LettuceGDB:The community database for lettuce genetics and omics

As a globally popular leafy vegetable and a representative plant of the Asteraceae family,lettuce has great economic and academic significance.In the last decade,high-throughput sequencing,phenotyping,and other multi-omics data in lettuce have accumulated on a large scale,thus increasing the demand for an integrative lettuce database.Here,we report the establishment of a comprehensive lettuce database,LettuceGDB(https://www.lettucegdb.com/).As an omics data hub,the current LettuceGDB includes two reference genomes with detailed annotations;re-sequencing data from over 1000 lettuce varieties;a collection of more than 1300 worldwide germplasms and millions of accompanying phenotypic records obtained with manual and cutting-edge phenomics technologies;re-analyses of 256 RNA sequencing datasets;a complete miRNAome;extensive metabolite information for representative varieties and wild relatives;epigenetic data on the genome-wide chromatin accessibility landscape;and various lettuce research papers published in the last decade.Five hierarchically accessible functions(Genome,Genotype,Germplasm,Phenotype,and O-Omics)have been developed with a user-friendly interface to enable convenient data access.Eight built-in tools(Assembly Converter,Search Gene,BLAST,JBrowse,Primer Design,Gene Annotation,Tissue Expression,Literature,and Data)are available for data downloading and browsing,functional gene exploration,and experimental practice.A community forum is also available for information sharing,and a summary of current research progress on different aspects of lettuce is included.We believe that LettuceGDB can be a comprehensive functional database amenable to data mining and database-driven exploration,useful for both scientific research and lettuce breeding.

A novel requirement analysis approach for periodic control systems

Periodic control systems （PCSs） are widely used in real-time embedded system domain. However, traditional manual requirement analysis assumes the expert knowledge, which is laborious and error-prone. This paper proposes a novel requirement analysis approach, which supports the automated validation of the informal requirement specifi- cations. Based on the normalized initial requirement docu- ments, our approach can construct an intermediate SPARDL model with both formal syntax and semantics. To check the overall system behaviors, our approach can transform the SPARDL models into executable code for simulation. The derived prototype simulator from SPARDL models enables the testing-based system behavior validation. Moreover, our approach enables the analysis of the dataflow relations in SPARDL models. By revealing input/output and affecting re- lations, our dataflow analysis techniques can help software engineers to figure out the potential data dependencies be- tween SPARDL modules. This is very useful for the module reuse when a new version of the system is developed. A study of our approach using an industry design demonstrates the practicality and effectiveness of our approach.

Semantic theories of programs with nested interrupts

In the design of dependable software for embed- ded and real-time operating systems, time analysis is a cru- cial but extremely difficult issue, the challenge of which is exacerbated due to the randomness and nondeterminism of interrupt handling behaviors. Thus research into a theory that integrates interrupt behaviors and time analysis seems to be important and challenging. In this paper, we present a pro- gramming language to describe programs with interrupts that is comprised of two essential parts： main program and inter- rupt handling programs. We also explore a timed operational semantics and a denotational semantics to specify the mean- ings of our language. Furthermore, a strategy of deriving de- notational semantics from the timed operational semantics is provided to demonstrate the soundness of our operational se- mantics by showing the consistency between the derived de- notational semantics and the original denotational semantics.