Wednesday, September 30, 2009

Razak Sat Satellite

Malaysia shipped their new RazakSAT satellite from the Royal Malaysian Air Force Subang airfield last Saturday to Kwajalein Island in the Republic of Marshall Islands, where the satellite will be launched on April 21st.

Malaysian RazakSAT satellite The images from RazakSAT, Malaysia’s first home-grown remote sensing satellite, will be available for purchase from the Malaysian Remote Sensing Agency later this year. RazakSAT is named after the second Prime Minister of Malaysia, Tun Abdul Razak, and is a mini class satellite weighing in at 180 kg and will be the first remote sensing satellite in the world to orbit the equator. Science, Technology and Innovation Minister Datuk Dr. Maximus Ongkili said the equatorial orbiting satellite would enable observations of the earth’s surface to be made more often as compared to a polar orbiting satellite. RazakSAT will be able to revisit the same location four to six times a day and has a 2.5m resolution and was built by Malaysian scientists and engineers. Two other small satellites, CubeSAT and InnoSAT, weighing less than 10kg each, were also attached to the body of Razak­SAT.

CubeSAT was developed by Astronautic Technology (M) Sdn Bhd while InnoSAT was developed by Universiti Sains Malaysia, Universiti Teknologi Malaysia and Universiti Malaysia Perlis and they will be used to take images for R&D purposes. Malaysian Remote Sensing Agency director general Darus Ahmad said a committee comprising government agencies such as the military and police would vet requests for “sensitive” images. With RazakSAT, Malaysia now has its own satellite to monitor security in the country, natural resources, and maritime activity. Before RazakSAT, Malaysia launched TiungSAT-1, which was more experimental in nature and had an 80m resolution, but the satellite ceased operations three years after it was launched in 2000.

Short Form In SMS

Full word in sms

Short word in sms

1)And

1)n

2)Because

2)coz

3)You

3)U

4)Love

4)Luv

5)Miss

5)Miz

6)Busy

6)Bz

7)For

7)4

8)Before

8)B4

9)The

9)De

10)Be

10)B

RADIO CORPORATION OF AMERICA

Definition:

RCA Corporation, founded as Radio Corporation of America, was an electronics company in existence from 1919 to 1986. Currently, the RCA trademark is owned by the French conglomerate Thomson SA through RCA Trademark Management S.A., a company owned by Thomson. The trademark is used by Sony Music Entertainment and Thomson SA, which licenses the name to other companies like Audiovox and TCL Corporation for products descended from that common ancestor.


Function:

Establishment

The incorporation of the assets of Marconi Wireless Telegraph Company of America (including David Sarnoff), the Pan-American Telegraph Company and those already controlled by the United States Navy led to a new publicly-held company formed by General Electric (which owned a controlling interest) in 1919. The subsequent cooperation among RCA, General Electric, United Fruit, Westinghouse Electric Corporation, and AT&T laid the groundwork for significant developments in point-to-point and broadcast radio, including the new National Broadcasting Company. The Navy turned over to RCA the former American Marconi radio stations appropriated during the war. Admiral Bullard received a seat on the RCA Board of Directors for his efforts in establishing RCA. The end result was government-created monopolies in radio for GE and Westinghouse and in telephone for AT&T.

The Navy's rationale that radio frequencies were limited and needed to be appropriated and put in use before other countries, primarily Great Britain, monopolized them first soon collapsed with the discovery in the mid-1920s of the practicality of the shortwave band for long-distance transmissions. The first head was Owen D. Young. At this time, David Sarnoff became general manager. RCA's charter required it be mostly American owned. The company became responsible for marketing GE and Westinghouse's radio equipment, and in a subsequent deal it also acquired the patents of United Fruit and Westinghouse in exchange for ownership stakes in those companies. As time passed, the company secured a large number of patents, including the superheterodyne concept. Some of RCA's early radios were designed so as to prevent the internals from being reverse-engineered.

Over the years it continued to operate international telecommunications services, under the subsidiary RCA Communications, Inc. and later RCA Global Communications.

Broadcast expansion

By 1926, the market for commercial radio had expanded significantly, and RCA purchased the WEAF and WCAP radio stations and networks from AT&T, merged them with the already-owned WJZ (the predecessor of WABC) New York to WRC (presently WTEM) Washington chain, and formed the National Broadcasting Company (NBC).

Phonograph

In 1929, RCA purchased the Victor Talking Machine Company, then the world's largest manufacturer of phonographs (including the famous "Victrola") and phonograph records. This included a majority ownership of the Victor Company of Japan, or JVC. The new subsidiary then became RCA-Victor. With Victor, RCA acquired New World rights to the Nipper trademark. RCA Victor produced many radio-phonographs and also created RCA Photophone, a sound-on-film system for sound films that competed with William Fox's sound-on-film Movietone and Warner Bros. sound-on-disc Vitaphone.

RCA began selling the first electronic turntable in 1930. In 1931, RCA Victor developed and released the first 33⅓ rpm records to the public. These had the standard groove size identical to the contemporary 78 rpm records, rather than the "microgroove" used in post-World War II 33⅓ "Long Play" records. The format was a commercial failure at the height of the Great Depression, partially because the records and playback equipment were expensive, and partially because the audio performance was poor (tracking ability depends upon, among other things, the stylus's radius of curvature, and it would require the smaller-radius stylus of the microgroove system to make slower-speed records track acceptably). The system was withdrawn from the market after about a year. (This was not the first attempt at a commercial long play record format, as Edison Records had marketed a microgroove vertically recorded disc with 20 minutes playing time per side the previous decade; the Edison long playing records were also a commercial failure.)

In 1930, RCA became a crucial and key tenant in the yet to be constructed landmark building of the Rockefeller Center complex, 30 Rockefeller Plaza, which from 1933 became known as the RCA building, now the GE Building. This critical lease in the massive project enabled it to proceed as a commercially viable venture.


Tuesday, September 1, 2009


 

TWISTED PAIR


 

ADVANTAGES

DISADVANTAGES

  • It is a thin, flexible cable that is easy to string between walls.
  • Twisted pair's susceptibility to the electromagnetic interference greatly depends on the pair twisting schemes (usually patented by the manufacturers) staying intact during the installation. As a result, twisted pair cables usually have stringent requirements for maximum pulling tension as well as minimum bend radius. This relative fragility of twisted pair cables makes the installation practices an important part of ensuring the cable's performance.
  • Because UTP is small, it does not quickly fill up wiring ducts.
  • In video applications that send information across multiple parallel signal wires, twisted pair cabling can introduce signaling delays known as skew which results in subtle color defects and ghosting due to the image components not aligning correctly when recombined in the display device. The skew occurs because twisted pairs within the same cable often use a different number of twists per meter so as to prevent common-mode crosstalk between pairs with identical numbers of twists. The skew can be compensated by varying the length of pairs in the termination box, so as to introduce delay lines that take up the slack between shorter and longer pairs, though the precise lengths required are difficult to calculate and vary depending on the overall cable length.
  • UTP costs less per meter/foot than any other type of LAN cable
 


 


 


 

COLOXIAL CABLE


 

ADVANTAGES

DISADVANTAGES

  • the nature of the medium makes it highly

    immune to interference

  • slightly more expensive than twisted pair.
  • with a high signal-to-noise ratio, coaxial cable can support fairly high data rates
  • Thicknet is a significantly thicker cable, with a solid, inflexible core.
  • Over limited distances, coaxial cable can be pushed into the low gigabit per second (Gbps) range
  • It was much more difficult to pull than thinnet cable, and significantly more difficult to pull than twisted pair.


     


 


 


 


 


 


 


 


 


 


 


 


 


 


 


 

FIBER OPTIC CABLE


 

ADVANTAGES

DISADVANTAGES

  • Lower cost in the long run
  • High investment cost
  • Low loss of signal (typically less than 0.3 dB/km), so repeater-less transmission over long distances is possible
  • Need for more expensive optical transmitters and receivers
  • Large data-carrying capacity (thousands of times greater, reaching speeds of up to 1.6 Tb/s in field deployed systems and up to 10 Tb/s in lab systems)
  • More difficult and expensive to splice than wires
  • Signals contain very little power
  • Cannot carry electrical power to operate terminal devices. However, current telecommunication trends greatly reduce this concern: availability of cell phones and wireless PDAs; the routine inclusion of back-up batteries in communication devices; lack of real interest in hybrid metal-fiber cables; and increased use of fiber-based intermediate systems.

Sunday, August 30, 2009


TREE TOPOLOGY



Also known as a star bus topology, tree topology is one of the most common types of network setups that is similar to a bus topology and a star topology. A tree topology connects multiple star networks to other star networks. Below is a visual example of a simple computer setup on a network using the star topology.In the example picture if the main cable or trunk between each of the two star topology networks failed, those networks would be unable to communicate with each other. However, computers on the same star topology would still be able to communicate with each other.








MESH TOPOLOGY



A type of network setup where each of the computers and network devices are interconnected with one another, allowing for most transmissions to be distributed, even if one of the connections go down. This type of topology is not commonly used for most computer networks as it is difficult and expensive to have redundant connection to every computer. However, this type of topology is commonly used for wireless networks. Below is a visual example of a simple computer setup on a network using a mesh topology




Tuesday, August 11, 2009










UNSHIELDED








SHIELDED



Wednesday, August 5, 2009

Business to consumer(B2C),business to business (B2B),consumer to consumer(C2C)


Business-to-consumer




Business-to-consumer (B2C, sometimes also called Business-to-Customer) describes activities of businesses serving end consumers with products and/or services.


An example of a B2C transaction would be a person buying a pair of shoes from a retailer. The transactions that led to the shoes being available for purchase, that is the purchase of the leather, laces, rubber, etc. as well as the sale of the shoe from the shoemaker to the retailer would be considered (B2B) transactions.



Business-to-business




Business-to-business (B2B) describes commerce transactions between businesses, such as between a manufacturer and a wholesaler, or between a wholesaler and a retailer.

The volume of B2B transactions is much higher than the volume of B2C transactions. The primary reason for this is that in a typical supply chain there will be many B2B transactions involving subcomponent or raw materials, and only one B2C transaction, specifically sale of the finished product to the end customer. For example, an automobile manufacturer makes several B2B transactions such as buying tires, glass for windshields, and rubber hoses for its vehicles. The final transaction, a finished vehicle sold to the consumer, is a single (B2C) transaction.


Etymology


The term "business-to-business" was originally coined to describe the electronic communications between businesses or enterprises in order to distinguish it from the communications between businesses and consumers (B2C). It eventually came to be used in marketing as well, initially describing only industrial or capital goods marketing. Today it is widely used to describe all products and services used by enterprises. Many professional institutions and the trade publications focus much more on B2C than B2B. This is a strange development as most sales and marketing people work in B2B.




Consumer-to-consumer




Consumer-to-consumer (C2C) (or citizen-to-citizen) electronic commerce involves the electronically-facilitated transactions between consumers through some third party. A common example is the online auction, in which a consumer posts an item for sale and other consumers bid to purchase it; the third party generally charges a flat fee or commission. The sites are only intermediaries, just there to match consumers. They do not have to check quality of the products being offered.




Examples of C2C



This type of e-commerce is expected to increase in the future because it cuts out the costs of using another company. An example on how it could change in the future from Management Information Systems, if you are driving around in a car, someone having a garage sale can transmit to your GPS advertising their garage sale. This will reach a larger population than just signs.



  • No quality control

  • No payment guarantee

  • Hard to pay for using cheques, ATM cards, etc. but in the future this is likely to change.


Universities


C2C are becoming more popular amongst students in universities because these are large communities in the same geographical region that are low on money. So they are looking for deals very often and these kinds of websites offer this. Universities themselves set up places for students to sell textbooks and other stuff to other students, you can even advertise that you are subletting your apartment. An example of this from above is Tiger books and Dalhousie University Classifieds, both of these are put together by the school itself for the students