Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Comments

top

The Most Highly Cited Scientific Papers of All Time

pehrs Re:results from different practices among discipli (74 comments)

In engineering, there tends to be less of a tendency to cite a paper with methodological info: Very few people using an FFT cite the Cooley-Tukey paper; likewise, someone talking about using an ADC for sampled data isn't going to cite Nyquist, even if they say "the sampling rate was 5 time the Nyquist frequency". Likewise, in engineering, you don't see: The dice were attached to the substrate using a eutectic mixture of lead and tin as recommended by Agricola in "de re Metallica".

Yes and no. In computer science experienced authors rely on a common and rather broad knowledge base when writing their publications. There is a tradition not to cite things which are part of the common knowledge. I would not cite just because I was using the FFT, unless I was doing something out of the ordinary with it which actually requires understanding all the details of the original publication.

A very common sign of an inexperienced author is sloppy references. Typically there are too many references, and to works which are not strictly relevant for the author. When you see an introduction with 60 references outside a survey you can usually toss the paper in the trash bin and tell the authors to start over...

yesterday
top

David Cameron Says Brits Should Be Taught Imperial Measures

pehrs Re:Idiot (942 comments)

The only problem with that is that there are at least 3 definitions of cup that I know of (metric, imperial and U.S. customary), which kind of defeats the purpose of having a recipe in the first place.

And the approximation problem is something you constructed for yourself. Here we typically describe recipes using deciliters. Which is a nice, standard unit which you can scale up or down as needed. And, no, we don't start with imperial measurements and round off. If you want to do scones my way you will have to add 1.26 cups of standard milk, 3.38 cups of flour and 0.22 lb butter (among other things).

about a month ago
top

Ebola Quarantine Center In Liberia Looted

pehrs Re:Please stop and think (359 comments)

A good and insightful post.

The only thing you forgot is to mention why Liberia is one of the most miserable parts of Africa.

Liberia is the only country in Africa founded by United States colonization while occupied by native Africans. It was financed by the American Colonization Society, an organization created to remove unwanted freed black slaves from America, to avoid a slave uprising like what happened in Tahiti. The colonizers became known as Americo-Liberians and promptly started to enslave the locals and selling them back to the US (with support from the American Colonization Society). The Americo-Liberians, led the political, social, cultural and economic sectors of the country and ruled the nation for over 130 years as a dominant minority. The atrocities under that regime were too many to count.

The US continued to keep it a hell hole in the effort to fight communism, and from 1940 and forward pumped enormous sums into the budget country (about half the GNP was American aid for a while...). Of course most of this money vanished in corruption. But in return the evil communists were kept out. Eventually there was a coup in 1980, finally removing the Americo-Liberians, and starting two civil wars, killing about half a million and displacing about half of the country population. About 85% of the people live under the poverty level today.

We sometimes speak of the Ghost of King Leopold, after the horrors in Congo. But when it comes to colonialism the American version seen in Liberia was at least as bad. And by doing it as a private enterprise they ensured that, unlike the state colonies, there never was a decolonization with support for forming a stable state.

about 2 months ago
top

Point-and-Shoot: TrackingPoint's New Linux-Controlled AR-15s

pehrs Re: Apply liberal amounts of gloss. (219 comments)

You would be surprised how bad people shoot in the real world... I hunt. I fire about 50 shots on big game (mostly boar, deer and moose) a year, and well over thousand if you count small game. I compete, primarily in sporting and skeet but also 300 meter rifle.

In my experience the wast majority of shooters have a hard time hitting a deer sized targets with a rifle at 300 meters without special training. Add any sort of complication, like a little bit of stress, moving target, bad light or the like, and most people won't hit a deer sized target consistently (that is, 10 out of 10 in the heart-lung area) at 100 meters. The performance of the cartridge barely matters. Most people simply need a lot of training to aim and fire a rifle well, especially under stress.

I spend a considerable amount of my spare time tracking down deer which were wounded by people with the "Any dope can make a 300 yard shot" attitude. They are typically not quite so tough at 4 am in the morning when we have spent a few hours tracking down the deer they wounded. While it is good training for the dogs, and it is very rewarding work, it would be better if people learned how hard it is to shoot well on distances over 100 meters.

about 3 months ago
top

A Skeptical View of Israel's Iron Dome Rocket Defense System

pehrs Re:Subject bait (379 comments)

Railroad ties make decent improvised shelter roofs.

Decent but not good. They are likely to create really nasty shrapnel if hit. They are heavy. And they are typically covered with creosote, which is something you do not want in your home if you can avoid it. In general, wood may be cheap, but it's not a very good material for building shelters against explosives..

If you spend the time and energy building a bombshelter you use the right materials, which are typically steel and reinforced concrete.

about 4 months ago
top

The World's Worst Planes: Aircraft Designs That Failed

pehrs Re:Does not matter (209 comments)

I see your Goblin, and raise you a De Lackner HZ-1 Aerocycle.

The operator is standing on an open hub platform on top of a helicopter rotor. What could possibly go wrong?

In the military we have a word for that kind of contraption. It's "Skeet".

about 5 months ago
top

Xbox One Reputation System Penalizes Gamers Who Behave Badly

pehrs Re:Bullying (183 comments)

Having been involved of the design of a similar system a few years back, I found this remarkably easy to handle.

What you do is that you cluster people based on their opinions, and add a fading of old opinions. People who share good opinion about each other are in the same cluster. People who dislike each other are in different clusters. So, what happens in the end is that the "nice" people end up in a few big "nice people" clusters, and you get lots of small clusters of jerks. In the system we designed we actually provided individualised feedback to the users, as in "From the perspective of your cluster, this person has good/neutral/bad standing". In practice it didn't take long before people with good behaviour were efficiently separated from the rest.

Giving bad score to lots of people needlessly quickly gets you kicked out of the "good people" cluster. Congratulations, you now get to play with the rest of bullies.

Of course, this is just basic computer science and statistics...

about 7 months ago
top

Child Porn Arrest For Cameron Aide Who Helped Plan UK Net Filters

pehrs Re:victimless crime (205 comments)

<quote><p>How is the possession or viewing of child porn a crime at all? I dare someone to prove the harm in possessing/viewing cold porn</p></quote>

There are a lot of problems with many child pornography laws, but there are also very good cases to be made for banning possession and viewing of it.

1. If there is a market for child pornography there is a stronger incentive to abuse children. People will produce more of it where it is actually legal to produce (or the legal system is too weak to stop it).

2. There is a strong stigma connected to being presented in pornography. This stigma and the associated injury does not decrease with time. Those who have experienced it describe it as a form of constant, ongoing, abuse that they have to live with their whole life. While you may not mind people jacking off to pictures of children, it is not something the children in the picture can consent to.

about 8 months ago
top

EU Proposes To Fit Cars With Speed Limiters

pehrs Re:No need for cameras. (732 comments)

I believe all major producers of cars have active safety systems, using proximity sensors to reduce the risk of accidents. For example Volvo has the City Safety system, which automatically breaks the car in case you get close enough to a car in front that there is a collision hazard. While it won't prevent all accidents it reduces the risk of an accident.

So, it's a nice idea, it works, is implemented and you can buy it with your new car for a reasonable sum ;)

about a year ago
top

Ask Slashdot: How Do You Prove an IT Manager Is Incompetent?

pehrs Management consulting... (331 comments)

Management consultant does this all the time. It really is a task for somebody focusing on management and organization, not on technology consultant. So call some nice people at a company like Arthur D. Little, McKinsey or similar. Of course, they will charge a lot to sort out this kind of situation.

If you really want to get into management consulting the easy path is typically to toss out all the value words and feelings you may have about the people involved. Don't even think words like "loathed", "ineffective", "parroting" etc. Instead you go to the hard facts. What is the properties of the department? How does it compare to other similar departments? Do they have procedures and routines? What are they? Do they have qualifications in relevant fields? etc. Don't fall in the trap of trying to pin everything on a single person, as this kind of situation is typically part of the culture of the department. The head of the department is a symptom, not the single cause of it all.

Also remember, that those that hired you are probably also responsible for hiring that head of department. Calling him incompetent is roughly the same thing as calling the people who hired him incompetent. Not a good way to build professional relationships or helping people.

about a year ago
top

Astronauts Fix Phantom Space Station Ammonia Leak

pehrs Re:Wetware Controller advantages (54 comments)

If you remove the humans you can also remove the large, heavy and complex life support systems they need. The life support systems are a major consumer of power on the ISS, and a reason they have so many solar panels that can fail, as well as a constant source of small and large breakdowns in itself.

In the end it is a matter of what you want to do with the spacecraft. Unmanned spacecraft are cheap and reliable. Manned craft are a little more flexible, but expensive and unreliable. Even with the ability to repair stuff humans have they are hampered by the lack of tools and spare parts in space, so it's very unlikely that manned spacecraft will ever be as reliable as the simple robotic probes.

about a year and a half ago
top

A Sea Story: the Wreck of the Replica HMS Bounty

pehrs Re:Epitath (184 comments)

I have worked on navy and civilian ships, and I can't imagine going to sea with sawdust or wood chips in the engine room. Doing it in heavy weather is unthinkable and the thought sends a shiver up my spine.

Maintaining a ship takes time and dedication. In the time of the tall ships they had the boatswain and the carpenters. Today we have the chief and the engineering staff. An experienced seaman in either position would probably have stopped this trip, and that is one very important reason that the chief should be on equal standing with the captain.

about a year ago
top

NY Times' Broder Responds To Tesla's Elon Musk

pehrs Re:The reporter does not like electric vehicles (609 comments)

I am not sure what fuzzy fantasy world you life in, where data is TEH INCORRUPTABLE NUBERZZZ!!!!, but the data I regularly handle can be tampered with, use strange units, measure the wrong thing, use a weird scale and so on regardless of being presented as numbers or as charts. A bit of rounding and 0.49 becomes 0, for example.

A chart is just a presentation of data. A remarkably useful one, as humans have a much easier time analyzing trends and patterns in a picture compared to a presentation based on a list of numbers.

Oh, by the way, to make your own inference you typically need contextual information (metadata). If the data is presented as numbers or as charts is of much less importance.

about a year and a half ago
top

Supreme Court Hearing Case On Drug-Sniffing Dog "Fishing Expeditions"

pehrs Re:As good as lie detectors? (451 comments)

Congratulations, this must be one of the more ignorant comments I have seen on Slashdot in a long while.

Dogs have an almost insanely good sense of smell. For a dog to smell a bag of narcotics is about as hard as for you to smell if somebody opened a bottle of ammonia under your nose. The big problem is getting the smell out of your nose.

Training a drug sniffing (or any type of ID dog) involves teaching the dog first to identify a number of substances and then "mark" them. Marking is typically done either by the dog freezing and pointing with the nose, or sitting down. For a dog to be qualified you have a number of tests. Tests here involves the dog having to search 12 people, some of whom who may carry narcotics. Those not carrying narcotics get identical objects to hide on their persons. The handler, and the person holding the object, does not know if it is the real deal or not until after the test. If the dog misses a person, or marks the wrong person, it, and the handler, fails to qualify. And, yes, it's not unusual with a lineup where nobody carries anything.

A similar test often used is when a luggage band at an airport, where the dog must mark the specific bags containing explosives or narcotics. So the dogs and handlers certainly have to prove that they are able both to identify the substance and and that they know when it's not there.

Dogs are not infallible.They get tired, bored and exhausted just like their handlers. But it's not just a matter of a 'trained' officer having an 'opinion' about if the dog found something.

about 2 years ago
top

17th Century Microscope Book Is Now Freely Readable

pehrs Re:Hooke the pretender (116 comments)

Isaac Newton was a very good scientist, and an even better politician. Actually, "ruthless" would probably be the best term to describe the man. He spent years discrediting anybody who had crossed him, frequently postmortem. You see, Isaac lived for a long time, and took the liberty to spend the last few years of his life smearing people like Hooke and Halley.

There is a reason he was chosen to head the royal mint, where he ensured that some 30 coiners ended up hung, drawn and quartered in less than a year.

about 2 years ago
top

US Presidential Debate #2 Tonight: Discuss Here

pehrs Re:Giving more people more money (706 comments)

Gaaa. So many wrong. So many wrong.

1. Small business are usually not very efficient. It's the medium-large size companies that get the benefits of scale. An economy dominated by small business can not develop. See, for example, the department store mess in India.

2. No, increased personal risk does not promote the creation of small companies, Actually, I would argue the exact opposite. When somebody says that it is too risky to start a business it means that your social safety system is not strong enough. In a country with strong social security an entrepreneur can take risks and try starting a business without risking things like health-insurance. See, for example, the high rate of successful small companies in countries with exceptionally high taxes and strong social security like the Nordic countries.

3. No, a bank will NEVER lend money to a person wishing to start a new company unless he has a good collateral. And if he has a good collateral they don't really care what he does with the money. Large loans "on your good name" is a thing that vanished about 100 years ago. An investor might invest money in a fledgling company, but they will at the very least demand equity. See, for example, any textbook in basic economy.

4. Considering your last point, why don't you argue for lower taxes on employment, and higher taxes on corporate gains? You know that the vast majority of the earning from small business are paid out as salary and not as dividend, right?

about 2 years ago
top

Microsoft Wants To Nix Data Center Backup Generators

pehrs Re:If it ain't broke (141 comments)

Having worked at a small high-availability data center I can assure you that AT&T does it right. Just starting the generators is not enough. You must also test your UPS systems, line sensing equipment and the long and complex line of electrical equipment that must work if you are to get a clean handover from the power grid over UPS to generator. Finding a failure in the chain is not nearly as painful when you can fall back to grid power while troubleshooting.

One of the more sneaky things to do to a facility is to walk into the transformer and kill off one or two phases, but leave the rest live. If their line sensing equipment does not work correctly (or the relay to cut out the power grid fails under load) the effect can be spectacular, and expensive. This is a classic problem not caught by just starting up the generators once a week.

more than 2 years ago
top

SQL Vs. NoSQL: Which Is Better?

pehrs In other forums... (306 comments)

<rant mode>
I had a look in the other forums I frequent, to look around for similar questions. And look what I found:

In the construction forum:
Screwdriver vs Hammer: Which is better?

In the art forum:
Pencil vs Pen: Which is better?

In the transportation forum:
Walk vs Drive: Which is better?

In the pets forum:
Cat vs Dog: Which is better?

In the energy forum:
Wind vs Hydro: Which is better?

And guess what? They all came to the same conclusion. "It depends".

Can we now stop posting "SQL vs NoSQL: Which is better?" stories like this one, as they are utterly pointless?

For the article to be useful the author needs to chose and describe use cases that actually matters to the reader. "Better" is not a use case, and I really hope people don't pick the backend for their application based on how easy it is to implement a few tiny examples in C# or Node.js which is the only thing resembling a use case in that mess of an article.
</rant mode>

more than 2 years ago
top

Fires Sparked By Utah Target Shooters Prompt Evacuations

pehrs Re:Bunk. (709 comments)

...only in America...

Let me tell you how it works in the old world...

Modern assault/battle rifles makes a bad choice for a hunting rifle in my experience. To list a few reasons:
* Innate accuracy is horrible
* Many are chambered for calibers unsuitable for big game (why hunt deer with .223 Remington when there are so much better choices?)
* Stocking, balance and design are not suitable for typical hunting scenarios.
* Sensitive to dust and dirt.
* You very rarely need more than one shot to down your game. (And when you do, you have time to chamber a new round before you realize that it's needed)

Anybody showing up with a military style rifle to a hunt where I hunt would meet a contempt that is hard to imagine. Semi-automatic rifles designed for hunting are grudgingly accepted. We do not wage war on our game, and we do not need military equipment.

more than 2 years ago
top

Ask Slashdot: Advice For Budding Scientist?

pehrs Some comments (279 comments)

Now, I am in a different field, but I think I can give some hints.

First of all, people often want to see things as fraud/not fraud. But that is rarely true. Scientific work has different degree of rigidity depending on who does it and what the goal is. You can see the scale as something like "Fraud", "Criminal negligence", "Bad study", "Meh", "Good study", "Impressive study" and "This should be in nature/science/what-ever-the-top-publication-of-your-field-is". You have to consider the whole scientific process to see where a paper falls. Even if you do flawless statistics and report everything in detail your study can be crap if you choose the wrong methods. What would be fraud from a skilled researcher might just be an oversight from a less skilled one.

Secondly, this is such a tiny, unimportant, part of why you are getting into science/getting a PhD. If I was to give you any advice when you are getting into science it would be the following:
1. Make sure you love the field. If you are not ready to spend a whole weekend in the lab sweating while everybody else is out having fun it's not a very good path to take. Overtime is pretty much the norm where I work.
2. Make sure you love your adviser. He/she can make or break your career. And you are going to spend more time with him/her than your girl/boy friend, should you have one, over the next 7 years.
3. Make sure you have a backup plan. A majority of those with a PhD does NOT work in academia. You need to know stuff that lets you survive outside a university. Management, economics, applied science... Pretty much anything will do, as long as you can go out the doors and feel confident that somebody out there will hire you.
4. Remember that you are investing many productive years into this. Statistics says that your lifetime earnings will go down. Be ready to see your friends that went out in industry earn twice as much as you do.

more than 2 years ago

Submissions

top

Deepwater Horizon rig Accident Report is online

pehrs pehrs writes  |  more than 4 years ago

pehrs (690959) writes "The full accident report from the blowout at Deepwater Horizon is online, including an executive summary in video format and a huge amount of technical details. The report does not assign blame, but does list 8 major barriers that were breached, causing the accident."
Link to Original Source
top

pehrs pehrs writes  |  more than 7 years ago

Avalanche writes "Allegiance, released 2000, was a grand experiment created by Microsoft research in a try to get into the pay-per-month online market. After a long and rough road the project was abandoned 2002 and ended up open source in 2004. A group of developers has been working on the project ever since and a few days back the development team released the latest version, R3, including a new network code allowing play from behind NAT. The game and source code are freely available to those interested in playing or tinkering. Sadly the game uses DirectX and .net (for cheat prevention in online games), so it's not developed under Linux. (FYI: I am a developer of FAZ)"

Journals

pehrs has no journal entries.

Slashdot Login

Need an Account?

Forgot your password?