Toolflows for Mapping Convolutional Neural Networks on FPGAs: A Survey and Future Directions

In the past decade, Convolutional Neural Networks (CNNs) have demonstrated state-of-the-art performance in various Artificial Intelligence tasks. To accelerate the experimentation and development of CNNs, several software frameworks have been released, primarily targeting power-hungry CPUs and GPUs. In this context, reconfigurable hardware in the form of FPGAs constitutes a potential alternative platform that can be integrated in the existing deep learning ecosystem to provide a tunable balance between performance, power consumption and programmability. In this paper, a survey of the existing CNN-to-FPGA toolflows is presented, comprising a comparative study of their key characteristics which include the supported applications, architectural choices, design space exploration methods and achieved performance. Moreover, major challenges and objectives introduced by the latest trends in CNN algorithmic research are identified and presented. Finally, a uniform evaluation methodology is proposed, aiming at the comprehensive, complete and in-depth evaluation of CNN-to-FPGA toolflows.Comment: Accepted for publication at the ACM Computing Surveys (CSUR) journal, 201

Approximate FPGA-based LSTMs under Computation Time Constraints

Recurrent Neural Networks and in particular Long Short-Term Memory (LSTM) networks have demonstrated state-of-the-art accuracy in several emerging Artificial Intelligence tasks. However, the models are becoming increasingly demanding in terms of computational and memory load. Emerging latency-sensitive applications including mobile robots and autonomous vehicles often operate under stringent computation time constraints. In this paper, we address the challenge of deploying computationally demanding LSTMs at a constrained time budget by introducing an approximate computing scheme that combines iterative low-rank compression and pruning, along with a novel FPGA-based LSTM architecture. Combined in an end-to-end framework, the approximation method's parameters are optimised and the architecture is configured to address the problem of high-performance LSTM execution in time-constrained applications. Quantitative evaluation on a real-life image captioning application indicates that the proposed methods required up to 6.5x less time to achieve the same application-level accuracy compared to a baseline method, while achieving an average of 25x higher accuracy under the same computation time constraints.Comment: Accepted at the 14th International Symposium in Applied Reconfigurable Computing (ARC) 201

Matter density perturbations in modified gravity models with arbitrary coupling between matter and geometry

We consider theories with an arbitrary coupling between matter and gravity and obtain the perturbation equation of matter on subhorizon scales. Also, we derive the effective gravitational constant $G_{eff}$ and two parameters $\Sigma$ and $\eta$, which along with the perturbation equation of the matter density are useful to constrain the theory from growth factor and weak lensing observations. Finally, we use a completely solvable toy model which exhibits nontrivial phenomenology to investigate specific features of the theory. We obtain the analytic solution of the modified Friedmann equation for the scale factor $a$ in terms of time $t$ and use the age of the oldest star clusters and the primordial nucleosynthesis bounds in order to constrain the parameters of our toy model.Comment: 9 pages, 3 figures, uses revtex4, added Appendix and references, minor changes, accepted in Phys. Rev. D (to appear

High-level secretion of native recombinant human calreticulin in yeast

Additional file 2. Elution profiles of recombinant CRT in anion-exchange chromatography. Separation of CRT from S. cerevisiae (A and B) was performed on a pre-packed 5 ml Q-Sepharose column (GE LifeSciences cat. no. 17-5156-01), equilibrated with 20 mM l-His, pH 5.5, 100 mM NaCl buffer, in 15 column volumes linear gradient from 100 mM to 500 mM NaCl. Separation of CRT from P. pastoris (C and D) was performed on a 15 ml Q-Sepharose sorbent (GE LifeSciences cat. no. 17-0510-10) packed into the XK 16/20 column (GE Lifesciences, cat. no. 28-9889-37), equilibrated with 20 mM l-His, pH 5.5, 100 mM NaCl buffer, in 10 column volumes linear gradient from 100 to 500 mM NaCl. Elution profiles (A and C) and SDS-PAGE gels of corresponding fractions (B and D) are shown. Dashed lines define fractions that were pooled and used for further experiments with purified protein

Iso-osmotic regulation of nitrate accumulation in lettuce (Lactuca sativa L.)

Concerns about possible health hazards arising from human consumption of lettuce and other edible vegetable crops with high concentrations of nitrate have generated demands for a greater understanding of processes involved in its uptake and accumulation in order to devise more sustainable strategies for its control. This paper evaluates a proposed iso-osmotic mechanism for the regulation of nitrate accumulation in lettuce (Lactuca sativa L.) heads. This mechanism assumes that changes in the concentrations of nitrate and all other endogenous osmotica (including anions, cations and neutral solutes) are continually adjusted in tandem to minimise differences in osmotic potential of the shoot sap during growth, with these changes occurring independently of any variations in external water potential. The hypothesis was tested using data from six new experiments, each with a single unique treatment comprising a separate combination of light intensity, N source (nitrate with or without ammonium) and nitrate concentration carried out hydroponically in a glasshouse using a butterhead lettuce variety. Repeat measurements of plant weights and estimates of all of the main soluble constituents (nitrate, potassium, calcium, magnesium, organic anions, chloride, phosphate, sulphate and soluble carbohydrates) in the shoot sap were made at intervals from about 2 weeks after transplanting until commercial maturity, and the data used to calculate changes in average osmotic potential in the shoot. Results showed that nitrate concentrations in the sap increased when average light levels were reduced by between 30 and 49 % and (to a lesser extent) when nitrate was supplied at a supra-optimal concentration, and declined with partial replacement of nitrate by ammonium in the external nutrient supply. The associated changes in the proportions of other endogenous osmotica, in combination with the adjustment of shoot water content, maintained the total solute concentrations in shoot sap approximately constant and minimised differences in osmotic potential between treatments at each sampling date. There was, however, a gradual increase in osmotic potential (ie a decline in total solute concentration) over time largely caused by increases in shoot water content associated with the physiological and morphological development of the plants. Regression analysis using normalised data (to correct for these time trends) showed that the results were consistent with a 1:1 exchange between the concentrations of nitrate and the sum of all other endogenous osmotica throughout growth, providing evidence that an iso-osmotic mechanism (incorporating both concentration and volume regulation) was involved in controlling nitrate concentrations in the shoot

Seizure activity after xylazine administration in a horse

Δύστροπος επιβήτορας, που προσκομίστηκε για ορχεκτομή, εμφάνισε έντονο στρες κατά την προσπάθεια συγκράτησης του για την τοποθέτηση σφαγιτιδικου καθετήρα. Η χορήγηση ξυλαζίνης ενδοφλέβια κατευθείαν από τη σύριγγα προκάλεσε την κατάρρευση του ζώου και την ανάπτυξη επιληπτικής κρίσης. Η κατάσταση αντιμετωπίστηκε επιτυχώς με τη χορήγηση ακετυλοπρομαζίνης και υγρών ενδοφλεβίως. Η επιληπτική κρίση λύθηκε μέσα σε δυο περίπου λεπτά. Περίπου 90 λεπτά μετά τηνπτώση του το ζώο στάθηκε όρθιο. Δεν διαπιστώθηκε ένδειξη σχηματισμού αιματώματος στην περιοχή της έγχυσης της ξυλαζίνης. Η επέμβαση έγινε 8 ημέρες μετά το επεισόδιο, χωρίς επιπλοκές. Η ξυλαζίνη σε καταστάσεις στρες μπορεί να διεγείρει περισσότεροτους α1- και λιγότερο τους α2-αδρενεργικους υποδοχείς, με αποτέλεσματη διέγερση του κεντρικού νευρικού συστήματος. Επίσης,υπάρχει η πιθανότητα η ξυλαζίνη να ευαισθητοποίησε το μυοκάρδιο στις ενδογενείς κατεχολαμίνες, με αποτέλεσμα τις καρδιακές αρρυθμίες και την εγκεφαλική υποξία. Η χρήση της ξυλαζίνης σε στρεσαρισμένα ζώα μπορεί να αυξήσει τις πιθανότητες εμφάνισης ανεπιθύμητων ενεργειών.A vicious stallion, schedule for castration, became very stressed during the attempts to place a jugular catheter. Finally, xylazine was injected direcdy from the syringe into the jugular vein and immediately the animal fell down and developed seizures. Acepromazine and fluids were administered to successfully treat the condition. No evidence of haematoma formation was noticed. Xylazine in stressed animals may activate al-adrenoceptors, resulting to central neural system excitement and seizures. Moreover, xylazine may had sensitized the myocardium to endogenous catecholamines, resulting to cardiac arrhythmias, cerebral hypoxia and seizures. Xylazine administration in stressed animals may increase the incidence of adverse reactions