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Power

Americans Favor Moratorium On New Nuclear Reactors 964

Posted by samzenpus from the not-in-my-backyard dept.
An anonymous reader writes "While a drop in public support for nuclear power would be expected after an incident like the Fukushima reactor crisis, the nuclear disaster in Japan has triggered a much stronger response among Americans. When Japan — the nation that President Obama held up as an example of safe nuclear power being used on a large-scale basis — is unable to effectively control its considerable downside, Americans are understandably leery about the same technology being used even more extensively in this nation. And safety concerns about the existing nuclear plants also deserve serious attention."
Android

Nexus S Beats iPhone 4 In 'Real World' Web Browsing Tests 260

Posted by timothy from the yeah-but-those-are-only-real-world-results dept.
bongey writes "In a series of measured real-world web load tests, the Android-based Nexus S phone spanked the iPhone 4. The Android phone and iPhone 4 median load times were 2.144s and 3.254s respectively. The sample size was 45,000 page loads, across 1000 web sites. It also follows rumors that Apple is intentionally slowing down web apps to make their native apps more favorable."
United Kingdom

Two-Photon Walk a Giant Leap For Quantum Computing 112

Posted by timothy from the stochastically-awesome dept.
ElectricSteve writes "Research conducted at the University of Bristol means a number of quantum computing algorithms may soon be able to execute calculations of a complexity far beyond what today's computers allow us to do. The breakthrough involves the use of a specially designed optical chip to perform what's known as a 'quantum walk' with two particles ... and it suggests the era of quantum computing may be approaching faster than the scientific establishment had predicted. A random walk – a mathematical concept with useful applications in computer science – is the trajectory of an object taking successive steps in a random direction, be it over a line (with only two possible directions) or over a multi-dimensional space. A quantum walk is the same concept, but translated to the world of quantum computing, a field in which randomness plays a central role. Quantum walks form an essential part of many of the algorithms that make this new kind of computation so promising, including search algorithms that will perform exponentially faster than the ones we use today."
NASA

Obama Outlines Bold Space Policy ... But No Moon 455

Posted by timothy from the all-things-to-all-people dept.
The Bad Astronomer writes "In front of a mostly enthusiastic audience at NASA's Kennedy Space Center today, President Obama outlined a bold, new space policy. It's a change from his previous policy; the Constellation rockets are still dead, but a new heavy-lift rocket system is funded. He specifically talked of manned asteroid and Mars missions, but also stated there would be no return to the Moon. This is a major step in the right direction, but still needs some tweaking."

Comment Re:I don't get why... (Score 1) 322

by Bob Hearn (#31791714) Attached to: All the Best Games May Be NP-Hard

The reason that fun games tend to be NP-hard (or harder) is that if a game's "physics" supports interesting constructions requiring complex reasoning to solve, then probably that same physics can be used to build computational gadgets, which is how you show hardness of the generalized version. This quality expresses itself even on small, fixed-size board.

Comment Re:chess and go aren't np-hard, but they are also (Score 5, Informative) 322

by Bob Hearn (#31791308) Attached to: All the Best Games May Be NP-Hard

Chess and Go are actually EXPTIME-complete, even harder than NP-complete problems and PSPACE-complete problems.

In general, one-player games of bounded length (like Flood-It, or Sudoku) tend to be NP-complete; one-player unbounded games (like sliding-block puzzles, or Sokoban) tend to be PSPACE-complete; two-player bounded-length games (like Hex, or Amazons) also tend to be PSPACE-complete, and two-player unbounded games (like Chess, Checkers, and Go) tend to be EXPTIME-complete.

I can't resist here a plug for my book (with Erik Demaine), Games, Puzzles, and Computation, which discusses all these issues in detail. A theme running throughout the book is the same as the view expressed in this paper: most interesting games and puzzles seem to be as hard as their "natural" complexity class, outlined above.

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