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Here's an idea for head position tracking hardware: put a bunch of bright balls around the outside of a helmet, and have the person surrounded by a handful of cameras.

Better yet would be the use of tiny gyroscopes like this that provide 6DOF, although this one doesn't. No need for worn optical cues and cameras. There is also this product that has 3DOF, which claims to "have metallic interference virtually eliminated". I presume it is some kind of magnetic tracker that isn't as vulnerable to the weaknesses of normal magnetic motion tracking methods, which I think the grandparent poster is referring to.

The method you are mentioning using bright balls and cameras are optical motion trackers. Magnetic ones have advantages over optical ones. Optical ones have other disadvantages, and don't normally work in real-time, so they wouldn't be viable for head position tracking for virtual reality.

Here's an idea for head position tracking hardware: put a bunch of bright balls around the outside of a helmet, and have the person surrounded by a handful of cameras.

Better yet would be the use of tiny gyroscopes like this that provide 6DOF, although this one doesn't. No need for worn optical cues and cameras. There is also this product that has 3DOF, which claims to "have metallic interference virtually eliminated". I presume it is some kind of magnetic tracker that isn't as vulnerable to the weaknesses of normal magnetic motion tracking methods, which I think the grandparent poster is referring to.

The method you are mentioning using bright balls and cameras are optical motion trackers. Magnetic ones have advantages over optical ones. Optical ones have other disadvantages, and don't normally work in real-time, so they wouldn't be viable for head position tracking for virtual reality.

Here's an idea for head position tracking hardware: put a bunch of bright balls around the outside of a helmet, and have the person surrounded by a handful of cameras.

Better yet would be the use of tiny gyroscopes like this that provide 6DOF, although this one doesn't. No need for worn optical cues and cameras. There is also this product that has 3DOF, which claims to "have metallic interference virtually eliminated". I presume it is some kind of magnetic tracker that isn't as vulnerable to the weaknesses of normal magnetic motion tracking methods, which I think the grandparent poster is referring to.

The method you are mentioning using bright balls and cameras are optical motion trackers. Magnetic ones have advantages over optical ones. Optical ones have other disadvantages, and don't normally work in real-time, so they wouldn't be viable for head position tracking for virtual reality.

http://pao.cnmoc.navy.mil/pao/n_online/archive/vol 22no1/articles/2001.htm

Phalanx Close-In Weapons System

So far, every attempt at refuting the proof of forgery has fallen flat on its face - look at the link to an authentic page of Bush's record claiming the font is "identical" to CBS's PDFs - except the linked record is monospaced using "open" 4s, the CBS memos are proportionally-spaced using closed 4s.

There is a very simple way to end all this, all Bush needs to do is to allow access to his military record, something he has refused to do so far. The only documents that have been allowed out have been edited by the WH and its supporters.

There are plenty of pages out there - and it seems Kerry has released no more than 6% (4th paragraph from the bottom) of his own. There is, however, a simple way to end this controversy: CBS can produce the originals, and/or produce their anonymous "document expert" who allegedly authenticated these documents yet disagrees utterly with the leading authority in the field.

The document's already been compared to one authentic page of Bush's record - and isn't even similar. Why would the microfiche copy show anything different?

Bush refused a direct order to take a medical shortly after random drug testing for pilots was introduced. Those are the facts, deal with them.

Actually the fact is that cocaine testing was introduced by the military in 1980 ("By July 1980 methaqualone was dropped and cocaine was added to the test panel"), and wouldn't be done as part of your annual physical anyway (that would be stupid: give everyone a year's notice of their next drugs test?!). This rather bursts the whole "Bush was avoiding a drugs test" theory.

No. Poster is an idiot.

Any instructions on how to set one of these up?

Hams do this sort of thing all the time (well, broadcasting their location, rather than stalking their girlfriends.)

Here is a list of stations currently broadcasting their coordinates near my house ...

Same info, different site:
http://www.fas.org/irp/world/para/ano.htm

Here's another Saddam-supported group of Marxist terrorists:
http://library.nps.navy.mil/home/tgp/mek.htm

Any thorough War on Terror needed to address Iraq sooner or later.

Same info, different site:
http://www.fas.org/irp/world/para/ano.htm

Here's another Saddam-supported group of Marxist terrorists:
http://library.nps.navy.mil/home/tgp/mek.htm

Any thorough War on Terror needed to address Iraq sooner or later.

Hey, thanks for the idea... I just found some neat videos of sun flares... Check them out here.

http://lasco-www.nrl.navy.mil/daily_mpg/

What's all that about?

To all the game developers reading this thread, here's a link to the open-source game engine
we are developing here at the MOVES Institute in Monterey, CA (of America's Army fame):

http://www.nps.navy.mil/cs/research/vissim/Engine/ enginemain.html

...and the source:
http://sourceforge.net/projects/delta3d

We are shooting for a 1.0 release in December, but the majority of features are already complete.
A number of in-house game-like simluations have already used it with great success. Happy coding!

-chris osborn

1. open standards based, and;
2. secure.

A large selection of imagery with animations and image archives (~48 hours or so) can be had at https://www.nemoc.navy.mil/sat_user.php. Be sure to check out the modis/eos dataset. No password is required for 90% of the site...

Naw. Because the range at which you're seeing a given pressure level is much shorter. As he said, it was to simulate a nuke from a blast perspective. So to study a given level of blast pressure, you could either standoff a given distance from a 5kt blast of HE, or standoff a larger distance from an 8kt nuke.

All sorts of fun stuff has been done to simulate various aspects of nuclear weapons. Operation Sailor Hat was another blast sim, using 500 tons of TNT. When I was blowing stuff up for the Navy, I saw films of this test, from high-speed cameras mounted on a nearby destroyer, and you could see the steel torpedo tubes just ripple like a sheet in the wind when the shockwave hit.

One guy I know worked for a military contractor at one point, trying to simulate the flash effect of a bomb. They came up with a biiig double-barreled cannon. One barrel fired, at supersonic velocities, a big blast of liquid oxygen. The other fire, at supersonic velocities, a big blast of powdered aluminum. I haven't found films of that, but, wow.

Port Chicago in WWII was by all accounts, huge, hundreds of tons of ordnance accidentally detonated. Loss of life was much less, 320 killed with 390 wounded, than the Halifax explosion due to the relative isolation of the docks. Descriptions of the accident and resulting carnage here http://www.history.navy.mil/faqs/faq80-1.htm/

Shameless lifted from Some random page about the Port of Chicago explosion.

On the evening of 17 July 1944, the empty merchant ship SS Quinault Victory was prepared for loading on her maiden voyage. The SS E.A. Bryan, another merchant ship, had just returned from her first voyage and was loading across the platform from Quinault Victory. The holds were packed with high explosive and incendiary bombs, depth charges, and ammunition - 4,606 tons of ammunition in all. There were sixteen rail cars on the pier with another 429 tons. Working in the area were 320 cargo handlers, crewmen and sailors.

At 10:18 p.m., a hollow ring and the sound of splintering wood erupted from the pier, followed by an explosion that ripped apart the night sky. Witnesses said that a brilliant white flash shot into the air, accompanied by a loud, sharp report. A column of smoke billowed from the pier, and fire glowed orange and yellow. Flashing like fireworks, smaller explosions went off in the cloud as it rose. Within six seconds, a deeper explosion erupted as the contents of the E.A. Bryan detonated in one massive explosion. The seismic shock wave was felt as far away as Boulder City, Nevada. The E.A. Bryan and the structures around the pier were completely disintegrated. A pillar of fire and smoke stretched over two miles into the sky above Port Chicago. The largest remaining pieces of the 7,200-ton ship were the size of a suitcase. A plane flying at 9,000 feet reported seeing chunks of white hot metal "as big as a house" flying past. The shattered Quinault Victory was spun into the air. Witnesses reported seeing a 200-foot column on which rode the bow of the ship, its mast still attached. Its remains crashed back into the bay 500 feet away.

All 320 men on duty that night were killed instantly. The blast smashed buildings and rail cars near the pier and damaged every building in Port Chicago. People on the base and in town were sent flying or were sprayed with splinters of glass and other debris. The air filled with the sharp cracks and dull thuds of smouldering metal and unexploded shells as they showered back to earth as far as two miles away. The blast caused damage 48 miles across the Bay in San Francisco.

Who is this? [unrelated to redhead]

I don't know about the fellas on either side, but the lady in the middle looks like Alyssa Milano. She did at least one USO visit in 2003. That was a Navy show, but it mentions ground forces (the Army guys?) and at least we can place her in the area at some point.

You could have a look at APRS. Although many APRS projects are intended to work with Amateur Radio equipment, I think it isn't too difficult to adapt some of them to talk to your cellphone, sending and receiving GPS coordinates by SMS or email.

The US Navy actual does a lot of research of gravity waves, however they are referring to a slightly different definition or nature. Instead they are looking at periodic influences of tides and other aspects of gravity. For example, examining the effects of "gravity waves" on the atmosphere. It also doesn't help that a component of surface waves on the ocean are also called "gravity waves" since these are waves that are working against gravity. A google search shows the stuff does show up in a lot of Navy research documents, and would probably be pretty confusing if it doesn't give enough information to hint it is not the same gravity waves talked about here.

There has been a few popular discussions of gravity wave (in the normal sense) communication, including a short blurb in several magazines that I recently remember referring to a paper about converting electromagnetic waves to gravity waves. I'm skeptical of what is proposed, but it doesn't take too much equipment to test, so I wouldn't be surprised if other people were testing it. Although there is no explicit mentioning of the Navy in any of that I remember.

slide
orbits
Schmidt_02

No.

Actually, Yes.

This is only about the difference between the time it takes for the sun to reach the same point in the sky each day, and the the time it takes for the stars to appear at the same point in the sky. These times differ by the ~4 min. daily.

This is correct. My post explains why this is true. Because the earth revolves around the sun, in addition to rotating on its axis, there is a difference of 1 day/year, which translates to 4 minutes/day. It happens that since the rotation of the earth is in the opposite direction of the earth's orbit, the day is subtracted The sidereal day is shorter, and there are (roughly) 366.25 sidereal days in a year.

Leap year, however, involves the correction for the fact that the solar day is slightly greater than 24 hrs. (only slightly). This requires the leap year to correct for the overage.

I don't even know how leap years get into this. Leap years have nothing to do with the length of the day. They have to do with the length of the year. One year is 365.25 (roughly) days, so every four years we throw in an extra day to make up for that .25. Now, as someone in another irrelavent discussion of leap years mentioned, the real number is 365.2425 solar days, so we don't have leap years on the century unless the year is also divisible by 400. (which is why 2000 was a leap year, but 1900 and 2100 are not.)

No time schemes are based on, nor are concerned with the "astral day" of 23:56, etc.

It's called "Sidereal Time", and astronomers use it all the time, because it's much more convenient for their purposes. Lick Observatory even has a grandfather clock in the hall that runs on Sidereal Time.

Click here to calculate your local apparent Sidereal Time.

Was this US Navy ship by any chance named the USS Eldridge?

This would be useful for a hovering UAV, say like the cypher (now Cypher II aka Dragon Warrior) which could relay the image of the remote target to, conceivably, a sniper/sniper's spotter, or provide GPS coordinates to incoming aircraft for precision bombing using an Ethernet TCP/IP radio network with autorelaying capability. .

There are some pics, operator software screen shots, mpegs and info available to see how this particular vehicle is deployed at the US Navy's Space and Naval Warfare Systems Center, San Diego's Advanced Systems Division Robotics program.

This would be useful for a hovering UAV, say like the cypher (now Cypher II aka Dragon Warrior) which could relay the image of the remote target to, conceivably, a sniper/sniper's spotter, or provide GPS coordinates to incoming aircraft for precision bombing using an Ethernet TCP/IP radio network with autorelaying capability. .

There are some pics, operator software screen shots, mpegs and info available to see how this particular vehicle is deployed at the US Navy's Space and Naval Warfare Systems Center, San Diego's Advanced Systems Division Robotics program.

This would be useful for a hovering UAV, say like the cypher (now Cypher II aka Dragon Warrior) which could relay the image of the remote target to, conceivably, a sniper/sniper's spotter, or provide GPS coordinates to incoming aircraft for precision bombing using an Ethernet TCP/IP radio network with autorelaying capability. .

There are some pics, operator software screen shots, mpegs and info available to see how this particular vehicle is deployed at the US Navy's Space and Naval Warfare Systems Center, San Diego's Advanced Systems Division Robotics program.

This would be useful for a hovering UAV, say like the cypher (now Cypher II aka Dragon Warrior) which could relay the image of the remote target to, conceivably, a sniper/sniper's spotter, or provide GPS coordinates to incoming aircraft for precision bombing using an Ethernet TCP/IP radio network with autorelaying capability. .

There are some pics, operator software screen shots, mpegs and info available to see how this particular vehicle is deployed at the US Navy's Space and Naval Warfare Systems Center, San Diego's Advanced Systems Division Robotics program.

Recently, with the war and all, I've taken more of an interest in military affairs. Lo and behold, the military publishes a lot of magazines and periodicals internally, and many of them are available free online! I like them because they don't have the macho posturing of rags like Soldier of Fortune and other right-wing civillian magazines, and read like professionals writing for other professionals on how to do their job better. Think Wired vs. Linux Journal.

List of DoD magazines
Soldiers - Official army magazine, with full PDF archive.
Airman - Official air force magazine
Marine - Official USMC magazine
Approach - Navael aviaton safety magazine
Ground Warrior - Marine training safety magazine
Infantry magazine - Army infantry magazine, article archive at findarticles.com
Parameters - The U.S. War College's periodical

Soldiers, Airman, and Marine are sort of PR-related publications, so they aren't as interesting. Approach, Ground Warrior and Infantry are written as advice and information sources for their respective professions, so they have more technical detail. I like how they give a view of day-to-day operations in the military, especially training mishaps and other mistakes you don't hear about often. Parameters is a more scholarly magazine that gives a view into what the high-level officers are thinking and planning right now, plus some military history.

They're your tax dollars at work, may as well read them. Better to be an informed citizen than an entertained consumer, especially with the war in Iraq going on.

Recently, with the war and all, I've taken more of an interest in military affairs. Lo and behold, the military publishes a lot of magazines and periodicals internally, and many of them are available free online! I like them because they don't have the macho posturing of rags like Soldier of Fortune and other right-wing civillian magazines, and read like professionals writing for other professionals on how to do their job better. Think Wired vs. Linux Journal.

List of DoD magazines
Soldiers - Official army magazine, with full PDF archive.
Airman - Official air force magazine
Marine - Official USMC magazine
Approach - Navael aviaton safety magazine
Ground Warrior - Marine training safety magazine
Infantry magazine - Army infantry magazine, article archive at findarticles.com
Parameters - The U.S. War College's periodical

Soldiers, Airman, and Marine are sort of PR-related publications, so they aren't as interesting. Approach, Ground Warrior and Infantry are written as advice and information sources for their respective professions, so they have more technical detail. I like how they give a view of day-to-day operations in the military, especially training mishaps and other mistakes you don't hear about often. Parameters is a more scholarly magazine that gives a view into what the high-level officers are thinking and planning right now, plus some military history.

They're your tax dollars at work, may as well read them. Better to be an informed citizen than an entertained consumer, especially with the war in Iraq going on.

The first computer "bug" was found by Lieutenant Grace Murray Hopper while she was on Navy active duty in 1945.

A moth found trapped between points at Relay #70, Panel F, of the Mark II Aiken Relay Calculator while it was being tested at Harvard University, 9 September 1945. The operators affixed the moth to the computer log, with the entry: "First actual case of bug being found". They put out the word that they had "debugged" the machine, thus introducing the term "debugging a computer program".

In 1988, the log, with the moth still taped by the entry, was in the Naval Surface Warfare Center Computer Museum at Dahlgren, Virginia.

Image here.

The Mark II and the bug predated the ENIAC, which was formally dedicated at the Moore School of Electrical Engineering of the University of Pennsylvania on February 15, 1946.

Moth found trapped between points at Relay # 70, Panel F, of the Mark II Aiken Relay Calculator while it was being tested at Harvard University, 9 September 1945. The operators affixed the moth to the computer log, with the entry: "First actual case of bug being found". They put out the word that they had "debugged" the machine, thus introducing the term "debugging a computer program". In 1988, the log, with the moth still taped by the entry, was in the Naval Surface Warfare Center Computer Museum at Dahlgren, Virginia.

See here.

For an idea of the power of these old-tech guns, check out this photo of the USS Iowa (New Jersey's sister ship) firing a full broadside. Note the water displacement. USS Iowa

The tooltip text has a blurb about it, although nothing too detailed:
"Arguably the true star of 'Stealth,' the makeshift-aircraft of the same name sits under the softlights of Hangar Bay Two, June 15. Despite its size, Lincoln and embarked Sailors continued business as usual while underway. (Photo by JSN David Poe)"

There is an article linked on the bottom of the page that explains it. It's for a movie by the name of 'Stealth.'

Among other tactics, the US Navy currently uses rapid fire, Gatling style guns to shoot down inbound missiles.

Only when fitted with a nuclear warhead.

Is this a good thing? We all know how it went with the invisibility power-up experiment, they tried in Philadelphia back in 1943!

name USS Abraham Lincoln

Well, Abraham Lincoln wouldn't be a name for a destroyer. President names are used for Nimitz-class super carriers. In fact, Lincoln is already taken by the CVN-72. I think destroyers take their names from famous Navy personnel.

Hmm... Well, let's ask Mr. Google. Hey, Google, how far is it to the horizon at sea level? In fact, say you're actually 100' up on the bridge of a cruiser. Google says: "11 miles".

So, yes, 250 miles is farther than the horizon. Theoretically.

And is this a new thing? Well, let's let Google tell us again...

• 5-inch deck gun? 13 miles
• 3-inch gun? 10 miles
• AGM-154? Low altitude launch - 15 nautical miles (27.78 kilometers), High altitude launch - 65 nautical miles (120.38 kilometers)

So, in other words, nothing new here in terms of "targets that have no way of retaliating". That's been the case since WWII, when in nearly all of the carrier battles, the opposing forces would be over the horizon and everything was either via plane or via large guns with planes as spotters.

-T

Hmm... Well, let's ask Mr. Google. Hey, Google, how far is it to the horizon at sea level? In fact, say you're actually 100' up on the bridge of a cruiser. Google says: "11 miles".

So, yes, 250 miles is farther than the horizon. Theoretically.

And is this a new thing? Well, let's let Google tell us again...

• 5-inch deck gun? 13 miles
• 3-inch gun? 10 miles
• AGM-154? Low altitude launch - 15 nautical miles (27.78 kilometers), High altitude launch - 65 nautical miles (120.38 kilometers)

So, in other words, nothing new here in terms of "targets that have no way of retaliating". That's been the case since WWII, when in nearly all of the carrier battles, the opposing forces would be over the horizon and everything was either via plane or via large guns with planes as spotters.

-T

Hmm... Well, let's ask Mr. Google. Hey, Google, how far is it to the horizon at sea level? In fact, say you're actually 100' up on the bridge of a cruiser. Google says: "11 miles".

So, yes, 250 miles is farther than the horizon. Theoretically.

And is this a new thing? Well, let's let Google tell us again...

• 5-inch deck gun? 13 miles
• 3-inch gun? 10 miles
• AGM-154? Low altitude launch - 15 nautical miles (27.78 kilometers), High altitude launch - 65 nautical miles (120.38 kilometers)

So, in other words, nothing new here in terms of "targets that have no way of retaliating". That's been the case since WWII, when in nearly all of the carrier battles, the opposing forces would be over the horizon and everything was either via plane or via large guns with planes as spotters.

-T

I don't know what's so 'crazy' about it. Back in the summer of 2000, I equipped our van with, among other things, a general-purpose onboard computer that can do a lot more than just GPS-based real-time mapping and route planning. It's also equipped for APRS operations, and (as soon as I get a proper multimode wireless card and an additional antenna installed up top) 802.11 networking.

At the risk of sounding a bit snobbish, I think the 12-inch TFT color display I've got up front beats the crap out of most of the "consumer" in-dash navigation units with those microscopic screens.

In anticipation of some of the questions that will likely pop into the minds of those who view the page:

(1) Yes, all the equipment is legal for me to have in there, including the lightbar.

(2) No, I'm not a 'storm chaser' (though I have been asked that a time or two). I'm a communications tech for the Washington State Patrol. I'm also disaster-response trained, thanks to the City of Kent CERT program.

(3) Yes, I have been 'first responder' in a couple of (thankfully minor) situations. I keep a full trauma kit in the van, but I pray I never need to find out how complete it is, or how well my training took.

(4) Let's just say that, besides the above, I take my hobby of amateur ('ham') radio pretty seriously, especially the parts about being ready to lend a hand in public service and voluntary support of emergency communications.

Keep the peace(es).

"As well as being the first stealth ship..."

The Norwegian KNM Skjold were built some five years ago, and do have stealth capabilities.

KNM Skjold were last year in the US to demonstrate its capabilities to the US Navy.

From http://www.knmskjold.org/english/engfacts.htm:
"For the first time radar absorbing materials are included in the loadbearing structure (structural RAM) of a vessel over large areas. This contributes to significant weight reduction compared to the conventional method of cladding this material on the outside of the load bearing structure. The ship is designed with a low number of reflective panel orientations and none right angled corners. This is the reason for the faceted external shape of the vessel."

The US Navy has had stealth (non-metal) ships in commission for a long time. Read about it here. Excellent fuel economy as well.

Not only is the predated (by a long shot) by the US Navy Sea Shadow program in the mid-80s (as pointed out by another poster), but also by the French 'La Fayette' stealth frigates (circa 1988). Modified versions of that ship are also in use by both Saudi Arabia and Taiwan.

IIRC, the United States has not lost a carrier to action or mishap since World War II.

Submarines, yes. We've lost a few of those.

I believe the distinction of being the first actually goes to good-ol USA's Navy, ARPA, and Lockheed Martin: http://www.chinfo.navy.mil/navpalib/factfile/ships /ship-sea.html

You can see lots of other examples from other countries here: http://www.lowobservable.com/shipwor.htm (as always, mod- for trumpetting the evil US as being somehow superior to Europeans on /.)

sPh

Linkified Stealth Boat Link More Pics More Pics

As well as being the first stealth ship,

No, I'm afraid that that honor goes to Sea Shadow. True, it was only a technology demonstrator, but it WAS the first stealth ship. This Swedish upstart may be the first PRODUCTION stealth ship, but it certainly ain't the first.

That said, lessons from Sea Shadow were incorporated into the Burke class Destroyers. So this isn't even the first 'stealthy' ship out here.