- Email: [email protected]
Using hypertext for computer based learning
ComputersEduc. Vol. 17, No. 3, PP. 173-179, 1991 Printed in Great Britain. All rights reserved
USING HYPERTEXT
0360-1315/91 %3.00+0.00 Copyright 0 1991 Pergamon Press plc
FOR COMPUTER ALAN
School
of Computer
Applications,
Dublin
BASED LEARNING
F. SMEATON City University,
Glasnevin,
Dublin
9, Ireland
(Received 6 May 1991; accepted 6 August 1991) Abstract-One of the many potentially useful applications for hypertext to emerge in recent years is in the area of computer-aided learning. This paper describes the results of an experiment in which undergraduate students used a hypertext about database systems as part of their coursework. The hypertext was offered as a source of learning information in addition to recommended textbooks and lectures. Students were surveyed on when, and how, they used the hypertext, for what specific purposes and what types of searching they preferred. The results and analysis of this survey of actual hypertext usage is presented. Our conclusions confirm earlier published results that current hypertext products have obvious shortcomings and that hypertext in genera1 cannot replace conventional teaching but should be regarded as being complementary to it.
INTRODUCTION
The organisation of information in a hypertext system has found many applications [ 11. This paper looks at the application and uses of hypertext systems in learning. Users’ information needs can be satisfied by hypertext systems which support a range of activities from browsing to searching for specific information. These information needs could be satisfied by various hypertext organisations which are suited to these different information needs. In a simple hypertext network an author would create an information space which had no coherent structure whatsoever and which could be termed a purist’s hypertext. However, such a structure can present problems when navigated by users who can easily become lost as the topology of the hypertext is monotonous and lacks guiding features. On the other hand a highly structured hypertext would be almost an electronic version of the table of contents in which all information is located in a hierarchy. The links would be structural and not semantically-based though there may be links to definitions of terms, figures, tables and graphics. We can also have a combination of the above where a hierarchic table of contents exists in parallel with a set of semantic links. These are the most feasible of the many possible ways of organising nodes of information in a non-linear fashion which have to be managed by the hypertext author. The topologies are shown in Fig. 1. There seem to be 2 reasons for including elements of hierarchies in hypertext design. The first is that many hypertexts have their origins in existing paper documents and there is much interest in automatically turning the huge amount of text available in machine-readable form, much of it with hierarchical organisation, into hypertext [2]. The second reason for using hierarchical structure in hypertext is to support navigation. Many solutions to the problem of navigation have been proposed[3], some of which exploit human spatial processing abilities by representing the hypertext in a 2 or 3 dimensional space with maps, landmarks, compasses, etc., while other methods employ the navigation tools used in traditional printed media like bookmarks, annotations and thumbtabs. A hierarchical organisation of a hypertext provides convenient navigation for users who can use the structure to navigate, thus freeing them to concentrate more on what is being presented instead of worrying about where to go next. The disadvantage of a hypertext system constructed as a hierarchy is that it could be viewed as an implementation of a conventional book using the computer, which allows users to follow cross-references in text quite rapidly. The current generation of hypertext systems would appear less effective than books for retrieving information when a user wants to find specific information[4]. Only recently has there been serious effort investigating whether hypertext could support the learning process or not [5]. One of the obvious advantages of using simple hypertext for learning is that it allows much freedom for users to determine what they see but it cannot enforce testing or evaluation of learning as conventional CBT would do. We have investigated how users cope with this relaxation of discipline and how they then use the hypertext when the goal is learning. CAE11,‘3--A
173
ALAN F.&EATON
174
(c
Fig.
I. (a) Network hypertext
organisation; (b) Strict hierarchical of hierarchical and network hypertext
EXPERIMENTAL
hypertext organisation; organisation.
(c) combination
DESIGN
The hypertext we developed as courseware for our experimental evaluation was done using HyperTies version 2.35[6] running on an IBM PS/2 with colour screen and EGA graphics. This system has two separate components, a browser tool which allows reading of a hypertext and an authoring tool which allows creation and reading of a hypertext. Individual nodes may include text and/or graphics and links are uni-directional and anchored within strings in the text. Graphics were created using PC-Paint and the equipment used by students were mostly 386-based IBM PC compatables or PS/2s. The hypertext we created covers most of the material that would be included in a typical 40-lecture introductory course in databases to third year undergraduate students at a third level college. This course is followed by another 15 lectures of advanced database topics in the final year of the degree. Apart from an overview of databases, the course covers SQL, query optimisation,
Hypertext
for learning
175
the relational and other models of data, normalisation, the system catalogue and other topics typically appearing in a standard database textbook [7]. The hypertext was prepared over a period of 3 months and the hypertext and the HyperTies browser were installed on a PC file server with access using a Novell network of PCs. Students were also issued with their own copy of the hypertext and browser to use on other machines inside and outside the University if they so wished. The hypertext on data bases consisted of 462 nodes, 23 of which include some graphics. There were a total of 234 kbytes of text in the nodes, with an average of 74 words per node. There was quite a variance in the sizes of the nodes with the largest consisting of 213 words and the smallest being of only 15 words (a node giving an example of an SQL SELECT statement). These nodes are small in size because we wanted every node to appear on a single screen. HyperTies does not have scrollbars and the way it handles the presentation of a node which is more than a single screen is that it allows toggling from page to page. This further increases the work that the user must do in that as well as orientation and navigation and assimilation of information, users must also keep track of what screen within a given node is currently being displayed. By making all nodes fit onto one screen we eliminated this task. In addition to the nodes, our database hypertext contains a total of 1398 one-way information links. Of these, 746 are involved in “two-way” links, i.e. 373 instances of A linking to B and B linking to A, and 652 nodes were genuine one-way links. Each node has an average of 3.03 links coming from (and going into) it. However, this simple average belies a great variety in the distribution of information links with some nodes acting as hubs or highlighting connected landmarks in the hyperspace, and others acting as dead ends. Six of our nodes had more than 10 information links coming from them, while 133 nodes have only one link coming from them. Like almost all of the current generation of hypertext authoring tools, the HyperTies system offers very little in the way of assistance to the hypertext author apart from maintaining a list of “dangling” information links whose destination node has not been decided yet. We have already discussed navigation and orientation problems for browsers, but these tasks are even more difficult for hypertext authors. The authoring strategy we adopted for our database hypertext was to take a database topic, build a hypertext around that topic and then integrate all the individual topics together. Thus our hyperspace has an underlying topology which consists of several hubs or foci presenting an overview of a topic with information links to nodes describing details radiating outwords and among themselves, eventually, through a series of nodes, connecting into another topic and its focus or overview node. At a local microscopic level our hypertext looks like a true network hypertext, but from a more abstract macroscopic level we prefer to regard it as a collection of landmark or overview nodes in a network hypertext which we believe will make it convenient for navigation. An indication of the topology of our hypertext is given in Fig. 2. With our hyperspace organisation and using the HyperTies browser tool, there are a number of different types of navigation and browsing which are possible given a user’s information need. The first of these is to use HyperTies to perform a search for a given string occurrence in the texts of the nodes. This string can be a boolean combination of pairs of ANDed keywords. HyperTies determines the set of nodes in the hypertext which contain the specified string. The user can then Preface
Fig. 2. Topology
of air database
node
hypertext.
176
ALAN F.SMEATON Table
I. Total
number sessions
Table 2. Duration of hypertext student
of hypertext
Number of times used
Number of users
I
6
2 3 4 5 &IO +10
Total duration (h1
Number of “%FS I5 7 5 6 I7
CLI I-2 2-3 34 f4
8 9 8 4 IO 5
use per
choose one of these hits from which to commence browsing. A variation or refinement of this method of browsing is to return to the output of the string search during the session to ensure all nodes containing the given string have been kited by the user. Each node seen during a HyperTies session has an asterisk beside its title indicating that it has been viewed already, although the enforcement of the discipline of visiting all such nodes is left to the user. HyperTies builds a history list of all nodes visited during a session and users can use this for navigation as well as for traversal. Users can also call up their history list and return to a previously viewed node without having to backtrack to the node currently displayed. This utility eases the problem of users having multiple digressions or information needs. Another way of browsing our hypertext is to follow structural links. HyperTies present a PREFACE node as the first screen of information every time a session is commenced. In our case the preface node contains a text overview of the hypertext contents with information links to the overview nodes. The user can follow the information links to overview nodes, the authored content-indicating hierarchy of nodes to support navigation and traversal. In the final browsing option, a user can view an alphabetical listing of node titles referred to as the index. In summary, the browsing options in our system are: (1) (2) (3) (4) (5)
String search to find a single start node and browse String search and explore all the identified nodes Use history list of nodes visited Follow PREFACE to move to topic overview nodes Use index of node titles
and browse
from there
Options 1, 3 and 5 could be classified as unsupervised browsing, option 4 is structured browsing and option 2 is somewhere in between. The hypertext database was used by students in the third year undergraduate courses in Computer Applications and in Applied Mathematical Sciences and students were surveyed in their use of the hypertext system. Fifty students correctly completed and returned the survey, 27 male and 23 female subjects. Those surveys which we did not use were either incomplete or had multiple answers to a single-choice question. In addition, one of the questions asked if the user knew how to sort the names of nodes alphabetically, which is not possible within HyperTies. Those surveys that responded “yes” to this question were also discarded. The results of the survey are detailed in the following section.
Table 3. Where the hypertext
was used Number of users
Used the hypertext Used the hypertext
alone in company
Used the PC serve1 Used another PC in college Used a PC outside college Stage of use of the hypertext: regularly, throughout course periodically, throughout course end of lectures, for a subject overview just before the exam, for revision
37 I3 27 5 18
Table 4. Preferred
methods
of commencmg
Number of users
I 14 I7 39
scss~ons
Use overview node, browse from there Perform string search, browse from result Use index of node titles, browse from there
I5 19 16
Hypertext for learning Table
5. Average path length backtracking
Browse path length (No. of nodes)
177
before
Number of “SeIX
I
I
2 3 4 5 6 7 8 9
2 IO 19 II 3 3 0 I
Table 6. Users rating of the ease of use of HyperTies Easy Scale value Number of users
RESULTS
ON
HYPERTEXT
123456789 25 15 6 2
Impossible 0
2
0
0
0
USAGE
The survey contained 14 questions relevant to this study, which can be grouped under 3 headings, namely when the hypertext was used, how the hypertext was used and a summary of the users’ opinions on the hypertext. When the hypertext
was used
Tables 1 and 2 summarise the frequency and the duration of use of the hypertext, during the academic year. Some students used the hypertext extensively (these tended to be the ones who made most comments in the survey returns) with 30% having 6 or more sessions and 34% claiming to have used it for 4 h or more. On the other hand 12% of the students used the hypertext only once, and 30% say they used it for < 1 h in total. Table 3 gives a breakdown of where the hypertext was used and from that we can see that the majority used it alone, although there was some group work as well. The most interesting data are for the stage of the course at which the hypertext was used. The figures paint a picture of a diverse groups of students, some keenly interested in new software and using it throughout the course while others have their first use of it just before the examination. From individual comments on the survey forms some of the most common statements were that they “would use it more frequently next time, throughout the course rather than just for revision”, and that they “didn’t realise what it could be used for until it was too close to the exam”. Users also reported their sessions as being of 3&45 min maximum, before they claimed that disorientation started to become a problem. How was the hypertext
used
Table 4 summarises the mode of use of the hypertext when a user was commencing a session. Students chose almost equally between following the PREFACE and overview nodes, performing a string search, or using the listing of the node names or titles as a start for a session. Once the users had started browsing the hypertext, their average path length before backtracking is given in Table 5. The majority of users had an average path length of 3, 4 or 5 nodes, before they started to backtrack. Users were asked to answer 7 specific questions from the hypertext. Almost all answers to this and other questions indicated that the answer was obtained by using string searches as opposed to following overview nodes. So for specific information needs users almost always use an unstructured search. Related to the use of string searching in browsing we also asked users whether they would ensure that they visited all nodes in the output set from a string search, in order to guarantee that they Table I. Users requirement of the content of the hypertext Adequate Needs more example nodes Needs less example nodes Needs more overview nodes Needs less overview nodes
5 43 2 10 2
ALAN F. SMEATON
178
had covered all information in the hypertext pertaining to a given topic. In answering this question 31 said they would visit all nodes, 11 said they would not and 8 said they did not use the string search facility at all when browsing. What did users think
qf the hypertext?
Finally, we asked users’ opinions of the hypertext. Forty-eight of the 50 subjects said that they would lend it to a friend in another university who was following a similar course, and 46 said that the coverage should be extended to encompass other database material they would study in their final year at college. Forty-three subjects replied that we should definitely distribute the hypertext to students next year, only one was positively against this. HyperTies, and the way we configured it made the system simple to use (Table 6). Other responses were divided into comments on HyperTies and comments on the content. There were many suggestions for improvement to the HyperTies system. The most commonly occurring comment on HyperTies was for the system to provide a mechanism for personalised note-taking or highlighting of the hypertext. Users wanted to annotate the hypertext with their own material as they make margin scribbles and use highlight markers with printed material. Users wanted to create their own links and nodes, but doing this in HyperTies is non-trivial as authoring is a separate process. They would also like navigation tools like bookmarks, despite orientation not being recognised as a problem. These results are consistent with those reported by Leggett et al. [8]. On the content of the hypertext, subjects answered a multiple-choice question. (Table 7). The overwhelming requirement is for more example nodes to illustrate concepts like “database schema normalisation” and the workings of certain SQL statements. This may be due in part to the nature of the material being presented. These topics are ones which are conceptually difficult and in lectures and books are heavily illustrated by worked examples. DISCUSSION Experimental results relevant to our work are reported by Stanton and Stammers[9] who evaluated student performances with structured and exploratory or unsupervised learning environments, where the structured material was CBT and the exploratory was hypertext. That experiment was inconclusive. We offered both structured and unstructured searching within hypertext in the form of overview nodes and string searching respectively. Our results show that students use a mixture of both, with a majority of unstructured searching. When asked for specific information from the hypertext, users almost always use unstructured methods. In our environment users tended not to browse too far before backtracking, usually 3,4 or 5 nodes. This could be because the users would have read enough on the current topic and wanted to move onto something else, or it could be attributed to disorientation caused by the poor support for navigation of the browser tool. Many solutions have been proposed to counter disorientation including bookmarks, compasses, and graphical browsers[3]. These proposals can be grouped into two classes; those that reproduce traditional orientation cues from text evolved over centuries and those that exploit human spatial processing ability. With the former, Kerr[lO] argues that traditional navigation methods may not be appropriate in hypertext, although in our survey users indicated that they wanted bookmarks and text highlighters. With the non-traditional type of navigation, the user still has a problem as browser maps etc. are only navigation aids. Reynolds and Dansereau[l I] have compared A hypermap is a knowledge structure with a hypermaps and hypertexts for learning. node-link-node basis but unlike hypertexts the links are dynamically implemented and the basic nodes can themselves be node-link-node structures. Their experimental results comparing hypermaps and hypertexts found no significant differences in recall between the two but users were more satisfied with hypermaps than hypertexts. Another factor holding up the spread of hypertext is the hypertext authoring process. As mentioned earlier, HyperTies was no help to overall organisation and we need browsers not just an apprentice for suggesting links but which relates the hypertext to an overall plan. Anybody who has authored a hypertext of any size should agree with this. If hypertext usage is to increase, the development of more helpful authoring tools is imperative.
Hypertext
for learning
179
We believe current hypertext tools cannot replace conventional CBT as they are too unstructured in the order of presentation of material and burden the user with too many distractions from actually reading and assimilating the material being presented. In related work, we are developing tools to help users construct a plan or a route through the hypertext thus creating a richer learning environment [12]. In CBT applications the user’s information need is dominated by having to learn the content of the material and the user should be free from any extra cognitive overheads. The results of our experiments reported in this paper were for using hypertext as adjunct courseware to be used in tandem with lectures and textbooks. With such an application there may be a role for a hypertext presentation of material as a reader may already have an overall grasp or picture of the material and may be seeking clarification or specific information or perhaps to explore the relationships between concepts. Indeed most of our subjects in this survey reported that they used the hypertext for revision, just before the exam, when seeking information on specific topics. REFERENCES 1. Nielsen J., Hypertext and Hypermedia. Academic Press, London (1990) 2. Bernstein M., An apprentice that discovers hypertext links. In Hypertext: Concepts Systems and Applications (Edited by Rizk A., Streitz N. and Andre J.), pp. 212-223. Cambridge University Press, Cambridge (1990). N., Context and orientation in hypermedia networks. ACM Trans. Inform. Sysr. 7, 58-84 3. Utting K. and Yankelovich (1989). retrieval and hypertext: competing technologies or complimentary access methods. School 4. Smeaton A. F., Information of Computer Applications. Working paper, CA-0191, Dublin City University (1991). 5. Jonassen D. H. and Mandl H. (Eds), Designing Hypermedia for Learning. Springer, Berlin (1990). 6. HyperTies Author’s Guide, Cognefics Corporation, Princeton, N.J., March (1989). Redwood City, Calif. (1989). 7. Elmasri R. and Navathe S. B., Fundumenfuls of Database Systems. Cummings, In Designing Hypermedia for Learning (Edited 8. Leggett J. J., Schnase J. L. and Kacmar C. J., hypertext for-learning. by Jonassen D. H. and Mandl H.), PP. 27-38. Springer. Berlin (1990). 9. Stanton N. A. and Stammers R. B.‘, Acomparison of structured and unstructured navigation through a CBT package. Computers Educ. 15, 159-163 (1990). cues vs mental models. Inform. 10. Kerr S. T., Wayfinding in an electronic database: the relative importance of navigational Process. Mgmr 26, 511-523 (1990). 11. Reynolds S. B. and Dansereau D. F., The knowledge hypermap: an alternative to hypertext. Computers Educ. 14, 409416 (1990). In AI and Cognitive Science 91 (Edited by 12. Smeaton A. F. and Guinan C., Intelligent searching through hypertexts. Sorenson H.). Springer (1992).
USING HYPERTEXT
0360-1315/91 %3.00+0.00 Copyright 0 1991 Pergamon Press plc
FOR COMPUTER ALAN
School
of Computer
Applications,
Dublin
BASED LEARNING
F. SMEATON City University,
Glasnevin,
Dublin
9, Ireland
(Received 6 May 1991; accepted 6 August 1991) Abstract-One of the many potentially useful applications for hypertext to emerge in recent years is in the area of computer-aided learning. This paper describes the results of an experiment in which undergraduate students used a hypertext about database systems as part of their coursework. The hypertext was offered as a source of learning information in addition to recommended textbooks and lectures. Students were surveyed on when, and how, they used the hypertext, for what specific purposes and what types of searching they preferred. The results and analysis of this survey of actual hypertext usage is presented. Our conclusions confirm earlier published results that current hypertext products have obvious shortcomings and that hypertext in genera1 cannot replace conventional teaching but should be regarded as being complementary to it.
INTRODUCTION
The organisation of information in a hypertext system has found many applications [ 11. This paper looks at the application and uses of hypertext systems in learning. Users’ information needs can be satisfied by hypertext systems which support a range of activities from browsing to searching for specific information. These information needs could be satisfied by various hypertext organisations which are suited to these different information needs. In a simple hypertext network an author would create an information space which had no coherent structure whatsoever and which could be termed a purist’s hypertext. However, such a structure can present problems when navigated by users who can easily become lost as the topology of the hypertext is monotonous and lacks guiding features. On the other hand a highly structured hypertext would be almost an electronic version of the table of contents in which all information is located in a hierarchy. The links would be structural and not semantically-based though there may be links to definitions of terms, figures, tables and graphics. We can also have a combination of the above where a hierarchic table of contents exists in parallel with a set of semantic links. These are the most feasible of the many possible ways of organising nodes of information in a non-linear fashion which have to be managed by the hypertext author. The topologies are shown in Fig. 1. There seem to be 2 reasons for including elements of hierarchies in hypertext design. The first is that many hypertexts have their origins in existing paper documents and there is much interest in automatically turning the huge amount of text available in machine-readable form, much of it with hierarchical organisation, into hypertext [2]. The second reason for using hierarchical structure in hypertext is to support navigation. Many solutions to the problem of navigation have been proposed[3], some of which exploit human spatial processing abilities by representing the hypertext in a 2 or 3 dimensional space with maps, landmarks, compasses, etc., while other methods employ the navigation tools used in traditional printed media like bookmarks, annotations and thumbtabs. A hierarchical organisation of a hypertext provides convenient navigation for users who can use the structure to navigate, thus freeing them to concentrate more on what is being presented instead of worrying about where to go next. The disadvantage of a hypertext system constructed as a hierarchy is that it could be viewed as an implementation of a conventional book using the computer, which allows users to follow cross-references in text quite rapidly. The current generation of hypertext systems would appear less effective than books for retrieving information when a user wants to find specific information[4]. Only recently has there been serious effort investigating whether hypertext could support the learning process or not [5]. One of the obvious advantages of using simple hypertext for learning is that it allows much freedom for users to determine what they see but it cannot enforce testing or evaluation of learning as conventional CBT would do. We have investigated how users cope with this relaxation of discipline and how they then use the hypertext when the goal is learning. CAE11,‘3--A
173
ALAN F.&EATON
174
(c
Fig.
I. (a) Network hypertext
organisation; (b) Strict hierarchical of hierarchical and network hypertext
EXPERIMENTAL
hypertext organisation; organisation.
(c) combination
DESIGN
The hypertext we developed as courseware for our experimental evaluation was done using HyperTies version 2.35[6] running on an IBM PS/2 with colour screen and EGA graphics. This system has two separate components, a browser tool which allows reading of a hypertext and an authoring tool which allows creation and reading of a hypertext. Individual nodes may include text and/or graphics and links are uni-directional and anchored within strings in the text. Graphics were created using PC-Paint and the equipment used by students were mostly 386-based IBM PC compatables or PS/2s. The hypertext we created covers most of the material that would be included in a typical 40-lecture introductory course in databases to third year undergraduate students at a third level college. This course is followed by another 15 lectures of advanced database topics in the final year of the degree. Apart from an overview of databases, the course covers SQL, query optimisation,
Hypertext
for learning
175
the relational and other models of data, normalisation, the system catalogue and other topics typically appearing in a standard database textbook [7]. The hypertext was prepared over a period of 3 months and the hypertext and the HyperTies browser were installed on a PC file server with access using a Novell network of PCs. Students were also issued with their own copy of the hypertext and browser to use on other machines inside and outside the University if they so wished. The hypertext on data bases consisted of 462 nodes, 23 of which include some graphics. There were a total of 234 kbytes of text in the nodes, with an average of 74 words per node. There was quite a variance in the sizes of the nodes with the largest consisting of 213 words and the smallest being of only 15 words (a node giving an example of an SQL SELECT statement). These nodes are small in size because we wanted every node to appear on a single screen. HyperTies does not have scrollbars and the way it handles the presentation of a node which is more than a single screen is that it allows toggling from page to page. This further increases the work that the user must do in that as well as orientation and navigation and assimilation of information, users must also keep track of what screen within a given node is currently being displayed. By making all nodes fit onto one screen we eliminated this task. In addition to the nodes, our database hypertext contains a total of 1398 one-way information links. Of these, 746 are involved in “two-way” links, i.e. 373 instances of A linking to B and B linking to A, and 652 nodes were genuine one-way links. Each node has an average of 3.03 links coming from (and going into) it. However, this simple average belies a great variety in the distribution of information links with some nodes acting as hubs or highlighting connected landmarks in the hyperspace, and others acting as dead ends. Six of our nodes had more than 10 information links coming from them, while 133 nodes have only one link coming from them. Like almost all of the current generation of hypertext authoring tools, the HyperTies system offers very little in the way of assistance to the hypertext author apart from maintaining a list of “dangling” information links whose destination node has not been decided yet. We have already discussed navigation and orientation problems for browsers, but these tasks are even more difficult for hypertext authors. The authoring strategy we adopted for our database hypertext was to take a database topic, build a hypertext around that topic and then integrate all the individual topics together. Thus our hyperspace has an underlying topology which consists of several hubs or foci presenting an overview of a topic with information links to nodes describing details radiating outwords and among themselves, eventually, through a series of nodes, connecting into another topic and its focus or overview node. At a local microscopic level our hypertext looks like a true network hypertext, but from a more abstract macroscopic level we prefer to regard it as a collection of landmark or overview nodes in a network hypertext which we believe will make it convenient for navigation. An indication of the topology of our hypertext is given in Fig. 2. With our hyperspace organisation and using the HyperTies browser tool, there are a number of different types of navigation and browsing which are possible given a user’s information need. The first of these is to use HyperTies to perform a search for a given string occurrence in the texts of the nodes. This string can be a boolean combination of pairs of ANDed keywords. HyperTies determines the set of nodes in the hypertext which contain the specified string. The user can then Preface
Fig. 2. Topology
of air database
node
hypertext.
176
ALAN F.SMEATON Table
I. Total
number sessions
Table 2. Duration of hypertext student
of hypertext
Number of times used
Number of users
I
6
2 3 4 5 &IO +10
Total duration (h1
Number of “%FS I5 7 5 6 I7
CLI I-2 2-3 34 f4
8 9 8 4 IO 5
use per
choose one of these hits from which to commence browsing. A variation or refinement of this method of browsing is to return to the output of the string search during the session to ensure all nodes containing the given string have been kited by the user. Each node seen during a HyperTies session has an asterisk beside its title indicating that it has been viewed already, although the enforcement of the discipline of visiting all such nodes is left to the user. HyperTies builds a history list of all nodes visited during a session and users can use this for navigation as well as for traversal. Users can also call up their history list and return to a previously viewed node without having to backtrack to the node currently displayed. This utility eases the problem of users having multiple digressions or information needs. Another way of browsing our hypertext is to follow structural links. HyperTies present a PREFACE node as the first screen of information every time a session is commenced. In our case the preface node contains a text overview of the hypertext contents with information links to the overview nodes. The user can follow the information links to overview nodes, the authored content-indicating hierarchy of nodes to support navigation and traversal. In the final browsing option, a user can view an alphabetical listing of node titles referred to as the index. In summary, the browsing options in our system are: (1) (2) (3) (4) (5)
String search to find a single start node and browse String search and explore all the identified nodes Use history list of nodes visited Follow PREFACE to move to topic overview nodes Use index of node titles
and browse
from there
Options 1, 3 and 5 could be classified as unsupervised browsing, option 4 is structured browsing and option 2 is somewhere in between. The hypertext database was used by students in the third year undergraduate courses in Computer Applications and in Applied Mathematical Sciences and students were surveyed in their use of the hypertext system. Fifty students correctly completed and returned the survey, 27 male and 23 female subjects. Those surveys which we did not use were either incomplete or had multiple answers to a single-choice question. In addition, one of the questions asked if the user knew how to sort the names of nodes alphabetically, which is not possible within HyperTies. Those surveys that responded “yes” to this question were also discarded. The results of the survey are detailed in the following section.
Table 3. Where the hypertext
was used Number of users
Used the hypertext Used the hypertext
alone in company
Used the PC serve1 Used another PC in college Used a PC outside college Stage of use of the hypertext: regularly, throughout course periodically, throughout course end of lectures, for a subject overview just before the exam, for revision
37 I3 27 5 18
Table 4. Preferred
methods
of commencmg
Number of users
I 14 I7 39
scss~ons
Use overview node, browse from there Perform string search, browse from result Use index of node titles, browse from there
I5 19 16
Hypertext for learning Table
5. Average path length backtracking
Browse path length (No. of nodes)
177
before
Number of “SeIX
I
I
2 3 4 5 6 7 8 9
2 IO 19 II 3 3 0 I
Table 6. Users rating of the ease of use of HyperTies Easy Scale value Number of users
RESULTS
ON
HYPERTEXT
123456789 25 15 6 2
Impossible 0
2
0
0
0
USAGE
The survey contained 14 questions relevant to this study, which can be grouped under 3 headings, namely when the hypertext was used, how the hypertext was used and a summary of the users’ opinions on the hypertext. When the hypertext
was used
Tables 1 and 2 summarise the frequency and the duration of use of the hypertext, during the academic year. Some students used the hypertext extensively (these tended to be the ones who made most comments in the survey returns) with 30% having 6 or more sessions and 34% claiming to have used it for 4 h or more. On the other hand 12% of the students used the hypertext only once, and 30% say they used it for < 1 h in total. Table 3 gives a breakdown of where the hypertext was used and from that we can see that the majority used it alone, although there was some group work as well. The most interesting data are for the stage of the course at which the hypertext was used. The figures paint a picture of a diverse groups of students, some keenly interested in new software and using it throughout the course while others have their first use of it just before the examination. From individual comments on the survey forms some of the most common statements were that they “would use it more frequently next time, throughout the course rather than just for revision”, and that they “didn’t realise what it could be used for until it was too close to the exam”. Users also reported their sessions as being of 3&45 min maximum, before they claimed that disorientation started to become a problem. How was the hypertext
used
Table 4 summarises the mode of use of the hypertext when a user was commencing a session. Students chose almost equally between following the PREFACE and overview nodes, performing a string search, or using the listing of the node names or titles as a start for a session. Once the users had started browsing the hypertext, their average path length before backtracking is given in Table 5. The majority of users had an average path length of 3, 4 or 5 nodes, before they started to backtrack. Users were asked to answer 7 specific questions from the hypertext. Almost all answers to this and other questions indicated that the answer was obtained by using string searches as opposed to following overview nodes. So for specific information needs users almost always use an unstructured search. Related to the use of string searching in browsing we also asked users whether they would ensure that they visited all nodes in the output set from a string search, in order to guarantee that they Table I. Users requirement of the content of the hypertext Adequate Needs more example nodes Needs less example nodes Needs more overview nodes Needs less overview nodes
5 43 2 10 2
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had covered all information in the hypertext pertaining to a given topic. In answering this question 31 said they would visit all nodes, 11 said they would not and 8 said they did not use the string search facility at all when browsing. What did users think
qf the hypertext?
Finally, we asked users’ opinions of the hypertext. Forty-eight of the 50 subjects said that they would lend it to a friend in another university who was following a similar course, and 46 said that the coverage should be extended to encompass other database material they would study in their final year at college. Forty-three subjects replied that we should definitely distribute the hypertext to students next year, only one was positively against this. HyperTies, and the way we configured it made the system simple to use (Table 6). Other responses were divided into comments on HyperTies and comments on the content. There were many suggestions for improvement to the HyperTies system. The most commonly occurring comment on HyperTies was for the system to provide a mechanism for personalised note-taking or highlighting of the hypertext. Users wanted to annotate the hypertext with their own material as they make margin scribbles and use highlight markers with printed material. Users wanted to create their own links and nodes, but doing this in HyperTies is non-trivial as authoring is a separate process. They would also like navigation tools like bookmarks, despite orientation not being recognised as a problem. These results are consistent with those reported by Leggett et al. [8]. On the content of the hypertext, subjects answered a multiple-choice question. (Table 7). The overwhelming requirement is for more example nodes to illustrate concepts like “database schema normalisation” and the workings of certain SQL statements. This may be due in part to the nature of the material being presented. These topics are ones which are conceptually difficult and in lectures and books are heavily illustrated by worked examples. DISCUSSION Experimental results relevant to our work are reported by Stanton and Stammers[9] who evaluated student performances with structured and exploratory or unsupervised learning environments, where the structured material was CBT and the exploratory was hypertext. That experiment was inconclusive. We offered both structured and unstructured searching within hypertext in the form of overview nodes and string searching respectively. Our results show that students use a mixture of both, with a majority of unstructured searching. When asked for specific information from the hypertext, users almost always use unstructured methods. In our environment users tended not to browse too far before backtracking, usually 3,4 or 5 nodes. This could be because the users would have read enough on the current topic and wanted to move onto something else, or it could be attributed to disorientation caused by the poor support for navigation of the browser tool. Many solutions have been proposed to counter disorientation including bookmarks, compasses, and graphical browsers[3]. These proposals can be grouped into two classes; those that reproduce traditional orientation cues from text evolved over centuries and those that exploit human spatial processing ability. With the former, Kerr[lO] argues that traditional navigation methods may not be appropriate in hypertext, although in our survey users indicated that they wanted bookmarks and text highlighters. With the non-traditional type of navigation, the user still has a problem as browser maps etc. are only navigation aids. Reynolds and Dansereau[l I] have compared A hypermap is a knowledge structure with a hypermaps and hypertexts for learning. node-link-node basis but unlike hypertexts the links are dynamically implemented and the basic nodes can themselves be node-link-node structures. Their experimental results comparing hypermaps and hypertexts found no significant differences in recall between the two but users were more satisfied with hypermaps than hypertexts. Another factor holding up the spread of hypertext is the hypertext authoring process. As mentioned earlier, HyperTies was no help to overall organisation and we need browsers not just an apprentice for suggesting links but which relates the hypertext to an overall plan. Anybody who has authored a hypertext of any size should agree with this. If hypertext usage is to increase, the development of more helpful authoring tools is imperative.
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We believe current hypertext tools cannot replace conventional CBT as they are too unstructured in the order of presentation of material and burden the user with too many distractions from actually reading and assimilating the material being presented. In related work, we are developing tools to help users construct a plan or a route through the hypertext thus creating a richer learning environment [12]. In CBT applications the user’s information need is dominated by having to learn the content of the material and the user should be free from any extra cognitive overheads. The results of our experiments reported in this paper were for using hypertext as adjunct courseware to be used in tandem with lectures and textbooks. With such an application there may be a role for a hypertext presentation of material as a reader may already have an overall grasp or picture of the material and may be seeking clarification or specific information or perhaps to explore the relationships between concepts. Indeed most of our subjects in this survey reported that they used the hypertext for revision, just before the exam, when seeking information on specific topics. REFERENCES 1. Nielsen J., Hypertext and Hypermedia. Academic Press, London (1990) 2. Bernstein M., An apprentice that discovers hypertext links. In Hypertext: Concepts Systems and Applications (Edited by Rizk A., Streitz N. and Andre J.), pp. 212-223. Cambridge University Press, Cambridge (1990). N., Context and orientation in hypermedia networks. ACM Trans. Inform. Sysr. 7, 58-84 3. Utting K. and Yankelovich (1989). retrieval and hypertext: competing technologies or complimentary access methods. School 4. Smeaton A. F., Information of Computer Applications. Working paper, CA-0191, Dublin City University (1991). 5. Jonassen D. H. and Mandl H. (Eds), Designing Hypermedia for Learning. Springer, Berlin (1990). 6. HyperTies Author’s Guide, Cognefics Corporation, Princeton, N.J., March (1989). Redwood City, Calif. (1989). 7. Elmasri R. and Navathe S. B., Fundumenfuls of Database Systems. Cummings, In Designing Hypermedia for Learning (Edited 8. Leggett J. J., Schnase J. L. and Kacmar C. J., hypertext for-learning. by Jonassen D. H. and Mandl H.), PP. 27-38. Springer. Berlin (1990). 9. Stanton N. A. and Stammers R. B.‘, Acomparison of structured and unstructured navigation through a CBT package. Computers Educ. 15, 159-163 (1990). cues vs mental models. Inform. 10. Kerr S. T., Wayfinding in an electronic database: the relative importance of navigational Process. Mgmr 26, 511-523 (1990). 11. Reynolds S. B. and Dansereau D. F., The knowledge hypermap: an alternative to hypertext. Computers Educ. 14, 409416 (1990). In AI and Cognitive Science 91 (Edited by 12. Smeaton A. F. and Guinan C., Intelligent searching through hypertexts. Sorenson H.). Springer (1992).