[Retracted] Dynamic Performance Analysis of STEP System in Internet of Vehicles Based on Queuing Theory

Table 1

The core algorithm of the STEP event stream processing system.

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Algorithm event stream processing algorithm based on Petri net model

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Input: event stream, petri net model of the query expressions

Output: query results

(1)  while TRUE do

(2)   Event ← the pointer point the current event;

(3)   foreach Event.Attribute do

(4)    TransitionStart.InputToken ← Event.Attribute;

(5)   end

(6)   foreach TransitionStart do

(7)    if TransitionStart.InputToken meet current guard then

(8)     OutputToken ← InputToken;

(9)    else

(10)     End the query and jump to statement 28;

(11)    end

(12)   end

(13)   foreach TransitionMid do

(14)    if TransitionMid.InputToken meet guard then

(15)     OutputToken ← OutputToken ⊙ InputToken;

(16)    else

(17)     End the query and jump to statement 28;

(18)    end

(19)   end

(20)   foreach TransitionEnd do

(21)    if TransitionEnd.InputToken meet guard then

(22)     OutputToken ← OutputToken ⊙ InputToken;

(23)     return TransitionEnd.OutputToken;

(24)    else

(25)     End the query and jump to statement 28;

(26)    end

(27)   end

(28)   Delete the current event, the pointer point the next event;

(29)  end

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