ESI 6529 DIGITAL SIMULATION TECHNIQUES

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ESI 6529 DIGITAL SIMULATION TECHNIQUES

• Lecture 8

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Additional Modeling Features

• Additional Blocks and Elements provide the
  ability to Form groups of entities
• Select from parallel queues
• Select from parallel resources
• Conduct conditional searches
• Manipulate queues
• Preempt entities utilizing resources
• Synchronize events
• Conduct file input / output

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• Permanent Entity Sets
• The COMBINE and DUPLICATE Blocks
• The COMBINE block can be used to combine Qty
  entities from the preceding queue to form a
  permanent new entity with attribute values
  specified by the Save Criterion. The COMBINE
  block is summarized below.COMBINE, Match
  Expression Quantity to combine,
• Save CriterionExamples COMBINE 6,
  FIRSTCOMBINE, Parttype 10, PRODUCT

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• The DUPLICATE block can be used to create
  Quantity duplicates of the arriving entity, and
  send them to the Labeled Block. It also assigns
  the attribute value of the original entity to
  each duplicate. The DUPLICATE block is summarized
  below.DUPLICATE Quantity to Duplicate,
• Duplicate destination repeatsExamplesDUPL
  ICATE 5DUPLICATE 1, SubAssembA 3,
  SubAssembB
• DUPLICATE 1, L2NEXT(L1)
• BRANCH, 2 ALWAYS, L1 ALWAYS, L2

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• Temporary Entity Sets
• The GROUP and SPLIT blocks
• The GROUP block can be used to group entities
  from the preceding queue into one temporary
  entity with attribute values specified by the
  Save Criterion. The GROUP block is summarized
  below.GROUP, Match Expression
• Quantity to group, Save CriterionExamples
  GROUP Group Size, SUMGROUP, Parttype 3

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• The SPLIT block can be used to split a temporary
  entity into its original individual entities. It
  assigns specified attribute values to each
  individual entity. The temporary group entity is
  destroyed.SPLIT Attribute, repeatsExamples
  SPLIT Marktime, M

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• Temporary Entity Sets
• The PICKUP and DROPOFF blocks
• The PICKUP block can be used to remove Qty
  consecutive entities from QueueID, starting at
  position Rank and add these entities to the
  current entity group.PICKUP QueueID, Rank,
  QtyThe DROPOFF block can be used to remove
  Qty consecutive entities from the current entity
  group, starting with entity number Rank, and send
  them to the labeled block. It also assigns
  specified attribute values to each
  entity.DROPOFF, Rank, Qty Dropoff location,
  attributes

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• Matching Entities
• The MATCH Block
• The MATCH block holds entities in preceding
  queues, labeled QueueLabel, until there is an
  entity in each queue with matching values of
  Attribute. It sends each entity to its
  corresponding DestLabel. If no label is given, it
  destroys the entity. The MATCH block is
  summarized below.MATCH, Match attribute
  QueueLabel, DestLabel repeatsExamplePatient
  s QUEUE, PatQ DETACHRecords QUEUE,
  RecQDETACH MATCH, ID Patients, ExamRoom
  Records

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• The STATESETS Element
• The STATESETS element allows you to define
  different states for a resource. The format for
  the STATESETS element is summarized
  below.STATESETS Number, Name,
• State Name (Stateset type), ...
  repeatsExampleSTATESETS Oper1State,
  Lunch OvenState, Starved (Idle),
• Cook (Busy)

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• The FAILURES Element
• The FAILURES element provides the means to define
  the characteristics of failures that will be
  referenced by resources. This element can be used
  in conjunction with the STATESETS and RESOURCE
  elements to model resource failures.The FAILURES
  element is summarized below. FAILURES Number,
  Name, Type (Time Between Failures,
  Duration, State) RepeatsExampleFAILUR
  ES Electric, Time(3000,100) Jam,
  Time(EXPO(60),2,Busy) Maintenance,
  Count(300,120)

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• The RESOURCES Element
• The complete RESOURCES element is summarized
  below. RESOURCES Number, Name, Capacity
  Keyword (Capacity Expression, Capacity entity
  rule),
• StateSetID-Initial state,
• FAILURE(Fail ID, Failure entity rule), ...
  RepeatsExampleRESOURCES Operator,
  SCHEDULE(OpSched, Wait),, Failure(OpFail)
• Machine, 1, MachineStateSet

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• The FREQUENCIES Element
• The FREQUENCIES element provides the capability
  to obtain time-dependent statistics on the
  occurrence frequency of a SIMAN variable or
  expression. The FREQUENCIES element is summarized
  below. FREQUENCIES Number, Type (Expression),
  Name,
• Output File, Report ID, Value or Range,
  Category, Category Option ...
  repeatsExampleFREQUENCIES STATE(Oven),
  Oven States NQ(Buffer), Queue
  Statistics,,, 0 Range(0,1)
  Range(1,2) WIP, Work in Progress,,, Range(-50
  0,0), Backorder, Exclude Range(0,100), Normal
  Range(100,500), High

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• The ALTER, SELECT and PREEMPT Blocks
• The ALTER block, used to change the capacity of
  the resource, is summarized below.ALTER
  Resource ID, Capacity Change repeatsThe
  SELECT block can be used to model the process of
  selecting from among non-identical parallel
  resources. It is summarized below.SELECT, Resour
  ce Selection Rule Seize Label repeatsThe
  PREEMPT block can be used to take away a busy
  unit of the resource away from another entity
  that is currently using the resource. This
  happens only when all the units of the resource
  are busy and the arriving entity has a higher
  priority than the ones already using the
  resource.PREEMPT, Priority Resource ID,
  Attribute ID, Destination

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• Selecting Among Parallel QueuesThe PICKQ and
  QPICK Blocks
• The PICKQ block can be used to select from among
  multiple, parallel downstream queues for entity
  insertion. The PICKQ block is summarized
  below.PICKQ, Queue Selection Rule, Balk label
  Queue Label repeatsThe QPICK block can be
  used to select from among a parallel set of
  upstream queues. The QPICK block is summarized
  below.QPICK, Queue Selection Rule Queue
  Label repeats

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• Queue Manipulations
• The SEARCH and REMOVE Blocks
• The SEARCH block can be used to search a group
  or a queue from starting position BegJ to ending
  position EndJ for the rank J of the first entity
  that satisfies Condition. If Condition is not
  satisfied, set J equal to zero.SEARCH, Search
  item, BegJ, EndJ Search ConditionExample SE
  ARCH, JobQueue Parttype 1

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• The REMOVE block, shown below, can be used to
  remove an entity with a specified index or rank
  from queue QueueID and send it to a labeled
  block.REMOVE Rank, QueueID, Removed Entity
  DestinationExamplesREMOVE NQ, Buffer,
  JockeyREMOVE J, JobQueue, Renege

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• Evaluating System Status
• The FINDJ Block
• The FINDJ block, shown below, can be used to
  search from index BegJ to index EndJ to find the
  first J that satisfies the Condition. If
  Condition is not satisfied, set J equal to zero.
  Backward searching is permitted (BegJ gt
  EndJ).FINDJ, BegJ, EndJ, Search
  ConditionExampleFINDJ, 20, 15,
  MIN(NQ(J)/MR(J))

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• Conditional Hold
• The WAIT and SIGNAL Blocks
• The WAIT block holds the entities in the
  preceding queue until signal Code is received.
  When signal is received, release a maximum of
  WaitLimit entities.WAIT Signal code,
  WaitLimitExampleWAIT JobType, 2

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• The SIGNAL block send the signal code to each
  WAIT block. TotalLimit is the total number of
  entities released from all WAIT
  blocks.SIGNAL Signal code, TotalLimitExample
  SIGNAL Jobtype, 4

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• Experimental Rules
• The RULES Element
• Each number rule is used at an ALLOCATE, QPICK,
  PICKQ, REQUEST or SELECT block in the
  model.RULES Number, Rule repeatsExample
  RULES 1, SNQ 2-3, SRC

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• System Arrivals
• The ARRIVALS Element
• The ARRIVALS element can be used to assign
  values to consecutive attributes for the Numbered
  arrival with specified arrival Type, offset Time
  and Batchsize. Permissible Types are STATION
  (Station ID), QUEUE (QueueID) or BLOCK
  (BlockID).ARRIVALS Number, Type, Time,
  Batchsize, Assignments repeatsExampleARRI
  VALS 1, STATION (MachA), 10, 2, M4, NS 7 2,
  QUEUE(MachBQ),,,processTime3.5 3,
  BLOCK(15),12,,Weight 0.5

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• Queue Rankings
• The RANKINGS Element
• The RANKINGS element ranks the entities in
  QueueID according to queue ranking rule Ranking.
  RANKINGS QueueID, RankingrepeatsExampleR
  ANKINGS Mach1Q-Mach3Q, LVF(Process
  Time) Mach4Q, LIFO InspectQ, HVF(JobType)

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• Tabular Data
• The TABLES Element
• The TABLES element provides tabular data
  (Y-values) that can be accessed by the function
  TF(Table ID, Xvalue). TABLES Number, Name,
  Xlow, XInc, Y1,......,Yn repeatsTable with
  specified Number or Name has low value Xlow for
  the independent varaible X, and fixed increment
  Xinc between successive values for the dependent
  variable. The returned value is linearly
  interpolated if the Xvalue does not directly
  correspond to the defined increments.ExampleTA
  BLES Failure Rates, 10, 2, 0.6, 0.3, 0.25, 0.55,
  0.8 TF(FailureRates,14) 0.25 TF(FailureRate
  s,11) 0.45

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• Decision Logic
• The IF, ELSEIF, ELSE and ENDIF Blocks
• The IF, ELSEIF, ELSE, and ENDIF blocks can be
  used where different parts require different
  preparations before being processed - each
  requiring different actions.
• ExampleIF PartType 1 SEIZE
  Cleaner DELAY Cleantime
  RELEASE CleanerELSEIF PartType 2
  DELAY DryTimeELSE DELAY MoveTimeENDIF

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• Conditional Looping
• The WHILE and ENDWHILE Blocks
• The WHILE and ENDWHILE blocks, shown below, can
  be used to cause an entity to flow repeatedly
  through the same group of blocks for a specified
  number of times or until some condition has been
  met.ExampleAssign Count 0WHILE Count
  lt 5 .. .. Assign Count Count
  1ENDWHILE