Real-Time Dense Stereo Matching With ELAS on FPGA Accelerated Embedded Devices

For many applications in low-power real-time robotics, stereo cameras are the sensors of choice for depth perception as they are typically cheaper and more versatile than their active counterparts. Their biggest drawback, however, is that they do not directly sense depth maps; instead, these must be estimated through data-intensive processes. Therefore, appropriate algorithm selection plays an important role in achieving the desired performance characteristics. Motivated by applications in space and mobile robotics, we implement and evaluate a FPGA-accelerated adaptation of the ELAS algorithm. Despite offering one of the best trade-offs between efficiency and accuracy, ELAS has only been shown to run at 1.5-3 fps on a high-end CPU. Our system preserves all intriguing properties of the original algorithm, such as the slanted plane priors, but can achieve a frame rate of 47fps whilst consuming under 4W of power. Unlike previous FPGA based designs, we take advantage of both components on the CPU/FPGA System-on-Chip to showcase the strategy necessary to accelerate more complex and computationally diverse algorithms for such low power, real-time systems.Comment: 8 pages, 7 figures, 2 table

R3^3SGM: Real-time Raster-Respecting Semi-Global Matching for Power-Constrained Systems

Stereo depth estimation is used for many computer vision applications. Though many popular methods strive solely for depth quality, for real-time mobile applications (e.g. prosthetic glasses or micro-UAVs), speed and power efficiency are equally, if not more, important. Many real-world systems rely on Semi-Global Matching (SGM) to achieve a good accuracy vs. speed balance, but power efficiency is hard to achieve with conventional hardware, making the use of embedded devices such as FPGAs attractive for low-power applications. However, the full SGM algorithm is ill-suited to deployment on FPGAs, and so most FPGA variants of it are partial, at the expense of accuracy. In a non-FPGA context, the accuracy of SGM has been improved by More Global Matching (MGM), which also helps tackle the streaking artifacts that afflict SGM. In this paper, we propose a novel, resource-efficient method that is inspired by MGM's techniques for improving depth quality, but which can be implemented to run in real time on a low-power FPGA. Through evaluation on multiple datasets (KITTI and Middlebury), we show that in comparison to other real-time capable stereo approaches, we can achieve a state-of-the-art balance between accuracy, power efficiency and speed, making our approach highly desirable for use in real-time systems with limited power.Comment: Accepted in FPT 2018 as Oral presentation, 8 pages, 6 figures, 4 table

The low abundance of CpG in the SARS-CoV-2 genome is not an evolutionarily signature of ZAP

The zinc finger antiviral protein (ZAP) is known to restrict viral replication by binding to the CpG rich regions of viral RNA, and subsequently inducing viral RNA degradation. This enzyme has recently been shown to be capable of restricting SARS-CoV-2. These data have led to the hypothesis that the low abundance of CpG in the SARS-CoV-2 genome is due to an evolutionary pressure exerted by the host ZAP. To investigate this hypothesis, we performed a detailed analysis of many coronavirus sequences and ZAP RNA binding preference data. Our analyses showed neither evidence for an evolutionary pressure acting specifically on CpG dinucleotides, nor a link between the activity of ZAP and the low CpG abundance of the SARS-CoV-2 genome

Room temperature texturing of austenite/ferrite steel by electropulsing

The work reports an experimental observation on crystal rotation in a duplex (austenite + ferrite) steel induced by the electropulsing treatment at ambient temperature, while the temperature rising due to ohmic heating in the treatment was negligible. The results demonstrate that electric current pulses are able to dissolve the initial material’s texture that has been formed in prior thermomechanical processing and to produce an alternative texture. The results were explained in terms of the instability of an interface under perturbation during pulsed electromigation

Effect of Salicylic Acid Foliar Application on Physiological Indices and Induction of Terminal Heat Stress Tolerance of Quinoa in Ahvaz

IntroductionQuinoa (Chenopodium quinoa L.) is a dicotyledonous, allotetraploid, three-carbon, annual, optional salt-loving plant and is native to South America and the Andean highlands. The growth period of the plant varies between 70 and 240 days depending on the cultivated area. The main product of this plant is the seed, which has a high nutritional value in terms of protein, amino acid balance, unsaturated fat, vitamins, and minerals. Like other plants, quinoa faces various environmental stresses during its growth period, and its growth and yield are a function of environmental factors and their mutual effects. The occurrence of high temperatures during the sensitive stages of plant growth, such as flowering and seed formation, may cause a significant decrease in quinoa yield, and high temperature has been cited as one of the most important challenges for the cultivation and expansion of quinoa in the world. Salicylic acid acts as a signal molecule and plays an important role in regulating growth and development processes in plants under environmental stress. Salicylic acid increases the content of relative humidity, accumulation of dry matter, and the amount of chlorophyll.Materials and MethodsThe objective of this research is to assess the physiological responses of quinoa cultivars to varying planting dates and the impact of foliar application of salicylic acid in mitigating the adverse effects of end-of-season heat stress during the 2021-2022 crop year. The study was conducted at the research farm of the Faculty of Agriculture, Shahid Chamran University of Ahvaz, using a split-split plot design within a randomized complete block framework, with three replications. In this experiment, three factors a) planting date including October 12, November 11, and December 11, and b) foliar application of salicylic acid in the two stages of budding and the beginning of flowering including non-application, 1.5 mM and 3 mM and c) Quinoa cultivars including Titicaca, Giza, Q12 and Redcarin were investigated.Results and DiscussionThe effect of investigated factors such as planting date, salicylic acid, and variety on different traits had statistically significant differences. The results showed that the maximum amount of stomatal conductance and the relative content of leaf water belonged to the date of October 12. The highest biological yield and seed yield were observed under conditions of application of 1.5 and 3 mM salicylic acid, respectively. Probably, salicylic acid has increased the growth and accumulation of dry matter by improving carbon fixation, synthesis of metabolites, and maintaining the water status of plant tissues. Based on the results of the comparison of the mean of the three-way interaction, the maximum amount of biological yield and seed as the most important goals of quinoa plant cultivation, respectively, in the treatment of not using salicylic acid in the Redcarin cultivar on the planting date of December 11 and the application of 3 mM salicylic acid was obtained in the variety Redcarin on the planting date of October 12. The highest rate of net assimilation and the growth rate of the product belonged to the treatments of no application of salicylic acid in the Redcarin cultivar on December 11 and no application of salicylic acid in the Giza cultivar on October 12, respectively. The treatment of not using salicylic acid in the Redcarin variety on the planting date of October 12 was also able to achieve a high harvest index.Conclusion According to the obtained results, it seems that to achieve a high seed yield of quinoa, it is possible to benefit from the treatment of 3 mM salicylic acid in the Redcarin variety on the planting date of October 12

Electric-field-induced alignment of electrically neutral disk-like particles: modelling and calculation

This work reveals a torque from electric field to electrically neutral flakes that are suspended in a higher electrical conductive matrix. The torque tends to rotate the particles toward an orientation with its long axis parallel to the electric current flow. The alignment enables the anisotropic properties of tiny particles to integrate together and generate desirable macroscale anisotropic properties. The torque was obtained from thermodynamic calculation of electric current free energy at various microstructure configurations. It is significant even when the electrical potential gradient becomes as low as 100 v/m. The changes of electrical, electroplastic and thermal properties during particles alignment were discussed

Nano-mechanical properties of Fe-Mn-Al-C lightweight steels

High Al Low-density steels could have a transformative effect on the light-weighting of steel structures for transportation and achieving the desired properties with the minimum amount of Ni is of great interest from an economic perspective. In this study, the mechanical properties of two duplex low-density steels, Fe-15Mn-10Al-0.8C-5Ni and Fe-15Mn-10Al-0.8C (wt.%) were investigated through nano-indentation and simulation through utilization of ab initio formalisms in Density Functional Theory (DFT) in order to establish the hardness resulting from two critical structural features (ߢ-carbides and B2 intermetallic) as a function of annealing temperature (500 − 1050 ℃) and the addition of Ni. In the Ni-free sample, the calculated elastic properties of kappa-carbides were compared with those of the B2 intermetallic Fe3Al − L12, and the role of Mn in the kappa structure and its elastic properties were studied. The Ni-containing samples were found to have a higher hardness due to the B2 phase composition being NiAl rather than FeAl, with Ni-Al bonds reported to be stronger than the Fe-Al bonds. In both samples, at temperatures of 900 ℃ and above, the ferrite phase contained nano-sized discs of B2 phase, wherein the Ni-containing samples exhibited higher hardness, attributed again to the stronger Ni-Al bonds in the B2 phase. At 700 ℃ and below, the nano-sized B2 discs were replaced by micrometre sized needles of kappa in the Ni-free sample resulting in a lowering of the hardness. In the Ni-containing sample, the entire alpha phase was replaced by B2 stringers, which had a lower hardness than the Ni-Al nano-discs due to a lower Ni content in B2 stringer bands formed at 700 ℃ and below. In addition, the hardness of needle-like kappa-carbides formed in alpha phase was found to be a function of Mn content. Although it was impossible to measure the hardness of cuboid kappa particles in gamma phase because of their nano-size, the hardness value of composite phases, e.g. gamma + kappa was measured and reported. All the hardness values were compared and rationalized by bonding energy between different atoms

Electropulse-induced microstructural evolution in a ferritic–pearlitic 0.14% C steel

The present work reports the experimental observation of electropulse-induced microstructural evolution in a ferritic–pearlitic steel at ambient temperature. Electropulsing initially causes the fragmentation of lamellar structure. Further treatment leads to the formation of new cementite plates aligned with the current direction. This is attributed to the reduction of the system free energy. The hardness of the material decreased with an increase in the number of electric current pulses. Electrical resistivity is thought to be responsible for the observed phenomenon