265 Matching Annotations
  1. Last 7 days
  2. May 2021
    1. Markov chain with the same boundary values.

      harmonic is unique

    2. This current is

      $$ \begin{aligned} i_a &= \sum_y(v_a-v_y)C_{ay} \\ & = v_a\sum_yC_{ay} - \sum_y v_yC_{ay} \\ & = C_a v_a - \sum_y v_y P_{ay} C_a \\ & = C_a (1 - \sum_y P_{ay} v_y) \end{aligned} $$

    3. flowing into

      the current is from outside source

  3. Apr 2021
    1. which stores the last operationfrom thesametransaction


    2. status:

      事务的三种状态: 运行中, 提交中, 终止中

    3. a sequence of log records

      Log record 类型

      • UPDATE
      • COMMIT
      • ABORT
      • END
      • CLR
    4. how a database can abort a transaction


      • 死锁
      • 用户主动终止
      • 操作违反约束
      • 系统崩溃
    5. what inequality must hold
      1. 所有被写入磁盘的日志的序列号都 <= flushedLSN
      2. 日志被数据先写入磁盘
    6. prevLSN
      • flushedLSN 保存在内存
      • prevLSN 保存在 log record
      • pageLSN 保存在 data page
    7. crease by 10 each time


    8. two rules
      1. 日志要在数据之前写入磁盘
      2. 当事务提交时所有日志必须写入磁盘
    9. Durability


  4. Jun 2019
    1. The Strategy Pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable. Strategy lets the algorithm vary independently from clients that use it.

      a behavioral pattern

    2. Favor composition over inheritance.

      composition vs inheritance

      • Document title: MCUXpresso SDK USB Stack User’s Guide
      • Document number: MCUXSDKUSBSUG
      • Document version: Rev. 9, December 2018



    1. Full Speed USB connector (USB0)


      • title: LPCXpresso546x8/540xx/54S0xx Board User Manual
      • version: Rev. 2.1—7th January 2019


    1. splinters


    2. block size

      include the header and padding


  5. May 2019
    1. The stator, or stationary part of the stepping motorholds multiple windings. The arrangement of thesewindings is the primary factor that distinguishesdifferent types of stepping motors from an electricalpoint of view.


    2. variable reluctance


    3. stator


    4. rotor


    5. Brushless



    1. The ADC converts an analog input voltage to a 10-bit digital value through successive approximation.

      successive approximation

    2. The ADC contains a Sample and Hold circuit which ensures that the input voltage to the ADC is held at a constant level during conversion.

      Sample and Hold circuit.

    3. 0x08

      TWSR: a START has been trasmitted.


  6. Mar 2019
  7. Feb 2019
    1. any word beginning with an upper-case letter is a Prolog variable
    2. This is the way logical conjunction is expressed in Prolog (that is, the comma means and )
    3. the semicolon ; is the Prolog symbol for or

      how to express disjunction

  8. Oct 2018
    1. the potency of a substance in inhibiting a specific biological or biochemical function


    2. inhibitory concentration


    1. In certain databases the key values may be points in some multi-dimensional space

      what is the best data structure for such search problems?

  9. Sep 2018
    1. it is usual to use a suffix / followed by a number to indicate the predicate’s arity

      后缀 /

  10. people.inf.ethz.ch people.inf.ethz.ch
    1. 2.2.1 Pinhole Camera Model

      $$s\tilde{\mathbf{m}} = \mathbf{A}[\mathbf{R}\ \mathbf{t}]\tilde{M}$$

    2. 2.2.2 Absolute Conic

    1. the :- means implication, the , means conjunction, and the ; means disjunction
      • :-: means implication
      • ; : means conjunction
      • , : means disjunction
    1. This will introduce us to the three basic constructs in Prolog: facts, rules, and queries.

      facts, rules, queries

  11. Aug 2018
    1. network *net = make_network(sections->size - 1);

      网络层数由配置文件中的 section 数决定: net->n = n;

    2. get_network_output_layer
    3. net->outputs = out.outputs;


    1. Enter a directory where you’d like to store your code and run: scrapy startproject tutorial

      创建一个Scrapy project

    2. we want the attribute href


  12. Jul 2018
    1. How big is your cache block

      Cache block size: 2 (in words) = 8 (in bytes)

    2. How much data fits in the WHOLE cache

      Capacity: 8 words = 32 Bytes

    1. Your processor must provide the following outputs


    2. Your processor has 2 inputs

      两个输入: 指令 和 时钟

    1. The __thiscall calling convention is used on member functions and is the default calling convention used by C++ member functions that do not use variable arguments.

      成员函数使用 __thiscall 调用约定

    1. Qt add-ons
      • for specific purposes
    2. Qt essentials
      • general and useful
      • available on all supported platforms
    1. There are a few different options to run GUI applications inside a Docker container like using SSH with X11 forwarding, or VNC but the simplest one that I figured out was to share my X11 socket with the container and use it directly.
      docker run -ti --rm \
             -e DISPLAY=$DISPLAY \
             -v /tmp/.X11-unix:/tmp/.X11-unix \
    1. 2/3" (~ 8.8 x 6.6 mm)

      海康 DS-2CD7A86F-IZ(S) 800万 2/3" CMOS ICR日夜型筒型网络摄像机<br> 镜头参数: 2.8~16mm @F1.4,水平视场角:23.8°~98.5°

      math.atan(8.8 / 2 / 2.8) * 180 / math.pi * 2
  13. Jun 2018
    1. Floating Point Calling Conventions


    2. CPU Registers


    3. The supported data types are as follows




    5. Parameter Passing


    6. Floating Point Instructions


    1. The idea of the numeric_limits<T> trait class is due to John Barton and Lee Nackman


  14. May 2018
    1. 计算机图形显示和图象处理的算法<br>

      英文原版: Algorithms for Graphics and Image Processing <br> see here <br> 作者: Theo Pavlidis

    1. 中文翻译版为: <br> 计算机图形显示和图象处理的算法, 1987, 科学出版社

    2. 这本书涉及了许多图像处理中经典的算法, 包括:

      • 细化 Thinning
      • 边界追踪 Contour Tracing
      • 边界填充 Contour Filling?
    3. Algorithms for Graphics and Image Processing
    1. 机器人机构学的数学基础 - 丁靖军, 刘辛军, 丁希仑, 戴建生 编著 (1-50)

    2. 第1章 绪论

      1.1 机构学与机器人学的发展历史概述

      机构学广义上成为机构与机器科学 (Mechanism and Machine Science)

      • 第一阶段(古世纪--18世纪中叶): Aristotle, Problems of Machines
    1. 机器人机构学的数学基础 - 丁靖军, 刘辛军, 丁希仑, 戴建生 编著 (版权页, 前言页, 目录页)

    1. The chapter 2 (Multilayer Networks) gives a overview of the most prominent <s>convolutional network architectures</s> multilayer architectures.

    1. 49-50<br> George Polya<br>Most famous for his classical problem book (known as Polya-Szego), he is also revered as the godfather of combinatorics.

      L. J. Mordell and Gabor Szego<br>Speaking of Szego, here he is (right). Mordell was a great number theorist, known for, among other things, the deep conjecture (related to Fermat's last "theorem") that was proved by Falting (#579) in 1983.


    1. 577-578<br> J. E. Taylor<br>Jean, another Council shot, works on minimal surfaces; she has been known to talk about soap bubbles, of course, and crystals too.

      R. A. Askey<br>I caught Dick during a Bloomington visit in March 1984. Hist specialty is special functions, such as ultraspherical polynomials and Jocobi polynomials; a part of his work was involved in de Branges' solution of the Bieberbach conjecture.


    1.  Borodovsky  &  Ekisheva  (2006),

      Problems and Solutions in Biological Sequence Analysis

    2. What  is  the  probability  P(S)  that  this  sequence  S  was  generated  by  the  HMM  model?


    3. Viterbi  algorithm

      the probability of the most probable path ending in state \(k\) with observation \(i\) is

      $$ p_l(i,x) = e_l(i)\max_k(p_k(j, x-1)\cdot p_{kl}) $$

      or using the log of the probabilities $$ \ln p_l(i,x) = \ln e_l(i) + \max_k(\ln pk(j, x-1) + \ln p{kl}) $$

    4. HMM  :  Viterbi  algorithm  -­a  toy  example
  15. Apr 2018
    1. two cate-gories.


      1. 将文字当为一般对象采用一般对象的检测范式, 对多方向文字处理有问题
      2. 分割出文字区域再进行复杂的后期处理
  16. Mar 2018
    1. a revolutionary technique(expression tem-plates,invented independently by Todd Veldhuizen-'' andDavid Vandevoorde") could be used to improve dramaticallythe runtime efficiency of high-level C++ code like sumlt.

      expression templates invented independently by Todd Veldhuizen and David Vandevoorde

    1. Beating the Abstraction Penalty in C++ Using Expression Templates,
    2. DisambiguatedGlommableExpressionTemplates

      Disambiguated Glommable Expression Templates, Computers in Physics 11, 263 (1997)

    3. Todd Veldhuizen - Techniques for Scientific C++ (RT542.pdf)

    4. Scienti candEngineeringC++

      Barton and Nackman, Scientific and Engineering C++

  17. eigen.tuxfamily.org eigen.tuxfamily.org
    1. MSVC (Visual Studio), 2010 and newer.

      vs2010 及以上版本

    2. Eigen is a pure template library defined in the headers


    3. Eigen is standard C++98 and so should theoretically be compatible with any compliant compiler.

      C++ 98 标准

    1. expres-sion templates (CIP 10:6, 1996 p. 552; CJP I 1 :3, 1997, p. 263)
      1. Beating the Abstraction Penalty in C++ Using Expression Templates, Computers in Physics 10, 552 (1996)
      2. Disambiguated Glommable Expression Templates, Computers in Physics 11, 263 (1997)
    2. Todd Veldhuizen, the co-discoverer of expres-sion templates (CIP 10:6, 1996 p. 552; CJP I 1 :3, 1997, p. 263), i now a graduate student at the Univer-sity of Waterloo.

      Todd Veldhuizen 创建Blitz++ 时是滑铁卢大学的一名研究生

    1. the checker board

      checker board classification example

    1. Todd Veldhuizen

      Blitz++ is a class library for scientific computing designed by Todd Veldhuizen


      Will C++ be faster than Fortran?

    3. simple analogy

      a good example about the difference of memory

    1. selfadjoint (hermitian) matrices

      埃尔米特矩阵, 自伴随矩阵

      $$A^H = A =\overline{A^T}$$

    1. QR factorization method is more stable

      \(QR\) 分解更稳定

    2. every positive definite matrixAhas positive diagonal elements


    3. gives a practical method for testing positive definiteness

      Cholesky 分解给了一种判断矩阵正定的方法

    4. positive semidefinite, but not positive definite, then it is singular

      正半定矩阵是奇异的 $$ \begin{array}{rl} f(t) =& (x-tAx)^TA(x-tAx)\ =&-2t\Vert Ax\Vert^2 + t^2x^TA^3x \end{array} $$

    1. But online life makes me into a different kind of reader – a cynical one

      但网络生活使我成为一种不同类型的读者, 一个犬儒的人。


    1. All new algorithms in OpenCV are written in C++, so there are no benefits to use OpenCV 3.x in C programs.

      OpenCV 3.x 的算法都是用 C++ 实现的

    1. if (app.metadata && app.metadata.has('dc:title') && app.metadata.get('dc:title') !== 'Untitled') { title = app.metadata.get('dc:title'); }

      the empty dc:title should also be considered as Untitled

    1. While that allows you to use the string class, the relevant operator<< is defined in the <string> header itself, so you must include that manually

      为什么有时候使用visual c++会提示 cout << 不能输出 string 类型: 因为 <iostream> 包含了头文件 <xstring>, 该头文件引入了 string 类型但是未引入 operator<<

    1. Priority Scheduling


    2. TheSJFalgorithm can be either preemptive or nonpreemptive.

      SJF 可以是抢占的也可以是非抢占的

    3. exponential average

      SJF 调度使用之前CPU burst度量值的 指数平均 来预测下一个 burst

    4. FCFSscheduling algorithm is nonpreemptive

      FCFS 调度是非抢占的

    5. Shortest-Job-First Scheduling

      SJF: 最短任务优先调度

    6. First-Come, First-Served Scheduling

      FCFS: 先到先服务调度

    7. short-term scheduler

      也称为CPU调度程序, 完成的功能就是从内存中选择一个 ready 状态的进程开始执行, 并将CPU分配给该进程.



    1. PCB

      Process Control Blocks

    2. Arrival Time (AT), Total CPU Time (TC), CPU Burst (CB) and IO Burst (IO)


    3. first line defines the count of random numbers in the file

      randfile: 第一行定义文件中随机数的个数

    4. One trick to deal with schedulers is to treat nonpreemptive scheduler as preemptive with very large quantum (10K