Hardware Reference
In-Depth Information
4.3
Operation-Dependency-Aware Synthesis
In this section, we describe how synthesis results can be achieved in the presence of
completion-time uncertainties of fluidic operations. Using the proposed algorithm,
we can obtain the synthesis results that include: (i) the result of module-placement
for each operation; (ii) the set of operations to be implemented in each D/M
phase. It is important to note that, the exact start time and end time of operations
are not included in the results derived by the proposed synthesis algorithm; they
are determined based on the feedback from sensors during the bioassay run-time.
Therefore, the derived synthesis results are semi-deterministic.
The proposed synthesis algorithm focuses on the interdependency among dilu-
tion/mixing operations that are given by the sequencing graph of a bioassay.
A sequencing graph is an abstract description for a bioassay; each node in the graph
represents a fluidic operation, and each edge represents the interdependency for a
pair of operations. For any two operations O
a
and O
b
, if the output droplet of O
a
is
the input of O
b
, then there is an edge from O
a
to O
b
. The sequencing graph in this
approach is reduced by deleting all nodes that represent dispensing operations. Two
examples of sequences graphs for bioassays are shown in Fig.
4.3
a, b, respectively.
A sequencing graph for a bioassay has two important properties: (i) it is a
directed acyclic graph, because there is no infinite loop or repeated step in identical
a
b
2
3
4
1
6
7
c
S
R
S
L
8
9
1
6
N
R
5
2
t
d
e
g
Region assigned
for
operation 6
Storage unit
S
2
f
S
1
Mixing region
M
S
L
M
S
R
1
2
1
2
3
4
12
N
R
5
Fig. 4.3
Sequencing graph with tree structure (
a
) all edges are directed towards the root of the tree;
and (
b
) all edges are directed away from the root; (
c
) scheduling results for mixing operations
1
,
2
,
and
6
;(
d
) module-placement for
1
,
2
and
6
;(
e
) storage units S
1
and S
2
inside the modules assigned
for operations
1
and
2
;(
f
) packaged macro-operations M
S
L
and M
S
R
;(
g
) a feasible solution for
module-placements of operation
1
5
on an 8
8 array
