RTL2RTL Formal Equivalence: Boosting the Design Confidence

Increasing design complexity driven by feature and performance requirements and the Time to Market (TTM) constraints force a faster design and validation closure. This in turn enforces novel ways of identifying and debugging behavioral inconsistencies early in the design cycle. Addition of incremental features and timing fixes may alter the legacy design behavior and would inadvertently result in undesirable bugs. The most common method of verifying the correctness of the changed design is to run a dynamic regression test suite before and after the intended changes and compare the results, a method which is not exhaustive. Modern Formal Verification (FV) techniques involving new methods of proving Sequential Hardware Equivalence enabled a new set of solutions for the given problem, with complete coverage guarantee. Formal Equivalence can be applied for proving functional integrity after design changes resulting from a wide variety of reasons, ranging from simple pipeline optimizations to complex logic redistributions. We present here our experience of successfully applying the RTL to RTL (RTL2RTL) Formal Verification across a wide spectrum of problems on a Graphics design. The RTL2RTL FV enabled checking the design sanity in a very short time, thus enabling faster and safer design churn. The techniques presented in this paper are applicable to any complex hardware design.Comment: In Proceedings FSFMA 2014, arXiv:1407.195

Use of Phenomics for Differentiation of Mungbean (Vigna radiata L. Wilczek) Genotypes Varying in Growth Rates Per Unit of Water

In the human diet, particularly for most of the vegetarian population, mungbean (Vigna radiata L. Wilczek) is an inexpensive and environmentally friendly source of protein. Being a short-duration crop, mungbean fits well into different cropping systems dominated by staple food crops such as rice and wheat. Hence, knowing the growth and production pattern of this important legume under various soil moisture conditions gains paramount significance. Toward that end, 24 elite mungbean genotypes were grown with and without water stress for 25 days in a controlled environment. Top view and side view (two) images of all genotypes captured by a high-resolution camera installed in the high-throughput phenomics were analyzed to extract the pertinent parameters associated with plant features. We tested eight different multivariate models employing machine learning algorithms to predict fresh biomass from different features extracted from the images of diverse genotypes in the presence and absence of soil moisture stress. Based on the mean absolute error (MAE), root mean square error (RMSE), and R squared (R2) values, which are used to assess the precision of a model, the partial least square (PLS) method among the eight models was selected for the prediction of biomass. The predicted biomass was used to compute the plant growth rates and water-use indices, which were found to be highly promising surrogate traits as they could differentiate the response of genotypes to soil moisture stress more effectively. To the best of our knowledge, this is perhaps the first report stating the use of a phenomics method as a promising tool for assessing growth rates and also the productive use of water in mungbean crop

Water and nitrogen conditions affect the relationships of Δ13C and Δ18O to gas exchange and growth in durum wheat

Whereas the effects of water and nitrogen (N) on plant Δ13C have been reported previously, these factors have scarcely been studied for Δ18O. Here the combined effect of different water and N regimes on Δ13C, Δ18O, gas exchange, water-use efficiency (WUE), and growth of four genotypes of durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn.] cultured in pots was studied. Water and N supply significantly increased plant growth. However, a reduction in water supply did not lead to a significant decrease in gas exchange parameters, and consequently Δ13C was only slightly modified by water input. Conversely, N fertilizer significantly decreased Δ13C. On the other hand, water supply decreased Δ18O values, whereas N did not affect this parameter. Δ18O variation was mainly determined by the amount of transpired water throughout plant growth (Tcum), whereas Δ13C variation was explained in part by a combination of leaf N and stomatal conductance (gs). Even though the four genotypes showed significant differences in cumulative transpiration rates and biomass, this was not translated into significant differences in Δ18Os. However, genotypic differences in Δ13C were observed. Moreover, ∼80% of the variation in biomass across growing conditions and genotypes was explained by a combination of both isotopes, with Δ18O alone accounting for ∼50%. This illustrates the usefulness of combining Δ18O and Δ13C in order to assess differences in plant growth and total transpiration, and also to provide a time-integrated record of the photosynthetic and evaporative performance of the plant during the course of crop growth

How rising temperatures would be detrimental for cool and warm-season food legumes

Rising temperatures are a major concern for the productivity of food legumes, grown in winter as well as summer-season, especially in tropical and sub-tropical regions. Our studies have indicated marked damage to the reproductive stage, resulting in reduction in pod set and seed yield of chickpea, lentil (cool-season legumes) and mungbean (warm-season legume) under high temperatures. Studies done in controlled and outdoor environments (late sowing) revealed that temperatures >35/20°C (as day and night) were highly detrimental for winter-season legumes; while >38/25°C markedly affected the summer-season legumes (mungbean). Urdbean, (a summer season legume), was found to be relatively more tolerant. The degree of damage varies depending upon the duration, timing and severity of stress. Among the reproductive components, pollen grains were more sensitive, became deformed and showed reduction in pollen viability, reduced germination and pollen tube growth. Stigma receptivity and ovule viability were also inhibited, which affected the pollen germination on stigma surface and restricted tube growth through style, and impaired fertilization to cause flower abortion. Assessment of the physiology of leaves, anthers and styles indicated decrease in sucrose production in all these organs due to inhibition of enzymes, which possibly affected the structural and functional aspects of the pollen grains and tube growth through style. Seed filling is another stage which becomes impaired as a result of inactivation of enzymes related to sucrose production, causing inhibition in sucrose translocation into seeds. Additionally, the composition of the seeds was adversely affected, resulting in small size and poor quality of seeds. The data related to these processes would be presented. Genetic variation for heat tolerance exists in our target legume crops, which needs further probing and use of heat tolerant germplasm in breeding programs. Screening for high temperature tolerance has led to identification of few heat-tolerant genotypes, which are able to maintain their gamete function at high temperature, unlike the sensitive genotypes. Future studies should focus on high throughput phenotyping techniques and/or physiological, biochemical or genetic markers that control the reproductive function. Information about the effects of heat stress on reproductive biology and seed filling events of chickpea, lentil and mungbean will be discussed

Biotic and Abiotic Constraints in Mungbean Production—Progress in Genetic Improvement

Mungbean [Vigna radiata (L.) R. Wilczek var. radiata] is an important food and cash legume crop in Asia. Development of short duration varieties has paved the way for the expansion of mungbean into other regions such as Sub-Saharan Africa and South America. Mungbean productivity is constrained by biotic and abiotic factors. Bruchids, whitefly, thrips, stem fly, aphids, and pod borers are the major insect-pests. The major diseases of mungbean are yellow mosaic, anthracnose, powdery mildew, Cercospora leaf spot, halo blight, bacterial leaf spot, and tan spot. Key abiotic stresses affecting mungbean production are drought, waterlogging, salinity, and heat stress. Mungbean breeding has been critical in developing varieties with resistance to biotic and abiotic factors, but there are many constraints still to address that include the precise and accurate identification of resistance source(s) for some of the traits and the traits conferred by multi genes. Latest technologies in phenotyping, genomics, proteomics, and metabolomics could be of great help to understand insect/pathogen-plant, plant-environment interactions and the key components responsible for resistance to biotic and abiotic stresses. This review discusses current biotic and abiotic constraints in mungbean production and the challenges in genetic improvement

Food Legumes and Rising Temperatures: Effects, Adaptive Functional Mechanisms Specific to Reproductive Growth Stage and Strategies to Improve Heat Tolerance

Ambient temperatures are predicted to rise in the future owing to several reasons associated with global climate changes. These temperature increases can result in heat stress- a severe threat to crop production in most countries. Legumes are well-known for their impact on agricultural sustainability as well as their nutritional and health benefits. Heat stress imposes challenges for legume crops and has deleterious effects on the morphology, physiology, and reproductive growth of plants. High-temperature stress at the time of the reproductive stage is becoming a severe limitation for production of grain legumes as their cultivation expands to warmer environments and temperature variability increases due to climate change. The reproductive period is vital in the life cycle of all plants and is susceptible to high-temperature stress as various metabolic processes are adversely impacted during this phase, which reduces crop yield. Food legumes exposed to high-temperature stress during reproduction show flower abortion, pollen and ovule infertility, impaired fertilization, and reduced seed filling, leading to smaller seeds and poor yields. Through various breeding techniques, heat tolerance in major legumes can be enhanced to improve performance in the field. Omics approaches unravel different mechanisms underlying thermotolerance, which is imperative to understand the processes of molecular responses toward high-temperature stress

Evaluation of interfacial frictional resistance

Three distinct mechanisms-sliding, bonding and bearing - for the mobilisation of interfacial friction have been identified. In the light of these mechanisms, the effect of variation in reinforcement parameters, such as extensibility, flexibility and hardness on mobilisation of interfacial friction, and the mechanisms themselves has been examined. The influence of boundary effects of apparatus on the interfacial friction has been discussed and a method of estimating the same in a pull-out box has been proposed

Evaluation of interfacial frictional resistance

Three distinct mechanisms — sliding, bonding and bearing — for the mobilisation of interfacial friction have been identified. In the light of these mechanisms, the effect of variation in reinforcement parameters, such as extensibility, flexibility and hardness on mobilisation of interfacial friction, and the mechanisms themselves has been examined. The influence of boundary effects of apparatus on the interfacial friction has been discussed and a method of estimating the same in a pull-out box has been proposed

Technique for Using Fine-Grained Soil in Reinforced Earth

The performance of reinforced earth structures depends on the mobilization of interfacial shearing resistance between soil and reinforcement. This criterion typically eliminates the use of fine-grained soil as a backfill material in reinforced earth structures. Considering the distribution of induced interfacial shear stress in soil around the surface of the reinforcement, it has been shown that only a thin zone of frictional material around the reinforcement is required to mobilize almost full interfacial shearing resistance of sand. Six series of pullout tests have been conducted, with different types of reinforcement, to study the effect of thickness of sand (frictional material) around the reinforcement on the pullout resistance. Sawdust and kaolin clay have been used as bulk backfill material, providing the soil with negligible friction. With low-friction-strength soil as bulk material, a 15-mm thickness of sand around the reinforcement is required to increase the interfacial shearing resistance to that with sand as the bulk material. With this new technique, low-frictional fine-grained soils can be used as bulk backfill material in reinforced earth constructions