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text:
Let $P_i(x)$ be polynomials $i=1,...,n$, $s$ some value, and $g$ a generator of a group $G$ where the discrete logarithm is hard.
Assume a prover wants to convince a verifier having access to the values $g^{P_i(s)}$ that it knows polynomials $q_i(x)$ such that the following equation holds:
$q_1(s)*P_1(s)+q_2(s)*P_2(s)+\ldots+q_n(s)*P_n(s) = 1.$
The prover thus sends the verifier the values $g^{q_i(s)}$ and uses bilinear maps to verify the correctness of the answer.
Can the following equation tell me whether it has correctly computed the $q_i(s)$: $$e(g^{q_i(s)},g^{P_i(s)}) = e (g,g)$$ where $e$ is a bilinear map $G\times G\rightarrow G_1$.
So basically I want my bilinear map to verify on the exponents while hiding them. Is the second part of the equation correct? Or should it be 1, or $e(g,g)^{ord(G)}=1$?

subset: commoncrawl


text:
A program that prepares individuals to apply technical knowledge and skills to install, operate, maintain, and repair electric apparatus and systems such as residential, commercial, and industrial electric-power wiring; and DC and AC motors, controls, and electrical distribution panels. Includes instruction in the principles of electronics and electrical systems, wiring, power transmission, safety, industrial and household appliances, job estimation, electrical testing and inspection, and applicable codes and standards.
A program that prepares individuals to apply technical knowledge and skills to install and repair household, business, and industrial security alarms, sensors, video and sound recording devices, identification systems, protective barriers, and related technologies.
Inspect, test, repair, or maintain electrical equipment in generating stations, substations, and in-service relays.
Install, maintain, and repair electrical wiring, equipment, and fixtures. Ensure that work is in accordance with relevant codes. May install or service street lights, intercom systems, or electrical control systems. Excludes "Security and Fire Alarm Syste
Install, program, maintain, and repair security and fire alarm wiring and equipment. Ensure that work is in accordance with relevant codes. Excludes "Electricians" (47-2111) who do a broad range of electrical wiring.
Install, inspect, test, maintain, or repair electric gate crossings, signals, signal equipment, track switches, section lines, or intercommunications systems within a railroad system.


text:
Abby is a darling gal who runs a blog titled Just a Girl and Her Blog. She shares her daily sweetness and home projects with the world wide web, and recently revealed her beautiful master bedroom makeover. Although there is endless goodness in her room update, you know my heart did back flips for one part in particular. The concealed gift wrap organization. It's fan-freaking-tastic!!!
What is the main function of the project?
"This trunk that we use for gift wrapping supplies resides in our newly-refreshed bedroom! Because we live in a small-ish townhouse, many of our pieces of furniture do double or triple duty. The trunk provides a seating area for putting on shoes, a resting place for the laundry basket while I'm putting away clothes, and now has the additional responsibility of corralling all of our wrapping paper, gift bags, gift boxes, and bows so that we always know where to find exactly what we need."
Any superstar tips for keeping it organized?
"Everything has a specific place {with a label!}. It can be really tempting to throw everything in the trunk and just close the lid, but when everything has its own little area, it's easy to return things to their rightful 'home' and keep it organized. I really tried to use the sides of the trunk and maximize the usage of vertical space so that everything wasn't laying on top of each other, which helps too."
What items were essential when working on this project?
"The tension rod made it super easy to corral the gift bags and boxes and Command strips and hooks really helped with the hanging storage. I am definitely a fan of baskets and bins and incorporating them into this space to hold ribbons and bows was a no-brainer! And, as always, labels, labels, labels!
In addition to printing and laminating labels for each section of storage, I used washi tape and my label maker to label my greeting card organizer. The little pops of color make me smile every time I open it!"
What did you do to go the extra mile and "Make it Pretty"?
"Even though I knew it would be underneath the wrapping paper and other supplies, I lined the bottom with pretty chevron shelf liner that I picked up at T.J. Maxx. Every once in a while I'll catch a glimpse of it peeking through, and it makes me smile! Plus it helps to protect the trunk a little bit.
The other colorful accessories also helped to prettify this little beauty--labels and various baskets and bins complimented the already colorful wrapping paper, gift bags and boxes, and ribbons and bows."
What items did you DIY to stay on a budget?
"I was making over the rest of the room, so this trunk needed some major love while I was at it! It started out pretty rough.
The paint made a huge difference. This was my first project using Annie Sloan Chalk Paint, which was really fun. I loved that it helped me to take an old, worn out hand-me-down piece and give it new life again. It gives the room more of a personal touch instead of going out and buying something off the shelf.
Once the trunk was painted, the organizational systems just fell into place. I used an inexpensive tension rod, wire bin, and expandable file from Target and the little green bins are from Dollar Tree--4 for $1! Holla!"
How has this project impacted your life for the better?
"I have always loved making gifts look extra special with pretty paper and bows, but I was so not motivated when I had to look through a big pile of crunched up, unorganized materials to try to find what I needed.
Our new system makes it so easy to find what I need quickly and then just pop it back into its place. Everyone is going to be getting the cutest wrapped gifts from us!"
And since we all love a good before and after:
How can you not want to organize your gift wrap after a story like that? So much about this project to crush on!
- The trunk makeover alone is beautiful! I love how the paint transformed her outdated storage.
- Lining anything with bright and pretty paper is sure to bring a smile to your face.
- The card organizer was functional from the start, but the addition of pretty washi labels really makes it sing! And I love that she selected an accordion organizer for her cards. Smart girly!
- The tension rod really adds oodles of storage along the edge of the trunk, I love that gift bags and boxes can be easily stored in a compact way.
- Abby added hooks for her scissors and supplies, right on the walls of the trunk. Another great use of space and they will always be easy peasy to find.
- The use of a small dowel for her ribbon within the basket is another great tip! It is simple to swap out ribbon, and to quickly pull some in the middle of a wrapping job.
- She put baskets inside of baskets! They act as great dividers for her bows and gift toppers.
- This project was all done on a budget and with inexpensive solutions from Target and the dollar store. Yet it looks like a million buckaroos!
A HUGE thank you to Abby for submitting her darling project and giving me a little extra inspiration to get my wrapping supplies under control. Seriously, mine look far worse than her before image... it isn't a pretty picture.
Were you able to snag some ideas and inspiration from this wonderful feature as well? Where do you store your wrapping essentials?
ATTENTION!! Want to be featured in a Reader Space edition? Have an awesome organizing story to share? I am looking for projects that have made a positive impact to your life. Please submit your story and photos here and I would heart to feature them right here, on the blog!! Photos should be high resolution and unedited. Please include a description of the project, including any costs, inspiration, and how it has changed your life and routine for the better! Oh, and no worries my friends, we will NEVER judge "before" pictures because that just wouldn't be nice! Only love goes on at this blog!


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35 Tips to Furnish Your New Home for Less
Buying a new home is one of the most exciting experiences in life. And if you're like most homebuyers, you'll be planning your furniture placement and decor before the ink dries on your offer letter.
But before you run to the nearest home goods store, take a deep breath. First, you'll need to delay any major purchases before you close on your new home. A large outlay or additional line of credit could lower your credit score and, thus, impact your mortgage terms.1 Second, moving and closing costs can add up quickly, so it's important to be strategic with your remaining budget.
But don't worry! There are plenty of ways to save on home essentials, and we've rounded up some of our favorites to share with you.
According to Home Advisor, the national average cost to furnish a new house is $16,000, but it can easily soar higher.2 That's why we recommend starting with a thorough assessment of what you already have and what you actually need to start life in your new place. Here are some steps to help you prioritize your purchases and keep spending in check.
- Make a list of everything you need. Going room by room could help you brainstorm—for example, you might list items ranging from a mattress to blackout curtains for your new primary bedroom.
- Inventory what you already have. Cross the big (dining table) to the small (kitchen knives) off your list as you go.
- Divide the remaining items into three groups: things you need right away (a mattress), items you'd like to have in the near future (a coffee table for your living room), and pieces that can wait (an area rug).
- Calculate your budget. Figure out how much money you'll have available for immediate purchases after the sale has closed, and start researching the items on your priority list to understand how they'll fit into your budget.
- Don't rush the process. Bringing older items to your new space doesn't mean you need to keep them forever. Consider hanging onto pieces that can tide you over for a year or two until your bank account has recovered from the costs of a home purchase.
Before you start shopping, make sure you know which appliances and fixtures are included with your home purchase. We can inform you of the standard contract terms when you're making an initial offer and note any additional items that you would like to request.
Did you know that some home items predictably go on sale at certain times of the year? If you can wait to buy these pieces when prices are lower, you could save significantly. Here are some of the best times to buy household essentials:3,4
- Bedding and linens: January
- TVs: Black Friday/Cyber Monday and late January (before the Super Bowl)
- Furniture: February and August, as well as Black Friday, Memorial Day, and Labor Day
- Large appliances: Labor Day through October
- Small kitchen appliances: May
- Mattresses: Holiday weekends, especially Memorial Day, Labor Day, and 4th of July
- Vacuum cleaners: April
- Tools: June
- Outdoor furniture: August through October
Generally speaking, holiday weekends (as well as Black Friday and Cyber Monday) tend to be great times to find deals. If the item you're looking for is seasonal—like patio furniture or holiday decorations—waiting until the end of that season usually pays off.
Can't wait for a sale? It's time to think outside of the box (the big-box stores, that is). There are plenty of surprising places to find great furniture and houseware deals.
- Check out overstock and liquidation stores. These stores purchase items other retailers haven't sold and offer them at a steep discount. The inventory can be hit or miss, but you can often get a great deal if you find what you're looking for.5
- Try private membership/warehouse stores. Retailers like Costco and Sam's Club often have great deals on home goods. If you're not already a member, ask family or friends if they are willing to take you to look around before you commit.
- Consider open-box items. When buyers return items like furniture or electronics, retailers can't always sell them as new, even if they haven't truly been used. Look online for open-box deals from retailers like Wayfair and Amazon Warehouse or visit local retailers to see what they have in stock.
- Give scratch-and-dent appliances a chance. These appliances are brand new but sold at deep discounts because their external packaging was damaged. Typically, this means that flaws are purely cosmetic—but it's always possible that the merchandise has suffered more serious damage. So, be sure to check out the appliances carefully and ask about included warranties.6
- Expand your window treatment search. Window treatments can be surprisingly expensive, but it's often possible to save by buying off-the-shelf offerings in standard sizes. If you need a custom size or material, consider ordering online from a discount supplier and installing them yourself.
- Shop secondhand. In addition to thrift stores and garage sales, Facebook Marketplace, NextDoor, and Craigslist are all great places to find deals in your area.
Are alternative shopping sources still a stretch for your budget? Check out local Freecycle or "Buy Nothing" groups, which are often hosted on Facebook. Participants offer big and small items they no longer need—everything from furniture to clothing hangers—for free to other members.7,8
Many people don't realize that prices for home goods, from furniture to appliances, are often negotiable. While asking for a discount can be intimidating, it's common practice in many industries, although more so at independently-owned stores than chains. Here are a few tips:9,10
- Comparison shop before you walk into a store. If you can find a lower price for the same item elsewhere, many retailers will match it.
- Ask the store associate or manager for the best price available. They may be able to offer additional discounts or coupons.
- If you can pay in cash, ask if you can get a discount for doing so. The seller may be happy to offer a small price reduction to avoid paying processor fees.
- Call ahead to ask about applicable discounts. Some retailers offer price reductions for active military, veterans, teachers, first responders, or senior citizens on certain days or times of the year.
- Point out scratches or dings to the sales associate. They may be willing to offer a discount to compensate for the imperfection.
- Ask about floor models. Many stores offer these pieces at a lower price, even if they're in like-new condition.
After you've negotiated a killer deal, don't forget to ask for free or discounted delivery! Sometimes furniture and appliance stores will offer complimentary delivery or installation if you spend a certain amount or purchase multiple items.
Every penny counts when you're on a budget—and spending a little extra time maximizing reward programs and discounts is usually worthwhile.
- Sign up for a change of address kit with the United States Postal Service. You'll need to do anyway to forward mail to your new address, and it comes packed with valuable coupons.11
- Make sure you never miss a sale. Sign up for your favorite retailers' email lists and follow them on social media for discounts and sale alerts.
- Take advantage of loyalty programs. If you're making a big purchase or getting multiple items from one store, ask about free loyalty programs. Signing up often comes with an introductory coupon.
- Consider store credit cards (carefully). Store credit cards can offer significant discounts—but only charge items you can pay off right away to avoid interest, and never open new lines of credit until your home purchase is complete, since it can affect your credit score.
- Enroll in coupon and cashback programs. When you're shopping online, programs like Rakuten and Honey can help you find coupon codes and give you cash back on purchases.
While you're at it, why not set up a housewarming registry?12 You can share the link with family and friends if they ask what you need—and you can also use it to score discounts. Many stores offer a percentage off to help you buy unpurchased items on your registry.
If you want to avoid a cookie-cutter home aesthetic—and save a few bucks—try reimagining your existing furniture and how it could fit into your new space. Here are a few of our favorite strategies.
- Repurpose what you have. Instead of buying a new item to fit a specific purpose, ask yourself if you can use what you have in a different way. For example, repurpose an old dresser as a television stand or use a mismatched dining chair in your home office.
- Upgrade existing items. Sometimes, a new coat of paint or varnish, or simply swapping out drawer pulls and handles, can lend a new lease on life to an old piece of furniture. You can also keep this strategy in mind if you see second-hand items that would be just right if they were a different color or had nicer fixtures.
- Reupholster instead of buying new. If you have a tired-looking sofa or chair that's still comfortable and stable, think about getting it reupholstered in new fabric instead of replacing it.
- Get handy. Building furniture is certainly not for everyone, but with some basic tools and help from the internet, you may find that simple items like headboards are well within your grasp. You might also be able to repair pieces you already have and avoid shopping altogether.
Do-it-yourself projects can be fun, but they aren't for everyone. If you'd like some professional help, reach out for a list of our recommended service providers.
We know budgeting for a new home can be overwhelming, and we want to make the process easier for you. If you're considering a home purchase, we can advise you on a realistic budget and help you review your options. We can also offer insights on other financial considerations and programs and incentives that can help make homeownership more attainable. Reach out for a free consultation.
The above references an opinion and is for informational purposes only. It is not intended to be financial, legal, or tax advice. Consult the appropriate professionals for advice regarding your individual needs.
- Bankrate –
https://www.bankrate.com/mortgages/avoid-mortgage-closing-missteps/ - Furniture Bank –
https://www.furniturebank.org/how-much-does-it-cost-to-furnish-an-apartment/ - US News –
https://money.usnews.com/money/personal-finance/saving-and-budgeting/articles/the-best-time-of-year-to-buy-everything - NerdWallet –
https://www.nerdwallet.com/article/finance/wht-to-buy-every-month - Business Insider –
https://www.businessinsider.com/personal-finance/strategies-to-save-money-on-furniture-for-my-new-home?r=US&IR=T - CNET –
https://www.cnet.com/home/kitchen-and-household/buy-scratch-and-dent-appliances/ - Real Simple –
https://www.realsimple.com/home-organizing/green-living/buy-nothing-groups - Freecycle –
https://www.freecycle.org/ - Consumer Reports –
https://www.consumerreports.org/cro/magazine/2013/08/how-to-bargain/index.htm - Realtor.com –
https://www.realtor.com/advice/home-improvement/furniture-stores-money-saving-tricks/ - The Krazy Coupon Lady –
https://thekrazycouponlady.com/tips/money/usps-moving-coupons - Taste of Home –


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Republicans: Rework Obamacare to win elections
By Peter Morici Republicans should stop cheering for Obamacare to fail. It may be dreadful, but going back to what we had before is not possible. The real political hay is to be made improving the law to lower prices and premiums—details Democrats forgot. Even a community activist from Chicago knows that to sell tofu at less than it really costs—and to give a lot away for free—some folks have to be taxed and many have to pay too much. Since covering millions without insurance is a big kahuna, the pain for some must be big but skillfully crafted. Obamacare imposes more than a dozen new taxes, highly focused on those who will profit from more customers—for example, the levy on medical device makers and insurance companies—or generally don't vote for Democrats anyway—the 3.8 percent tax on interest income for richer Americans. Only five percent of the population is covered by individual health insurance policies, vulnerable to cancelation letters, and hence likely to face higher premiums. Nearly half are small entrepreneurs, and though highly vocal, most get their reinforcement watching Fox, not MSNBC. Even if Obamacare could be repealed after the next election, those victims could not get back their old policies. Insurance companies have replaced those with much more profitable schemes. Markets for health services and insurance are inherently local. Obamacare reorganizes markets for individual insurance policies down to the county level in such a way that only one or a few companies serve many markets. Often, those insurers have not pressed providers to offer the same low prices as available in more competitive locations. As the service providers become comfortable, padding costs and charging more, they will strongly resist new insurance companies entering their markets, seeking lower prices to charge lower premiums. In many communities, for example, hospitals are run by a few private firms or a semi-public non-profit, and have substantial market power. Overall, the U.S. spends a much higher percentage of GDP on health care than other industrialized countries, where nearly everyone is covered. Even with Obamacare efforts to contain costs, projections by Medicare and Medicare actuaries—hardly a group with a political axe to grind—indicate this disparity will continue to increase. European nations and Japan better contain costs, and many provide arguably more effective care, by recognizing that the market for health services is not a place where competition effectively contains costs. Germany sets prices for new drugs according to how much those improve treatment over existing medicines. That system doesn't let Big Pharma drum up sales for new incontinence drugs by pushing old folks watching daytime TV to rush to CVS, then bill Medicare whatever it pleases. Curbing market and patient manipulation is where the future lies. Liberal Democrats see Obamacare as the road to paradise—socialized medicine like the British system—but the really effective systems like those in Germany rein in private prices, salaries and excessive staffing. Regulation is painfully distasteful to conservative Republicans, but it would be a whole lot better than a National Health Service run like the Postal Service, or worse, the IRS. Reshaping Obamacare to bring down costs and premiums would capture voter loyalty more effectively than advocating the impossible—repealing the law altogether. If Republicans don't move in that direction, Hilary Clinton, who is shrewder than her liberal base, surely will and marginalize the GOP for a generation. Peter Morici, an economist and professor at the University of Maryland Robert H. Smith School of Business, is a widely published columnist. He tweets @pmorici1 |


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Sunday, March 01, 2009
Double-blind reviewing
My primary concern against double-blind reviewing is what restrictions is puts on author dissemination. I have limited experience with double-blind reviewing as an author, and my impression was that authors were not to disseminate their work in any public way when submitting to a conference with double-blind reviewing. Perhaps times have changed, or my memory/understanding was faulty, but such strict dissemination restrictions do not seem to be the default.
For SIGCOMM (which is double-blind) the important statements in the call seem to be:
"As an author, you are required to make a good faith effort to preserve the anonymity of your submission..."
but at the same time,
"The requirement for anonymity is not meant to extend beyond the submission process to the detriment of your research. In particular, you may circulate your submission among colleagues or discuss it on a mailing list if you see fit. "
I wish this second statement was clearer, but my understanding (and apparently the understanding of at least some others) is this wouldn't prevent an author from putting the paper on their web page or on arxiv or giving a talk somewhere about it.
If we have this understanding, we should move to double-blind reviewing. To try to limit myself to something new in the argument -- again, go read Sorelle's post and comments! as a baseline -- let me say that after serving as a PC chair, it's absolutely clear to me that biases based on the authors' names do regularly enter into the picture. Let me take a hypothetical situation. Three initial reviewers give bad reviews to a paper. Another PC member takes a look -- because they know the author -- and argues that they've heard a bit about the work, that the reviewers might not realize how this is tying together two areas (quantum and e-commerce auctions! -- again, that's hypothetical) in a novel way, and think an outside reviewer is in order.
At this point, bias has almost surely entered the picture -- unless you think with high probability the other PC member would have noticed this paper without the name on it. It's a limited and seemingly harmless entry of bias -- all that's being asked is someone else look at the paper! -- but what about all the other papers that aren't going to get a second (well, fourth) look because the "right person's" name isn't on the paper? In my mind, it's bias pure and simple. At this point, it seems to me, if you want to argue against double-blind reviewing you have to argue that the cost of this solution is outweighed by the actual benefit. (Hence my concern about the "costs" of limiting authors' ability to disseminate -- which for now I'm understanding is a less severe issue than I might have originally thought.)
And by the way, I think there are much more severe examples of bias that regularly come to play in PC meetings. Much of this readily admitted, by people who give the argument that we in fact should give more trust to "name" authors that unknown authors, since they have a potentially bigger loss of reputation to protect. (See comments at Sorelle's page for those that give this argument.) People presenting this argument are at least being open that in their mind they are considreing a cost-benefit analysis on the bias they admit is there. I don't think this argument holds up -- though we can leave that discussion for the comments if needed.
To wrap up, I should say that I personally don't recall a setting where I thought there was specific bias against female authors in a theory PC, which was an issue Sorelle brought up. I'm not saying it doesn't exist, but that unlike many other clear issues of bias that I have seen, I can't recall a specific one where I felt sexism was playing a role. Of course that doesn't change my opinion that double-blind reviewing, implemented suitably, would be of positive benefit for our major conferences. And if there is bias against female authors, an additional benefit is it would likely mitigate that as well.
25 comments:
While we're discussing potential imports from system conferences to theory conferences, allow me to mention: rebuttals. It can be quite annoying when a reviewer claims that technique X from some paper he read a while back already solved your problem (or some non-trivial part of it) and therefore gives you a bad review, when actually X fundamentally doesn't work in the current setting. You could say that the authors should explain why previous approaches don't work, but it requires (infinitely?) more pages to explain why "for all previously known X, X doesn't work here" vs. "we give a Y that works", and even if you make an attempt at arguing the coNP statement, it won't help if you don't manage to mention the particular X which the reviewer had in mind!
- March 1, 2009 at 3:15 PM
Wrt bias against female authors, in my PC experience I have often noticed that a single female authored paper that is borderline tends to be "torn apart" in the reviews. I have never seen an instance when such a paper was rejected when I thought the paper should be accepted, but the reviews seemed to be much more negative than other borderline rejected papers.
- March 1, 2009 at 4:56 PM
- JeffE said...
I'm exactly backwards on the fame-bias axis; I always encourage reviewers to be harder on famous names, not easier. Well-known authors have more responsibility to make the paper stand on its own merits -- they, more than anyone else, understand (or even define) the community standards. It's the newer authors, especially students, who should be given the benefit of the doubt in borderline cases.
Perhaps that's an argument that I should only be given anonymous papers to review. <shrug/>
Yes, anonymous #1, it is the author's responsibility to explain why previous techniques don't work. Yeah, that means more work. So what? - March 1, 2009 at 4:58 PM
- Yuriy said...
How can a paper be a borderline reject if the reviews "tear it apart"? Is the paper of excellent quality but the reviews are terrible and thus it is judged to be a borderline paper? Or are you using some metric other than the reviews to decide that the paper is borderline?
- March 1, 2009 at 5:01 PM
Yes, anonymous #1, it is the author's responsibility to explain why previous techniques don't work. Yeah, that means more work. So what?
Yes, but which previous techniques? If I'm writing a paper in area A, and the reviewer conjures up some random technique from area B which he thinks would solve our problem, and he's wrong, then what? What I'm saying is, even if you make a good faith effort to discuss previous techniques, it is not possible to explain why "for all previous techniques X, X doesn't work here". It may be possible to explain why "for all previous techniques X for related problems, X doesn't work here", but that's not what I'm discussing.
Anyway, the short story: people make mistakes, including reviewers, so I think it makes sense to allow rebuttals to deal with the cases when reviewers goof (after all, we already have reviewers to deal with the case when authors goof up!). Delaying a paper's visibility for half a year because of one human error doesn't make sense when there's an easy way to avoid that error (rebuttals). - March 1, 2009 at 6:37 PM
- Michael Mitzenmacher said...
I think it's off-topic, but regarding rebuttals -- anon #5 claims rebuttals are an "easy way" to avoid errors. I think they're so rarely used precisely because that's not actually the case. At a high level, rebuttals increases the number of rounds of communication from 1 to 2. Rounds of communication are expensive, in terms of time delay. They also serve as a forcing function (it makes no sense to have rebuttals if you don't have all the reviews) in a setting where, quite frankly, many PC members are not good at meeting deadlines.
Again, we discuss rebuttals in terms of cost-benefits. But your assumption that the cost is low seems way off base as a starting point. - March 1, 2009 at 8:54 PM
Re the cost of rebuttals: along with the cost to PC members that MM mentions, there's also a cost to submitters: all must be prepared to set aside a day of time to prepare a rebuttal, usually at very short notice. And all authors will feel obliged to defend their paper against whatever criticism they see in the initial review. The number of people who end up preparing rebuttals is far greater than the number of cases in which a genuine error in a review is found and corrected.
As for the "why doesn't technique X solve this problem more easily" type criticisms, they are difficult to answer even when the criticism is misguided. The critiques of this form usually don't provide enough detail to determine exactly what the reviewer means, and it may take more time than provided in the rebuttal process to answer questions like that. If it was an obvious technique to try, the authors should have already addressed it in their paper, and if it wasn't obvious then the possibility that it works shouldn't be very critical. - March 1, 2009 at 10:03 PM
Though I have submitted papers to conferences with double-blind reviewing I have never been on a PC for one.
One item, which has come up on almost every PC I have served on, is the question of closely-related papers that solve very similar problems or use some common idea. If there are several such papers by disjoint sets of authors, should one treat them differently from the same papers with the same authors or largely overlapping sets of authors? I believe so.
Do any conferences PC you have been involved in that use double-blind reviewing do hashes of author names or some other method for the PC to resolve such issues should the need arise? - March 1, 2009 at 10:27 PM
We already have a system for rebuttals: Good conferences spread throughout the year.
You can write your rebuttal in our resubmission. Theory is not like many CS fields where there is only one major annual conference. - March 1, 2009 at 10:31 PM
- Lev Reyzin said...
I'm not against double-blind reviewing, but here's a strange possible objection that I haven't seen brought up: I'm guessing some people would think twice before sending a marginal paper to a good conference, partly because it may damage their reputation to spam conferences with bad papers. When reviewing is anonymous, there's less incentive to refrain from sending bad papers on the hope they by chance get in. I wonder if this would increase the number of submissions and place more burden of conference PCs. The statistics are probably out there for conferences that switched to double blind reviewing in recent years...
- March 2, 2009 at 9:41 PM
I hadn't thought of Lev's objection, but I really like it. I don't know how much of an effect there would be in the real world, but certainly it demonstrates how difficult it is to predict the effects of a change.
How about adding more openness, rather than more secrecy? Right now there's not much accountability for the PC, since few outsiders know which papers were rejected.
Suppose all submissions were required to be made public at the time of submission, for example on the arXiv or ECCC, and suppose that the fact of submission were also public. Then anybody who cared could form their own opinion of the decisions, and the PC would know that any biases or mistakes would be visible to everyone. - March 2, 2009 at 10:46 PM
- Michael Mitzenmacher said...
Anon #11 (and Lev): I'm certainly willing to yield that the Law of Unintended Consequences could take effect. If someone were to try this, it would be nice to have some post-analysis afterward. (I tried to offer post-analysis for the stuff I tried as PC chair; but it's clear not everyone necessarily agreed with my post-analysis.)
However, I think bad authors already send in bad papers. Good authors ostensibly avoid sending in bad papers on the off chance they'll get in (with either system) because it would damage their reputation to have them accepted! I don't see people associating much cost to sending in what end up being judged "less-good" papers currently.
That being said, you both certainly have a valid and interesting point. Thanks! - March 2, 2009 at 11:01 PM
- Unknown said...
As someone pointed out in comments in one of the blog posts about this (I forget who and where), there are two general classes of arguments against DBR:
1) The author list has little influence on acceptance currently so it's not worth the trouble
2) The author list has a significant influence currently, and that's a good thing.
I don't know how to reply to viewpoint #2. Regarding viewpoint #1, the only way to really determine if author names matter is to run a controlled experiment. Here's how I'd imagine such an experiment working.
1) Authors submit two versions of their submission PDF, one with author names and one without. They also submit some information that is hidden from the PC but used for experimental evaluation:
* the max, over all authors X, of the number of papers X published in STOC or FOCS in the past 10 years
* How many authors are from [list of 10 institutions that publish the most in STOC and FOCS]
* Whether an author has won a Godel prize or Turing award
* A guess as to the score the paper will receive
* Gender and ethnicity of the authors
2) Papers are randomly assigned to either an anonymous group or an eponymous group. The author-provided information can perhaps be used to cluster the population, reducing the noise inherent in random sampling.
3) The PC deliberates on the eponymous papers in the traditional manner using the eponymous PDFs and selects 50 eponymous papers for definite presentation and 15 alternates.
4) The PC deliberates on the anonymous papers using the anonymous PDFs and double-blind procedures. The PC selects 50 papers from this group for definite presentation and 15 alternates
5) The PC is told the authors of the borderline papers in the anonymous group of alternates. The PC then selects an additional 15 papers for presentation from among the alternates.
1) The number of papers that "should be accepted" that are assigned to the anonymous group is a random variable with mean 50 and standard deviation around sqrt(50) = 7. The "alternates" are designed to correct for this, so if the null hypothesis that names are irrelevant is true then this experiment should not affect which papers are accepted.
2) To analyze the data, compare the fraction of papers with (for example) big-name authors that get accepted in the anonymous and other track.
3) With so many possible correlations and so little data, there's a risk of testing 20 hypotheses and getting 1 true by chance. Therefore we might need to run two experiments, one to develop specific hypotheses and a second to test them. Fortunately the overhead is relatively low (30% perhaps?), so while this isn't trivial it's not impossible either.
4) Is anyone reading this an expert in design and analysis of experiments of this sort? To my knowledge no controlled experiment has been done before that measures bias throughout a real PC process, not just the opinions of undergrads taking an intro to psychology class. One might therefore interest a social scientist in helping with this experiment. - March 3, 2009 at 7:25 PM
To my knowledge no controlled experiment has been done before that measures bias throughout a real PC process, not just the opinions of undergrads taking an intro to psychology class.
It's almost impossible to do a proper controlled experiment for phenomena like this. One key problem is that the experimental half-anonymous process isn't really the same as either process done in isolation. For example, suppose no statistical difference shows up. That could be because single-blind reviewing is in fact unbiased, or it could be because participating in the new process sensitized PC members to the issues and changed their behavior even in the non-anonymous half. One can make up lots of stories of this sort, some admittedly less likely than others, going in either direction. The net effect is that it's just not worth the effort of running the experiment when the results couldn't be considered in any way definitive. (Plus there's the issue that even relatively small effects, involving only a handful of papers in a typical conference, could be important here but are difficult to detect in a small experiment.)
In general, experimental results can be seriously biased if anybody involved even knows they are participating in an experiment. For example, this comes up often in education reform: it appears that merely trying something new and experimental (regardless of what it is) is exciting and motivational and causes gains that don't necessarily survive beyond the experimental stage.
The best experiment I've thought of regarding academic evaluation could be carried out beautifully by the NSF. NSF review panels are somewhat secretive (word of who is on them may leak out but doesn't become widely known) and rank lots of grant proposals without consulting anyone off the panel. They could easily invite two panels to review exactly the same proposals, and probably nobody would find out until after everything was over. It would be fascinating to see how different the two rankings turned out to be. It would also be interesting to see what sorts of factors (gender, prestige, seniority) were correlated with disagreement between the panels. - March 3, 2009 at 8:59 PM
But NSF panel judgements are based on info about the applicant like CV, are they not?
I think judging NSF panels is very different from judging papers. Why can't we just run DBR for a major conference in 2010 and see what happens? - March 3, 2009 at 9:12 PM
- Unknown said...
Dear Anonymous March 3, 2009 8:59 PM:
Of course my experimental design is imperfect. The question to ask is not whether this experiment would be "definitive", but whether it would improve our knowledge of bias in TCS reviewing more than any other study of the same cost. Can you supplement your criticisms of my proposal with a proposal of a better way to get data? I can think of several alternative ways to study bias in TCS reviewing, but they all have even worse issues than the one you mentioned IMHO. For example:
1) There's plenty of anecdotal evidence of bias or lack thereof, but anecdotes are an especially poor methodology for studying unconscious bias! Without an alternate experimental proposal you are in effect arguing that anecdotal evidence is the best we can do.
2) One could try to deduce something from a comparison of math journals with and without DBR, replicating a previous study of that sort in Ecology. The flaws with such an approach include the confounding factors inherent in a non-controlled study and the possibility that math and TCS may have different levels of bias.
3) One could run an entire TCS conference double-blind and then compare to a comparable single-blind conference, but:
* people would know that double-blind was an experiment so the results would still be distorted by the effects you mention
* The non-random assignment of papers to the two conferences would make analysis trickier. - March 3, 2009 at 9:53 PM
But NSF panel judgements are based on info about the applicant like CV, are they not?
I think judging NSF panels is very different from judging papers.
Definitely, that experiment is to answer a very different question (and has nothing to do with double-blind reviewing). It's just a tangent.
Why can't we just run DBR for a major conference in 2010 and see what happens?
What do you expect will happen? Some people will love it and will get terribly excited. Some will hate it and will complain bitterly about it. Very few people will decide that the experience has changed their opinion. There will be huge debates about what the effects were, if any, since in any given conference they are sure to be small enough to be debatable. In the end, we'll have to make the same decision with very little useful information gained, while both sides triumphantly claim that all their beliefs have been validated.
This is like a lot of government policy decisions (should we lower taxes, etc.). There are enough variables that it is hard to convince people by trying an experiment, while lots of people will view any experiment as a precedent. - March 3, 2009 at 10:04 PM
Make FOCS have DBR and STOC not. Run for five years. See what happens.
- March 3, 2009 at 10:15 PM
Without an alternate experimental proposal you are in effect arguing that anecdotal evidence is the best we can do.
I'm arguing that I can't think of any practical experiment in this area that I consider likely to change many people's minds or to be worth the trouble of trying.
One could try to deduce something from a comparison of math journals with and without DBR, replicating a previous study of that sort in Ecology.
I don't know of any math journals that currently use double-blind reviewing. I'm told that some have experimented with it in the past but have given it up. I couldn't find any good web references, beyond vague references like this one:
Hearsay like this suggests the experiments in mathematics journal were considered failures, but I don't know anything about them. Does anybody know more? - March 3, 2009 at 10:19 PM
Make FOCS have DBR and STOC not. Run for five years. See what happens.
What could we learn? Suppose FOCS ends up with measurably more papers from marginalized groups. Maybe those people were just sending their better papers to FOCS. Even if overall submission rates don't change, the better or worse papers may be getting shuffled between the two conferences, and there's no way to tell how much of a role the actual blinding played. (This is what Warren was addressing by randomizing things within a single conference.)
In fact, I suspect that this experiment would end with accusations that people were deliberately biasing the results in this way, by sending their best papers to their favorite conference, not because they really expected the review process would make a big difference for them, but rather to cast a vote in favor of the system they liked. And it wouldn't even be a fair vote, since each side could accuse the other of "voting" more vigorously. - March 3, 2009 at 10:32 PM
"I'm arguing that I can't think of any practical experiment in this area that I consider likely to change many people's minds or to be worth the trouble of trying."
How do you know that Warren's suggestion wouldn't change someone's mind? Why do you use this dismissive tone as if nothing can be done?
The fact is that alot of people think that something can be done to make the system fairer or convince people that it is. Whether or not it is "trouble" to run an experiment is for everyone to decide. We should take some sort of organized vote (like when people vote for SIGACT officers). - March 3, 2009 at 10:33 PM
Wow, no wonder you people are theoretical computer scientists. If you ran a real computational experiment and it didn't give you the answer right away, you'd just argue that no experiment could ever give you the answer.
I really think if we ran Warren's experiment, it's very likely we could discover something unexpected, perhaps good, perhaps bad, but definitely useful. - March 3, 2009 at 10:38 PM
- Unknown said...
Something similar to giving two NSF panels the same proposals has apparently been done before. See "Chance and consensus in peer review" by
S Cole, Cole JR, and GA Simon in Science, Vol 214, Issue 4523, 881-886
abstract and full text - March 3, 2009 at 11:32 PM
Something similar to giving two NSF panels the same proposals has apparently been done before. See "Chance and consensus in peer review" by S Cole, Cole JR, and GA Simon in Science, Vol 214, Issue 4523, 881-886
Great, that's really interesting and somewhat depressing (about 25% of decisions would have been different given different reviewers). The paper actually predates the panel system and involved mail review instead. I wonder whether panel review increases or decreases the instability.
If you ran a real computational experiment and it didn't give you the answer right away, you'd just argue that no experiment could ever give you the answer.
This is different - it's more of a social/emotional issue than a statistical issue. People have been publishing papers comparing double-blind and single-blind reviewing for decades, but the process hasn't converged to a consensus and I don't expect it ever will. The evidence is always problematic, the people involved always have an agenda, and nobody can give any principled estimate for just how bad the evidence is because it depends on too many unknowables. Lots of people have their beliefs reinforced by the statistics but very few people change their minds. Without some powerful new idea (which I don't think exists), we won't be able to settle the issue by real-world statistical evidence and we'll just have to fall back on judgement and gut feelings. Warren's approach is much better than the analyses I've read in the literature, but I still don't think it will be anywhere near decisive.
The fact is that alot of people think that something can be done to make the system fairer or convince people that it is. Whether or not it is "trouble" to run an experiment is for everyone to decide. We should take some sort of organized vote (like when people vote for SIGACT officers).
Community-wide direct democracy is tricky (who gets to decide what to hold a vote on?). One possibility is to put pressure on the organizations that run your favorite conferences. If you want double-blind reviewing, I don't think FOCS/STOC is the right place to start. I'd pick a somewhat less prestigious conference that may view a superior reviewing process as a competitive advantage vs. the top conferences. This may arouse less resistance than starting at the top, too. At the very least, this approach will give a chance to gather evidence and get people more comfortable with the whole process; you can then use that experience as an argument for extending it to more conferences, if it works out well. (I don't think the evidence will prove compelling, but the increased comfort level might.) In the best case scenario, the reviewing process will work markedly better and the conference will start to attract some really excellent papers, which will certainly make FOCS/STOC take notice and change their ways.
There's also the approach of starting a new conference with very high standards and double-blind reviewing. That's hard to pull off well, but it would be doing the community a real service. Double-blind reviewing might be a good hook to get people involved, since it seems to create a lot of interest. I'm actually serious about this - I don't want double-blind reviewing, but I do want more first-rate conferences (FOCS/STOC dominance is a bad thing) and psychologically it's easier to set the bar high for a new conference than to raise it for an old one. Double-blind reviewing may be what it takes to raise enough interest to get a new conference off the ground. - March 4, 2009 at 12:59 AM
- Unknown said...
If you want double-blind reviewing, I don't think FOCS/STOC is the right place to start.
I disagree because:
1) It is quite plausible that there might be a big name effect in top conferences but not in secondary ones (or vice versa). We need to run the experiment that answers the question we really care about, which is bias in FOCS/STOC.
2) FOCS and STOC are quite broad, forcing lots of tricky apples to oranges comparisons by a PC that is not completely expert, which is a great opportunity for bias. More narrow conferences have a more focused PC compare similar papers, making objective decisions easier.
There's also the approach of starting a new conference with very high standards and double-blind reviewing.
In algorithms at least there are three major conferences spaced pretty evenly throughout the year (FOCS/STOC/SODA). I doubt there's room in the year for another conference of comparable prestige. When would you put its submission deadline? Perhaps one could move the STOC deadline to October and then have a new conference deadline in January. - March 4, 2009 at 10:52 AM


text:
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text:
{photo via Martha Stewart Weddings}
I am really liking the up and coming trend of candy cakes, especially a cake decked out in M&MS! The decorating options are endless and it looks good in every color scheme imaginable! I have a few ideas myself and I would love the opportunity to try them out. My only question though is...would people actually enjoy eating a cake with an entire candy layer (taste and texture)? I LOVE cake and my favorite part is the icing. I'm not sure if I would like the crunch addition??
Weekly Round Up
Breakfast and brunch is my favorite meal, so I was smitten with this Eggs Benedict Bar shown on Celebrations at Home.
I was blown away by the styling of this Bb is for Baby Shower on Bump Smitten.
This strawberry inspired bridal shower is just gorgeous. LOVE the pops of turquoise!
Are you familiar with washi tape?! I really want to place an order and get creative!
In case you missed seeing the pictures of a recent client party, here is write up.


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8 Jul, 2017
Second Global Cybersecurity Index launched
United Nations, (UN News Centre) 5 July 2017 – Only about half of all countries have a cybersecurity strategy or are in the process of developing one, the United Nations telecommunications agency today reported, urging more countries to consider national policies to protect against cybercrime.
Releasing its second Global Cybersecurity Index (GCI), the International Telecommunication Union (ITU) said about 38 per cent of countries have a published cybersecurity strategy and an additional 12 per cent of governments are in the process of developing one.
The agency said more effort is needed in this critical area, particularly since it conveys that governments consider digital risks high priority.
"Cybersecurity is an ecosystem where laws, organizations, skills, cooperation and technical implementation need to be in harmony to be most effective," stated the report, adding that cybersecurity is "becoming more and more relevant in the minds of countries' decision makers."
The top 10 most committed countries include three from Asia and the Pacific, two each from Europe and the Americas, and one from Africa, the Arab States, and the Commonwealth of Independent States.
They are, in order: Singapore, United States, Malaysia, Oman, Estonia, Mauritius, Australia, Georgia, France and Canada. Russia ranked 11th.
In addition to showing the overall cybersecurity commitment of ITU's 193 member States, the Index also shows the improvement and strengthening of the five pillars of the ITU Global Cybersecurity Agenda: legal, technical, organizational, capacity building and international cooperation.
The threat is particularly worrying as in 2016, according to ITU, nearly one per cent of all emails sent were essentially malicious attacks, the highest rate in recent years.
Last month, a cyberattack crippled tens of thousands of machines around the world. It is unclear who was behind the attack.
"While the impact generated by cyberattacks, such as those carried out as recently as 27 June 2017, may not be eliminated completely, prevention and mitigation measures to reduce the risks posed by cyber-related threats can and should always be put in place," said ITU Secretary-General Houlin Zhao.
The findings show that there is "space for further improvement in cooperation" at all levels, according to the report, which advocates for encouraging governments to consider national policies that take into account cybersecurity and encourage private citizens to make smart decisions online.


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Lyrics Depot is your source of lyrics to Pimp Slapp'd by Snoop Dogg. Please check back for more Snoop Dogg lyrics.
Pimp Slapp'd Lyrics
Artist: Snoop Dogg
Album: Paid Tha Cost to be Da Bo$$
[DJ E-Z Dick]
W-Balls, it's your main man DJ E-Z Dick
About to unleash another one of those platnum plus hits
And the word is on the streets, and the word is the streets
We gon go to a live remote, licking wit my main man Mr Doggy Dogg
[Snoop Dogg]
A day in the life, of a Rollin 20 Crip
I'm just a stuburn type of fella with a head like a brick
And just because I sip Moet, they say that I'm hopeless
But I don't give a fuck, so blame it on the loc'ness
Now this is how we do it when we checking the grip
Snoop Dogg is in this bitch, so don't even trip
I bust a funky composition that's smooth as a prism
Now check it as I kick off in this funky ass rhythm
It's six dub, the phone is ringing off the deck
And it's some homies talking about I disrespected they set
Aww nah, Dogg aint this y'all
I got couple relatives up off of Crenshaw
This is about me and Simon, not me and y'all
I got love for a bunch of real B-Dogs
Like K-Dub, Top Cat, B-Reel, E-Rock, Boo-Lay Face
And the homie Har'ron rest in peace
Big Jay from Cappinella Park
He used to blaze with his nephew after dark
On and on, rocking big neck bone
Mausberg I had to put you on my song
It's so real, I had to show some love
Now back to this scrub, it ain't about Crip or Blood
It's about you bein jealous of what I does
Cause I does it the most, the king of the coast
in the paint playin post - I back you down
like Shaq-Daddy, and bust on ya out the new Caddy
And skirt up, bust ya boulevard
I'm not Xzibit, you can't +Pull My Hoe Card+
.. I fucked all your groupies
When you was doin time in Camp Snoopy
With the fags and snitches, no killers just bitches
And you was payin niggaz off with all my riches
You so hardco', why you ain't go to level fo'?
Oh I know (bitch!)
But I walk the mainline everytime I go down
You can check my G files I do it L.B.C. style
.. I got the word on your Simon
You need to just start rhymin
Cause you the biggest star on your label
And them other niggaz just crumbs off my table
You're not able, to compete with the heat that I drop
And I still ain't been paid, for "1-8-7 on a cop"
I started yo' shit and I will end yo' shit
if you keep talkin shit on Crip!
[Hook 1: repeat 2X]
It all boils down to the fact
that you're jealous of my paper stack (jealous ass nigga)
It all boils down to the fact
that you're jealous of my paper stack (gon get pimp slapped)
[Hook 2: repeat 2X]
Money, I get it, paper I got it
Heaters, I keep em, bitches I got em
[Snoop Dogg]
If I shoot you, I'll be brainless, and you'll be famous
And I'll be spending money out the anus
Your only gain is to try to get me to fall down to your level
Man you worser than devils
Alotta niggas should've said it, fuck em
But Ima say it for em, stop it, pop it, rewind and play it for em
This nigga's a bitch like his wife
Suge Knight's a bitch, and that's on my life
And I'ma let the whole world see
Cos you fucked up the industry, and that's on me
We can go head up, nigga, set it up
Or we can do the other thing, I love to wet it up
Your rappers and artists, tell em, shut it up
Cos I'll fuck every last one of em up, especially Kurupt
See that's my lil homeboy, so he knows what's up
He better keep it Crippin, and slip his clip in
Cos these niggas trippin, this is official business
Do the same way, leave no witnesses
This is that unexpected diss directed, sprayed, covered and protected
Strip you butt naked, chicky-check-check-it
It's all to the good again
You can catch Snoopy Dibby Double in the hood again
Spinning that real times, spitting that real shit
To make the whole world feel it
So put the bacon in the skillet, and try to peel it
Cause Doggystyle Records is the realest, nigga
[Hook 1]
Money, I get it, paper I got it
Heaters, I keep em, bitches I got em
Money, I get it, paper I got it
Jealous ass nigga
Snoop Dogg Lyrics
Snoop Dogg Paid Tha Cost to be Da Bo$$ Lyrics
More Snoop Dogg Music Lyrics:
Snoop Dogg - Bring it On Lyrics
Snoop Dogg - Buck 'Em Lyrics
Snoop Dogg - Dogghouse Lyrics
Snoop Dogg - Gangsta Ride Lyrics
Snoop Dogg - Gold Rush Lyrics
Snoop Dogg - Hit Rocks Lyrics
Snoop Dogg - Real Talk Lyrics
Snoop Dogg - You Got What I Want Lyrics


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Eggless & Crunchy Chocolate Chip Cookies
Ever since I bought this book last year, I have been doing a lot of baking at home.... Thanx to the book, I'm not scared to bake anymore!! :) This crunchy cookie recipe is also adapted from the same book. A lot of Mane Adige readers have been mailing and asking me to post more eggless recipes. So, here goes!!
Meanwhile, I have less than a week left before my parents arrive... I am soooo excited!!!! And also a little scared... I hope the swine flu issue does not create any problems during their travel... I also have a lot of minor preparations to make, for their arrival. And these terrible rains and cold weather is not helping in any way :((.... Will keep you guys posted! Hope y'all like the cookies....
1/2 cup Butter at room temperature
3/4 cup Sugar OR 1/2 cup brown sugar+ 1/4 cup sugar
1.5 cups All Purpose Flour/ Maida
1 tsp Baking soda
2 tsp Vanilla extract
3 tbsp Cooking oil
1/2 cup Chopped nuts (optional)
1 cup Semisweet Chocolate Pieces
1/2 cup Shredded coconut (optional)
- Pre-heat oven to 350 deg F.
- In a large bowl, cream the butter and sugar until fluffy - approx. 2 minutes. If you are using electric mixer, set the speed to medium.
- Slowly add the flour, baking soda, vanilla, oil and mix until completely combined. Note: For a flatter cookie, or if the batter is too dry, add a couple of spoons of water.
- Add the chocolate chips, nuts, coconut and mix gently with a wooden spoon. Adjust the quantity of chocolate chips according to your wish.
- Drop by rounded teaspoonfuls on ungreased cookie sheets, spaced 2 inches apart; Bake for 8-10 mins or until the cookies are completely done.
- Remove from oven and let cool completely. Serve with milk or as is and relish!
Prep Time: About 35-45 mins;
Makes: About 20-25 cookies;


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A mixed team from ENS / CNRS / CEA-Saclay (SPEC) of the Pierre Aigrain Laboratory has for the first time highlighted the remarkable behavior of an electronic circuit when its miniaturization is extreme. These results are published in the journal Science. Researchers have shown that the basic laws of electricity, established since 1845, can no longer describe the properties of an electronic circuit when its dimensions reach the nanometer scale. These studies confirm the theoretical predictions of Markus Büttiker (University of Geneva) stated more than ten years ago and never checked.
For more information: the joint press release CEA-CNRS (in french).
The associated publicaiton: Violation of Kirchhoff's laws for a coherent RC circuit, J. Gabelli et al., ScienceXpress (2006) 1126940.
The Nano-électronique team of DRECAM/SPEC and the "Physique mésoscopique et transport" team of LPA.


text:
A standard CACHEBOX support package is packed with features to make your life easier and keep your cache performance high despite constant changes to internet traffic:
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- Low-cost hardware refresh. When your appliance reaches 4 or 5 years old, you can simply replace the hardware with a new unit at a discounted hardware-only price. So you can extend the life of your solution for 5 more years at a fraction of the cost of a new one.
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How a Forgotten '90s Soda Became a Recurring Gag on 'Loki'
Just two episodes in, Loki has already drawn us into its perplexing, utterly bizarre world. The Time Variance Authority has a familiar yet troubling feel, a purgatory-like space where time seems to have no meaning. Loki (Tom Hiddleston) finds himself trapped in the bureaucratic headquarters of the Time Keepers, where every worker is occupied with keeping the Sacred Timeline on track. There, he meets the sympathetic Mobius (Owen Wilson), a TVA agent with a penchant for jet skis and ... Josta?
Agent Mobius is seen chugging the unusual drink in the first and second episodes of the series, which causes us to wonder if his favorite beverage reveals anything about his character. As it turns out, Josta soda was a real product back in the 1990s, a failed PepsiCo creation that was only on shelves for a few short years. Launching in 1995, Josta was the first energy drink produced by a major U.S. drink company. By 1999, it was gone for good. For a beverage that had such a short life on the Sacred Timeline, Agent Mobius seems to enjoy it a lot.
In addition to its fruity taste, Josta's key ingredient was guarana extract, which was derived from a caffeinated plant found in South America. Guarana has been used for hundreds of years as a stimulant, appetite suppressant, and aphrodisiac. However, PepsiCo branded Josta less as a miracle tonic and more as a party drink. The first ad campaign involved a series of elderly men reminiscing on their past, wishing they would have partied harder when they were younger. Josta's slogan? "Better do the good stuff now."
(You don't have to be a time traveler to drink Josta, either. Sometimes old cans show up and people try them.)
Maybe this ties into Mobius' hope for Loki to correct the Sacred Timeline, instead of continuing to cause chaos with no thought of the consequences. Maybe he literally wants Loki to "do the good stuff now." Or he could simply be indulging his nostalgia for a past era, one that flashed by all too quickly. Of course, there's one other possible explanation — he just really likes the taste.
New episodes of Loki arrive every Wednesday on Disney+.


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For all of her help with the Northshield Website.
Know all by these words that there in Our Kingdom there are many that serve quietly and possess a great many skills that enrich the dream we share. Elizabeth of Bright Sands has demonstrated such dedication and devotion through exceptional service. Therefore, We, Hagan and Eilis, King and Queen of Northshield are pleased to bestow upon her the award of the Cygnus on this 8th day of December A.S. 42 at Boar's Head in Our Barony of Caer Anterth Mawr.


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If you wish to contribute or participate in the discussions about articles you are invited to contact the Editor
SBAS Fundamentals
Fundamentals | |
Title | SBAS Fundamentals |
Edited by | GMV |
Level | Basic |
Year of Publication | 2011 |
A Satellite-based Augmentation System (SBAS) is a civil aviation safety-critical system that supports wide-area or regional augmentation – even continental scale - through the use of geostationary (GEO) satellites which broadcast the augmentation information.[1][2] A SBAS augments primary GNSS constellation(s) by providing GEO ranging, integrity and correction information. While the main goal of SBAS is to provide integrity assurance, it also increases the accuracy with position errors below 1 meter (1 sigma).
The ground infrastructure includes the accurately-surveyed sensor stations which receive the data from the primary GNSS satellites and a Processing Facility Center which computes integrity, corrections and GEO ranging data forming the SBAS signal-in-space (SIS). The SBAS GEO satellites relay the SIS to the SBAS users which determine their position and time information. For this, they use measurements and satellite positions both from the primary GNSS constellation(s) and the SBAS GEO satellites and apply the SBAS correction data and its integrity.
The augmentation information provided by SBAS covers corrections and integrity for satellite position errors, satellite clock/time errors and errors induced by the estimation of the delay of the signal while crossing the ionosphere. For the errors induced by the estimation of the delay caused by the troposphere and its integrity, the user applies a tropospheric delay model.
SBAS Signal
Every SBAS provides ranging signals transmitted by GEO satellites, differential corrections on the wide area and additional parameters aimed to guarantee the integrity of the GNSS user:
- GEO Ranging: transmission of GPS-like L1 signals from GEO satellites to augment the number of navigation satellites available to the users.
- Wide Area Differential (WAD): differential corrections to the existing GPS/GLONASS/GEO navigation services computed in a wide area to improve navigation services performance. This includes corrections to the satellite orbits and clocks, as well as information to estimate the delay suffered from the signal when it passes through the ionosphere.
- GNSS/Ground Integrity Channel (GIC): integrity information to inform about the availability of GPS/GLONASS/GEO safe navigation service.
The SBAS delivers to the user the corrections and integrity data as well as some ancillary information (timing, degradation parameters, etc.) through messages encoded in the signal. The specification of the SBAS message data format is contained in the ICAO SARPS Appendix B for the aspects related with the signal in space, as well as in the RTCA MOPS DO-229D for the minimum performance requirements applicable to the airborne SBAS receiver equipment. The format of the messages is thoroughly explained in the article The EGNOS SBAS Message Format Explained.
The SBAS satellite shall transmit a GPS-like L1 (1574.42 MHz) signal, modulated with a Coarse/Acquisition Pseudo-Random Noise (PRN) code. The SBAS L1 radiofrequency characteristics are:[3]
Parameter | Description |
Modulation | Bi-phase shift key (BPSK) modulated by a bit train comprising the PRN code and the SBAS data (modulo-2 sum). |
Bandwidth | L1 ±30.69 MHz. At least 95% of the broadcast power will be contained within the L1 ±12 MHz band. |
Ranging Codes | A PRN Code (Gold code) of 1 millisecond in length at a chipping rate of 1023 Kbps. |
SBAS Data | 500 symbols per second, module-2 modulated (250 effective bits per second) |
Power | Minimum power –131 dBm at 5 degrees elevation Maximum power –119,5 dBm |
A convolutional encoding of the bits is performed with the following parameters:
Code Parameter | Value |
Coding Rate | 1/2 |
Coding Scheme | Convolutional |
Constraint Length | 7 |
Generator Polynomials | G1 = 171(oct); G2 = 133(oct) |
Encoding Sequence | G1 then G2 |
Flush | No |
SBAS Performances
The SBAS performances are defined with respect to the level of service that the system is designed to provide. The main source for SBAS performances comes from civil aviation navigation safety requirements and they are different for each civil aviation operation.[3]
Typical Operation | Horizontal Accuracy (95%) | Vertical Accuracy (95%) | Integrity | Time-To-Alert (TTA) | Continuity | Availability |
En-route | 3.7 km (2.0 NM) | N/A | 1 – 1 × 10-7/h | 5 min | 1 – 1 × 10-4/h to 1 – 1 × 10-8/h | 0.99 to 0.99999 |
En-route Terminal | 0.74 km (0.4 NM) | N/A | 1 – 1 × 10-7/h | 15 s | 1 – 1 × 10-4/h to 1 – 1 × 10-8/h | 0.99 to 0.99999 |
Initial approach, Intermediate approach, Non-precision approach (NPA), Departure | 220 m (720 ft) | N/A | 1 –1x10-7/h | 10 s | 1 – 1x10-4/h to 1 – 1x10-8/h | 0.99 to 0.99999 |
Approach operations with vertical guidance (APV-I) | 16 m (52 ft) | 20 m (66 ft) | 1 – 2 × 10-7 per approach | 10 s | 1 – 8 × 10-6 in any 15 s | 0.99 to 0.99999 |
Approach operations with vertical guidance (APV-II) | 16 m (52 ft) | 8 m (26 ft) | 1 – 2 × 10-7 per approach | 6 s | 1 – 8 × 10-6 in any 15 s | 0.99 to 0.99999 |
Category I precision Approach | 16 m (52 ft) | 6.0 m to 4.0 m (20 ft to 13 ft) | 1 – 2 × 10-7 per approach | 6 s | 1 – 8 × 10-6 in any 15 s | 0.99 to 0.99999 |
As indicated in the table above, the performance requirements are expressed in terms of four quantitative concepts, many of them to be interpreted as probabilistic figures:
- Accuracy: is expressed in terms of Navigation System Error (NSE) as the difference between the real position of the aircraft and the position provided by the airborne equipment. A SBAS assures the compliance with respect the accuracy requirements by providing to the user corrections to the satellite orbit and clock errors as well as to the ionospheric residual propagation error. For LPV200 operations, new requirements have been proposed distinguishing the fault-free and the system failure conditions.[4]
- Integrity: is defined by ICAO as a measure of the trust that can be placed in the correctness of the information supplied by the system.[3] This general statement is expressed at the SBAS system level as the maximum allowable probability that the navigation position error exceeds alarm limit and the navigation system does not alert the pilot in a time less than the time to alert. The SBAS assures the integrity requirements by:
- Providing to the user satellite and/or ionospheric alarms in order to inform the user to reject the corresponding satellite/ionospheric corrections in its positioning computation.
- Providing to the user Horizontal and Vertical Protection Level information (HPL, VPL) in order to assess the availability of the system, by comparing these PLs with the corresponding Alarm Limits (AL) for a given phase of flight (see next table). The SBAS computes and broadcasts integrity bounds to the satellite orbit and clock (UDRE) corrections as well as to the ionospheric corrections errors (GIVE) so that the user is able to compute a PL that over bounds the navigation system error experienced by the user with the integrity risk requirement.
Operation | Horizontal AL | Vertical AL |
En-route (oceanic/continental) | 7.4 Km (4 NM) | N/A |
En-route (continental) | 3.7 Km (2 NM) | N/A |
En-route, Terminal | 1.85 Km (1 NM) | N/A |
NPA | 556 m (0.3 NM) | N/A |
APV-I | 40 m (130 ft) | 50 m (164 ft) |
LPV200 | 40 m (130 ft) | 35 m (200 ft) |
APV-II | 40 m (130 ft) | 20 m (66 ft) |
Category I | 40 m (130 ft) | 15 to 10 m (50 ft to 33 ft) |
- Continuity: is the probability that the specified system performance will be maintained for the duration of a phase of operation, presuming that the system was available at the beginning of that phase of operation and was predicted to operate throughout the operation.[3] Lack of continuity means that the operation must be aborted (with the associated risk).
- Availability: is the probability that the navigation service is available at the beginning of the planned operation. A SBAS is considered available when the accuracy, integrity and continuity requirements are met and it is measured in terms of probability of the system being available for any given user at any given time. In practice, the availability is computed by measuring the probability of a protection level being below its corresponding alarm limit. It should be noted that a lack of availability is not a safety concern but prevents the nominal operation of the system, and implies an associated impact on the service operation status.
SBAS Architecture
A SBAS is a safety critical system designed to augment one or several satellite navigation systems. In this sense, it is not a standalone system. The main layers of a general SBAS architecture are:
- Space segment comprising the geostationary satellites (GEO) with navigation payloads in charge of transmitting a GPS-like carrier signal with the SBAS information.
- Ground segment comprising all the ground elements in charge of the provision of the SBAS navigation message. The main elements are:
- Monitoring Station Network.
- Processing Facility Center.
- GEO Satellite Control Center.
- Communication Layer.
- Support segment comprising all the elements need to support the correct operation and maintenance of the SBAS: configuration control, performance evaluation, maintenance and development, help desk, etc.
- User segment comprising all the user equipment needed to receive and use the SBAS information.
Space segment
The SBAS space segment is composed by several geostationary satellites in charge of broadcasting, over the service area, the SBAS navigation message. Typically, the SBAS satellites are multi-purpose (commercial communication) satellites that carry out an additional navigation payload capable to generate a GPS-like signal that retransmits to the users the navigation message generated on-ground.
The SBAS GEO navigation payload is a transponder that relays the on-ground generated signal (upload to the GEO in the C-band frequency) to a transmitted signal in the L-band frequency band. For most of the navigation payloads, a second C-band downlink channel is available in order to improve the adjustment of the signal delay due to atmospheric propagation. However, first generation of navigation payloads only included a single-channel frequency translating repeater.
The new generation of SBAS navigation payload includes more advanced functionalities. Among them, it is worth noting:
- Increase of the emission bandwidth and broadcast power.
- Evolution to dual-frequency L1/L5 transponders.
- Evolution of payload from signal transponders to regenerative payloads in which the signal is entirely build up onboard (the GEO only receives from ground segment the navigation message to be modulated in the GEO signal).
Ground Mission Segment
The main purpose of the Ground Mission Segment is to generate and uplink the augmentation signal that will be broadcast by the GEO satellite.
To achieve this objective, the Ground Mission Segment is typically broken down into the following subsystems:
- Monitoring Station Network: Its purpose is to collect data from the satellites that are to be augmented. This is performed by a network of GNSS receivers.
- Processing Facility Center: It is in charge of processing the data provided by the Monitoring Station Network to generate the messages to be broadcasted to the satellites.
- GEO Satellite Control Center: It is in charge of generating the signal with the message provided by the Processing Facility Center and up-linking it to the GEO satellites.
- Communication Layer: It interconnects the different elements of the Ground Segment.
Monitoring Station Network
The Monitoring Station Network is carefully designed to monitor satellites and ionosphere with the required accuracy and availability in the SBAS service area. This usually implies a dense network of stations in the service area, with some additional stations outside. In addition, there must be redundancy to avoid single points of failure, or even different subsets of stations to feed parallel and independent processing chains.
The monitoring stations have the following characteristics:
- Dual frequency (L1/L2) receivers with geodetic quality.
- Atomic frequency standard (Caesium/Rubidium/H-Maser).
- Able to track all in view GPS and GEO satellites.
- Allocated in site conditions with good local environment condition in terms of multipath and radio frequency interference .
- Geo-referenced to WGS-84 (or ITRF) within a 1-3 cm accuracy.
- Compliant with some processing capabilities:
- 1 Hz data acquisition.
- Embedded data quality checks to remove misleading data.
- Data processing and broadcast within a few milliseconds.
- Integrated robustness against known threats (e.g. evil waveforms detection).
Processing Facility Center
The Processing Facility Center is one of the critical elements of the SBAS system as it is charge of generating the augmentation information for the user, playing a major role in the achievement of the SBAS performance requirements.
The Processing Facility Center is in charge of the following functions:
- Process all input data from the Monitoring Station Network.
- Estimate the satellite corrections, ionospheric model and error variance terms.
- Perform a dedicated integrity assessment on the information provided by the system to the users.
- Format the outputs according to the SBAS standards.
The Processing Facility Center has a very strong algorithmic load, as it has to solve the following challenges:
- Advanced models for satellite orbit determination (breaking frontiers in GEO orbit and clock determination).
- Determination of the SBAS reference time and satellite clock corrections with better than 2 ns accuracy.
- Real-time ionospheric estimation with a dense network of receivers. This estimation should be able to characterize local and rapid phenomena.
- Integrity estimation valid for wide-areas with demanding performance requirements.
GEO Satellite Control Center
GEO Satellite Control Center function is to relay the SBAS messages computed by the Processing Facility Center to the GEO satellites. Its functions include:
- Codify the GPS-like signal encoding. In particular, the preparation of the signal generation as well as the PRN encoding.
- Modulate the SBAS message information provided by the Processing Facility Center into the signal.
- Synchronize the timing of the signal to the SBAS reference time.
- Control de time synchronization between the carrier and code components of the uplink signal (core-carrier coherency).
- Close the uplink-station/GEO-satellite control loop by receiving and processing the downlink SBAS satellite signals (both in L- and C- bands).
Communication Layer
The Communication Layer ensures that all the SBAS Ground Segment elements are interconnected in real time. This connection should be performed with high performance standards in terms of reliable lines, sufficient bandwidth for a large exchange of data, and stringent redundancy and security requirements.
Support Mission Segment
The SBAS Support Segment collects all the elements need to support the development and operation of a SBAS system. These elements are not related with the provision of the SBAS service but they are needed as external support facilities. They SBAS support needs can be listed as:
- The design, development and validation phases.
- The deployment and operation.
- The certification process.
- The maintenance and troubleshooting.
- The certification of applications.
Between the different SBAS Support elements it is worth noting:
- End to End Simulators in charge of simulating data under controlled conditions (reference errors, emulated feared events) in order to simulate the real system behaviour (delays and communication problems, algorithm, broadcasting features, etc).
- Service Volume Simulators in charge of evaluating the overall SBAS performances over the service area under a set of controlled conditions.
- Performance Analysis Tools in charge of measuring all the performance concepts at:
- system level by analyzing the Signal in Space information and checking the accuracy, integrity, continuity and availability features but using concepts based in the errors available at pseudorange domain.
- user point of view level, by analyzing user data (including local conditions) and applying user-related algorithms (see SBAS standards).
- On-line monitoring tools for tracking the system behavior in real time and collecting system failure and anomalies. These elements also support the system operation by predicting the expected behavior of the system and provide warnings as system outages or degradations. They also provide warnings to external users.
- Archiving tools supporting the data archiving. The data comprises both all the internal information generated by the system as well as external data (satellite reference orbit and clock data, ionospheric information, outages, etc).
- Application test benches to support applications by generating test scenarios for their certification and performance verification. They are able to plug different application software or equipment for homologation purposes.
User Segment
The SBAS user segment comprises all the user equipment that makes use of the SBAS Signal in Space (SIS). In fact, the SBAS User segment is not under the control of the SBAS service provider as it is driven by the SBAS application market.
In general, the SBAS service operator provides different services aiming at different market sectors, namely an Open Service, a Safety of Life service (SoL) and even a Commercial Service.
For the Safety-of-Life (SoL) service, the SBAS user equipment shall be compliant (certified) against several standards. For instance, civil aviation SBAS equipment shall demonstrate (see SBAS standards):
- Full compliance to RTCA SBAS MOPS DO-229 (airborne equipment).
- Full compliance to the RTCA SBAS MOPS 228 and 301 (antenna requirements).
- Compliance to RTCA TSO (C190, C145b, C146b) for SBAS equipment.
- Compatibility to other avionics equipment, in particular Flight Management Systems (FMS).
The SoL civil aviation certified equipment is in the highest rank with respect its cost. There exist a large number of certified receivers manufacturers worldwide both in the US (GARMIN, Honeywell, Rockwell Collins, General Avionics, etc) and in Europe (see complete list in EASA homepage[5]).
The Open Service (OS) targets low cost, general purpose GNSS equipment that uses the SBAS SIS to provide the user with an enhanced accuracy performance in comparison with the one provided by a standalone GPS device. In comparison with the certification requirements of the user equipment above, user equipment is not necessarily compliant with the RTCA MOPS DO 229 processing rules, but might only make use of the processing algorithms that render the accuracy corrections provided by the SBAS SIS.
Finally, some SBAS service providers (see EGNOS) include the provision of the information computed by the SBAS ground element (input raw data, corrections, integrity information) by dissemination means different to the SBAS GEO link (generally, using terrestrial telecommunication networks). This constitutes the Commercial Service. This market sector comprises professional users (land and geodesy applications, maritime or terrestrial transport applications) that are not subject to the integrity and latency requirements needed in the SoL service.
- ^ Wikipedia:GNSS augmentation
- ^ E.D. Kaplan, C.J. Hegarty, Understanding GPS Principles and Applications", 2nd Ed., Artch House, ISBN 1-58053-894-0, 2006.
- ^ a b c d ICAO Standards and Recommended Practices, Annex 10, Volume 1 Radio Navigation Aids, July 2006
- ^ NSP WGW October 2008 Report – Attachment G, Recommended changes to Annex 10, Volume 1, Section 3.7
- ^ List of ETSO Authorisations (European Aviation Safety Agency)