Snippets (text quotes and extracts from authoritative sources)

A Snippet is a short quote or extract (typically a phrase, a sentence, or at most a few sentences) from an authoritative source document such as a specification, technical manual, or design manual. Throughout this site, content is often related to supporting Snippets and each Snippet page links back to the content pages that reference it! The Snippet and Note concepts are very closely related and they support each other.

The Snippet concept is also at the heart of the Parsing Analysis recipe for UML® and SysML®

Kind Snippet quote/extract Source UML keywords SysML keywords Keywords
INFO Don't judge a book by its cover Wikipedia proverb, Webel Parsing Analysis
INFO clothes maketh the man Wiktionary proverb, Webel Parsing Analysis
INFO This means that: Not all words appearing between guillemets are necessarily keywords, and words appearing in guillemets do not necessarily represent stereotypes. Unified Modeling Language 2.5.1 keyword, Stereotype, guillemets UML, MagicDraw UML
INFO In addition to identifying keywords, guillemets are also used to distinguish the usage of stereotypes. Unified Modeling Language 2.5.1 keyword, Stereotype, guillemets UML, MagicDraw UML
INFO For some kinds of Classifiers, optionally in the right hand corner an icon denoting the kind of Classifier can be displayed. Unified Modeling Language 2.5.1 role, Property, Class, Classifier, Stereotype, Stereotype:icon, icon secondary stereotype, UML, MagicDraw UML
INFO If a role is typed by a classifier other than Class, the name compartment of the part box symbol contains the appropriate keyword (e.g., «component») above the name. Unified Modeling Language 2.5.1 role, Property, Class, Classifier, keyword, Stereotype, Component, «component» secondary stereotype, UML, MagicDraw UML
INFO Stereotypes applied to behaviors may appear on the notation for CallBehaviorAction when invoking those behaviors, as shown in Figure 11-2. OMG Systems Modeling Language (SysML) 1.6 CallBehaviorAction, Behavior, Stereotype secondary stereotype, SysML, Systems Modeling Language, MagicDraw SysML, Cameo Systems Modeler
INFO The stereotype applies to all parameters corresponding to the pins notated by the object node. OMG Systems Modeling Language (SysML) 1.6 Stereotype, Parameter, Pin, ObjectNode, elided Pin notation secondary stereotype, SysML, Systems Modeling Language, MagicDraw SysML, Cameo Systems Modeler
INFO Stereotypes applying to parameters can appear on object nodes in activity diagrams, as shown in Figure 11-7, when the object node notation is used as a shorthand for pins. OMG Systems Modeling Language (SysML) 1.6 Stereotype, keyword, Parameter, ObjectNode, Pin, elided Pin notation SysML Activity Diagram secondary stereotype, SysML, Systems Modeling Language, MagicDraw SysML, Cameo Systems Modeler
INFO As its name indicates, a triple is a set of three entities that codifies a statement about semantic data in the form of subject–predicate–object expressions (e.g., "Bob is 35", or "Bob knows John"). Wikipedia semantic triple, semantic web, RDF, OWL
INFO A semantic triple, or RDF triple or simply triple, is the atomic data entity in the Resource Description Framework (RDF) data model. Wikipedia semantic triple, semantic web, RDF, OWL
INFO The start of the book begins with an eight-year-old orphan girl named Sophie lying in bed ... Wikipedia Webel Parsing Analysis
INFO The giant then says that he will not eat her as he is the Big Friendly Giant, or BFG for short. Wikipedia Webel Parsing Analysis
INFO The giant laughs and explains that most giants do eat human beings (which he pronounces as "human beans") .. Wikipedia Webel Parsing Analysis
INFO When he sets Sophie down, she begins to plead for her life, believing that the giant will eat her. Wikipedia Webel Parsing Analysis
INFO The BFG (short for The Big Friendly Giant) is a 1982 children's book written by British novelist Roald Dahl and illustrated by Quentin Blake. Wikipedia Webel Parsing Analysis
INFO The modern English alphabet is a Latin alphabet consisting of 26 letters, each having an upper- and lower-case form. Wikipedia pangram, Webel Parsing Analysis
INFO ... an English-language pangram — a sentence that contains all of the letters of the English alphabet. Wikipedia pangram, Webel Parsing Analysis
INFO "The quick brown fox jumps over the lazy dog" ... Wikipedia pangram, Webel Parsing Analysis
INFO "The quick brown fox jumps over the lazy dog" is an English-language pangram — a sentence that contains all of the letters of the English alphabet. Wikipedia pangram, Webel Parsing Analysis
INFO This is why we want to work with across variables that have not been overly differentiated. Modelica By Example Modelica, acausal connection
INFO An essential point here is that differentiation is lossy. If we know position, we can easily express velocity. But if we only know velocity, we cannot compute position without knowing an additional integration constant. Modelica By Example Modelica, acausal connection
INFO If we had chosen velocity (the derivative of position with respect to time), then we would have been in the awkward situation of trying to describe the behavior of a spring in terms of velocities, not positions. Modelica By Example Modelica, acausal connection
INFO So, for example, we chose position for translational motion because position is used in describing the behavior of a spring (i.e., Hooke’s law). Modelica By Example Modelica, acausal connection
INFO The second constraint is that the across variable should be the lowest order derivative to appear in any of our constitutive or empirical equations in the domain. Modelica By Example Modelica, acausal connection
INFO The reason for this constraint is that the through variable will be used to formulate generalized conservation equations in our system. As such, it is essential that the through variables be conserved quantities. Modelica By Example Modelica, acausal connection
INFO The first constraint is that the through variable should be the time derivative of some conserved quantity. Modelica By Example Modelica, acausal connection
INFO You may have seen a similar table before with slightly different choices. For example, you will sometimes see velocity (in ) chosen as the across variable for translational motion. The choices above are guided by two constraints. Modelica By Example Modelica, acausal connection
INFO The following table covers four different engineering domains. In each domain, we see the choice of through and across variables that we will be using along with the SI units for those quantities. Modelica By Example Modelica, acausal connection
INFO In this section, we’ll discuss relatively simple engineering domains. These are ones where a connector deals with only one through and one across variable. Conceptually, this means that only one conserved quantity is involved with that connector. Modelica By Example Modelica, acausal connection
INFO As we will see in many of the examples to come, there are many different types of relationships between the through and across variables (Ohm’s law being just one of many). Modelica By Example Modelica, acausal connection
INFO These flows are usually the result of some difference in the across variables across a component model. For example, current flowing through a resistor is in response to a voltage difference across the two sides of the resistor. Modelica By Example Modelica, acausal connection
INFO The second class of variables we will discuss are “through” variables (also called flow variables). Flow variables normally represent the flow of some conserved quantity like mass, momentum, energy, charge, etc. Modelica By Example Modelica, acausal connection
INFO Typical examples of across variables, that we will be discussing shortly, are temperature, voltage and pressure. Differences in these quantities typically lead to dynamic behavior in the system. Modelica By Example Modelica, acausal connection
INFO The first class of variables we will discuss are “across” variables (also called potential or effort variables). Differences in the values of across variables across a component are what trigger components to react. Modelica By Example Modelica, acausal connection
INFO In order to understand one specific class of connector semantics, it is first necessary to understand a bit more about acausal formulations of physical systems. An acausal approach to physical modeling identifies two distinct classes of variables. Modelica By Example Modelica, acausal connection
INFO In thermodynamics, heat is energy in transfer to or from a thermodynamic system, by mechanisms other than thermodynamic work or transfer of matter. Wikipedia heat, energy, energy transfer, thermal transfer, thermodynamics
INFO Some signals in the example reflect physical quantities, but this is not physical interaction in the sense of physical substances with flow rates and potentials ... SysPhS-1.1 SysPhS, humidifier, HVAC&R
INFO A.5 Humidifier: A.5.1 Introduction: This subannex gives a model of a room humidifier as an example of signal flows and state machines. SysPhS-1.1 SysPhS, humidifier, HVAC&R
INFO In many English-speaking countries, however, the most common shape of a handwritten Arabic digit 1 is just a vertical stroke; that is, it lacks the upstroke added in many other cultures. Wikipedia litre, units, scientific unit system, volume, SI unit, SI alternative unit, ISO-80000
INFO In 1990, the International Committee for Weights and Measures stated that it was too early to choose a single symbol for the litre. Wikipedia litre, units, scientific unit system, volume, SI unit, SI alternative unit, ISO-80000, United Kingdom, Ireland, Europe
INFO In the UK and Ireland, as well as the rest of Europe, lowercase l is used with prefixes, though whole litres are often written in full (so, "750 ml" on a wine bottle, but often "1 litre" on a juice carton). Wikipedia litre, units, scientific unit system, volume, SI unit, SI alternative unit, ISO-80000, United Kingdom, Ireland, Europe
INFO In these countries, the symbol L is also used with prefixes, as in mL and μL, instead of the traditional ml and μl used in Europe. Wikipedia litre, units, scientific unit system, volume, SI unit, SI alternative unit, ISO-80000, Canada, Australia, United States
INFO The United States National Institute of Standards and Technology now recommends the use of the uppercase letter L, a practice that is also widely followed in Canada and Australia. Wikipedia litre, units, scientific unit system, volume, SI unit, SI alternative unit, ISO-80000, Canada, Australia, United States
INFO Therefore, the digit "1" may easily be confused with the letter "l". In some computer typefaces, the two characters are barely distinguishable. As a result, L (uppercase letter L) was adopted by the CIPM as an alternative symbol for litre in 1979. Wikipedia litre, units, scientific unit system, volume, SI unit, SI alternative unit, ISO-80000
INFO Originally, the only symbol for the litre was l (lowercase letter L), following the SI convention that only those unit symbols that abbreviate the name of a person start with a capital letter. Wikipedia litre, units, scientific unit system, volume, SI unit, SI alternative unit, ISO-80000
INFO The litre (British English spelling) or liter (American English spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. It is equal to 1 cubic decimetre (dm^3), 1000 cubic centimetres (cm^3) or 0.001 cubic metre (m^3). Wikipedia litre, units, scientific unit system, volume
INFO The enthalpy of vaporization of Water at 100 deg C = 2257 (J/g) Wikipedia volumetric heat capacity, thermodynamics, joule, enthalpy of vaporisation, latent heat of vaporisation, heat of evaporation, enthalpy, evaporation
INFO The enthalpy of vaporization is often quoted for the normal boiling temperature of the substance. Wikipedia volumetric heat capacity, thermodynamics, joule, enthalpy of vaporisation, latent heat of vaporisation, heat of evaporation, enthalpy, evaporation
INFO The enthalpy of vaporization is a function of the pressure at which that transformation takes place. Wikipedia volumetric heat capacity, thermodynamics, joule, enthalpy of vaporisation, latent heat of vaporisation, heat of evaporation, enthalpy, evaporation
INFO The enthalpy of vaporization (symbol ∆Hvap), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy (enthalpy) that must be added to a liquid substance to transform a quantity of that substance into a gas. Wikipedia volumetric heat capacity, thermodynamics, joule, enthalpy of vaporisation, latent heat of vaporisation, heat of evaporation, enthalpy, evaporation
INFO The volumetric heat capacity can also be expressed as the specific heat capacity (heat capacity per unit of mass, in J/K/kg) times the density of the substance (in kg/L, or g/mL). Wikipedia volumetric heat capacity, thermodynamics, joule, kelvin, water, celsius
INFO The SI unit of volumetric heat capacity is joule per kelvin per cubic meter, J/K/m3 or J/(K·m3). Wikipedia volumetric heat capacity, thermodynamics, joule, kelvin, water, celsius
INFO Informally, it is the amount of energy that must be added, in the form of heat, to one unit of volume of the material in order to cause an increase of one unit in its temperature. Wikipedia volumetric heat capacity, thermodynamics, joule, kelvin, water, celsius
INFO The volumetric heat capacity of a material is the heat capacity of a sample of the substance divided by the volume of the sample. Wikipedia volumetric heat capacity, thermodynamics, joule, kelvin, water, celsius
INFO Isobaric volumetric heat capacity C(P,v) J⋅cm−3⋅K−1 of liquid Water at 100 °C = 4.2160 Wikipedia volumetric heat capacity, thermodynamics, joule, kelvin, water, celsius
INFO Isobaric volumetric heat capacity C(P,v) J⋅cm−3⋅K−1 of liquid Water at 25 °C = 4.1796 Wikipedia volumetric heat capacity, thermodynamics, joule, kelvin, water, celsius
INFO The blocks used in these diagrams are introduced in Subannex A.5.4. SysPhS-1.1 SysPhS, humidifier, HVAC&R
INFO The internal structure of VaporGenerationPlant uses blocks Heating and Evaporation, which have internal structures depicted in Figure 70 and Figure 71, respectively. SysPhS-1.1 SysPhS, humidifier, HVAC&R
INFO The internal structure of Humidifier in Figure 68 uses a block VaporGenerationPlant, which has an internal structure shown in Figure 69. SysPhS-1.1 SysPhS, humidifier, HVAC&R
INFO The internal structure of HumidifiedRoom depicted in Figure 66 uses a block RelativeHumidity, which has an internal structure depicted in Figure 67. SysPhS-1.1 SysPhS, humidifier, HVAC&R
INFO The internal structure of the block HumidifierSystem shown in Figure 65 uses the blocks HumidifiedRoom and Humidifier. These two blocks have their own internal structures. SysPhS-1.1 SysPhS, humidifier, HVAC&R
INFO A.5.3 Internal structure: Figure 65 through Figure 71 show the internal structure of the total humidifier system and its components through seven nested internal block diagrams. SysPhS-1.1 SysPhS, humidifier, HVAC&R
INFO The humidifier uses information about the room’s humidity level to determine how much vapor to input to the room. The humidifier includes a water tank, a heater controller, and a vapor generation plant. SysPhS-1.1 SysPhS, humidifier, HVAC&R
INFO A.5.2 System being modeled: The total humidifier system has two main components: the humidified room and the humidifier, see Figure 64. SysPhS-1.1 SysPhS, humidifier, HVAC&R
NOTATION The compartment name is otherwise the same as it would appear on the type on a block definition diagram. OMG Systems Modeling Language (SysML) 1.6 compartment property compartment, SysML Internal Block Diagram, IBD :features compartments, :values compartment, :parts compartment, :properties compartment, :references compartment, :flow properties compartment, :operations compartment
NOTATION The label of any compartment shown on the property box that displays contents belonging to the type of the property is shown with a colon character (“:”) preceding the compartment label. OMG Systems Modeling Language (SysML) 1.6 compartment property compartment, SysML Internal Block Diagram, IBD :features compartments, :values compartment, :parts compartment, :properties compartment, :references compartment, :flow properties compartment, :operations compartment
INFO In nonideal fluid dynamics, the Hagen–Poiseuille equation ... is a physical law that gives the pressure drop in an incompressible and Newtonian fluid in laminar flow flowing through a long cylindrical pipe of constant cross section. Wikipedia Hagen–Poiseuille equation, fluid flow, hydraulics
INFO Figure 62 and Figure 63 show the parametric diagrams of the tank and the pipe, respectively. SysPhS-1.1 Constraint constraint parameter, ConstraintBlock, BindingConnector, SysML Parametric Diagram SysPhS
INFO Binding connectors link constraint parameters to simulation variables and constants, indicating their values must be the same. SysPhS-1.1 Constraint constraint parameter, ConstraintBlock, BindingConnector, SysML Parametric Diagram SysPhS
INFO Component parametric diagrams show properties typed by constraint blocks (constraint properties), as well as component and port simulation variables and constants. SysPhS-1.1 Constraint constraint parameter, ConstraintBlock, BindingConnector, SysML Parametric Diagram SysPhS
INFO Equations in constraint blocks are applied to components using binding connectors in component parametric diagrams. SysPhS-1.1 Constraint constraint parameter, ConstraintBlock, BindingConnector, SysML Parametric Diagram SysPhS
INFO Also, the fluid flow in the tank, fluidFlow, is related to the change in the fluid height level fluidHeight over time and the cross-sectional surface area of the tank, surfaceArea. SysPhS-1.1 Constraint constraint parameter, ConstraintBlock SysPhS, pressure, hydraulics, fluid flow
INFO The tank constraints specify that the pressure in the tank, pressure depends on the height of the fluid level in the tank, fluidHeight, as well as properties of the fluid, fluidDensity. SysPhS-1.1 Constraint constraint parameter, ConstraintBlock SysPhS, pressure, hydraulics, fluid flow
INFO The sum of the fluid flow rates going through the two pipe openings is zero (the fluid is assumed to be incompressible). SysPhS-1.1 Constraint constraint parameter, ConstraintBlock SysPhS, pressure, hydraulics, fluid flow
INFO The magnitude of fluid flow rate through the pipe fluidFlow is the same as the magnitude of flow rates opening1FluidFlow and opening2FluidFlow going through the pipe’s openings, though the values differ in sign. SysPhS-1.1 Constraint constraint parameter, ConstraintBlock SysPhS, pressure, hydraulics, fluid flow
INFO The fluid flow rate through the pipe, fluidFlow, is proportional to the pressure difference by the constant resistance, which depends on the geometric properties of the pipe as well as fluidic properties. SysPhS-1.1 Constraint constraint parameter, ConstraintBlock SysPhS, pressure, hydraulics, fluid flow
INFO The pipe constraints specify that the pressure pressureDiff across it is equal to the difference of fluid pressures opening1Pressure and opening2Pressure at each end of the pipe. SysPhS-1.1 Constraint constraint parameter, ConstraintBlock SysPhS, pressure, hydraulics, fluid flow
INFO In this example, constraint blocks PipeConstraint and TankConstraint define parameters and equations for pipes and tanks, respectively, as shown in Figure 61. SysPhS-1.1 Constraint constraint parameter, ConstraintBlock
INFO Equations define mathematical relationships between the values of numeric variables. Equations in SysML, are constraints in constraint blocks that use properties of the blocks (parameters) as variables. SysPhS-1.1 Constraint constraint parameter, ConstraintBlock
INFO An alternative for specifying initial values of part properties in the ConnectedTanks is to specialize it and redefine the part properties with default values for various configurations ... SysPhS-1.1 Property::redefinedProperty SysPhS
INFO SysML initial values specify property values for components used in internal block diagrams. Figure 59 shows initial values for fluid density, gravity, tank surface area, pipe radius, pipe length, and dynamic viscosity of the fluid ... SysPhS-1.1 initial values, context-specific values, initialValues compartment SysPhS, hydraulics
INFO Item flows on connectors indicate fluid passes through the ports and between the parts. The diagram connects a tank to each end of a pipe. SysPhS-1.1 Connector SysML Internal Block Diagram, ItemFlow SysPhS, hydraulics
INFO Part properties, typed by blocks ... represent components in this system. They are connected to each other through ports, which represent openings in the tanks and pipe ... SysPhS-1.1 Connector, Port part property, Block, "standard" Port SysPhS, hydraulics
INFO Figure 59 shows the internal structure of a ConnectedTanks block. SysPhS-1.1 SysML Internal Block Diagram SysPhS, hydraulics
INFO Each type of component has its own behaviors, defined as constraints ... SysPhS-1.1 Constraint ConstraintBlock SysPhS, hydraulics
INFO Tanks and pipes have openings for fluid to pass through, one for tanks and two for pipes. The openings are represented by ports of type VolumeFlowElement, from the physical interaction library .. SysPhS-1.1 SysPhS, hydraulics
INFO Figure 60 shows block definitions for components of ConnectedTanks in Figure 59. SysPhS-1.1 SysPhS, hydraulics
INFO A.4.1 Introduction: This subannex gives a model of a simple hydraulic system as an example of physical interaction (fluid flow). It does not include any signal flows SysPhS-1.1 SysPhS, hydraulics, fluid flow, physical interaction
INFO A.4.2 System being modeled: The hydraulic system has three components: two fluid reservoir tanks and a pipe for connecting these tanks, see Figure 58. SysPhS-1.1 SysPhS, hydraulics
INFO Figure 52 through Figure 57 show parametric diagrams for the source, amplifier, high-pass fil[t]er, low-pass filter, mixer, and sink, respectively. SysPhS-1.1 Constraint ConstraintBlock, constraint parameter, BindingConnector, SysML Parametric Diagram, constraint property, MD:ConstraintProperty SysPhS, signal processing
INFO Binding connectors link constraint parameters to simulation variables and constants, indicating their values must be the same. SysPhS-1.1 Constraint ConstraintBlock, constraint parameter, BindingConnector, SysML Parametric Diagram, constraint property, MD:ConstraintProperty SysPhS, signal processing
INFO Component parametric diagrams show properties typed by constraint blocks (constraint properties), as well as component and port simulation variables and constants. SysPhS-1.1 Constraint ConstraintBlock, constraint parameter, BindingConnector, SysML Parametric Diagram, constraint property, MD:ConstraintProperty SysPhS, signal processing
INFO Equations in constraint blocks are applied to components using binding connectors in component parametric diagrams. SysPhS-1.1 Constraint ConstraintBlock, constraint parameter, BindingConnector, SysML Parametric Diagram SysPhS, signal processing
INFO The source constraint specifies a sine wave signal with the parameter amp as its amplitude. The sink constraint displays (scopes) the output signal from the signal processor. SysPhS-1.1 Constraint ConstraintBlock, constraint parameter SysPhS, signal processing
INFO The mixer constraint specifies the relationship between its one output and the two inputs that come from the low-pass and high-pass filters. The constraint defines the output to be the average of the inputs. SysPhS-1.1 Constraint ConstraintBlock, constraint parameter SysPhS, signal processing, mixer
INFO The amplifier changes the signal strength by a factor gain, the low-pass filter eliminates the high-frequency components of the incoming signal, and the high-pass filter eliminates the low-frequency components of the signal. SysPhS-1.1 Constraint ConstraintBlock, constraint parameter SysPhS, signal processing, amplifier, high-pass filter, low-pass filter
INFO The amplifier, low-pass fil[t]er, and high-pass filter constraints show the input-output relationship of these components as the signal passes through them. SysPhS-1.1 Constraint ConstraintBlock, constraint parameter SysPhS, signal processing, amplifier, high-pass filter, low-pass filter
INFO In this example, a constraint block BinarySignalComponentConstraint defines the parameters for one input (ip) and one output (op), common to amplifiers, low-pass filters, and high-pass filters, as shown in Figure 51. SysPhS-1.1 Constraint ConstraintBlock, constraint parameter SysPhS, signal processing, amplifier, high-pass filter, low-pass filter
INFO Equations define mathematical relationships between the values of numeric variables. Equations in SysML, are constraints in constraint blocks that use properties of the blocks (parameters) as variables. SysPhS-1.1 Constraint ConstraintBlock, constraint parameter SysPhS, signal processing