Question:    I couldn't find the slides of the 3260 lecture notes on the course website, is it possible that you put them on the website so that I can print my own copy. This is because I am not comfortable with the 2 slides per page printout which is provided in the co-op.

Answer:     Sorry. The School policy is to channel all printing of class notes to the Coop. This will economize on paper and printing from the School machines.
 

Question:    The price that the Co-op charges for the course readings seems to be higher than the normal copying costs.  Why is that the case?

Answer:     The Co-op needs to pay permission fees to the respective publishers for copying and including their articles.
 

Question:    Will you put the model answer for the tutorial questions on the website?

Answer:      Sorry. There is no model/universal answer for the questions. Most of the feasible answers are already discussed during the tutorials.

Question:    Please explain "Query Scope".

Answer:      The Singapore Exchange lists shares of many companies. An investor who is only interested in manufacturing shares can limit his queries to the list of manufacturing shares. An investor who is interested in many categories of shares - manufacturing, services, transport, and finance - has a much wider query scope.

Question:    What's the "Content" for renting movies? And why not the service modes?

Answer:      Content refers to information (or indeed, products) that is presented or delivered to customers. In this case, the product is the movie, not the interactions at the point of sale. Bear in mind that the purpose of telecommunications is to facilitate communications or exchange of information/data.  So you have to ask yourself: what is the purpose of the system?  What does the system deliver to users?

Question:    How do we justify that movie and video conferencing is streamy or bursty?

Answer:      If you consider the consumption process itself, nothing is bursty.  A phone call that lasts for several seconds is streamy in those few seconds.  We suggest that the consumption of movie is rather bursty because a normal viewer watches movies only once in a while (unlike, e.g., a security control system, which is turned on almost every minute).  

Question:    Responsiveness: Store and Forward.

Answer:      If the movie is transmitted into a buffer, and stored and then shown when all the bits are collected, that would be store and forward. If the movie bits were shown as they were received, that would not be store and forward, but the quality would be lower. This seems to be an exception, where store and forward gives higher quality.

Question:    What is multi-path?

Answer:      A signal may be bounced off when they hit some other buildings or objects. When these bounced-off signals superimpose with the original stream of signal, distortion may occur.

Question:    What is frequency re-use?

Answer:      Electromagnetic signal loses power as it travels longer distance. If a certain frequency is being used in a region (e.g., cell), then other regions can use the same frequency without worrying about interference because the signal cannot go that far.

Question:    What is line-of-sight?

Answer:      Laptop-to-laptop data transfer is line-of-sight. But you must be able to see each other with your eyes.

Question:    Please elaborate on free space loss. Is it considered an advantage or disadvantage?

Answer:      It is not good in the sense that signals become weaker and weaker as distance increases. So you need more power to transmit the signal if you want to serve a large region. But it can be advantageous because it facilitates frequency re-use. So, again, it may not be absolutely good or bad. Whether it's advantageous or disadvantageous depends on your application.

Question:    Why marginal cost does not increase as variable cost increases?

Answer:      Variable cost consists of two components: (1) number of units produced; (2) unit cost. An increase in variable cost may due to increases in number of units, instead of unit cost. In this case, marginal cost does not necessarily change.

Question:    What is PT&T?

Answer:      Post, Telephone and Telegraph administration. One of the many national bodies responsible for providing communications services in a particular country. For example, TAS in Singapore in the past.

Question:    What is Network Externality/Effect?

Answer:      Consumption benefit of a product increases as the number of other uses increases.

Question:    What is meant by demand is inelastic away from tipping point and very elastic around tipping point?

Answer:      When the demand is away from the tipping point, even if your price is low, they don't buy your products. So inelastic. But when the demand is near the tipping point, it will be changed.

Question:    What is GPRS?

Answer:      A GSM data transmission technique that does not set up a continuous channel from a portable terminal for the transmission and reception of data, but transmits and receives data in packets. It makes very efficient use of available radio spectrum, and users pay only for the volume of data sent and received.

Question:    What is GPS?

Answer:      Global Positioning System. A system of satellites, computers, and receivers that is able to determine the latitude and longitude of a receiver on Earth by calculating the time difference for signals from different satellites to reach the receiver.

Question:    What is CDMA?

Answer:      Code Division Multiple Access. A form of multiplexing where the transmitter encodes the signal using a pseudo-random sequence which the receiver also knows and can use to decode the received signal. Each different random sequence corresponds to a different communication channel. E.g., Motorola uses CDMA for digital cellular phones. 

Question:    What is AT&T?

Answer:      American Telephone and Telegraph, Inc. One of the largest US telecommunications providers.