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CO639/2020
UNIVERSITY OF KENT
FACULTY OF SCIENCES
LEVEL 6 EXAMINATION
SCHOOL OF COMPUTING
Electronic Commerce
Two hours
The paper contains THREE questions. Answer ALL the questions.
- 2 -

1. (a) Use the following PHP script to demonstrate why the content is
dynamic.

if(date("a") == "am")
echo "Good morning";
else
echo "Good afternoon";
?>

[2 marks]
(b) Elaborate why dynamic content is important to e-Commerce. [3 marks]
(c) Elaborate the PHP communication by providing more details of
each numbered step in the following University of Kent
deployment.


[5 marks]
(d) Ordering music items from an on-line store starts with a customer
first browsing the catalogue, selecting the music items to order
and then submitting the order. This is followed by entering the
payment details, which are subject to validation. If validation fails a
message is displayed to indicate that payment was unsuccessful
and the order transaction is cancelled. Otherwise the payment is
deducted from the account, the items delivered and a receipt is
sent by email.
(i) Design a software structure for this system. Specify the
functions that you need to implement for each functionality of
this system. [4 marks]

- 3 -

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(ii) Consider a function that allows a customer to browse the
catalogue and add items to the shopping cart. Write an
outline of PHP pseudo-code (that does not have to be
grammatically strict and correct) that implements this
function. State any assumptions you have made, for
example, that the user has already been authenticated, etc. [6 marks]
2. Using the following PHP script to demonstrate how the server-side
session file works together with the client-side cookie. Draw a
schematic diagram in your answer. Your answer should also include
the confidentiality issue.

session_start();
if(isset($_SESSION['count']))
$count = ++$_SESSION['count'];
else
$count = $_SESSION['count'] = 1;
echo "You've visited this page {$count} times";
?>
[20 marks]
3. Assume a service has a predictable daily demand where the peak
requires 500 servers at noon but the trough requires only 100 servers
at midnight, as shown in Figure 1.

Figure 1

(a) If the average use over a whole day is 300 servers, calculate the
server hours over the whole day (shaded area under the curve); [2 marks]
(b) Calculate the actual utilisation; [3 marks]
(c) Elaborate whether you recommend the service provider to move to
the cloud based on the above calculation; [5 marks]
(d) Explain which are the key features of Cloud Computing exploited
by this example. [10 marks]