Big-O Notation

Often times, order is abbreviated with a capital O: for instance, O(n^2). This notation, known as big-O notation, is a typical way of describing algorithmic efficiency; note that big-O notation typically does not call for inclusion of constants. Also, if you are determining the order of an algorithm and the order turns out to be the sum of several terms, you will typically express the efficiency as only the term with the highest order. For instance, if you have an algorithm with efficiency n^2 + n, then it is an algorithm of order O(n^2).

SOFTWARE

new software's will be posted soon

Hands-on: Belkin N750 DB router extends your Wi-Fi's reach

I tend to resist interim technology tweaks. For example, I'm still using a Linksys WRT600N wireless router from the dawn of the 802.11n age. (Can it be three years already?) There are a few hard-to-reach spots in the house, but it's been running 24/7 and it still works.
However, I've recently added a Samsung Galaxy Tab tablet to my array of Net-connected devices. Usually used in a room on the south side of the house, it routinely requires 3G to access the Internet because my Wi-Fi simply doesn't reach that far. Likewise, a computer in another room needs a 5GHz access point to connect reliably with the Linksys router. It's time to upgrade.

The Belkin N750 DB router

So I was interested when Belkin sent me a note about its new N750 DB wireless dual-band (2.4GHz and 5GHz) N+ router.
According to Belkin, the router ($130 direct, about $99 retail) promises improved coverage through its upgraded antenna system. Another thing that caught my attention: Belkin's claim that the N750 uses "MultiBeam" technology to provide greater throughput at greater distances. It's obviously time for me to enter the modern age of wireless routers.

Make mine MultiBeam

MultiBeam is a refinement of the MIMO technology that's been around since 802.11n was introduced. MIMO (Multiple Input Multiple Output) specifies multiple antennas for a given router (the N750 has five) so multiple signals can be sent and received simultaneously.
A MIMO system collects incoming signals and compares them to see which, if any, of the data streams are fractured because of collisions with objects blocking their path (duct work, metal lathe, appliances, etc.). MIMO merges those signals, using the good parts from each, to assemble a complete data stream -- assuming that the same fragments in each stream won't be mangled by obstructions. It works quite well and typically prevents retries that would slow things down.
According to a Belkin press release, traditional MIMO routers tend to provide "a donut-shaped coverage pattern -- flat and wide." The new Belkin routers, on the other hand, use their internal MultiBeam antennas to "provide improved coverage in all directions -- more of an apple shape." In other words, the new antennas can cover more space, including multistory homes.
Belkin uses a technology described as "implicit beam forming," which tends to focus the signal toward wireless network devices rather than in an omnidirectional pattern that scatters the signal in all directions. In addition, the N750 (as well as its single-band sibling, the N450) transmits data on three streams simultaneously rather than the two streams that are typical for wireless routers. Belkin claims it offers 50% better throughput, but I've yet to see that type of improvement in any product.

Installation

The N750 doesn't connect to the Internet until after you've run Belkin's software on your Windows (XP or later) or Mac (OS X 10.5 or later) computer.

Visual tour: 10 Google+ tips for beginners, Check out these 10 tips to get you started on Google's new social network.

You just got your hands on a Google+ invite -- but what next? Check out these 10 tips to get you started on Google's new social network.

Mute annoying posts

A post you commented on could quickly become popular and suddenly you find responses to it are spiraling out of control. Fear not, Google+ has a "Mute" function. To stop receiving updates from a post and remove it from your stream, click the arrow at the top of the post, then select "Mute this post." To unmute it, follow the same steps and select "Undo mute."

Keyboard shortcuts

Google+ has designed a number of keyboard shortcuts that let you quickly maneuver through your Google+ stream, as well as format your posts using bold, italic and strikethrough fonts.

How to claim a vanity URL

Unlike Facebook, Google+ does not yet offer vanity URLs, or a shorter URL that you can use to point others to your profile. Enter gplus.to: a service that shortens your Google+ URL into something more simple. Visit the site, choose a shorter username then copy and paste the string of numbers identifying your Google+ page. This will create your vanity URL: gplus.to/yourusername.

Double-check with whom you're sharing

Sometimes it's easy to forget who you've put into which Circles. If you ever have doubts when posting an update or sharing a link on Google+, click on the "Limited" link at the top. You'll see photo icons for each of the people who will be able to view and share your post with their connections.

Tag someone in a post

Facebook uses the "@" symbol followed by someone's name to tag a person in a stats update. To tag a person in an update on Google+, type the "+" symbol, followed by their username. As you type, Google+ will autofill possible options.

Share to Google+ from Gmail

When you're logged into your Gmail account, you'll notice a gray bar between your username and the Settings gear icon that says "Share..." This lets you post to your Google+ account without leaving Gmail. Click on the Share button and the same status toolbar from the Google+ interface will pop out, letting you post a picture, video, link or update.

Disable Google+ email notifications

Once you get started with Google+ and others start to add you to their circles, your email inbox will flood with notifications. To turn off select email notifications, visit your Google+ settings page, found by selecting the gear icon in the top right of your Google+ page, then choosing "Google+ settings."

Drag/drop from your computer desktop

There are two ways you can add photos, videos and links to an update in Google+. First, you can click the camera, video or paperclip icons, then search your desktop and folders, and upload it. Or, an easier method: Simply drag and drop the picture, video or link from your desktop directly into the share box.

Manage how others see your Circles

Directly under your Google+ profile picture is information about the people you have in your circles and the circles you are included in. Much like everything else on your profile page, this, too, you can edit. From your Google+ profile page, click the "Edit profile" button, then hover over your Circles information. To edit it, click the gray globe icon. From here, you can choose whether or not you want others to see who you have in your Circles and who has put you in their's.

Disable Google+

If Google+ just isn't for you and you want to leave the service, here's how to do it. Click your full name or email address in the Google+ bar, then click "Account settings" and choose "Account overview." From here, click "Delete profile and remove associated features." This will delete your profile and remove your Google+ posts, circles and other content. You will still be able to access Gmail and most other Google services.