evilkalla's New Writeups

What engineering textbooks should be like (idea)

2007-05-14T21:52:56Z

I just finished writing a engineering textbook, in the area of applied electromagnetics, specifically the Method of Moments. One of the key motivations was the need for a book with recent, up-to-date information in the field. However, my primary goal with this book was to alleviate problems I saw with other books in the field (as well as many journal papers): Many authors just don't understand or care about What Engineering Textbooks Should Be Like.

Having read through many good (and bad) engineering books, I'd like to first expand upon several points made by Born2rule, as well as add my own.

Key Points for the Design of Good Engineering Textbooks

1. Standardized Variables: Most authors do a fair job at this throughout their own work, however if drawing upon another reference, the author should do their best to rewrite and integrate the equations using their own notation if possible. It confuses the student when different variables are used for the

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Ghosts 'n' Goblins (thing)

2005-07-06T22:00:41Z

The version of Ghosts 'n' Goblins for the Nintendo NES is probably the hardest and most frustrating platform game ever devised. I'm sure that the Capcom game designers are still getting a big hoot out of people that play this game due to its super high difficulty. I think this has to do with the nature of platform games, usually designed so as to cause the player to take damage from touching enemies or enemy fire. This is in conflict with the unforgiving "two touches and you're out" mentality of a game that's, when compared to a game of similar mechanics such as Super Mario Bros, just really hard to start with. Adding further insult to injury, you must make it through to the end of each zone before your progress "is saved" and you can continue on from that point. The result is, in my opinion, a game that is so far past other platform games in difficulty as to render it ridiculous and comical.

platform game (idea)

2005-07-06T18:46:34Z

The Platform Game is a concept common to many old school video games. In such a game, the world is generally composed of platforms of varying widths and heights. The player typically moves between these platforms by running, jumping, climbing ladders, or through others devices such as ramps or springboards. The gameplay centers around attempting to reach the end of the level by moving between platforms, while eliminating or avoiding enemies or other hazards that populate the level. Gameplay skill is tied to the ability to time jumps between moving platforms, performing accurate running/jumping combos and shooting or avoiding enemies while doing so.

Platform games often involve a common design paradigms known as forced scrolling, where the screen can be scrolled in only the "forward" direction and the player cannot return in the direction they came from. In forced scrolling, platforms that have disappeared off screen are gone and cannot be returned to. In vertically…

Fast Multipole Method (idea)

2005-04-14T22:20:44Z

The N-Body Problem is well known in the scientific community. Succinctly, this involves computing the gravitational potential amongst N masses. Obviously, when the number N grows to be large (thousands, millions), the pairwise computation time grows as N*N.

When N is greatly large, it may be extremely time consuming or impossible to perform such a calculation. The Fast Multipole Method, likely one of the most important algorithms invented in the 20th century, alleviates this problem by presenting an approximate, though error-controllable, method of solving such a problem in O(N) time.

The basic idea behind the FMM is to expand the equation describing the gravitation potential of a point into a set of wavefunctions. Combining the wavefunctions of a pair of source and receive points yields the potential of the 2-mass system.

As wavefunctions must be truncated numerically after some number of modes (to make it numerically tractable), the resulting expression…

What it's like to be free of the FBI (idea)

2005-03-16T18:49:04Z

In case you've been waiting for the conclusion to this story, or What it's like to be free of the FBI.

I learned that my friend Bill is no longer under FBI investigation, though he says that he wonders whether his email is still being sniffed and his website watched by the spooks. He says that sometime last year, about three years after the raid, the special agent that conducted the raid called him on the phone one day out of the blue. The agent told him that the U. S. attorney (whoever this was, Bill has no idea) had decided not to file any charges against him. I suppose this is the way the Feds say they couldn't show you committed any crime. The agent said that his confiscated property would be returned to him soon and for him to provide a shipping address. With that, the phone call ended.

Bill says his belongings showed up about two months later, in three very large cardboard boxes with a return address label reading Department of Justice. Inside one of the…

wastegate (thing)

2005-03-15T20:34:20Z

The wastegate is an integral part of any turbocharger system. It is a device that allows the boost control system to regulate the amount of boost pressure developed by the turbocharger at any particular time.

Most turbochargers utilize separate compressor and turbine housings. The hot exhaust gases from the motor are diverted into the turbine housing and pass through the turbine blades, causing the compressor blades to spin. This in turn creates boost, creating more exhaust gas, and so on. This is a system that must be regulated to provide a constant amount of boost versus engine speed.

To control the amount of boost, a device called a wastegate is employed. The concept is to simply divert or bleed off a certain amount of exhaust gas around the turbine blades and through a secondary path into the exhaust pipe. A typical wastegate comprises a spring-loaded valve connected to manifold pressure. When the boost pressure reaches that matched by the spring, the valve opens…