Functional Verification for Agile Processor Development: A Case for Workflow Integration

Agile hardware development methodology has been widely adopted over the past decade.Despite the research progress,the industry still doubts its applicability,especially for the functional verification of complicated processor chips.Functional verification commonly employs a simulation-based method of co-simulating the design under test with a reference model and checking the consistency of their outcomes given the same input stimuli.We observe limited collaboration and information exchange through the design and verification processes,dramatically leading to inefficiencies when applying the conventional functional verification workflow to agile development.In this paper,we propose workflow integration with collaborative task delegation and dynamic information exchange as the design principles to effectively address the challenges on functional verification under the agile development model.Based on workflow integration,we enhance the functional verification workflows with a series of novel methodologies and toolchains.The diff-rule based agile verification methodology(DRAV)reduces the overhead of building reference models with runtime execution information from designs under test.We present the RISC-V implementation for DRAV,DiffTest,which adopts information probes to extract internal design behaviors for co-simulation and debugging.It further integrates two plugins,namely XFUZZ for effective test generation guided by design coverage metrics and LightSSS for efficient fault analysis triggered by co-simulation mismatches.We present the integrated workflows for agile hardware development and demonstrate their effectiveness in designing and verifying RISC-V processors with 33 functional bugs found in NutShell.We also illustrate the efficiency of the proposed toolchains with a case study on a functional bug in the L2 cache of XiangShan.

Pigeon Robot for Navigation Guided by Remote Control:System Construction and Functional Verification

Animal robots have outstanding advantages over traditional robots in their own energy supplies,orientation,and natural concealment,delivering significant value in the theories and applications of neural science,national security,and other fields.Presently,many animal robots have been fabricated,but researches about the applications of avian robots are still lacking.In this study,we constructed a Pigeon Robot System(PRS),optimized the electric stimulation parameters,assessed the electric stimulus of navigation,and evaluated the navigation efficiency in the field.Biphasic pulse constant current pattern was adapted,and the optimal stimulus parameters of 4 nuclei tested were of amplitude 0.3 mA,5 pulse trains,frequency 25 Hz,5 pulses,and a 25%duty cycle.Effective ratio of left and right steering behavior response to electric stimulus dorsointermedius ventralis anterior nuclei was 67%and 83%,respectively(mean value 75%).Electrical stimulation efficiency was 0.34-0.68 and path efficiency was 0.72-0.85 among pigeon robot individuals in the open field.Neither electrical stimulation efficiency nor path efficiency differed significantly(P>0.05),suggesting that the navigational PRS performance was not biased in either direction.PRS can achieve continuous navigation along simple pathways and provide the necessary application infrastructure and technical reference for the development of animal robot navigation technology.

Functional analysis of the nitrogen metabolism-related gene CsGS1 in cucumber

Glutamine synthetase(GS)plays an important role in nitrogen(N)metabolism in cucumber.In this study,we cloned and sequenced the CsGS1 gene,and analyzed the expression patterns and subcellular localization of the GS1 protein in response to different N conditions in order to determine its role in low-nitrogen(LN)tolerance.CsGS1 was abundantly expressed in the leaves of the low N-requiring cultivar D0328,while the high N-requiring cultivar D0422 showed similar expression levels across different tissues including leaves,shoots and roots.Furthermore,the GS1 protein was primarily localized in the cytoplasm of plant cells.Both cultivars were then transformed with the CsGS1 coding sequence or antisense sequence via Agrobacterium tumefaciens in order to overexpress and silence GS1 expression,respectively.Overexpression of CsGS1 significantly improved LN tolerance and photosynthetic parameters,and increased chlorophyll b content,biomass,plant height,root length,N accumulation and GS activity under LN condition compared to the control.CsGS1 silencing on the other hand significantly reduced the above indices.Taken together,CsGS1 is crucial for maintaining N metabolism in cucumber plants during N deprivation,and is a promising target for generating novel transgenic breeds with increasing nitrogen utilization efficiency.

Transcriptome Analysis and Genes Function Verification of Root Development of Paeonia suffruticosa under Sandy Loam Cultivation

Relatively poor in vitro rooting has limited the large-scale commercial production of tree peony.In this study,on the basis of transcriptome sequencing,differentially expressed genes and the associated metabolic pathways were identified in tree peony roots at different stages of root formation under sandy loam cultivation.A total of 31.63 Gb raw data were generated and 120,188 unigenes(mean length of 911.98 bp)were annotated according to six databases(NR,NT,GO,KEGG,COG,and Swiss-Prot).Analyses of the ungerminated root primordium period,induced root primordium period,and root formation period detected 8,232,6,907,and 10,687 differentially expressed genes related to 133,132,and 133 metabolic pathways,respectively.Two significantly differentially expressed genes(Unigene13430_All and CL10096.Contig1_All)were associated with the auxin pathway.The full-length Unigene13430_All coding sequence(843 bp)encoded 280 amino acids,whereas the full-length CL10096.Contig1_All coding sequence(1,470 bp)encoded 489 amino acids.Unigene13430_All and CL10096.Contig1_All were identified as IAA gene family members and were respectively named PsIAA27 and PsARF19.The qRT-PCR analysis and functional verification indicated that the expressions of PsARF19 and PsIAA27 in tree peony seedlings,cuttings and grafted seedlings were significant different.PsARF19 promoted root development,it might be a regulatory gene related to the formation of tree peony roots,while PsIAA27 inhibited lateral root development,and it might be involved in controlling auxin sensitivity during root formation.The results of this study may form the basis of future investigations on the mechanism mediating peony root formation.The transcriptome data will be an excellent resource for researchers interested in characterizing the rooting-related tree peony genes.

Safety Design and Verification Analysis in the Satellite Development Stage

A safety design applies to every stage in a satellite system development life cycle to identify and analyze hazards in the satellite at a system level, eliminating or controlling various safety risks, while verifying the functions of the satellite system have safety characteristics, so as to optimize the satellite system for the best performance in terms of time and cost. This article comprehensively leverages such factors as satellite reliability, complexity and life cycle by considering the overall satellite safety work plan, hazard analysis, hazard sources, pyrotechnic devices and other module safety critical designs. Safety design measures were formulated to review and verify the effectiveness of system functions including a safe power supply to a satellite and pyrotechnic explosives to achieve the safety requirements of the satellite from a development stage. Safety design activities for each subsystem will ensure meeting the development requirements of the satellite system as a whole, and ensure the satellite system cannot be the cause of casualties, equipment damage, property loss, or have a health-threatening impact or detrimental impact on the environment.

Genome-wide association studies reveal the genetic basis of amino acid content variation in tea plants

Tea is one of the most popular non-alcoholic beverages in the world,and free amino acids,especially theanine,make a major contribution to the umami taste of tea.However,the genetic basis of the variation in amino acid content in tea plants remains largely unknown.Here,we measured the free amino acid content in fresh leaves of 174 tea accessions over two years using a targeted metabolomics approach and obtained genotype data via RNA sequencing.Genome-wide association studies were conducted to investigate loci affecting the content of free amino acids.A total of 69 quantitative trait loci(–log10(P-value)>5)were identified.Functional annotation revealed that branched-chain amino acid aminotransferase,glutamine synthetase,nitrate transporter,and glutamate decarboxylase might be important for amino acid metabolism.Two significant loci,glutamine synthetase(Glu1,P=3.71×10^(−4);Arg1,P=4.61×10^(−5))and branched-chain amino acid aminotransferase(Val1,P=4.67×10^(−5);I_Leu1,P=3.56×10^(−6)),were identified,respectively.Based on the genotyping result,two alleles of CsGS(CsGS-L and CsGS-H)and CsBCAT(CsBCAT-L and CsBCAT-H)were selected to perform function verification.Overexpression of CsGS-L and CsGS-H enhanced the contents of glutamate and arginine in transgenic plants,and overexpression of CsBCAT-L and CsBCAT-H promoted the accumulation of valine,isoleucine and leucine.Enzyme activity assay uncovered that SNP1054 is important for CsGS catalyzing glutamate into glutamine.Furthermore,CsGS-L and CsGS-H differentially regulated the accumulation of glutamine,and CsBCAT-L and CsBCAT-H differentially regulated the accumulation of branched-chain amino acids.In summary,the findings in our study would provide new insights into the genetic basis of amino acids contents variation in tea plants and facilitate the identification of elite genes to enhance amino acids content.

Optimization of Callus Induction Conditions from Immature Embryos in Maize and Plant Regeneration

This research uses the immature embryos of inbred maize lines(GSH9901,Hi01,Hi02,and Chang 7-2)as receptor materials to establish the callus induction system.These inbred lines provide the receptor materials for the genetic regeneration of maize and the verification of the genetic functions of maize.The factor experiment and orthogonal experiments were used to investigate the impacts of different genotypes,immature embryo size,shield orientation,2,4-D concentration,proline concentration,and folic acid concentration on the induction rate of embryogenic callus tissue.A sensitivity experiment testing glyphosate(Bar)and an antibiotic(Cefotaxime sodium)were also conducted.The results indicate that the immature embryos of inbred maize line GSH9901 were the most effective for callus tissue induction,and the immature embryos with a length of 1.6-2.0 mm produce the best result.The upward shield face is more successful for the formation of induced callus.Using orthogonal analysis,we found that the optimal combination for the induction system was A_(3)(2,4-D concentration 0.25 mg mL^(-1)),B_(1)C_(3)(proline concentration 0.8 mg mL^(-1)),and D 2(folate Concentration 0.5 mg mL^(-1))and the induction rate reached 84%.We found that cold storage at 4℃ for 1 d is more conducive for the formation of embryogenic callus than the other treatments tested.The sensitivity experiment for callus tissue screening revealed the critical concentration of glyphosate to be 10 mg ml^(-1),and the critical concentration of antibiotic is 250 mg ml^(-1).Using this combination of glyphosate and antibiotic resulted in regenerated plants.This study established the optimal conditions for immature embryo callus tissue induction in maize.

Automatic Circuit Extractor for HDL Description Using Program Slicing

Design extraction and reduction have been extensively used in modern VLSI design process. The extracted and reduced design can be efficiently processed by various applications, such as formal verification, simulation, automatic test pattern generation (ATPG), etc. This paper presents a new circuit extraction method using program slicing technique, and develops an elegant theoretical basis based on program slicing for circuit extraction from Verilog description. The technique can obtain a chaining slice for given signals of interest. Compared with related researches, the main advantages of the method include that it is fine grain, it has no hardware description language (HDL) coding style limitation; it is precise and is capable of dealing with various Verilog constructions. The technique has been integrated with a commercial simulation environment and incorporated into a design process. The results of practical designs show the significant benefits of the approach.