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							193 lines
						
					
					
						
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							193 lines
						
					
					
						
							11 KiB
						
					
					
				
								// CROWDS [Reiter,Rubin]
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								// Vitaly Shmatikov, 2002
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								// Modified by Ernst Moritz Hahn (emh@cs.uni-sb.de)
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								// note:
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								// Change everything marked CWDSIZ when changing the size of the crowd
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								// Change everything marked CWDMAX when increasing max size of the crowd
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								dtmc
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								// Model parameters
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								const double PF;  // forwarding probability
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								const double badC = 0.167;  // probability that member is untrustworthy
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								// Probability of forwarding
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								// const double    PF = 0.8;
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								// const double notPF = 0.2;  // must be 1-PF
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								// Probability that a crowd member is bad
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								// const double  badC = 0.1;
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								// const double  badC = 0.091;
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								// const double  badC = 0.167;
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								// const double goodC = 0.909;  // must be 1-badC
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								// const double goodC = 0.833;  // must be 1-badC
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								const int CrowdSize = 10; // CWDSIZ: actual number of good crowd members
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								const int TotalRuns = 5; // Total number of protocol runs to analyze
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								const int MaxGood=20; // CWDMAX: maximum number of good crowd members
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								// Process definitions
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								module crowds
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									// Auxiliary variables
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									launch:   bool init true;       // Start modeling?
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									newInstance:      bool init false;      // Initialize a new protocol instance?
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									runCount: [0..TotalRuns] init TotalRuns;   // Counts protocol instances
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									start:    bool init false;      // Start the protocol?
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									run:      bool init false;      // Run the protocol?
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									lastSeen: [0..MaxGood] init 0;   // Last crowd member to touch msg
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									good:     bool init false;      // Crowd member is good?
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									bad:      bool init false;      //              ... bad?
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									recordLast: bool init false;    // Record last seen crowd member?
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									badObserve: bool init false;    // Bad members observes who sent msg?
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									deliver:  bool init false;      // Deliver message to destination?
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									done:     bool init false;      // Protocol instance finished?
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									// Counters for attackers' observations
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									// CWDMAX: 1 counter per each good crowd member
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									observe0:  [0..TotalRuns];
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									observe1:  [0..TotalRuns];
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									observe2:  [0..TotalRuns];
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									observe3:  [0..TotalRuns];
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									observe4:  [0..TotalRuns];
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									observe5:  [0..TotalRuns];
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									observe6:  [0..TotalRuns];
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									observe7:  [0..TotalRuns];
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									observe8:  [0..TotalRuns];
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									observe9:  [0..TotalRuns];
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									observe10: [0..TotalRuns];
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									observe11: [0..TotalRuns];
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									observe12: [0..TotalRuns];
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									observe13: [0..TotalRuns];
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									observe14: [0..TotalRuns];
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									observe15: [0..TotalRuns];
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									observe16: [0..TotalRuns];
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									observe17: [0..TotalRuns];
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									observe18: [0..TotalRuns];
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									observe19: [0..TotalRuns];
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									[] launch -> (newInstance'=true) & (runCount'=TotalRuns) & (launch'=false);
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									// Set up a newInstance protocol instance
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									[] newInstance & runCount>0 -> (runCount'=runCount-1) & (newInstance'=false) & (start'=true);
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									// SENDER
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									// Start the protocol
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									[] start -> (lastSeen'=0) & (run'=true) & (deliver'=false) & (start'=false);
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									// CROWD MEMBERS
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									// Good or bad crowd member?
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									[] !good & !bad & !deliver & run ->
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									              1-badC : (good'=true) & (recordLast'=true) & (run'=false) +
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									               badC : (bad'=true)  & (badObserve'=true) & (run'=false);
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									// GOOD MEMBERS
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									// Forward with probability PF, else deliver
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									[] good & !deliver & run -> PF : (good'=false) + 1-PF : (deliver'=true);
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									// Record the last crowd member who touched the msg;
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									// all good members may appear with equal probability
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									//    Note: This is backward.  In the real protocol, each honest
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									//          forwarder randomly chooses the next forwarder.
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									//          Here, the identity of an honest forwarder is randomly
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									//          chosen *after* it has forwarded the message.
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									[] recordLast & CrowdSize=2 ->
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									        1/2 : (lastSeen'=0) & (recordLast'=false) & (run'=true) +
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									        1/2 : (lastSeen'=1) & (recordLast'=false) & (run'=true);
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									[] recordLast & CrowdSize=3 ->
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									        1/3 : (lastSeen'=0) & (recordLast'=false) & (run'=true) +
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									        1/3 : (lastSeen'=1) & (recordLast'=false) & (run'=true) +
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									        1/3 : (lastSeen'=2) & (recordLast'=false) & (run'=true);
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									[] recordLast & CrowdSize=4 ->
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									        1/4 : (lastSeen'=0) & (recordLast'=false) & (run'=true) +
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									        1/4 : (lastSeen'=1) & (recordLast'=false) & (run'=true) +
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									        1/4 : (lastSeen'=2) & (recordLast'=false) & (run'=true) +
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									        1/4 : (lastSeen'=3) & (recordLast'=false) & (run'=true);
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									[] recordLast & CrowdSize=5 ->
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									        1/5 : (lastSeen'=0) & (recordLast'=false) & (run'=true) +
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									        1/5 : (lastSeen'=1) & (recordLast'=false) & (run'=true) +
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									        1/5 : (lastSeen'=2) & (recordLast'=false) & (run'=true) +
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									        1/5 : (lastSeen'=3) & (recordLast'=false) & (run'=true) +
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									        1/5 : (lastSeen'=4) & (recordLast'=false) & (run'=true);
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									[] recordLast & CrowdSize=10 ->
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									        1/10 : (lastSeen'=0) & (recordLast'=false) & (run'=true) +
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									        1/10 : (lastSeen'=1) & (recordLast'=false) & (run'=true) +
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									        1/10 : (lastSeen'=2) & (recordLast'=false) & (run'=true) +
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									        1/10 : (lastSeen'=3) & (recordLast'=false) & (run'=true) +
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									        1/10 : (lastSeen'=4) & (recordLast'=false) & (run'=true) +
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									        1/10 : (lastSeen'=5) & (recordLast'=false) & (run'=true) +
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									        1/10 : (lastSeen'=6) & (recordLast'=false) & (run'=true) +
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									        1/10 : (lastSeen'=7) & (recordLast'=false) & (run'=true) +
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									        1/10 : (lastSeen'=8) & (recordLast'=false) & (run'=true) +
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									        1/10 : (lastSeen'=9) & (recordLast'=false) & (run'=true);
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									[] recordLast & CrowdSize=15 ->
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									        1/15 : (lastSeen'=0)  & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=1)  & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=2)  & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=3)  & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=4)  & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=5)  & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=6)  & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=7)  & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=8)  & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=9)  & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=10) & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=11) & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=12) & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=13) & (recordLast'=false) & (run'=true) +
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									        1/15 : (lastSeen'=14) & (recordLast'=false) & (run'=true);
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									[] recordLast & CrowdSize=20 ->
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									        1/20 : (lastSeen'=0)  & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=1)  & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=2)  & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=3)  & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=4)  & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=5)  & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=6)  & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=7)  & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=8)  & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=9)  & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=10) & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=11) & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=12) & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=13) & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=14) & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=15) & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=16) & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=17) & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=18) & (recordLast'=false) & (run'=true) +
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									        1/20 : (lastSeen'=19) & (recordLast'=false) & (run'=true);
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									// BAD MEMBERS
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									// Remember from whom the message was received and deliver
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									// CWDMAX: 1 rule per each good crowd member
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									[] lastSeen=0  & badObserve & observe0 <TotalRuns -> (observe0' =observe0 +1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=1  & badObserve & observe1 <TotalRuns -> (observe1' =observe1 +1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=2  & badObserve & observe2 <TotalRuns -> (observe2' =observe2 +1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=3  & badObserve & observe3 <TotalRuns -> (observe3' =observe3 +1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=4  & badObserve & observe4 <TotalRuns -> (observe4' =observe4 +1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=5  & badObserve & observe5 <TotalRuns -> (observe5' =observe5 +1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=6  & badObserve & observe6 <TotalRuns -> (observe6' =observe6 +1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=7  & badObserve & observe7 <TotalRuns -> (observe7' =observe7 +1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=8  & badObserve & observe8 <TotalRuns -> (observe8' =observe8 +1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=9  & badObserve & observe9 <TotalRuns -> (observe9' =observe9 +1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=10 & badObserve & observe10<TotalRuns -> (observe10'=observe10+1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=11 & badObserve & observe11<TotalRuns -> (observe11'=observe11+1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=12 & badObserve & observe12<TotalRuns -> (observe12'=observe12+1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=13 & badObserve & observe13<TotalRuns -> (observe13'=observe13+1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=14 & badObserve & observe14<TotalRuns -> (observe14'=observe14+1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=15 & badObserve & observe15<TotalRuns -> (observe15'=observe15+1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=16 & badObserve & observe16<TotalRuns -> (observe16'=observe16+1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=17 & badObserve & observe17<TotalRuns -> (observe17'=observe17+1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=18 & badObserve & observe18<TotalRuns -> (observe18'=observe18+1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									[] lastSeen=19 & badObserve & observe19<TotalRuns -> (observe19'=observe19+1) & (deliver'=true) & (run'=true) & (badObserve'=false);
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									// RECIPIENT
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									// Delivery to destination
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									[] deliver & run -> (done'=true) & (deliver'=false) & (run'=false) & (good'=false) & (bad'=false);
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									// Start a newInstance instance
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									[] done -> (newInstance'=true) & (done'=false) & (run'=false) & (lastSeen'=MaxGood);
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								endmodule
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								label "observe0Greater1" = observe0 > 1;
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