Forgot your password?
typodupeerror

Slashdot stories can be listened to in audio form via an RSS feed, as read by our own robotic overlord.

Cellphones

Taking the Census, With Cellphones 57

Posted by Soulskill
from the there's-an-app-for-that dept.
sciencehabit writes: If you want to figure out how many people live in a particular part of your country, you could spend years conducting home visits and mailing out questionnaires. But a new study describes a quicker way. Scientists have figured out how to map populations using cellphone records — an approach that doesn't just reveal who lives where, but also where they go every day. The researchers also compared their results to population density data gathered through remote sensing technologies, a widely-used method that relies on satellite imaging to gather detailed information on population settlement patterns and estimate population counts. They found that the two methods are comparable in accuracy when checked against actual survey-based census data, but estimates from mobile phone data can provide more timely information, down to the hours.
The Military

US Army May Relax Physical Requirements To Recruit Cyber Warriors 307

Posted by samzenpus
from the couch-patrol dept.
HughPickens.com writes Clifford Davis reports that only 30% of young people between the ages of 17 and 24 are qualified to become soldiers. This is primarily due to three issues: obesity or health problems; lack of a high school education; and criminal histories. While cognitive and moral disqualifications have held steady, weight issues account for 18% of disqualifications, and the number is rising steadily. It's projected to hit 25% by 2025. The current Army policy is that every recruit, whether enlisting for infantry or graphic design, has to meet the same physical requirements to join — but that requirement may be changing. "Today, we need cyber warriors, so we're starting to recruit for Army Cyber," says Major General Allen Batschelet. "One of the things we're considering is that your [mission] as a cyber warrior is different. Maybe you're not the Ranger who can do 100 pushups, 100 sit-ups and run the 2-mile inside of 10 minutes, but you can crack a data system of an enemy." "We're looking for America's best and brightest just like any Fortune 500 company out there," says Lt. Col. Sharlene Pigg. "We're looking for those men and women who excel in science, technology, engineering and math." Batschelet admits that a drastic change in physical requirements for recruits may be hard for some to swallow. "That's going to be an institutional, cultural change for us to be able to get our heads around that is kind of a different definition of quality," says Batschelet. "I would say it's a modernizing, or defining in a more precise way, what is considered quality for soldiers."
The Internet

Hungary To Tax Internet Traffic 324

Posted by Soulskill
from the how-to-kill-your-youtube-habit dept.
An anonymous reader writes: The Hungarian government has announced a new tax on internet traffic: 150 HUF ($0.62 USD) per gigabyte. In Hungary, a monthly internet subscription costs around 4,000-10,000 HUF ($17-$41), so it could really put a constraint on different service providers, especially for streaming media. This kind of tax could set back the country's technological development by some 20 years — to the pre-internet age. As a side note, the Hungarian government's budget is running at a serious deficit. The internet tax is officially expected to bring in about 20 billion HUF in income, though a quick look at the BIX (Budapest Internet Exchange) and a bit of math suggests a better estimate of the income would probably be an order of magnitude higher.
Businesses

An Algorithm to End the Lines for Ice at Burning Man 341

Posted by timothy
from the that-trick's-not-so-weird dept.
Any gathering of 65,000 people in the desert is going to require some major infrastructure to maintain health and sanity. At Burning Man, some of that infrastructure is devoted to a supply chain for ice. Writes Bennett Haselton, The lines for ice bags at Burning Man could be cut from an hour long at peak times, to about five minutes, by making one small... Well, read the description below of how they do things now, and see if the same suggested change occurs to you. I'm curious whether it's the kind of idea that is more obvious to students of computer science who think algorithmically, or if it's something that could occur to anyone. Read on for the rest; Bennett's idea for better triage may bring to mind a lot of other queuing situations and ways that time spent waiting in line could be more efficiently employed.
Programming

The One App You Need On Your Resume If You Want a Job At Google 205

Posted by timothy
from the surprisingly-it's-not-I-am-Rich dept.
HughPickens.com writes Jim Edwards writes at Business Insider that Google is so large and has such a massive need for talent that if you have the right skills, Google is really enthusiastic to hear from you — especially if you know how to use MatLab, a fourth-generation programming language that allows matrix manipulations, plotting of functions and data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other languages, including C, C++, Java, Fortran and Python. The key is that data is produced visually or graphically, rather than in a spreadsheet. According to Jonathan Rosenberg , Google's former senior vice president for product management, being a master of statistics is probably your best way into Google right now and if you want to work at Google, make sure you can use MatLab. Big data — how to create it, manipulate it, and put it to good use — is one of those areas in which Google is really enthusiastic about. The sexy job in the next ten years will be statisticians. When every business has free and ubiquitous data, the ability to understand it and extract value from it becomes the complimentary scarce factor. It leads to intelligence, and the intelligent business is the successful business, regardless of its size. Rosenberg says that "my quote about statistics that I didn't use but often do is, 'Data is the sword of the 21st century, those who wield it the samurai.'"
Math

Statisticians Uncover What Makes For a Stable Marriage 447

Posted by samzenpus
from the by-the-numbers dept.
HughPickens.com writes Randy Olson, a Computer Science grad student who works with data visualizations, writes about seven of the biggest factors that predict what makes for a long term stable marriage in America. Olson took the results of a study that polled thousands of recently married and divorced Americans and and asked them dozens of questions about their marriage (PDF): How long they were dating, how long they were engaged, etc. After running this data through a multivariate model, the authors were able to calculate the factors that best predicted whether a marriage would end in divorce. "What struck me about this study is that it basically laid out what makes for a stable marriage in the US," writes Olson. Here are some of the biggest factors:

How long you were dating: (Couples who dated 1-2 years before their engagement were 20% less likely to end up divorced than couples who dated less than a year before getting engaged. Couples who dated 3 years or more are 39% less likely to get divorced.); How much money you make: (The more money you and your partner make, the less likely you are to ultimately file for divorce. Couples who earn $125K per year are 51% less likely to divorce than couples making 0 — 25k); How often you go to church: (Couples who never go to church are 2x more likely to divorce than regular churchgoers.); Your attitude toward your partner: (Men are 1.5x more likely to end up divorced when they care more about their partner's looks, and women are 1.6x more likely to end up divorced when they care more about their partner's wealth.); How many people attended the wedding: ("Crazy enough, your wedding ceremony has a huge impact on the long-term stability of your marriage. Perhaps the biggest factor is how many people attend your wedding: Couples who elope are 12.5x more likely to end up divorced than couples who get married at a wedding with 200+ people."); How much you spent on the wedding: (The more you spend on your wedding, the more likely you'll end up divorced.); Whether you had a honeymoon: (Couples who had a honeymoon are 41% less likely to divorce than those who had no honeymoon)

Of course correlation is not causation. For example, expensive weddings may simply attract the kind of immature and narcissistic people who are less likely to sustain a successful marriage and such people might end up getting divorced even if they married cheaply. But "the particularly scary part here is that the average cost of a wedding in the U.S. is well over $30,000," says Olson, "which doesn't bode well for the future of American marriages."
Intel

Where Intel Processors Fail At Math (Again) 239

Posted by Soulskill
from the 1+1=3-for-sufficiently-large-values-of-1 dept.
rastos1 writes: In a recent blog, software developer Bruce Dawson pointed out some issues with the way the FSIN instruction is described in the "Intel® 64 and IA-32 Architectures Software Developer's Manual," noting that the result of FSIN can be very inaccurate in some cases, if compared to the exact mathematical value of the sine function.

Dawson says, "I was shocked when I discovered this. Both the fsin instruction and Intel's documentation are hugely inaccurate, and the inaccurate documentation has led to poor decisions being made. ... Intel has known for years that these instructions are not as accurate as promised. They are now making updates to their documentation. Updating the instruction is not a realistic option."

Intel processors have had a problem with math in the past, too.
Math

Fixing Steam's User Rating Charts 93

Posted by Soulskill
from the hmm-same-distribution-as-professional-reviews dept.
lars_doucet writes: Steam's new search page lets you sort by "user rating," but the algorithm they're using is broken. For instance, a DLC pack with a single positive review appears above a major game with a 74% score and 15,000+ ratings.

The current "user rating" ranking system seems to divide everything into big semantic buckets ("Overwhelmingly Positive", "Positive", "Mixed", etc.), stack those in order, then sort each bucket's contents by the total number of reviews per game. Given that Steam reviews skew massively positive, (about half are "very positive" or higher), this is virtually indistinguishable from a standard "most popular" chart.

Luckily, there's a known solution to this problem — use statistical sampling to account for disparate numbers of user reviews, which gives "hidden gems" with statistically significant high positive ratings, but less popularity, a fighting chance against games that are already dominating the charts.
Network

Snowflake-Shaped Networks Are Easiest To Mend 38

Posted by Soulskill
from the networks-that-make-it-feel-like-christmas dept.
Z00L00K sends this report from New Scientist: Networks shaped like delicate snowflakes are the ones that are easiest to fix when disaster strikes. Power grids, the internet and other networks often mitigate the effects of damage using redundancy: they build in multiple routes between nodes so that if one path is knocked out by falling trees, flooding or some other disaster, another route can take over. But that approach can make them expensive to set up and maintain. The alternative is to repair networks with new links as needed, which brings the price down – although it can also mean the network is down while it happens.

As a result, engineers tend to favor redundancy for critical infrastructure like power networks, says Robert Farr of the London Institute for Mathematical Sciences. So Farr and colleagues decided to investigate which network structures are the easiest to repair. They simulated a variety of networks, linking nodes in a regular square or triangular pattern and looked at the average cost of repairing different breaks, assuming that expense increases with the length of a rebuilt link. ... They found the best networks are made from partial loops around the units of the grid, with exactly one side of each loop missing (abstract). All of these partial loops link together, back to a central source. ... These networks have three levels of hierarchy – major arms sprouting from a central hub that branch and then branch again, but no further. When drawn, they look remarkably like snowflakes, which have a similar branching structure.
United Kingdom

David Cameron Says Brits Should Be Taught Imperial Measures 942

Posted by Soulskill
from the cripple-their-minds-while-they're-young dept.
00_NOP writes: Children in the U.K. have been taught in metric measures in school since (at least) 1972, but yesterday British Prime Minister David Cameron suggested that they should actually be taught in Imperial measures (which are still in use officially to measure road distances and speeds, but not really anywhere else). Is this because he hasn't a clue about science or because he is catering to a particular political base?
Education

How Tech Is Transforming Teaching In a South African Township 26

Posted by Soulskill
from the please-say-cyborgs-please-say-cyborgs dept.
An anonymous reader writes: The founders of the African School for Excellence have an ambitious goal — nothing less than redefining low cost, scalable teaching that brings international standards to the poorest schools in Africa. Their first model school is off to a good start: in just 18 months, all grade 9 students are achieving scores higher than 50% on Cambridge Curriculum Checkpoint tests, and only one student scored less than 50% in math. The national average score in math is 13%. The school relies on a locally designed piece of marking software to function. Their teach-to-pupil ratios are not great, but the teachers are committed to using technology to stretch themselves as far as they can. What's most remarkable is that the school's running costs are already half the cost of a traditional government school, and the quality of education is much, much better. All this, and they're only a year and a half into the program.
Math

Physicist Claims Black Holes Mathematically Don't Exist 356

Posted by Soulskill
from the plot-twist dept.
Koreantoast writes: Black holes, the stellar phenomena that continue to capture the imagination of scientists and science fiction authors, may not actually exist. According to a paper published by physics professor Laura Mersini-Houghton at the University of North Carolina and Mathematics Professor Harald Pfeiffer of the University of Toronto, as a collapsing star emits Hawking radiation, it also sheds mass at a rate that suggests it no longer has the density necessary to become a black hole — the singularity and event horizon never form. While the arXiv paper with the exact solution has not yet been peer reviewed, the preceding paper by Mersini-Houghton with the approximate solutions was published in Physics Letters B.

"I'm still not over the shock," said Mersini-Houghton. "We've been studying this problem for a more than 50 years and this solution gives us a lot to think about... Physicists have been trying to merge these two theories – Einstein's theory of gravity and quantum mechanics – for decades, but this scenario brings these two theories together, into harmony."
Education

How Our Botched Understanding of "Science" Ruins Everything 795

Posted by samzenpus
from the you-keep-using-that-word-I-do-not-think-it-means-what-you-think-it-means dept.
An anonymous reader writes "Pascal-Emmanuel Gobry writes at The Week, "If you ask most people what science is, they will give you an answer that looks a lot like Aristotelian 'science' — i.e., the exact opposite of what modern science actually is. Capital-S Science is the pursuit of capital-T Truth. And science is something that cannot possibly be understood by mere mortals. It delivers wonders. It has high priests. It has an ideology that must be obeyed. This leads us astray. ... Countless academic disciplines have been wrecked by professors' urges to look 'more scientific' by, like a cargo cult, adopting the externals of Baconian science (math, impenetrable jargon, peer-reviewed journals) without the substance and hoping it will produce better knowledge. ... This is how you get people asserting that 'science' commands this or that public policy decision, even though with very few exceptions, almost none of the policy options we as a polity have have been tested through experiment (or can be). People think that a study that uses statistical wizardry to show correlations between two things is 'scientific' because it uses high school math and was done by someone in a university building, except that, correctly speaking, it is not. ... This is how you get the phenomenon ... thinking science has made God irrelevant, even though, by definition, religion concerns the ultimate causes of things and, again, by definition, science cannot tell you about them. ... It also means that for all our bleating about 'science' we live in an astonishingly unscientific and anti-scientific society. We have plenty of anti-science people, but most of our 'pro-science' people are really pro-magic (and therefore anti-science). "
Encryption

Researchers Propose a Revocable Identity-Based Encryption Scheme 76

Posted by timothy
from the now-who-was-I? dept.
jd writes Identity-based public key encryption works on the idea of using something well-known (like an e-mail address) as the public key and having a private key generator do some wibbly-wobbly timey-wimey stuff to generate a secure private key out if it. A private key I can understand, secure is another matter. In fact, the paper notes that security has been a big hassle in IBE-type encryption, as has revocation of keys. The authors claim, however, that they have accomplished both. Which implies the public key can't be an arbitrary string like an e-mail, since presumably you would still want messages going to said e-mail address, otherwise why bother revoking when you could just change address?

Anyways, this is not the only cool new crypto concept in town, but it is certainly one of the most intriguing as it would be a very simple platform for building mostly-transparent encryption into typical consumer apps. If it works as advertised. I present it to Slashdot readers to engender discussion on the method, RIBE in general and whether (in light of what's known) default strong encryption for everything is something users should just get whether they like it or not.
Math

New Study Projects World Population of 11B by 2100 326

Posted by timothy
from the ok-but-only-one-of-me dept.
vinces99 (2792707) writes Using modern statistical tools, a new study led by the University of Washington and the United Nations finds that world population is likely to keep growing throughout the 21st century. The number of people on Earth is likely to reach 11 billion by 2100, the study concludes, about 2 billion higher than widely cited previous estimates. The paper published online Sept. 18 in the journal Science includes the most up-to-date numbers for future world population, and describes a new method for creating such estimates. "The consensus over the past 20 years or so was that world population, which is currently around 7 billion, would go up to 9 billion and level off or probably decline," said corresponding author Adrian Raftery, a UW professor of statistics and of sociology. ... The paper explains the most recent United Nations population data released in July. This is the first U.N. population report to use modern statistics, known as Bayesian statistics, that combines all available information to generate better predictions.

Most of the anticipated growth is in Africa, where population is projected to quadruple from around 1 billion today to 4 billion by the end of the century. The main reason is that birth rates in sub-Saharan Africa have not been going down as fast as had been expected. There is an 80 percent chance that the population in Africa at the end of the century will be between 3.5 billion and 5.1 billion people.
Education

ISIS Bans Math and Social Studies For Children 981

Posted by Soulskill
from the control-through-indoctrination dept.
mpicpp sends this news from CNN: In swaths of Syria now controlled by ISIS, children can no longer study math or social studies. Sports are out of the question. And students will be banned from learning about elections and democracy. Instead, they'll be subjected to the teachings of the radical Islamist group. And any teacher who dares to break the rules "will be punished." ISIS revealed its new educational demands in fliers posted on billboards and on street poles. The Sunni militant group has captured a slew of Syrian and Iraqi cities in recent months as it tries to establish a caliphate, or Islamic state, spanning Sunni parts of both countries. Books cannot include any reference to evolution. And teachers must say that the laws of physics and chemistry "are due to Allah's rules and laws." Update: 09/18 16:26 GMT by S : CNN has pulled the story over "concerns about the interpretation of the information provided." They promise to update it when they get the facts straight.
Math

Information Theory Places New Limits On Origin of Life 211

Posted by Soulskill
from the all-credit-to-the-genesis-device dept.
KentuckyFC writes: Most research into the origin of life focuses on the messy business of chemistry, on the nature of self-replicating molecules and on the behavior of autocatalytic reactions. Now one theorist says the properties of information also place important limits on how life must have evolved, without getting bogged down in the biochemical details. The new approach uses information theory to highlight a key property that distinguishes living from non-living systems: their ability to store information and replicate it almost indefinitely. A measure of this how much these systems differ from a state of maximum entropy or thermodynamic equilibrium. The new approach is to create a mathematical model of these informational differences and use it to make predictions about how likely it is to find self-replicating molecules in an artificial life system called Avida. And interestingly, the predictions closely match what researchers have found in practice. The bottom line is that according to information theory, environments favorable to life are unlikely to be unusual.
Stats

Statistics Losing Ground To CS, Losing Image Among Students 115

Posted by Unknown Lamer
from the big-bad-data dept.
theodp (442580) writes Unless some things change, UC Davis Prof. Norman Matloff worries that the Statistician could be added to the endangered species list. "The American Statistical Association (ASA) leadership, and many in Statistics academia," writes Matloff, "have been undergoing a period of angst the last few years, They worry that the field of Statistics is headed for a future of reduced national influence and importance, with the feeling that: [1] The field is to a large extent being usurped by other disciplines, notably Computer Science (CS). [2] Efforts to make the field attractive to students have largely been unsuccessful."

Matloff, who has a foot in both the Statistics and CS camps, but says, "The problem is not that CS people are doing Statistics, but rather that they are doing it poorly. Generally the quality of CS work in Stat is weak. It is not a problem of quality of the researchers themselves; indeed, many of them are very highly talented. Instead, there are a number of systemic reasons for this, structural problems with the CS research 'business model'." So, can Statistics be made more attractive to students? "Here is something that actually can be fixed reasonably simply," suggests no-fan-of-TI-83-pocket-calculators-as-a-computational-vehicle Matloff. "If I had my druthers, I would simply ban AP Stat, and actually, I am one of those people who would do away with the entire AP program. Obviously, there are too many deeply entrenched interests for this to happen, but one thing that can be done for AP Stat is to switch its computational vehicle to R."
Education

It's Dumb To Tell Kids They're Smart 243

Posted by timothy
from the converse-is-also-true dept.
theodp writes Over at Khan Academy, Salman Khan explains Why I'm Cautious About Telling My Son He's Smart. "Recently," writes Khan, "I put into practice research I had been reading about for the past few years: I decided to praise my son not when he succeeded at things he was already good at, but when he persevered with things that he found difficult. I stressed to him that by struggling, your brain grows. Between the deep body of research on the field of learning mindsets and this personal experience with my son, I am more convinced than ever that mindsets toward learning could matter more than anything else we teach." According to Dr. Carol Dweck, who Khan cites, the secret to raising smart kids is not telling kids that they are. A focus on effort — not on intelligence or ability — says Dweck, is key to success in school and in life.

Put your Nose to the Grindstone! -- Amalgamated Plastic Surgeons and Toolmakers, Ltd.

Working...