An Experimental Study of Reduced-Voltage Operation in Modern FPGAs for Neural Network Acceleration

We empirically evaluate an undervolting technique, i.e., underscaling the circuit supply voltage below the nominal level, to improve the power-efficiency of Convolutional Neural Network (CNN) accelerators mapped to Field Programmable Gate Arrays (FPGAs). Undervolting below a safe voltage level can lead to timing faults due to excessive circuit latency increase. We evaluate the reliability-power trade-off for such accelerators. Specifically, we experimentally study the reduced-voltage operation of multiple components of real FPGAs, characterize the corresponding reliability behavior of CNN accelerators, propose techniques to minimize the drawbacks of reduced-voltage operation, and combine undervolting with architectural CNN optimization techniques, i.e., quantization and pruning. We investigate the effect of environmental temperature on the reliability-power trade-off of such accelerators. We perform experiments on three identical samples of modern Xilinx ZCU102 FPGA platforms with five state-of-the-art image classification CNN benchmarks. This approach allows us to study the effects of our undervolting technique for both software and hardware variability. We achieve more than 3X power-efficiency (GOPs/W) gain via undervolting. 2.6X of this gain is the result of eliminating the voltage guardband region, i.e., the safe voltage region below the nominal level that is set by FPGA vendor to ensure correct functionality in worst-case environmental and circuit conditions. 43% of the power-efficiency gain is due to further undervolting below the guardband, which comes at the cost of accuracy loss in the CNN accelerator. We evaluate an effective frequency underscaling technique that prevents this accuracy loss, and find that it reduces the power-efficiency gain from 43% to 25%.Comment: To appear at the DSN 2020 conferenc

Comparison of Intraperitoneal Honey and Sodium Hyaluronate-Carboxymethylcellulose (Seprafilm™) for the Prevention of Postoperative Intra-Abdominal Adhesions

BACKGROUND: Abdominal surgery can lead to postoperative intra-abdominal adhesions (PIAAs) with significant morbidity and mortality. This study compares the use of honey with a standard bioresorbable membrane (Seprafilm tm) to prevent the formation of PIAAs in rats. METHODS: Thirty rats underwent laparotomy, and PIAAs were induced by scraping the cecum. The animals were divided into three groups, each containing ten rats. Group 1 (control) represented the cecal abrasion group, with no intraperitoneal administration of any substance. Group 2 (honey group) underwent cecal abrasion and intraperitoneal administration of honey. Group 3 (Seprafilm tm group) underwent cecal abrasion and intraperitoneal Seprafilm tm application. RESULTS: Group 1 exhibited higher adhesion scores for adhesions between the abdominal wall and the organs. Groups 2 and 3 had decreased adhesive attachments to the intra-abdominal structures. Compared to group 1, the incidence of adhesion formation was lower in both group 2 (p=0.001) and group 3 (p=0.001). The incidence of fibrosis was also lower in group 2 (p=0.016) and group 3 (p=0.063) compared to group 1. There was no significant difference between the histopathological fibrosis scores for the rats in group 2 and those in group 3 (p= 0.688). CONCLUSION: This study suggests that both honey and Seprafilm tm decrease the incidence of PIAAs in the rat cecal abrasion model. Although the mechanism of action is not clear, intraperitoneal administration of honey reduced PIAAs. The outcome of this study demonstrates that honey is as effective as Seprafilm tm in preventing PIAAs

MoRS: An approximate fault modelling framework for reduced-voltage SRAMs

On-chip memory (usually based on Static RAMs-SRAMs) are crucial components for various computing devices including heterogeneous devices, e.g, GPUs, FPGAs, ASICs to achieve high performance. Modern workloads such as Deep Neural Networks (DNNs) running on these heterogeneous fabrics are highly dependent on the on-chip memory architecture for efficient acceleration. Hence, improving the energy-efficiency of such memories directly leads to an efficient system. One of the common methods to save energy is undervolting i.e., supply voltage underscaling below the nominal level. Such systems can be safely undervolted without incurring faults down to a certain voltage limit. This safe range is also called voltage guardband. However, reducing voltage below the guardband level without decreasing frequency causes timing-based faults. In this paper, we propose MoRS, a framework that generates the first approximate undervolting fault model using real faults extracted from experimental undervolting studies on SRAMs to build the model. We inject the faults generated by MoRS into the on-chip memory of the DNN accelerator to evaluate the resilience of the system under the test. MoRS has the advantage of simplicity without any need for high-time overhead experiments while being accurate enough in comparison to a fully randomly-generated fault injection approach. We evaluate our experiment in popular DNN workloads by mapping weights to SRAMs and measure the accuracy difference between the output of the MoRS and the real data. Our results show that the maximum difference between real fault data and the output fault model of MoRS is 6.21%, whereas the maximum difference between real data and random fault injection model is 23.2%. In terms of average proximity to the real data, the output of MoRS outperforms the random fault injection approach by 3.21x.This work is partially funded by Open Transprecision Computing (OPRECOM) project, Summer of Code 2020.Peer ReviewedPostprint (author's final draft

Comparison of intraperitoneal honey and sodium hyaluronate-carboxymethylcellulose (SeprafilmTM) for the prevention of postoperative intra-abdominal adhesions

BACKGROUND: Abdominal surgery can lead to postoperative intra-abdominal adhesions (PIAAs) with significant morbidity and mortality. This study compares the use of honey with a standard bioresorbable membrane (Seprafilm tm) to prevent the formation of PIAAs in rats. METHODS: Thirty rats underwent laparotomy, and PIAAs were induced by scraping the cecum. The animals were divided into three groups, each containing ten rats. Group 1 (control) represented the cecal abrasion group, with no intraperitoneal administration of any substance. Group 2 (honey group) underwent cecal abrasion and intraperitoneal administration of honey. Group 3 (Seprafilm tm group) underwent cecal abrasion and intraperitoneal Seprafilm tm application. RESULTS: Group 1 exhibited higher adhesion scores for adhesions between the abdominal wall and the organs. Groups 2 and 3 had decreased adhesive attachments to the intra-abdominal structures. Compared to group 1, the incidence of adhesion formation was lower in both group 2 (p=0.001) and group 3 (p=0.001). The incidence of fibrosis was also lower in group 2 (p=0.016) and group 3 (p=0.063) compared to group 1. There was no significant difference between the histopathological fibrosis scores for the rats in group 2 and those in group 3 (p= 0.688). CONCLUSION: This study suggests that both honey and Seprafilm tm decrease the incidence of PIAAs in the rat cecal abrasion model. Although the mechanism of action is not clear, intraperitoneal administration of honey reduced PIAAs. The outcome of this study demonstrates that honey is as effective as Seprafilm tm in preventing PIAAs

MoRS: An approximate fault modelling framework for reduced-voltage SRAMs

On-chip memory (usually based on Static RAMs-SRAMs) are crucial components for various computing devices including heterogeneous devices, e.g, GPUs, FPGAs, ASICs to achieve high performance. Modern workloads such as Deep Neural Networks (DNNs) running on these heterogeneous fabrics are highly dependent on the on-chip memory architecture for efficient acceleration. Hence, improving the energy-efficiency of such memories directly leads to an efficient system. One of the common methods to save energy is undervolting i.e., supply voltage underscaling below the nominal level. Such systems can be safely undervolted without incurring faults down to a certain voltage limit. This safe range is also called voltage guardband. However, reducing voltage below the guardband level without decreasing frequency causes timing-based faults. In this paper, we propose MoRS, a framework that generates the first approximate undervolting fault model using real faults extracted from experimental undervolting studies on SRAMs to build the model. We inject the faults generated by MoRS into the on-chip memory of the DNN accelerator to evaluate the resilience of the system under the test. MoRS has the advantage of simplicity without any need for high-time overhead experiments while being accurate enough in comparison to a fully randomly-generated fault injection approach. We evaluate our experiment in popular DNN workloads by mapping weights to SRAMs and measure the accuracy difference between the output of the MoRS and the real data. Our results show that the maximum difference between real fault data and the output fault model of MoRS is 6.21%, whereas the maximum difference between real data and random fault injection model is 23.2%. In terms of average proximity to the real data, the output of MoRS outperforms the random fault injection approach by 3.21x.This work is partially funded by Open Transprecision Computing (OPRECOM) project, Summer of Code 2020.Peer ReviewedPostprint (author's final draft

Maternal Height and Infant Body Mass Index Are Possible Risk Factors for Developmental Dysplasia of the Hip in Female Infants

Developmental dysplasia of the hip (DDH) is a wide-spectrum disease with a multifactorial etiology and, despite its prevalence, no definitive etiology has yet been established. The aim of this study was to investigate new risk factors for DDH by evaluating newly defined potential risk factors. A total of 71 infants were separated into 2 groups:Group I, 28 female first-born infants diagnosed with DDH and their mothers;and Group II, 43 healthy female first-born infants and their mothers. The maternal height and weight before pregnancy, infant height and weight at birth, and body mass index (BMI) of both mother and infant were determined. Calculations were made of the ratios between these parameters. Of the examined risk factors, only maternal height and the ratio of maternal height to infant BMI (MH/I-BMI) were found to be significant for DDH in infants. In conclusion, the results of this study show that a short maternal height and a low MH/I-BMI increase the risk of DDH. Further studies with a larger series are necessary to confirm these results

Protective effect of thymoquinone on smoking-induced vascular damage: An experimental study in rats

Aim: To investigate the protective effect of thymoquinone on smoking-induced vascular damage in rats. Method: A total of 28 rats were allocated in this experimental study. Rats were equally divided in four groups; as control group (n=7) and study groups including only smoking group (n=7), smoking plus thymoquinone group (n=7) and smoking plus dexamethasone group (n=7). The animals in study groups were subjected to regular cigarette smoke exposure during 2 months, hereby smoking-induced vascular injury model was established in the animals. The thoracic aorta of the animals were surgically resected and then evaluated histopathologically. The prepared aortic tissue samples were analyzed under light microscope in terms of thickness of aortic wall, endothelial continuity and injury as well as degenerative alterations on the endothelium. Results: Mean aortic wall thicknesses were 77.8 and 114.5 μ in only smoking group and smoking plus thymoquinone group respectively, and this difference was statistically significant. In only smoking group partial endothelial damage and complete endothelial damage were observed in 2 and 4 animals respectively whereas in smoking plus thymoquinone group no endothelial damage and partial endothelial damage were observed in 2 and 4 animals respectively. When these groups were compared in terms of endothelial damage, the difference was detected to be statistically significant. Conclusion: Our study demonstrates that thymoquinone has a protective effect on rat endothelium and alleviates the smoking-induced vascular damage in rats

Bilateral Transverse (Bowdler) Fibular Spurs with Hypophosphatasia in an Adolescent Girl

Hypophosphatasia is a clinically heterogeneous inheritable disorder characterized by defective bone mineralization and the deficiency of serum and tissue liver/bone/kidney alkaline phosphatase activities. Due to the mineralization defect of the bones, various skeletal findings can be radiologically observed in hypophosphatasia. Bowing and Bowdler spurs of long bones are the characteristic findings. The Bowdler spurs reported on in the previous pertinent literature were observed in the perinatal aged patients and these lesions have rarely involved adolescents. We herein report on a 14-year-old girl with fibular Bowdler spurs

The efficacy of multiparametric prostate magnetic resonance imaging in the diagnosis and treatment of prostate cancer

Aim: To investigate the accuracy of multiparametric prostate magnetic resonance imaging (mpMRI) in determining the diagnosis and treatment options of prostate cancer (PCa), and its pathology correlation. Methods: Between October 2017 and January 2018, 73 patients were subjected to an mpMRI at our clinic. Of these patients, 11 were radical prostatectomy (RP) after treatment, and four were post- radiation therapy (RT) follow-up. The remaining 58 patients were assigned to the PSA elevation and / or positive digital rectal examination (DRE) patient group in this study and their outcomes were evaluated. Results: Of the 58 patients included in the study, 13 were found to have a PI-RADS 5 on mpMRI and in 9 (90%) of 10 patients undergoing simultaneous biopsy, PCa was detected. The biopsy results of all cases evaluated as PI-RADS 1 were benign. All of the patients who were ISUP 3 and above had a PI-RADS 5. Patients with a PI-RADS score of 4 and above being ISUP 2 and above was statistically significant (p=0.011). A case had undergone a previous radical prostatectomy assessment revealed that tPSA increased to 2 ng/ml during the follow-up, and so RT was added to the treatment; although LAP was identified in the left iliac region on an mpMRI performed upon the continued increase of tPSA. During the follow-ups of the patient who had regional RT, the tPSA dropped below 0.01 ng/ml. Conclusion: The results of our study show that mpMRI can gain a new and important place in urology due to the guidance it provides in biopsies, facilitating targeted biopsy, its effectiveness in determining treatment modalities and its importance in post-PCa treatment follow-ups