• Journal of KIISE:Computing Practices and Letters
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• v.15 no.11
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• pp.806-818
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• 2009

Since the invention of the integrated circuit (IC) in 1950s, semiconductor technology has undergone dramatic development up to these days. A complete semiconductor is manufactured through a diversity of processes. For better semiconductor productivity, fault detection and classification (FDC) has been rigorously studied for finding faults even before the processes are completed. For FDC, various kinds of sensors are attached in many semiconductor manufacturing devices, and sensor values are collected in a periodic manner. The collection of sensor values consists of sequences of real numbers, and hence is regarded as a kind of time-series data. In this paper, we propose an algorithm for detecting and clustering faults in semiconductor processes. The proposed algorithm is a modification of the existing anomaly detection algorithm dealing with symbolically-represented time-series. The contributions of this paper are: (1) showing that a modification of the existing anomaly detection algorithm dealing with general time-series could be used for semiconductor process data and (2) presenting experimental results for improving correctness of fault detection and clustering. As a result of our experiment, the proposed algorithm caused neither false positive nor false negative.

• Korean Journal of Veterinary Service
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• v.44 no.2
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• pp.73-83
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• 2021

Although many swine farms continuously vaccinated to sow to prevent Porcine epidemic diarrhea(PED), PED has occurred annually in swine herds in Jeonbuk province, Korea. In the present study, the small intestine and feces samples from 17 farms where severe watery diarrhea and death of newborn piglets occurred in 2019 were collected, amplified by RT-PCR and determined the complete nucleotide sequences of the spike (S) glycoprotein genes of nine Jeonbuk PEDV isolates. The spike (S) glycoprotein is an important determinant for molecular characterization and genetic relationship of PEDV. These nine complete S gene isolates were compared with other PEDV reference strains to identify the molecular diversity, phylogenetic relationships and antigenicity analysis. 9 field strains share 98.5~100% homologies with each other at the nucleotide sequence level and 97.3~100% homologies with each other at the amino acid level. The nine Jeonbuk PEDV isolates were classified into G2b group including a genetic specific signal, S-indels (insertion and deletion of S gene). In addition, comparisons the neutralizing epitopes of S gene between 9 field strains and domestic vaccine strains of Korea mutated 12-15 amino acids with SM-98-1 (G1a group) and mutated 0-3 amino acids with QIAP1401 (G2b group). Therefore, the development of G2b-based live vaccines will have to be expedited to ensure effective prevention of endemic PED in Korea. In addition, we will need to be prepared with periodic updates of preventive vaccines based on the PEDV variants for the re-emergence of a virulent strain.