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2012 | Buch

GSN - The Goal Structuring Notation

A Structured Approach to Presenting Arguments

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Über dieses Buch

Goal Structuring Notation (GSN) is becoming increasing popular; practitioners use it in the railway, air traffic management and nuclear industries, amongst others. Originally developed to present safety assurance arguments, GSN need not be restricted to safety assurances only; in principle, you can use it to present (and test) any argument. Anyone wishing to support, or refute, a claim can use GSN. Written by an experienced practitioner, The Goal Structuring Notation is both for those who wish to prepare and present compelling arguments using the notation, and for those who wish to review such arguments critically and effectively.

To emphasise the versatility of this approach The Goal Structuring Notation presents examples and questions based on diverse subject areas including Business Management, Drama, Engineering, Politics and Astrobiology. Simple examples introduce each symbol of the notation before introducing more complex structures which illustrate how the symbols work together in practical scenarios. To aid learning, questions and problems augment the text, so that the reader may reflect upon and try out the new concepts and principles presented.

As a comprehensive instruction in the basics of GSN and it’s application, The Goal Structuring Notation also serves as a references or manual for the practitioner to dip into as problems are encountered or as a key resource for engineers working in those industries which require a clear description of the notation, covering the initial principles and showing why each piece of the notation is necessary.

Originally developed to present safety assurance arguments, GSN need not be so restricted. GSN - The Goal Structuring Notation presents examples from diverse subject areas, including business management, drama, engineering, politics and astrobiology.

Inhaltsverzeichnis

Frontmatter
Chapter 1. Introduction
Abstract
This introductory chapter presents the purpose of the book and the purpose of GSN, the notation described herein. It identifies the intended audience; how they could use the book to greatest advantage; and summarizes the content.
John Spriggs
Chapter 2. Goals
Abstract
The Goal Structuring Notation is a notation for structuring Goals but, what is a Goal and why would we want to structure them?
When using the notation to represent arguments, the Goals represent claims. We can use Goal Structures to persuade others of the truth of our claims. This chapter introduces the symbol and text convention to be used to represent Goals in these structures.
John Spriggs
Chapter 3. Contextual Information
Abstract
The truth of a claim depends on the context in which you make it. For example, if the claim is, “It is Safe”, what is it that is safe? For that matter, what is “Safe”; what do they mean by that word? You could detail the Goal statement to include all this additional information, but then it would be too cumbersome. The solution is to declare the context explicitly. This chapter introduces symbols and text conventions for declaring context; this includes the Model symbol, which is not part of the core notation, but may occasionally be encountered “in the wild”.
John Spriggs
Chapter 4. How do Goals Make Arguments?
Abstract
A Goal Structure is used to show how our claim, represented by a Goal, is the consequence of simpler Sub-Goals. This chapter introduces the symbol used to represent the thread of the argument and gives simple examples, showing how to construct and read simple arguments (and fallacies).
John Spriggs
Chapter 5. A More Practical Example
Abstract
We now have enough notation to do something practical. An example is presented arguing that a (hypothetical) departmental business plan is complete, and showing how such an argument can be used as a tool that any department in the company can use to “dumb down” preparation of their departmental business plan without loss of confidence in the results. This example introduces ideas for partitioning large arguments for publication, for unambiguous labelling of parts of the argument, and for initial roughing-out of the drawings
John Spriggs
Chapter 6. Argument Strategy
Abstract
This chapter introduces the concept of Argument Strategy, which is used to express the rationale behind choice of Sub-Goals. It describes the symbol and text conventions used to represent Strategy in Goal Structures. Having now introduced the basic argumentation symbols, we are in a position to construct some serious arguments. This chapter also presents a process flow, formalising how this can be done by developing claims and strategies.
John Spriggs
Chapter 7. A Bit More Contextual Information
Abstract
Although the notation introduced so far can be used to represent practical arguments, additional rationale is often required. This chapter introduces the symbol and text convention used to justify elements of the argument. The Justification may also point out, by reference, to an external argument; for example, I may say that a particular Sub-Goal is true because someone has already set that precedent elsewhere and it is applicable in my context. When presenting an argument, it is very important to state explicitly all of the assumptions that you have made. This chapter describes the Assumption symbol and the text conventions for stating assumptions.
John Spriggs
Chapter 8. The Argument is Incomplete…
Abstract
We have seen how to construct an argument in support of a claim by successive decomposition. This cannot go on forever, when have we done enough and how do we terminate our threads of argument? This is the job of the Solution symbol. Solutions constitute the evidence that completes and supports the overall argument. This chapter describes the connection, labelling and text conventions for Solutions, along with methods of justifying how Evidence supports a particular Goal. Sometimes the evidence may actually be another argument; this Chapter identifies a symbol sometimes used to show this, a Goal Developed Elsewhere. It is not part of the core notation, but you may find it in existing arguments.
John Spriggs
Chapter 9. The Argument is Ready for Review…
Abstract
Early on in its development, you ought to get your argument reviewed by someone else; preferably your Customer, if you have one. This chapter introduces additional notation that you can use to let your reviewers know where in your Goal Structure there is more to be done. These additions include the Goal to be Developed symbol, which is also known as Undeveloped Goal. Some people like to add explanatory notes to their Goal Structures; this chapter also suggests some symbols for this, but note that they are not part of the formal notation and they can clutter your diagrams. Finally, I start development of a checklist that may be used by the reviewer of arguments presented in GSN; the author of such arguments should always use it…
John Spriggs
Chapter 10. A More Interesting Example
Abstract
This chapter poses a currently unanswered question; from it, I develop a Top Goal and Context for a Goal Structure. It is a conjecture for which we can argue. By decomposing this Top Goal and its Sub-Goals, we can see where Evidence is available and where it is weak or missing. The Goal Structure enables us to test the argument; we can see where more work needs to be done in support of the conjecture and where we have done sufficient for the current purpose. In this chapter, I use the example to illustrate how an argument may be made more compelling by introducing additional evidence from an independent source.
John Spriggs
Chapter 11. Generic Arguments
Abstract
The example introduced by the previous chapter contained sub-arguments about different types of sensor device. New sensor types are in development; it would be more efficient if we were to develop a generic argument for any type, and then fill in a copy with the details of new devices as they become available. This chapter uses the sensor example to show how to develop generic goal structures for re-use. It introduces new symbols and text conventions for a Generic Goal (or Goal to be Instantiated), plus some new arrow types representing Multiple Relationship, Optional Relationship and OR Relationship.
John Spriggs
Chapter 12. Missing Evidence
Abstract
In Chap.​ 10, I noted that there was insufficient evidence to support one of my claims. I also noted that evidence from a famous scientific experiment should be available to support the argument, but it is not; the evidence is missing. This chapter examines what you can do in general if the expected evidence does not materialise, and recovers the situation for the example.
John Spriggs
Chapter 13. Counter-Evidence
Abstract
Chapter 12 looked at the problem of not finding evidence that you need to support your argument. A potentially worse situation is when evidence is presented that refutes your argument. This chapter suggests strategies for coping with such “counter-evidence”.
John Spriggs
Chapter 14. Process Arguments
Abstract
Chapter 8 mentioned process arguments when considering sources of evidence. In that context, the process argument is to demonstrate that the right evidence was obtained in the right way. In general, you would deploy a process argument to show that a process is fit for purpose; in particular that it is fit for the purpose for which it is to be, or has been, used. This chapter presents a generic high-level process argument, and discusses decomposition of the key Sub-Goals.
John Spriggs
Chapter 15. A Brief on Modular GSN
Abstract
Dr Tim Kelly formalised the Goal Structuring Notation for safety assurance and, in 1998, published it in his University of York doctoral thesis. Since then, development work has continued at York, and elsewhere. This chapter briefly summarises one of those developments, the concept of modular arguments; my intention is to give you enough to decide whether you want to find out more. No problems are set.
John Spriggs
Chapter 16. A Summary of Goal Structuring Notation
Abstract
This chapter presents a Revision Guide, a summary of the Goal Structuring Notation. It illustrates each symbol in turn with the rules for its shape and content, plus references to examples elsewhere in the book. Note that it does not cover ‘Modular GSN’, see Chap.​ 15 for that.
John Spriggs
Backmatter
Metadaten
Titel
GSN - The Goal Structuring Notation
verfasst von
John Spriggs
Copyright-Jahr
2012
Verlag
Springer London
Electronic ISBN
978-1-4471-2312-5
Print ISBN
978-1-4471-2311-8
DOI
https://doi.org/10.1007/978-1-4471-2312-5