An Adiabatic Capacitive Artificial Neuron With RRAM-Based Threshold Detection for Energy-Efficient Neuromorphic Computing

In the quest for low power, bio-inspired computation both memristive and memcapacitive-based Artificial Neural Networks (ANN) have been the subjects of increasing focus for hardware implementation of neuromorphic computing. One step further, regenerative capacitive neural networks, which call for the use of adiabatic computing, offer a tantalising route towards even lower energy consumption, especially when combined with `memimpedace' elements. Here, we present an artificial neuron featuring adiabatic synapse capacitors to produce membrane potentials for the somas of neurons; the latter implemented via dynamic latched comparators augmented with Resistive Random-Access Memory (RRAM) devices. Our initial 4-bit adiabatic capacitive neuron proof-of-concept example shows 90% synaptic energy saving. At 4 synapses/soma we already witness an overall 35% energy reduction. Furthermore, the impact of process and temperature on the 4-bit adiabatic synapse shows a maximum energy variation of 30% at 100 degree Celsius across the corners without any functionality loss. Finally, the efficacy of our adiabatic approach to ANN is tested for 512 & 1024 synapse/neuron for worst and best case synapse loading conditions and variable equalising capacitance's quantifying the expected trade-off between equalisation capacitance and range of optimal power-clock frequencies vs. loading (i.e. the percentage of active synapses).Comment: This work has been accepted to the IEEE TCAS-

Machining Characteristics and Parametric Optimisation of Inconel 825 during Electric Discharge Machining

This paper presents the machining characteristics and parametric optimisation of Inconel 825 during die-sinking electrical discharge machining (EDM) process. This work considers seven input parameters out of which six are of three levels and one is of one level. Metal removal rate (MRR), tool wear rate (TWR) and surface roughness (SR) have been considered as performance measures. Before carrying out physical experimental runs, the experiments have been designed using Taguchi’s L36 (21 × 36) orthogonal array (OA). In order to identify the significant input parameters, Analysis of Variance has been employed on the experimental data. Discharge current, pulse-on-time, tool material and tool electrode lift time are found as significant input parameters. The effects of these significant parameters on the performance measures have been presented using Taguchi\u27s technique. After machining, study of surface characteristics of the electric discharged machined surface has been carried out using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDXS) and X-ray diffraction (XRD). These studies help in obtaining the information pertaining to topography of the machined surface, material transfer from tool and dielectric to the machined surface, and presence of extra element and their different phases at the machined surface. It has been found from the research that Carbon, Oxygen, Iron, Nickel, Chromium and little amount of Molybdenum are transferred to the surface of work piece. Further, for the best yield of the process, the optimal combination of input parameters has been obtained and reported using Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) as a multi-objective optimisation technique. Consideration of two different dielectric fluids and three different electrode materials is the novelty of the work

Association between red cell transfusions and necrotizing enterocolitis

OBJECTIVE: Several case reports and retrospective studies have reported a temporal association between red blood cell (RBC) transfusions and necrotizing enterocolitis (NEC). In this article, we review the clinical evidence and biological plausibility of the association between RBC transfusions and NEC. METHODS: A literature search was performed using the databases PubMed, EMBASE, and Scopus, and the electronic archive of abstracts presented at the annual meetings of the Pediatric Academic Societies. RESULTS: Among all cases of NEC, 25 -40% patients were noted to have received an RBC transfusion within a 48 hour period prior to onset of NEC. Compared to infants who developed NEC unrelated to transfusion, neonates with transfusion-associated NEC were born at an earlier gestation, had lower birth weights, and had a delayed onset at 3-5 weeks of postnatal age. CONCLUSIONS: Based on current clinical evidence, transfusion-associated NEC appears to be a plausible clinical entity. However, there is a need for cautious interpretation of data because all the studies that have been conducted until date are retrospective, and therefore, susceptible to bias. A large, prospective, multi-center trial is needed to evaluate the association between RBC transfusion and NEC

Towards devising pilot experiments to establish parameter window for FSP of aluminum alloys

One of the major challenges encountered during friction stir processing (FSP) is the establishment of a process parameter window in order to achieve processed surfaces with an acceptable quality as it is an exhaustive task that involves enormous resources, time and efforts. Sometimes this task is so difficult that the trial may run into futility. This work belongs to a theme of FSP that is not much reported in the literature. This is a maiden work to lay a roadmap for the FSP parameter range in a quick and effective manner. The present study results from first-hand experiments performed to produce surface composites on AA6063 alloy using a mixture of SiC+Fe+Mn+Sn as reinforcement in such a manner that a novice professional can pan out ways to identify and classify irregularities/defects, associate them with the causes and obtain feasible parameter window. In this work, a methodology for identification and selection of optimum tool speed (rpm), processing speed and plunge depth has been demonstrated. The parameter window was established by analysing main surface irregularities associated with the parameters and taking corrective modification to eventually arrive at the feasible range. The established range was validated through an experiment performed with the parameters lying within the established window. The validation was supported with microstructural characterization, micro-hardness measurement, thermal analysis, corrosion analysis and the comprehensive analysis presented in this work has been done with the help of the image processing technique. Results show that grain refinement and homogeneous distribution of reinforcement present in the stir zone developed during FSP at the appropriate process parameters. Furthermore, grain refinement enhances the hardness by 28.29% and the corrosion resistance by 13.6%. The highest temperature i.e. 423.25°C is achieved on the advancing side of the processed zone

Imaging of Knee Joint Pathologies: A Comparative Study of Ultrasound and Magnetic Resonance Imaging

Background: Magnetic resonance imaging (MRI) has been accepted as the best non-invasive imaging modality for the evaluation of knee joint pathology but the advantages of ultrasound (US) over magnetic resonance imaging (MRI) are that the ultrasound is readily available, cheap and offers real-time imaging. Aim: To assess the accuracy of ultrasound in diagnosing knee joint pathologies using MRI as a reference. Materials And Methods: 50 patients were evaluated prospectively over a period of 1.5 years by USG followed by MRI of the affected knee. Accuracy of USG was calculated with MRI as reference. Results: In our study, the majority of patients were in age group 21-30 years. Perfect agreement was noted between ultrasound and MRI for detecting Baker’s cyst. Near perfect agreement was noted between ultrasound and MRI for detecting joint effusion, soft tissue edema and osteophytes. Substantial agreement was noted between ultrasound and MRI for Collateral ligaments tear and Meniscal injuries. Moderate agreement was noted between ultrasound and MRI for PCL tear. Fair agreement was noted between ultrasound and MRI for ACL tear. Conclusion: Knee USG has high accuracy in diagnosing pathologies like knee joint effusion, synovitis, popliteal/baker’s cysts, soft tissue edema/cellulitis, arthritic changes, collateral ligament and meniscal tears. Keywords: Knee joint pathologies, Ultrasound, MRI, Ligament

Impact of adiabatic logic families on the power-clock generator energy efficiency

Due to the low-power requirement by devices deployed in Near Field Communication (NFC) application operating at low frequencies, adiabatic logic is a good candidate for their implementation and can be used to reduce energy consumption. Adiabatic logic works using an AC power-clock supply. However, generating the AC power-clock increases the energy consumption of the complete adiabatic system. A lot of work has been done on generating the AC power-clocks using resonant circuits and a handful by using the stepwise capacitor based circuit. But the literature lacks the study of the impact of adiabatic logic families’ on the power-clock generator energy dissipation and efficiency. In this paper, we investigate the effect of adiabatic logic families working with 4-phase power-clock generators designed using a 2-StepWise Charging (SWC) circuit. The analysis of the energy dissipation for single power-clock is done taking into account the parasitic resistance and capacitance of the adiabatic logic and power-clock network. Experiments based on simulation results show that the adiabatic logic families’ impacts both the energy consumption and efficiency of the complete adiabatic system

Efficient Retiming of Large Circuits

Retiming, introduced by Leiserson and Saxe, is a powerful transformation of circuits that preserves functionality and improves performance. The ASTRA algorithm proposed an alternative view of retiming using the equivalence between retiming and clock skew optimization, and also presented a fast algorithm for minimum period (minperiod) retiming. Since minperiod retiming may significantly increase the number of flip-flops in the circuit, minimum area (minarea) retiming is an important problem. Minarea retiming is a much harder problem than minperiod retiming, and previous techniques where not capable of handling large circuits in a reasonable time. This work defines the relationship between the Leiserson-Saxe and the ASTRA approaches and utilizes it for efficient minarea retiming of large circuits. The new algorithm, Minaret, uses the same basis as the Leiserson-Saxe approach. The underlying philosophy of the ASTRA approach is incorporated to reduce the number of variables and constraints gener..