Bream Bay College: NCEA Level 2 Digital Technologies 91371 (2.44)
Level 2 Digital Technologies 91371 (2.44)
Digital Technologies 91371 (2.44): Demonstrate understanding of advanced concepts
from computer science (4 Credits)
Achievement
Achievement with Merit
Demonstrate understanding of
advanced concepts from computer
science involves:
Demonstrate in-depth
understanding of advanced
concepts from computer science
involves:
Demonstrate comprehensive
understanding of advanced
concepts from computer science
involves:
 comparing and contrasting
different ways in which
different types of data can be
represented using bits and
discussing the implications
 evaluating a widely used system
for compression coding, error
control coding, or encryption
 describing ways in which
different types of data can be
represented using bits
 describing the concept of
encoding information using
compression coding, error
control coding, and encryption;
and typical uses of encoded
information
 providing examples from
human-computer interfaces that
illustrate usability heuristics.
 discussing how a widely
used technology is enabled
by one or more of
compression coding, error
control coding, and
encryption
Achievement with Excellence
 suggesting improvements to a
given human-computer interface
based on an evaluation in terms
of usability heuristics.
 evaluating a given humancomputer interface in terms
of usability heuristics.
Candidate introduction
You will produce a report that demonstrates understanding of advanced concepts from computer
science.
There are three main concepts of computer science which are defined in the standard:
 data representation
 encoding information
 human-computer interaction (HCI).
You should demonstrate your understanding of these concepts as they relate to your own personal
experience of computing. Try to avoid copying and pasting material. If you must, make sure you
reference the copied material.
You will find a suitable list of usability heuristics at
http://www.useit.com/papers/heuristic/heuristic_list.html.
Candidate guidance for producing the report
Your report will have three sections:
1. Data Representation. In this section, you will produce the information related to data representation.
2. Encoding. In this section, you will produce the information related to encoding information.
3. Usability. In this section, you will produce the information related to usability heuristics.
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Bream Bay College: NCEA Level 2 Digital Technologies 91371 (2.44)
Definitions
The following definitions might be useful when you are writing your report:
Advanced concepts from computer science are the concepts of data representations, encoding, and
usability heuristics.
Data representations may include binary representations for signed and unsigned integers, real
numbers, characters, text, colours, sound, and images.
Reference Materials
You may find the following useful:
Bell, A., Duggan, E., Hoy, B. & van Praag, G. (2013). Digital technologies learning workbook. Auckland,
New Zealand: ESA Publications.
Bell, T., Morgan, J., et al. (2014). Computer science field guide beta.
http://www.csfieldguide.org.nz/index.html
Data Representation
1. Explain what a bit is and how it is stored on a computer or device.
2. Explain how bits can be used to store numbers.
3. Explain how numbers (and therefore bits) can be used to store other things like characters,
colour, images and sound.
4. Look at the different ways computers store numbers (see the definitions section above). Explain
the difference between storing integers and floating point numbers and compare and contrast
them. Discuss the implications of using these two methods. Or, examine the difference between
8 bit and 16 bit integers.
5. Describe how computers store different information such as characters. ASCII and UNICODE are
two such methods whose implications could be discussed. Another alternative would be to look
at encoding colour information.
When using examples to demonstrate your understanding, make sure you link them to yourself so
that authenticity is clear to the marker. For example use your name for character encoding and your
date of birth for number encoding or something similar that is personal to you.
Encoding Information
1. Write a paragraph describing how information can be encoded using error control coding. List
and briefly describe a few typical uses of error control coding.
2. Write a paragraph describing how information can be encoded using compression. List and
briefly describe a few typical uses of compression.
3. Write a paragraph describing how information can be encoded using encryption. List and briefly
describe a few typical uses of encryption.
4. Discuss a widely used technology and how it is enabled by one or more of these encodings.
5. Evaluate a widely used system for one of these encodings.
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Bream Bay College: NCEA Level 2 Digital Technologies 91371 (2.44)
Usability Heuristics
In this section, make use of the Nielsen usability heuristics as these are an industry standard. Include a
reference.
1. Describe each heuristic in your own words explaining what it means. List an example from your
experience where this heuristic has not been followed and an example where it has been
followed. If possible provide screen shots.
2. Choose a user interface and evaluate it using these heuristics. This means discussing the user
interface using each heuristic. You could combine this with part 1 above for descriptions of each
heuristic in your chosen interface.
3. Suggest improvements to your chosen user interface based on your evaluation of each heuristic.
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