Towards an Automated Design of Application-specific Reconfigurable Logic

Reconfigurable logic is known to have the potential to provide better solutions than direct ASIC implementations or processors in some situations. A necessary prerequisite for area advantages compared to ASICs or a better energy efficiency than processors is an application specific design of the reconfigurable unit. Adapting it to the specific requirements of an application helps to compensate for the area and speed penalty introduced by reconfigurability. The data paths of reconfigurable units are best suited for data flow oriented tasks, but for many applications, both control flow and data flow must be handled, so a integration of the reconfigurable unit into a processor environment is an appropriate choice. By analysing the existing design flow and integration possibilities for reconfigurable units, a basis for discussing possible automation schemes and a standardised interface is defined. Possible future research could investigate an automated design support for the building blocks of reconfigurable units and the definition of a standard processor interface for some classes of reconfigurable units

Dynamics of Money and Income Distributions

We study the model of interacting agents proposed by Chatterjee et al that allows agents to both save and exchange wealth. Closed equations for the wealth distribution are developed using a mean field approximation. We show that when all agents have the same fixed savings propensity, subject to certain well defined approximations defined in the text, these equations yield the conjecture proposed by Chatterjee for the form of the stationary agent wealth distribution. If the savings propensity for the equations is chosen according to some random distribution we show further that the wealth distribution for large values of wealth displays a Pareto like power law tail, ie P(w)\sim w^{1+a}. However the value of $a$ for the model is exactly 1. Exact numerical simulations for the model illustrate how, as the savings distribution function narrows to zero, the wealth distribution changes from a Pareto form to to an exponential function. Intermediate regions of wealth may be approximately described by a power law with $a>1$. However the value never reaches values of \~ 1.6-1.7 that characterise empirical wealth data. This conclusion is not changed if three body agent exchange processes are allowed. We conclude that other mechanisms are required if the model is to agree with empirical wealth data.Comment: Sixteen pages, Seven figures, Elsevier style file. Submitted to Physica

Evaluation of two species, Cobia and Giant Grouper, as alternative species to farm in the WSSV affected areas of South East Queensland

In 2016/17, the Rocky Point Prawn Farm, along with other farms in the Logan River region of south-east Queensland, was severely affected by a white spot disease outbreak caused by the exotic white spot syndrome virus (WSSV). Measures enforced to eradicate WSSV resulted in a complete loss of stock and a ban on prawn production within the Logan River and wider Moreton Bay area until May 2018. As a result, Rocky Point Prawn Farms (RPPF) elected to investigate the feasibility of finfish aquaculture as an alternative to prawn farming. The current project was undertaken to assess the potential of two finfish species, Cobia (Rachycentron canadum) and Giant Grouper (Epinephelus lanceolatus) as alternative aquaculture candidates for the Rocky Point Prawn Farm and potentially other aquaculture enterprises. The study was developed and led by RPPF with assistance from The Company One (TCO) and the Department of Agriculture and Fisheries (DAF), with staff from the Bribie Island Research Centre (BIRC) and ran from March 2017 until June 2018. In the study, the commercial performance of each species was assessed when cultured in both indoor tank systems and outdoors in cages. Culture facilities at two of RPPF’s production sites included a former prawn hatchery building which housed the indoor tank-based production, and an outdoor landlocked saline lake which contained cages. Cobia fingerlings were produced at BIRC and Giant Grouper fingerlings were supplied by TCO hatchery in Cairns. All fingerlings were initially grown in indoor tanks under controlled temperature conditions and later some were transferred to outdoor cages to assess their performance in both winter and spring/summer. Fish were fed once or twice per day and water quality data was collected daily. Weight and health checks were conducted monthly and any mortalities were removed from tanks or cages daily. The data were used to calculate key production parameters of feed conversion ratio, growth rate and survival throughout the production cycle. Both species were grown to harvest and sold into the domestic market. The production and market information generated by this project provided a framework to evaluate the relative costs and benefits of the two species within the range of production methods and strategies available to RPPF, and guidance towards future investment and optimising production in the future

Efficient Error-Tolerant Quantized Neural Network Accelerators

Neural Networks are currently one of the most widely deployed machine learning algorithms. In particular, Convolutional Neural Networks (CNNs), are gaining popularity and are evaluated for deployment in safety critical applications such as self driving vehicles. Modern CNNs feature enormous memory bandwidth and high computational needs, challenging existing hardware platforms to meet throughput, latency and power requirements. Functional safety and error tolerance need to be considered as additional requirement in safety critical systems. In general, fault tolerant operation can be achieved by adding redundancy to the system, which is further exacerbating the computational demands. Furthermore, the question arises whether pruning and quantization methods for performance scaling turn out to be counterproductive with regards to fail safety requirements. In this work we present a methodology to evaluate the impact of permanent faults affecting Quantized Neural Networks (QNNs) and how to effectively decrease their effects in hardware accelerators. We use FPGA-based hardware accelerated error injection, in order to enable the fast evaluation. A detailed analysis is presented showing that QNNs containing convolutional layers are by far not as robust to faults as commonly believed and can lead to accuracy drops of up to 10%. To circumvent that, we propose two different methods to increase their robustness: 1) selective channel replication which adds significantly less redundancy than used by the common triple modular redundancy and 2) a fault-aware scheduling of processing elements for folded implementationsComment: 6 pages, 5 figure

Karatsuba with Rectangular Multipliers for FPGAs

Best paper awardInternational audienceThis work presents an extension of Karatsuba's method to efficiently use rectangular multipliers as a base for larger multipliers. The rectangular multipliers that motivate this work are the embedded 18×25-bit signed multipliers found in the DSP blocks of recent Xilinx FPGAs: The traditional Karatsuba approach must under-use them as square 18×18 ones. This work shows that rectangular multipliers can be efficiently exploited in a modified Karatsuba method if their input word sizes have a large greatest common divider. In the Xilinx FPGA case, this can be obtained by using the embedded multipliers as 16×24 unsigned and as 17×25 signed ones. The obtained architectures are implemented with due detail to architectural features such as the pre-adders and post-adders available in Xilinx DSP blocks. They are synthesized and compared with traditional Karatsuba, but also with (non-Karatsuba) state-of-the-art tiling techniques that make use of the full rectangular multipliers. The proposed technique improves resource consumption and performance for multipliers of numbers larger than 64 bits

The simulation of action disorganisation in complex activities of daily living

Action selection in everyday goal-directed tasks of moderate complexity is known to be subject to breakdown following extensive frontal brain injury. A model of action selection in such tasks is presented and used to explore three hypotheses concerning the origins of action disorganisation: that it is a consequence of reduced top-down excitation within a hierarchical action schema network coupled with increased bottom-up triggering of schemas from environmental sources, that it is a more general disturbance of schema activation modelled by excessive noise in the schema network, and that it results from a general disturbance of the triggering of schemas by object representations. Results suggest that the action disorganisation syndrome is best accounted for by a general disturbance to schema activation, while altering the balance between top-down and bottom-up activation provides an account of a related disorder - utilisation behaviour. It is further suggested that ideational apraxia (which may result from lesions to left temporoparietal areas and which has similar behavioural consequences to action disorganisation syndrome on tasks of moderate complexity) is a consequence of a generalised disturbance of the triggering of schemas by object representations. Several predictions regarding differences between action disorganisation syndrome and ideational apraxia that follow from this interpretation are detailed