Predicate Logic Solving: TPTP vs SMT

Many interesting problems can be presented declaratively using predicate logic. Real life examples are scheduling, logistics, and software and electric circuit verification. That is, the problems are hard and logic provides a way to solve them declaratively. Logic solvers take as input the problem declaration and spit out the solution to the problem. Examples of …

Continue reading ‘Predicate Logic Solving: TPTP vs SMT’ »

Buying the More Expensive Option

After a visit to a bicycle shop I realised that I need to increase my budget. It makes sense to buy the more expensive bike, as it’s more fun, nicer to ride, and I totally need the fancy features, right? With this premise I was happy to find Olof Hoverfält‘s post about data-supported decision making. …

Continue reading ‘Buying the More Expensive Option’ »

Bayesian Data Analysis of Capacity Factor

Stan is a platform for probabilistic programming. To demonstrate its features I did data analysis of wind energy capacity factor in Finland. Wind energy is feasible in Finland, and we have quite high seasonal variance, so modeling wind data makes an interesting case. This case study presents a Bayesian data analysis process starting from data, …

Continue reading ‘Bayesian Data Analysis of Capacity Factor’ »

Covid-19 False Positives

Lab test false positive rates may feel counter-intuitive. Let’s take a closer look at the state-of-the-art Covid-19 real time PCR test. In Interpreting a covid-19 test result Watson & al., The BJM, May 2020 say that the sensitivity of the test is between 71–98%, and specificity around 95%. The English statistics authority estimates that in …

Continue reading ‘Covid-19 False Positives’ »

Functional Programming in Elm—First Impressions

I built a serverless (progressive) web app ppkk.fi using Elm. Elm is a functional language that compiles to JavaScript so you can make web apps and components to use on web sites. Elm is not an extension to JavaScript or something. Indeed, Elm is a stand-alone programming language with its own compiler and standard libraries. …

Continue reading ‘Functional Programming in Elm—First Impressions’ »

Two Views to Zonings Laws

By co-incidence I read two views on zoning. This resonated with me because I haven’t thought about zoning being optional, that is, that there could exist Western cities without proper zoning. First, about San Francisco: Imagine you’re searching for an apartment in San Francisco – arguably the most harrowing American city in which to do …

Continue reading ‘Two Views to Zonings Laws’ »

Management by Counting on 110% Effort

There’s a massively delayed subway construction project in Espoo, Finland. Based on the public info, the project seems to be a mess of mismanagement. In a discussion regarding the project’s management style, a friend of mine quipped: You know these managers telling their team will get this done by pulling a few all-nighters, or that she’ll be able …

Continue reading ‘Management by Counting on 110% Effort’ »

Freelance Journalists Should Be In Twitter

Last Sunday, I read an interesting article in a print magazine. It’s a rare occasion nowadays so I turned back to the story’s first page to find out the writer’s name. Then I opened the Twitter application on my smartphone. I’ve learned that Twitter is the best way to follow interesting writers, journalists and essayists. You’ll type …

Continue reading ‘Freelance Journalists Should Be In Twitter’ »

Communicating Organization Change – Case Zenefits

Zenefits is a company in trouble. They missed revenue projections, face regulatory charges, and their founder/CEO was forced to resign. How to pick up from here? The new CEO, David Sacks sent an email to all employees. The email was said to be “brilliant”. Let’s see what’s in it. Stripping the email down to essential, it …

Continue reading ‘Communicating Organization Change – Case Zenefits’ »