July 2007 Volume 10 Number 3 - Educational Technology & Society

of each learning item in I in the form of (ESi, descriptioni), where encoded string ESi ∈ I , 2) an access database,
ADBorigin, which consists of a set of user access data (UIDi, {ESx, …, ESy}), where UIDi is a user’s identifier and
ESi ∈ I (for i=x, …, y), and 3) the notation of ‘*’ represents a class or concept in an encoded string ESi. To clarify
our discussion, an abstract example is introduced in the following sections.
(111)
Amplifiers
(1**)
Electrical Engineering
(11*)
Electric Circuits
(112)
Ohm’s Law
(121)
Ampere’s
Law
(12*)
Electromagnetism
(122)
Faraday’s Law
(211)
FET Circuit
Analysis
Figure 1. An example of a curriculum scheme
Example 1: For instance, the taxonomy information of the curriculum scheme is constructed as shown in Figure 1,
and the encoded access database ADBorigin is shown in Table 1. We use a unique encoded string to represent a
corresponding accessing-identifier, which is shown in the parenthesis in front of each accessing-identifier. In this
example scheme, the Electrical Engineering & Computer Science curriculum is given in three layers. The first layer
enumerates all the departments in this Electrical Engineering & Computer Science curriculum. The second layer lists
all the courses in the corresponding departments. The third layer itemizes all the learning items including in the
courses. For instance, the learning item ‘Wireless’ is encoded as ‘231’ in which the first digit, ‘2’, represent
‘Engineering Science’ at layer 1, the second, ‘3’, for ‘Data Communications’ at layer 2, and the third, ‘1’, for the
learning item ‘Wireless’ at layer 3.
Table 1. An example of user access database ADBorigin.
UID Items
U1 {231, 321, 322, 312}
U2 {111, 112, 212, 321, 322, 231}
U3 {322, 321, 111, 212, 231}
U4 {111, 222, 112, 212,211}
U5 {112, 211,212, 311}
U6 {111, 311, 212, 112, 231}
{231, 121, 321}
U7
Electrical Engineering & Computer Science
(21*)
Analysis of
Electronics Circuit
(212)
Operational
Amplifier Design
(221)
Registers
(2**)
Engineering Science
(22*)
Logic Design
(222)
Counters
(231)
Wireless
(23*)
Data
Communications
(31*)
Digital Circuit
(3**)
Computer Science
(32*)
Wireless
Communications
In this research, the frequent patterns are not restricted to the same layer (Han and Fu, 1999) but extend to the
different layers. For this reason, we increase the higher-level items in the access database ADBorigin to be an enriched
access database, ADBenriched. Whenever the lower-level items achieve a specified portion of count, the higher-level
items should be added into the enriched access database ADBenriched (shown in Table 2). For example, the access data
U6 in Table 2 contains the encoded items - 111, 112, 121, and 122, and these items fulfill the state we mentioned.
(232)
QoS
(311)
Accumulator
(312)
Multiplexer
(321)
Wireless LAN
(322)
Bluetooth
307