What’s A Cookie & What Does It Have To Do With My Privacy?

Most people know that there are cookies scattered all over the Internet, ready and willing to be eaten up by whoever can find them first. Wait, what? That can’t be right. Yes, there are cookies on the Internet (technically, the World Wide Web), and yes, they really are called “cookies”.  But they aren’t delicious and they can affect your privacy, so you should know what they do.

Whether you’re browsing Google search results, logging into Facebook, or just innocently chatting away on an online forum, you’ve encountered cookies. They aren’t inherently harmful but, just like passwords or email addresses, they can be exploited when placed in the wrong hands. Keep reading to learn how you can protect yourself.

What Are Cookies, Really?

In simple terms, cookies are just files that reside on your computer. Cookies are created when you visit a website. They are used to store bits of information about your interactions with the website, which the web server can use later when processing your sessions. The cookie is specific to you and it can be read by the web server (when interacting with it) or by programs on your computer.

To be technical, your browser is the program that mediates cookie control between your computer and the website. These cookies used by a website to present different types of content depending on who you are in relation to that website. Cookies can expire after a given time period (usually determined by the website issuing the cookie), but if necessary, they can be manually deleted.

Why are cookies used? Because they’re convenient and efficient. If a website wants to service thousands of users without cookies, it would have to store all of that interaction data in its own storage and it would have to be processed on its own. By offloading that work to the user, it becomes a faster and less strenuous procedure.

What are cookies used for? One reason for a cookie is to identify you. If you log in to a website and close your browser, then open it back up, the website knows it’s you because that cookie exists (it was created when you logged in). Cookies can store all sorts of information, like your preferences, your browser type, your location, etc. and this information can be used to better your experience.

How Do Cookies Affect You?

For the most part, cookies are NOT harmful. They’re just another protocol used on the Internet to facilitate communication between users and servers. Worried about viruses and malware? You can relax. Cookies cannot carry viruses or malware, nor can they transfer such things to other users.

Cookies are a necessary part of the Internet experience and they shouldn’t be feared. For example, deleting your cookies will log you out of sites like MakeUseOf and Facebook. If you like convenience and personalization, then you should learn to embrace cookies.

But what should you worry about?

The worst possible scenario would be the interception or forgery of one of your cookies, which would allow another user to impersonate you on some website. This could result in them eavesdropping on your user data OR hijacking your account credentials. However, don’t be too alarmed. Cookie security mostly depends on the website and your browser; a cookie encryption feature, for example, can help protect you from hackers.

A more prevalent issue is a specific type of cookie called the “tracking cookie.” These cookies aren’t used to better your experience. Instead, they keep track of all of your actions on certain websites. These can be used to build browsing history profiles, which can be used to target specific ads to you. This is where invasion of privacy comes in.

Protecting Your Privacy

Here’s what you need to know about cookie privacy: they cannot know any information that you don’t personally provide. In other words, just because a website has a cookie on you doesn’t mean that they know everyone in your family and which schools you’ve attended–unless you entered that information to the website.

The biggest problem with tracking cookies is that an advertising agency can view your browsing history (since that’s what they use to target ads relevant to your interests). You can prevent them from doing this, of course, by playing with your browser settings and disabling cookies.

If you don’t want to disable ALL cookies (which would keep you from enjoying the legitimate features on legitimate websites), certain browsers let you disable specific cookies from certain domains. Some more advanced browsers let you synchronize with black lists; these are maintained by people or communities to keep out domains with shady cookie practices.

Ultimately, when it comes to cookie privacy, it’s all about trust. Do you trust that website to log every interaction? Read their privacy policy and terms of use–they’re usually linked on the website near the header or footer. If you don’t trust them, you can always wipe your cookies later.

Want to test a website’s cookie integrity? Try “Cookie Checker”. Want to see what sort of cookies are on your computer and what websites are tracking with those cookies? Try Cookie Spy.

By Joel Lee makeuseof.com

How Does File Compression Work?

We’ve all heard of file compression. Anyone who regularly downloads files from the web is familiar with formats like ZIP and RAR, and anyone who edits media files knows that compression is necessary to share images, music and videos on the web without using up all of your bandwidth. File compression is at the core of how the web works, you might argue, because it allows us to share files that would otherwise take too long to transfer. But how does it work?

It’s nothing magical, but it is the result of a lot of hard work by many very smart people. Let’s explore how file compression works by looking over the two main types of compression – lossless and lossy.

Just a warning – I’m going to oversimplify things here in an attempt to make this readable by non-math majors. Check out the linked-to Wikipedia articles for more depth, and Wikipedia’s sources for even more.

Lossless Compression

Lossless compression basically works by removing redundancy. What does that mean? Let’s simplify things. This stack of bricks will represent our data:

As you can see we’ve got two red bricks, five yellow and three blue. The simplest way to represent this is as you see above: the bricks themselves. But it’s not the only way I can represent this. I could also do this:

In the above image you can see the exact same information – two red, five yellow and three blue – but it takes up significantly less space. I’ve represented redundant bricks using numbers, meaning I need only three bricks to represent ten.

This gives you a rough idea how lossless compression is possible. Information that’s redundant is replaced with instructions telling the computer how much identical data repeats. Another simplified example:

fffffffuuuuuuuuuuuu

Can be “compressed” to:

f7u12

This is only one method of lossless compression, of course, but it points to how this is possible. Other math tricks are used, but the main thing to remember about lossless compression is that while space is temporarily saved, it is possible to reconstruct the original file entirely from the compressed one. If you see three bricks with numbers you know exactly how to make the stack. No information is lost, just as the name lossless implies.

Programs like WinZip are based on lossless compression. They remove this redundant information when you compress (or “zip”) the file and restore it when you uncompress (or “unzip”). Nothing is lost.

In the image world, PNG files also use lossless compression. This is why they offer a smaller file size for images with lots of uniform space: that redundant information is represented using instructions.

Of course, this is all an oversimplification, but it gets the basic point across. Read more about lossless compression on Wikipedia, if you’re interested.

Lossy Compression

Of course, there’s only so much you can accomplish using only lossless methods. Happily they’re not the only option: you can also simply remove information. This is called lossy compression, and it’s not as crazy as it sounds; in fact, you probably have many files on your computer made using lossy compression.

An MP3, for example. If you’re like most people your computer stores thousands of them for you, but did you know they don’t contain all of the audio information the original recording did? Some sounds, which humans cannot or can barely hear, are removed as part of the compression. The more you compress a file the more information is removed, which is why an overly compressed file will start to sound muddy.

Lossy compression tends to mostly be used for media files – pictures, sound and video. Using lossy compression for a text file would be problematic, as the resulting information would be garbled. It’s not always necessary for media files to include all the information, however.

Another example of lossy compression is the JPEG image. Generally speaking images seen on the web do not need to be as high-quality as images intended for printing. As such, you can remove a lot of redundant information in a web image, even if doing so would look awful printed.

Of course, repeatedly compressing a file using lossless methods decreases the quality – every time you do it more data is lost. Below is a photo I’ve compressed three times to demonstrate this:

You can see from left to right how the quality decreases. It may not matter, depending on what the image will be used for, and that’s why lossy compression exists.

It’s important to remember that files compressed using lossy methods actually lose data, meaning you cannot recreate the original file from one compressed using lossy methods. It’s obvious when you think about it, but many printing projects have been ruined for lack of understanding this key point.

I’ve really only scratched the surface here, so please: read more about lossy compression on Wikipedia. It’s kind of fascinating.

Conclusion

Compression helped make the web what it is. In the days of dialup compressed images brought photos to our browser, at least not at an acceptable speed. Compressed video makes sites like YouTube possible, and anyone who uses file sharing networks is familiar with ZIP and RAR files.

Do you have anything to add? I’m sure I’ve missed some key points so educate me (and the other readers) in the comments below.

3D TVs: What They Are, How They Work, & What Can They Show In 3D?

If you’re in the market for a new TV, chances are it’s going to be 3D – not because you particularly want one that can do 3D, but simply becuase 3DTVs typically have better displays than their plain HDTV equivalent. Today I’d like to explain about the different types of 3DTV as well as touch on some confusion that surrounds them.

Types Of 3D Display

To misquote someone famous who may have never existed – all 3D displays are not created equally. In fact, there are three basic 3D display types available, whether you’re dealing with TVs, monitors, or gaming handhelds.

Active Shutter

Active shutter 3D displays work by displaying frames sequentially; one frame for the left, then one frame for the right eye, then repeat. Using powered glasses with LCD screens in them that are synced to the same frequency as the TV, the glasses alternative between blocking the vision of each eye. The left eye is shown the frame for the left portion of the scene; then it blacks out, and the right sees the frame for the right portion of the scene.

This sounds annoying, but in reality it happens so quickly – around 60 times a second – that you barely notice. I say “barely”, because some people do notice a slight flashing, and often report headaches after prolonged usage.

You can tell which TVs are “active shutter” because the glasses will require recharging via a USB cable, or have small user-replaceable batteries. They also weigh more, and cost more than other types of glasses – so an additional pair may set you back about $50 or more.

However, active displays are generally considered to be the best quality of 3D due to the fact that each frame is completely blocked from the other eye, leading to less “bleeding” between images (where you can see both frames at the same time in some situations). You’re also getting a higher brightness due to one frame being sent at any one time; passive displays show both the left and right images at all times.

Passive (Polarised)

Passive 3D displays work by displaying both the left and right frames simultaneously. Each frame is run through a different polarising filter – this “aligns” the light waves into one direction only. When those light waves hit your 3D glasses, they come against another set of polarising filters, such that only light destined for the correct eye is allowed to pass through.

The quality of passive 3D is not quite as good; it’s a primitive technique, and simply doesn’t allow for as much depth as active 3D, as well as suffering from generally murky images. Since you’re blocking half of the total brightness given out by TV, you also end up with a darker picture than you would with an active display.

On the plus side, the glasses used for passive TVs are very cheap; it’s likely your TV will actually come with 8 pairs. They also don’t need batteries, operating purely on the power of physics! Cheap and cheerful – great if you have kids and expect glasses to break often or gets KFC grease on them constantly.

Lenticular (Glasses Free)

Lenticular is the technology behind the new breed of 3DTV that doesn’t need glasses, and some existing consumer devices like the viewscreen on 3D cameras and the Nintendo 3DS gaming console. The technology is a little like the optical illusion “hologram” cards you used to get in cereal boxes; as you moved the card around, a different image would be displayed.

With lenticular 3DTVs, light is directed at specific angles such that if you closed one eye and walked around the TV, you would see alternative left and right frames. It’s an interesting technique, but in reality it means there are only a set number of places from which you can view the TV (and don’t even think about doing sillly things like lying down to watch a movie or twisting your head slightly).

With 3DTVs rumored to be launching in early 2013, you should be aware of the issues I’ve mentioned about specific fixed viewing angles. Although many people believe that “glasses free” is the future of 3D, the fact is the quality of 3D displayed on these devices currently is very poor, something that Twentieth Century Fox has also warned about.

2D To 3D Conversion / Emulation

Most 3DTV’s come with a 2D to 3D conversion mode that magically turns a regular 2D broadcast into a 3D one. Avoid these like the plague. Using a series of algorithms, the TV attempts to analyse the picture and distinguish the foreground objects from the background. Then to create the 3D illusion, foreground objects are pushed apart, creating the sense of “closeness”.

Humans are suprsingly good at this; if you close one eye, you still have a fairly good idea of the depth on each object you’re seeing, because you’re able to combine knowledge of what the object is, how big it should be, perhaps how far away it was in the past, etc. Trying to ask a computer to analyse the scene in real time and figure out where each object is – now that’s just difficult. I showed you a similar technique in Photoshop a few months ago, with less than impressive results.

The trouble is that no matter how much analysing you do, the results will always be poor. It’s like trying to reconstruct the sounds of a live orchestral piece from a badly encoded 64kbs mp3 recording of one. It simply can’t be done. So my advice is not to enable 3D mode for everything; just for things that are actually broadcast or recorded in 3D.

So What Can You Play On a 3DTV?

Over The Air & 3D Cable Channels: The BBC has been fairly prolific with 3D broadcasting this year for both Wimbledon Tennis and the Olympics; while Sky has a 3D channel available (you may need to sell a kidney or two to afford the monthly charges though).

3D Blu-ray: Get a 3D comptible Blu-Ray player, or just buy a Playstation.

Playstation 3: Supporting both 3D Blu-Rays and an extensive collection of games, Sony is really leading the way with 3D offerings.

Xbox 360: A very limited selection of games support 3D mode; including Call of Duty Black Op2, launching this November.

PC Games: Grab some third party drivers from TriDef.com and have the world of 3D gaming open up to you. Note; these don’t magically turn your PC in a graphical power machine – if your computer can’t handle regular gaming, then it certainly can’t handle 3D gaming. In fact, you’ll twice as much power since you’re effectively driving 2 displays.

I think that explains the technology behind 3D TV’s and what to watch out for when buying one. I hope you can make an informed decision, and understand a little more about how they work and what content is available. Comments and suggestions welcome – however, please don’t ask “can my laptop / non 3D-TV play 3D movies?” – because it can’t.

By James Bruce makeuseof.com

Related articles

• Own the Full HD 3D Experience
• New 3D Display Lets Phones and Tablets Make Holograms
• 3D TV, Without the Glasses

What Is The Difference Between A Netbook, Notebook, Ultrabook, Laptop, & Palmtop?

In a time not so long ago, the only choice to make between computing devices was between a hulking great desktop, or a laptop … which was still fairly huge. The constant miniaturation of technology and need for manufacturers to differentiate their products has now given us a smorgasboard of sizes; each with their own name. Let me show you the differences.

Order of size

Generally speaking, we can actually give a fairly broad ranking of these names by size, from smallest to largest:

1. Palmtop
2. Netbook
3. Ultrabook
4. Notebook
5. Laptop

It may be more accurate to say this is in order of portability – since you can get a biggerscreensize on a particular ultrabook than you would on a particular notebook; however, the notebook would be thicker and heavier.

With that out of the way, let’s look at some examples of each and their defining characteristics. All of these devices share one characteristic though: they all feature a clamshell design – that is, they had a screen in the lid, and it opens and closes like a clamshell; we won’t be talking about tablets or touchscreen mobile devices here.

Palmtops

The smallest devices that could give you a full computing experience, most palmtops ran a special low powered version of Windows called Windows CE, but there were later models running that could run regular Windows XP. With the advent of smartphones, the palmtop computer was made obselete and you can’t really buy one today (though you could probably track a few down in second hand shops in Japan). These devices had a screensize of around6–7 inches. (Pictured: the HP–760LX)

Netbooks

With a screensize of around 9 –10 inches, netbooks were quite popular before the iPad launched. They represented a truly portable full computing platform, with a tactile keyboard(ie, one you can actually push the buttons on rather than simply touch).

Although impractical for daily use, they run Windows so you can use all the applications you’re used to – as opposed to a tablet or mobile phone, which can’t run regular Windows applications.

Their popularity has declined in recent years, but you can certainly still buy them for around $200 – $500. They are suitable for daily computing tasks, but gaming and intensive applications like Photoshop or video editing are not possible. (Pictured: the Asus EEE-pc)

Ultrabooks

These are the new breed of “ultra-portable notebook” – typically weighing less than 1.5kg, and extremely thin. The word was invented by PC manufacturers as a direct response to the Apple Macbook Air, the first true “ultrabook”. Despite the thin profile of ultrabooks (less than 2cm), screen sizes can often rival “normal” notebooks – anywhere from 11 to 15 inches. Most are equipped with SSD hard drives – these are silent, lighter, and much faster than regular HDDs, giving an “instant on” feel that avoids lengthy boot-up times. Although much faster, SSDs are more expensive than HDDs, so you’ll get less GBs for your money – just128gb wouldn’t be unusual in an ultrabook. Ultrabooks also typically don’t have a DVD-drive, so bear this in mind if you’re shopping for a laptop to play your DVDs on.

Suitable for most computing tasks and lightweight gaming, they will struggle with the higher end 3D games. Ultrabooks can vary in price between around $700 to $1500. (Pictured: the Macbook Air)

Notebooks and Laptops

Historically, a laptop was a little larger, designed to be a replacement for a desktop that could still sit in your lap. Notebooks were simply a little smaller than laptops – something you could carry around anywhere, synonymous with a paper “notebook”. Nowadays however, there is no distinction. Manufacturers will use the terms notebook and laptop interchangeably; and it’s rare to see the term laptop used at all now.

Notebook is a bit of a catch-all. Anything that isn’t any of the above, is a notebook, so attempting to define price ranges is impossible; top of of the line notebooks can go as high as $4000. Screen sizes vary between 12 – 18 inches, though 15″ is the average. You can get notebooks with a powerful graphics card too for 3D gaming, though this isn’t true for all notebooks. Notebooks will usually have a DVD-drive and large hard disks; if they didn’t they would probably be termed ultra-books instead. (Pictured: a top-end Alienware notebook, an incredibly powerful machine)

By James Bruce makeuseof.com

Related articles

• What sets Ultrabooks apart from traditional notebooks?
• Netbooks, Ultrabooks can coexist, expert says
• Advantages and Disadvantages of a Netbook

Are You SURE You Know How to Use Google?

Most of you are probably thinking “you bet!” or “what’s there to KNOW?” right about now. I believe you. The truth is, if you know how to enter a query and hit enter, you know how to use Google. At least in its basic form. And if you search often, you’ve probably also encountered Google’s OneBox results once or twice before.

What are these OneBox results? While you may not have heard the name before, OneBox results have been around for years now, and have been helping you get focused and clearer results for your search queries. Have you ever searched for the local weather and got a small widget on top showing you what the weather is like today? That’s a great example of OneBox results. This is not to be confused with Knowledge Graph results, which appear to the right of the page. Knowledge Graph results were added less than a year ago.

The new and slick Knowledge Graph aside, there are still dozens of useful things you can find out from OneBox results. All you need to know is the right syntax to activate them, and you’re into a whole new world of Google results. This could take you all day to read if I try to mention them all, but here are some you definitely don’t want to miss. Looking for more useful search tips? Check out  Google Search cheat sheet.

Entertainment

When it comes to movies, books, music, etc., Google is full of useful surprises. Want to explore the full discography or filmography of an artist? Look for [artist] movies or [artist] albums. This yields a visual display of all movies/albums, complete with covers, names and release dates. Click on any album/movie to read more about it in Knowledge Graph.

This works just as well with authors: search for [author] books. You can get the roster for any sports team in the same fashion by looking for [sports team] roster.

You can also search for [artist] latest album to quickly find what the latest release was.

Found a movie you want to watch? Search for [name of movie] [zipcode] to find local show times (works in the US, Canada, and most of Europe, might also work in other regions). Can’t decide which movie to watch? movie [zipcode] will find local show times for all movies playing around you.

Want to find when your favorite team is playing next? Searching for the team’s name will yield all upcoming and recent games, complete with scores (if applicable), rival teams, team logos, times and ticket links.

Numbers

In the olden days, people calculated things in their heads, or using pen and paper. Later on, we started using calculators for everything. Today, you don’t even need to launch (or bring) your calculator for most things, just use Google. Google’s calculator can handle anything from simple calculations to more complex ones. All you have to do is search for the equation, and Google will present the result.

Want to continue calculating with your result? Google’s calculator is completely usable, and you can use it to continue your calculations.

You can also use Google to draw graphs, from simple ones to 3D ones. Enter an equation in the search box and see what happens.

But there’s more to numbers than math equations. In day-to-day life, we commonly use numbers as measurements. Google has you covered there too. How many milliliters are there in a cup? How many grams in an ounce? Google shows immediate results for all such queries. You can even play around with the dropdown menus to get further conversions.

The same trick works with currency conversions. Just search for “23 usd in euro” (or anything similar) and get an immediate conversion, along with a full graph of currency-rates history.

Travel

Flying somewhere? Google shows OneBox results for general flight searches as well as flight information for specific flights. Look for [airline] [flight number] to find out where this flight is at the moment, where it’s coming from and when and where it’s landing.

If you search for “flights from [X] to [Y]” you’ll find a list of available flights with current prices. But what if you’ve decided to drive this time? How long is it going to take you?

Try searching for [starting point] to [destination] and see what happens. This trick doesn’t always work, and I only got it to work with US addresses, but you can play around and see what you get.

Already there and looking for things to do? Searching for “things to do in [place]” will yield a visual guide to the most popular local attractions. Clicking on an attraction will show its specific Google search results.

General Knowledge

There’s an endless amount of facts to be found on Google, and you may encounter hidden OneBox results you didn’t know existed just by entering your queries. But in case you’re curious, here are some interesting ones worth trying.

Looking for health information? Google provides instant information on some diseases and medicine. Type in the name to see what you get.

Interested in gaining some general knowledge? Google offers instant results for questions like “how big is Paris?”, “who is the president of Micronesia?”, “how tall is the Empire State building?” and many others.

You can also find such oddities as team mascots and dog-breed characteristics in this way.

Google also helps you in the language department, by providing both instant translations and instant dictionary definitions for English words. This doesn’t work for every word in the English language, naturally, but it usually works for words you might need a definition for.

To get instant translations, search for “translate [word] to [language]”. This works in all languages supported by Google Translate.

Are You Sure NOW?

While I’m sure you could search Google before, these neat tricks sure make it easier and much more fun. The most exciting part about it, is that Google keeps adding more and more of these. When writing these post, I kept searching for random terms and queries to see if I can find some cool OneBox results.

Have you found a really useful one I missed? Is there one you use all the time that I didn’t mention? Share your favorite search tips in the comments.

By Yaara Lancet makeuseof.com

Electronique générale

You’ll find in the folder:

-2012-2013

-Corrigés

-Devoirs

-Examen-Corrigé

-TD

-TD _2012

click here or click on the blue