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Monday, March 7, 2011

Communication & Network

The Theory of Communication Network

The idea of a network first emerged with perhaps the oldest form of organized communication: the postal service. Most communication networks, even modern ones, share many of its aspects.

  • A user writes a letter, serving in the communications context as the message source.
  • This message is sent to the network by delivery to one of the network's public entry points. Entry points in the postal case are mailboxes, post offices, or your friendly mailman or mailwoman picking up the letter.
  • The communications network delivers the message in the most efficient (timely) way possible, trying not to corrupt the message while doing so.
  • The message arrives at one of the network's exit points, and is delivered to the recipient (what we have termed the message sink).

Wireless Connection

Wi-Fi

A wireless network uses radio waves, just like cell phones, televisions and radios do. In fact, communication across a wireless network is a lot like two-way radio communication.


International symbol for Wi-Fi


Here's what happens!!

  1. A computer's wireless adapter translates data into a radio signal and transmits it using an antenna.
  2. A wireless router receives the signal and decodes it. The router sends the information to the Internet using a physical, wired Ethernet connection.

How iTunes Mobile Works

  • Apple's iPod and iPhone dominate their respective product categories. So it's perhaps no surprise that iTunes, the software that helps those products perform much of their magic, is also virtually ubiquitous. Although iTunes began as a program for desktop computers, it's now available on some mobile devices, too.

How iTunes Mobile Works?


What Is Bluetooth?

Bluetooth wireless technology is built into electronic gadgets and lets you talk and share information like voice, music and videos, wirelessly.



  • Well it isn't some strange form of tooth decay as you might initially imagine. Bluetooth is the name of a new technology that is now becoming commercially available. It promises to change significantly the way we use machines.

1. Take a look around

Look around you at the moment, you have your keyboard connected to the computer, as well as a printer, mouse, monitor and so on. What (literally) joins all of these together?, they are connected by cables. Cables have become the bane of many offices, homes etc. Most of us have experienced the 'joys' of trying to figure out what cable goes where, and getting tangled up in the details. Bluetooth essentially aims to fix this, it is a cable-replacement technology.


2. How?

Bluetooth is a standard for a small , cheap radio chip to be plugged into computers, printers, mobile phones, etc.A Bluetooth chip is designed to replace cables by taking the information normally carried by the cable, and transmitting it at a special frequency to a receiver Bluetooth chip, which will then give the information received to the computer, phone whatever.

3. How about..?

That was the original idea, but the originators of the original idea soon realised that a lot more was possible. If you can transmit information between a computer and a printer, why not transmit data from a mobile phone to a printer, or even a printer to a printer?. The projected low cost of a Bluetooth chip, and its low power consumption, means you could literally place one anywhere.

4.  The Future
Whatever the ideas, Bluetooth is set to take off. To be honest it's going to be forced down the consumers necks, whether they want it or not, as too many companies have invested in it. This website is generally geared towards the technical issues surrounding Bluetooth, and its implementation in real life.




What is GPS?

The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense.

How it works?

GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to earth. GPS receivers take this information and use triangulation to calculate the user's exact location. Essentially, the GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is.



How accurate GPS is? 

Today's GPS receivers are extremely accurate, thanks to their parallel multi-channel design. Garmin's 12 parallel channel receivers are quick to lock onto satellites when first turned on and they maintain strong locks, even in dense foliage or urban settings with tall buildings. Certain atmospheric factors and other sources of error can affect the accuracy of GPS receivers. Garmin® GPS receivers are accurate to within 15 meters on average.

GPS Gazette




Broadband

The term broadband refers to a telecommunications signal of greater bandwidth, in some sense, than another standard or usual signal (and the broader the band, the greater the capacity for traffic). Different criteria for "broad" have been applied in different contexts and at different times. Its origin is in radio systems engineering, but became popularized after MediaOne adopted it as part of a marketing campaign in 1996 to sell their high speed data access.

Maxis Broadband

Celcom Broadband

DIGI Broadband

P1 Wimax Broadband


Introducing to you, the latest broadband 4G package!

Priority Broadband
OverviewPackagesCoverage
  • Discover new worlds with blazing fast connections and seamless surfing like nothing you've ever experienced before. 
  • Wireless broadband in its most evolved form, P1 4G sets a new surfing standard and brings mobile freedom to all consumers. 
  • It unwired homes, offices and hangouts while freeing the way you live, work and play.
Greater Speed
• WiMAX offers faster and more consistent speeds than most wireless technologies such as WiFi, EDGE, UMTS (3G) and HSDPA (3.5G).
Wider Coverage
• WiMAX coverage is up to hundreds of times the coverage range of WiFi.
Excellent Quality of Service (QoS)
• Designed with cutting-edge QoS technology, WiMAX is dynamically optimised to support seamless and high quality streaming    of voice, video and data downloads.
Protected Privacy and High Security
• WiMAX is enhanced with advanced data encryption to ensure worry-free wireless surfing sessions


Priority Broadband
OverviewPackagesCoverage
E-Billing : FREE (Or RM5 monthly for a paper bill)
  • Modem is on rental basis. RM50 Modem Return Rebate will be credited in the last bill when modem is returned in good working condition.
  • RM 200 administrative fee is chargeable if the service is terminated within 12 months.
  • Terms and conditions apply.


References :


Computing Essentials (Complete 2010), Linda & Timothy O'Leary





Communications and Networks

Computer Usage @ work : Agriculture

The worlds dependent on the agriculture industry is enormous. The demand is continually increase and allow this industry growing very high. Although people have worked in agriculture for more than 1000 years, technology could not be separated as it can be apart to foster agriculture business.

Almost all companies have many acres of land and they must maintain and its not feasible for every farmer to take frequent trips around the property to perform basic task such as watering soil in the absence of raining. By providing several solutions, the irrigation process is automated by sensors detect how much rain has fallen recently as well as whether the soil is need of watering. The sensors send data to computer that process and decided when an how much to water. Many automated home irrigation system also are programmable and use rain sensors, which keep the irrigation system from turn on o turn off when rainfall occurs.

In addition to keeping the irrigation system. Computer can utilize by using sensors to analyze the condition of crops in the field and determine whether pests or disease are affect by the crops. If detect, computer send a notification to the appropriate individual to make corrective action.


Conclusion
  • The using of networks and communication made farmer to do job ease.
  • Wireless access throughout the farm also allows farmer to monitor their farms and communicate with colleague from remote locations.


sources: scsite.com/dcf2011/ch8/work and agriculture

Secondary Storage

Secondary Storage Media

 Hello Guys!

Good day friends!
 
In today's lesson, we will be looking at secondary storage media. 
 
This became necessary due to the fact that primary storage devices such as RAM and ROM are limited in size and are temporary , while secondary storage is permanent and can be used for backup purposes and future use. 
 
A comparison can be made among the variety of secondary storage devices in respect to their portability, speed and capacity.
 
1.Storage capacity
Storage capacity is the amount that a particular storage medium can hold. Large capacity storage devices are more preferred for many sophisticated programs and large database.


2.Access speed
This refers to the average time needed to locate data on a secondary storage device. Access time is measured in milliseconds.

3.Portability
 This refers to the ease and accessibility of a device to transfer information from one computer to another.


For your information, every secondary storage device requires its own drive.Besides, 
Storage devices record and retrieve data, instructions and information to and from storage media. Examples are floppy disk drive, hard disk drive, compact disc drive.


Secondary storage devices fall into two main categories:
  • Direct Access Storage Devices (DASD)
  • Serial/Sequential Access Storage Devices (SASD)
  Storage media comprised of many types which is
  • Floppy diskettes
  • Hard disks
  • Magnetic tape
  • USB flash drive
  • CD-ROM (Compact Disc Read Only Memory)
  • WORM (Write Once Read Many)
  • Compact Disc Recordable (CD-R)
  • Compact Disc Rewritable (CD-RW)
  • Digital Versatile/Video Disc (DVD)
  • Flash memory
Generally,compact Disc also known as optical disc.The Holographic Versatile Disc (HVD) is an optical disc technology developed between April 2004 and mid-2008 which can store the same amount of information of between 20 and 200  Blu-ray discs. 
 
Blu-ray Disc
A red laser is used as the reference beam to read servo-information  from a regular CD-style aluminum layer near the bottom. Servoinformation is used to monitor the position of the read head over the disc, similar to the head, track, and sector information on a conventional  hard disk drive. On a CD or DVD.

How Holographic Versatile Discs (HVD) Work?

Holography is a method of recording patterns of light to produce a three-dimensional object. The recorded patterns of light are called a hologram




 HVD offers several advantages over traditional storage technology. First and foremost,HVDs can ultimately store more than 1 terabyte (TB) of information  that's 200 times more than a single-sided DVD and 20 times more than a current double-sided Blu-ray. 

This is partly due to HVDs storing holograms in overlapping patterns, while a DVD basically stores bits of information side-by-side. HVDs also use a thicker recording layer than DVDs an HVD stores information in almost the entire volume of the disc, instead of just a single, thin layer.
 
Volumetric recording method
DVD vs. HVD: Recording-layer depth
 
The other major boost over conventional memory systems is HVD's transfer rate of up to 1 gigabyte (GB) per second  that's 40 times faster than DVD. 

An HVD stores and retrieves an entire page of data, approximately 60,000 bits of information, in one pulse of light, while a DVD stores and retrieves one bit of data in one pulse of light.
 
 
References ;
 
 Credit to;

Communications and Networks

Should you worry about Cell Phone, Cellular Antenna, and Wi-Fi Device Radiation ?

Billions of people use cell phones throughout the whole world, from the population 80% accessed to cell phone services from antenna. Wi-Fi signals for example, making business, public areas and also for home purpose has broadened is function efficiently. These numbers of users are expected to increase sharply in the next coming years, and many users are concern about potential health effect from cell phones, cellular antenna and Wi-Fi devices. Some users making a judgment by suffer rare illness have filled lawsuit against cell phones companies. Therefore, the cases usually are lost due to lack of scientific evidence towards the issue of the phone to illness.

Debates are take place in communities to discuss over placement of cellular antennas when everything breach the Act of 1996 when local government prohibit from considering health effects when making decision about cellular antenna placement.

Whatever it is, every party agree that no studies conclusively demonstrate negative health effects from cell phones, cellular antenna, and Wi-Fi devices because the technology is too new and take some time to experiment the effect.

Sources: Ethics & Issue, Shelly Cashman Series. 2011 (Text Book)

MIDI




A musical instrument digital interface (MIDI) sound card is a piece of computer hardware that allows a user to connect musical instruments and similar devices through a MIDI connector to a computer. This is typically done to use a computer to record music, especially for use in a MIDI format, and the sound card may also often act as a standard sound card as well, allowing connection of microphones, speakers, and similar devices. A MIDI sound card can potentially be built onto a computer’s motherboard, but is often a separate device installed onto the motherboard inside of the computer case.

MIDI is a standard used in a number of different industries as a way to get audio information onto a computer hard drive. This audio data can then be recorded, edited, and used in a number of different applications, depending on what is needed by a computer user. A MIDI sound card is an audio device that uses this type of interface and is installed onto a computer’s motherboard, which allows a musical instrument, often a keyboard, to be connected to the computer. The instrument can then be used as an input device to create music or audio information that can then be saved onto the computer.

A MIDI sound card has often been used in creating digital music. It will not typically actually record audio information, as the device used for input does not really play music into the computer. Any audio information is not sent as waves of sound but as digital information indicating pitch, volume, tempo, and other pieces of information that can be translated to audio sound through the use of an audio editing program or similar software. This means the resulting audio from using a MIDI device typically sounds somewhat synthesized and may sound innately digital or computerized in nature.

Much like other types of sound cards, a MIDI sound card will typically allow a user to connect speakers and a microphone to the computer as well. Sometimes multiple sound cards are used to allow the MIDI card to be solely for input of audio, and a separate card to work as output to speakers or headphones. The input device used with a MIDI sound card is typically a keyboard, which will have a MIDI connector that runs from a plug on the keyboard to the sound card. These may be standard keyboards that can also produce music or specialized MIDI keyboards that do not make music and only serve as a digital audio input device.

http://www.canmoremedia.com/basic-midi-connections.html

Imaginary Interface Could Replace Screens and Keyboard

Can you imagine our imagination can replace screens and keyboard? Sounds like ridiculous right? But when I'm trying to search a new technology for today, the title "Imaginary Interface" attract me to get closer with this topic. Here, I'll give you some summary about the "Imaginary Interface".


A user draws an imaginary line in the operating plane of the Imaginary Interfaces device.


The 'Imaginary' Interface device combines a camera and comp
uter to see and then interpret gestures. Researchers are experimenting with a new interface system for mobile device that could replace the screen and even the keyboard and gestures supported by our visual memory.

To operate Imaginary Interfaces, people use two basic commands. Making an 'L' shape with one's non-dominant hand (typically the left) 'opens up' a two-dimensional plane where the finger tracing interaction will take place; the L acts as the lower left corner of the plane in this example.

Users can 'pinch' with the dominant hand to select a point in space on this plane that can serve a function. As an easy frame of reference, a grid can be visualized based on the lengths of the finger and thumb in the L gesture as a 'Y' and 'X' coordinate, respectively. Pinching at approximately 3, 2 – or three finger-lengths up and two thumb-lengths over – could press a virtual button.




The Imaginary Interfaces device


With 'Imaginary' Interfaces, however, there is nothing to see, short term visual memory instead serves as the reference, like mimes, people can mentally record and 'touch' these make-believe elements.


Now, the innovation technology becoming faster and sometimes people cannot catch the technology products because of the fastest changing. But with the imagination, all people seems like they are in updated.

See you next time!


References:

Credit to: Hasso Plattner Institute

Future Input Devices

Hai everybody! 
FIRSTLY,do you want to know more about the future input devices? Lets Check it out!

Do you imagine that our SKIN can be input devices in the future? it is certainly no longer plausible right? 


Chris Harrison and a team of researchers are showing off a method of  ”Using your Arm, Hand and Skin as an input device“.Its sounds weird right? but, it can be reality in our life someday..who's knows?



Skin Input-Hand Input





Skin Input-Arm Input

For your information,they have been able to workout a technique that detects where the tap touches and use that to control phones and music players and computers. As a result, An arm band worn by the user picks up acoustic signatures created by tapping on your arm with the other hand, or taping your fingers and thumb together on the same hand. They’re achieving accuracies in the 82-97% range but it gets even better.

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As a conclusion,

“The human body is the ultimate input device,” said Chris Harrison...

 The usage of this technology human being will start to step in the era of robotic life style.


SECOND, the second input devices is mouse..In the future, it will be mouseless.....Believe it or not??
"MOUSELESS"= Without MOUSE

Mouseless
Mouse Evolution
But this could all change in the Future. The innovator Pranav Mistry comes with yet another
proof concept of computer input that could change the way we communicate with our PCs. The Mouseless invention removes the requirement of having a physical mouse altogether but still provides the intuitive interaction of a physical mouse that we are familiar with.
As Pranav Mistry said,
Mouseless consists of an Infrared (IR) laser beam (with line cap) and an Infrared camera. Both IR laser and IR camera are embedded in the computer. The laser beam module is modified with a line cap and placed such that it creates a plane of IR laser just above the surface the computer sits on. 

The user cups their hand, as if a physical mouse was present underneath, and the laser beam lights up the hand which is in contact with the surface. The IR camera detects those bright IR blobs using computer vision.

The change in the position and arrangements of these blobs are interpreted as mouse cursor movement and mouse clicks. As the user moves their hand the cursor on screen moves accordingly. When the user taps their index finger, the size of the blob changes and the camera recognizes the intended mouse click.

VIDEOS: "Let's watch the demonstration" 







Visual Demonstration using invisible mouse



Reference:
Credit to; Pranav Mistry