90 likes | 186 Views
The System Entity Structure: Using Simulation to Search and Optimize. System Entity Structure Examples Model Base Organization and Synthesis System Entity Structure for Optimal crew size Worker interference Paper and Pencil Analysis. System Entity Structure.
E N D
The System Entity Structure: Using Simulation to Search and Optimize • System Entity Structure • Examples • Model Base Organization and Synthesis • System Entity Structure for Optimal crew size • Worker interference • Paper and Pencil Analysis
System Entity Structure • System Entity Structure (SES) represents a family of hierarchical DEVS models • Particular members of the family are generated by process called pruning to generate a pruned entity structure (PES) • A hierarchical DEVS model ready to execute is obtained by transforming a PES, i.e., accessing components in a repository and coupling them together according to the PES specification.
System Entity Structure Axioms • SES is represented as a labeled tree with attached attributes that satisfies the following axioms: • alternating entity/aspect or entity/specialization: • Each node has a mode that is either entity/aspect or entity/specialization • such that a node and its successors are always opposite modes; the mode of the root is entity. • Coupling is associated with aspects • uniformity: • Any two nodes with the same names have identical attached variable types and isomorphic sub-trees. • strict hierarchy: • No label appears more than once down any path of the tree. • valid brothers • No two brothers have the same label. • attached variables: • No two variable types attached to the same item have the same name.
aspect entity specialization
carriage specialization contents specialization freight cargo SES Example elevator physical decomposition motion specialization floors contents escalator pas- senger lift Rule – if select freight from carriage spec then select lift from motion spec and select cargo from contents spec people Rule – if select passenger from carriage spec then select people from contents spec
city roadNet roadSeg line traffic Genr (G) traffic Light (L) road Sched (S) seg S S S G G G L L L step event Seg Seg Seg Seg Seg Seg Seg Seg Seg ... ... ... roadNet roadSeg SES Multiplicities city multiple aspect roadNet multiple entity
System Entity Structure Inheritancee.g., Mapping into XML specialized entities inherit their parents subtriee vehicle aluminum.airplane.vehicle - density = low - strength = medium speed = high material composition decomposition - density - strength transportation class - speed decomposition motor transmission propulsion aluminum car ship steel airplane - buoy ancy - density = low - strength = medium - speed = high motor transmission wing.propulsion wood wings wheels XML: <object> aluminum.airplane.vehicle <density> low <strength> medium <speed> high <madeof> motor transmission wing.propulsion Rule: if select airplane from transportation then select aluminum from material composition and wings from propulsion Note: buoyancy field is not present
Repository of DEVS components SES/Model Base: Synthesize new models from reusable DEVS components SES Develop a System Entity Structure to organize the Repository PES transforming pruning hierarchical DEVS model