All posts


2016.10.15 Hydrogen energy levels: an algebraic derivation   [Quantum mechanics]
2016.09.16 Earth's rotation and the surface of the ocean   [Mechanics]
2015.10.14 Elastic forces on a rubber band   [Mechanics]
2015.04.22 Water surface on a rotating bucket   [Mechanics]
2014.11.26 Convert between Fahrenheit and Celsius the easy way   [Thermodynamics]
2014.10.17 Non-inertial frames of reference   [Mechanics]
2014.09.19 A proof of Earnshaw's theorem   [Electromagnetism]
2014.05.17 The double pendulum: Hamiltonian formulation   [Mechanics]
2014.02.28 The double pendulum: Lagrangian formulation   [Mechanics]
2014.02.11 Energy at your fingertips: $E = mc^2$   [Relativity]
2013.12.30 Can the electron be found inside the nucleus?   [Quantum mechanics]
2013.12.24 Funnel: how long does the fluid take to go through?   [Fluid dynamics]
2013.11.29 Can we travel to infinity in a finite amount of time?   [Mechanics]
2013.11.26 Electric field at the center of a polygon: symmetry!   [Electromagnetism]
2013.11.23 Uniform circular motion: a mechanics problem   [Mechanics]
2013.11.16 Uniform circular motion: a kinematics problem   [Kinematics]
2013.11.10 Do black holes exist in Newtonian physics?   [Gravitation]


2017.07.12 The intersection area of two circles   [Geometry]
2016.09.23 An easy derivation of 3D rotation matrices   [Linear algebra]
2016.01.15 Surface normals and linear transformations   [Linear algebra]
2015.11.14 An interpretation of the Lagrange multipliers method   [Calculus]
2014.05.21 How many coin flips until you get a head?   [Statistics and probability]
2014.05.01 The Fibonacci sequence and the golden ratio   [Real analysis]
2014.02.09 Matrix compression: the singular value decomposition   [Linear algebra]
2013.12.16 The birthday paradox   [Statistics and probability]
2013.11.12 How much can $i^i$ buy?   [Complex numbers]
2013.10.13 Bayes' theorem: a strange example   [Statistics and probability]
2013.10.12 A proof of Bayes' theorem   [Statistics and probability]

Computer science

2017.10.01 Run-time limits of comparison-based sorting algorithms   [Algorithms]
2017.09.01 The DFT of an image: phase vs. magnitude   [Digital signal processing]
2017.02.28 Solving Sudoku puzzles using linear programming   [Linear programming]
2015.12.01 The set of languages over {0,1} is not countable   [Automata theory]
2015.07.26 Numerically stable computation of arithmetic means   [Numerical methods]
2015.07.19 Denoising data without using fitting functions   [Numerical methods]
2015.04.05 Lossless data compression with Huffman's algorithm   [Algorithms]
2014.11.13 Detecting cycles on undirected graphs   [Algorithms]
2014.06.29 Binary search: an easy but tricky algorithm   [Algorithms]
2014.05.12 Is German harder than English?   [Natural language processing]
2014.04.13 Computing the closest point on a segment to a point   [Computational geometry]
2014.04.11 Computing the closest point on a line to a point   [Computational geometry]
2014.03.27 Integrating polynomials over polygonal domains in 2D   [Numerical methods]
2014.03.17 Relational algebra: obtaining the largest value   [Relational algebra]
2014.03.07 Image compression: the singular value decomposition   [Numerical methods]
2014.01.01 Integrating polynomials over polygonal curves in 2D   [Numerical methods]
2013.10.27 Escaping from the police: a brute-force solver   [Algorithms]


2020.08.19 How to improve Signal Desktop's usability under Firejail   [Security]
2017.08.09 How to fix broken MathJax fonts on Linux   [General]
2016.11.25 Separating iPhone photos and videos by date on Linux   [General]
2015.11.12 Negating globbing patterns in Bash   [Shell]
2015.11.09 Interpreting the output of lspci   [Peripherals]
2015.10.15 Changing volume on PulseAudio via command line   [Shell]
2015.07.24 Extracting a host's network traffic from a pcap file   [General]
2015.01.19 Fixing bmake to compile dynamic libraries on Linux   [General]
2014.12.30 Getting and interpreting routing table information   [Networking]
2014.10.11 Getting CPU architecture information with lscpu   [Processing]
2014.09.18 Redirecting output from stderr to stdout   [Shell]
2014.09.07 Setting the CPU affinity of a process   [Processing]
2014.06.15 Dynamic libraries and ldconfig   [Libraries]
2014.04.27 A better way to list partitions and mounting points   [Storage]
2014.04.16 Using a Brother DCP-7055 on Linux   [Peripherals]
2014.04.09 Performance of cryptographic algorithms in OpenSSL   [Security]
2014.03.31 Executing commands for a specific amount of time   [Processing]
2014.03.29 Specifying SSH connection parameters manually   [Security]
2014.02.15 Listing all files with a set of possible extensions   [Shell]
2014.02.07 Monitoring data transfers through pipes   [Shell]
2014.01.06 Changing a network interface's MAC address   [Networking]
2013.12.23 How to disable all USB devices from a host controller   [Peripherals]
2013.12.19 Interpreting the output of lsusb   [Peripherals]
2013.12.09 Extending partitions via command line   [Storage]
2013.12.08 How to create a Debian image for an Alix board   [Installation]
2013.11.30 Resizing images via command line   [Shell]
2013.11.27 Improve your SSH experience: use an ssh config file   [Security]
2013.11.26 Capturing packets on wireshark as a normal user   [Networking]
2013.11.24 How to concatenate (join) PDF files   [General]
2013.11.24 Disabling the Network Manager   [Networking]


2017.10.22 Asynchronous programming with promises in JavaScript   [JavaScript]
2017.08.23 Determining types deduced by the compiler in C++   [C/C++]
2017.08.07 How std::move breaks return value optimization   [C/C++]
2017.04.01 The nature of the "this" pointer in C++   [C/C++]
2017.03.07 How are virtual function table pointers initialized?   [C/C++]
2017.02.11 Avoid using floating-point numbers as hash table keys   [General]
2017.02.07 Exploring the C++ type system with std::is_same   [C/C++]
2016.11.29 An implementation model for lambda functions in C++   [C/C++]
2016.11.22 Function arguments vs. function parameters in C/C++   [C/C++]
2016.09.19 Computing permutations of sequences in C++   [C/C++]
2016.09.02 Sorting C++ arrays of C-style strings   [C/C++]
2016.08.14 C++ solutions: Cracking the Coding Interview, 4th ed.   [C/C++]
2016.01.23 Shifting calendar time values on a struct tm   [C/C++]
2016.01.01 Sorting in less than $O(n\log n)$ time   [General]
2015.12.27 Checking if an IP belongs to a subnetwork in Python   [Python]
2015.12.14 So what the heck is a char, anyway?   [C/C++]
2015.11.23 Obtaining C/C++ integer sizes and ranges on Linux   [C/C++]
2015.11.19 Generating random numbers in C++   [C/C++]
2015.09.18 Writing into binary files in Python   [Python]
2015.09.07 Working with max- and min-heaps in C++, part II   [C/C++]
2015.08.30 Working with max- and min-heaps in C++, part I   [C/C++]
2015.04.09 Pausing an R script: a generic pause function   [R]
2014.12.23 Generating bitmask permutations in Python   [Python]
2014.09.09 Adding elements to std::deque: a nasty surprise   [C/C++]
2014.06.25 Storing DNA data efficiently in C/C++   [C/C++]
2014.02.05 A new project: freeAML   [C/C++]
2013.12.17 How hard is it to get a git hash collision?   [Git]
2013.11.09 How to backport changes to renamed files using git   [Git]
2013.10.22 Converter between ASCII and hexadecimal   [General]


2019.07.05 Generating maps with customizable markers   [Maps]
2017.01.06 NMEA Generator: A drawing tool for creating GPS logs   [Maps]
2015.11.27 An easy-to-use IP geolocation server   [Geolocation]
2015.10.05 The complexity of feature-rich systems   [General]
2015.04.25 Dealing with iptables errors on a Raspberry Pi   [Raspberry Pi]
2014.01.04 How much power does a Raspberry Pi consume?   [Raspberry Pi]
2013.11.05 IPv6 address space: how large is it?   [IPv6]