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As the complexity of design and fabrication for instrumentation-on-silicon systems increases, the optimization of a combined Built-In Self-Test (BIST) and Automated Test Equipment (ATE) process is desirable to meet the high fault coverage while preserving acceptable costs. For digital systems, the costs associated with a combined BIST/ATE testing process mainly consist of the following components: 1) the cost due to the BIST area overhead and 2) the cost due to the overall test time. In general, BIST is faster than ATE, but it can provide only a limited fault coverage; for attaining a higher fault coverage from BIST, additional area (at a corresponding higher cost) is required. However, a higher fault coverage can usually be achieved from ATE, but excessive use of ATE results in additional test time (as an increased cost). The fault coverage of BIST and ATE plays a significant role, because it can affect the area overhead in BIST and the test time in BIST/ATE. This paper proposes a novel numerical method to find the optimized fault coverage by BIST and ATE so that minimal cost can be achieved. The proposed method is then applied to two parallel combined BIST/ATE testing schemes to ensure its validity

Background Nowadays, PRRS has become one of the most economically important infectious diseases of pig worldwide. To better characterize and understand the molecular basis of PRRSV virulence determinants, it would be important to develop the infectious cDNA clones. In this regard, HuN4-F112, a live-attenuated North-American-type PRRSV vaccine strain, could serve as an excellent model. Results In the study, genomic sequence of HuN4-F112, an attenuated vaccine virus derived from the highly pathogenic porcine reproductive and respiratory syndrome virus (PRRSV) HuN4 strain, was determined and its full-length cDNA was cloned. Capped RNA was transcribed in vitro from the cDNA clone and transfected into BHK-21 cells. The supernatant from transfected monolayers were serially passaged in Marc-145 cells. The rescued virus exhibited a similar growth pattern to its parental virus in Marc-145 cells with peak titers at 48 h post-infection. Conclusion In conclusion, we rescued virus from an infectious cDNA clone of attenuated vaccine. It is possible in the future that a new attenuated PRRSV vaccine with broader specificity and good immunogenicity can be designed in vitro via an infectious cDNA clone platform coupled with validated information on virulence determinants.

Background The regions in the middle of nonstructural protein 2 (nsp2) of porcine reproductive and respiratory syndrome virus (PRRSV) have been shown to be nonessential for PRRSV replication, and these nonessential regions are different in various viral strains. Finding In this study, the nonessential regions of the nsp2 of an attenuated vaccine strain (HuN4-F112) of highly pathogenic porcine reproductive and respiratory syndrome virus were identified based on an infectious cDNA clone of HuN4-F112. The results demonstrated that the segments of nsp2 [amino acids (aa) 480 to 667] tolerated deletions. Characterization of the mutants demonstrated that those with small deletions did not affect the viral growth on Marc-145 cells, but deletion of these regions led to earlier PRRSV replication increased (before 36 h after infectious in vitro). Conclusion The functional roles of nsp2 variable middle region for PRRSV HuN4-F112 replication have been identified. Our results also suggested that none-essential region might be an ideal insertion region to express foreign gene in PRRSV genome.