Intro to Ubiquitous Computing

Question 1

What is mobile computing?

Answer 1

Mobile computing is computation wherein the change of location of the device affects the output of said device. Location must be one of the application’s inputs to be truly mobile!

Question 2

What is the difference between a mobile app and a truly mobile app?

Answer 2

A mobile app may compute in different locations, but will not be affected by the location parameter. A truly mobile app will be affected.

i.e. A banking app may be mobile, but will not be affected by the location. It is mobile purely for the sake of convenience.

Question 3

What is meant by ‘ubiquitous’ computing?

Answer 3

Ubiquitous computing is context-aware computing, wherein the inputs to the device are all of its surroundings - i.e. environment, user, resources.

Question 4

How can ubiquitous computing devices take in data from its surroundings?

Answer 4

By using sensors - i.e. location sensors (GPS), motion sensors, temperature sensors etc.

Question 5

What do we mean when we say that mobile and ubiquitous computing is ‘volatile’?

Answer 5

They experience continuous, sometimes incremental change in the environment over time, thereby making the output sensitive and unpredictable.

Question 6

What are the main differences between wired and wireless networks?

Answer 6

Wireless networks use no cables of any kind - instead opting for radio waves - and therefore need to convert information signals into a form suitable for air transmission.

Question 7

What is meant by ‘throughput’?

Answer 7

A measure of how many units of information can be processed within a given period of time.

Question 8

What is meant by ‘bandwidth’ in relation to a network?

Answer 8

A measure of how much data can be transferred in a given unit of time.

Question 9

What is meant by ‘latency’ in relation to a network?

Answer 9

How much time it takes for the data to transfer across the network. Networks with a long delay have high latency, while those with short delays have low latency.

Question 10

What is Radio Frequency Identification (RFID)?

Answer 10

RFID is a form of wireless communication that uses coupling of the frequency of an object with an RFID tag to uniquely identify an object.

Question 11

What is the difference between passive and active RFID?

Answer 11

Passive RFIDs do not have their own power source, and are instead inducted by the RFID reader. Active RFIDs have their own power source.

Question 12

What are the three common implementations of RFID?

Answer 12

UHF, HF and LF, referring to Ultra-High, High and Low-High frequency respectively. No idea why Ultra-High makes UHF, and Low-High makes just LF.

Question 13

What is the difference between the three common implementations of RFID, from high to low?

Answer 13

Ultra-High has a larger range and frequency, but uses more power, making it best for applications such as in drivers’ licenses.

As we reach Low-High, we have a lower range and frequency, but conserve more power, making it more suitable for credit cards or livestock tracking.

Question 14

What is a Wireless Personal Area Network (WPAN)?

Answer 14

WPAN is a network classifier for a short-range network with a low data rate.

Question 15

What is a common example of WPAN?

Answer 15

Bluetooth
Infrared
Zigbee

Question 16

What is a Wireless Local Area Network (WLAN)?

Answer 16

WLAN is a network classifier for a network roughly the size of a small building, with a high data rate and moderate latency.

Question 17

What is a common example of WLAN?

Answer 17

Local Wi-Fi

Question 18

What standards do WLAN networks typically conform to?

Answer 18

IEEE is a set of network standards that govern wireless transmission methods.

Question 19

Roughly how much range does a WLAN have?

Answer 19

100 meters.

Question 20

Roughly how much range does a WPAN have?

Answer 20

Typically around 10 meters, however in certain cases (typically Bluetooth) this number can reach anywhere from 1 to 100 meters.

Question 21

What is a Wireless Neighbourhood/Metropolitan Area Network (WNAN)?

Answer 21

WNAN and WiMAX are two terms for a network classifier that describes a network that covers a massive range of users, with an extremely high data rate.

Question 22

Roughly how much range does a WNAN have?

Answer 22

~50 kilometers.

Question 23

What is a common example of a WNAN?

Answer 23

WiMAX is a WNAN network typically used for local cellular data.

Question 24

What is a Wireless Wide Area Network (WWAN)?

Answer 24

WWAN is a network classifier that describes a network with a near-omnipresent range, with massive bandwidth too.

Question 25

What is a common example of a WWAN?

Answer 25

Cellular mobile data.

Question 26

Roughly how much range does a WWAN have?

Answer 26

There is no ballpark estimate, as WWANs typically refer to satellite connections which may extend tens of thousands of meters away.