Biomedical Engineering Reference
In-Depth Information
Re-execution
subroutine
Checkpoint
C
2
Pass
O
1
O
2
O
3
Checkpoint
C
1
Fail
O
4
Figure 7.3
Backtrace algorithm and reexecution subroutine.
to tell which path causes the error. However, since all the operations in these
paths are scheduled between C
1
and C
2
, in practice, we can correct the error
by reexecuting all these operations.
7.2.2.2 Control-Path Synthesis
Next, we discuss the implementation of the control path, a step referred to as
control-path synthesis. We focus here on the synthesis of checkpoints. The
goal is to incorporate checkpoints into the synthesis result for a bioassay
without a control path.
Each checkpoint can be mapped to a detection operation and inserted
into the sequencing graph at the same location. For instance, a checkpoint
located between operations
O
2
and
O
3
in Figure 7.4 is mapped to a detec-
tion operation at the same position. By applying the synthesis method of
Chapter 2 to this modified sequencing graph, the control path can be easily
incorporated as part of the bioassay protocol. Checkpoints are then mapped
to on-chip sensors. The corresponding intermediate product droplets will
be routed to the sensors for detection at a scheduled time point. The sensor
output is sent to the microcontroller that coordinates bioassay execution. The
bioassay synthesis results are mapped to a software program and stored in
O
2
O
1
O
2
O
1
Checkpoint
Det.
Incorporating
a checkpoint into
a sequencing graph
O
3
O
3
Figure 7.4
The incorporation of a checkpoint to a sequencing graph (
Det.
refers to detection operation).