A Tower of Molten Salt Will Deliver Solar Power After Sunset

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Solar power projects intended to turn solar heat into steam to generate electricity have struggled to compete amid tumbling prices for solar energy from solid-state photovoltaic (PV) panels. But the first commercial-scale implementation of an innovative solar thermal design could turn the tide. Engineered from the ground up to store some of its solar energy, the 110-megawatt plant is nearing completion in the Crescent Dunes near Tonopah, Nev. It aims to simultaneously produce the cheapest solar thermal power and to dispatch that power for up to 10 hours after the setting sun has idled photovoltaics.

Source: A Tower of Molten Salt Will Deliver Solar Power After Sunset – IEEE Spectrum

Quantum Study Suggests ‘Spooky Action’ Is Real.

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The scientists placed two diamonds on opposite sides of the Delft University campus, 1.3 kilometers apart.

Each diamond contained a tiny trap for single electrons, which have a magnetic property called a “spin.” Pulses of microwave and laser energy are then used to entangle and measure the “spin” of the electrons.

Source: Sorry, Einstein. Quantum Study Suggests ‘Spooky Action’ Is Real. – The New York Times

A potential weakness of the experiment, he suggested, is that an electronic system the researchers used to add randomness to their measurement may in fact be predetermined in some subtle way that is not easily detectable, meaning that the outcome might still be predetermined as Einstein believed.

Point-and-shoot weapon stops drones without destroying them

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The tool is a point-and-shoot system, and has a range of some 400 meters. It gains control of the drone, immobilizing it so no remote action can occur. It does so by either disrupting remote control or GPS navigation.

The drone then either lands in the vicinity or flies back to its starting point, and effectively suffers no damage.

Source: Point-and-shoot weapon stops drones without destroying them

NSA in P/poly: The Power of Precomputation

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Diffie-Hellman is the thing where Alice and Bob first agree on a huge prime number p and a number g, then Alice picks a secret a and sends Bob ga (mod p), and Bob picks a secret b and sends Alice gb (mod p), and then Alice and Bob can both compute (ga)b=(gb)a=gab (mod p), but an eavesdropper who’s listening in only knows p, g, ga (mod p), and gb (mod p), and one can plausibly conjecture that it’s hard from those things alone to get gab (mod p). So then Alice and Bob share a secret unknown to the eavesdropper, which they didn’t before, and they can use that secret to start doing cryptography.

Source: Shtetl-Optimized » Blog Archive » NSA in P/poly: The Power of Precomputation

Kilogram conflict resolved at last

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For decades, metrologists have strived to retire ‘Le Grand K’ — the platinum and iridium cylinder that for 126 years has defined the kilogram from a high-security vault outside Paris. Now it looks as if they at last have the data needed to replace the cylinder with a definition based on mathematical constants.

Source: Kilogram conflict resolved at last : Nature News & Comment

If they are proved right, in 2018, Le Grand K will join the metre as a museum piece. “We’ll keep it,” says Davis, “but it won’t be defining anything anymore.”

secmodel_securelevel

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The securelevel mechanism is intended to allow protecting the persistence of code and data on the system, or a subset thereof, from modification, even by the super-user by providing convenient means of “locking down” a system to a degree suited to its environment.

Source: NetBSD 6.1.5 – man page for secmodel_securelevel (netbsd section 9) – Unix & Linux Commands

Highly secure mode may seem Draconian, but is intended as a last line of defence should the super-user account be compromised. Its effects preclude circumvention of file flags by direct modification of a raw disk device, or erasure of a file system by means of newfs(8). Further, it can limit the potential damage of a compromised “firewall” by prohibiting the modification of packet filter rules. Preventing the system clock from being set backwards aids in post-mortem analysis and helps ensure the integrity of logs. Precision timekeeping is not affected because the clock may still be slowed.

On-chip liquid cooling promises revolutionary change

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The technique involves cutting microfluidic channels into the die of FPGA devices, which were chosen for the research and trials because of their flexible configuration and extensive use in the military. Effectively this locates the cooling just microns from the problem, and even allows for the possibility of chip-stacking, which very few devices currently have the room or efficiency to achieve, given the necessity to dissipate heat from a central locus of adjacent chips.

Source: On-chip liquid cooling promises revolutionary change

Edit Distance Reveals Hard Computational Problems

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As far as computer scientists know, the only general-purpose method to find the correct answer to a SAT problem is to try all possible settings of the variables one by one. The amount of time that this exhaustive or “brute-force” approach takes depends on how many variables there are in the formula. As the number of variables increases, the time it takes to search through all the possibilities increases exponentially. To complexity theorists and algorithm designers, this is bad. (Or, technically speaking, hard.)

SETH takes this situation from bad to worse. It implies that finding a better general-purpose algorithm for SAT — even one that only improves on brute-force searching by a small amount — is impossible.

Source: Edit Distance Reveals Hard Computational Problems | Quanta Magazine

The Jocks of Computer Code Do It for the Job Offers

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The Hacker Cup goes much the same way as other sport-coding contests: five puzzles to finish in any order over three hours. Keep the programming as efficient as possible. The cleanest, most accurate code in the fastest time takes first place. A common type of problem might ask for the shortest route between San Francisco and Los Angeles given a number of constraints. Or perhaps the problem is about how to tile a floor in a specific pattern. The questions typically revolve around a well-known algorithm or mathematical structure with a fresh twist. Elite sport coders must figure out the underlying logic quickly and then trust their abilities.

Source: The Jocks of Computer Code Do It for the Job Offers