They do certainly give very strange and new-fangled names to diseases.

-- Plato, The Republic

 

Indexed Glossary1

Aggregate Model 24
A model at low resolution or high abstraction.

Aggregation 13, 24
Composition of a collection of HREs into a single LRE.

Aggregation-disaggregation 5, 11 , 32, 44, 49, 57, 104
An MRM approach in which representation levels are transitioned.

Attribute 19
A property of an entity, which can be used to refer to the entity and manipulate its behavior.

Attribute Dependency Graph 4, 16, 57 , 104
A graph with attributes as nodes and dependencies among attributes as arcs.

Behavior of an Entity 22
The sequence of states for a particular entity.

Behavior of a Model 22
The sequence of states of a model.

Certain Interaction 84 , 89
An interaction whose outcome is predictable.

Chain Disaggregation 13, 32 , 50, 119
Forcible disaggregation of many entities because of LRE-HRE interactions.

Compatible Time-steps 25 , 29, 40, 159, 117
If multiple entities never violate any assumptions made by one other during any time-step, they execute at compatible time-steps .

Concurrent Interactions 4, 22 , 29, 47, 81
Interactions that occur at overlapping times in the simulation.

Concurrent Representations 1, 24 , 41
Representations of different simulation entities of the same object or process that execute jointly and allow interaction at all representation levels.

Consistency Cost 5, 16, 44, 105 , 107
Cost of maintaining consistency among jointly-executing models.

Consistency Enforcer 4, 16, 45 , 56, 70, 104
Consists of an Attribute Dependency Graph and appropriate mapping functions for maintaining internal consistency in a Multiple Representation Entity.

Consistency Maintenance 1, 25
Correlating the multiple entity states for the same object or process so that relationships among attributes hold.

Cost-effectiveness (R3) 5 , 28, 105
Simulation and consistency costs should be low.

Cross-level Interactions 34, 43, 51
Interactions whose sender and receiver are at different representation levels.

Cumulative Dependencies 56, 60 , 63
Attribute dependencies wherein the value of a single attribute depends jointly on the value of many other attributes.

Dependency 22
A static relationship between two attributes.

Dependent Interactions 4, 23 , 38, 41, 81
Interactions whose effects are dependent on one another.

Disaggregate Model 24
A model at high resolution or low abstraction.

Disaggregation 13, 24
Decomposition of an LRE into its constituent HREs.

Distributive Dependencies 56, 60 , 64
Attribute dependencies wherein the value of a single attribute influences the value of many other attributes jointly.

Effective Joint Execution 1, 16, 27 , 41, 103
The joint execution of multiple models that satisfies the requirements of multi-representation interaction, multi-representation consistency and cost-effectiveness.

Effects of an Interaction 20
The changes caused in the representations of the sender and receivers because of the interaction.

Entity 2, 19
A description of an object or process in a simulation.

Entity Representation 19
A collection of the attributes of one entity described using the notation of data structures.

Environment of a Model 19
Objects and processes external to a model.

Executing a Model 21
Simulating the objects and processes that are part of a phenomenon.

Execution of a Multi-model 2
The joint execution of multiple models.

Fundamental Observations 3, 31
Observations that relate the causes of problems in jointly-executing models to a failure in maintaining consistency among the model representations.

Ghosting 41
With multiple models, executing only one model and reflecting changes from that model to other models.

Guidelines for Designers of Multi-models 5, 96
With multiple models, executing only one model and reflecting changes from that model to other models.

Hierarchical Models 60
Models that bear a relationship of being the composition-decomposition or abstraction-refinement of one another.

High Resolution Entity (HRE) 12, 24 , 32, 50
An entity at a low level of abstraction, or high decomposition.

Independent Interactions 23 , 86
Interactions whose effects are the same whether they occur in isolation or concurrently.

Interaction 3, 20, 22 , 76
The means by which entities exchange information or influence one another.

Interaction Dependencies 56, 61
Attribute dependencies that denote the effects of interactions.

Interaction Resolver 4, 16, 45 , 89
Resolves the effects of concurrent interactions on a Multiple Representation Entity by means of policies based on semantic characteristics of interactions.

Internal Consistency with an MRE 41
Attribute dependencies that denote the effects of interactions.

Joint Execution of Multiple Models 2, 24
Execution of multiple models at overlapping times, possibly with the exchange of information among the models.

Low Resolution Entity (LRE) 12, 24 , 32, 50
An entity at a high level of abstraction, or high composition.

Mapping Consistency 5 , 47
When entity properties common to different models are translated such that repeated translations in a given period do not cause abnormal behavior in the entity during that period, the models exhibit mapping consistency.

Mapping Inconsistency 32 , 44, 49, 119
When repeated translations among attributes cause intolerable discontinuities in the behavior of different models, the models exhibit mapping inconsistency.

Mapping Functions 4, 16, 25 , 29, 41, 65, 159, 104
Methods used to correlate the multiple representations of the same object or process.

Model 2, 21
An abstraction of some phenomenon that incorporates the behavior of objects and processes participating in that phenomenon.

Modeling 2, 19
A method to study real-life phenomena.

Modeling Dependencies 56, 60, 61
Attribute dependencies inherent in the nature of the object or process being modeled.

Multi-model 2, 24, 24
For some phenomenon, the union of multiple models that may differ in execution and representation.

Multiple Representation Entity (MRE) 3, 16, 41 , 54, 56
A conceptual entity that can interact at multiple representation levels concurrently by maintaining attributes at different representation levels.

Multi-representation Consistency (R2) 5 , 28, 104
Jointly-executing models must be related and consistent with one another.

Multi-representation Interaction (R1) 5 , 27, 44, 104
Entities in each model may initiate and receive interactions that may be concurrent and dependent.

Multi-representation Modeling (MRM) 2, 19, 24 , 159
The joint execution of multiple models.

Network Flooding 33 , 51, 119
High consumption of network resources because of a large number of messages.

Receiver of an Interaction 20
The entity that receives an interaction.

Relationship between Attributes 19
Indicates that if the value of one attribute changes, the value of the other is likely to change.

Representation 2, 19 , 116
A collection of the objects and processes participating in a phenomenon described using some rigorous notation.

Representation Level 24
The conceptual context in which a model executes.

Request Interaction 84 , 86, 88
An interaction concerned with actions that may take place in the future.

Resolving Concurrent Interactions 23 , 36, 47, 54, 85, 88, 159, 117
Computing the effects of concurrent, possibly dependent, interactions.

Resolution 24
A representation level in a hierarchical model.

Resolution Level 24
Resolution.

Response Interaction 84 , 86, 88
An interaction concerned with actions that have taken place in the past.

Reversible Mapping Functions 25 , 47, 48, 68
Mapping functions that return the original attribute when composed.

Selective Viewing 5, 11 , 44, 49, 57, 104
An MRM approach in which the most detailed model is simulated at all times.

Sender of an Interaction 20
The entity that initiates an interaction.

Simulation 2, 21
A method to execute a model, usually on a computer with some combination of executing code, control/display interface hardware and interfaces to real-world equipment.

Simulation Cost 5, 16, 44, 105 , 108
Cost of simulating jointly-executing models.

Taxonomy of Interactions 4, 16, 83
A classification of interactions according to semantic characteristics of interactions.

Temporal Consistency 5 , 45
When multiple entities have consistent views of another entity at overlapping simulation times, the entities exhibit temporal consistency.

Temporal Inconsistency 53, 119
When multiple entities have differing views of an entity at overlapping simulation times, they exhibit temporal inconsistency.

Thrashing 33 , 50, 119
Repeated transitions by an entity because it transitions representation levels frequently.

Time-step 21 , 38
The duration of time between two consecutive observation times of a model.

Transition Latency 33 , 50, 119
Delay encountered when performing an aggregation or disaggregation.

Uncertain Interaction 84 , 89
An interaction whose outcome is unpredictable.

UNIFY 4 , 3, 27, 31, 41, 159, 116
A framework for effective MRM.


1. In the spirit of UNIFY , this chapter is a glossary as well as an index. The numbers to the right of each term denote pages in which the term is discussed. The bold number refers to the page in which we define the term. Below every index entry is an informal definition for the term.