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

Trace determination of bisphenol-A in landfill leachate samples by dispersive liquid- liquid microextraction followed by high performance liquid chromatography

A simple, rapid and efficient sample pretreatment technique, termed dispersive liquid-liquid microextraction (DLLME), was developed as an extraction methodology to determine bisphenol-A (BPA), in landfill leachate samples prior to high performance liquid chromatography (HPLC)-ultraviolet detection. Some effective parameters, such as pH, extraction and disperser solvent type and their volumes, time of extraction and salt effect have been optimized using the one-factor-at-a-time approach. Under the optimum conditions, the preconcentration factor 25 was obtained from only 5 mL of the sample. The calibration graph was linear in the range of 5-500 µg L-1 with the detection limit of 1.5 µg L-1. The relative standard deviation (RSD) for ten replicate measurements of 20 µg L-1 of BPA was 2.5%. Finally, the method was successfully applied for the extraction and determination of BPA in some landfill leachate samples with a relative recovery of 98–109% and RSD less than 5%. KEY WORDS: Dispersive liquid-liquid microextraction, Bisphenol-A, Landfill leachate samples, High-performance liquid chromatography Bull. Chem. Soc. Ethiop. 2014, 28(3), 329-338.DOI: http://dx.doi.org/10.4314/bcse.v28i3.

Glutathione Peroxidase Activity Assay with Colorimetric Method and Microplate Reading Format and Comparison with Chemiluminescence Method

Glutathione peroxidase (GPX) has a key role in the protection of organisms from oxidative damage. Many diseases and disorders are associated with changes in GPX activity. Therefore, its activity assay can be crucial in prevention, diagnosis and treatment of them. Several companies produce GPX activity assay kit but it is being imported to Iran which is expensive and time-consuming. This research has been done to investigate a simple, rapid and inexpensive method for GPX activity assay. In this study, GPX reduced cumene hydroperoxide while oxidized glutathione (GSH) to GSSG. The generated GSSG was reduced to GSH with consumption of NADPH by glutathione reductase. The decrease of NADPH absorption which was proportional to GPX activity measured at 340 nm with microplate reading format. Sensitivity, precision and accuracy have been examined. The results obtained by the colorimetric method compared with chemiluminescence method and correlation coefficient has been determined. Sensitivity of this method was 15 mU/ml. The coefficient of variation percent for intra and inter assay was less than 9.7 %. According to parallelism and recovery tests, ratio % and recovery %  ranged from 91% to 112% and correlation coefficient between the two methods was 0.9898 (n=60). Data from this study showed that the method has an acceptable sensitivity, precision and accuracy and can be suitable for both clinical and research studies. Indeed, this study is the first step of domestic commercial kit production purpose

Anti-amnesic activity of Citrus aurantium flowers extract against scopolamine-induced memory impairments in rats

Alzheimer's disease (AD) is a progressive neurological disorder that mostly affects the elderly population. Learning and memory impairment as the most characteristic manifestation of dementia could be induced chemically by scopolamine, a cholinergic antagonist. Cholinergic neurotransmission mediated brain oxidative stress. Citrus aurantium (CA) has traditionally been used for the treatment of insomnia, anxiety and epilepsy. The present study was designed to investigate the effect of Citrus aurantium on scopolamine-induced learning and memory deficit in rats. Forty-two Wistar rats were divided into six equal groups. (1) Control (received saline), (2) SCOP (scopolamine at a dose of 1 mg/kg for 15 days), (3) and (4) SCOP + CA (scopolamine and CA extract at doses of 300 and 600 mg/kg per day for 15 days), (5) and (6) intact groups (CA extract at 300 and 600 mg/kg per day for 15 days, respectively). Administration of CA flower extract significantly restored memory and learning impairments induced by scopolamine in the passive avoidance test and also reduced escape latency during trial sessions in the Morris water maze test. Citrus aurantium flower extract significantly decreased the serum malondialdehyde (MDA) levels. Citrus aurantium flower extract has repairing effects on memory and behavioral disorders produced by scopolamine and may have beneficial effects in the treatment of AD

Evaluation of Waterlogging Tolerance in Twenty-One Cultivars and Genotypes of Bread Wheat (Triticum Aestivum L.) and its Effect on some Physiological Characteristics of Shoot and Root System at the Three-Leaf Stage

IntroductionCovering a staggering 215 million hectares, wheat stands as the world's most extensively cultivated crop plant. Just like its botanical counterparts, wheat operates as an obligate aerobic organism, implying its reliance on absorbing oxygen from the surrounding environment to facilitate growth, proliferation, and the successful completion of its life cycle. Annual instances of waterlogging stress inflict harm upon wheat crops, attributed to inadequate irrigation practices, subpar drainage systems, uneven field leveling, elevated groundwater levels, the presence of unyielding impermeable layers, and bouts of intense, abrupt rainfall. This adverse impact is progressively escalating, potentially influenced by the ongoing shifts in climate patterns. Consequently, the adoption of resilient cultivars and the genetic enhancement of bread wheat assume critical importance. These strategies are aimed at augmenting the wheat's capacity to effectively cope with waterlogging stress, aligning it with the mounting demands of a burgeoning global population.To achieve these goals, it is necessary to understand the factors causing waterlogging stress damage in wheat and to know the mechanisms of tolerance in this plant. The survival of root terminal meristem cells under waterlogging stress conditions is very limited, and their ability to grow again after removing the stress is also restricted. Waterlogging stress leads to the death of primary roots and reduced growth of lateral roots in wheat. However, there is variation among wheat cultivars concerning these traits. Reduced access to oxygen hampers root growth and nutrient absorption, including nitrogen. Consequently, photosynthesis and carbohydrate availability decrease, further restricting root growth.Materials and MethodsAn outdoor pot experiment was conducted to investigate the effect of waterlogging stress on shoot and root dry matter, as well as some physiological characteristics. The experiment followed a split-plot design based on randomized complete blocks with three replications. The stress was applied at the three-leaf stage, and three control levels were used: no waterlogging stress, mild stress (48 hours of waterlogging stress), and severe stress (120 hours of waterlogging stress) as the main factors. Cultivars and genotypes were also included as secondary factors.During the stress period, the water level was maintained at approximately 5 cm above the soil level. The cultivation took place outdoors in plastic pots. Data analysis was performed using SAS software, and graphs were generated using Excel software. Comparisons between treatments were based on the standard error. After testing different models, the linear regression model was ultimately employed.Results and DiscussionMild and severe waterlogging stress resulted in a significant decrease in shoot dry matter of 14.06% and 38.37%, respectively, across all cultivars and genotypes. Different cultivars and genotypes exhibited varying responses to waterlogging stress. To further understand the reasons for these differences, among the 21 cultivars and genotypes, Mehrgan and Sarang cultivars, as well as ms 93-16 and ms 93-6 genotypes, were selected due to their contrasting tolerance levels and yield potential. These selected cultivars and genotypes were studied to analyze specific root traits.Amidst severe waterlogging stress, a significant 38% reduction in root dry matter and a corresponding 29% decrease in root volume were recorded when compared to stress-free conditions. This closely mirrored the decline evident in shoot dry matter. Evaluation of the susceptibility index during the three-leaf stage unveiled that sole resilience was exhibited by the Aflak cultivar. In contrast, the remaining cultivars and genotypes were stratified into semi-tolerant and semi-susceptible categories.Notably, regression analysis underscored that even brief periods of waterlogging stress ushered in a reduction in dry matter. Furthermore, the elongation of the waterlogging duration magnified this decrease in dry matter, thereby mitigating the disparities across various cultivars and genotypes.ConclusionIn general, cultivars that were able to sustain higher levels of photosynthetic activity during waterlogging stress demonstrated a lower percentage decrease in dry matter. Although the Mehrgan cultivar experienced a significant reduction in dry matter yield and fell into the semi-sensitive group, it consistently exhibited significantly higher dry matter yield compared to other cultivars and genotypes across all treatments.AcknowledgmentThe authors express their gratitude to the Agriculture Research Center of Khuzestan for providing the seeds, the Research Vice-Chancellor of the Shahid Chamran University of Ahvaz for covering the costs, and all the employees of the Department of Plant Production and Genetics

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