算法博弈论 W39 Revenue-maximizing auctions
This week Revenue-maximizing DSIC auctions completely different goal than social welfare maximization average-case analysis Review Spectrum auction’s problem: VERY LOW REVENUE Social welfare maximization many applications makes sense even in cases where revenue maximization seems to be more important (e.g. keeping customers compared to competitors) educational value: ideal auctions and ideal mechanisms always exist Single item auction with a single potential buyer revenue? what other truth ...
德语学习 B2 Kapitel 1 Heimat ist ...
Inhalt Neue Heimat Ein Land, viele Sprachen Missverständliches Zu Hause in Deutschland 1-1 Heimat ist … (1) Was bedeutet Heimat? Heimat ist nicht nur das Land, die Stadt oder die Region, aus dem/der eine Person kommt. Es kann auch ein anderer Ort sein, an dem man sich wohlfühlt, weil man dort schon lange lebt und sein soziales Netz dort aufgebaut hat. soziales Netz aufbauen 建立人际关系 z. B. Es fällt mir hart schwer, China zu verlassen. Ich habe meine Familie hier und mein soziales Netz habe ich ...
计算几何 W38 I/O Model and Permutation Lower Bound
课前预习 Random Access Machine Model standard theoretical model of computation infinite memory uniform access cost simple model crucial for success of computer industry Hierarchical Memory modern machines have complicated memory hierarchy levels get larger and slower further away from CPU data moved between levels using large blocks many issues influence performance cache misses, TLB misses, branch mis-predictions etc. Disk access is 10610^6106 slower than main memory access important to st ...
丹麦语 DU 3.1 I klassen 1 Præsentation 2
I klassen 1 Hvordan går det? 你好吗？ Det går godt. Hvad med dig? 我很好。你呢？ bliver 留在 svært 困难的 adj Vi ses. = Hej hej. 再见。 En uge 一周 工作日 Hverdage: mandag, tirsdag, onsdag, torsdag, fredag 周末 Weekend: lørdag, søndag Ting i klassen en bog 书 et hæfte 小册子 en mappe 笔记本 et papir 纸 en blyant 铅笔 en kop 茶杯 et ur 手表 en nøgle 钥匙 en taske 挎包 en ordbog 字典 en kuglepen 签字笔 et penalhus 文具盒 en blyantspidser 削笔刀 et bord 桌子 en stol 椅子 et vindue 窗户 et skab 柜子 en tavle 黑板 et landkort 地图 en dør 门 et viskelæder 橡皮擦 ...
计算机视觉 W38 Convolutional Neural Networks
Convolution disadvantage of fully connected MLP: difficult to detect local features. In fully connected neural network, we need a separate neuron to detect each of the items (same feature appear in different position). a waste of network parameters. Solution: using convolution to identify local features Advantages: fewer trainable params (sparse interactions) Same params reused multiple times (param sharing) translation invariance (equi-variance) 平移不变性 for continue: (f∗g)(t)=∫−∞∞f(τ)g(t−τ)dτ= ...
算法博弈论 W38 Algorithmic mechanism design
Ιωάννης 的可爱🇬🇷口音 exponential 一克斯破烂秀 guarantee 尬兰提 Mechanism design for single-parameter environments 3 goals of mechanism designs: DSIC Social welfare maximization simplicity solution: Myerson’s lemma possible obstacle: computational complexity of the social welfare maximization problem hence, the second and the third goals may not be compatible The Knapsack The Knapsack problem aka 背包问题 A burglar enters a house to steal, with a knapsack that can hold items of total weight WWW the burglar ...
丹麦语 DU 3.1 Præsentation 1
教材 Undervisningsmaterialer På vej til dansk - trin for trin 纸质版一本 275 克朗，我们是教学机构借给我们用的，不能在上面写字。 这个 Synope 出版社的丹麦语教材的官网上有音频。可以自己跟着音频来练习。 电子版在 zlibrary 网站上能找到，就是版本有点老。 Præsentation 1 Hej, jeg hedder … 你好，我叫…… Hvad hedder du? 你叫什么名字？ Alfabetet Aa “诶” Bb Cc Dd Ee “诶” Ff Gg Hh “乎” Ii “咦” Jj “哟” Kk “库” Ll Mm Nn Oo Pp Qq Rr “诶啊” Ss Tt Uu Ww “大步V” Xx Yy “於” Zz Ææ Øø Åå “唔” 丹麦语的发音 Udtale 太难了！！！感觉丹麦语也很喜欢像法语那样联诵 丹麦语的 Yy 相当于德语的 Üü 丹麦语的 Øø 相当于德语的 Öö Konjugation 在同一时态下的不同人称，没有动词变位 好耶:happy: Personlige ...
计算几何 W37 Sorting and Searching in Parallel
阅读材料 prefix sums and their application by Guy E. Blelloch, CMU parallel tasks: building blocks, and merge. dynamic programming & divide and conquer extended from sequential algorithms all-prefix-sums operation on PRAM intro prefix sum operation has many extension: quick-sort, lexical analysis, tree operations… primitive instruction in some machine（原子操作） define: scan operation is an array all-prefix-sums operation. implementation array length n, EREW PRAM, time complexity: O(n/p+log p) bi ...
计算机视觉 W37 Neural Networks
Decision boundaries motivation for non-linear transformation 在线性的 logistic 回归中，hw(x)h_w(x)hw(x) 大于 0.5 时认为是，小于 0.5 时认为不是 有的时候数据分布不适合使用逻辑回归模型（比如二维平面上一类包住了另一类） 简单采用 adding polynomial terms 的方法并不合适，需要泛化性更强的方法。 解决办法：神经网络 universal approximation theorem 用简单的台阶函数去拟合（？） Neural networks 人工神经网络 algorithm that try to mimic the brain SOTA AlexNet: bid data & GPUs perform well on many tasks artificial neurons aka perceptron y=1 if ∑i=1nwixi−θ≥0y=1\ if\ \sum_{i=1}^nw_ix_i-\theta\ge0y=1 if ∑i=1nwi ...
算法博弈论 W37 Myerson's lemma
The most important course in AGT. Review Auction Sponsored search auction’s Goals DSIC dominant strategies, individual rationality. Social welfare maximization. Simplicity (w. r. t. complexity) design of single parameter mechanisms’ Goals: assuming participants report true preferences, maximize the social welfare incentives to the participants to report their true preferences. Myerson’s lemma Single Parameter environments env setup: n participants participant i has a non-negative private ...
