In our previous articles, we recommended that the first step of problem-solving is to employ Systems Thinking (ST) and that one must use Systems Engineering (SE) once it is clear that the solution is going to be a ‘system’. This ‘system’ that we are going to be ‘engineering’ as a solution to the problem, is what we will refer to as the ‘System of Interest’ (SoI).
As we begin the SE process, there are going to be a number of contenders for the SoI. Things are going to be fuzzy and ambiguous. Over time, as we persist with the SE process, the SoI is going to slowly take shape and eventually arrive in a final shape and form in which it is going to solve the problem that we started with. Unfortunately, the SoI is not going to last forever, and it will eventually stop solving the problem – either because it is no longer able to solve the problem or because that problem no longer exists! Every SoI has a beginning and an end – a life. This article is about the life of an SoI - a perspective that is foundational to the implementation of a SE approach.
Before moving on, we wish to make another distinction. Let us take a Television (TV) to be our SoI. For purposes of discussion, let us consider a single model and size. The TV will first have to be designed before it can be manufactured. This will be our SoI-design. Using this single design, thousands of TV sets will be manufactured. Each of these TV sets will be an SoI-unit. After a few years, our SoI will be unable to meet the growing expectations of buyers (e.g. size, screen resolution, display technology, connectivity, etc.). When the demand drops, the TV will no longer be manufactured and sold. The SoI-design is now ‘dead’, since it is no longer used to produce any TVs. But each of the SoI-units that have already been manufactured and sold, may still be ‘living’. Some of them may have broken down and been disposed of. Some of them may still be in houses but not being used any more. But some of them may continue to be used for many more years if the buyer has a sentimental value and takes good care of it. Hence, the duration of the life of each SoI-unit will differ. But some day, all SoI-units will ‘die’. This will be the case for any SoI with multiple SoI-units. However, if our SoI were an infrastructure item such as a bridge, there would be only one SoI-design and only one SoI-unit!
Stages of Life
Erik Erickson, a student of Sigmund Freud, divided the lifespan of a human being into eight psychosocial stages:
Infancy (Birth - 18 months)
Early Childhood (18 months – 3 years)
Middle Childhood (3-5 years)
Late Childhood (5-12 years)
Adolescence (12-20 years)
Early Adulthood (20-30 years)
Mature Adulthood (30-65 years)
Old Age (65 years till death)
According to Erik, every person goes through these eight stages over their life span, from the view of the development of personality identity. Dr. Thomas Armstrong, the Executive Director of the American Institute for Learning and Human Development identifies twelve stages of human life, where each stage has a unique gift to give to humanity. Eyal Danon, a life coach, identifies five stages of life, each lasting for 18 years. According to traditional Indian philosophy, each person goes through four stages - student, householder, hermit (or forest dweller), and wandering ascetic (homeless renouncer). An internet search will throw out 100s of different ways in which the lifespan of a human may be divided into several stages, each from a different perspective.
Breaking down the human lifespan into stages helps understand and address the specific needs of humans during each of those stages, from a particular perspective – social, health, philosophy, physical development, developmental psychology, risk perception, behavioral intention, or any other perspective.
Lifecycle Stages of an SoI
Every SoI has a life as well, which we will refer to as its lifecycle. However, unlike a human's lifespan, an engineered system's lifespan will vary drastically – from days or months to decades or even centuries. Therefore, the duration of these stages is not defined – it will depend on the SoI. But from a SE point of view, there is value in dividing the lifecycle of an SoI into stages. It will help us understand what will happen to the SoI in each of these stages and what will be needed by the SoI in each of these stages. INCOSE, in its Systems Engineering Handbook, suggests 6 generic stages of a system lifecycle:
Concept
Development
Production
Utilization
Support
Retirement
Surely, the lifecycle of a system could be divided in many other ways, resulting in different numbers of stages and what we would call each of them. But what’s important is that the entire life of the system is considered and that there is some value that is derived from dividing the lifecycle into stages. For our discussions, we will use INCOSE’s generic 6-stage lifecycle. In each of the stages, the activities that will be performed, the people who will be involved, their competencies that will be essential, the information that will be needed, the tools that will be utilized, and other such factors will vary. Proper planning and preparation for each of these stages is critical for the success of the SoI.
Stage 1: Concept
This is the first stage where the SoI begins to get conceived. In fact, when we started by applying ST and determined that the solution to the problem-situation would be a ‘system’, we have already initiated the concept stage! Here is where there is maximum scope for creativity, to explore a variety of potential options that could solve the problem. We first ensure that we are solving the right problem, by defining it thoroughly and correctly. To do this, we need to first identify and then gather inputs from everyone who will be involved across all stages of the lifecycle. We must also describe how the anticipated solution will be used to solve the problem. Based on these, a number of concepts or potential solutions will typically be generated. In order to compare and shortlist these potential solutions, some analysis will need to be done, along with definitions of relevant measures. Early design activities such as feasibility (or conceptual) design are conducted here.
If your SoI is an electric vehicle (EV) for example, here is where you would explore the overall shape, seating capacity, battery type/capacity, and other such vehicle-level factors.
Stage 2: Development
In the second stage, the short-listed concept(s) from the previous stage are explored further to reach a level of detail based on which the SoI can then be manufactured (or produced). In this stage, samples (or prototypes) may also be built. This is a design-intensive activity, where SE ensures that the right problem that was defined in the previous stage is now being solved the right way in this stage. This is done by carrying out a variety of tests, analyzing the results, and generating other kinds of evidence. The types of design and analysis activities to be done here will depend on the nature of the SoI and all the disciplines that are relevant. They will also require certain expertise, familiarity with tools, availability of information, facilities, and other infrastructure. These must be thought of in advance, and cannot be an afterthought - unless the need came up unexpectedly.
Though the SoI may currently be in the second stage, there may be a need to perform or re-perform some activities belonging to the first stage. In the life of an SoI, many activities are performed iteratively (or repeatedly), in order to converge on some of the details and specifications. This is not because we have not understood the problem well enough or because we do not know how to solve it! Typical engineered systems will need an iterative design approach heavily reliant on disciplinary methods and tools. What SE can help reduce is the overall time for design and development or the number of iterations, by taking a holistic lifecycle approach.
For the EV, here is where one would generate the detailed plans and specifications to build (or buy or reuse) everything that would be needed to put the EV together - not just any EV, but the one that will solve the problem that it is meant to, in the best possible way.
Stage 3: Production
This is the stage where the SoI is produced in the required numbers, based on the details that are generated in the previous stage. Some SoIs may need to be produced in 1000s or 10,000s, some others in 10s, and some others may be just 1! Where will this production happen, where will the raw materials come from, how will they be transported, what skills/resources will be needed for production, what tools/infrastructure/facilities will be needed, and how the produced SoI will reach their final destination, are some of the questions that need to be addressed.
For the EV, here is where you would plan for the location of the assembly plant, establish the assembly line, initiate supply chain processes, and consider all other logistics that will be needed to mass-produce the EV and transport it to dealers in the geographical target area.
Stage 4: Utilization
Once the SoI is ready and in the hands of the intended users, this stage focuses on utilizing the SoI to provide them the expected value in the operational environment. From an SE point of view, this is the stage in which the problem is actually being solved by the SoI. The support infrastructure that will be needed by the SoI must also be considered and planned in advance.
Here is where EV users are driving them to meet their mobility and other transportation needs that they expected the EV to address.
Stage 5: Support
This stage usually goes in parallel with the utilization stage. This stage focuses on the interventions that are needed to sustain the SoI in a state where it can continue to provide value. This could include scheduled interventions like maintenance activities, or unscheduled interventions like repair. Information about the SoI in order to perform these activities must be provided, along with training and facilities for personnel who would be carrying out these activities.
This would include service and repair services provided at the service centres, to make sure that your EV is in good condition.
Stage 6: Retirement
An SoI comes to the end of its useful life when it is no longer able to provide value to its users. What is to be done now, is the focus of this final stage in the lifecycle of the SoI. Most often, this stage receives the least attention, especially if the SoI would be in the utilization stage for a long period of time. However, recent regulations all over the world are forcing engineers to take the activities of the retirement stage seriously, for certain types of SoIs.
At the end of the retirement stage, the SoI (or the particular instance of it, which we have called SoI-unit) will cease to exist or will cease to provide originally intended value to the stakeholders. There will be an intended life of an SoI, but this may vary for each SoI-unit for various reasons. However, what is to be done when any SoI-unit reaches the end of its life, is the focus of this stage. In some cases, some SoI-units may tend to be retained beyond the retirement stage - for sentimental reasons by the user or as a non-functional piece, perhaps in a museum!
When you are done with your EV, you may sell it or scrap it. This stage is about what happens to the EV and its components, including the batteries, after the EV stops being useful to you.
Lifecycle Perspective
A lifecycle perspective is something that differentiates SE from the disciplines that contribute to the engineering of the SoI. Taking an SE approach to engineering an SoI implies that even at the start of the engineering activity in the very first stage of the lifecycle, every stage that the SoI needs to pass through until its end of life is imagined and understood. This is done to minimise the surprises that may arise when the SoI actually reaches those stages. ST is a critical skill that will help take this lifecycle perspective.
Before we end… you may have heard about terms such as “cradle-to-grave” or “womb-to-tomb” to indicate the lifecycle of a system. Just like some organs are donated to others when some person dies, some components of an SoI could also be reused or recycled. The term “cradle-to-cradle” is sometimes used to indicate that if not the entire SoI, some parts of it may continue to live on through the lives of other SoIs. When we say SoI here, it could refer to the SoI-design or to the SoI-unit!
- KS & DH
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Even though it may be difficult, there is an attempt to consider Life cycle cost and try to optimise this. This then requires various stages to be defined.