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Systems Analysis Dr. Vicki Sauter and Friends Professor, Information Systems University of Missouri Saint Louis InfoSys 3810 Week Three 2013.

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Presentation on theme: "Systems Analysis Dr. Vicki Sauter and Friends Professor, Information Systems University of Missouri Saint Louis InfoSys 3810 Week Three 2013."— Presentation transcript:

1 Systems Analysis Dr. Vicki Sauter and Friends Professor, Information Systems University of Missouri Saint Louis InfoSys 3810 Week Three 2013

2 Systems Analysis and Design Five fundamental, separable, yet interrelated elements  Planning … including requirements elicitation  Analysis  Design (including logical design and physical design ( or preliminary design and detailed design)  Implementation … which includes coding, test, and deployment  And  Maintenance Last Week

3 Systems Analysis and Design The waterfall model … a sequential process where one phase is completed before the next is started …  There is significant formalism to this model  There is little actual use of this model in today’s Information Systems world The Waterfall model is just one systems development methodology Last Week

4 Systems Analysis … A Definition Systems Analysis is an explicit formal inquiry carried out to help someone identify a better course of action and make a better decision than he might otherwise have made.  identification and re-identification) of objectives, constraints, and alternative courses of action  of the probable consequences of the alternatives in terms of costs, benefits, and risks  presentation of the results in a comparative framework so that the decision maker can make an informed choice from among the alternatives © Principia Cybernetica Web Last Week

5 Systems and Systems Analysis Definition of a System A system is composed of interacting parts that operate together to achieve some objective or purpose. a system is intended to "absorb" inputs, process them in some way and produce outputs (where outputs are defined by goals, objectives or common purposes) Last Week

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8 Different perspectives … for different needs 8 / 49 Last Week

9 © R.A. Navarro Zachman Framework, Cont Last Week

10 Business Rules A business rule is a rule of a business, company, or corporation. It is a rule that defines or constrains some aspect of business and always resolves to either true or false. Business rules are intended to assert business structure or to control or influence the behavior of the business. Business rules describe the operations, definitions and constraints that apply to an organization. Business rules can apply to people, processes, corporate behavior and computing systems in an organization, and are put in place to help the organization achieve its goals. Wikipedia.net Last Week

11 The Requirements Phase of Process Development Definition ( Wikipedia)  A requirement is a documented need of what a particular system should be or do.  A requirement can be a description of what a system must do. This type of requirement specifies something that the delivered system must be able to do.  Other types of requirements specify something about the system itself, and how well it performs its functions. © R.A. Navarro11/42

12 Business Processes Design And Development Must Be Based On Formal Requirements  Functional requirements  Non-functional requirements  Pseudo requirements Formal Requirements © R.A. Navarro12/42

13 Methodologies for Requirements Elicitation  Archival document analysis  Document review  Inspiration / Imagineering  Interviews  Surveys or Questionnaires  Delphi Method  Direct Observation  Contextual Inquiry  Concept Elicitation  Focus Groups  RAD / JAD  Prototyping Formal Requirements Individual- oriented methods Group- oriented methods © R.A. Navarro13/42

14 Creativity

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16 The Calf Path One day thru the primeval wood A calf walked home, as good calves should, But made a trail all bent askew, A crooked trail, as all calves do. Since then three hundred years have fled, And I infer, the calf is dead; But still behind he left his trail, And thereon hangs my mortal tale. The trail was taken up next day By a lone dog that passed that way, And then a wise bell-weather sheep Sliding into a rut now deep, Pursued that trail over hill and glade Thru those old woods a path was made.

17 The Calf Path And many men wound in and out, And dodged and turned and bent about, and uttered words of righteous wrath Because “twas such a crooked path” But still they follow-do not laugh- The first migrations of that calf. The forest became a lane That bent and turned and turned again; This crooked lane became a road where many a poor horse with his load Toiled on beneath the burning sun, And traveled some three miles in one.

18 The Calf Path The years passed on in swiftness fleet, The village road became a street, And this, before the men were aware, A city’s crowded thoroughfare. And soon a central street was this In a renowned metropolis; And men two centuries and a half Followed the wanderings of this calf. Each day a hundred thousand strong Followed this zigzag calf along; And over his crooked journey went The traffic of a continent.

19 The Calf Path A hundred thousand men were led By one poor calf, three centuries dead. For just such reverence is lent To well established precedent. A moral lesson this might teach Were I ordained and called to preach. For men are prone to go it blind Along the calf paths of the mind; And work away from sun to sun To do what other men have done. Sam Walter Foss

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30 Class Discussion

31 Class Exercise Re: The UMSL Library System  You have all researched the UMSL Library Business Rules  You all understand the function of a library from a student’s point of view  Develop an Improved set of business rules Be Creative

32 Notes Networking Expectations are defined on the class website  There is a networking opportunity tomorrow morning …  Breakfast and Business  7:30 am in the MSC  Featuring Juli Niemann … “What Recovery”

33 Systems analysis There are two fundamentally different ways of approaching systems analysis  Process View  Data View

34 Systems Analysis … Processes vs Data Points of View

35 Systems Analysis … The Process View A Process is defined as  A sequence of related tasks which combine to accomplish a function  A transformation

36 Systems Analysis … The Process View A system may be “modeled” using a process documentation formalism  A language  A representation Schema Typical among such schema  Visio  IBM Flow-Charting Templates  IDEF

37 Systems Analysis … Data View Data are values of qualitative or quantitative variables  Data in are typically represented in a structure, often tabular, a tree, or a graph structure.  Data are typically the results of measurements  Data as an abstract concept can be viewed as the lowest level of abstraction from which information and then knowledge are derived

38 Systems Analysis … Data View Data Information Knowledge Wisdom

39 Systems Analysis … Data View

40 DFD’s show  Input to and output from the system across the system boundary  Inputs and outputs to and from system elements  Flow among systems elements  Storages DFD’s do NOT show timing, control etc.

41 Class Exercise Working in groups: Define the data necessary to support a system developed to meet YOUR new library business rules


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