William John Holden

Web Applications

• All paths between two vertices
• Relational algebra
• Transitive Closures for Functional Dependencies
• Rack elevation diagrams
• Birthday paradox generator
• Binary Search over a Non-Uniform Distribution using the Geometric Mean
• Monty Hall Problem
• Memory Game
• Whitespace-separated values matrix to CSV vector
• Scheduling with Local Search
• Editing Distance Clusters
• Generic Bisection Solver
• Checklist generator
• Configuration builder for routers and switches in JavaScript
• Shortest-path solver with Dijkstra's algorithm, implemented in JavaScript
• Tic-Tac-Toe solver for Z3.
• Key chain generator for Cisco devices
• Triangulate an unknown point in ℝ² (click on the square)
• CommSync II output interpretter
• lsdb.js, an OSPF Link State Database Parser
• 2D Affine Transformations in CSS
• Priority Queue in JavaScript
• Big Numbers in JavaScript
• Simple Polish Calculator and Lambda Polish Calculator
• Fractal trees in WebGL (finished project)
• Monte Carlo approximation of π
• Megasymbols to Megabits Converter
• DSCP reference from RFC 4594. Source code.
• Convert String to HTML Special Codes
• Demonstration of HTTP (program).
• MGRS Distance and Direction Calculator

Programs

• Sieve of Eratosthenes
• Metronome in Python.
• A generalized form of the matrix product in Julia.
• Compute the (not-necessarily-minimum) spanning tree of a graph using MySQL queries.
• Measure jitter in PowerShell (manifest).
• Basic statistics in PowerShell. The integral is not very accurate.
• Path MTU discovery in PowerShell
• Measure bandwidth in PowerShell
• Editing distance in Julia using bottom-up and top-down (recursive) dynamic programming.
• Multicast Syslog client/sender in PowerShell
• An intentionally-bugged crossword meme generator like those "first three words you see are your reality," only this one contains few or no words. My first-ever Julia program.
• SAT Solver in Java using backtracking. Slow, but passes all AIM test cases of size 50 and 100.
• 5/3/1 table generator
• Connection Map, a Java Swing application to visualize TCP connections through a Cisco ASA using GeoLite2 data created by MaxMind.
• PowerShell module to convert IP addresses to integers and back.
• Dynamic programming solution to a wings menu problem. I've also made a video explanation. Also, here is a Wolfram Cloud application that applies the same algorithm (with disappointingly different results).
• Area Monitor, a Python script that uses PySNMP to scrape the OSPF Link State Database from a router and then render it as a graph using Viz.js.
• Node Monitor, a simple but (somewhat) scalable ICMP poller in Java to monitor large IT deployments.
• Route Monitor, a Java application to visualize routes advertised using RIPv2.
• Pisano Periods in WAV format, inspired by an edX course in Algorithm Design and Techniques and a Numberphile video. The WAV generation library is from Douglas Thain.
• Trie dictionary in C inspired by Robert Pitts.
• Weak RSA. Generates RSA keys with RANDU (a weak PRNG) and discovers common factors.
• Denial of service attack against Hot Standby Router Protocol and a video explanation.
• Polish Calculator for plotting simple functions of two variables.
• How can you print 1 to 100 in Java using no loops and no conditions? Two solutions I came up with use thread pools and reflection.
• Multicast Syslog console server in Java, mostly useful for troubleshooting multicast routing.
• NetViz, a pedagogical animated Swing application for illustrating loop prevention mechanisms used in routing and switching.
• Kruskal's Algorithm (Kruskal.jar) for computing the Minimum Spanning Tree of a graph.
• CopyRunHere, a technique for running show commands on many Cisco routers over SSH.
• Warshall's Algorithm (Warshall.jar) for finding the transitive closure of a relation.
• Power Set (PowerSet.jar) generator for integer sets with an interesting listComparator.
• Set Equality (SetEquality.jar) demonstration.
• Bisection algorithm to approximate a zero for a given function.
• Hello OSPF, a simple C program to send OSPF Hello packets. Old versions.
• RSA Cryptography Standard implemented in Java.
• IPv4 utility to find subnet masks and summary routes.
• 3dadd: "&&'s" the pixels of a bitmap together to produce a 3D .obj geometry that can be imported into Blender. Written in C#.
• Caesar cipher and trivial summation hash in C# for teaching cryptography fundamentals.

Papers

• Reindeer Replacements: Solving a children's logic puzzle with OR-Tools
• Automatic String Classification by Editing Distance
• Analyzing Open Shortest Path First (OSPF) Networks with Neo4j and Cypher
• How to find Gamma in a Power Law Distribution
• Choose and the Combination Formula
• Can you get a better model by interpolating fake data points by averaging? (No, you cannot).
• Linear Modeling in R
• Geometric Mean for Trapezoidal Integration
• Recursive depth to compute the geothmetic meandian (from xkcd) does not depend on the variance, skewness, or kurtosis of the input
• Advent of Code 2020 Day 1 in SQL
• Impressions of R from an Introductory Course on Statistics
• Why don't I know anyone who knows anyone with COVID-19?
• Chosen sequences among linear congruential generators using SAT/SMT solvers: a Valentine's Day card to Mayflor Jamero Holden
• z3 solution to the "which answer in this list is the correct answer to this question" problem.
• Effective Knowledge Management with Microsoft SharePoint
• Side Project Summary 2017-2019
• CSfC with GNS3 Lab Guide
• Matrix tricks (my first Jupyter notebook, yay!)
• I independently discovered Pascal's formula and felt so clever I wrote a whole paper on the combination formula and provide a Python program comparing Pascal's formula and the binomial function, both with dynamic programming.
• My Advent of Code experience using Mathematica.
• Solution to the matching parentheses problem using polynomials in Mathematica.
• My book, a slow work-in-progress (currently) titled Applied Computer Science.
• 90 Degree Rotations for Advent of Code 2017 Day 22.
• Analysis of the associative property of matrix cross products. This stems from my efforts to develop my own linear algebra library in JavaScript for a school project.
• Discrete Math Review
• Calculus Review
• Hackers Cannot Be Mass Produced
• Not my paper, but it was my question: How Many Hosts In An VLAN or IP Subnet and Why?
• Radix Minus One, a useful arithmetic property.
• A Beautiful Proof to a Facebook Math Problem.
• Netsh Command Reference
• Math Tricks for IP Subnetting
• Inverse Fibonacci Formula

Fitness

• 400 meter interval sprint competition
• Soju and Tuba Kettlebell Press Program Review
• CrossFit WOD Generator
• Barbell loads in pounds
• Barbell loads in kilograms
• 5/3/1 daily workouts
• 5/3/1 training cycles in Julia
• 1RM calculator using eight different functions (also in Julia).
• 340×3 equivalent (how many reps r at some weight w to satisfy 1RM[340,3] == 1RM[w,r])
• Month of a mile of lunges each week (video)
• 50 Pull-Ups Every Day for a Month (video)
• A list of bad exercises.
• Pseudorandom workout of the day and month.

Advent of Code

• Advent of Code 2019 in Julia.
• Advent of Code 2020 in Python.
• Advent of Code 2024 in Rust

• One Liners
• Windows Terminal settings.json with Julia, R, Python, and JShell
• putty.reg registry key to make PuTTY the default application for telnet:// links.
• Starter webpage

Qualifications

• CrossFit Level 1 Trainer
• Bachelor of Science in Computer Science, Summa Cum Laude, no. 17A1-8005-W5N8
• Neo4j Certified Professional
• ALGS200x: Algorithmic Design and Techniques
• ALGS201x: Data Structures Fundamentals
• ALGS202x: Graph Algorithms
• ALGS203x: Algorithms for NP-complete Problems
• Cisco Certified Network Associate, no. 5VS0DL2NPC14Q755
• Cisco Certified Network Associate, Routing and Switching, no. 417772847595IPCJ
• Cisco Certified Network Associate, Voice, no. 417772847578BKBM
• Cisco Certified Network Associate, Security, no. 417772847587HMBF
• Cisco Certified Network Professional, Routing and Switching, no. 429834169669HMVL
• CompTIA A+ (2009 edition), no. YEB2NLDKVDV45V55
• CompTIA Network+ (2009 edition), no. 2XBST9GDLLVQ2GHC
• CompTIA Security+ (2008 edition), no. 7NLYWPWJJPE4Q20F
• CompTIA A+ ce, no. K7T3PPBEDLQ1SBQV
• CompTIA Project+, no. K005YRNPCPR4QD9L
• CompTIA Advanced Security Practitioner ce (CASP+), no. 0BRQ33HNGC4EQ2GM
• ITIL Foundation Certificate in IT Service Management, no. 6078064.20691483
• Oracle Certified Professional, Java SE 6 Programmer
• Microsoft Specialist: Windows 7, Configuring, no. 1150290, code wjholden1013454