Category Archives: Engineering

von Neumann Architecture and Bottleneck

We each use computers a great deal (like to write this blog and read this blog) but often have little understanding of how a computer actually works. This post gives some details on the inner workings of your computer.
What Your Computer Does While You Wait

People refer to the bottleneck between CPU and memory as the von Neumann bottleneck. Now, the front side bus bandwidth, ~10GB/s, actually looks decent. At that rate, you could read all of 8GB of system memory in less than one second or read 100 bytes in 10ns. Sadly this throughput is a theoretical maximum (unlike most others in the diagram) and cannot be achieved due to delays in the main RAM circuitry.
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Sadly the southbridge hosts some truly sluggish performers, for even main memory is blazing fast compared to hard drives. Keeping with the office analogy, waiting for a hard drive seek is like leaving the building to roam the earth for one year and three months. This is why so many workloads are dominated by disk I/O and why database performance can drive off a cliff once the in-memory buffers are exhausted. It is also why plentiful RAM (for buffering) and fast hard drives are so important for overall system performance.

Related: Free Harvard Online Course (MP3s) Understanding Computers and the Internet – How Computers Boot Up – The von Neumann Architecture of Computer Systems – Five Scientists Who Made the Modern World (including John von Neumann)

Where are the Senior Female Scientists

Why Are Senior Female Scientists So Heavily Outnumbered by Men? by Anna Kushnir

There is some funny math in the world of academic science. Take my graduate school for example: My class was made up of eight people — seven women and one man, or 7 to 1. He was Snow White and we were the seven dwarves — each with a remarkably appropriate nickname. I was Grumpy, should you be curious to know.

Snow White and at least four of the dwarves have continued on to postdoctoral research jobs. That is a 4 to 3 ratio of women who went on to do a post-doc to those that chose alternate career paths.

Everything is adding up so far, right? Lots of women are around. Lots of science is being done. All is well. The next set of numbers is slightly puzzling, however. That is the ratio of female to male professors in our department, at a well-respected academic institution, is 48 to 7 men to women.
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The proportion of female faculty in her department, 14 percent, is exactly equal to the overall average from the top fifty US chemistry departments.

From her blog: Lab Life: I thought I wanted to be “normal”

The majority of researchers, in my experience, think that stress level, pressure, and time commitments all drop by a factor of ten the moment you step outside of the chemical-smeared walls of a lab. I have come to realize that’s a misconception. It’s just not true. I think that whenever one wants a career instead of a job, time, stress, pressure, and worry are the price to pay.

If all I wanted was a job with a steady income, I am pretty sure I could get it. I would be well-rested and calm, but would I be happy? Would I be alright staying put where I am, with nothing pushing me to reach the next step or rise to the next level? I don’t think so.

I have heard the words ‘ambition’ and ‘drive’ described as derogatory, when applied to people. Unfortunately, I think those are apt words to describe me (in addition to ‘tired’ and ‘often occasionally cranky’). It was an important thing for me to understand about myself and come to terms with. It’s just who I am.

Related: A Decade of Progress for Women in Science – Women Working in Science – posts on scientists at work – Women Choosing Other Fields Over Engineering and Math – science internships

Engineers Rule at Honda

Engineers Rule, 2006

Of all the bizarre subsidiaries that big companies can find themselves with, Harmony Agricultural Products, founded and owned by Honda Motor, is one of the strangest. This small company near Marysville, Ohio produces soybeans for tofu. Soybeans? Honda couldn’t brook the sight of the shipping containers that brought parts from Japan to its nearby auto factories returning empty. So Harmony now ships 33,000 pounds of soybeans to Japan.
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Longtime auto analyst John Casesa, who now runs a consulting company, says, “There’s not a company on earth that better understands the culture of engineering.” The strategy has worked thus far. Honda has never had an unprofitable year. It has never had to lay off employees.

I checked and Honda was also profitable in 2007 and 2008 fiscal year (ending in September).

Related: Honda Engineering – Asimo Robot: Running and Climbing Stairs – The Google Way: Give Engineers Room – Google’s Ten Golden Rules

Demystifying the Memristor

Demystifying the memristor

The memristor — short for memory resistor – could make it possible to develop far more energy-efficient computing systems with memories that retain information even after the power is off, so there’s no wait for the system to boot up after turning the computer on. It may even be possible to create systems with some of the pattern-matching abilities of the human brain.
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By providing a mathematical model for the physics of a memristor, the team makes possible for engineers to develop integrated circuit designs that take advantage of its ability to retain information.

“This opens up a whole new door in thinking about how chips could be designed and operated,” Williams says.

Engineers could, for example, develop a new kind of computer memory that would supplement and eventually replace today’s commonly used dynamic random access memory (D-RAM). Computers using conventional D-RAM lack the ability to retain information once they are turned off. When power is restored to a D-RAM-based computer, a slow, energy-consuming “boot-up” process is necessary to retrieve data stored on a magnetic disk required to run the system.

Related: How Computers Boot Up – Nanotechnology Breakthroughs for Computer Chips – Delaying the Flow of Light on a Silicon Chip – Self-assembling Nanotechnology in Chip Manufacturing

Easier Way to Make Coal Cleaner

MIT has an Energy “Manhattan project”. The USA has a huge amount of coal, if we ever can figure out how to make it clean that will be a huge benefit (though I have my doubts we can really make it clean enough). easier way to make coal cleaner

“Our approach — ‘partial capture’ — can get CO2 emissions from coal-burning plants down to emissions levels of natural gas power plants,” said Ashleigh Hildebrand, a graduate student in chemical engineering and the Technology and Policy Program. “Policies such as California’s Emissions Performance Standards could be met by coal plants using partial capture rather than having to rely solely on natural gas, which is increasingly imported and subject to high and volatile prices.”
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The researchers conclude that as a near-term measure, partial capture looks promising. New coal plants with lower CO2 emissions would generate much-needed electricity while also demonstrating carbon capture and providing a setting for testing CO2 storage — steps that will accelerate the large-scale deployment of full capture in the future.

Related: Solar Thermal in Desert, to Beat Coal by 2020 – Electricity Savings – Wind Power Provided Over 1% of Global Electricity in 2007 – Australian Coal Mining Caused Earthquakes

Engineering A Golf Swing

Golf secret not all in the wrists

After decades of research, the world may be closer to the perfect golf swing. University of Surrey engineer Robin Sharp has found the key is not in using full power from the start, but by building up to it quickly.

Surprisingly, the wrists don’t play a critical role in the swing’s outcome, according to the new model. The analysis also shows that while bigger golfers might hit further, it’s not by much. Any golfer will tell you that the idea of swinging harder to hit farther is not as straightforward as it might seem; the new results indicate that how – and when – the power develops is the key to distance.
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Prof Sharp used a computer model first to fit to the swing styles of three professionals whose swings were measured with high-speed photography in 1968: Bernard Hunt, Geoffrey Hunt and Guy Wolstenholme.

The model showed that the club-head speed, and thus drive distance, of these professionals could have been improved by increasing the torque quickly to the maximum value and maintaining it throughout the rest of the swing. It’s a delicate balance, however, and Sunday duffers may find it hard to implement Prof Sharp’s prescription.

The application of science to sports is an interesting area. Previous posts: Science of the High Jump – Sports Engineering @ MIT – Physicist Swimming Revolution – Baseball Pitch Designed in the Lab

Black and Decker Codeless Lawn Mower Review

photo of Black and Decker cordless lawnmower

My old version of this mower just stopped working and the repair guy said it would cost $250 for a new starter, new battery… So I bought a new one: Black & Decker 19-Inch 24-Volt Cordless Electric Mulching Lawn Mower #CMM1200. He said that the new ones were not as well manufactured. I couldn’t imagine how you could make things worse (it is a simple product and just adopting improvement over the years should be really easy).

But, the starter on this model is horrible. You have to tun this incredibly cheap key in a very poorly designed socket. Fails over 80% of the time. The old model started easily essentially every time. The design was just as you would expect, foolproof. Whatever pointy haired boss approved this design needs to go into another line of work.

The ability of the mower to cope with high grass is very poor – much worse than the previous model. I had a good test at first given the time between my mower breaking and getting the new one. Not often an issue, but still not a good thing.

They had a poor indication of the charge left in the battery previously. They now provide no indication of the charge left. It makes you realize that a poor indication was much better than none.

Battery technology has improved a great deal, and that was one of biggest the weaknesses of the last one. Well they seem to have managed to provide worse battery performance after 5 years of improvement in that technology. Pretty sad.

The bag design is much better than the previous model. You have to assemble it yourself but it is much more sturdy and much better designed – you can replace the fabric and keep the frame. The old model the entire things needed to be replaced if the fabric broke. And given the flimsy design mine broke very early on.
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Science, Engineering and Math Fellowships

I work at the American Society for Engineering Education as an Information Technology Program Manager (this blog is not affiliated with ASEE). A large portion of the computer applications I work on are related to the science and engineering fellowships we administer. The fellowship applications are all open now (for certain fields the NSF application deadline is next week). Those fellowships include:

Other scholarships and fellowships (these are not managed by ASEE): Gates Millennium Scholars Program (January 12th deadline) – NASA Graduate Student Researchers (February 1st) – Goldwater Science Scholarships (January 30th)

Related: Science and Engineering Fellowship Applications Open Now – Directory and application advice for science and engineering scholarships and fellowships

Dean Kamen: Stirling Engines

Dean Kamen: part man, part machine

Conceived in Scotland almost 200 years ago, the Stirling [engine] is a marvel of thermo-dynamics that could help to replace the internal combustion engine – in theory it can turn any source of heat into electricity, in silence and with 100 per cent efficiency. But corporations including Phillips, Ford and Nasa have devoted decades of research, and millions of dollars, to developing the engine, and all retired defeated, having failed to find a way of turning the theoretical principles of the engine into a workable everyday application. Kamen, nevertheless, has spent the past 10 years and, he estimates, up to $40 million working on the problem.

Now he and his engineers have built and tested a range of Stirling engines suitable for mass production that can be run on anything from jet fuel to cow dung. The one in the boot of the small blue car is designed to extend its range and constantly recharge its batteries to make a new kind of hybrid vehicle: one fit for the roads of the 21st century. A Stirling-electric hybrid, Kamen tells me, can travel farther and more efficiently than conventional electric cars; it generates enough power to run energy-hungry devices such as heaters and defrosters that are essential for drivers who, unlike those he calls the ‘tofu heads’ of California, must cope with a cold climate; and even using petrol, the engine runs far cleaner than petrol-electric hybrids such as Toyota’s Prius.

However, Kamen confesses, his new creation isn’t quite finished yet: ‘The Stirling engine’s not hooked up. Which really pisses me off.’

But it could work?

‘It will work,’ he says. ‘Trust me.’

Related: R&D Magazine’s 2006 Innovator of the Year – Robotic Prosthetic Arms for People