Article
An instance of a design. See also Serial Number. Often used in the context of a “test article” (see also UUT).
Bake Your Noodle
Some of our brains heat up pretty bad when we think too hard.
Because I Can’t Think Of A Reason It Won’t Work
A phrase often uttered as rationale for considering that a CI‘s requirements are (obviously!) met by a prospective design. This one really chaps my hide. Philosophically, it isn’t actually possible to prove the negative. Our job as Engineers is to show why it WILL work…not to challenge other people to show why it WON’T work. ... read more
Big Dog
A person who is so influential (deservedly or otherwise) that their opinions and decisions cannot be ignored. The expression appears to be most commonly used by graduates of Miss’ippi State and Georgia Tech.
Bill It As A Feature
A means of coping with an unfortunate (usually adverse) feature of a design that nevertheless leaves it compliant with the as-written requirements. “Bill” is used in the sense of a splashy advertisement for a show in hopes of distracting attention from the adverse consequences of the situation. See, for example, every other release of a... read more
Bootstrap
In the System Engineering context, to “bootstrap” is to bring order out of chaos through the application of (perhaps) ad-hoc processes. It may, for example, be necessary to strongly tailor requirements derivation practices in order to tease out a customer’s preferences and priorities. Our typical goal is to limit such practices to a project’s “startup... read more
Bottom-up
A developmental method in which existing pieces must be integrated into a single design without regard to top-level objectives. One of two competing System Engineering theories, both of which are wrong. Contrast with Top-down.
Busywork
See helping you track your status.
Characteristic
A feature which, when possessed by the dingus, at least partially qualifies said dingus as being of some particular class (often, but not always, a design). That is, such a feature is considered essential to the “character” of the dingus. In the common usage, a characteristic can be represented in an unstructured manner as text... read more
Coloring as Fast as I Can
A story told by Phil Glynn when we first brought the CBM Assembly Level Qualification Test setup on line:
Conceptual Design
An abstract design, more concrete than Notional, but less concrete than Preliminary. The term is most frequently used to represent the cartoons that made things look like the Development Team had a firm design at SDR. It can, however, be explicitly represented when Technical Characteristics are tensor-valued.
Confuscation
The combination, not always willful, of confusion and obfuscation. See also rat hole and bake your noodle. The proper defense against confuscation is to keep coloring as fast as you can.
Database Design
The process, or the result therefrom, of determining how to store and retrieve information and the relationships between types of data. read more.
Decomposition
A “decomp” is any process of dividing a thing into pieces. To be a valid decomposition, it must be shown that the pieces encompass the entire scope of the “parent”. It is important to assess any proposed decomposition process with respect to this criterion. The details of any given decomposition process depend on the domain... read more
Design Reference Mission (DRM)
A combination of circumstances and operations used as a guideline for development (or selection) of a Configuration Item (CI). The combination might, or might not, contain one or more sequences. DRM’s can vary widely in their complexity. They might (or might not) be used as a source of significant Functional Analysis for development efforts, and... read more
Design Space
An absurdly abstract topological notion, rarely applied in any useful sense. The notion really requires explicit parameterization and evaluation of the technologically relevant features of every feasible conceptual design (which is likely a superset of the required characteristics) relative to the n-dimensional basis formed by the union of all such mutually feasible1 features. Footnotes i.e.,... read more
Developer
The person or organization that develops a product.
Development
The creation of a design for a product, including the generation of data to substantiate the warranty (whether implicit or explicit). read more.
Dingus, The
The thing we’re working on or interested in. The focus of our attention. The widget. The Maltese Falcon. More soberly stated, a collection of one or more elements of hardware, software, and operating procedures intended to exhibit or express one or more features on behalf of an End User during operation.
Disposal
The action taken at the end of a CI’s life. The disposal issue is often ignored during system development, even though doing so can have serious consequences for your children and grand-children (see, for example, Yucca Mountain).
DLL Hell
A predicament in which multiple versions of a Dynamic Linked Library (dll) must be present in order to support multiple linking operations at run-time, couple with an incompletely managed system of defining their applicability by the various pieces of Application Software. The term is actually specific to a certain dominant OS, the concept is broadly applicable.
Domain
In Functional Analysis (mathematics): the set of permissible inputs for a function. In the internet: a cluster of internet addresses, all subordinate to some common node of autonomy, authority, or control.
End User
The abstract concept of the person who uses an item to accomplish some operationally relevant task. Being abstract, this term is uniformly applied to mean both operational users of the product, and some duly recognized organization representing them. The parameterization of the task may, or may not, be directly related to that of the design’s features.... read more
Exogenous
Meaning “to arise from outside”: sourced externally to the subject of discussion.
Feature
A discernible element of form, fit, or function in the dingus. The best features are those dreamed up by the designers that can make our designs better1 than those of our competitors, even if the customers didn’t think of asking for them yet. Contrast that outcome with the idea of Bill It As A Feature, which entails risk... read more
Fit
The precise details of how two or more items interface (whether functionally or physically), inclusive of tolerances. This term is most often used in the static or quasi-static sense, but can be used in a dynamic context. Compare to form and function. See also Form, Fit, and Function.
Form
(1) In legacy hardware usage: the abstract shape of an item absent details of size. “Aspect ratio” is an expression of form, as is “circle”, or “ellipse”. (2) In more recent usage: the features of an item, absent quantification and (sometimes) even parameterization. For example, logical partitioning of algorithm1. Caution is advised in the usage of... read more
Form, Fit, and Function
The three things which, when thoroughly revealed, completely describe a part 1. Note that things like manufacturing processes might not be included in this usage unless they are intrinsic to the End User‘s ability (or willingness) to rely on one or more of these three concepts2. See also, form, fit, and function. Footnotes Which may, or may... read more
Function
1) In mathematics: a relation between a set of inputs and outputs. 2) In System Engineering: A means to impose a particular system state1. To be useful as an Engineering abstraction, a function has to relate to the way the system’s state variables are changed (or, held constant; see also Performance Requirement). The state... read more
Granddaddy
A thing taken as authoritative in its own right, needing neither further justification nor rationale.
Hardhead
A legacy term for Engineers who keep a close eye on reality, and have the backbone to stick with it against all comers…especially those who would reduce the cost and schedule of things they don’t understand.
Hardware
Any artifact 1 comprised of atoms. Just for the sake of starting an endless argument, note that “software“2 and “procedures” are not made up of matter, but the means of their publication can be3. Footnotes Meaning “made by humans”.[↩] Which, in this situation, includes firmware,[↩] aaaaaaand, discuss![↩]
Helping You Track Your Status
Information Technology
A ten-dollar turn of phrase having a catchier sound than “computers and networks and stuff”.
Keep the program sold
A marketing strategy having to do with protecting the life of a program in spite of the many developmental difficulties it may be facing. The strategy may, or may not, be collusively pursued by both contractor and Acquisition Customer. Sadly, this strategy is a necessary part of getting anything useful done in a bureaucratic environment,... read more
Leak Test Pervert
The essential Performance Requirements for the ISS Common Berthing Mechanism (CBM) were: The ability to acquire control authority over the in-coming module, parameterized by the number of (3) and separation between points of contact (90 +/- 30 degrees) between the on-orbit module and the in-coming module at the end of “capture”; The ability to establish... read more
Limit Condition
The extreme verifiable circumstance or value associated with some exogenous parameter used to measure some kind of load on a part, system, or function thereof. Usually, the limit condition is some amount of margin higher than the highest load actually expected during operations, where the margin accounts for uncertainty in derivation of the value. Noting that... read more
Lookoverherelookoverherelookoverhere
A type of smokescreen that may, or may not1, have been repeatedly executed during development of the Common Berthing Mechanism (sometimes referred to as “the debacle” in certain circles of the ISS SE bureaucracy). Footnotes No evidence exists. No conviction can be obtained.[↩]
Margin
Generally, a dimensioned quantity which, when added to some other quantity of the same property, accommodates uncertainties in 1) knowing the value of that other quantity or 2) knowing the value of capability relevant to that other quantity. Sometimes, a margin will be quoted as a dimensionless additive value (when it is “normalized” to some... read more
Measure
(1) As a verb: the act of verifying a quantity by inspection. (2) As a vernacular noun: a seldom-used term referring to a quantifiable property or attribute of a thing. The “thing” itself can be either concrete or abstract. The usage arises from legacy System Engineering practice with respect to requirements, referring to a property... read more
Measure of Constraint
A parameter used to quantify the nature of a constraint (meaning 1).
Measure of Performance
A parameter used to quantify the execution of a function. read more.
Military-Industrial Complex
President Eisenhower coined this term in his 1961 Farewell Address. The basic concept is that the contractors and the uniformed Military forces have figured out that more and better weapons means they both get more power and more money…and they’ll pull any and all strings necessary to make that happen. There have been arguments about... read more
Miss’ippi State
If you can’t pronounce it right, they wouldn’t likely let you in the door, anyway.
Mode
I am aware of no useful definition of “mode” that is universally1 accepted in System Engineering. I have, however, used “mode” to indicate a group of functions, none of which are disabled by some supervisor or executive2. That is, within a single “functional mode”, any given function of that mode can execute according to whatever... read more
Model-based System Engineering (MBSE)
Assuming the definition of model is about right, MBSE simply creates a model of some kind as the specification. What I find fascinating is that the legacy concept of a specification (see, for example, MIL-STD-490) actually meets that description1. This notion is, apparently, lost on the people who have seized on the MBSE buzzword. Most... read more
Newman, Alfred E.
The logo of the now nearly defunct MAD Magazine. Mr. Newman’s picture was understood as a synonym for the magazine’s slogan “What, me worry?”. The relevance to certain System Engineering and management practices should be self-evident.
Non-cognoscenti
Those who are without a technical clue about the problem at hand. Including, but not limited to, non-SME’s.
Non-Conformance (NC)
A situation in which some allocated requirement is determined to not be met by a design (in the case of qualification) or by a S/N or lot (in the case of acceptance).
Notional Design
In the legacy System Engineering processes, the first development phase established a conceptual design for a system. At the end of that phase, the intent was to have identified the characteristic functions of the system, along with other defining non-functional characteristics that distinguish it from other conceptual systems, without having unduly constrained the range of... read more
Objective Requirement
Not, in fact, a requirement at all unless the customer explicitly identifies (in the SoW or T&C) some time, event, or circumstance at which it becomes mandatory, in which case they would more properly be represented by classification of the CI in question. Usually, just an indication of what the customer wishes they could have, if... read more
One-off
The developmental situation in which only a single article is to be produced. Except for very special cases, full-blown developmental and production rigor is very rarely imposed in this situation.
Operating Procedure
Design-specific procedures interactive with a dingus which, when executed in the real world by the End User, makes that dingus do its thingus as intended by the developer.
Operational Analysis
A type of analysis that identifies sequences of action taken by the (possibly prospective) End User. This analysis is typically parameterized based on the effect (possibly merely desired) on circumstances (e.g., conditions, targets, aggressors).
Pearl Harbor File
A collection of concrete evidence, kept on the down-low, that none of the bad things that happened were the fault of the keeper of the file. See also Plan C.
Physical Characteristic
A feature of a design or CI that is directly accessible to one or more of the five classically-defined human senses. Contrast with Function, which is more abstract, generally requiring inference in order to be detected (and, therefore, verified).
Physical Decomposition
A decomposition in the “physical” domain, where the pieces are tangible. To be valid, it must be shown using the laws of physics (e.g., conservation of mass, conservation of energy, continuity of potential difference) that the sum of the parts is exactly equivalent to the whole of the parent. Contrast with Functional Decomposition.
Plan C
The first, best plan (Plan A) is always to do things right, and this is where you should always start. The next best plan (Plan B) is to come as close to right as you can given the real world constraints under which you labor (inclusive of schedule, budget, technology, manufacturing capability, and nincompoops). The... read more
Politics
Activities concerned with achieving control, advancement, or some other goal within (or between) groups of people by way of persuasion, intimidation, compromise or outright supersession. Political methods are the antitheses of Engineering methods, but they’re sometimes necessary in order to get anything done at all.
Production
The act of actually fabricating a deliverable product wherein Engineering gets dragged into the realities of things like cost effectiveness and productivity after the pie-in-the-sky design phase, but before the living hell that is Test 1. Footnotes Don’t get me wrong. I like the test phase, and have always got along well with people who spend... read more
Qualification (Qual)
The process of showing that a design meets the requirements formally allocated to a CI. Contrast with Acceptance, and bear in mind that whereas we qualify the design, we accept the part.
Quality Assurance (QA)
The supervisory process of independently acknowledging the validity of conformance by an S/N or L/N to the allocated requirements as they were asserted by some non-disinterested party. Generally effected by line inspectors of as-built items or as-run formal test, inspection (2), or demonstration.
Rat Hole
A useless distraction or mental contortion not often escaped once entered. The complement of “value added” (the opposite would be “value subtracted”). This refers to place for rats to go down…not an anatomical part of the rat. Many highly respected System Engineers will insist that this entire web site is one.
Real Number
Any number that is not imaginary.
Reconciliation
Two Engineers are charged with making calculations: The first adds 2+2, getting 4.1 (he’s probably loaned out to the Marketing department) The second subtracts 4 -2, getting 1.9 (most likely a nervous stress analyst) Recognizing that there should have been a closer dovetailing of the two answers, management executes one or more of the following:... read more
Research and Development (R&D)
An effort in which an organization or individual speculatively innovates (“research”) and/or designs practical, marketable applications (“develop”).
Research Result
A feature, discovered during research, that can be expressed as a data structure like the one shown in Table 1.
Science Project
A process(2) purporting to be of the Scientific Method, but replacing the stopping criteria with the following Guru Meditation Errors 1: The investigators get bored The investigators retire The investigators find an even more gullible sugar daddy The scam gets discovered Footnotes I once owned an original-version Commodore Amiga. I wish I still had it![↩]
Similarity
The condition in which two (or more) things share a common set of characteristics. The characteristics can be either abstract or concrete. When the characteristic is a term of an equation or logical relation, we can define similarity parameters (e.g., Reynold’s Number, Nusselt Number). When used in support of formal qualification, Similarity is a sub-type... read more
Smokescreen
A low-cost set of activities and data designed to distract the attention of people who cannot tell the difference from the poor performance of the real work not getting done per schedule. Or, occasionally, the marketing of a scheduled activity to cover for the execution of an unscheduled activity that would otherwise have made management... read more
Standup Meeting
If anybody gets tired enough to sit down, you’re doing it wrong.
Subject Matter Expert (SME)
Usually, the person who actually understands the technical material of interest. But not always, and that can cause a whole lot of trouble.
Synthesis
Synthesis is the process of constituting a thing (which may, or may not, be concrete) from individual parts, imposing relationships between them. Contrast with analysis, design and decomposition.
System
Although many definitions have been proposed by various SE groups, I see little to be gained in comparison to standard dictionary1 definitions: 1) A complex unity formed of many often diverse parts subject to a common plan or serving a common purpose; 2) An aggregation or assemblage of objects joined in regular interaction or interdependence:... read more
System Engineering (SE)
Historically, we used SE in reference to two distinct concepts1: Systematic Engineering: repeatable processes for which management 2 has a rational expectation that individual skills and expertise do not dominate their ability to audit a project’s technical status3. This notion derives from the reality that Engineering typically doesn’t own the money it spends, and... read more
Target System
The dingus. Not to be confused with the system of Engineering practices used to develop the Target System, or the system of manufacturing facilities, equipment, and practices that are used to produce it. All three systems are, however, the proper province of a good System Engineer.
Technical Characteristic
A Technical Feature designated as being characteristic of the dingus1. Footnotes Which might, or might not, be abstract.[↩]
Technical Feature
A feature for which a data structure similar to that of Table 1 can be populated. If we put enough technical features together for a single dingus we can start building models. As noted in the table comments, at least two general forms exist1, both of which might be in simultaneous use on the same project. This... read more
Technology
The most basic meaning is “a practical application of knowledge” (often “…scientific knowledge…”), but that definition can be used to mean pretty much anything that anybody wants it to mean. I find it more useful to define the concept as “an abstract use of knowledge outside the context of any specific application”. This definition admits... read more
Terminological Inexactitude
A downright lie (Churchill, speaking to Parliament in 1906). No, no, no…I didn’t mean to say he was the one telling lies, although that might have been the case. I meant to say that he coined the phrase. Either way, not an appropriate System Engineering approach (see also The Four Rules).
The Point of Implementation
An abstract concept denoting the lowest layer of design of general interest to System Engineering during development. At this point in the product structure, no further abstract decomposition (e.g., Functional) is necessary to achieve the intended developmental purpose, so no more Development Requirements remain to be allocated to a design. Any requirements below this layer are written directly... read more
To Be Determined (TBD)
A value (often numeric) that is recognized as necessary, but is not currently known. TBD exists in at least the following forms: TBD: To Be Determined TBS: To Be Supplied TBR: To Be Resolved See TB or Not TB for a discussion of how these concepts should be used during procurement and specification development.
Tolerance
A measure of willingness to permit variation of a feature, including performance. Tolerance is a measure of the capacity to accommodate imperfection. Contrast with uncertainty, which carries no connotation of acceptability.
Top-down
A developmental method in which a single set of overall objectives are decomposed into smaller objectives until individual designs can be accomplished with theoretically perfect confidence of subsequent integration. One of two competing System Engineering theories, both of which are wrong. Contrast with Bottom-up.
Units
A standard for expressing the amount of a property. Units serve as the basic technical discriminator between property values in preference to dimensions for two reasons: 1) Dimensional concepts established by most international conventions address little beyond the physical sciences. 2) The established conventions do not uniformly distinguish between affine concepts and positional concepts1. Don’t... read more
Wirebrushing
In the opinion of the Party of the First Part, the Party of the Second Part has behaved improperly. If the Party of the First Part is superior to the Party of the Second Part (and doesn’t expect to need their help in the future, or just doesn’t care) the Party of the Second Part... read more