https://academa.ai/ https://academa.ai/@sina https://academa.ai/@sina/lectures/how-the-world-wide-web-was-born-protocols-hypertext-and-the-browser 2026-08-30T20:13:11.561Z https://academa.ai/media/l/01M1A3F9BWY8VWPJA47WXGZEC4/0/dark/poster.jpg How the World Wide Web Was Born: Protocols, Hypertext, and the Browser Follow one click round the Web: URLs name documents, HTTP fetches them, HTML carries structure, and your browser paints the result. https://academa.ai/media/l/01M1A3F9BWY8VWPJA47WXGZEC4/0/dark/master.m3u8 685 2026-08-30T20:13:11.561Z no no Computer Science https://academa.ai/@sina/lectures/understanding-the-internet-from-first-principles-with-curl 2026-08-30T19:46:10.906Z https://academa.ai/media/l/01M1A1VXTSGXTXG2QW3QGQGPZJ/0/dark/poster.jpg Understanding the Internet from First Principles with cURL Clients, servers, IP addresses, DNS, TCP and HTTP explained from scratch, then made visible on screen with a few curl commands. https://academa.ai/media/l/01M1A1VXTSGXTXG2QW3QGQGPZJ/0/dark/master.m3u8 716 2026-08-30T19:46:10.906Z 1 no no Computer Science https://academa.ai/lectures https://academa.ai/lectures/accumulation-and-rate-of-change 2026-08-30T18:27:02.683Z https://academa.ai/media/l/01M19SMDHN94WKJJVVVHCW5RH5/0/dark/poster.jpg Accumulation and the Two Halves of Calculus Build the accumulation function from a rate graph, discover its slope is the rate, and reach the Fundamental Theorem of Calculus. https://academa.ai/media/l/01M19SMDHN94WKJJVVVHCW5RH5/0/dark/master.m3u8 924 2026-08-30T18:27:02.683Z no no Mathematics https://academa.ai/lectures/alternating-current-phasors-power-factor 2026-08-30T18:18:43.552Z https://academa.ai/media/l/01M19SKQJEB0510J94A510MNEY/0/dark/poster.jpg Alternating Current: Phasors and Power Factor Phasors, impedance and power factor for AC circuits: why current lags, what reactive power costs, and how a capacitor fixes it. https://academa.ai/media/l/01M19SKQJEB0510J94A510MNEY/0/dark/master.m3u8 1152 2026-08-30T18:18:43.552Z no no Engineering https://academa.ai/lectures/backpropagation-is-the-chain-rule-on-a-graph 2026-08-30T18:08:32.858Z https://academa.ai/media/l/01M19SM490A42VBDBX19YTK7SJ/0/dark/poster.jpg Backpropagation by Hand: From Computational Graphs to Matrix Gradients Follow a tiny neural network through exact forward values, scalar chain-rule backpropagation, matrix gradients, and activation-memory costs. https://academa.ai/media/l/01M19SM490A42VBDBX19YTK7SJ/0/dark/master.m3u8 1185 2026-08-30T18:08:32.858Z no no Machine Learning https://academa.ai/lectures/bayes-through-the-medical-test-paradox 2026-08-30T19:36:50.460Z https://academa.ai/media/l/01M19SN0BS3DMTC3DHS3B3RGZN/0/dark/poster.jpg Why a 99% Accurate Test Can Still Be Wrong See how a 99% sensitive and 99% specific test can be wrong for a rare disease, then watch prevalence, accuracy, and retesting change the odds. https://academa.ai/media/l/01M19SN0BS3DMTC3DHS3B3RGZN/0/dark/master.m3u8 706 2026-08-30T19:36:50.460Z no no Statistics https://academa.ai/lectures/bias-variance-and-the-shape-of-overfitting 2026-08-30T18:02:40.933Z https://academa.ai/media/l/01M19SM553ZV5C0HNP3B08A3PV/0/dark/poster.jpg Overfitting Made Visible: Bias, Variance, and the Role of Data See underfitting, overfitting, training and test error, bias, variance, and the stabilizing role of additional data in one visual experiment. https://academa.ai/media/l/01M19SM553ZV5C0HNP3B08A3PV/0/dark/master.m3u8 803 2026-08-30T18:02:40.933Z no no Machine Learning https://academa.ai/lectures/bloom-filters 2026-08-30T17:01:20.638Z https://academa.ai/media/l/01M19SK3W4QJFB6TX2A5JPYD30/0/dark/poster.jpg The Bloom Filter How a Bloom filter tests membership in a few bits per item, why false positives happen, how to pick k, and why deletion is forbidden. https://academa.ai/media/l/01M19SK3W4QJFB6TX2A5JPYD30/0/dark/master.m3u8 854 2026-08-30T17:01:20.638Z no no Computer Science https://academa.ai/lectures/boundary-layer-drag-crisis 2026-08-30T19:44:17.899Z https://academa.ai/media/l/01M19SMR0NYZB0YVT7K3AATKDC/0/dark/poster.jpg Boundary Layers and Drag: From No-Slip to the Drag Crisis Why ideal flow predicts zero drag, how the boundary layer fixes it, and why separation and dimples decide a sphere's drag. https://academa.ai/media/l/01M19SMR0NYZB0YVT7K3AATKDC/0/dark/master.m3u8 1341 2026-08-30T19:44:17.899Z no no Physics https://academa.ai/lectures/central-limit-theorem-by-sampling 2026-08-30T19:06:44.050Z https://academa.ai/media/l/01M19SN16YFY8VFS8S7REB1Q8Q/0/dark/poster.jpg The Central Limit Theorem, Shown by Sampling Watch a skewed population turn into the normal curve: samples of four, a wall of averages, and the sigma over root n law behind every error bar. https://academa.ai/media/l/01M19SN16YFY8VFS8S7REB1Q8Q/0/dark/master.m3u8 628 2026-08-30T19:06:44.050Z no no Statistics https://academa.ai/lectures/clustering-k-means-and-where-it-fails 2026-08-30T17:21:39.514Z https://academa.ai/media/l/01M19SM5WHYPTTMJGRFR6PX1HW/0/dark/poster.jpg K-Means, Its Failure Modes, and Gaussian Mixture Models A practical visual guide to k-means iteration, its key failure modes, soft membership, and Gaussian mixtures with learned covariance. https://academa.ai/media/l/01M19SM5WHYPTTMJGRFR6PX1HW/0/dark/master.m3u8 822 2026-08-30T17:21:39.514Z no no Machine Learning https://academa.ai/lectures/comparative-advantage-gains-from-trade 2026-08-30T17:01:49.311Z https://academa.ai/media/l/01M19SKDV2XQ3YJ11N72FXZ50C/0/dark/poster.jpg Comparative Advantage: Why Both Countries Gain from Trade Why two countries both gain from trade even when one is slower at everything: opportunity cost, specialization and the frontier. https://academa.ai/media/l/01M19SKDV2XQ3YJ11N72FXZ50C/0/dark/master.m3u8 961 2026-08-30T17:01:49.311Z no no Economics https://academa.ai/lectures/complex-multiplication-as-rotation 2026-08-30T18:34:09.757Z https://academa.ai/media/l/01M19SMEBNTPWQEKVVB1FZN5HX/0/dark/poster.jpg Multiplication as Turning Complex numbers as rotation: i as a quarter turn, lengths multiplying while angles add, Euler's formula, and the cube roots of one. https://academa.ai/media/l/01M19SMEBNTPWQEKVVB1FZN5HX/0/dark/master.m3u8 849 2026-08-30T18:34:09.757Z no no Mathematics https://academa.ai/lectures/concentration-on-the-sphere 2026-08-30T18:45:56.901Z https://academa.ai/media/l/01M19SMF9W1E2KJTW1ADDNDETX/0/dark/poster.jpg Concentration of Measure on the Sphere Why nearly all of a high-dimensional sphere lies within a whisker of any equator: Levy's isoperimetric inequality, concentration, and Dvoretzky's theorem. https://academa.ai/media/l/01M19SMF9W1E2KJTW1ADDNDETX/0/dark/master.m3u8 747 2026-08-30T18:45:56.901Z no no Mathematics https://academa.ai/lectures/cournot-duopoly-and-best-responses 2026-08-30T17:40:08.761Z https://academa.ai/media/l/01M19SKEQN6B1CAR8ZCV60HWZ3/0/dark/poster.jpg Cournot Competition: Best-Response Dynamics and the Race to Equilibrium Watch Cournot firms chase best responses to equilibrium, then compare its price with monopoly, competition, and Bertrand pricing. https://academa.ai/media/l/01M19SKEQN6B1CAR8ZCV60HWZ3/0/dark/master.m3u8 1033 2026-08-30T17:40:08.761Z no no Economics https://academa.ai/lectures/decision-trees-and-why-forests-beat-them 2026-08-30T17:19:25.698Z https://academa.ai/media/l/01M19SM6VREA3SRBZH54JYAS21/0/dark/poster.jpg From One Decision Tree to a Random Forest Grow, overfit, and prune one decision tree, then build a random forest and see why averaging decorrelated trees reduces prediction variance. https://academa.ai/media/l/01M19SM6VREA3SRBZH54JYAS21/0/dark/master.m3u8 1199 2026-08-30T17:19:25.698Z 1 no no Machine Learning https://academa.ai/lectures/deriving-keplerian-orbits-from-conservation-laws 2026-08-30T19:31:17.708Z https://academa.ai/media/l/01M19SMS2B3XQYAB1RHD3Y9ZS1/0/dark/poster.jpg Deriving Keplerian Orbits from Conservation Laws Derive equal areas, conic orbits, Kepler's period law, orbital energy classes, and escape speed from conservation laws. https://academa.ai/media/l/01M19SMS2B3XQYAB1RHD3Y9ZS1/0/dark/master.m3u8 1136 2026-08-30T19:31:17.708Z no no Physics https://academa.ai/lectures/deriving-shear-moment-diagrams 2026-08-30T17:45:45.710Z https://academa.ai/media/l/01M19SKRQY3D9FBQEPF3YK19R1/0/dark/poster.jpg Shear and Moment Diagrams from First Principles Cut a beam, take the free body, and derive shear and moment diagrams from equilibrium, then from the two derivatives that govern them. https://academa.ai/media/l/01M19SKRQY3D9FBQEPF3YK19R1/0/dark/master.m3u8 1104 2026-08-30T17:45:45.710Z no no Engineering https://academa.ai/lectures/diffusion-models-learning-to-denoise 2026-08-30T17:50:16.363Z https://academa.ai/media/l/01M19SM7VJQZG1ZXMJJ6TNA6BG/0/dark/poster.jpg Diffusion Models: From Noise to Images Learn how diffusion models add noise, train a supervised noise predictor, reverse the process, and steer images with text guidance. https://academa.ai/media/l/01M19SM7VJQZG1ZXMJJ6TNA6BG/0/dark/master.m3u8 1386 2026-08-30T17:50:16.363Z no no Machine Learning https://academa.ai/lectures/dijkstras-algorithm-a-spreading-frontier 2026-08-30T17:51:39.298Z https://academa.ai/media/l/01M19SK5WAYN7VENA6XFGFDE85/0/dark/poster.jpg Dijkstra's Algorithm as a Spreading Frontier Watch Dijkstra's algorithm as a frontier of settled nodes spreading outward, and see why the greedy choice is provably safe. https://academa.ai/media/l/01M19SK5WAYN7VENA6XFGFDE85/0/dark/master.m3u8 603 2026-08-30T17:51:39.298Z no no Computer Science https://academa.ai/lectures/dimensional-analysis-drag 2026-08-30T17:16:09.773Z https://academa.ai/media/l/01M19SKSKEJ949AVPHCC2S9S8R/0/dark/poster.jpg Why Wind Tunnel Models Work: Dimensional Analysis of Aerodynamic Drag Why a scale model predicts the drag on a real aircraft: count the dimensions, derive Reynolds and the drag coefficient, and see where Mach breaks similarity. https://academa.ai/media/l/01M19SKSKEJ949AVPHCC2S9S8R/0/dark/master.m3u8 1006 2026-08-30T17:16:09.773Z no no Engineering https://academa.ai/lectures/divergence-and-stokes-theorems 2026-08-30T18:29:05.478Z https://academa.ai/media/l/01M19SMG32T0XN96EKPV0068J7/0/dark/poster.jpg Divergence, and the Two Great Theorems Divergence as outward flow, the divergence theorem, and Stokes' theorem, built from one picture and one cancelling argument. https://academa.ai/media/l/01M19SMG32T0XN96EKPV0068J7/0/dark/master.m3u8 571 2026-08-30T18:29:05.478Z 1 no no Mathematics https://academa.ai/lectures/driven-oscillators-resonance-phase-damping-and-quality-factor 2026-08-30T19:20:46.894Z https://academa.ai/media/l/01M19SMT0QFGMD17DKJR5NGVVV/0/dark/poster.jpg Driven Oscillators: Resonance, Phase, Damping, and Quality Factor Watch a live frequency sweep reveal resonance and phase, then connect damping and quality factor to ring-down and tuned structural control. https://academa.ai/media/l/01M19SMT0QFGMD17DKJR5NGVVV/0/dark/master.m3u8 713 2026-08-30T19:20:46.894Z no no Physics https://academa.ai/lectures/edit-distance-dp-derivation 2026-08-30T17:13:06.506Z https://academa.ai/media/l/01M19SK718NZ7C2RPEYKP7ACXD/0/dark/poster.jpg Edit Distance: From Memorization to Derivation Derive the edit distance recurrence, fill its table cell by cell, recover the edits, and count the work plain recursion repeats. https://academa.ai/media/l/01M19SK718NZ7C2RPEYKP7ACXD/0/dark/master.m3u8 968 2026-08-30T17:13:06.506Z no no Computer Science https://academa.ai/lectures/eigenvectors-and-eigenvalues 2026-08-30T18:35:43.127Z https://academa.ai/media/l/01M19SMH2P2GG0DZM9D80NF3DF/0/dark/poster.jpg Eigenvectors and Eigenvalues: The Directions a Matrix Can't Turn Watch a grid stretch and shear, find the arrows that never turn, and compute eigenvalues and eigenvectors of a 2x2 matrix. https://academa.ai/media/l/01M19SMH2P2GG0DZM9D80NF3DF/0/dark/master.m3u8 735 2026-08-30T18:35:43.127Z no no Mathematics https://academa.ai/lectures/entropy-as-twenty-questions 2026-08-30T17:02:48.861Z https://academa.ai/media/l/01M19SK8DRS8REXV7NH21A3VPT/0/dark/poster.jpg From Twenty Questions to Entropy and Huffman Compression Derive entropy from twenty questions, build a Huffman code, compare its length with the limit, and explain when files can compress. https://academa.ai/media/l/01M19SK8DRS8REXV7NH21A3VPT/0/dark/master.m3u8 871 2026-08-30T17:02:48.861Z no no Computer Science https://academa.ai/lectures/euler-buckling-columns 2026-08-30T17:37:58.197Z https://academa.ai/media/l/01M19SKVHQFTPT81B5R7NXSAJM/0/dark/poster.jpg Euler Buckling: Why Slender Columns Fail by Instability Why slender columns buckle: the critical load derived from the deflected shape, effective length from inflection points, and the slenderness limit. https://academa.ai/media/l/01M19SKVHQFTPT81B5R7NXSAJM/0/dark/master.m3u8 1053 2026-08-30T17:37:58.197Z no no Engineering https://academa.ai/lectures/everything-is-stokes-theorem 2026-08-30T18:51:25.545Z https://academa.ai/media/l/01M19SMHWRZ5EHBX73SA31BK4S/0/dark/poster.jpg Everything Is Stokes' Theorem What Stokes' theorem says: the fundamental theorem of calculus, line integrals and Green's theorem are one line, read at three dimensions. https://academa.ai/media/l/01M19SMHWRZ5EHBX73SA31BK4S/0/dark/master.m3u8 755 2026-08-30T18:51:25.545Z no no Mathematics https://academa.ai/lectures/faraday-lenz-and-the-magnet-that-will-not-fall 2026-08-30T19:28:36.491Z https://academa.ai/media/l/01M19SMTVJTH7H8JMEQB9AT0RT/0/dark/poster.jpg Why a Magnet Falls Slowly Through a Copper Pipe See how changing magnetic flux, Lenz's law, and electromagnetic drag make a magnet fall slowly through copper and power train brakes. https://academa.ai/media/l/01M19SMTVJTH7H8JMEQB9AT0RT/0/dark/master.m3u8 594 2026-08-30T19:28:36.491Z no no Physics https://academa.ai/lectures/frequency-response-bode-closed-loop 2026-08-30T18:01:19.856Z https://academa.ai/media/l/01M19SKWT73G15NJ963SJ3EG76/0/dark/poster.jpg Frequency Response: From Poles and Zeros to Stability and Compensation Build Bode magnitude and phase curves from poles and zeros, define gain and phase margin, then see what lag and lead compensators change. https://academa.ai/media/l/01M19SKWT73G15NJ963SJ3EG76/0/dark/master.m3u8 1641 2026-08-30T18:01:19.856Z no no Engineering https://academa.ai/lectures/gauss-law-and-what-flux-is-counting 2026-08-30T19:16:20.270Z https://academa.ai/media/l/01M19SMVN5GEP5BGGS2Y7BQNGW/0/dark/poster.jpg Electric Flux and Gauss’s Law: How Symmetry Reveals Electric Fields Build electric flux and Gauss’s law visually, apply symmetry to spheres, lines and sheets, then explain conductors and lightning shielding. https://academa.ai/media/l/01M19SMVN5GEP5BGGS2Y7BQNGW/0/dark/master.m3u8 1021 2026-08-30T19:16:20.270Z no no Physics https://academa.ai/lectures/gradient-descent-as-hiking-downhill-in-fog 2026-08-30T17:44:23.611Z https://academa.ai/media/l/01M19SM8NVFVNH24AKJS3FXJGQ/0/dark/poster.jpg Gradient Descent: How the Learning Rate Shapes the Journey See how learning rate controls gradient descent, from steady progress to crawling, divergence, narrow-valley zigzags, and momentum. https://academa.ai/media/l/01M19SM8NVFVNH24AKJS3FXJGQ/0/dark/master.m3u8 857 2026-08-30T17:44:23.611Z no no Machine Learning https://academa.ai/lectures/gyroscopic-precession 2026-08-30T19:37:21.350Z https://academa.ai/media/l/01M19SMWC7NNHFH1AME40V7RCR/0/dark/poster.jpg Why a Spinning Top Stays Up: Angular Momentum and Precession See why gravity turns a spinning top sideways, derive its precession rate, and connect the result to a suspended bicycle wheel. https://academa.ai/media/l/01M19SMWC7NNHFH1AME40V7RCR/0/dark/master.m3u8 926 2026-08-30T19:37:21.350Z no no Physics https://academa.ai/lectures/halting-problem-undecidability 2026-08-30T17:07:37.537Z https://academa.ai/media/l/01M19SK9AYK19NKG9DMMFYTY90/0/dark/poster.jpg The Halting Problem Is Undecidable Cantor's diagonal, the table of programs against inputs, and the contrary program that proves no halting decider can exist. https://academa.ai/media/l/01M19SK9AYK19NKG9DMMFYTY90/0/dark/master.m3u8 966 2026-08-30T17:07:37.537Z no no Computer Science https://academa.ai/lectures/inside-kimi-k3-architecture 2026-08-30T17:32:05.648Z https://academa.ai/media/l/01M19SM9DN6ZRW83HRVCWPDBZ2/0/dark/poster.jpg Inside Kimi K3: Architecture of an Open Frontier Model How Kimi K3 works: expert routing, delta attention, attention residuals, and the 2.5x scaling gain behind an open frontier model. https://academa.ai/media/l/01M19SM9DN6ZRW83HRVCWPDBZ2/0/dark/master.m3u8 707 2026-08-30T17:32:05.648Z no no Machine Learning https://academa.ai/lectures/instantaneous-axis-of-rotation 2026-08-30T17:47:26.767Z https://academa.ai/media/l/01M19SKYHMQE5X01K21CCK3QY6/0/dark/poster.jpg Kinematics of a Body: The Instantaneous Axis The rigid-body velocity relation, the instantaneous centre of a rolling wheel, and the screw axis that replaces it in three dimensions. https://academa.ai/media/l/01M19SKYHMQE5X01K21CCK3QY6/0/dark/master.m3u8 478 2026-08-30T17:47:26.767Z 1 no no Engineering https://academa.ai/lectures/least-squares-is-a-projection 2026-08-30T20:05:33.752Z https://academa.ai/media/l/01M19SN22R9ER7AQ7J4QEN1Q9X/0/dark/poster.jpg Linear Regression as Geometry Learn linear regression through residual geometry, orthogonal projection, normal equations, R squared, and nearly parallel predictors. https://academa.ai/media/l/01M19SN22R9ER7AQ7J4QEN1Q9X/0/dark/master.m3u8 1084 2026-08-30T20:05:33.752Z no no Statistics https://academa.ai/lectures/maxflow-mincut-theorem 2026-08-30T17:07:33.434Z https://academa.ai/media/l/01M19SKABXWRQJ3FKQRVH35EQB/0/dark/poster.jpg Maximum Flow Equals Minimum Cut: Proof by Example Max flow equals min cut, worked by hand on one small network: augmenting paths, a residual backward edge, and the cut that certifies the answer. https://academa.ai/media/l/01M19SKABXWRQJ3FKQRVH35EQB/0/dark/master.m3u8 1123 2026-08-30T17:07:33.434Z no no Computer Science https://academa.ai/lectures/monopoly-marginal-revenue-and-price-discrimination 2026-08-30T17:13:18.503Z https://academa.ai/media/l/01M19SKFN0RYCV99HZMTT8CBJP/0/dark/poster.jpg Monopoly, Marginal Revenue, and Price Discrimination Derive monopoly marginal revenue, compare monopoly with competition, and trace welfare under group and perfect price discrimination. https://academa.ai/media/l/01M19SKFN0RYCV99HZMTT8CBJP/0/dark/master.m3u8 922 2026-08-30T17:13:18.503Z no no Economics https://academa.ai/lectures/monty-hall 2026-08-30T19:37:20.308Z https://academa.ai/media/l/01M19SN2TFH4B3CVEE96TC81RY/0/dark/poster.jpg The Monty Hall Problem: Why Switching Wins Fix one door, list every place the car can be, and count. Then watch the advantage vanish when the host stops knowing where the car is. https://academa.ai/media/l/01M19SN2TFH4B3CVEE96TC81RY/0/dark/master.m3u8 544 2026-08-30T19:37:20.308Z no no Statistics https://academa.ai/lectures/pagerank-the-random-surfer 2026-08-30T17:25:45.535Z https://academa.ai/media/l/01M19SKB7NSKN92WWB1RWSY40D/0/dark/poster.jpg How Hyperlinks Become Votes: The PageRank Algorithm Build PageRank from a random surfer on six pages: link matrix, power iteration, damping factor, dangling pages and rank sinks. https://academa.ai/media/l/01M19SKB7NSKN92WWB1RWSY40D/0/dark/master.m3u8 698 2026-08-30T17:25:45.535Z no no Computer Science https://academa.ai/lectures/period-doubling-logistic-map 2026-08-30T18:52:00.094Z https://academa.ai/media/l/01M19SMJV75SAHWXJH10T6NYDB/0/dark/poster.jpg The Logistic Map: From Fixed Points to Chaos via Period-Doubling Watch one population equation lose its fixed point, double through two, four and eight cycles, and slide into chaos. https://academa.ai/media/l/01M19SMJV75SAHWXJH10T6NYDB/0/dark/master.m3u8 1206 2026-08-30T18:52:00.094Z no no Mathematics https://academa.ai/lectures/pigeonhole-principle-boxes 2026-08-30T18:56:40.623Z https://academa.ai/media/l/01M19SMKN4KTWMQ6SFJMBJVQW9/0/dark/poster.jpg The Pigeonhole Principle: Choosing the Boxes State the pigeonhole principle in one line, then watch it prove three things that look nothing like it. The trick is choosing the boxes. https://academa.ai/media/l/01M19SMKN4KTWMQ6SFJMBJVQW9/0/dark/master.m3u8 649 2026-08-30T18:51:41.331Z no no Mathematics https://academa.ai/lectures/planar-truss-method-of-joints 2026-08-30T17:23:58.117Z https://academa.ai/media/l/01M19SM2C33Y3Y89W08TVXEVCE/0/dark/poster.jpg Planar Truss Analysis: Method of Joints Analyse one planar truss by the method of joints: support reactions, joint equilibrium, tension and compression signs, zero force members. https://academa.ai/media/l/01M19SM2C33Y3Y89W08TVXEVCE/0/dark/master.m3u8 920 2026-08-30T17:23:58.117Z no no Engineering https://academa.ai/lectures/poisson-processes-and-waiting-times 2026-08-30T19:36:20.120Z https://academa.ai/media/l/01M19SN3RYH751KWR2FEQ8DMM2/0/dark/poster.jpg Rare Events in Continuous Time: From Poisson Arrivals to Exponential Waiting Times Derive Poisson counts and exponential waiting times from tiny independent intervals, then test their predictions with arrival data. https://academa.ai/media/l/01M19SN3RYH751KWR2FEQ8DMM2/0/dark/master.m3u8 799 2026-08-30T19:36:20.120Z 1 no no Statistics https://academa.ai/lectures/principal-component-analysis-seen-geometrically 2026-08-30T19:25:05.305Z https://academa.ai/media/l/01M19SMA6XJPNB2K36EBGEZ8BZ/0/dark/poster.jpg PCA from Geometric Intuition to Eigenvectors Understand PCA geometrically, connect maximum projected variance to covariance eigenvectors, and use scree plots, reconstruction, and scaling. https://academa.ai/media/l/01M19SMA6XJPNB2K36EBGEZ8BZ/0/dark/master.m3u8 1063 2026-08-30T19:25:05.305Z no no Machine Learning https://academa.ai/lectures/regex-to-automata 2026-08-30T17:01:50.041Z https://academa.ai/media/l/01M19SKC7FQ64TJ1N101W18856/0/dark/poster.jpg Automata Behind Regular Expressions Build the state machine behind a regular expression, run a string through it, determinise it, and meet the two things regexes cannot do. https://academa.ai/media/l/01M19SKC7FQ64TJ1N101W18856/0/dark/master.m3u8 1044 2026-08-30T17:01:50.041Z no no Computer Science https://academa.ai/lectures/rsa-factoring-encryption 2026-08-30T18:56:22.603Z https://academa.ai/media/l/01M19SMMAN9RECNVD91Y1CAWT8/0/dark/poster.jpg Why Factoring Keeps Secrets: RSA Encryption Build RSA from scratch: modular arithmetic, key generation from two primes, and one message encrypted and decrypted by hand. https://academa.ai/media/l/01M19SMMAN9RECNVD91Y1CAWT8/0/dark/master.m3u8 1084 2026-08-30T18:56:22.603Z no no Mathematics https://academa.ai/lectures/second-price-auctions-and-honest-bidding 2026-08-30T17:31:45.261Z https://academa.ai/media/l/01M19SKGD4TS8GXDZ487XDA109/0/dark/poster.jpg Why Truthful Bidding Works—and Why First-Price Bidders Shade See truthful bidding proved by cases, first-price bid shading derived from incentives, and revenue equivalence stated with its assumptions. https://academa.ai/media/l/01M19SKGD4TS8GXDZ487XDA109/0/dark/master.m3u8 764 2026-08-30T17:31:45.261Z no no Economics https://academa.ai/lectures/simpsons-paradox 2026-08-30T19:41:42.973Z https://academa.ai/media/l/01M19SN4TXBZCTASAZNHPKZEMH/0/dark/poster.jpg When Every Subgroup Agrees but the Total Reverses the Result A concrete treatment example reveals Simpson's paradox, shows its unequal-weight geometry, and explains when pooled rates mislead. https://academa.ai/media/l/01M19SN4TXBZCTASAZNHPKZEMH/0/dark/master.m3u8 728 2026-08-30T19:41:42.973Z no no Statistics https://academa.ai/lectures/solving-2-2-games-best-responses-pure-and-mixed-nash-equilibria 2026-08-30T17:58:07.222Z https://academa.ai/media/l/01M19SKHB9T1DD06KMWHD1DGEH/0/dark/poster.jpg Solving 2×2 Games by Hand: Best Responses, Pure Equilibria, and Mixing Solve 2×2 games by hand using payoff matrices, best-response marks, pure Nash equilibria, expected payoffs, and mixed strategies. https://academa.ai/media/l/01M19SKHB9T1DD06KMWHD1DGEH/0/dark/master.m3u8 1407 2026-08-30T17:58:07.222Z no no Economics https://academa.ai/lectures/stokes-theorem-in-practice 2026-08-30T19:02:36.069Z https://academa.ai/media/l/01M19SMN40GHYPV0AD9KPA7TAY/0/dark/poster.jpg Stokes' Theorem in Practice Stokes' theorem on one exam question: swap the walk around the circle for the flux through the disc, and read the normal off the wording. https://academa.ai/media/l/01M19SMN40GHYPV0AD9KPA7TAY/0/dark/master.m3u8 278 2026-08-30T19:02:36.069Z no no Mathematics https://academa.ai/lectures/supply-and-demand-actually-moving 2026-08-30T17:44:04.866Z https://academa.ai/media/l/01M19SKJ3T77ME0FF8J41MSJ55/0/dark/poster.jpg Supply and Demand in Motion: Equilibrium, Shifts, and Movements Along Curves Learn supply, demand, and equilibrium, then see how harvests, tastes, and new competitors shift curves and change market outcomes. https://academa.ai/media/l/01M19SKJ3T77ME0FF8J41MSJ55/0/dark/master.m3u8 854 2026-08-30T17:44:04.866Z no no Economics https://academa.ai/lectures/support-vector-machines-and-the-widest-corridor 2026-08-30T18:14:02.588Z https://academa.ai/media/l/01M19SMB8K84TRSTHNR77SEAJ9/0/dark/poster.jpg Support Vector Machines: Maximum-Margin Separation and the Kernel Trick A visual introduction to maximum-margin classifiers, support vectors, soft margins, nonlinear feature maps, and the kernel trick. https://academa.ai/media/l/01M19SMB8K84TRSTHNR77SEAJ9/0/dark/master.m3u8 963 2026-08-30T18:14:02.588Z no no Machine Learning https://academa.ai/lectures/taylor-sine-convergence-failures 2026-08-30T18:58:16.024Z https://academa.ai/media/l/01M19SMNRY8108JFH4HA4XHFFW/0/dark/poster.jpg Building the Taylor Series: Convergence and Failure Build the Taylor polynomial of sine term by term, then see why the remainder, not the series, makes the equals sign true. https://academa.ai/media/l/01M19SMNRY8108JFH4HA4XHFFW/0/dark/master.m3u8 965 2026-08-30T18:58:16.024Z no no Mathematics https://academa.ai/lectures/the-birthday-paradox 2026-08-30T19:42:03.116Z https://academa.ai/media/l/01M19SN5J07W9X9Y34F1ARM4PG/0/dark/poster.jpg Why 23 People Make a Shared Birthday Likely A visual explanation of why 23 people cross 50%, why one fixed birthday needs 253 others, and how the same logic predicts hash collisions. https://academa.ai/media/l/01M19SN5J07W9X9Y34F1ARM4PG/0/dark/master.m3u8 589 2026-08-30T19:42:03.116Z no no Statistics https://academa.ai/lectures/the-bootstrap 2026-08-30T19:47:02.467Z https://academa.ai/media/l/01M19SN696VJA7VF8W5CFEV8XG/0/dark/poster.jpg The Bootstrap: Measuring How Much Your Estimate Could Have Wobbled Learn bootstrap resampling through the mean and median, then see its assumptions, interpretation, and classic failure for sample maxima. https://academa.ai/media/l/01M19SN696VJA7VF8W5CFEV8XG/0/dark/master.m3u8 1018 2026-08-30T19:47:02.467Z 1 no no Statistics https://academa.ai/lectures/the-brachistochrone 2026-08-30T19:31:09.041Z https://academa.ai/media/l/01M19SMX5FRR046MNPXTRKEBWC/0/dark/poster.jpg The Fastest Slide: Why the Cycloid Beats the Straight Line Race three slides, derive the brachistochrone by calculus of variations, and see why every release height on a cycloid shares one arrival time. https://academa.ai/media/l/01M19SMX5FRR046MNPXTRKEBWC/0/dark/master.m3u8 680 2026-08-30T19:31:09.041Z no no Physics https://academa.ai/lectures/the-centres-of-a-triangle 2026-08-30T19:13:48.228Z https://academa.ai/media/l/01M19SMPH9NKJ412S500FZYXXC/0/dark/poster.jpg The Centres of a Triangle Medians, perpendicular bisectors, angle bisectors and altitudes: four rules, four centres, and the straight line three of them share. https://academa.ai/media/l/01M19SMPH9NKJ412S500FZYXXC/0/dark/master.m3u8 337 2026-08-30T19:13:48.228Z no no Mathematics https://academa.ai/lectures/the-market-for-lemons-how-hidden-quality-can-cause-a-market-collapse 2026-08-30T17:25:08.479Z https://academa.ai/media/l/01M19SKMZAETYCGSXHFW1S8YCA/0/dark/poster.jpg The Market for Lemons: How Hidden Quality Can Make Good Products Disappear A used-car example explains adverse selection, market unraveling, the value of visible quality, and what common repairs actually fix. https://academa.ai/media/l/01M19SKMZAETYCGSXHFW1S8YCA/0/dark/master.m3u8 759 2026-08-30T17:25:08.479Z no no Economics https://academa.ai/lectures/the-method-of-characteristics 2026-08-30T21:11:12.385Z https://academa.ai/media/l/01M19SMQ6KT38XJWRPR0D43Y6M/1/dark/poster.jpg The Method of Characteristics Walk along the right curves and a first-order PDE becomes an ODE: characteristics, the solution f(x - ct), and where shocks come from. https://academa.ai/media/l/01M19SMQ6KT38XJWRPR0D43Y6M/1/dark/master.m3u8 777 2026-08-30T21:11:12.385Z no no Mathematics https://academa.ai/lectures/the-particle-in-a-box 2026-08-30T19:26:17.340Z https://academa.ai/media/l/01M19SMXVNJ5TE7JEKQ8DYTPWG/0/dark/poster.jpg Why Energy Is Quantised: From Standing Waves to Coloured Molecules Why confined waves admit discrete energies, how box size controls spacing, and how the same model explains trends in conjugated dye colours. https://academa.ai/media/l/01M19SMXVNJ5TE7JEKQ8DYTPWG/0/dark/master.m3u8 801 2026-08-30T19:26:17.340Z no no Physics https://academa.ai/lectures/the-transformer-from-recurrence-failure-to-attention 2026-08-30T18:23:23.352Z https://academa.ai/media/l/01M19SMCGZ0QEQYK3BW7C6EFS3/0/dark/poster.jpg The Transformer: From Recurrence Failure to Attention Build the Transformer from the failure of recurrence: queries, keys, values, scaled dot-product attention, many heads, and position. https://academa.ai/media/l/01M19SMCGZ0QEQYK3BW7C6EFS3/0/dark/master.m3u8 1301 2026-08-30T18:23:23.352Z no no Machine Learning https://academa.ai/lectures/three-sat-vertex-cover-reduction 2026-08-30T17:09:36.822Z https://academa.ai/media/l/01M19SKCWSVAPG524XAQPNBSWY/0/dark/poster.jpg NP-Completeness and Reduction: From Definitions to the 3-SAT to Vertex Cover Proof P and NP defined by verifiers, then the 3-SAT to Vertex Cover reduction built and argued in both directions on one formula. https://academa.ai/media/l/01M19SKCWSVAPG524XAQPNBSWY/0/dark/master.m3u8 1265 2026-08-30T17:09:36.822Z no no Computer Science https://academa.ai/lectures/time-dilation-from-a-light-clock 2026-08-30T19:34:03.424Z https://academa.ai/media/l/01M19SMYR3E84GZDQVA7WDKGRP/0/dark/poster.jpg Special Relativity: Light Clocks, Spacetime, and the Twin Paradox Derive time dilation and length contraction, understand simultaneity, resolve the twin paradox, and explain atmospheric muons. https://academa.ai/media/l/01M19SMYR3E84GZDQVA7WDKGRP/0/dark/master.m3u8 1140 2026-08-30T19:34:03.424Z no no Physics https://academa.ai/lectures/torsion-shafts 2026-08-30T17:30:22.537Z https://academa.ai/media/l/01M19SM35EGT0TGJ4CHH8GHCK1/0/dark/poster.jpg Torsion: From Geometry to Shaft Design How twisting a round shaft gives shear strain linear in radius, the torque integral, the polar moment of area, and why drive shafts are tubes. https://academa.ai/media/l/01M19SM35EGT0TGJ4CHH8GHCK1/0/dark/master.m3u8 764 2026-08-30T17:30:22.537Z no no Engineering https://academa.ai/lectures/who-really-pays-a-tax 2026-08-30T17:20:11.791Z https://academa.ai/media/l/01M19SKNPZBTDRABZAG9RJ3MMF/0/dark/poster.jpg Who Really Bears a Tax? Tax Incidence, Elasticity, and Deadweight Loss See how elasticities split a per-unit tax, why remittance rules do not decide incidence, and why deadweight loss rises with tax squared. https://academa.ai/media/l/01M19SKNPZBTDRABZAG9RJ3MMF/0/dark/master.m3u8 829 2026-08-30T17:20:11.791Z no no Economics https://academa.ai/lectures/why-the-rainbow-sits-at-42-degrees 2026-08-30T19:44:08.250Z https://academa.ai/media/l/01M19SMZGZS1PFAJJ4VN0GQKDZ/0/dark/poster.jpg Why the Rainbow Sits at 42 Degrees Derive the rainbow's 42 degree angle from one raindrop: refraction, one internal reflection, and the minimum of the deviation curve. https://academa.ai/media/l/01M19SMZGZS1PFAJJ4VN0GQKDZ/0/dark/master.m3u8 548 2026-08-30T19:44:08.250Z no no Physics https://academa.ai/pricing https://academa.ai/privacy https://academa.ai/subjects/computer-science https://academa.ai/subjects/economics https://academa.ai/subjects/engineering https://academa.ai/subjects/machine-learning https://academa.ai/subjects/mathematics https://academa.ai/subjects/physics https://academa.ai/subjects/statistics https://academa.ai/team https://academa.ai/terms