Extending the smartcard personalisation system by the graphical treatment

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Extending the smart-card personalisation system
by the graphical treatment

• Angelika Mader
• University of Twente

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Cybernetix smart cardpersonalisation system
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Cybernetix- smart card personalisation system
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way of a single card through the system
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Cybernetix - smart card personalisation system
Research question can we use model checking
tools to find an optimal schedule? optimal means
optimal throughput because the belt is not
moving with constant speed, it is not the
number of gaps that we optimize. First approach
isolation of the personalisation part
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Isolation of the personalisation part
processing times Personalisation 10-50
Unloader, Loader, Flip-Over 2 Printer 3 Laser
Engraver 4 Belt movement 1
dominates
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smart card personalisationsuper single mode
personalisation stations
unloader
loader
belt
etc.
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First results

• problem difficult for model checking does not
  scale up to great numbers of cards
• for a periodic schedule we need some sort of
  cycle detection

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More first results
By elementary combinatorial argumentation the
throughput of the super-single mode is
k even number of stationsp personalisation time
Cycle length
The super-single mode meets the theoretical upper
bound for throughput,if p gt 4k1 (i.e.
personalisation time is long enough w.r.t. number
of stations)
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Alternative Architecture

• Why
• allows for an easier schedule and easier
  analysis
• argumentation transfer to the more complicated
  super-single mode
• different composition properties good for
  comparison

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Even more first results
By elementary combinatorial argumentation the
throughput of the alternative architecture is
k number of stationsp personalisation time
Cycle length
The alternative schedule meets the theoretical
upper bound for throughput,if p gt 4k-2 (i.e.
personalisation time is long enough w.r.t. number
of stations)
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Personalisation graphical treatment
processing times Personalisation 10-50
Unloader, Loader, Flip-Over 2 Printer 3 Laser
Engraver 4 Belt movement 1

• cards are processed on the belt
• cards do not overtake each other
• graphical treatment only adds delays

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Personalisation graphical treatment

• cards leave the personalisation part with a
  certain delay pattern (rythm) that depends on
  the schedule (the belt does not move with
  constant speed!)
• the time pattern interferes with the delays by
  the graphical treatment extreme cases are that
  the graphical treatment delays synchronize
  completely with the time pattern of the
  personalisation part and have no negative effect
  at all, or contrary, that the delays are added
  completely to the production time
• personalisation schedules interfere differently
  with graphical part this holds even for
  different optimal schedules (will be shown by
  experiments)
• timing analysis of interference does not seem
  possible using elementary reasoning
• use UPPAAL for throughput analysis of the
  composition of personalisation part and
  graphical part

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Personalisation graphical treatment
Timing analysis - idea Add explicit scheduling
process in the UPPAAL model, that enforces
super-single mode or the alternative schedule for
the personalisation part.
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process Personalisation1 clock pers_time state
PERSONALISING, IDLE init IDLE trans IDLE -gt
PERSONALISING guard card_id00, // no
card in the personalisation station
Belt1gt0, // there is an unpersonalised card
on the belt moving0 // belt
must stand still sync s_p1?
assign pers_time0,
card_id0Belt1, // load card in the pers.
station Belt10, // position
on the belt gets empty PERSONALISING -gt IDLE
guard pers_timegtPersonalise,
Belt10, // belt cell under station is
empty moving0 // belt must
stand still sync s_p1? assign
Belt1-card_id0, // put pers. card on the
belt card_id00 //
personalisation station is empty now
for example
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process Scheduler state S1, S2, S3, S4, S5, S6,
S7, S8, S9, S10, S11, S12, S13, S14, S15, S16,
S17, S18, S19, S20, , S95 init S1 trans S1
-gt S2sync s_ul! , // synchonizes with
unloader S2 -gt S3sync s_m!, // synchronizes
with belt S3 -gt S4sync s_m!, S4 -gt S5sync
s_ul! , S5 -gt S6sync s_m!, S6 -gt S7sync
s_m!, S21 -gt S22sync s_m!, S22 -gt S23sync
s_ul! , S23 -gt S24sync s_m!, S24 -gt S25sync
s_p1!, // synchronizes with personalisation
station 1 S25 -gt S26sync s_p2!, //
synchronizes with personalisation station 2 S26
-gt S27sync s_p3!, S27 -gt S28sync
s_p4!, ...
sequence of actions - not timing!
no synchronisation with graphical part!
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Personalisation graphical treatment

• Timing analysis experiments
• super-single mode and alternative schedule
• 4 and 8 personalisation stations
• pickdrop times (1/2 time unit or zero) at
  personalisation stations
• time measurements for 12,16,20,24 and
  16,24,32,40 cards until cycle length is
  determined.
• personalisation times 10,20,30,40,50
• cost-optimal UPPAAL

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Timing analysis -experiments
4 stations graphical treatment, super-single
mode alternative architecture
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Timing analysis -experiments
4 stations graphical treatment, super-single
mode alternative architecture
cycle lengths
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First new results

• decomposition helps to analyse more complex
  scheduling problems
• results from the analysis of the first part go
  into a explicit scheduler of the larger system
  (model)
• cycles could be detected (because we know batch
  size cards per cycle)
• with cycle length we also have throughput

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Second version of graphical treatment

• cards are printed on one side only
• Flip-overs (and laser engraver) are not in use
• each card can be printed at first OR second
  printer
• scheduling problem what is the best schedule
  for the printers when the personalisation part
  is in super-single mode or the alternative
  schedule?
• can be solved with cost-optimal UPPAAL
  by similar approach as for the first version

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Conclusions so far

• Personalisation part is dominant but not the
  only source of delay in the system
• Different optimal schedules can interfere
  differently with graphical treatment part
  optimality is not compositional
• Even if the whole problem is not (yet) solvable
  with model checking, model checking can be used
  for parts of solutions
• Decomposition method for complex schedules can
  help to find good schedules
• Mixed strategies can help

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What has to be done

• Schedule and timing analysis for faulty cards
  performance models?
• More experiments with different architectures
  (e.g. numbers of cells on the belt)