The document is a dissertation submitted by Le Phan Huu Bang to the Department of Computer Science at the National University of Singapore in 2008/2009 describing the design and development of a Knowledge Community System (K-Comm). The dissertation includes chapters on introducing knowledge and the need for knowledge sharing, reviewing existing literature, providing an overview of the K-Comm system and its features, and describing the implementation of K-Comm.

1. B. Comp. Dissertation
Design and Development of a
Knowledge Community System
By
Le Phan Huu Bang
Department of Computer Science
School of Computing
National University of Singapore
2008/2009

2. B. Comp. Dissertation
Design and Development of a
Knowledge Community System
By
Le Phan Huu Bang
Department of Computer Science
School of Computing
National University of Singapore
2008/2009
Project Number: H022560
Advisor: Assoc Prof Poo Chiang Choon, Danny
Deliverables:
Report: 1 Volume
Program: 1 CD
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3. Abstract
Today, when the technology is growing tremendously, knowledge has become a very
important part in our lives. The amount of knowledge that people need to obtain today is
more than ever before. As a result, being able to seek for the knowledge and information you
need in the fastest time is a critical but never easy task for every one of us.
In this project, we will try to design and develop a system to facilitate a Knowledge
Community (K-Comm) in which people can satisfy their needs of information and knowledge
in an easy and quick manner. The system will also serve as a knowledge-based social
network where individuals are encouraged and provided with a comfortable platform to share
and exchange their knowledge and expertise with other users.
We first do an online research and look for similar websites that have attempted to
either meet the demand of knowledge seeking or provide a social network platform to
facilitate exchanging of information for human relationship. After that, we come up with the
feature requirements and detailed specifications for the system that we are going to build.
Finally, we choose the appropriate framework and start the design and implementation of the
Knowledge Community System.
Subject Descriptors
M.0 Knowledge Acquisition
M3 Knowledge Maintenance
D.2.1 Requirements/Specifications
Keywords
Knowledge Community, Knowledge Areas, Tacit Knowledge, Knowledge
Management, Social Network
Implementation Software and Hardware
PHP, Ubuntu Linux, Firefox
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4. Acknowledgement
I would like to express my sincerest gratitude to my supervisor, Dr. Poo Chiang Choon,
Danny, for his invaluable guidance. I appreciate him for his time, ideas and advices with me
throughout the work of this project.
Special thank to Mr. Lek Hsiang Hui, for sharing his knowledge and programming
techniques with me. This precious experience helped me a great deal in this project.
I also would like to express my appreciation to Mr Cai Shao Jiang for helping out in the
implementation of the User Profiling package of the system.
Finally, I wish to give credit to those who have in one way or another given support in
the completion of this project.
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5. Table of Contents
Abstract.............................................................................................................................. i
Acknowledgement ............................................................................................................ii
Table of Contents ........................................................................................................... iii
Chapter 1 - Introduction ................................................................................................... 1
1.1 What is Knowledge ................................................................................................ 1
1.2 The Need of Knowledge Sharing ........................................................................... 1
1.3 Difficulties in Knowledge Sharing ......................................................................... 2
Chapter 2 - Literature Review .......................................................................................... 3
2.1 Yahoo and Google Answers ................................................................................... 3
2.2 Youtube .................................................................................................................. 3
2.3. Social Networks..................................................................................................... 4
2.4 Blogs and Forums ................................................................................................... 4
2.5 Knowledge Management Systems ......................................................................... 4
Chapter 3 - System Overview........................................................................................... 6
3.1 What is K-Comm.................................................................................................... 6
3.2 Features................................................................................................................... 6
3.2.1 Social Network Features.................................................................................. 6
3.2.2 Knowledge-based Features .............................................................................. 6
3.3 System Components ............................................................................................... 7
3.3.1 The User Profiling Package ............................................................................. 7
3.3.2 The Questions and Answers Package .............................................................. 8
3.3.3 The User Interface ......................................................................................... 11
Chapter 4 - Implementation ............................................................................................ 13
4.1 Elgg Framework ................................................................................................... 13
4.1.1 What is Elgg .................................................................................................. 13
4.1.2 Elgg Engine ................................................................................................... 13
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6. 4.1.2 Mapping from Elgg to K-Comm ................................................................... 16
4.2 Core Library ......................................................................................................... 17
4.2.1 Question Class ............................................................................................... 18
4.2.2 Category Class ............................................................................................... 18
4.2.3 Answer Class ................................................................................................. 19
4.2.4 Integration...................................................................................................... 20
4.3 Widgets ................................................................................................................. 20
4.4 User Interface ....................................................................................................... 21
4.5 Skill Level System ................................................................................................ 21
4.5.1 Requirements ................................................................................................. 23
4.5.2 Unsuccessful Attempts .................................................................................. 24
4.5.3 Our Approach ................................................................................................ 25
Chapter 5 - Conclusion ................................................................................................... 27
5.1 Summary............................................................................................................... 27
5.2 Difficulties and Limitations .................................................................................. 27
5.3 Recommendations for Further Work .................................................................... 27
References ...................................................................................................................... 29
Appendix ........................................................................................................................ 30
Functions provided for metadata ............................................................................ 30
Functions provided for annotations ........................................................................ 30
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7. Chapter 1 - Introduction
Before we can come up with the detailed requirements for our K-Comm System, we
first need to understand and delineate the definition of knowledge that we are using. In
addition, we also have to identify the need of knowledge sharing in the society we are living
now. Finally, we will point out what remain as difficulties in the process of sharing and
looking for the knowledge that we want.
1.1 What is Knowledge
Knowledge is defined in the Oxford English Dictionary as (i) expertise, and skills
acquired by a person through experience or education; the theoretical or practical
understanding of a subject, (ii) what is known in a particular field or in total; facts and
information or (iii) awareness or familiarity gained by experience of a fact or situation
(Wikipedia)
The knowledge we are going to deal with in this project is everything that a person
knows! It can be knowledge about a specific topic in a specialised field that the organization
is working on (e.g. How to create a Thread in Java) but it can also be knowledge about
general interest in which everyone is interested (e.g. Which bus can I take to go to NUS). It
can be both explicit and tacit knowledge. In general, we try to maximise and gather as much
as possible the knowledge potential of every individual in the organization or society
irrespective of the domains.
1.2 The Need of Knowledge Sharing
To begin with, it is inevitable that any company needs knowledge to survive. Where
does the knowledge come from? It comes from individual member who works for the
company. As a result, most of the companies are likely to have a high interest in encouraging
their employees to share the knowledge that they have with other people in order to benefit
everyone and in turn benefit the company.
Moreover, in a company or a community, more often than not, there are many repetitive
questions that are being asked every day. People are asking repetitive questions again and
again because they do not know that other people have already had the answers for those
questions and the reason behind this is people are unwilling to share what they know.
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8. Therefore, if we can find a way to encourage people to share the knowledge that they possess
and then capture it in a system, we will be able to avoid the repetitive questions and hence
will save a lot of time and efforts.
Finally, knowledge is growing by sharing. If we do not share, our common knowledge
will not grow. In fact, many organizations often do not know what they actually know
because they fail to persuade their employees to share knowledge. When people leave the
organisation, their knowledge will walk out of the door with them. Therefore, encouraging
knowledge sharing is the only way to keep the knowledge sustaining and growing.
1.3 Difficulties in Knowledge Sharing
One of the main difficulties in knowledge sharing is that people are reluctant to share
what they know with others. There are many reasons for this unwillingness. First of all,
people might find that they have spent a lot of time, efforts and even money to obtain their
knowledge. As a result, they feel unreasonable and lack of interest to share it with someone
else. Another widely held opinion is that people think their possession of knowledge has
some value and can bring them some certain advantages and even power over those who do
not have that knowledge. They tend to think that once they share it with someone else and the
others capture that knowledge, they will not have the advantages any more. Finally, it seems
to be a nature of human that people often do not trust each other. As a result, they are often
reluctant to share their knowledge with someone they do not know very well.
In order to overcome this reluctance, we need to reward people for their contribution in
the knowledge sharing process. We need to make more incentives to encourage them. Some
people prefer certain kind of recognition for their efforts and we can do that to persuade them
to open the door of their knowledge treasure. Finally, we can enhance the communication
channel between people and provide them with a comfortable and friendly environment to
work and collaborate with other people. This is to tighten up their relationship and help them
feel more secure to share the knowledge with their friends whom they feel trustable.
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9. Chapter 2 - Literature Review
According to our research, there exist in the public domain similar systems but each of
them typically only serves for one or a few aspects that a knowledge seeker desires. There
were no single systems which can satisfy all the needs in general. K-Comm comes in and
tries to bridge the gaps between the existing systems as well as provide new features.
2.1 Yahoo and Google Answers
Yahoo and Google Answers are a few of the sites which provide the closest features to
our K-Comm system. Both allow users to post questions and answers as well as provide the
mechanism to rate and give comments to the questions and answers, report abuse of the
system (e.g. posts that violate the terms and conditions, illegal questions, etc.). Yahoo
Answers even allows users to star a question, a very similar feature to our “Mark as
interesting question” function. Yahoo Answers have a better organization of the questions
compared to Google Answers, where they not only classify questions and answers based on
categories but they also differentiate between resolved and open questions.
Our K-Comm system also provides similar functions. In addition, we also evaluate and
monitor the quality of the knowledge of the answerers and assist the users in identifying those
people who are more likely to have a better answer. We also support embedded materials
such as audio and video in the posts. Moreover, we provide other social networking features
such as friend relationship, blogs, forums, and so on.
2.2 Youtube
Youtube started from a video sharing website. People come here to share their
entertainment and knowledge. However, things that a person can share on Youtube are
limited to those which can be transformed into a video format. Although this is an advantage
to some extent because sometimes it helps the users illustrate the ideas better, there are a lot
more other types of information and knowledge that cannot be captured in video.
In K-Comm, we do not restrict users to any representation format of knowledge. People
have a choice to share either text only or video or audio contents. As a result, we can capture
a wider range of knowledge than what Youtube can support.
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10. 2.3. Social Networks
Below is the list of social networks that we have visited and analysed:
Friendster: http://www.friendster.com
Facebook: http://www.facebook.com
Twitter: http://www.twitter.com
MySpace: http://www.myspace.com
Most of the social network sites are focused on helping people keep in touch with their
friends and maintain the relationship between them. What people often share in social
networks are things that they do in their life and there is very little knowledge factor involved.
Our K-Comm system, on the contrary, focuses on the knowledge aspect. We are more
interested in the knowledge being shared among the system users. Although we also support
fundamental social networking features, those features are to facilitate and maintain a
comfortable and collaborative environment for the knowledge sharing process of the users.
2.4 Blogs and Forums
We have the similar features in K-Comm but we do not restrict ourselves to only blogs
and forums. In addition, while blogs and forums are often concerned about some certain areas
of interest, we are open to knowledge across different domains.
2.5 Knowledge Management Systems
Similar to blogs and forums, Knowledge Management Systems are often used in a
restricted environment such as a company or organisation where relevant knowledge is
limited to certain specific fields. In addition, Knowledge Management Systems are also often
lack of the social network features.
The table below summarises the differentiating points of K-Comm over other similar
technologies:
Differentiating Points
K-Comm can evaluate the quality and contribution of
Yahoo Answers / Google
the answerers based on their answering history and
Answers
community ratings. K-Comm also supports
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11. embedded materials like audio, video, etc.
We are more focused on knowledge sharing rather
Social Networks
than personal relationship between users
Blogs, Forums We have similar features but they are more
knowledge sharing focused and not limited to
those features only
Blogs and Forums typically pertain to a certain
area of interest while we are open to various
domains in K-Comm
We don’t restrict the knowledge to a specific domain.
Other Knowledge Management
Instead, we leverage users’ expertise across different
Systems
domains. In our K-Comm, each user is an expert and
has something to share
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12. Chapter 3 - System Overview
3.1 What is K-Comm
We name our system K-Comm which stands for Knowledge Community. As the name
suggests, K-Comm is a knowledge-based social network. It provides most functions of
modern social network while still keeps its focus on knowledge sharing intention. You can
access the system at http://www.k-comm.tk.
3.2 Features
3.2.1 Social Network Features
K-Comm has been equipped with most of the common features that a typical social
network site should support. You can write your own blog, join the discussions in the forums,
make friends with other users of the same interest, gather in groups to have a better
collaboration, maintain a good relationship with your friends in the network, and so on.
Altogether, these features help create a collaborative, interactive, and comfortable
environment for all the members to come and participate in the knowledge sharing process.
3.2.2 Knowledge-based Features
K-Comm is not another social network. The social network features in K-Comm only
acts as a fundamental environment to facilitate and motivate the users to exchange their
knowledge with other users in the network. In K-Comm, it is believed that every individual is
an expert and we try to utilise and maximise that potential in order to benefit all the members
of the network.
The utmost purpose that K-Comm aims to achieve is to provide the users with
knowledge-focused activities and features. The users can come to system to:
Seek for answers to their questions
Get linked to people who might have the answers to their questions
Share knowledge with other people
Collaborate with like-minded people
Overall, K-Comm attempts to become an expert directory constituted from every
individual who is an expert in a particular field.
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13. 3.3 System Components
Core Library
Q&A Display
User
Profiling
Widgets
Questions
& Answers Rating
K-Comm
System
Social
Networking Point
System
User
Interface Skill Level
System
Figure 1: K-Comm System Components
The dimmed boxes represent components which are either not
implemented by the author or provided by the open source platform
The K-Comm system consists of three main components: the User Profiling package,
Social Networking package and the Questions and Answers package. On top of that is the
user interface that controls the look and feel, the layout and the flow of the whole system.
3.3.1 The User Profiling Package
This package is responsible for capturing all the information which is related to the
users of the systems. Upon registration, the users will be asked a few sets of questions in
which they tell the system about their basic information (e.g. name, gender, contact number,
etc.); what are the fields and categories that they are interested in; their background and user
type. The User Profiling package will capture all of this information and make it ready to be
used by other components in the system.
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14. 3.3.2 The Questions and Answers Package
This package is our central point to manage all the knowledge being shared by the users
of the system. It is responsible for assisting the users in sharing their potential knowledge as
well as looking for the knowledge or information they need in the fastest time. To be precise,
it provides the users with the following functions:
a) Ask and answer questions
The Questions and Answers Package allows users to ask and answer questions. The
questions and answers are classified in predefined categories. The predefined categories are
managed and maintained by the system administrators and by default have covered most of
the common areas of interest that the system users are likely to have. However, the users can
also give suggestions for new categories which have not been included in the system and
those categories will be added after being approved by the system administrators.
Not only the questions are structured into different categories, users can also add tags
into the questions to describe the questions more specifically. The questions can be searched
afterwards by both of their contents and the tags attached.
The system provides support for rich content which consequently means that the users
can post audios, videos or any embedded widget in their questions and answers. This is a
differentiating point from other services such as Yahoo or Google Answers. Using this
feature, the posters can give a more lively illustration and thus will help the readers have a
better understanding about the questions and answers being posted.
This function is provided by the core library and Q&A display. The core library models
the structure of the questions and answers being stored in the database while the Q&A
display component is responsible for pulling out the information from the database and
displaying it to the front end users.
b) Evaluate questions and answers
In order to encourage members of the society to contribute to the knowledge sharing
process, the system provides its users with the ability to rate the questions and answers. It can
be considered as the incentives for the questioners and answerers. All of the questions and
answers can be rated by other users except for the person who posted those questions and
answers. Users can also leave their comments for both questions and answers as necessary.
8

15. Additionally, the person who asks a question can choose the best answer among the answers
posted.
The rating and comments from the users will help the system evaluate not only the
quality of the questions and answers but also the contributions and the level of knowledge of
other users. It then will be able to analyse and tell:
What are the hottest questions
What answers are more likely to have a better value over the others
Who are more likely to have the expertise and ability to give good answers
In the knowledge sharing and seeking process, not only the quantity of knowledge
stored is important but the quality of the knowledge captured is also very critical. So it is
necessary for the system to be able to evaluate the knowledge being exchanged. In addition,
the system administrators can also get involved in the process by monitoring and filtering the
questions and answers in order to maintain the set of finest and most valuable knowledge.
These tasks are managed and controlled by the three components: the rating system, the point
system and the skill level system. The rating system is in charge of evaluating the questions
and answers. The point system takes care of the contributions of each individual user in the
knowledge sharing process. Finally, the skill level system analyses the quality of questions
and answers by each user and then evaluate the skill levels that they potentially possess.
Altogether, the three components work to ensure a good quality of the knowledge being
exchanged throughout the system.
c) Organise questions and answers
Knowledge exchange is a two way process. It is desirable that people come to use the
system not only to share the knowledge that they possess but also to look for the information
or knowledge that they want to know. In a real life situation, the amount of knowledge being
exchanged is often very large. Therefore, the system is expected to have some kind of
mechanism to help the users organize the set of questions and answers in a neat manner as
well as find the information they need as fast as possible.
In K-Comm, there are many ways for the users to locate the questions or answers they
want.
9

16. The first way is to use the Search box. The users can enter some text into the Search
box as the search criteria and then the system will look for those questions or categories that
match the given search criteria. After that, a list of questions will be displayed in the Search
Results panel together with some brief information about the questions (such as title, category,
date and time, author and number of answers) so that the users can further filter which
question they would like to look into details. The method is illustrated as in the figure below.
Figure 2: Search box
Another way to look for the questions is to look at the Interesting and Latest tab in the
main page (after logging in). When the users register to the system, they will be asked what
the categories that they are interested in are. The system will capture this information and
automatically list all the questions in those categories in the Interesting tab. So when the users
log in to the system, they can have a glance at the questions that are posted in their areas of
interest. In a similar manner, the Latest tab will list all the questions which have been posted
recently. The illustration is as in the figure below
Figure 3: Interesting and Latest tabs
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17. In addition, they can always click on a tag or a category to go to the list of questions
that have the same tag attached or posted in that specific category.
Besides locating the questions, the users are also provided with a way to manage
different kinds of questions. For example, they can edit their own dashboard to display the
lists of recent questions, the questions that they have asked, the questions asked by their
friends, etc. These are called widgets and they can be customized, added or removed in the
dashboard of individual users.
Figure 4: Widgets
d) Other functionality
In addition to the knowledge-focused functions, the system also comes with all the
fundamental functions of a typical social networking system. For instance, the users also have
a blog and can manage their relationships with other friends in the network. They can also
gather into groups and create discussion forums.
In conclusion, the K-Comm system tries to facilitate the users with a good social
networking environment in order to encourage them to exchange their knowledge with other
users. The system also assists the users in locating the information they want as quickly as
possible and managing the questions in which they are interested in an easy and tidy manner.
3.3.3 The User Interface
The User Interface package controls the consistency of the look and feel of different
components throughout the system. We have made a lot of changes to the interface so that the
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18. system does not look like the default Elgg site. Moreover, it is important that we want to
confine to the convention of Web 2.0 in order to give the users a good impression and the
incentives to make use of the system. Some of the rules of thumb we try to follow when
designing the user interface are:
Keep everything simple, intuitive and user friendly
Achieve the effect “I can find what I want to find”
Make it easy to use and learn
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19. Chapter 4 - Implementation
In this chapter, we will first describe how we apply the open source framework to
correspond with the features that we want in the system. Then we will look into details the
implementation of each component in K-Comm.
The principles we apply in the implementation might give an impression that it is
simple and straight forward but the complexity lies on the integration part where we need to
stick to the guideline given by the Elgg framework.
4.1 Elgg Framework
4.1.1 What is Elgg
Elgg is a free and open source framework for social networks. It provides the necessary
functionality to allow you to run your own social networking site.
(http://docs.elgg.org/wiki/What_is_Elgg). It is developed in PHP language and can work with
MySQL database server. The version we are using is Elgg 1.1. The latest version now is Elgg
1.5 with a lot of changes in the core engine.
We choose Elgg as our development framework because of the following reasons:
It is free and open source. It also works with PHP and MySQL which is also
free and open source environment.
It provides fundamental functionality for a typical social networking site so that
we do not need to waste time and efforts building our system from scratch.
The framework can be extended using customized plug in
We choose PHP as our development environment instead of .NET or JSP not only
because it is free but also because the PHP platform is considered as faster than that of .NET
or JSP. There is also more variety of available frameworks written in PHP for us to choose
from compared to .NET and JSP.
4.1.2 Elgg Engine
In this section, we will discuss about the underlying structure of the Elgg engine. It is
necessary that we understand how the framework works so that we can continue to build our
system features on top of it. Part of the technical points being discussed in this section is
referenced from the documentation on Elgg website (http://docs.elgg.org/wiki/Main_Page).
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20. However, the online documentation is very general and more often than not, it is not
sufficient for our implementation. Hence, this section also includes findings and conclusions
with which the author has come up during the trial and error and implementation process.
In this discussion of the Elgg engine, we will also mention about the pros and cons that
such structure brings about to our implementation.
We will start by looking at the Elgg Data Model which is illustrated as in the figure
below:
Figure 5: Elgg Data Model
In Elgg, the basic or atomic unit of data is called an entity (or ElggEntity as it is
referred to in the PHP code). So every access to the database should go through this layer of
abstraction rather than directly making SQL queries to the database. It is important to follow
this convention in order to ensure the integrity of the data model. Although Elgg provides us
with a few utility functions to work with the entities, sometimes they are not flexible enough
to suit our needs. For instance, it is not possible to use the utility functions provided by the
Elgg core engine to retrieve a list of entities in a sorted order (based on some criteria). As a
result, we will need to alternatively retrieve the list of entities and do a manual sorting on the
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21. list. The task will get more complicated and inefficient when the criteria involve several
attributes or aggregate functions. Another way to get around this problem is to add an
overloading utility function to the Elgg core engine to provide the same effect by altering the
SQL query being called. This approach is necessary as far as the efficiency of the operation is
concerned. However, we will have some compatible issues when upgrading the platform to a
newer version. As a result, in our implementation, we only touch the Elgg core engine when
efficiency is important. Otherwise, we use the first approach, that is, to do extra manual work
to achieve the effect.
Every other object in the system inherits the ElggEntity class. Four specialized types of
such classes have already been made to provide extra properties and methods for handling
different types of data easily. They are:
ElggObject
Objects like blog posts, uploaded files and bookmarks
ElggUser
Each user in the system
ElggSite
Each site in a multiple site system within the same Elgg install
ElggGroup
Multi-user collaborative systems
In our K-Comm system, most of the time we only make use of the ElggObject and
ElggUser and leave the ElggSite and ElggGroup untouched.
Each of the four specialized entities listed above come with their own distinguish
properties, for example ElggObject has a title and description while ElggUser has a username
and password and so on. Nevertheless, besides those properties, they also share common
properties which are inherited from the ElggEntity class:
Globally Unique ID (GUID)
A unique ID to identify the object throughout the system
Owner GUID
The ID of the object to which the current object belongs
Site GUID
The site that the entity object belongs to
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22. Access ID
The access permission of the entity object
Subtype
An additional name to differentiate from other entity objects of the same type
In addition to the built-in properties provided, we can also add more information into
the entity object to describe it further by utilising the metadata and annotation attached to the
ElggEntity.
Both metadata and annotation can be used to extend and customize our entity objects.
However, what is not so clear from the Elgg documentation is the difference between these
two types of additional information and when we prefer using this to the other. Based on our
experience implementing the system, we have come to the following observations:
The metadata can be used to store simple information such as tags, attribute ids,
etc. Under the hood, metadata is treated as a tag, and therefore it is searchable
and in fact most appropriate for the information that involves search operation.
The annotation is often used to store more complicated information which adds
to the information provided by the entity. For example, ratings and comments
can be considered as annotation. You will prefer using annotation to metadata
when we want to make some aggregation calculations for the entity objects.
Elgg provides us with adequate functions to do such calculation on annotation.
4.1.2 Mapping from Elgg to K-Comm
In this section, we will discuss how we make use of the functions provided by Elgg to
implement the features of our K-Comm system. In other words, we are mapping from Elgg
available features to K-Comm features.
Besides utilising the default social networking features provided by Elgg, we also make
use of these standard features and add more knowledge-focused functions to them. For
example, on top of the “friend” and “friend of” relationship support, we also build a widget
called Friends’ Questions to help the users keep an update of their friends’ questions and
answers more easily.
Elgg allows us to extend the system by creating customised plug-in. We have used this
plug-in support to build a number of components in our system. For example, the Questions
16

23. and Answers package is implemented as a plug-in. The user interface also customises the
look and feels of the system through plug-in and hence can be easily changed, enabled or
disabled.
Additionally, we also make a heavy use of the Elgg Data Model to make our K-Comm
system more object oriented as well as more portable and compatible. We use the metadata to
store the tags of the questions and annotations to keep track of users’ contributions and their
knowledge value estimation.
Finally, we use the widget model of Elgg to provide a handy tool for the users to
manage and organise their knowledge in the sharing process.
4.2 Core Library
Although Elgg has an abstraction layer in its data model to prevent direct access to the
database layer, we still find that it is necessary to have a higher abstraction level so that when
we move the system from the current platform to another platform in the future, we do not
need to make modifications to the business logic. As a result, we introduce a wrapper for the
Elgg entity objects and since Elgg has already followed the object oriented model to some
extent, we also use this approach in our implementation.
All the wrapper class we introduce will extend the ElggEntity base class. Most of the
time they utilise the properties title and description inherited from the ElggEntity class but
they also add on additional information where necessary.
Additional
Relationship
Wrapper
information
ElggEntity between
and utility Class
objects
functions
Figure 6: Wrapper Class Equation
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24. 4.2.1 Question Class
The Question class represents a question in the system. It utilises the standard
properties title and description of the ElggEntity object to store the title and the content of the
question. In addition, it also stores a list of tags that the users attach to the question in an
array and then put it in the metadata together with the entity. In a similar manner, the
category id and the count of page view information is also stored using the metadata.
The relationship between the Question class and the Category class is many to one.
Each question can belong to only one category (while one category can content many
questions). The Question class keeps a reference to the Category class by category id. So
given a Question entity object, we always know immediately which category it belongs to.
On the other hand, the relationship between the Question class and the Answer class is
one to many. Each question can have many answers. However one answer can only belong to
one question. We do not maintain a reference pointing from the Question class to the Answer
class. However, we have defined utility functions to retrieve the list of all answers that belong
to a particular question.
In addition to the metadata, each question is also attached with a Score object when it is
created. This is to recognise the contribution of a person when he or she asks a question by
rewarding them with some activity contribution points.
4.2.2 Category Class
The relationship between the Category class and the Question class has been described
in the section above. The similar relationship applies to the Answer class, too. Since the
Category class does not maintain a reference to Question and Answer class, we also define
utility functions to retrieve the list of all the answers or questions in a particular category.
In K-Comm, our category supports multi-level categories. That means we can have
nested categories ranging from general to specific. An example of the hierarchy can be found
below:
18

25. MySQL
Computer
Engineering
MS SQL
Computer Relational
Security Database
Oracle
Object
Database
Database
Computers &
DB2
IT
Flat Database
Java
Programming C#
.NET
Singapore
South East
Vietnam
Asia
...
Asia
Japan
Europe
East Asia
Korea
Travel America
Australia
Africa
Figure 7: Multi-level Hierarchy
To achieve this multi-level category support, we keep a parent id which is a reference
pointing from the current Category entity object to its parent category. The top level category
entities will have a parent id of -1. We can also retrieve a list of children category from the
current category by retrieving all the category entities that have the parent id equals to the id
of the current category.
4.2.3 Answer Class
The implementation of the Answer class is very similar to the Question class described
above.
19

26. 4.2.4 Integration
After we have our wrapper class for all the entity objects that we want, we will need to
integrate it into the Elgg framework.
First of all, we need to register the sub type (user defined type) of our classes to the
system when the Questions and Answers plug-in are loaded. This is to tell the system that we
have defined a new type of entity object and let the system know the location in which it can
find the definition of our classes. This registration is important because if we do not follow
this guideline, then whenever we try to retrieve an entity, say a question or answer, Elgg will
return an instance of the Elgg object instead of the wrapper class that we have defined. If that
happens, we will encounter problems which relate to the relationship between the classes. For
example, we will not be able to get the answer that belongs to a particular question.
After that, we need to register all the actions that relate to the sub types we have created.
Examples of the actions are creating a new question, deleting a question, editing a question,
etc.
Finally, we need to add the list of categories to the menu so that the users can easily
navigate through.
4.3 Widgets
Widgets are an integral part of the user experience with Elgg. Using Elgg's powerful
widget API, it is possible to provide access to both internal and external content, through
widgets, on a user’s dashboard or profile. Widgets can be available for both the profile and
dashboard, or they can be exclusive to either or. (http://docs.elgg.org/wiki/Plugins/Widgets)
Following are some of the widgets provided in K-Comm
Recent Questions
My Questions
Friends’ Questions
Related Questions
For each of the widget, we need to create a view and an edit page. The view page is
responsible for pulling out the information from the database and displaying it to the users
while the edit page is used to modify some settings for the widget.
20

27. 4.4 User Interface
The user interface of an Elgg system can be customized using theme. A theme is built
as a plug-in so that it can be easily distributed, customized, enabled or disabled.
We make use of the jQuery 1 JavaScript Framework to achieve cool effects for our
system. For example, a tool tip will appear when you move your mouse over certain items
and it will display the description of that item. Another example is the modal dialog which
appears when you click on the Log In link and allows you to enter your credentials and then
let you log in to the system.
The User Interface package must override the standard header of Elgg in order to inject
additional JavaScript such as jQuery. This sounds like a simple way to do things but in fact, it
is unsafe because when you upgrade to a newer version of Elgg, the default header might
change and you will need to manually update it in your customised header. Currently there is
no work-around for this because this is the desired way of how Elgg framework works.
The package also provides two layouts for other components of the system to use. One
layout is used when the users have not logged in to the system and the other is used when the
users have logged in. We also modularised the package in order to make it easy to change the
layout, the CSS style sheet and JavaScript in the future when necessary.
4.5 Skill Level System
Imagine that you are a user coming to the K-Comm system to look for some
information that you want, for example you want to find out some good car brand to buy.
After searching the system, you believe that nobody has asked some similar questions. So
you start to post your own question in the Home Asset category. One day later you come
back to the system to check for answers to your question and find that there are a lot of
people throwing the answers to your question. You are happy about it but very soon later, you
start to feel confused because you don’t know whose advice you should take since you are
new in this category and know very little about cars.
As a result, we would like to come up with an approach to assist the users in this
situation. In other words, we want to establish a mechanism to analyse and estimate the level
of potential knowledge that each user probably possesses. After that, we will try to help other
1
jQuery is a fast and concise JavaScript Library that simplifies HTML document traversing, event
handling, animating, and Ajax interactions for rapid web development. (http://jquery.com)
21

28. users of the system to identify the people with a high potential of possessing a good level of
knowledge in some particular categories.
We will implement this mechanism in our Skill Level System. The idea is to monitor
the activities that a user takes part in when they are using the system. Based on the result of
activities, we can have estimation about how good they are at some specific categories. A
person can be good at these categories while not so good at the others. So we need to capture
this information at the category level.
For example, a person has raised a lot of good questions in the Car category (we
consider the questions to be good based on the evaluation of other users through their rating).
He or she also has given a lot of answers which are rated as good by other users. Some of his
or her answers are even selected as the best answer by some questioner. Accordingly, we
have some good reasons to tell that this person might have a very good knowledge about cars.
John Mary
25 25
20 20
Best Answers Best Answers
15 15
Answer Answer
Count Count
10 10
Question Question
Count Count
5 5
Answer Answer
Rating Rating
0 0
Question Question
Rating Rating
If our analysis for the activities that John and Mary have participated in is as in the
chart above, we might want to come to the estimation that John is likely better than Mary in
the area of computers while Mary knows better about cars than John does.
22

29. Skill Level for John and Mary
John
Car
Computer
Travel
Mary
0 1 2 3 4 5 6 7 8 9
After we capture the skill level for John and Mary, we also need to make that
information available for other users. So we show the skill level of John and Mary in the
questions and answers that they have posted. As a result, when a user sees answers posted by
John in the Computer category, they will know that these answers are probably more accurate
and trustable (since John has a good expertise in this area). Similarly, in the Car category,
Mary’s answers are more likely to have a higher weight.
4.5.1 Requirements
Now the problem that we need to solve is to construct a function from the Cartesian
product of the sets of Category and User to the set of real number from 0 to 10:
In addition, the function needs to be in terms of:
The rating of questions and answers from the user in the particular category
The total number of questions and answers from the user in the particular
category
The number of answers from the user in the particular category which have been
selected as the best answer
While constructing the function and the Skill Level System, besides accuracy, we
also need to take into account the following practical requirements:
23

30. If a person has some knowledge in a particular category, he or she should be
considered to have some knowledge in the parent category, too. For example, in
a user’s perspective, if I know about Java, it also means that I know about
Programming too.
If a person has not logged in to the system for some time, when he logs in the
next time, his skill level should remain the same and not decline.
4.5.2 Unsuccessful Attempts
At first, we decided that initially, every user has a starting skill level for a particular
category. After that, whenever they take part in an activity (ask a question, answer a question,
answers selected as the best answer), then we will calculate a new skill level and that new
value will account for certain amount of the overall skill level that they have pertained so far.
The formula that we came up with is as follows:
The good thing about this attempt is that by putting some weight to the Old Point and
New Estimated Point, we prevent the final skill level from increasing unboundedly.
However, this approach is not acceptable because it introduces a problem in which the skill
level of a user will remain unchanged or even decrease no matter how hard he or she try to
participate in the activities. This is because after some time, the current value of skill level is
too high compared to the maximum point that people can earn by participating in an activity.
You can argue that we can adjust the weight of the New Estimated Point. However, if you
give too much weight for the New Estimated Point, then it becomes very easy to improve
someone’s skill level. The consequence is everyone will eventually get roughly the same skill
level and the system will be unable to distinguish between good and not so good knowledge
sharer.
24

31. We then modify the solution. Instead of keeping an old value for the skill level, we
leave it increasing. That is:
However, to keep it unbounded, we normalise it by compared it to the maximum skill
level that has been achieved in the system. The skill level now give you an idea about how
good you are compared to others in the system instead of indicating an absolute value about
your knowledge expertise.
Nevertheless, this approach is not applicable in practice, either. The problem is if the
user does not log in to the system for some time while the rest users continue to participate in
the system regularly, that user’s skill level will be outdated (and thus become very low)
compared to others. This does not make sense because your knowledge can not decrease just
because of your inactivity. The level of activity of a user has already been captured by the
Point System. The Skill Level System should only focus on the quality of the knowledge
being shared by a user in a particular category.
4.5.3 Our Approach
After the failure of previous attempts, we came up with a new working approach. We
try to analyse the skill level of the user only after his work (asking or answering) has been
evaluated by other users. So the user’s skill level will not drop over time but it will only drop
if other users rate his questions or answers as bad.
The calculation of the skill level is as follows. If a user has asked questions in a
particular category but none of his questions have been rated, then he will get 0.5 for the
question part. Otherwise, the average of the rating of his questions will be used for his
question part. Similarly, if he has posted answers in the category but none of his answers
have been rated, then he will get 0.5 for the answer part. Otherwise, he will get the average of
the rating of his answers. Finally, the question part will account for 40% and the answer part
will account for 60% of the Q&A points. The reason for the ratio 4 : 6 is that when a person
is able to answer some questions in a category, it is more likely that he knows about the
category well than in the case he is asking a question in that category. In addition, we also
25

32. take into account (with a light weight) the number of questions and answers that the user has
posted and the number of answers which have been selected as the best answers. The full
calculation formula is shown below:
If the category has sub categories, then the skill level will be the balance of the category
itself and its children:
In order to avoid calculation overhead, we will not carry out the calculation every time
we want to display the skill level value. Instead, we will store the final value and display it
when necessary. We only make an update of the constituent components of the function
(question and answer count, average rating, number of best answers) and calculate again
when the user participates in a new activity.
26

33. Chapter 5 - Conclusion
5.1 Summary
In this project, we have specified and formalised the specifications that the Knowledge
Community system should have. We then studied the existing similar systems that are
available and the interesting features that we might want to include in K-Comm. We also
designed the basic structure for our system and identify the fundamental constituent
components. After that, we analysed the open source Elgg framework and found out how to
make use of it to implement our system. Finally, we started to build the essential components
of K-Comm.
5.2 Difficulties and Limitations
Although the components of the system that we have implemented are those essential
and fundamental components and there is still room for improvement, we at least have
formed a concrete shape of the system which we want to build. We also constructed the basic
foundation for the system which then can be easily extended and customised on top of it.
From now on, other people can continue the work based on what we have so far.
The nature of this project is more on implementation. In fact, the difficulties are on the
implementation part. Although Elgg framework is available and ready for use, integration
work is not easy to be done because they are lack of an adequate documentation.
Understanding how the framework works is not trivial and looking for the current methods to
call is sometimes difficult without the help of documentation. On top of that, although PHP is
a fast environment, it is not a very friendly environment for development. In particular, we
find it very hard to do debugging in PHP environment, especially with a big system like K-
Comm. More often than not, it takes a couple of hours to discover a small mistake.
Putting this together with the time constraints, the result of the project is limited to
building the basic platform for the K-Comm system. This opens opportunity for more
research and implementation work to be done in the future.
5.3 Recommendations for Further Work
In the future, we can do research on how to analyse the questions and answers being
posted by using natural language processing techniques. This will help in automatic analysing
27

34. and understanding the knowledge being shared in the system. We can also study the
relationship between the tags attached to different questions. Furthermore, we can come up
with different ways to represent and organise the questions and answers.
28

35. References
Agarwal, N.K. and Poo, D.C.C. (2006). Capturing tacit knowledge across different domains:
Knowledge Community (K-Comm).
Bonnie Montano (2004). Innovations of knowledge management. IRM Press (March 22,
2005).
http://www.techcrunch.com/wp-content/wlsn_comparison_chart.html
http://www.sim.edu.sg/mbs/pub/mag/mbs_pub_mag_list.cfm?ID=1877&mnuid=92
http://www.aijc.com.ph/KM_site/docs/Annex%203.pdf
http://www.aijc.com.ph/KM_site/docs/Annex%203.pdf
http://www.150jahre.ethz.ch/program/ethvisionen/tag_der_universitaeten/programm/kleiber.p
df
http://net.educause.edu/ir/library/pdf/erm0350.pdf
http://www.tfhrc.gov/pubrds/novdec99/km.htm
http://www.gurteen.com/gurteen/gurteen.nsf/id/ksculture
http://lnweb90.worldbank.org/oed/oeddoclib.nsf/DocUNIDViewForJavaSearch/D9E389E741
4BE9DE85256DC600572CA0/$file/knowledge_eval_literature_review.pdf
29

36. Appendix
Functions provided for metadata
Source: http://docs.elgg.org/wiki/Engine/DataModel/Metadata
function create_metadata(
$entity_guid, // The GUID of the parent entity
$name, // The name of the metadata (eg 'tags')
$value, // The metadata value
$value_type, // Currently either 'string' or 'int'
$owner_guid, // The owner of the metadata
$access_id = 0, // The access restriction
$allow_multiple = false // Do we have more than one value?
)
function get_metadata_byname (
$entity_guid,
$meta_name
)
function get_metadata_for_entity (
$entity_guid
)
Functions provided for annotations
Source: http://docs.elgg.org/wiki/Engine/DataModel/Annotations
function annotate(
$name, // The name of the annotation type (eg 'comment')
$value, // The value of the annotation
$access_id = 0, // The access level of the annotation
$owner_id = 0, // The annotation owner, defaults to current
user
30

37. $vartype = quot;quot; // 'string' or 'integer'
)
$annotations = $entity->getAnnotations(
$name, // The type of annotation
$limit, // The number to return
$offset, // Any indexing offset
$order, // 'asc' or 'desc' (default 'asc')
);
function elgg_view_comments(ElggEntity $entity)
31