Fyind's Blog

Keyboard undefined 问候 Bonsoir! Tu vas bien? - Oui, et tui? Bonsua, Tue va bian, we, e tua Salut ! Ça va? Ça va, Et tui. salu sa va, sa va etua Bonjour, vous allez bien? vo sa le bian Au revoir! Salut! o revoa salu 词性 阳: un tableau 黑板 an tablu un ordinateur 笔记本电脑 an nordinater un smartphone 手机 un cahier 笔记本 an kaye un livre 书 lievra un stylo 圆珠笔 stilo un crayon 铅笔 creyong 阴 une chaise 椅子 uen shese une table 桌子 tabla une tablette 平板电脑 tablete 字母表 和德语不同的 C, E, ...

Matrix Algebra 列表示 \[ A=\left[\begin{array}{llll} \mathbf{a}_1 & \mathbf{a}_2 & \cdots & \mathbf{a}_n \end{array}\right] \] 定理 基本运算 Let \(A,B,C\) be matrices of the same size, and \(r,s\) be scalars \(A+B=B+A\) \((A+B)+C=A+(B+C)\) \(A+0=A\) \(r(A+B)=rA+rB\) \((r+s)A = rA + sA\) \(r(sA)=(rs)A\) scalar 可以交换位置 \[ \lambda(\boldsymbol{B} \boldsymbol{C})=(\lambda \boldsymbol{B}) \boldsymbol{C}=\boldsymbol{B}(\lambda \boldsymbol{C})=(\boldsymbol{B} \boldsymbol{C}) \lambda, \quad \bolds...

嵌入式系统和安全 Introduction Four requirements for embedded system Efficiency, function,dependability, security Relationship between Dependability and security Difference between security and safety Goal of lecture Being able to design secure embedded systems Assess and choose appropriate measures to secure an embedded system Implement given tasks on an embedded system (done) Use toolchains for cross-platform development Discuss memory organization Classify different types of on-chip memory Reca...

现代c++编程 12345#include <print>int main() { std::println("Hello world!");} 编译 1c++ -std=c++23 -Wall -Werror first.cpp -o first 运行 1./first 编译和运行 image-20231019093714449 首先被编译成object code 然后linker会link一些库最后编程可执行文件 translation unit: input of compiler object code is the output of compiler #include is done vis the preprocessor (literally included = long compilation time) compiler uses the declaration to know the signature of object, not resolve external thing linker ch...

二项式反演 对于某些问题，比较容易计算 钦定 \(k\) 个位置的可能性 而比较难计算 有 \(k\) 个位置的可能性 这个时候可以用二项式反演对问题进行转化 形式2 一共有 \(n\) 个元素，设 \(f(k)\) 是钦定 \(k\) 个元素的方法数，\(g(k)\) 是恰好选 \(k\) 个元素的方法数，那么有如下关系 \[ f(k) =\sum_{i=k}^n\left(\begin{array}{l}i \\k\end{array}\right) g(i) \Leftrightarrow g(k) = \sum_{i=k}^n (-1)^{i-k}\left(\begin{array}{l}i \\k\end{array}\right) f(i) \] 每个 \(g(i)\) 有 \(\left(\begin{array}{l}i \\k\end{array}\right)\) 种钦定方法 例子 \((a,b,c,d)\) 中求 \(f(2)\) 和 \(g(2)\) 钦定 \((a,b)\) , \((a,c)\), \((a,d)\) , \((b,c)\) ...

硬件安全 安全的定义 Create, maintain and attest a secure state for an embedded device Ensure confidentiality, integrity and availability of the data processed on the device Ensure the safety of the people and the environment interacting with the device Protect the device itself, its environment and other data from processed malicious data Abstraction Layers and Attack Vectors skipped Secure Embedded System Design Typical Criteria Time to market Design + manufacturing setup cost Component + manufact...

模拟电子技术 本征半导体 本征半导体是纯净的具有晶体结构的半导体。 载流子：运载电荷的粒子称为载流子。导体导电只有一种载流子, 即自由电子导电; 空穴：当电子挣脱共价键的束缚变成为自由电子后，在共价键中留下一个空位置，称为空穴

密码学 理论基础 Alice 给 Bob 发消息，保护消息的 confidentiality. 传输途径可以是任意的，Internet, USB stick… 在过程中被动的监听者Eve 有可能会监听或者解释信息. 在过去，军事加密依赖于信息的混乱程度 obfuscation of message contents. 现代密码学依赖于 Kerckhoff’s Principle, 除了key所有信息都是已知的. A crypto system should be secure, even if everything about the system, except the key, is public knowledge. 信息加密是通过 encryption schemes 使用一个key和lock concept来实现的. 只有key的持有者可以加密解密信息. Alice会把key \(k\) 分享给Bob, 我们现在还不关系这个怎样实现. Alice 加密信息 \(m\), \(c := E(k,m)\) Bob 解密信息 \(m:=D(k,c)\) 香农密码 Sh...

高效算法II 线性规划(LP) Standard Form input: number \(a_{ij},c_j,b_j\) output: numbers \(x_j\) \(n = \#decision variables, m=\#conatrains\) \(\begin{aligned} & \max \sum_{j=1}^n c_j x_j \\ & \text { s.t. } \sum_{j=1}^n a_{i j} x_j=b_i \quad 1 \leq i \leq m \\ & x_j \geq 0 \quad 1 \leq j \leq n \\ & \end{aligned}\) 也可以用矩阵的写法 \(\begin{array}{rr}\max & c^T x \\ \text { s.t. } \quad A x=b \\ & x \geq 0\end{array}\) 转换成Standard Form 小于等于 \(a-3b+5c\le 12\) 变成 \(a-3b+5c+s=12,s \ge 0...

客制化键盘设计 设计布局 这个网站 可以在线设计布局，设计完成之后可以复制 Raw Data 来进行下一步。 image-20230419164533764 123456["Esc",{x:1},"F1","F2","F3","F4",{x:0.5},"F5","F6","F7","F8",{x:0.5},"F9","F10","F11","F12",{x:0.25},"PrtSc","Scroll Lock","Pause\nBreak"],[{y:0.5},"~\n`","!\n1","@\n2",...