联规则是指数据集中各个项之间的关系,通常用支持度、置信度和提升度来度量。
计算关联规则的主要方法有 Apriori 算法和 FP-growth 算法。
1.Apriori 算法Apriori 算法在计算频繁项集的基础上,可以进一步挖掘关联规则。
算法的基本思想是:根据频繁项集生成满足最小置信度要求的关联规则。
2.FP-growth 算法FP-growth 算法也可以用于计算关联规则。
基于 FP-tree,可以生成满足最小支持度和置信度要求的关联规则。
综保使用说明书
ABB Network PartnerRelay Configuration Tool (4)Specification for RE_ 54_ Configurations (5)Editing the RE_ 54_ Relay Terminal Configurations (6)Getting started (6)Libraries (6)Logical POUs (7)Program Organisation Unit (POU) (7)Physical hardware (9)Configuration (10)Resource (11)Hardware version (11)Analogue channels (11)Binary inputs (16)Measurements (17)Condition monitoring (18)Tasks (19)Programs and tasks (19)Task interval (19)Global variables (20)Declaring variables (21)Variables declared as global (25)Compiling the project (28)Main Configuration Rules for RE_ 54_ (29)General (29)Binary inputs (29)Explicit feedback (30)Measurement function blocks (31)Warnings (31)Execution order (32)F-key (33)APPENDIX A (35)APPENDIX B............................................................................................ 37-50 APPENDIX C............................................................................................ 51-65About this manualThis guideline describes in general the procedures for configuring the REF 54_ feeder terminals or REM 543 machine terminals correctly with the Relay Configuration Tool. Furthermore, chapter 4 provides some practical tips as well as recommendations and restrictions for doing the configuration.Please note that the examples and dialogue pictures of the Relay Configuration Tool in this manual refer to REF 54_ feeder terminals.1.Relay Configuration ToolThe Relay Configuration Tool, which is a standard programming system for RED500devices, is used for configuring the protection, control, condition monitoring, measure-ment and logic functions of the feeder terminal. The tool is based on the IEC 1131-3standard, which defines the programming language for relay terminals, and includes thefull range of IEC features. The PLC logics are programmed with Boolean functions,timers, counters, comparators and flip-flops. The programming language described inthis manual is a function block diagram (FBD) language.2.Specification for RE_ 54_ ConfigurationsPrior to starting the configuration of a relay terminal, the Specification for Relay Con-figuration is to be filled out. The specification can be found as appendix B for REF 54_and appendix C for REM 543 in the end of this manual.The purpose of the specification is to provide the technical information required for theproper configuration of the relay terminals.3.Editing the RE_ 54_ Relay Terminal Configurations 3.1.Getting startedStart up the tool by double clicking the icon. After adding a new object as an empty con-figuration to the CAP505 environment (refer to the CAP505 Operator’s Manual, 1MRS750838-RUM), the program opens an empty project template (see figure below) with atoolbar at the top. The next step is to build the project tree structure by inserting librar-ies, program organisation units (POUs) and target specific items to the project tree.The project tree editor is a window in which the whole project is represented as a tree.The project tree is illustrated with several icons. Most of the icons represent a file of theproject and different looking icons represent different types of files. The tree alwayscontains 4 subtrees: Libraries, Data Types, Logical POUs and Physical Hardware.Fig. 3.1-1. The project tree with its four subtrees.The project tree is the main tool for editing the project structure. Editing the projectstructure means inserting POUs or worksheets to the project structure or deleting exist-ing ones. The editors for editing the data of the code bodies and the variable declarationcan be called by double clicking the corresponding object icons.If you intend to edit an old project, note that saving the changes made with the “save as”project unchanged, the project has to be saved with a new name before making anychanges.3.1.1.LibrariesBefore editing any worksheets of POUs, the whole project tree structure must be build.The function block library (protection, control, measurement, condition monitoring andstandard functions) needed in the relay configuration is to be inserted to the “Libraries”subtree.Before inserting the library to the project, all worksheets are to be closed; otherwise theI/O description of function blocks will be confused. The programs, function blocks (e.g.NOC3Low, the low set stage of non-directional three-phase overcurrent protection) andfunctions of the library can be reused in the new project, which is edited.The library, e.g. REFLIB01 for REF54_ (see the figure below), includes all availablefunction blocks. Therefore, attention is to be paid to which function blocks can be usedin a specific configuration. For example, if the protection library PR116005(1MRS116005) has been ordered, the auto-reclose function block AR5Func cannot beinserted to the project since AR5Func is not included in that library.Fig. 3.1.1.-1. Libraries for REF54_ and REM 543.3.1.2.Logical POUsIn the project tree editor and in the library editor, the “Logical POUs” subtree representsa directory for all POUs related to the project. The maximum of 20 POUs can beinserted to the subtree. The figure below shows a “Logical POUs” subtree with 6 POUs;“Measure”, “Prot_Me” and “Co_CM_A” represent FBD (Function Block Diagram)programs, and “Horizon”, “CONDIS” and “SWG” are FBD function blocks.Fig. 3.1.2.-1. “Logical POUs” subtree with 6 POUs.3.1.3.Program Organisation Unit (POU)Each Program Organisation Unit, a POU, consists of several worksheets: a POUdescription worksheet for comments, a variable worksheet for variable declarations anda code body worksheet for the relay configuration. The name of each worksheet is indi-cated beside the corresponding icon and the *-symbol after the name of a worksheetindicates that the worksheet has not been compiled yet.Fig. 3.1.3.-1. Program organisation unit with three worksheets.The description worksheet (e.g. ProtectT) illustrated below is for describing the POU or the configuration element. The worksheet is named by adding a ’T’ to the name of the POU.Fig. 3.1.3.-2. Description worksheet.The variable worksheet (e.g. ProtectV) is for the variable declaration. The worksheet is named by adding a ’V’ to the name of the POU.Fig. 3.1.3.-3. Variable declaration worksheet.A code body worksheet (e.g. Protect, Measure) is for a code body declaration in theform of an FBD, a Function Block Diagram. All configurations for relays of the RED500 platform are made in the graphical FBD language. A code body programmed in theFBD language is composed of functions and function blocks that are connected to eachother using variables or lines. An output of a function block can be connected to the out-put of another function block only via an OR gate (refer to section 4.1.)Fig. 3.1.3.-4. Code body declaration in FBD language.Even though the tool permits adding several graphical worksheets under one POU, onlyone worksheet is recommended to be used per POU. If more space is needed for a con-figuration, the worksheet size can be increased or, if more I/O points are required, thefunctionality can be divided to several POUs. Note that one POU has altogether 511 I/Opoints available for function blocks. For example, the function block NOC3High in thefigure above includes 15 I/O points, which means that there are still 496 I/O pointsavailable.3.1.4.Physical hardwareIn the project tree editor, the physical hardware is represented as a subtree (see below)after the hardware of the relay terminal, i.e. Configuration, Resource and Tasks, hasbeen defined.Fig. 3.1.4.-1. Example of a subtree for the physical hardware.The configuration elements available in the “Physical Hardware” subtree may differfrom configuration to configuration. Each terminal of the RED 500 platform can beconfigured separately.3.1.4.1.ConfigurationThe name and target of the configuration are first defined in the dialogue Properties/Configuration.Fig. 3.1.4.1.-1. Defining the configuration type.3.1.4.2.ResourceThe configuration “Conf” above is for the REF 543 resource (the selected processortype), which is defined in the dialogue Properties/Resource. The resource must also begiven a name.Fig. 3.1.4.2.-1. Defining the processor type.Hardware versionAfter selecting the processor type, click “Settings...” in the dialogue Properties/Resource (see figure above) to define the correct hardware version.Note! After selecting the correct hardware version (Relay Variant; see figure below), donot click OK but wait until the next dialogue opens and select “Analog Channels” (seefigure 3.1.4.2.-3.).Fig. 3.1.4.2.-2. Defining the hardware version.Analogue channelsIn the dialogue Settings/Analog Channels, click each channel in turn to select the meas-uring device and signal type for the channels used and select “Not in use” for otherchannels.Furthermore, the technical data and measurements for the selected channels are to becompleted correctly before the configuration is used in a real application.Fig. 3.1.4.2.-3. Defining the analogue channels.Technical dataFig. 3.1.4.2.-4. Defining the rated values for the selected channel.MeasurementsFor information about the special measurements required for each function block, refer to the Technical Descriptions of Functions (CD-ROM 1MRS 750889-MCD).Phase currents and voltagesIf the signal type selected for an analogue channel is to be shown in the MIMIC view via the MMIDATA_ function block (MIMIC dynamic data point), the true RMS mode must be selected in the “Special Measurements” dialogue. Moreover, in case the Inrush3 function block (3-phase transformer inrush and motor start-up current detector) is to be used, the 2nd harmonic restraint must be selected for the analogue channels (IL1, IL2, IL3) used.Fig. 3.1.4.2.-5. Selecting the required special measurement modes for phase current measurement.Neutral currentWhen e.g. the DEF2_ function block (directional earth-fault protection) is going to be used, intermittent earth-fault protection must be selected for the channel via which the current Io is measured. Unless intermittent earth-fault protection has been chosen, the following configuration error indication will appear on the display of the relay terminal ( # denotes the number of the analogue channel in question):System: SUPERVCh # errorFig. 3.1.4.2.-6. Selecting the required special measurement modes for neutral current measurement.FrequencyWhen, for example, any of the function blocks MEFR_ (system frequency measure-ment), SCVCSt_ or Freq1St_ is in use, frequency measurement must be selected for the channel via which the voltage is measured for frequency measurement (for example: Channel 10, Voltage Transformer 4, Signal type U3 / Measurements button in the “Con-figuration of REF543” dialogue).Fig. 3.1.4.2.-7. Selecting the required special measurement modes for frequency meas-urement.Virtual channelsIn case no measuring devices are applied for measuring residual voltage (Uo) and neu-tral current (Io), the virtual channels 11 and 12 must be used.Fig. 3.1.4.2.-8. Using virtual channels 11 and 12 in case no measuring devices are applied for measuring Io and Uo.In case of the virtual channel 12, voltage measuring devices must be associated with phase voltages.Fig. 3.1.4.2.-9. Associating voltage measuring devices with phase voltages.After a compiled configuration is downloaded to a relay and the relay is started (storing and resetting are done), it will internally check whether the analogue channels are cor-rectly configured regarding the analogue inputs of function blocks. If the connectedchannels have been configured incorretly, the ERR output signal of the specific function block goes active and the event E48 is sent. Furthermore, either the event E13 or E5 is sent depending on the function block in question.Binary inputsThe filter time is set for each binary input of the relay terminal via the resource settings dialogue “Binary Inputs”. Inversion of the inputs can also be set. For further informa-tion refer to the Technical Reference Manual of REF 54_ or REM 543.Fig. 3.1.4.2.-10. Defining the binary inputs.MeasurementsWhen the MEPE7 function block (power and energy measurement) is used, the measur-ing mode must be selected via the resource settings dialogue “Measurements”.Fig. 3.1.4.2.-11. Selecting the measuring mode for power and energy measurement.Condition monitoringValues for the circuit-breaker wear function blocks CMBWEAR 1 and 2 can be set via the resource settings dialogue “Condition Monitoring”.Fig. 3.1.4.2.-12. Setting the values for circuit-breaker wear.3.1.4.3.TasksPrograms and tasksPrograms are associated with tasks via the dialogues Properties/Task and Properties/Program. Cyclic tasks are activated within a specific time interval and the program isexecuted periodically.The two dialogues below illustrate the association of a program type (Prot_Me) with atask (Task1) (see also figure 3.1.4.-1. in section “Physical hardware”).Fig. 3.1.4.3.-1. Naming a cyclic task.Fig. 3.1.4.3.-2. Associating the selected task with the desired program type.Task intervalGenerally, the operation accuracy is increased when the task speed is increased, but atthe same time, the load of the microprocessors is increased as well. Although the taskspeed can be freely chosen with the tool, it is necessary to determine a maximum taskexecution interval for each function block; otherwise the operation accuracy and operatetimes for protection functions cannot be guaranteed. The maximum task executioninterval is based on test results and has also been used in the type testing of the functionblocks. The recommended task execution interval quaranteed by the manufactirer canbe found in section Technical Data in the technical description of each function block.According to the standard, the Relay Configuration Tool includes the possibility ofdefining the tasks on two different levels:1) each POU (= program organisation unit) can be tied to a separate task2) a separate function block inside a POU can be tied to any taskHowever, the alternative 2) is not yet supported in the RED environment, which meansthat if a separate function block inside a POU is given a separate task definition, it willbe ignored when transferred to the relay. This means that when the function blocks arebeing placed in different POUs, not only the category of the function (protection, con-trol, etc.) but also the maximum task execution interval should be considered since allfunction blocks inside a POU will run at the same speed.For further information about the microprocessor loads and task execution intervals offunction blocks refer to the manual “Technical Descriptions of Functions, Introduction”(CD-ROM: Technical Descriptions of Functions, 1MRS750889-MCD).The task execution interval for each task is defined via the dialogue Properties/Task(click “Settings...”). For example, the task execution interval for Task1 in figure belowis defined as 10 ms, which means that the program Prot_Me is run 100 times per onesecond.Fig. 3.1.4.3.-3. Setting the task execution interval for a program.3.2.Global variablesThe physical contacts of RE_ 54_ are defined in the “Global Variables” worksheet.Declarations for the physical contacts are automatically defined when the correct hard-ware version of RE_ 54_ is selected. Declarations for the analogue channels are createdafter the analogue channel settings defined in the resource settings dialogue have beenapproved.Fig. 3.2-1. Global Variables worksheet.3.3.Declaring variablesAt its beginning, each programmable controller POU type declaration is to contain atleast one declaration part that specifies the types of the variables used in the organisa-tion unit. The declaration part shall have the textual form of one of the keywordsV AR_INPUT, VAR_OUTPUT, V AR and V AR_EXTERNAL followed by one or moredeclarations separated by semicolons and terminated by the keyword END_V AR. Allthe comments you write must be edited in parentheses and asterisks.(**********************************)(*Variable declaration*)(*of REF 541*)(**********************************)Caution is required regarding comments and variable declarations. The following codeexample will be compiled successfully but because of the non-closed comment theEND_VAR - V AR_EXTERNAL couple will be excluded and thus the channel numbersbecome local variables of the POU and they get the initial value zero.V AR (*AUTOINSERT*)NOC3Low_1:NOC3Low; (* Erroneous nonclosed comment *END_VARV AR_EXTERNALU12:SINT;(* Measuring channel 8 *)U23:SINT;(* Measuring channel 9 *)U31:SINT;(* Measuring channel 10 *)END_VARThree examples of creating the textual declaration for different kinds of graphical pro-grams are given below.EXAMPLE 1.•POU type:FBD program •Function block type declaration: VARINPUT1:BOOL :=FALSEINPUT2:BOOL :=FALSEINPUT3:BOOL :=FALSEOUTPUT:BOOL :=FALSE END_VARFig. 3.3-1. Function block image.EXAMPLE 2.•POU type:NOC3Low, manufacturer dependent function block •Function block type declaration:V AR_INPUTIL1:SINT :=0;(* Analogue channel *)IL2:SINT :=0;(* Analogue channel *)IL3:SINT :=0;(* Analogue channel *)BS1:BOOL :=FALSE;(* Blocking signal *)BS2:BOOL :=FALSE;(* Blocking signal *)TRIGG:BOOL :=FALSE;(* Triggering *)GROUP:BOOL :=FALSE;(* Grp1/Grp2 select *)DOUBLE:BOOL :=FALSE;(* Doubling signal *)BSREG:BOOL :=FALSE;(* Blocking registering *)RESET:BOOL :=FALSE;(* Reset signal *)END_VARV AR_OUTPUTSTART:BOOL :=FALSE; (* Start signal *)TRIP:BOOL :=FALSE; (* Trip signal *)CBFP:BOOL :=FALSE; (* CBFP signal *)ERR:BOOL :=FALSE; (* Error signal *)END_VARFig. 3.3-2. Function block image of NOC3Low.EXAMPLE 3.•POU type:Configurer dependent FBD function block CONDIS •Function block type declaration:Fig. 3.3-3. Type declaration of the configurer made function block CONDIS.Fig. 3.3-4. Use of the configurer made function block CONDIS.Fig. 3.3-5. Contents of the CONDIS function block.In the example 3 above, part of the configuration has been separated to a configurermade function block called CONDIS. Such function blocks may not be given namesalready belonging to library functions blocks or IEC standard function blocks. Thefunction block CONDIS has been used like any other function block in the graphicalprogram. The order of inputs of a function block that has been inserted to a worksheetmay not be changed. It must also be remembered that a function block with an instancenamed by the configurer can only be inserted to the project once.3.4.Variables declared as globalThe range of validity of the declarations included in the declaration part shall be“local”to the POU in which the declaration part is contained. One exception to this rule are var-iables that have been declared to be “global”. Such variables are only accessible to aPOU via a V AR_EXTERNAL declaration. The type of a variable declared in aV AR_EXTERNAL block shall agree with the type declared in the V AR_GLOBALblock of the associated program, configuration or resource.Fig. 3.4-1. Local and global variables.The figure above illustrates the ways how values of variables can be communicated among software elements. Variable values within a program can be communicated directly by connecting the output of one program element to the input of another or via local variables such as the variable y illustrated in the upper left corner of the figure above. In the same configuration, variable values can be communicated between pro-grams via global variables such as the variable x illustrated in “Configuration C” in the figure above. In such a case, make sure that the global variable is only written from one location in the project. The global variable can still be read from several locations. Do not use binary inputs or outputs for data transfer between tasks.Despite the fact that according to the IEC standard 1131-3 all local variables that have no initial value are initially FALSE (0), the initial values for all local variables have to be given in the variable worksheet of the logical POU. This is because somewhere in the configuration, especially in the beginning of running the configuration i.e. when the relay is started up, the variable can be used before the initial value has been created for the variable. The initial values for global variables are given in the global variable worksheet (see CASE 1 below).CASE 1. Variables declarationV ARIABLE WORKSHEET of logical POU*********************************************************************V ARTRIPPING:BOOL:= FALSE;BLOCK:BOOL:= TRUE;TMP1:BOOL:= FALSE;END_VARV AR_EXTERNALPS1_4_HSPO1 :BOOL; (* Double pole high speed power output *)(* 4.1/10,11,12,13 *)PS1_4_HSPO2 :BOOL; (* Double pole high speed power output *)(* X4.1/15,16,17,18 *)PS1_4_HSPO3 :BOOL; (* Double pole high speed power output *)(* X4.1/6,7,8,9 *)END_VARV AR_EXTERNALTCS1_ALARM:BOOL;END_VAR********************************************************************* GLOBAL V ARIABLE WORKSHEET*********************************************************************V AR_GLOBALPS1_4_HSPO1AT %QX 1.1.2 :BOOL := FALSE;(* Double pole high speed power output X4.1/10,11,12,13 *) PS1_4_HSPO2AT %QX 1.2.2 :BOOL := FALSE;(* Double pole high speed power output X4.1/15,16,17,18 *) PS1_4_HSPO3AT %QX 1.3.2 :BOOL := FALSE;(* Double pole high speed power output X4.1/6,7,8,9 *) END_VARV AR_GLOBALTCS1_ALARM:BOOL:= FALSE;END_VAR*********************************************************************piling the projectThe “Build Project” mode in the “Make” menu is used to compile the whole project forthe first time after editing, which means compiling all POUs, global variables, resourcesetc., whereas the “Make” mode can be used to compile the worksheets that have beenedited. The changed worksheets are marked with an asterisk in the project tree editor.“Make” is the standard mode for compiling and should normally be used when you havefinished editing.In the Relay ConfigurationTool you can view the execution order of the different func-tions or function blocks in your worksheet. The execution order corresponds to theintermediate PLC code created while compiling. Note that the execution order can onlybe seen if you have already compiled the worksheet using the menu item “CompleteWorksheet” in the submenu “Make”.By editing the mwt.ini file, one can affect the execution order. The line below can beadded to section [MAKE]:SH_EXECUTION_ORDER_TOP_BOTTOMSets the order of execution of functions and function blocks in graphical editor0Sets the execution order from left to right1Sets the execution order from top to bottomThe default value is …0“. The execution order can only be changed when compiling aworksheet again.4.Main Configuration Rules for RE_ 54_4.1.General Make sure that all analogue signals are connected and all necessary inputs and outputs are wired. Note that the outputs of function blocks may not be connected together. There are also many other FBD programming rules to follow. One of the most typical rules is not to use the “wired-OR” connection. All signals that are connected to the same output signal (both output relays and horizontal communication outputs) must be connected via an OR-gate (see figure below).Fig. 4.1-1. Use of an explicit Boolean OR gate (on the right).4.2.Binary inputs Do not write binary inputs - like BIO2_7_BI2.Fig. 4.2-1. Writing global binary inputs is not allowed.Binary inputs can be read from several locations.I>I>>TRIP TRIP PS1_4_HSPO1PS1_4_HSPO1I>I>>TRIP TRIP PS1_4_HSPO1"wired-OR" structure is not allowed an explicit Boolean "OR" block is required instead ORFig. 4.2-2. Correct way of using global binary inputs.4.3.Explicit feedbackAn explicit feedback loop may not be used. In case the tool gives a warning about thefeedback loop after compiling, the loop must be broken up by connecting the input ofthe function block and the output of another function block separately to the auxiliaryvariable.Fig. 4.3-1. Explicit feedback loop is not allowed.Fig. 4.3-2. Explicit feedback via the auxiliary variable FEEDBACK.4.4.Measurement function blocksAll the measurement inputs of the function blocks must be connected. In case e.g. thethree-phase current measurement function block MECU3A is implemented by twophases of currents, one of the currents available must be connected to the remainingthird input of MECU3A. Unless something is connected to the third current input, thefunction block will attempt to use the sensor channel 1 instead of the empty channel,and if no measurements have been defined for channel 1, a supervision error will result.4.5.WarningsIn case of the indication “Warning: Instance ‘xx’ is never used” in connection with Array compilation, remove the corresponding instances of the function block from the varia-bles worksheet of the POU. The tool will not give a separate warning for unused varia-bles, which is why they need to be removed manually. When a global variable is addedto a sheet as a copy-paste -function, the global radio button has to be chosen (see figurebelow); otherwise the variable becomes a local variable of the POU, which is due to theauto-insert feature of the tool (global variable = V AR_EXTERNAL, local variable =V AR).Fig. 4.5-1. Copying a global variable to a worksheet of a POU.4.6.Execution orderCheck the execution order after the compilation. The connection of simple variables toeach other generates a code, the execution order of which in relation to the callingsequence of POUs cannot be seen by means of the Layout Execution Order function.Fig. 4.6-1. The INTERLOCKING variable is updated (TMP1) during the task executioncycle (see the execution order 1,2,3).In addition, the execution order may be illogical or even incorrect considering the func-tionality.Fig. 4.6-2. The explicit feedback (TMP1) delays the updating of the INTERLOCKINGvariable by one task execution cycle.If the MOVE function is used instead of direct connection, the execution order can beutilised in concluding whether the result is desirable.4.7.F-keyThe freely programmable F-key is declared as VAR_GLOBAL in the global variableworksheet as follows:F001V021:BOOL:=0;(* Free configuration point (F-key) *)The F-key parameter can be added to the configuration logic as an external variable(V AR_EXTERNAL). Similar parameters that can be inserted to a relay logic are listedbelow:F001V011:BOOL:=0;(*(W) Resetting of operation indications*)F001V012:BOOL:=0;(*(W) Resetting of operation indications & latched output signals*)F001V013:BOOL:=0;(*(*(W) Resetting of operation indications, latched output signals & wave-form memory*)*)F001V020:BOOL:=0;(*(W) Resetting of accumulated energy measurement*) F001V021:BOOL:=0;(’(R, W) Free configuration point (F-key)*)F002V004:BOOL:=0;(*(*(R, W) Control: Interlocking bypass mode for all control objects (Enables all)*)*)F002V005:USINT:=0;(*(W) Control: Recent control position*) F002V006:BOOL:=0;(*(W) Control: Virtual LON input poll status*)F900V251:BOOL:=0;(*(*(W) Control: Execute all command for selected objects (inside module)*)*)F900V252:BOOL:=0;(*(W) Control: Cancel all command for selected objects (inside module)*)F000V251:BOOL:=0;(*(*(W) Control: Execute all command for selected objects (inside module)*)*)F000V252:BOOL:=0;(*(W) Control: Cancel all command for selected objects (inside module)*)。
随机数 近似熵检测
随机数近似熵检测
随机数是指在一定范围内以随机方式产生的数字或数值序列。
近似熵检测是一种用于分析时间序列数据的方法,它可以用于检测
数据中的随机性和复杂性。
现在让我从多个角度来回答这个问题。
首先,随机数在计算机科学和数学中有着重要的应用。
在计算
机编程中,随机数经常被用来模拟随机事件或者生成随机样本。
这
对于模拟实际情况或者进行实验非常有用。
随机数也被广泛应用于
密码学中,用于生成加密密钥和保护数据安全。
其次,近似熵检测是一种用于分析时间序列数据的统计方法。
它可以用来测量数据的复杂性和随机性。
通过计算时间序列数据中
的模式和规律,近似熵检测可以帮助我们理解数据的特性,例如是
否存在周期性、趋势或者随机噪声。
这对于金融市场分析、医学数
据分析以及工程领域的信号处理都有着重要的应用。
另外,随机数生成器的质量对于近似熵检测也有着重要的影响。
如果随机数生成器产生的随机数不够均匀或者不够随机,那么在进
行近似熵检测时可能会出现偏差或者误差。
因此,确保随机数的质
量对于数据分析和统计推断是非常重要的。
总的来说,随机数和近似熵检测都是数据分析和统计领域中非常重要的概念。
它们在计算机科学、数学、金融、医学等领域都有着广泛的应用。
通过深入理解随机数和近似熵检测的原理和方法,我们可以更好地理解和分析数据,从而做出更准确的推断和预测。
专八英语阅读
英语专业八级考试TEM-8阅读理解练习册(1)(英语专业2012级)UNIT 1Text AEvery minute of every day, what ecologist生态学家James Carlton calls a global ―conveyor belt‖, redistributes ocean organisms生物.It’s planetwide biological disruption生物的破坏that scientists have barely begun to understand.Dr. Carlton —an oceanographer at Williams College in Williamstown,Mass.—explains that, at any given moment, ―There are several thousand marine species traveling… in the ballast water of ships.‖ These creatures move from coastal waters where they fit into the local web of life to places where some of them could tear that web apart. This is the larger dimension of the infamous无耻的,邪恶的invasion of fish-destroying, pipe-clogging zebra mussels有斑马纹的贻贝.Such voracious贪婪的invaders at least make their presence known. What concerns Carlton and his fellow marine ecologists is the lack of knowledge about the hundreds of alien invaders that quietly enter coastal waters around the world every day. Many of them probably just die out. Some benignly亲切地,仁慈地—or even beneficially — join the local scene. But some will make trouble.In one sense, this is an old story. Organisms have ridden ships for centuries. They have clung to hulls and come along with cargo. What’s new is the scale and speed of the migrations made possible by the massive volume of ship-ballast water压载水— taken in to provide ship stability—continuously moving around the world…Ships load up with ballast water and its inhabitants in coastal waters of one port and dump the ballast in another port that may be thousands of kilometers away. A single load can run to hundreds of gallons. Some larger ships take on as much as 40 million gallons. The creatures that come along tend to be in their larva free-floating stage. When discharged排出in alien waters they can mature into crabs, jellyfish水母, slugs鼻涕虫,蛞蝓, and many other forms.Since the problem involves coastal species, simply banning ballast dumps in coastal waters would, in theory, solve it. Coastal organisms in ballast water that is flushed into midocean would not survive. Such a ban has worked for North American Inland Waterway. But it would be hard to enforce it worldwide. Heating ballast water or straining it should also halt the species spread. But before any such worldwide regulations were imposed, scientists would need a clearer view of what is going on.The continuous shuffling洗牌of marine organisms has changed the biology of the sea on a global scale. It can have devastating effects as in the case of the American comb jellyfish that recently invaded the Black Sea. It has destroyed that sea’s anchovy鳀鱼fishery by eating anchovy eggs. It may soon spread to western and northern European waters.The maritime nations that created the biological ―conveyor belt‖ should support a coordinated international effort to find out what is going on and what should be done about it. (456 words)1.According to Dr. Carlton, ocean organism‟s are_______.A.being moved to new environmentsB.destroying the planetC.succumbing to the zebra musselD.developing alien characteristics2.Oceanographers海洋学家are concerned because_________.A.their knowledge of this phenomenon is limitedB.they believe the oceans are dyingC.they fear an invasion from outer-spaceD.they have identified thousands of alien webs3.According to marine ecologists, transplanted marinespecies____________.A.may upset the ecosystems of coastal watersB.are all compatible with one anotherC.can only survive in their home watersD.sometimes disrupt shipping lanes4.The identified cause of the problem is_______.A.the rapidity with which larvae matureB. a common practice of the shipping industryC. a centuries old speciesD.the world wide movement of ocean currents5.The article suggests that a solution to the problem__________.A.is unlikely to be identifiedB.must precede further researchC.is hypothetically假设地,假想地easyD.will limit global shippingText BNew …Endangered‟ List Targets Many US RiversIt is hard to think of a major natural resource or pollution issue in North America today that does not affect rivers.Farm chemical runoff残渣, industrial waste, urban storm sewers, sewage treatment, mining, logging, grazing放牧,military bases, residential and business development, hydropower水力发电,loss of wetlands. The list goes on.Legislation like the Clean Water Act and Wild and Scenic Rivers Act have provided some protection, but threats continue.The Environmental Protection Agency (EPA) reported yesterday that an assessment of 642,000 miles of rivers and streams showed 34 percent in less than good condition. In a major study of the Clean Water Act, the Natural Resources Defense Council last fall reported that poison runoff impairs损害more than 125,000 miles of rivers.More recently, the NRDC and Izaak Walton League warned that pollution and loss of wetlands—made worse by last year’s flooding—is degrading恶化the Mississippi River ecosystem.On Tuesday, the conservation group保护组织American Rivers issued its annual list of 10 ―endangered‖ and 20 ―threatened‖ rivers in 32 states, the District of Colombia, and Canada.At the top of the list is the Clarks Fork of the Yellowstone River, whereCanadian mining firms plan to build a 74-acre英亩reservoir水库,蓄水池as part of a gold mine less than three miles from Yellowstone National Park. The reservoir would hold the runoff from the sulfuric acid 硫酸used to extract gold from crushed rock.―In the event this tailings pond failed, the impact to th e greater Yellowstone ecosystem would be cataclysmic大变动的,灾难性的and the damage irreversible不可逆转的.‖ Sen. Max Baucus of Montana, chairman of the Environment and Public Works Committee, wrote to Noranda Minerals Inc., an owner of the ― New World Mine‖.Last fall, an EPA official expressed concern about the mine and its potential impact, especially the plastic-lined storage reservoir. ― I am unaware of any studies evaluating how a tailings pond尾矿池,残渣池could be maintained to ensure its structural integrity forev er,‖ said Stephen Hoffman, chief of the EPA’s Mining Waste Section. ―It is my opinion that underwater disposal of tailings at New World may present a potentially significant threat to human health and the environment.‖The results of an environmental-impact statement, now being drafted by the Forest Service and Montana Department of State Lands, could determine the mine’s future…In its recent proposal to reauthorize the Clean Water Act, the Clinton administration noted ―dramatically improved water quality since 1972,‖ when the act was passed. But it also reported that 30 percent of riverscontinue to be degraded, mainly by silt泥沙and nutrients from farm and urban runoff, combined sewer overflows, and municipal sewage城市污水. Bottom sediments沉积物are contaminated污染in more than 1,000 waterways, the administration reported in releasing its proposal in January. Between 60 and 80 percent of riparian corridors (riverbank lands) have been degraded.As with endangered species and their habitats in forests and deserts, the complexity of ecosystems is seen in rivers and the effects of development----beyond the obvious threats of industrial pollution, municipal waste, and in-stream diversions改道to slake消除the thirst of new communities in dry regions like the Southwes t…While there are many political hurdles障碍ahead, reauthorization of the Clean Water Act this year holds promise for US rivers. Rep. Norm Mineta of California, who chairs the House Committee overseeing the bill, calls it ―probably the most important env ironmental legislation this Congress will enact.‖ (553 words)6.According to the passage, the Clean Water Act______.A.has been ineffectiveB.will definitely be renewedC.has never been evaluatedD.was enacted some 30 years ago7.“Endangered” rivers are _________.A.catalogued annuallyB.less polluted than ―threatened rivers‖C.caused by floodingD.adjacent to large cities8.The “cataclysmic” event referred to in paragraph eight would be__________.A. fortuitous偶然的,意外的B. adventitious外加的,偶然的C. catastrophicD. precarious不稳定的,危险的9. The owners of the New World Mine appear to be______.A. ecologically aware of the impact of miningB. determined to construct a safe tailings pondC. indifferent to the concerns voiced by the EPAD. willing to relocate operations10. The passage conveys the impression that_______.A. Canadians are disinterested in natural resourcesB. private and public environmental groups aboundC. river banks are erodingD. the majority of US rivers are in poor conditionText CA classic series of experiments to determine the effects ofoverpopulation on communities of rats was reported in February of 1962 in an article in Scientific American. The experiments were conducted by a psychologist, John B. Calhoun and his associates. In each of these experiments, an equal number of male and female adult rats were placed in an enclosure and given an adequate supply of food, water, and other necessities. The rat populations were allowed to increase. Calhoun knew from experience approximately how many rats could live in the enclosures without experiencing stress due to overcrowding. He allowed the population to increase to approximately twice this number. Then he stabilized the population by removing offspring that were not dependent on their mothers. He and his associates then carefully observed and recorded behavior in these overpopulated communities. At the end of their experiments, Calhoun and his associates were able to conclude that overcrowding causes a breakdown in the normal social relationships among rats, a kind of social disease. The rats in the experiments did not follow the same patterns of behavior as rats would in a community without overcrowding.The females in the rat population were the most seriously affected by the high population density: They showed deviant异常的maternal behavior; they did not behave as mother rats normally do. In fact, many of the pups幼兽,幼崽, as rat babies are called, died as a result of poor maternal care. For example, mothers sometimes abandoned their pups,and, without their mothers' care, the pups died. Under normal conditions, a mother rat would not leave her pups alone to die. However, the experiments verified that in overpopulated communities, mother rats do not behave normally. Their behavior may be considered pathologically 病理上,病理学地diseased.The dominant males in the rat population were the least affected by overpopulation. Each of these strong males claimed an area of the enclosure as his own. Therefore, these individuals did not experience the overcrowding in the same way as the other rats did. The fact that the dominant males had adequate space in which to live may explain why they were not as seriously affected by overpopulation as the other rats. However, dominant males did behave pathologically at times. Their antisocial behavior consisted of attacks on weaker male,female, and immature rats. This deviant behavior showed that even though the dominant males had enough living space, they too were affected by the general overcrowding in the enclosure.Non-dominant males in the experimental rat communities also exhibited deviant social behavior. Some withdrew completely; they moved very little and ate and drank at times when the other rats were sleeping in order to avoid contact with them. Other non-dominant males were hyperactive; they were much more active than is normal, chasing other rats and fighting each other. This segment of the rat population, likeall the other parts, was affected by the overpopulation.The behavior of the non-dominant males and of the other components of the rat population has parallels in human behavior. People in densely populated areas exhibit deviant behavior similar to that of the rats in Calhoun's experiments. In large urban areas such as New York City, London, Mexican City, and Cairo, there are abandoned children. There are cruel, powerful individuals, both men and women. There are also people who withdraw and people who become hyperactive. The quantity of other forms of social pathology such as murder, rape, and robbery also frequently occur in densely populated human communities. Is the principal cause of these disorders overpopulation? Calhoun’s experiments suggest that it might be. In any case, social scientists and city planners have been influenced by the results of this series of experiments.11. Paragraph l is organized according to__________.A. reasonsB. descriptionC. examplesD. definition12.Calhoun stabilized the rat population_________.A. when it was double the number that could live in the enclosure without stressB. by removing young ratsC. at a constant number of adult rats in the enclosureD. all of the above are correct13.W hich of the following inferences CANNOT be made from theinformation inPara. 1?A. Calhoun's experiment is still considered important today.B. Overpopulation causes pathological behavior in rat populations.C. Stress does not occur in rat communities unless there is overcrowding.D. Calhoun had experimented with rats before.14. Which of the following behavior didn‟t happen in this experiment?A. All the male rats exhibited pathological behavior.B. Mother rats abandoned their pups.C. Female rats showed deviant maternal behavior.D. Mother rats left their rat babies alone.15. The main idea of the paragraph three is that __________.A. dominant males had adequate living spaceB. dominant males were not as seriously affected by overcrowding as the otherratsC. dominant males attacked weaker ratsD. the strongest males are always able to adapt to bad conditionsText DThe first mention of slavery in the statutes法令,法规of the English colonies of North America does not occur until after 1660—some forty years after the importation of the first Black people. Lest we think that existed in fact before it did in law, Oscar and Mary Handlin assure us, that the status of B lack people down to the 1660’s was that of servants. A critique批判of the Handlins’ interpretation of why legal slavery did not appear until the 1660’s suggests that assumptions about the relation between slavery and racial prejudice should be reexamined, and that explanation for the different treatment of Black slaves in North and South America should be expanded.The Handlins explain the appearance of legal slavery by arguing that, during the 1660’s, the position of white servants was improving relative to that of black servants. Thus, the Handlins contend, Black and White servants, heretofore treated alike, each attained a different status. There are, however, important objections to this argument. First, the Handlins cannot adequately demonstrate that t he White servant’s position was improving, during and after the 1660’s; several acts of the Maryland and Virginia legislatures indicate otherwise. Another flaw in the Handlins’ interpretation is their assumption that prior to the establishment of legal slavery there was no discrimination against Black people. It is true that before the 1660’s Black people were rarely called slaves. But this shouldnot overshadow evidence from the 1630’s on that points to racial discrimination without using the term slavery. Such discrimination sometimes stopped short of lifetime servitude or inherited status—the two attributes of true slavery—yet in other cases it included both. The Handlins’ argument excludes the real possibility that Black people in the English colonies were never treated as the equals of White people.The possibility has important ramifications后果,影响.If from the outset Black people were discriminated against, then legal slavery should be viewed as a reflection and an extension of racial prejudice rather than, as many historians including the Handlins have argued, the cause of prejudice. In addition, the existence of discrimination before the advent of legal slavery offers a further explanation for the harsher treatment of Black slaves in North than in South America. Freyre and Tannenbaum have rightly argued that the lack of certain traditions in North America—such as a Roman conception of slavery and a Roman Catholic emphasis on equality— explains why the treatment of Black slaves was more severe there than in the Spanish and Portuguese colonies of South America. But this cannot be the whole explanation since it is merely negative, based only on a lack of something. A more compelling令人信服的explanation is that the early and sometimes extreme racial discrimination in the English colonies helped determine the particular nature of the slavery that followed. (462 words)16. Which of the following is the most logical inference to be drawn from the passage about the effects of “several acts of the Maryland and Virginia legislatures” (Para.2) passed during and after the 1660‟s?A. The acts negatively affected the pre-1660’s position of Black as wellas of White servants.B. The acts had the effect of impairing rather than improving theposition of White servants relative to what it had been before the 1660’s.C. The acts had a different effect on the position of white servants thandid many of the acts passed during this time by the legislatures of other colonies.D. The acts, at the very least, caused the position of White servants toremain no better than it had been before the 1660’s.17. With which of the following statements regarding the status ofBlack people in the English colonies of North America before the 1660‟s would the author be LEAST likely to agree?A. Although black people were not legally considered to be slaves,they were often called slaves.B. Although subject to some discrimination, black people had a higherlegal status than they did after the 1660’s.C. Although sometimes subject to lifetime servitude, black peoplewere not legally considered to be slaves.D. Although often not treated the same as White people, black people,like many white people, possessed the legal status of servants.18. According to the passage, the Handlins have argued which of thefollowing about the relationship between racial prejudice and the institution of legal slavery in the English colonies of North America?A. Racial prejudice and the institution of slavery arose simultaneously.B. Racial prejudice most often the form of the imposition of inheritedstatus, one of the attributes of slavery.C. The source of racial prejudice was the institution of slavery.D. Because of the influence of the Roman Catholic Church, racialprejudice sometimes did not result in slavery.19. The passage suggests that the existence of a Roman conception ofslavery in Spanish and Portuguese colonies had the effect of _________.A. extending rather than causing racial prejudice in these coloniesB. hastening the legalization of slavery in these colonies.C. mitigating some of the conditions of slavery for black people in these coloniesD. delaying the introduction of slavery into the English colonies20. The author considers the explanation put forward by Freyre andTannenbaum for the treatment accorded B lack slaves in the English colonies of North America to be _____________.A. ambitious but misguidedB. valid有根据的but limitedC. popular but suspectD. anachronistic过时的,时代错误的and controversialUNIT 2Text AThe sea lay like an unbroken mirror all around the pine-girt, lonely shores of Orr’s Island. Tall, kingly spruce s wore their regal王室的crowns of cones high in air, sparkling with diamonds of clear exuded gum流出的树胶; vast old hemlocks铁杉of primeval原始的growth stood darkling in their forest shadows, their branches hung with long hoary moss久远的青苔;while feathery larches羽毛般的落叶松,turned to brilliant gold by autumn frosts, lighted up the darker shadows of the evergreens. It was one of those hazy朦胧的, calm, dissolving days of Indian summer, when everything is so quiet that the fainest kiss of the wave on the beach can be heard, and white clouds seem to faint into the blue of the sky, and soft swathing一长条bands of violet vapor make all earth look dreamy, and give to the sharp, clear-cut outlines of the northern landscape all those mysteries of light and shade which impart such tenderness to Italian scenery.The funeral was over,--- the tread鞋底的花纹/ 踏of many feet, bearing the heavy burden of two broken lives, had been to the lonely graveyard, and had come back again,--- each footstep lighter and more unconstrained不受拘束的as each one went his way from the great old tragedy of Death to the common cheerful of Life.The solemn black clock stood swaying with its eternal ―tick-tock, tick-tock,‖ in the kitchen of the brown house on Orr’s Island. There was there that sense of a stillness that can be felt,---such as settles down on a dwelling住处when any of its inmates have passed through its doors for the last time, to go whence they shall not return. The best room was shut up and darkened, with only so much light as could fall through a little heart-shaped hole in the window-shutter,---for except on solemn visits, or prayer-meetings or weddings, or funerals, that room formed no part of the daily family scenery.The kitchen was clean and ample, hearth灶台, and oven on one side, and rows of old-fashioned splint-bottomed chairs against the wall. A table scoured to snowy whiteness, and a little work-stand whereon lay the Bible, the Missionary Herald, and the Weekly Christian Mirror, before named, formed the principal furniture. One feature, however, must not be forgotten, ---a great sea-chest水手用的储物箱,which had been the companion of Zephaniah through all the countries of the earth. Old, and battered破旧的,磨损的, and unsightly难看的it looked, yet report said that there was good store within which men for the most part respect more than anything else; and, indeed it proved often when a deed of grace was to be done--- when a woman was suddenly made a widow in a coast gale大风,狂风, or a fishing-smack小渔船was run down in the fogs off the banks, leaving in some neighboring cottage a family of orphans,---in all such cases, the opening of this sea-chest was an event of good omen 预兆to the bereaved丧亲者;for Zephaniah had a large heart and a large hand, and was apt有…的倾向to take it out full of silver dollars when once it went in. So the ark of the covenant约柜could not have been looked on with more reverence崇敬than the neighbours usually showed to Captain Pennel’s sea-chest.1. The author describes Orr‟s Island in a(n)______way.A.emotionally appealing, imaginativeB.rational, logically preciseC.factually detailed, objectiveD.vague, uncertain2.According to the passage, the “best room”_____.A.has its many windows boarded upB.has had the furniture removedC.is used only on formal and ceremonious occasionsD.is the busiest room in the house3.From the description of the kitchen we can infer that thehouse belongs to people who_____.A.never have guestsB.like modern appliancesC.are probably religiousD.dislike housework4.The passage implies that_______.A.few people attended the funeralB.fishing is a secure vocationC.the island is densely populatedD.the house belonged to the deceased5.From the description of Zephaniah we can see thathe_________.A.was physically a very big manB.preferred the lonely life of a sailorC.always stayed at homeD.was frugal and saved a lotText BBasic to any understanding of Canada in the 20 years after the Second World War is the country' s impressive population growth. For every three Canadians in 1945, there were over five in 1966. In September 1966 Canada's population passed the 20 million mark. Most of this surging growth came from natural increase. The depression of the 1930s and the war had held back marriages, and the catching-up process began after 1945. The baby boom continued through the decade of the 1950s, producing a population increase of nearly fifteen percent in the five years from 1951 to 1956. This rate of increase had been exceeded only once before in Canada's history, in the decade before 1911 when the prairies were being settled. Undoubtedly, the good economic conditions of the 1950s supported a growth in the population, but the expansion also derived from a trend toward earlier marriages and an increase in the average size of families; In 1957 the Canadian birth rate stood at 28 per thousand, one of the highest in the world. After the peak year of 1957, thebirth rate in Canada began to decline. It continued falling until in 1966 it stood at the lowest level in 25 years. Partly this decline reflected the low level of births during the depression and the war, but it was also caused by changes in Canadian society. Young people were staying at school longer, more women were working; young married couples were buying automobiles or houses before starting families; rising living standards were cutting down the size of families. It appeared that Canada was once more falling in step with the trend toward smaller families that had occurred all through theWestern world since the time of the Industrial Revolution. Although the growth in Canada’s population had slowed down by 1966 (the cent), another increase in the first half of the 1960s was only nine percent), another large population wave was coming over the horizon. It would be composed of the children of the children who were born during the period of the high birth rate prior to 1957.6. What does the passage mainly discuss?A. Educational changes in Canadian society.B. Canada during the Second World War.C. Population trends in postwar Canada.D. Standards of living in Canada.7. According to the passage, when did Canada's baby boom begin?A. In the decade after 1911.B. After 1945.C. During the depression of the 1930s.D. In 1966.8. The author suggests that in Canada during the 1950s____________.A. the urban population decreased rapidlyB. fewer people marriedC. economic conditions were poorD. the birth rate was very high9. When was the birth rate in Canada at its lowest postwar level?A. 1966.B. 1957.C. 1956.D. 1951.10. The author mentions all of the following as causes of declines inpopulation growth after 1957 EXCEPT_________________.A. people being better educatedB. people getting married earlierC. better standards of livingD. couples buying houses11.I t can be inferred from the passage that before the IndustrialRevolution_______________.A. families were largerB. population statistics were unreliableC. the population grew steadilyD. economic conditions were badText CI was just a boy when my father brought me to Harlem for the first time, almost 50 years ago. We stayed at the hotel Theresa, a grand brick structure at 125th Street and Seventh avenue. Once, in the hotel restaurant, my father pointed out Joe Louis. He even got Mr. Brown, the hotel manager, to introduce me to him, a bit punchy强力的but still champ焦急as fast as I was concerned.Much has changed since then. Business and real estate are booming. Some say a new renaissance is under way. Others decry责难what they see as outside forces running roughshod肆意践踏over the old Harlem. New York meant Harlem to me, and as a young man I visited it whenever I could. But many of my old haunts are gone. The Theresa shut down in 1966. National chains that once ignored Harlem now anticipate yuppie money and want pieces of this prime Manhattan real estate. So here I am on a hot August afternoon, sitting in a Starbucks that two years ago opened a block away from the Theresa, snatching抓取,攫取at memories between sips of high-priced coffee. I am about to open up a piece of the old Harlem---the New York Amsterdam News---when a tourist。
jmeter 科学计数法
jmeter 科学计数法
JMeter是一款功能强大的性能测试工具,它可以帮助开发人员在测试应用程序时测量其各个方面的性能。
其中一个常用的功能是将结果以科学计数法的形式显示。
科学计数法是一种常用的表示极大或极小数量的方法,通过指数形式表示量级。
例如,1.23 x 10^6表示1,230,000,而5.67 x 10^-4表示0.000567。
JMeter将结果以科学计数法的形式显示有助于测试人员更好地理解测试结果。
它可以将相对较小的数字转换为指数形式,而不是显示许多零,从而使数据更加易于阅读。
它还可以将相对较大的数字缩小为易于阅读的格式,而不会占用太多屏幕空间。
要启用JMeter的科学计数法功能,用户需要在jmeter.properties文件中添加以下行:
jmeter.save.saveservice.number.format=scientist
这将启用默认数值格式,使用科学计数法。
如果用户想要设置特定的数值格式,可以根据需要更改
jmeter.save.saveservice.number.format属性。
总之,JMeter的科学计数法功能可以让测试人员更轻松地理解测试结果。
它可以将数据转换为易于理解的形式,从而帮助测试人员更好地分析应用程序的性能并识别问题。
数与运算一致性国外研究现状
数与运算一致性国外研究现状数与运算一致性研究是一个在多学科、多领域中相对新的研究领域,它研究的是数量的多样性、及其发生过程中的一致性问题。
随着社会发展的推动,研究者们以及越来越深入的研究了这一领域。
近年来,国际上的学者们也在重点研究这一领域,研究成果日益丰硕。
在这一新兴领域中,一般来说,研究者们可以从三个层面对数与运算一致性进行研究。
首先,在研究过程中,学者们需要弄清楚数据的特点、模式和规律,以及与其他属性之间的关系。
其次,研究者们需要设计合适的模型来描述和研究这些属性之间的关系。
最后,学者们需要基于模型来探索和推导出具体的一致性原理、理论等。
在近年来,国外的研究者们以各种不同的方式探索并研究了数与运算一致性。
他们使用了各种不同的算法,如模型检验、概率计算、机器学习等,来检验和评估数据的一致性。
比如,有一项研究有关如何用模型检验的方法来识别社会、经济以及政治等领域的一致性,从而给数据提供有效的知识支持。
另一项研究则基于概率计算方法来探索群体事件的一致性,从而帮助我们更好的理解和处理复杂的事件。
还有一项研究则以机器学习方法来构造出一个可以实时检测一致性及其变化的模型,把数据及其分析结果反映到实际应用中,以更好、更有效的方式解决实际问题。
此外,相关研究还有很多有意思的方面。
有的研究利用一些非传统的方法,如社会网络分析,以更加准确的识别出一致性的影响力及其影响下的隐藏关系。
另外,有一些研究对互联网时代人们行为的一致性做了深入的研究,比如研究在网络环境下投票行为的一致性,以及它对网络上的信息共享、网络社交等现象的影响。
总而言之,近年来国外学者们在数与运算一致性研究领域取得了积极的进展,开拓性的研究成果也为社会和人们的生活带来了非常大的价值。
国外的研究者们还在不断地探索新的方法和模式,来检测、分析和研究一致性的属性及其影响,这些新的研究将会在不久的将来给我们带来更加鲜活而丰富的新知识。
如何在马尔可夫链蒙特卡洛中处理缺失数据问题(四)
在马尔可夫链蒙特卡洛(MCMC)方法中,处理缺失数据问题是一个关键的挑战。
缺失数据是指在数据集中某些变量的取值是未知的或者缺失的情况。
在实际应用中,缺失数据是非常常见的,因此如何有效地处理缺失数据对于MCMC方法的应用至关重要。
首先,我们需要了解缺失数据的类型。
缺失数据可以分为完全随机缺失、随机缺失和非随机缺失三种类型。
完全随机缺失是指数据缺失的概率与观测值本身无关,这种情况下我们可以直接忽略缺失数据。
随机缺失是指数据缺失的概率与观测值的其他变量有关,但与缺失值本身无关,这种情况下我们可以通过随机抽样或者插补的方法来处理缺失数据。
非随机缺失是指数据缺失的概率与观测值本身有关,这种情况下缺失数据的处理就比较复杂了。
针对不同类型的缺失数据,我们可以采取不同的处理方法。
对于完全随机缺失,我们可以直接使用MCMC方法进行参数估计,因为缺失数据的存在不会对参数估计造成偏差。
对于随机缺失,我们可以使用插补的方法来处理缺失数据,然后再利用MCMC方法进行参数估计。
而对于非随机缺失,我们则需要考虑更复杂的处理方法。
在处理非随机缺失数据时,我们可以利用MCMC方法中的Gibbs抽样来进行参数估计。
Gibbs抽样是一种通过条件分布来抽样的方法,可以很好地处理包含缺失数据的情况。
具体而言,我们可以将包含缺失数据的变量分解成两部分,一部分是已观测到的变量,另一部分是未观测到的变量。
然后利用Gibbs抽样依次对这两部分变量进行抽样,最终得到参数的后验分布。
这样的处理方法能够很好地利用已观测到的数据来估计未观测到的数据,从而提高参数估计的准确性。
除了Gibbs抽样外,我们还可以利用EM算法来处理非随机缺失数据。
EM算法是一种迭代的优化算法,通过交替进行E步和M步来估计模型参数。
在E步中,我们通过已观测到的数据估计未观测到的数据的条件分布,然后在M步中利用估计出来的未观测数据的条件分布来更新模型参数。
通过不断迭代这两个步骤,最终可以得到模型参数的极大似然估计。
定性数据分析第二章课后答案
第二章课后作业【第1题】解:由题可知消费者对糖果颜色的偏好情况(即糖果颜色的概率分布),调查者取500块糖果作为研究对象,则以消费者对糖果颜色的偏好作为依据,500块糖果的颜色分布如下表1.1所示:表1.1 理论上糖果的各颜色数由题知r=6,n=500,我们假设这些数据与消费者对糖果颜色的偏好分布是相符,所以我们进行以下假设:原假设::0H 类i A 所占的比例为)6,...,1(0==i p p i i 其中i A 为对应的糖果颜色,)6,...,1(0=i p i 已知,1610=∑=i i p 则2χ检验的计算过程如下表所示:在这里6=r 。
检验的p 值等于自由度为5的2χ变量大于等于18.0567的概率。
在Excel 中输入“)5,0567.18(chidist =”,得出对应的p 值为05.00028762.0<<=p ,故拒绝原假设,即这些数据与消费者对糖果颜色的偏好分布不相符。
【第2题】解:由题可知 ,r=3,n=200,假设顾客对这三种肉食的喜好程度相同,即顾客选择这三种肉食的概率是相同的。
所以我们可以进行以下假设:原假设 )3,2,1(31:0==i p H i则2χ检验的计算过程如下表所示:在这里3=r 。
检验的p 值等于自由度为2的2χ变量大于等于15.72921的概率。
在Excel 中输入“)2,72921.15(chidist =”,得出对应的p 值为05.00003841.0<<=p ,故拒绝原假设,即认为顾客对这三种肉食的喜好程度是不相同的。
【第3题】解:由题可知 ,r=10,n=800,假设学生对这些课程的选择没有倾向性,即选各门课的人数的比例相同,则十门课程每门课程被选择的概率都相等。
所以我们可以进行以下假设: 原假设)10,...,2,1(1.0:0==i p H i则2χ检验的计算过程如下表所示:在这里10=r 。
检验的p 值等于自由度为9的2χ变量大于等于5.125的概率。
北语22秋《算法与数据分析》作业1-学习答案
北语22秋《算法与数据分析》作业1
试卷总分:100 得分:100
一、单选题 (共 10 道试题,共 50 分)
1.在下列算法中得到的解未必正确的是
[A.选项]蒙特卡罗算法
[B.选项]拉斯维加斯算法
[C.选项]舍伍德算法
[D.选项]数值概率算法
本题参考选择是:B
2.0-1背包问题的回溯算法所需的计算时间为
[A.选项]O(n2n)
[B.选项]O(nlogn)
[C.选项]O(2n)
[D.选项]O(n)
本题参考选择是:A
3.实现最长公共子序列利用的算法是
[A.选项]分治策略
[B.选项]动态规划法
[C.选项]贪心法
[D.选项]回溯法
本题参考选择是:B
4.以下不可以使用分治法求解的是
[A.选项]棋盘覆盖问题
[B.选项]选择问题
[C.选项]归并排序
[D.选项]0/1背包问题
本题参考选择是:D
5.优先队列式分支限界法选取扩展结点的原则是
[A.选项]先进先出
[B.选项]后进先出
[C.选项]结点的优先级
[D.选项]随机
本题参考选择是:C
6.下列哪一种算法不是随机化算法
[A.选项]蒙特卡罗算法
[B.选项].拉斯维加斯算法
[C.选项].动态规划算法
[D.选项].舍伍德算法
本题参考选择是:C。
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2 work in the limit of large bias applied between the collector and emitter, with the broadened energy levels well inside the bias window. To compare DM/ME- and scattering approaches we consider noninteracting electrons (spin degrees of freedom decouple, we give all results for a single spin direction) throughout this Letter. We note, however, that strong Coulomb blockade can be treated within the DM/ME-approaches along the same lines. Coherent tunneling. The FCS for coherent tunneling through coupled QDs can be obtained from the approach developed by Gurvitz and coworkers in a series of papers [11, 15] (for related work see e.g. Ref. [16]). Starting from the time dependent Schr¨ odinger equation one derives a modified Liouville equation, a system of coupled first order differential equations for DM elements ρN αβ (t0 ) at a given number N of electrons transferred through the QD system at time t0 . Here α, β ∈ {a, b, c, d}, where a, b, c and d denote the Fock-states |00 , |10 , |01 , |11 of the system, i.e., no electrons, one electron in the first dot, one in the second dot, and one in each dot, respectively. The probability distribution is then directly given N N N by P (N, t0 ) = ρN aa (t0 ) + ρbb (t0 ) + ρcc (t0 ) + ρdd (t0 ). The FCS is formally obtained by first Fourier transforming iN χ the DM elements as ραβ (χ, t0 ) = N ρN . This αβ (t0 )e gives the Fourier transformed equation ρ ˙ = Lc (χ)ρ, with −Γe 0 Γc eiχ 0 0 0 iχ Γe 0 0 Γc e 0 2Ω 0 0 −2Γ 0 0 −2Ω 0 0 Γe − Γc 0 0 0 0 0 0 −Γ −∆ε 0 −Ω Ω 0 ∆ε −Γ
arXiv:cond-mat/0507403v1 [cond-mat.mes-hall] 17 Jul 2005
We theoretically consider charge transport through two quantum dots coupled in series. The corresponding full counting statistics for noninteracting electrons is investigated in the limits of sequential and coherent tunneling by means of a master equation approach and a density matrix formalism, respectively. We clearly demonstrate the effect of quantum coherence on the zero-frequency cumulants of the transport process, focusing on noise and skewness. Moreover, we establish the continuous transition from the coherent to the incoherent tunneling limit in all cumulants of the transport process and compare this with decoherence described by a dephasing voltage probe model.
generating function (CGF) F (χ) is [2] exp [−F (χ)] = P (N, t0 ) exp [iN χ]
N
(1)
Here we consider the zero frequency limit, i.e. t0 much longer than the time for tunneling through the system. From the CGF we can obtain the cumulants Ck = −(−i∂χ )k F (χ)|χ=0 which are related to e.g. the average current I = eC1 /t0 and to the zero-frequency noise S = 2e2 C2 /t0 . The Fano factor is defined as C2 /C1 . The skewness of the distribution of transferred charges is given by the third-order cumulant C3 . The setup of the coupled QD system is shown as the inset of Fig. 1: QD1 is connected to the emitter with a tunneling rate Γe and QD2 to the collector contact with rate Γc . Mutually they are coupled by the tunnel matrix element Ω. One level in each dot, at energies ε1 and ε2 respectively, is assumed. We consider zero temperature and
0
Log(P)/(Γ0t0)
-1
-2 Γϕ/Γ=0 Γe Ω
QD1
Ω/Γ=0.5 ME DM 5 20
-3 -4
e
QD2
Γc
c
0
1
2
I/(eΓ0)=N/(Γ0t0)
34ຫໍສະໝຸດ FIG. 1: (Color online) Current statistics for Ω/Γ = 0.5 and for various dephasing rates Γϕ /Γ =0, 5, 20; dashed lines: master equation (ME) approach, solid lines: density matrix (DM) formalism; on-resonance ∆ε = 0, symmetric contact coupling: Γ = Γe = Γc . Γ0 ≡ (2ΓΩ2 )/[4Ω2 + Γ(Γ + Γϕ )]. Inset: Setup of the coupled QD system with (e)mitter and (c)ollector contact and mutual coupling Ω.
PACS numbers: 72.70.+m,73.23.-b,73.63.Kv,74.40.+k
Introduction. The analysis of current fluctuations in mesoscopic conductors provides detailed insight into the nature of charge transfer [1, 2]. The complete information is available by studying the full counting statistics (FCS), i.e. by the knowledge of all cumulants of the distribution of the number of transferred charges [2, 3]. As a crucial achievement, the measurement of the third-order cumulant of transport through a single tunnel junction was recently reported [4]. To what extent one can extract informations from current fluctuations about quantum coherence and decoherence is the subject of intense theoretical investigations: e.g. dephasing in mesoscopic cavities and Aharonov-Bohm rings [5] and decoherence in a Mach-Zehnder interferometer [6]. Quantum dots (QDs) constitute a representative system for mesoscopic conductors. Recently, the real-time tunneling of single electrons could be observed in QDs [7] providing an important step towards an experimental observation of the FCS. For single dots the FCS is known to display no effects of quantum coherence [8, 9]. In contrast, in serially-coupled double QDs [10] the superposition between states from both dots causes prominent coherent effects. Noise properties have been studied theoretically both in the low [11] and finite frequency range [12, 13] for these structures but no FCS studies are available yet. Experimentally, the low-frequency noise has been investigated very recently in related double-well junctions [14]. In this Letter we show that detailed information about quantum coherence in double QD systems can be extracted from the zero-frequency current fluctuations. For this purpose we elaborate on the FCS in the limits of coherent and incoherent transport through the QD system by means of a density matrix (DM) and master equation (ME) description. We demonstrate a smooth transition between these approaches by decoherence originating from coupling the QDs to a charge detector. The results are compared to a scattering approach, where decoherence is introduced via phenomenological voltage probes. Model. The central quantity in the FCS is P (N, t0 ), the distribution function of the number N of transferred charges in the time interval t0 . The associated cumulant