Online advertising is a form of promotion that uses the Internet and World Wide Web for the expressed purpose of delivering marketing messages to attract customers. Examples of online advertising include contextual ads on search engine results pages,banner ads,Rich Media Ads, Social network advertising,interstitial ads, online classified advertising, advertising networks and e-mail marketing, including e-mail spam.
The three most common ways in which online advertising is purchased are CPM,CPC and CPA.
Privacy
The use of online advertising has implications on the privacy and anonymity of users. If an advertising company has placed banners in two Web sites. Hosting the banner images on its servers and using third-party cookies, the advertising company is able to track the browsing of users across these two sites.
Third-party cookies can be blocked by most browsers to increase privacy and reduce tracking by advertising and tracking companies without negatively affecting the user's Web experience. Many advertising operators have an opt-out option to behavioural advertising, with a generic cookie in the browser stopping behavioural advertising.
Tuesday, November 23, 2010
Sunday, November 7, 2010
3g Technology
3G Technology
Here is a simple introduction to some aspects of 3G radio transmission technologies (RTTs).Simplex vs. Duplex
When people use walkie-talkie radios to communicate, only one person can talk at a time (the person doing the talking has to press a button). This is because walkie-talkie radios only use one communication frequency - a form of communication known as simplex:
Simplex: Using a walkie-talkie you have to push a button to talk one-way.
Of course, this is not how mobile phones work. Mobile phones allow simultaneous two-way transfer of data - a situation known as duplex (if more than two data streams can be transmitted, it is called multiplex):
Duplex: Allows simultaneous two-way data transfers.
The communication channel from the base station to the mobile device is called the downlink, and the communication from the mobile device back to the base station is called the uplink. How can duplex communication be achieved? Well, there are two possible methods which we will now consider: TDD and FDD.
TDD vs. FDD
Wireless duplexing has been traditionally implemented by dedicating two separate frequency bands: one band for the uplink and one band for the downlink (this arrangement of frequency bands is called paired spectrum). This technique is called Frequency Division Duplex, or FDD. The two bands are separated by a "guard band" which provides isolation of the two signals:
FDD: Uses paired spectrum - one frequency band for the uplink, one frequency band for the downlink.
Duplex communications can also be achieved in time rather than by frequency. In this approach, the uplink and the downlink operate on the same frequency, but they are switched very rapidly: one moment the channel is sending the uplink signal, the next moment the channel is sending the downlink signal. Because this switching is performed very rapidly, it does appear that one channel is acting as both an uplink and a downlink at the same time. This is called Time Division Duplex, or TDD. TDD requires a guard time instead of a guard band between transmit and receive streams.
Symmetric Transmission vs. Asymmetric Transmission
Data transmission is symmetric if the data in the downlink and the data in the uplink is transmitted at the same data rate. This will probably be the case for voice transmission - the same amount of data is sent both ways. However, for internet connections or broadcast data (e.g., streaming video), it is likely that more data will be sent from the server to the mobile device (the downlink).
FDD transmission is not so well suited for asymmetric applications as it uses equal frequency bands for the uplink and the downlink (a waste of valuable spectrum). On the other hand, TDD does not have this fixed structure, and its flexible bandwidth allocation is well-suited to asymmetric applications, e.g., the internet. For example, TDD can be configured to provide 384kbps for the downlink (the direction of the major data transfer), and 64kbps for the uplink (where the traffic largely comprises requests for information and acknowledgements).
Macro Cells, Micro Cells, and Pico Cells
The 3G network might be divided up in hierarchical fashion:
- Macro cell - the area of largest coverage, e.g., an entire city.
- Micro cell - the area of intermediate coverage, e.g., a city centre.
- Pico cell - the area of smallest coverage, e.g., a "hot spot" in a hotel or airport.
Why is there this sub-division of regions? It is because smaller regions (shorter ranges) allow higher user density and faster transmission rates. This is why they are called "hot spots".
TDD mode does not allow long range transmission (the delays incurred would cause interference between the uplink and the downlink). For this reason, TDD mode can only be used in environments where the propagation delay is small (pico cells). As was explained in the previous section on symmetric transmission vs. asymmetric transmission, TDD mode is highly efficient for transmission of internet data in pico cells.
TDMA vs. CDMA
We have considered how a mobile phone can send and receive calls at the same time (via an uplink and a downlink). Now we will examine how many users can be multiplexed into the same channel (i.e., share the channel) without getting interference from other users, a capability called multiple access. For 3G technology, there are basically two competing technologies to achieve multiple access: TDMA and CDMA.
TDMA is Time Division Multiple Access. It works by dividing a single radio frequency into many small time slots. Each caller is assigned a specific time slot for transmission. Again, because of the rapid switching, each caller has the impression of having exclusive use of the channel.
CDMA is Code Division Multiple Access. CDMA works by giving each user a unique code. The signals from all the users can then be spread over a wide frequency band. The transmitting frequency for any one user is not fixed but is allowed to vary within the limits of the band. The receiver has knowledge of the sender's unique code, and is therefore able to extract the correct signal no matter what the frequency.
This technique of spreading a signal over a wide frequency band is known as spreadspectrum. The advantage of spread spectrum is that it is resistant to interference - if a source of interference blocks one frequency, the signal can still get through on another frequency. Spread spectrum signals are therefore difficult to jam, and it is not surprising that this technology was developed for military uses.
Finally, let's consider another robust technology originally developed by the military which is finding application with 3G: packet switching.
Circuit Switching vs. Packet Switching
Traditional connections for voice communications require a physical path connecting the users at the two ends of the line, and that path stays open until the conversation ends. This method of connecting a transmitter and receiver by giving them exclusive access to a direct connection is called circuit switching.
Most modern networking technology is radically different from this traditional model because it uses packet data. Packet data is information which is:
- chopped into pieces (packets),
- given a destination address,
- mixed with other data from other sources,
- transmitted over a line with all the other data,
- reconstituted at the other end.
A data packet.
The major part of a packet's contents is reserved for the data to be transmitted. This part is called the payload. In general, the data to be transmitted is arbitrarily chopped-up into payloads of the same size. At the start of the packet is a smaller area called a header. The header is vital because the header contains the address of the packet's intended recipient. This means that packets from many different phone users can be mixed into the same transmission channel, and correctly sorted at the other end. There is no longer a need for a constant, exclusive, direct channel between the sender and the receiver.
Packet data is added to the channel only when there is something to send, and the user is only charged for the amount of data sent. For example, when reading a small article, the user will only pay for what's been sent or received. However, both the sender and the receiver get the impression of a communications channel which is "always on".
On the downside, packets can only be added to the channel where there is an empty slot in the channel, leading to the fact that a guaranteed speed cannot be given. The resultant delays pose a problem for voice transmission over packet networks, and is the reason why internet pages can be slow to load.
Latest Mobile Phones
The Minister of State for Communications, Sachin Pilot has recently stated that Bharat Sanchar Nigam Limited will expand its 3G services in 120 more cities by the end of this year. Presently BSNL has its 3G operations in 640 cities across the country.
The MD and Chairman of BSNL, Gopal Das also stated that it is expected by BSNL that by March 2011, it will increase its subscriber base in the 3G segment by 2.5 million. The Indian government provided licence of 3G to MTNL and BSNL much earlier than the private telecom operator.
Lenovo P500 Candybar Handset
Lenovo P500 is the latest mobile phone from the company which comes packed with variety of features for your communication. This latest handset comes with 2.8 inches of TFT LCD display that offers WQVGA resolution count of 240 X 400 pixels.
To capture all your special moments in form of impressive quality images, the phone comes with 3 MP camera and moreover a front camera is also provided for video calling. The media player in the phone provides unlimited entertainment and its Bluetooth option offer connectivity with other devices.
Lenovo P500 uses the ThinkPad Roll solution and its 1200 mAh battery provided talktime of around 4 hours and standby time of around 7 days. Others features of the phone include expandable memory up to 8GB, GSM and HSDPA network connectivity, alphanumeric keypad and others.
Lenovo P500 physically measures 118.8 X 49.5 X 11.5mm with weight of 120 gm. The availability and price of the phone is not yet available.
To capture all your special moments in form of impressive quality images, the phone comes with 3 MP camera and moreover a front camera is also provided for video calling. The media player in the phone provides unlimited entertainment and its Bluetooth option offer connectivity with other devices.
Lenovo P500 uses the ThinkPad Roll solution and its 1200 mAh battery provided talktime of around 4 hours and standby time of around 7 days. Others features of the phone include expandable memory up to 8GB, GSM and HSDPA network connectivity, alphanumeric keypad and others.
Lenovo P500 physically measures 118.8 X 49.5 X 11.5mm with weight of 120 gm. The availability and price of the phone is not yet available.
Dell XCD28 3G Android Handset
November 6th, 2010 No comments
Dell XCD28 is the latest Android Mobile Phone that runs on 2.1 version of the OS. This mobile phone provides support to quad band GSM and 3G connectivity. Physically Dell XCD28 measures 102 X 55 X 14.5 mm in size with weight of 100g and boast 2.8 inches of resistive touchscreen offering resolution count of 320 X 240 pixels.
For the music lovers there is good quality music player in the phone along with speakers. The 3.2 MP camera of the phone comes with AF option so that bright and clear images can be captured even in low light conditions. Video recording facility is also provided by the camera of the phone.
Other list of features that comes packed in Dell XCD28 include GPRS, EDGE, Wireless LAN WiFi, Bluetooth v2.1 with EDR, microUSB, expandable memory up to 16GB, access to social networking sites and others.
Dell XCD28 is available in the market with a price tag of Rs.10,600.
Lenovo P500 Price
November 6th, 2010 No comments
Lenovo Mobiles has Launched a new mobile named P500. Its Feature 3 MP camera and moreover a front camera is also provided for video calling.
Lenovo P500 Price, Features
- 2.8 inches WQVGA Display
- GSM and UMTS/HSDPA networks
- Hardware alphanumeric keypad
- Micro SD Card 8 GB
- 3 Mp Camera
- Front Video Calling Camera
- Music Player
- Video Recording & Play
- Bluetooth
- Weight 120 gr
- Battery Stand by 7 days
Lenovo P500 phone from the company which comes packed with variety of features for your communication. Lenovo P500 Price in India Rs.(N/A)
Nokia E55 Photos, Pics
November 6th, 2010 No comments
The Nokia E55 Running with Symbian OS, S60 rel. 3.2 and ARM 11 600 MHz processor. It s Other Features 3.2 Mp Camera with Auto focus and LED Flash, Document Viewer, Digital Compressor, A-GPS Support with Nokia Maps.
The Nokia E55 comes with Black Aluminium, White Aluminium, Red Colors for stylish looking.
Nokia E75 Photos, Pics
November 6th, 2010 No comments
Nokia E75 is 3G mobile comes with 2.4 inches QWERTY keypad and Accelerometer sensor for auto-rotate. It Supports Micro SD Card up to 16 GB & 4 GB Included, GPRS & EDGE for Internet Access, 3G HSDPA, 3.6 Mbps.
The Nokia E75 Running with Symbian OS, S60 rel. 3.2 and ARM 11 369 MHz processor. It s Other Features WLAN & Bluetooth Connectivity, Document Viewer & Editor, 3.2 Mp camera with Auto focus & Led Flash.
The Nokia E75 comes in Silver black, Red and Copper yellow Colors.
Nokia N86 Photos, Pics
November 6th, 2010 No comments
Nokia N86 is a 3G Supported Slider Mobile comes with 2.4 inches AMOLED Display and Scratch-resistant surface. Its a Music Central Mobile with 3.5 mm Audio jack and Dedicated Music/Gallery keys.
The Nokia N86 Running with Symbian OS v9.3, S60 rel. 3.2 and ARM 11 434 MHz processor. It s Other Features 8 Mp Camera with Carl Zeiss lens, autofocus, dual LED flash, WLAN, Bluetooth and much more.
The Nokia N86 comes in Indigo Black and White Colors for Stylish and Rich Look.
LG C320 InTouch Lady Price
November 6th, 2010 No comments
LG C320 InTouch Lady
LG C320 In Touch Lady mobile comes from LG Mobiles. It comes in Slider and QWERTY keypad in Low Price in India.
LG C320 InTouch Lady Price, Features
- high Resolution Display
- QWERTY keypad
- 2 Mp Camera
- Video Recording & Play
- 3G- HSDPA
- Bluetooth with v2.1
- Music Player
- Micro SD Card Slot
- Face book and Twitter
- Extra Long battery Life
Samsung Messager III r570 Price
November 6th, 2010 No comments
Samsung Mobiles has Launched a new Mobile named Messager III r570. It comes with QWERTY keypad and great list of Features in Affidavit Price.
Samsung Messager III r570 Price, Features
- 2.4 inches QVGA Display
- Sliding QWERTY keypad
- Micro SD Card up to 16GB
- Bluetooth
- 3.5 mm Audio jack
- 1.3 Mp Camera
- Video Recording & Play
- Music Player
- Social Networking Accessories
- Widget Support
- 1140 mAh Battery
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Samsung Solstice II a817 Price
November 6th, 2010 No comments
Samsung Mobiles has Launched a new Mobile Named Solstice II a817. It comes Large Touchscreen Display with high resolution and great Features.
Samsung Solstice II a817 Price, Features
- 3 inches Touchscreen Display
- 3G- HSDPA
- GPS navigation with AT&T Navigator
- Internal 256 Mb of Memory
- Micro SD Card up to 16 GB
- Bluetooth
- 2 Mp Camera
- Mobi TV & Mobi VJ
- Subscription-based voice command application
- Vlingo
- Samsung Touch Wiz UI
- Battery Stand by 10.4 days
Samsung Solstice II a817 is a Touchscreen Display Mobile with Handwriting Recognition . Samsung Solstice II a817 Price in India Rs.(Not Announced)
Thursday, November 4, 2010
GEDAYC Revolution wind turbine concept works at almost all wind speeds
Wind is no doubt one of the most reliable sources of renewable energy. Conventional wind turbine designs, however, fail to get the most out of it at low wind speeds, and hence, they require some design-related modifications. Spanish industrial designer David Sarria Jiménez proposes an innovative wind turbine design that promises to be five times cheaper, faster, easier to install and fabricate than current models. The much smaller turbines, dubbed as GEDAYC Revolution, can utilize weak to very strong winds to generate energy.
The highly efficient wind turbine could rotate its wings at 6m/s wind speed with extreme ease. Flaunting blades and kites, the concept turbine is quite capable of generating 50% more power than the traditional propeller-based models.
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