Systems eng for managers-cheat sheet

Notions of ‘systems’ as ‘complex wholes’ abound; ‘systems of interest’ to engineers are understood In a distinctive way. We reveal our systems thinking through language. Images, models, specifications & references that assist understanding. We rely on ‘user-judged’ words such as system, project, risk. Network, reliability, environment, need, effectiveness. Their meaning Is socially constructed – even within a single discipline. System a system Is a set of Interrelated components working together towards some common objective or purpose.

System Concept System is something hat maintains its existence and functions as a whole through interaction of its parts. Hierarchy and Emergence The notion of hierarchy suggests that every system has a CONTAINING SYSTEM, and in turn contains other systems. When entitles combine In some relationship properties and capabilities emerge which none of the entities, by itself, possesses. Communications and Control “information” is transferred between entities and between the system and its environment.

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A system retains its identity through feedback and control. Holism System have Aggregates (When we have a set f entitles such that at least one subset of entitles is not related to every other subset, then we have an aggregate of entities) ; what missing from aggregates found in systems; the sense of organic wholeness/the need for emergent properties/the need for maintenance of identity/So a system Is not Just any collection of stuff.

System Must have Elements/Interconnections/A function or purpose Function the outcome and behaviors of the system Function due to structure (Characteristic Action) occurs because of entity interaction/independent of observer/a product of design”/in the solution domain/Mission function (Defines desired emergent properties) due to human intent/dependent on observer/Len the problem domain State The state of a system at a moment of time is the set of relevant properties which the system has at that time. A system may have several states/States are mutually exclusive I. E. System cannot be in more than one state at any given time/ but It may get to a given state through several ways/elf a system can reach the same final state from different initial states through different ways then it has the property of Equability. Modes Ways of achieving state transitions Why Systems work well Resilience Measure of a system’s ability to survive and persist in a variable environment, Self-organization The capacity of systems to make their own structure more complex – learn, diversify, evolve/Systems structure themselves into new structures Hierarchy Elements to subsystems to larger subsystems etc.

Why systems surprise We keep focusing on “events” rather than patterns, behavior and structuralize minds In a non linear world” [Those system boundaries don’t really exist! /Longing factors – at any time the system Input that Is most Important Is most imitating/Delays/Bounded rationality Shoo-technical Systems (SST) It was recognized by these researchers that: Organizations consist of social and technical systems (The social system: people, their values, culture, norms etc. [The technical system: equipment, processes, tools technology etc. /Organizations perform functions and achieve objectives through the interactions of these systems Organizations are therefore systems comprising technical and social elements that together achieve the hardware and software but where the operators and operational processes are not normally considered to be part of the system. The system is not self-aware. Socio- technical systems: Systems that include technical systems but also operational processes and people who use and interact with the technical system. Socio-technical systems are governed by organizational policies and rules.

Systems – Effectiveness Classical systems engineering definitions of system effectiveness tied to “fitness for purpose”, I. E. To system missions/A system is said to be effective to the extent that it meets its mission requirements. /Missions have a social context! /Effectiveness models created using Measures of Effectiveness (MOE) to indicate characteristics that help achieve a system’s intended purpose. /Even the most technical system has its missions defined in a social context – I. E. Its mission is in a socio-technical context. Hence their effectiveness can only be sensibly Judged in a esoterically context. /Len this sense an engineered system is or belongs to an SST having social and technical subsystems that interact, influence and constrain each other to achieve the system purpose. Significance of detail and dynamic complexity in systems engineering. The essential purpose of SE is to allow us to handle complexity. Detail complexity arises from the system having many parts. Dynamic complexity arises due to the relationships between the parts.

Recognizing such complexity is essential if we are to create effective systems, and to recognize that “fiddling” with complex systems may lead to results that we cannot anticipate. This is particularly so where dynamic complexity is high. SST characteristics Openers. Emergent properties: Properties of the whole system that result from the system components and their relationships. Non-deterministic They do not always produce the same output when presented with the same input because the systems’ behavior is partially dependent on human operators.

Complex relationships with organizational objectives The extent to which the system supports organizational objectives does not Just depend on the system itself. Complexity, therefore: Non-determinism/counter-intuition – impossible to precisely anticipate system behavior/Limited “decomposability’ – can’t study system properties by examining the parts/Distributed nature of information Complex relationships with organizational objectives The extent to which the system supports organizational objectives does not Just depend on the system itself.

Emergence Social elements can be in varying states – hence the emergence obtained may vary. Where isms used Where the people involved are aware that a problem exists, but cannot define it/Where there are different points of view and, possibly, conflict/Where changing one part of a system may have an unknown impact on other parts/Where there is a combination of the above Significance of Root Definitions and CATTLE in SMS (Example) Root definitions are definitions of systems that should exist in our situation if our objectives are to be met.

They allow us to then produce conceptual oodles of such systems so that we can compare those with reality and identify any missing elements that need to be fixed in the reality. CATTLE analysis allows us to create such root definitions, and to analyze existing root definitions for completeness.

Customers = the users of the page Actors = the author of the page Transformation = requirement for a page describing Root Definitions Hallucinating (world view that makes T meaningful) = that the suite of which this page is a part will contribute to the this project Environment = the restrictions of web technology; the time available to impose the page Ex: A system to contribute to a suite of web pages concerning Soft Systems Methodology by writing and designing a web page explaining root definitions, in order to contribute to the resources available for the teaching and learning of SMS.

Conceptual Model Provide an account of the activities which the ideal system must do in order to fulfill the requirements of the root definition (1 Appreciate the color scheme of the property 2 Decide the scope of the painting task 3 Decide the color to paint the house 4 obtain materials 5 paint the fence 6 Define assures of performance 7 Monitor 1-5 8 Take control action) Methodology SMS is a methodology that aims to bring about improvement in areas of social concern by activating in areas of social concern by activating in the people involved in the situation a learning cycle. The learning takes place through the iterative process of using systems concepts to reflect upon and debate perceptions of the real world, taking action in the real world, and again reflecting on the happenings using systems concepts/ The reflection and debate is structured by a number of systematic models. These models are conceived as holistic conceived as holistic ideal types of certain aspects of the problem situation rather than as accounts of it.

It is taken as given that no objective and complete account of a problem situation can be provided. SMS Methodology 1 . The problem situation unstructured 2. The problem situation expressed (gather info about structure and processes; Summarize into a “rich” picture; Analysis) 3. Root definitions of purposeful activities (need to identify relevant systems as concise well formulate statements; Draw out essence of What, Why, Who is to do it, Who is to benefit/suffer, constraints) 4.

Conceptual models of the systems named in 3 (Provide an account of the activities which the ideal system must do in order to fulfill the requirements of the root definition; Use verbs to capture the model(s)) 5. Compassion of 4 with 2 (Aim is to generate debate about possible changes to improve problem situation; Forced to check assumptions) 6. Changes:systematically desirable, culturally feasible 7.

Action to improve the problem situation (implementation of changes that are desirable and feasible; can classify as attitudinal, structural or procedural )Pros of SMS(The ability to solve soft problems here hard techniques fail/Takes social, political, and power distribution issues into consideration through the application of cultural stream analysis/Support different viewpoints through rich pictures/Can be used for learning in addition to solving problems/Can be used in messy situations needing improvement but where no specific improvement goals and objectives are evident/Allows for new and imaginative solutions to be discovered/Very useful in the beginning of solving a problem to find out about the problem situation and elicit improvement requirements) Criticisms of SMS(SMS is used to solve some “ill-parts” of a system but t doesn’t build a whole system/let does not tell you how to build a system- in the classical engineering sense/The power handling part seems problematic where/ managers always have the upper hand/Management are not so happy about the open ended nature of SMS/Heavy weight and time consuming process/Limited in the design of a new system. Distinction between soft and hard situations important/ examples-2 systems approaches integrated (Because our approaches to issues in problems that can be solved using classical engineering means. Soft situation present vague issues.

Integration is possible:l . Conceptual phase – using soft ethos to identify requirements and identifying system boundary, and then using hard methods to proceed. 2. Design Phase – using soft methods to highlight assumptions and resolving conflicts. 3. Test and Evaluation Phase – using soft methods to work through issues and problems between stakeholders that may arise due to testing problems) chi-system Behavior Patterns Exponential growth/Goal-seeking/S- Shaped/Oscillation Causal Loop Diagrams (Clods) (Reinforcing(increasing rate)/ Balancing(Corrective action)) Used to represent cause-effect relationships between system variables, depicting feedback loops.

They help us to:understand the problem and system behavior/Capture hypotheses about the dynamic behavior/Help us to model the structural feedback. Key CLAD Elements: Variable:a condition. Action,decision,situation that can affect or be affected by other variables- quantitative or qualitative(soft). Arrow(link):indicates causal relationship between two variables. Causal Loops:A conceptual tool starting from a cause trace its effects through intermediate variables back to the original cause I. E. From a loop(of cause/ effect)-emphasizing that causal relationships among things. By better understanding Hess relationships,we can gain insights to the dynamics involved.

Feedback Negative (Change is counteracted: Stabilizing/Self-regulating ‘”Goal-seeking”/Homeostasis, e. G. Temperature regulation in organisms and machines) Positive (Change leads to further change in same direction: Growth enhancing/Potentially destabilize, e. G. Vicious cycles, self-fulfilling prophecies. System Archetypes: 1 . Model or first form; the original pattern or model after which a thing is made. 2. (in Jungian psychology) an inherited mode of perception or response linked to the instincts, which is part of the collective unconscious. Ten archetypes are generally acknowledged as forming the set of tools that reveal patterns of behavior in systems-I .

Limits to Growth (aka Limits to Success); a reinforcing process of accelerating growth (or expansion) will encounter a balancing process as the limit of that system is approached. It hypothesizes that continuing efforts will produce diminishing returns as one approaches the limits/2. Shifting the Burden; a problem symptom can be resolved either by using a symptomatic solution or applying a fundamental solution. It hypothesizes that once a symptomatic solution is used, it alleviates the problem humpty and reduces pressure to implement a fundamental solution, a side effect that undermines fundamental solutions. /3. Eroding Goals; a gap between a goal and an actual condition can be resolved in two ways: by taking corrective action to achieve the goal, or by lowering the goal.

It hypothesizes that when there is a gap between a goal and a condition, the goal is lowered to close the gap. /4. Escalation; occurs when one party’s actions are perceived by another party to be a threat, and the second party responds in a similar manner, further increasing the threat/ 5. Success to the Successful/6. Tragedy of the Commons; if the total usage of a common resource becomes too great for the system to support, the commons will become overloaded or depleted and everyone will experience diminished benefits. ‘ 7. Fixes that Fail/8. Growth and Underinvestment/9. Accidental Adversaries/10. Attractiveness Principle. This archetype states that a reinforcing process of that system is approached.

It hypothesizes that continuing effort will produce diminishing returns as one approaches the limits as one approaches the limits SD Levels of Thinking Events(reactive) Patterns(Adaptive) Structures(Generative) Mental Models(Creative) SD Approach to System Thinking 1 . Problem structuring 2. Causal loop modeling 3. Dynamic modeling 4. Scenario planning and modeling 5. Implementation and organizational learning Systems Dynamics variation of accumulation in stocks within the system If we wish to study the behavior of the banking system, for example, we could look at the what happens to money in the bank. This may be studied by looking at the stock “Money in Bank” and seeing which rates (e. G. Payments, withdrawals, deposits etc. ) affect this stock.

Since anything that leaves one stock ends up in another, we could extend this model and by simulation, raying the rates etc. , see how our system behaves. Dynamic Modeling Steps 1 . Develop a systems map or rich picture 2. Define variable types and construct stock/ flow diagrams 3. Collect detailed information and data 4. Develop a simulation model 5. Simulate steady state/stability conditions 6. Reproduce reference model behavior 7. Validate the model 8. Perform sensitivity analysis 9. Design and analyze policies 10. Develop and test strategies. Some Terms: Stock(level)=state variable(a quantity of something accumulated in various parts of system,changeable over Tim e. G. Venture)/Flow’=input-output=rate of change(differential equation)(the movement of something into or out of a stock:-Result in changes in stocks/levels,-often due to management decisions,-Expo:manufacturing rate,delivery rate) Key Ideas: Inflows>Outflows then stock level rise/ Inflows(xx)->Operational- prototype(equipment)production/ controlled(environment)foreplay/ skilled(operators)typical/ deceleration(aim)realism/technical(focus)usefulness/ engineering limits(unknowns)human denationalizations Levels-Requirements- deals with validation/Design verification-ensuring trace to requirements, consistency, erectness/Module or unit level-check that module meets its design/elongation – checking progressive aggregations of modules/System or Acceptance – against system spec. Verification Method-Testing/Walkout’s,limitations/Analogy/Analysis/ Demonstration.

Blackball Testing-treats a module as a black box I. E. We know nothing about its implementation/ module is simply considered to be a transfer function/test cases derived from specifications (SIRS,SD etc. ). White Box Testing-requires understanding of internal structure of modules/uses branch, path and statement testing/seeks to exercise each choice within modules. Other Types of Testing- Correctness Proofs-formal tests to prove correctness/Stress and Endurance Test- exercise limits of performance and capacity – try to break the software/Seed Testing- seeks to discover proportion of errors we find – introduce x errors and see how many are found.

Verification Planning Considerations-verification method for each requirementNerifIcation strategy – categories of verification etc. /Organization responsible for verification planning and execution/ Disposal of verification results/ Configuration management/Assets requirement for verification/Test and their dependencies/Schedule. Various documents are used to capture the results of planning, and subsequent testing. These include: Verification master Plans/Test Plans/Test Procedures/elongation Plans and Procedures/Test Reports/Others as encourage creative thinking to deepen our understanding of a problem situation/To aid managerial learning/To support critical thinking in a problem context.

ITS is broader than hard or soft system methodologies – it allows us to figure out which methodology suits our context. ITS uses metaphors to identify the class of problem and the major issues. ITS encompasses various systems thinking methodologies. Principles of ITS-Complex systems are difficult or impossible to understand using one model/They should be investigated using a range of metaphors/Organizational issues and problems highlighted by the metaphors can be linked to appropriate systems methodologies to guide application/Different system metaphors and methodologies can be used in a complementary way to address different aspects of the system.

Three phases of ITS-Creativity Phase=Leading to a ‘metaphor picture’/Choice Phase”selection of systems based intervention/lamentation Phase=element selected intervention method. Machine Metaphor-A System-l’s an apparatus with parts that perform defined functions/Does routine, repetitive, pre-determined actions/Seeks rational and efficient means of reaching preset goals and objectives/ Needs to perform simple, well understood tasks/Humans in such a system take on machine-like properties/Environment is stable, closed system view. Advantages of Machine Metaphor-The tasks to be performed are straight forward/Needing repetitive production of a single product/”Human parts” fit into machine/There is a stable environment/Examples include the armed forces, fast food franchises, some technical systems.

Disadvantages of Machine Metaphor- Reduces the adaptability of the organization, making it vulnerable to a changing environment/ requires mindless contributions that are difficult to maintain with mindful parts (dehumidifying or leading to conflict). Organic Metaphor- Recognizes that humans operate better if social and psychological needs are catered for/ Primary aim of system is survival not goal seeking/Systems can be seen as a complex network of elements and relationships that intersect forming highly organized feedback loops/Exist in open environment/Homeostasis – self regulation and repair/System responsive to change ND can reactively cope with complex environment.

Advantages of Organic Metaphor- When there is an open relationship with a complex, changing environment/When there are needs to be satisfied to promote survival/When the environment is complex/Examples include most industrial firms. Disadvantages of Organic Metaphor- Neglects that organizations are socially constructed phenomena/ Emphasizes harmonious relations between the parts – often not the case/Sees change as being generated externally. Neuroscience Metaphor – Emphasis on active learning and control rather than passive adaptability. Let adds “ability to learn” to the cybernetic model that contains:transformation processors information system’s control unit Andean activating unit. /Emphasizes self-enquiry and self criticism implying the possibility of dynamic goal setting. ‘ Encourages creativity. Examples include autonomous work groups, consultancy firms, R&D labs etc. Advantages of Neuroscience Metaphor- Emphasis on active learning and control rather than passive adaptability/ It adds “ability to learn” to the cybernetic model that contains: transformation process, an information system, a control unit, an activating nit/Emphasizes self-enquiry and self-criticism implying the possibility of dynamic consultancy firms, R&D labs etc. Disadvantages of Neuroscience Metaphor- Neglects those parts may have purpose separate to the whole/Results often in recommendations that typically create larger changes than people will tolerate/let neglects that organizations are socially constructed phenomena.