Systems Engineering
Systems Engineering is an interdisciplinary field of engineering that focuses on how complex engineering projects should be designed and managed over the life cycle of the project. Issues such as logistics, the coordination of different teams, and automatic control of machinery become more difficult when dealing with large, complex projects. Systems engineering deals with work-processes and tools to handle such projects, and it overlaps with both technical and human-centered disciplines such as control engineering, industrial engineering, organizational studies, and project management.
The GVCS qualifies as a "complex engineering project", and can therefore benefit from applying this engineering discipline/specialty. This page is lists some of the basics of Systems Engineering as it can be applied to the GVCS, and will point to further references for people who want more depth on the subject.
Contents
Systems Engineering Tools
Over the years a number of tools have been developed to aid in designing complex systems.
Requirements Analysis
A system as a whole has a statement of what we want it to do. This is in the form of goals, values, mission description, performance requirements and such. It also needs ways to measure how good a given design is. These can be things like "minimum cost", "minimum waste output", and "maximum efficiency". These statements and measures are often in verbal form. Requirements Analysis is the process of putting them in numerical form, breaking them down to more detail, and assigning them to functions who will perform them. The assignment ensures that somewhere in the system the top level goals are met.
At the most detailed level a subset of the requirements are assigned to a single function box. This now becomes the conditions that a specific engineering design needs to meet.
Input/Output Model
This can be visualized as a spreadsheet with various machines in the GVCS as columns, and inputs and outputs as rows. Each machine requires inputs such as steel, lubricants, assembly labor, fuel, etc. It also produces some kind of output. The purpose of a model is to see if your system as a whole has closure and balance. In other words, are all the inputs matched by outputs? Are there missing machine types identified by missing inputs? Is the size or quantity of a particular machine in the kit the correct size/productivity? Will the system as a whole produce a surplus, and if so how much? These are really all questions of accounting. Rather than counting everything in money, this type of spreadsheet does the accounting of each type of input/output/resource/supply separately as categories. Note that human labor for manufacturing, assembly, maintenance, and operation is one of the input types.
Functional Block Diagrams
A complex system is too hard to design as a whole. By breaking it down into smaller components, which is called Functional Analysis you reach a level that can be designed in practice. Functional Block Diagrams are a way to display the component parts of a system from a functional perspective. In other words, what does it do? It also shows the flows among the parts of the system with each other, and also with the external environment. In other words, how does it interact? Flows can contain any sort of item, including information, matter, energy, labor, etc, or a combination thereof. Please see the linked page for more detail.
Trade Studies
A given function can be satisfied by one or more designs, which are evaluated and optimized according to the goals and requirements of the project. Choosing among alternatives and optimizing a given alternative are formally done with Trade Studies. Different designs are objectively compared using a set of numerical measures, i.e. a scoring system. The measures should be derived directly from the project goals and requirements and applied consistently across the whole system. A single design is optimized by varying a feature, such as power output, and then using the same scoring system to find the best value.
Connecting Block Diagrams and Input/Output Models
Functional analysis is a continuing task done incrementally, rather than done once with a static product. The block diagrams are a way to record and communicate the structure of a system. A model, such as an Input/Output Model lets you actively see how a change in any one component, such as a new design, impacts the system as a whole. By summing the flows of the component functions in a model spreadsheet (or other computer model) you can immediately find changes to the rest of the system components and the totals for the entire system.
Using the same numbering system and structure for the diagrams and models maintains the relationship between them. They are both representing the same system, just different aspects.
Design Variables
The Earth is not a uniform location. Thus the design of the system must take into account the following types of variables by offering different components or quantities in response:
- Available energy sources
- Available money and skills of people
- Available water sources
- Cost and availability of land
- External sources of materials, parts, tools, and machines
- Physical environment for growing food
- Physical environment for housing
If possible a progressive sequence should be designed into the system. This would define minimal "starter sets", and then optional add-ons, growth paths, second generation more specialized machines built using the first generation, etc. Depending on circumstances, people can then follow a growth path from some starting point to a desired end goal without needing to do it all at once.
Glossary
These are technical engineering terms as used in the Systems Engineering field, which are not the same as general common use of the same words.
Architecture - Fundamental concepts or properties of a system in its environment embodied in its elements, relationships, and in the principles of its design and evolution.
Concern - Interest in a system relevant to one or more of its stakeholders. It pertains to any influence on a system in its environment including: developmental, technological, business, operational, organizational, political, economic, legal, regulatory, ecological, and social influences.
Environment - Context determining the setting and circumstances of all influences upon a system from outside the defined system boundary.
System - The combination of elements that function together to produce the capability to meet a need, but which do not do so as separate elements. The elements include all hardware, software, equipment, facilities, personnel, policies, processes, documents, and procedures needed for this purpose. A system as a whole exhibits qualities, properties, characteristics, functions, behavior, and performance. The value added by a system as a whole, beyond that contributed by its elements, is created by the relationship of its parts, in other words how they are interconnected.
References
Systems Engineering as a field has been developed over a number of years. Thus there are a number of useful references on the subject. This is only a partial list to get started:
- 'ISO/IEC 15288 - "Systems and software engineering - System Life Cycle Processes" - 2nd Edition, Feb 1, 2008. This is an international standard to provide a common process framework covering the life cycle of man-made systems. The purpose of the standard is to provide a common way to communicate among various people involved with a project. This is similar to having a common language for text, or common symbols for mechanical or electrical drawings.
