Slashdot is powered by your submissions, so send in your scoop


Forgot your password?

Comment Re:Saturation (Score 1) 589

... With directional antennas, it is much harder to jam them in the air, as you can filter out any signals at a little above the drone's altitude and below. So, you'd have to be ABOVE the drone to jam GPS signals. This limits the available platforms to electronic warfare aircraft, but with a movable directional antenna, even these signals could be filtered out without much difficulty....

Wow. You have decided that electronic warfare doesn't really work at all, since an incredibly weak signal (10^-16 watts per square meter) can be detected against a 200 watt jammer directly overhead "without much difficulty". Electronic warfare experts everywhere will be amazed. The U.S. Navy only has the best electronic warfare planes in the world.

First off GPS antennas detect signals from satellites in different parts of the sky - they are non-directional (or else have a very small gain since they don't need to look down). Second, the jamming signal strength will be on the order of 100 billion times stronger than the GPS signal. Only a gain of 110 db will overcome this jamming signal, and the highest gain antenna in the world in the 305m Arecibo radiotelescope with a gain of only 70 db.

This also means that the supposed telecomm link to the army of controllers via satellite (must be geosynch to stay in position for hours) cannot be maintained. A high gain antenna would work here, but a 60 cm satellite dish only has a gain of about 35 db, meaning the jamming signal will be 10 to 100 million times stronger.

10,000 drones churn around completely unguided whenever they come within miles of the ships, while any that blunder into an intercept trajectory get blasted with 100% success rate. Number of drones hitting ships: zero.


Comment Re:Odd discussion (Score 1) 589

... What it all comes down to then is, how far is the US willing to push China, and risk a carrier battle group? The missile raises the stakes of pushing China; doesn't mean we wouldn't win in the long run, but the cost is now a lot higher and therefore changes are diplomatic calculus towards China.


But you are missing the real value of the defense system. The chances of China really committing an act of war against the U.S. (firing on an aircraft carrier) is very, very slim. Their missile capability is a rhetorical or psychological threat, to gain the upper hand in diplomatic or geopolitical situations. U.S. defensive weapons neutralize that leverage. The U.S. simply asserts that the Chinese attack would fail and the only way China can prove that it would succeed and is not a "paper tiger" is to begin a shooting war.

Comment Re:Saturation (Score 1) 589

You aren't appreciating just how good modern defensive armaments really are, and how hard it is to destroy an aircraft carrier. And you are overestimating what a really cheap drone can do.

Lets look at the drone. If you want several thousand of them (lets say 4000) "cheaply" then you are spending, what?, $1.1 billion on an equivalent of a $275,000 plane - like a Cessna 172. Cruise speed 140 mph - this is only 4 times faster the ships; its never exceed speed is 188 MPH, total load (including fuel) 750 lb. There are cheaper cars that drive faster. And that $1.1 billion is not exactly chickenfeed.

In the slow crawl out to engage the fleet (3 hours to hit it 420 miles out) the fleet can relocate 100 miles. Makes a dense coordinated attack impossible even if you can track the fleet in real time.

The Phalanx CIWS (Close In Weapon System) that every U.S. combat ship carries is designed to shoot down missiles up to 10 times faster with a much smaller profile with high reliability. The Phalanx success against "soft ball" targets such as you propose is essentially perfect. A carrier strike group deploys at least 8 of these on four ships that can provide mutual support and together can engage 40 targets a minute indefinitely or 200 targets all at once. Of course if this threat was known to exist, they can double up on supporting combat ships if needed for additional Phalanxes, perhaps to double this engagement capacity. And then there is that air wing that can surge enough fire power during this period to engage roughly 1000 targets.

So the air wing gets to thin out any close clumps of targets far out from the fleet so that the CIWS crews can watch their system clean up the rest. Since there is enough time for up 25 CIWS engagements for each target (more if the ships are staggered) there is no chance that even one would reach a ship.

And then there is the ability for the group to lay down a smoke curtain - an ancient tactic. It still works against cameras, but not against the radar-guided defensive weapons.

An accident on the USS Forrestal during the Vietnam War led to nine bombs exploding on-board, the ship returned to service nine months later. The current Nimitz Class aircraft carrier is two-thirds larger and even harder to sink.

This proposal is not unusual to hear from people unfamiliar with the effort put into defending ships.

Comment Re:Cost per watt (Score 1) 177

... Even if we figure out how to make solar cells out of newspaper .. the cost of battery/storage for overnight will keep it's cost above that of coal.....

Red herring. Widespread use of solar power does not require any batteries anywhere. It does not need to simulate the behavior of base load plants or replace them (nuclear plants are the ideal base load plant). Solar power is produced during the highest demand period, when electricity production costs are highest (due to peaking plants coming online). Modern combined cycle natural gas plants can vary their output by 50% or so, and can shutdown/startup in half an hour. Many hydro plants can throttle power as well. These will be major parts of any national power grid for a long time and can provide any load balancing needed.

The current trendline brings PV down to the price of coal in just 5 years or so.

Renewable energy nay-sayers on /. seem quite out of touch from what is happening in the world of power production. In about 10 years wind power will surpass hydropower in production, and about two years after that so will solar power. At that point some 40% of the world's entire electricity production will be from these 3 sources, with renewable all together about half of the total.

Comment Re:"continue to search for and find other deposits (Score 3, Informative) 100

Uhm why not just put the Thorium back into the mine, where it came from?

That is often impossible in an active mine, and in a strip mining situation there is no "mine" to put it into.

By its nature mining takes solid consolidated rock in which nasty materials are locked up (which is why they are there to be found in concentrated form) and turns it into powder from which is now easily leached or transported by water and wind. It is possible to find ways to secure the tails, but that costs money and drives up prices (making the product less competitive) or cuts into profits, both of which mining companies hate. Only strict outside (usually government) oversight keeps mining companies from turning most every mine site into a leaky, ugly toxic waste dump.

Comment Re:Rare Earths (Score 2) 100

the interests that control the USG are against the development of thorium-cycle reactors. And the USG will kill people to see to it that thorium-cycle reactors aren't available on a commercial scale anytime soon.

Which is why the U.S. is active in the international Generation IV reactor research effort, that includes thorium powered designs?

Comment Re:Kuhn is not everything (Score 3, Insightful) 265

Personally, I value the popperian hypothesis-falsification paradigm a lot, especially since it fits so nicely with classical statistical hypothesis testing, and I insist on teaching it to students (I am a biologist), but I am well aware of its limitations.

Popper has been very influential since he provides a clear prescriptive model on how to do science, with a well defended philosophical basis.

The problem is that it does not describe very well how science has actually progressed, in the past or the present. You can argue that there is a sub rosa Popperian process unfolding, but science has rarely advanced by applying an explicit Popperian reasoning and experimental approach.

Kuhn was revolutionary in emphasizing the social process of scientific discovery.

Comment Re:I see the problem (Score 2) 265

(And as a biologist, I feel pretty strongly that paradigm shifting applies equally to physics and biology.)

Indeed. One of the striking things about modern science is the how rapidly the biological sciences are advancing - and how quickly fundamentally new understandings about how biological systems have been appearing. From genetics to genomics, we have within the lifetime of one of the original discovers of the structure of DNA (James Watson) gone through several vast shifts in understanding of how DNA works, and what the DNA record shows about the tree of life.

The new kingdoms of life, dramatic changes in understanding of how evolution proceeds, successive revolutions in understanding DNA (multiple levels of regulation still being discovered, the profound importance of inaccurately named "junk" DNA, etc. etc.). The emergence of new paradigms is obscured perhaps by how many there are and how quickly one follows another.

Comment Re:Uruguay Fiber Optic Plan (Score 2) 157

Here in the US we're going to see a 3rd world status in regards to networking by the end of our lifetimes (that is if it's not already that way yet).

No, we are not. People and companies willing to pay for top-quality networking have access to it.

You left of "willing and ABLE to pay". So as long as the rich can get top-quality networking the U.S. is golden? The U.S. is 19th in the world in broadband penetration, and 19th in the world in broadband speed. Can a nation compete economically when it is far behind in the core infrastructure of the 21st Century?

The expectation that rural areas should get equal connectivity at the same cost as urban areas will always keep the average service below the average service in other countries that are willing to pay what it costs.

How dare rural people expect electricity at affordable prices, decent roads like city-folk, mail service, and broadband? Who do the think they are? Real Americans? You would think they were citizens of what claims to be the greatest nation on Earth or something!

Oddly enough those rural people are in deep red state territory, vote heavily Republican, yet the people seem concerned whether they get access to 21st Century technology are those Marxist America-hating Progressives.

And actually U.S. broadband penetration is so poor (22%) most city-dwellers can't get it.

Comment Re:Censored: "secondary market" (Score 2) 338

Citation please? I have never seen any credible source blaming real estate taxes for bursting the bubble, much less pretending that the bubble would otherwise have lasted forever. Bubbles burst because they are unsustainable and they always burst.

In a two year period the price of land in Japan increased 650% (1986-1988). See:

This sort of insane asset value inflation cannot be sustained. The appreciation in real estate amounted to something like $10 trillion (U.S.), then five times Japan's GDP, and almost equal to the GDP of the entire world.

Sorry, taxes are not the root to all evil, and the cause of all ills in the world.

Comment Re:Difficult to understand? (Score 1) 263

Perl is a multi-paradigm language. It doesn't bundle or insist on a particular model - you are free to use whatever model you want.

And herein lies the problem - program maintenance, which is normally counted as 80% of the cost of software life cycle.

Any language that prides itself on having lots of ways of doing any task or operation, and has many programming models to choose from means that when maintaining legacy code, you must asymptotically approach learning all the ways of doing everything, and all the paradigms, often mixed together, because the vanished legions of programmers that came before are the programming equivalent of a million monkeys.

Context dependent interpretation of the meaning of operators combined with operator over-loading creates tremendous problems with reading code others of written with any certainty of correct understanding.

Far too much attention is paid to aspects of tools that making the fun, easier part of programming (writing new code) more fun and easier, while making the long pole in the tent, maintenance, longer and heavier.

The truth is we must deal with middle of the road to lowest denominator programmers and their work constantly, and defenses of languages that they are easily understood when written by gurus (and read by other gurus) is really an indictment not a defense.

I've done a fair amount of APL and Perl programming, rather liked them when writing with them, but am under no illusion that they tend toward comprehensibility or maintainability.

Comment Re:Does not really matter (Score 1) 655

Free market principles are not at all environmentally friendly - there was no move among capitalists to clean up the air, or the water, stop use of environmentally toxic pesticides, eliminate toxic waste dumps, preserve old-growth forest ecosystems, etc., etc., etc. Not until government regulations forced them to change their practices.

Did unregulated capitalism produce good economic outcomes?

For the individual capitalism yes, but the external costs imposed on everyone else was an economic (and health) disaster.

Slashdot Top Deals

If at first you don't succeed, you are running about average.