A Diagram Drawing Tool For SemiAutomatic Assessment Of

A Diagram Drawing Tool For Semi–Automatic Assessment Of Conceptual Database Diagrams Firat Batmaz, Chris Hinde Computer Science Loughborough University

Why Diagrams ? n Many Diagram Based Questions in HE n in Computer science, Mechanical Engineering, Systems Engineering etc. . . n Data Flow Diagrams, Class Diagrams, ER Diagrams

Why Conceptual Database Diagrams? n Namely “Entity Relationship Diagrams” n n n Common Extensive practice Range: Simple – Complex Open-ended domain No single best solution

Why Semi–Automatic Assessment? n Computer Aided Assessment n n Coursework and Examination Self-assessment and revision support Enhanced learning Fully–Automatic Assessment (So Far) n n n Not so many studies in automatic diagram assessment. Focus on Grading. "Free" diagram assessment has not been successfully achieved.

Why Semi–Automatic Assessment ? n n Form the foundation for fully automated assessment in future. The research results have some immediate practical uses.

So , The aim is n To computerise the existing manual assessment as much as possible.

The existing manual assessment n Marking n n Slow start Speeds up Repetition of judgements. There a number of identical diagram components in student solutions.

Identical diagram components in Student Solutions Loan Student A Member Reserve Book Title has Student B Librarian Buy Book Title has Student C Member Reserve Book Title has Book Copy Publisher

The Semi–Automatic Assessment System n n n Groups identical segments of the student’s diagrams. Asks the assessor to approve the correctness of a diagram fragment from the each of the different groups. Therefore the assessor would be involved in the marking process only for the number of diagram groups rather than the total number of student diagrams.

Diagram Groups in Student Solutions Group 1 Group 2 Student Reserve has Group 3 Book Copy Book Title has Loan has Book Title Reservation Book Title Book Copy Group …

The Diagram Groups n n The correctness of the grouping depends on the criteria used to match the diagram pieces. The smallest diagram piece in each group can be either an entity or a relationship for a conceptual database diagram.

Entity Matching n Entities in different diagrams could be considered as matched exactly if they have n same entity name and n n same number of attributes with same name. Pretty tight definition n n Increases assessor’s involvement Not Sufficient

Entity Matching Entities are matched. ID Book ID An Entity From Diagram A An Entity From Diagram B

Entity Matching But the entity matching is not valid. Diagram B Diagram A Book Title Reserve Book Loan Has ID Member Has Book ID Title Author ISBN Book Title Ideal Diagram Reserve Has Member Loan Book Copy No Price Purchase Date Reserve Member Loan Book Copy

Entity Matching n n The definition should also include contextual attributes of an entity. In the KERMIT approach contextual meaning of an entity is given explicitly by forcing the students to highlight the related text in the scenarios.

Entity Matching with Scenario References Diagram A Book Title Ideal Diagram Reserve Loan Has ID Member Book Title Author ISBN Book Title Reserve Has Member Loan Book Copy No Purchase Date Price Scenario ----- Each book copy has got a unique copy number and their price and purchase date is recorded. ---

The problems of the scenario referencing n Finding a related text to diagram components is not a straightforward task. n n Direct correspondence sometimes doesn’t exist. Designing a conceptual database model is an iterative process.

Designing A Conceptual Database Model verify Real world view Analyse Problem Statements Describe Map verify Teaching And Assessing Model (e. g. ERM)

The links to the scenario text n The initial diagram can have n n Intermediate and final diagrams n n direct link to the scenario text. The diagram is modified by applying design rules and constraints. The final diagram can have n indirect links to the scenario text n requires all the steps between the initial and the final diagram to be seen explicitly.

The links to the scenario text DB Scenario ---------------Lecturer --------------------------------- Initial Diagram Staff Lecturer ---------------------------Head of department --------------------------------------- Final Diagram HOD Manage Has Has Department

The links to the scenario text DB Scenario Initial Diagram Final Diagram Lecturer Merge HOD Direct links Indirect links Staff

The links to the scenario text Initial Diagram Final Diagram Lecturer Merge Staff HOD Direct referenced (DR) components Indirect referenced (IR) components

Intermediate diagrams n n Not all intermediate diagrams are important. n necessary to be able to match diagram components. Initially “Price” is an attribute of an existing entity “Book Title” later on, it becomes an attribute of an entity “Book Copy”. We only consider the previous diagrams leading to the IR-component.

Diagram Modifications which result in IR-components n n n Merging two entities Splitting an entity into two entities Converting a “many to many” Relationship to an Entity

Diagram Modifications Intermediate Diagram Final Diagram Events • Merge • Split • Convert Indirect referenced (IR) components

Self-explanation n Student actions must be interpreted to be able to recognise an event. Even then, the interpretation may not be what the student intended. The student needs to explicitly mention their intention during the design.

Self-explanation n Self-explanation (SE) is a very effective learning strategy resulting in deep knowledge. The main problem of self-explanation whilst solving the problem is the high cognitive load. The proposed diagram editor is designed to reduce the cognitive load of self-explanation.

Diagram Editor n n The prototype diagram editor is based on automatic graph drawing. Students enter the component type and name n n the tool draws the diagram. Students then can focus more on designing than drawing.

Diagram Editor Scenario Text Section Diagram Display Section Diagram Modification Section

Function Button Example Split Event Intermediate diagram "Split" function button box

Function Button Example After Split Event

An Experiment is Required n n The diagram editor has two aspects. To capture contextual meaning of diagram components to help the examiner during marking. To provide an environment for the student to enter their design. The editor has a very different environment from those of traditional diagram drawing tools.

Experiment n n People who have studied database design at university level. An introduction session: n n n How to use the editor on one example database scenario. The example scenario uses one of the function buttons. The users are asked to design a conceptual database diagram for a similar scenario.

Results(1) n n All the participants managed to draw the correct diagram. Although the given scenario didn’t allow them to design the diagram without using the function button, none of them failed to use the editor.

Results(2) n n The required function button for the design expects an entity name from the user. All participants named the entity differently as expected. Different names for the same entity are not a problem for our approach since contextual information of the component is the main criteria for the entity match and this context is provided by the usage and recording of the function button.

Conclusion n This paper proposes a new diagram editor which alters the traditional diagram drawing in order to make the assessment process suitable for semi-automation. This alteration enables the assessor to better understand the student thinking and give accurate feedback to students. The prototype editor provides an environment in which the students can design the database model methodically.

Further works n n Types of user and scenario are the main factors which could affect the experiment’s results. The users could be students who are learning about conceptual database design, rather than experienced designers. n n The interface needs to be made more user-friendly. The scenario could be written in such a way that it enforces the use of different combinations of the function buttons. n All function buttons for different scenario types will be implemented.

Further works n n n The other part of our semi–automatic assessment is the marker environment. The editor is a beneficial tool only if the contextual information of each component can be used by the marker environment to match them correctly. The implementation of the marker environment and experiments on it are also very important to complete the research.

Questions Please ? Thank you