Tuesday, June 9, 2009

Wi-Fi technology

Wi-Fi technology is a wireless technology that uses radio waves for providing internet access or establishes connection between two or more devices for the purpose of data sharing. The Wi-Fi technology was established in 1997 and has gained huge popularity since then. Wi-Fi is supported by most of the computers, laptops, smart phones, IPods, PSP and various other peripherals.

Wi-Fi is a long distance transportable technology which can be used by millions of people all over the world for individual and business purposes. Wi-Fi technology uses single carrier direct-sequence spread spectrum radio technology as well as multiple carrier OFDM technology to establish connection between two or more networks. The wireless technology offers both advantages and disadvantages as compared to a wireless network. Advantages include more mobility whereas disadvantages include radio interference due to weather and other wireless devices.

How does Wi-Fi Technology work?

A Wi-Fi connection begins with a wireless computer adapter that translates data into a radio signal and transmits it using an antenna. Thereafter, a wireless router receives the signal and decodes it- and sends the information to the internet using a physical, wired Ethernet connection. In reality the router is connected to a high-speed modem with the help of the Ethernet cable. After the wireless router gets connected, you will be able to receive a wireless signal on a given device- be it a computer, laptop, smart phone or any other device.

The Wi-Fi radios have a remarkable difference from the other radios- as they transmit frequencies of 2.4 GHz or 5 GHz which is considerably higher than the frequencies of cell phones, walkie-talkies and televisions. The advantage of using higher frequency is that the signal can carry more data. The Wi-Fi radios typically use 802.11 networking standards, which come in several flavors like 802.11a, 802.11b, 802.11g, and 802.11n. Wi-Fi radios can transmit on any of these frequencies or may "frequency hop" between the different bands. Frequency hopping actually helps in reducing interference and lets multiple devices use the same wireless connection simultaneously.

However, in spite of the advantages, this technology has some limitations as well. It is because the spectrum assignments or operational limitations are not consistent throughout the world. Many places in Europe allow for only one additional channel for the 2.4 GHz band. (1-13 vs. 1-11); Japan has one more on top of that (1-14). This means that the Wi-Fi connection cannot operate consistently in these countries. Moreover, the Wi-Fi systems have only a limited range and the Wi-Fi performance decreases significantly as the distance increases.

Wi-Fi technology has certainly improved our way of communicating and establishing connections but a lot still remains to be done!

Wednesday, May 20, 2009

Video Teleconferencing Technology

Video Teleconferencing technology is a new technology that has been invented to give a cutting edge to your business! The Video teleconferencing technology allows two or more persons, present at different locations to interact with each other for business purposes (with the help of audio and video transmissions). The video conferencing technology is gaining huge popularity day by day because it can be used for a variety of purpose such as teaching lessons, conducting meeting and seminars!

The teleconferencing technology allows data to come in your system through phone lines and internet connections. The video teleconference system includes the following components: video input, video output, audio input, audio output and data transfer. The core technology that a video teleconference system uses is the digital compression of the audio and video streams in real time. It has been found that compression rates of up to 1:500 can be achieved in this system.

The resulting digital stream of 1s and 0s is further subdivided into labeled packets, which are thereby transmitted through a digital network of some or other kind. In order to receive the compressed bits of information, you need to have a system in place which can handle the bandwidth required for the conference. It is quite easy to set up a system for receiving the information and most of the people generally use their computers since much of the information required to be saved or shared during the conference can be stored here.

In order to send some image or data from your system, you need to have a web cam or video camera. Simple web cams are quite cheap and easy to install but you may get an expensive video recorder installed if you want very good quality video conferencing. Simple web cams do not have the bandwidth to transfer information at a high quality which you may be able get with more costly equipment. However, expensive video cams are not required everywhere, so you can get away with them.

Video teleconferencing is a very effective technology and is helping lots of companies to stay abreast with the latest knowledge and projects. The use of video teleconferencing technology is helping the smaller companies to stay competitive with the larger ones and also helps them to lower their overhead and keep their costs down, which can even benefit the consumer by keeping prices from rising!

So, you can see that video teleconferencing technology is very profitable to the companies and its' popularity is increasing day by day. I hope that more inventions like this continue to happen and ease our lives!

Wednesday, May 13, 2009

Hydrogen Fuel Cell

The hydrogen fuel cell works on the basis of electrolysis process. It generates electricity with fuel on the anode side and the oxidant on the cathode side and they react in the presence of electrolyte. The reactants which are the input flows into the cells and the reactant products flow out of it while the electrolyte remains inside it. The hydrogen fuel cell is just like the water fuel cell which was a failure. However the hydrogen fuel cell is a success. The fuel cells can run continuously if the input is maintained properly.

Hence the hydrogen fuel cell is just like the petrol engine and I must tell you that it works fine as well. However the fuel cells are different from the electrolytic cells as they consume the reactant from the external source, which requires a thermodynamically open system. Many combinations of the fuel and the oxidants are possible. For example the hydrogen cell uses the hydrogen as the fuel and oxygen as the oxidant. The other combinations are hydrocarbon and alcohol as well as chlorine and chlorine dioxide.

The fuel cell works with the help of electrolysis. Up till now you must have understood the use of reactant as well as oxidants. However you will have to understand one more thing and that is catalysis. The fuel cell works with the help of catalysis which helps in separating the electrons and protons. Now you must know that the electric current flows in the direction opposite to the flow of the electron. I must say that the electron flow is maintained with the help of catalysis which separates the electron and proton and hence the electrons start moving in one direction and hence the electricity is generated.

A typical hydrogen fuel cell produces about 0.6 to 0.7 volts of voltage. However this cell does not obey the ohms law. You must know that according to Ohms law the voltage is directly proportional to the current. However this is not the case with the hydrogen fuel cell. In case of the hydrogen fuel cell the voltage is found to go o decreasing as the current starts increasing.

The reason behind the decrease in the voltage is because of the facts that are as follows:
  1. Activation loss
  2. Ohmic loss: (due to the resistance of the cell components and interconnect.)
  3. Mass transport loss (due to the depletion of the reactants at the catalyst site.)
Hence it is a general observation that the hydrogen fuel cell do not obeys Ohms law. In fact all the electrolytic cells do not obey the ohms law and hence hydrogen fuel cell which is also a kind of electrolytic cell does not obey the ohms law.

Tuesday, April 7, 2009

Universal Turing Machine

Every Turing machine reads a set of symbols which you can call input or also fixed partial computable function which is accepted from the input strings over its alphabet. In this sense it behaves like a computer with a fixed program. However, it is really possible to encode the action table of any Turing machine in a string. Hence a Turing machine can be constructed that expects on its tape a string describing an action table followed by a string describing the input tape, and then it can compute the required result. I must tell you that the Turing described such universal machine in great detail when he wrote a paper in the year 1936.

In 1947, Turing said that "It can be shown that a single special machine of that type can be made to do the work of all. It could in fact be made to work as a model of any other machine. The special machine may be called the universal machine".

I must tell you that there are four kinds of grammar respectively type 0 grammars, type 1 grammar, type 2 grammars and the type 3 grammar. The Turing machine takes the type 0 grammar as the input. The others are accepted by the other machines like push down automata.

If you want to develop the universal Turing machine then you will have to develop the table at first. The table clearly mentions the initial and the final state with correspondence to each input. In this way you will be able to develop a table. You must know that the Turing machine consist of seven tuples. You will have to define the transition state function.

Turing machine is really an attempt to make the machine which will provide the artificial intelligence.
As you will develop the encoding of action tables as strings it becomes possible in principle for Turing machines to answer questions about the behavior of other Turing machines. However I must add that most of such questions are really not decidable. This really gives us one clue and that is that the function in question cannot be calculated mechanically. You can take as an example the halting problem in which you will have to decide whether any Turing machine will halt at the input of any input or on all inputs. This was generally shown to be not decidable when the paper was presented in the year 1936 original paper. You can also check for the rice theorem which shows that any non-trivial question about the behavior or output of a Turing machine is not decidable.

I really feel that the Turing machine was really a very good attempt by one of the all time great scientist and that is the Turing.

Tuesday, March 31, 2009

What are the advantages of Thermoformed Packaging

Thermoformed packaging reduce the per unit packaging cost. Besides this, the packaging offers several other benefits. Before going into the detail of all the advantages, let's find out what is thermoformed packaging.

This is a type of retail packaging. The clamshell packets which carry and hold toys, gifts, electronic goods, cosmetics and food items are nothing but the thermoformed packages. These are forms by melting the plastics. The melted plastic is then treated under vacuum and pressure over the customized moulds. This molding gives the particular shape to the plastic. It is then trimmed and cut to give it the desired shape. It is then assembled to pack the product. The custom based moulds are formed according to the product which is to be packed.

The thermoformed plastic thus gives the feature of both protection and display. The hard plastic case protects the product from dirt and injury. The transparent nature display the product features inside the clamshell. You can find such clamshell in the boxes containing the toys. The cell phones and accessories are also available in such casing.

Food items are also packed in such packages. This is because thermoformed packages don't affect the food properties, it keep the food tightly packed inside which prevent it from getting contaminated.

The other advantages of thermoformed plastic are:
  1. They are light in weight and durable.
  2. They reduce per unit packaging cost of the product. This help the company to cut down on the packaging cost of the product and thus increase profits.
  3. The thermoformed plastic is sustainable. It can be recycled and thus this reduces the garbage which is dumped by the companies in the environment. Thus the thermoforming technology is environment friendly.
  4. The plastic used for packaging is stiffer than the average plastic. This gives the products a high quality packaging.
  5. The stiff nature of the material has led the manufacturers to down grade to smaller containers.
  6. It acts as a better marketing tool for the manufacturers. The product features are displayed and thus the buyer can see what actually lies inside the packet.
  7. The transportation and inbound costs are reduced as the packaging does not add to the total weight of the product.
The thermoformed plastic is also widely used in the packaging of the medical items and surgical instruments. This is because the medical items remain in the sterilized form inside the clamshell packs.

The thermoformed packaging has taken the industries on waves. You can find almost all the items in the departmental store in such packs. The wide application and use of the plastic in itself indicate its advantages.

Sony Ericsson Xperia X1 Smart Phone

Everyone loves to buy a superb mobile phone which suits his personality. We all love to have all the latest features in it in order to be best and productive in everything we do. The brand mobile makers are providing everything in their phones and nowadays it is not difficult to get all the features in our handsets. But the main thing to get the best features counts a lot. And if we are talking about having the best features and price does not matter us then we should not miss Sony Ericsson's new launch Xperia X1 Smart Phone.

It is completely equipped with the advanced features which make it a unique phone. It is the first phone to operate on Windows Mobile Operating System.

Its features will really make you amazed.
  1. It is the fantastic arc-sliding phone with amazing QWERTY soft and easy typing keyboard to input the data fast and easily. It comes with efficient user interface which will never let you down in front of your friends when you boast it off. It comes in a shining metallic body with 3 inch wide VGA screen and high resolution TFT touchscreen.
  2. It is a complete fun and entertainment and an important accessory wherever you go. It has a sleek and compact body. It can store limitless calls and contact entries. Even it has the perfect battery backup.
  3. It has Bluetooth and GPRS facility to access the Internet with high speed and data communication and sharing of files with instant emailing. Apart from that you will also find Wi-Fi features and 3G capabilities. It is because of HSDPA to perfectly download and upload files in fast speed. It comes with the Microsoft's softwares such as PowerPoint, Excel, Word and Outlook.
  4. It has a unique feature of UI- rotation which means that the screen will automatically change its orientation if the handset is tilted.
  5. It has a secondary video calling camera also and supports MP3/AAC/MPEG4 player and even PLUS handwriting recognition aptitude.
  6. It has an expensive tag but all these features cannot be missed even if we have to compensate for the money. It has an internal memory of 400 MB and even is provided with micro SD expandable slots and comes with FM radio with the RDS technology.
  7. It even has the GPS navigation facility to guide us on the way while traveling.
  8. It has a 3.2 megapixel camera with built-in flash and auto focus with perfect resolution to capture the fantastic moments.
So why not you all go and take that wonderful and smart mobile handset into your hands and feel the difference! Though it is costly but money is not everything if you need to buy that perfection and live your life full of fun and entertainment.

Tuesday, March 24, 2009

International Calling Cards

International Calling Cards are the most important means of communicating with your near and dear ones who are sitting in the far off corner of the world. Since mobile phones are the best way to bring the big world in our hands by being the main source of communication. So with the help of international calling cards we can do the long distance calls easily and efficiently.

Earlier it used to take lots of time and money to do the international calls but with the invention of International Calling cards we have saved money and time with clear and proper communication facility.

What actually we have to do is register them by entering the pin number in the toll free number or better do it by calling the pre-registered number given in the card. The billing of these phones is also very easy as you all can pay them online, or by credit cards or cash. You even get number of prepaid International Calling cards to make a call to international countries. With the help of prepaid cards you can call only for the limited amount of time. If the time reaches its limit, the phone hangs up. But you can also increase the time limit by the numerous facilities available such as of paying extra even after the time is used up.

There are 3 types of calling cards available: -
  1. International cards are the ones to make international calls only.
  2. Overseas cards are those which are used to make overseas calls. In overseas cards, the country where the call is received and the country where the call is made should be the same country only.
  3. The Long-distance calling cards support the facility of accessing the all local, international and even overseas calls without any hindrance.
Thus the International calling cards are affordable and highly available in discount schemes offered by the various companies who are trying to bring their best in the market and attract the customers.
But there are various points to be remembered while buying International calling cards as it may sometimes prove uneasy for you.
  • The consumers should check all the details before buying the cards as few companies give the cards which have a lower quality even they charge very few cents.
  • Sometimes you also happen to bear the noise disturbance which might lead to uninteresting and annoying calls.
  • It is always recommended to first try out the trial cards and then buy them in order to avoid risk.
  • Apart from that hidden fee is also becoming the big issue while making international calls as many companies offer cards of lower rates but charge immensely. So it is recommended to ask for the billing system if you need to stay safe in the future.
Thus following few tips in buying the International Calling Cards, we can save lots of money and hence can be free to talk to our relatives and friends in the distant locations.