CS846 Paper Review Form - Winter 2012

Reviewer: Preksha Sisodia	

Paper Title: The "Physics" of Notations: Toward a Scientific Basis for Constructing Visual Notations in Software Engineering

Author(s): Daniel L. Moody

1) Is the paper technically correct?
 [a] Yes
 [ ] Mostly (minor flaws, but mostly solid)
 [ ] No

2) Originality
 [a] Very good (very novel, trailblazing work)
 [ ] Good 
 [ ] Marginal (very incremental)
 [ ] Poor (little or nothing that is new)

3) Technical Depth
 [ ] Very good (comparable to best conference papers)
 [a] Good (comparable to typical conference papers)
 [ ] Marginal depth
 [ ] Little or no depth

4) Impact/Significance
 [ ] Very significant
 [a] Significant
 [ ] Marginal significance.
 [ ] Little or no significance.

5) Presentation
 [ ] Very well written
 [a] Generally well written
 [ ] Readable
 [ ] Needs considerable work
 [ ] Unacceptably bad

6) Overall Rating
 [ ] Strong accept (award quality)
 [a] Accept (high quality - would argue for acceptance)
 [ ] Weak Accept (borderline, but lean towards acceptance)
 [ ] Weak Reject (not sure why this paper was published)

7) Summary of the paper's main contribution and rationale
   for your recommendation. (1-2 paragraphs)

It is important to have a precise yardstick for judging the “goodness” of visual notations.  The ease, speed and accuracy with which a human mind can process a representation are considered a good measure for goodness of visual notation. Where diagrams ease the task on one side, a bad diagrammatic modelling can prove to be ineffective in comparison to textual representation. Some problems with the existing processes are that most of the visual modelling is not documented and are based on common sense. This phenomenon is referred as “unselfconscious design culture”- Visual notations are neither based on design principles nor empirical evidences instead on intuition and tradition. This results in lack of creativity in developing the area of study. The prescriptive theory introduced in this paper states the principles for designing effective visual notations. This brings in a scope for standardization of the visual representation. The principles have been mentioned at the end of this document. To conclude, there is a lot of redundancy, intuitiveness( favourable to a certain extent)in the use of visual notations. Also there are no good reasons to back the use of notations in software engineering. This calls for adopting a systematic approach for building graphical notations in respective domain which could improve the cognitive effectiveness.

The author has presented an in-depth explanation of concepts and also a good background of the work that it is based on. The author has researched a number of domains and analyzed the impact of physical notations on them. The goals and restrictions are very clearly stated. Relevant examples have been provided. And it also talks about the most basic thing that is used widely in software engineering.

8) List 1-3 strengths of the paper.  (1-2 sentences each,
identified as S1, S2, S3.)
S1 : It brings to fore one of the neglected topics in software engineering which holds a reasonably important place. Also, the use of design principles in the formation of notations would take away a lot of ambiguity and bring in a more concise and easy to grasp graphical notation along with a scope for standardization.
S2 : This claims by the author of this paper is backed by a lot of previous work which claims the importance of pictorial representations, its advantage over textual processing by the human brain making the claim of this paper even stronger
S3: A lot of relevant examples have been included in the paper which help in explaining the concepts better.

9) List 1-3 weaknesses of the paper (1-2 sentences each,
identified as W1, W2, W3.)

W1 : The use of the principles of visual notations may not be very effective for 

Detailed summary and review of the paper:

It is important to have a precise yardstick for judging the “goodness” of visual notations.  The ease, speed and accuracy with which a human mind can process a representation are considered a good measure for goodness of visual notation. Where diagrams ease the task on one side, a bad diagrammatic modelling can prove to be ineffective in comparison to textual representation.

Some problems with the existing processes are that most of the visual modelling is not documented and are based on common sense. This phenomenon is referred as “unselfconscious design culture”: Visual notations are neither based on design principles nor empirical evidences instead on intuition and tradition. This results in lack of creativity in developing the area of study.

It is observed that the ontological analysis of software engineering notations take into account only their  semantic validity and does not analyse the syntactical completeness. Cognitive Dimensions (CD) of Notations: Theory for analysing and describing. It can be considered as the starting point of research in this field. The paper draws an analogy between the theory of communication by Shannon and weaver and talks about the design space and solution space. This is a descriptor theory.

The prescriptive theory states principles for designing effective visual notations. The nine principles stated have a modular structure and can be modified as per future work. Below listed are the nine principles and their one line descriptions.
Semiotic clarity: For a notation to satisfy notational system, there has to be a one-to-one mapping between symbols and constructs.
Perceptual Discriminability: Ease and accuracy of distinguishing between various symbols.
Semantic transparency: Use symbols such that the meaning can be inferred intuitively.
Complexity Management: Deals with number of graphic elements in the representation such that it is most effective for the user to perceive. 
Cognitive integration:  Ability to integrate information from more than one source.
Visual Expressiveness: The effective use of the visual variables in the representation of graphic elements.
Dual Coding: using text along with graphical representation to enhance the essence of what is conveyed.
Graphic Economy: Maintaining a balance number of symbols in notations, such that a user is comfortable enough to recognize them.
Cognitive Fit: Adopting notations that are specific to the area of work.

To conclude, there is a lot of redundancy, intuitiveness (favourable to a certain extent) in the use of visual notations. Also there are no good reasons to back the use of notations in software engineering. This calls for adopting a systematic approach for building graphical notations in respective domain which could improve the cognitive effectiveness of the data being represented.