4 research outputs found
Neural networks-on-chip for hybrid bio-electronic systems
PhD ThesisBy modelling the brains computation we can further our understanding
of its function and develop novel treatments for neurological disorders. The
brain is incredibly powerful and energy e cient, but its computation does
not t well with the traditional computer architecture developed over the
previous 70 years. Therefore, there is growing research focus in developing
alternative computing technologies to enhance our neural modelling capability,
with the expectation that the technology in itself will also bene t from
increased awareness of neural computational paradigms.
This thesis focuses upon developing a methodology to study the design
of neural computing systems, with an emphasis on studying systems suitable
for biomedical experiments. The methodology allows for the design to be
optimized according to the application. For example, di erent case studies
highlight how to reduce energy consumption, reduce silicon area, or to
increase network throughput.
High performance processing cores are presented for both Hodgkin-Huxley
and Izhikevich neurons incorporating novel design features. Further, a complete
energy/area model for a neural-network-on-chip is derived, which is
used in two exemplar case-studies: a cortical neural circuit to benchmark
typical system performance, illustrating how a 65,000 neuron network could
be processed in real-time within a 100mW power budget; and a scalable highperformance
processing platform for a cerebellar neural prosthesis. From
these case-studies, the contribution of network granularity towards optimal
neural-network-on-chip performance is explored
Scheduling and reconfiguration of interconnection network switches
Interconnection networks are important parts of modern computing systems, facilitating communication between a system\u27s components. Switches connecting various nodes of an interconnection network serve to move data in the network. The switch\u27s delay and throughput impact the overall performance of the network and thus the system. Scheduling efficient movement of data through a switch and configuring the switch to realize a schedule are the main themes of this research. We consider various interconnection network switches including (i) crossbar-based switches, (ii) circuit-switched tree switches, and (iii) fat-tree switches. For crossbar-based input-queued switches, a recent result established that logarithmic packet delay is possible. However, this result assumes that packet transmission time through the switch is no less than schedule-generation time. We prove that without this assumption (as is the case in practice) packet delay becomes linear. We also report results of simulations that bear out our result for practical switch sizes and indicate that a fast scheduling algorithm reduces not only packet delay but also buffer size. We also propose a fast mesh-of-trees based distributed switch scheduling (maximal-matching based) algorithm that has polylog complexity. A circuit-switched tree (CST) can serve as an interconnect structure for various computing architectures and models such as the self-reconfigurable gate array and the reconfigurable mesh. A CST is a tree structure with source and destination processing elements as leaves and switches as internal nodes. We design several scheduling and configuration algorithms that distributedly partition a given set of communications into non-conflicting subsets and then establish switch settings and paths on the CST corresponding to the communications. A fat-tree is another widely used interconnection structure in many of today\u27s high-performance clusters. We embed a reconfigurable mesh inside a fat-tree switch to generate efficient connections. We present an R-Mesh-based algorithm for a fat-tree switch that creates buses connecting input and output ports corresponding to various communications using that switch