사전기반으로 압축된 텍스트에 대한 압축패턴매칭

허성찬,조석현,심정섭 한국차세대컴퓨팅학회 2016 한국차세대컴퓨팅학회 논문지 Vol.12 No.1

압축패턴매칭문제는 원본 텍스트 T 를 압축한 압축 텍스트 Z 와 찾으려는 패턴 P 가 주어질 때, T 안에 발생하는 모든 P 의 위치를 찾는 문제이다. 본 논문에서는 LZ78 알고리즘이나 LZW 알고리즘과 같이 사전을 기반으로 압축된 텍스트에 대한 Boyer-Moore-Horspool 기반의 압축패턴매칭문제를 해결하는 알고리즘을 제시한다. 또한, 기존의 압축패턴매칭 알고리즘들의 문자 비교 순서를 변경한 알고리즘들을 제시한다. 다양한 수행시간 비교 실험을 통해 알파벳의 크기와 같은 텍스트의 특성에 따라 가장 효과적인 압축패턴매칭 알고리즘이 달라질 수 있음을보인다. Given a pattern P and a compressed text Z generated from a text T , the compressed pattern matching problem is to find all occurrences of pattern P in T , using P and Z . We present an algorithm for the compressed pattern matching problem based on the Boyer-Moore-Horspool algorithm when text T is compressed by dictionary-based compression algorithms such as LZ78 or LZW compression. We also present modified algorithms changing orders of character comparisons for previous compressed pattern matching algorithms. Then we show, by various experiments, that the most effective compressed pattern matching algorithms can be different according to properties of texts such as the size of alphabets.

연소기 노즐목부 내피 벌징 공정 설계

허성찬,류철성,이금오,최환석 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.11

한국형발사체 3단 엔진용 7톤급 연소기 노즐목부 내피를 벌징시켜 외피와 브레이징 접합하기 적합한 외피의 형상을 도출하였다. 이를 위하여 자유확관 형태의 다단 벌징 치구 설계와 이에 대한 일련의 성형 해석을 수행하고 최종 벌징 후 노즐목 형상과 비교하였다. 성형 해석 결과로부터 노즐목 영역에 미성형 부위가 존재하는 것을 확인하였으며 형상 오차 보정을 통하여 외피의 형상을 수정하였다. 보정 설계된 외피 형상에 대한 2차 성형 해석을 통해 노즐목부 내피가 치구와의 간극 없이 적절히 성형됨을 확인하였다. An outer jacket shape for brazing with a bulged inner liner used in the 7-tonf class thrust chamber of the KSLV-Ⅱ third stage engine has been designed. Design of the forming tools for multi-stage free bulging process and a series of numerical simulation had been carried out to verify the shape difference between the outer jacket and formed inner liner. From the result, undeformed region was observed near the nozzle throat and the shape difference has been compensated by considering the gap distribution between the inner liner and the final stage bulging tool. Subsequential simulations using the modified model had been conducted and it was confirmed that the shape deviation of the deformed nozzle was properly compensated without any gaps.

Morphological and molecular characterization of root-lesion nematode Pratylenchus hippeastri from Korea

허성찬,박남숙,강헌일,배창환,최인수 한국환경생물학회 2023 환경생물 : 환경생물학회지 Vol.41 No.4

The root-lesion nematode Pratylenchus spp. is the most important plantparasitic nematode due to its worldwide distribution, wide host ranges, and migratory endoparasitic characteristics. One population of Pratylenchus collected from the giant pussy willow (Salix chaenomeloides Kimura) in the Andong area as part of a nematode survey in Korea was characterized morphologically and by molecular methods. The analysis of morphological measurements and morphometric characteristics, as well as DNA sequencing of the rRNA large subunit (LSU) D2/D3 expansion segments and the internal transcribed spacer (ITS) gene sequence, confirmed the identity of this population as P. hippeastri. This study is the first report of P. hippeastri associated with Salix chaenomeloides in Korea and worldwide. Further studies on distribution and pathogenicity in different P. hippeastri host crops, such as grapevines, strawberries, and apples, are necessary. The taxonomic keys to 16 Pratylenchus species in Korea are provided.

임금근로자에서 저녁근무 횟수에 따른 우울, 불안 및 피로와의 관련성

허성찬,조윤래,이승호,최홍석,전만중,이종영 대한직업환경의학회 2020 대한직업환경의학회 학술대회 논문집 Vol.2020 No.11

다점무금형성형기술의 항공기 스킨 성형 적용 연구

허성찬,서영호,구태완,김정,강범수 한국항공우주학회 2007 한국항공우주학회 학술발표회 논문집 Vol.- No.-

국내 관엽식물 및 작물재배지의 식물기생선충 발생 조사

허성찬,박남숙,김용철,최인수,Sungchan Huh,Namsook Park,Yongchul Kim,Insoo Choi 한국식물병리학회 2023 식물병연구 Vol.29 No.4

정서적 안정과 휴식에 효과적이며, 공기 정화 등 기능성을 가진 관엽식물에 대한 수요가 증가하고 있으나, 관엽식물에 피해를 유발할 수 있는 식물기생선충에 대한 연구는 전무한 실정이다. 본 연구는 국내 판매되고 있는 관엽식물에서 발생하는 식물기생선충의 검출 여부와 밀도를 파악하고자 관엽식물과 작물재배지에 대해 2022년 7월부터 12월까지 모니터링을 수행하였다. 415개의 관엽식물과 국내 24개 차나무 및 22개 감귤재배지의 식물기생선충을 조사하였다. 관엽식물 내 식물기생선충 조사 결과, 뿌리썩이선충이 가장 많이 검출되었으며, 잎선충, 뿌리혹선충, 침선충이 확인되었다. 차나무재배지에서는 나선선충, 씨스트선충, 뿌리혹선충, 뿌리썩이선충이 검출되었고, 감귤재배지에서는 감귤선충, 주름선충, 뿌리썩이선충, 뿌리혹선충 등이 검출되었다. 관엽식물, 차나무 및 감귤 재배지에서 뿌리썩이선충이 가장 우려되는 식물기생선충이었으나, 뿌리혹선충, 씨스트선충이 일부 검출되어 피해가 우려되므로 온탕침법, 유기농업자재의 사용, 잡초제거 등 식물기생선충의 방제 방법을 재배에 적용하여야 할 것이다. This study was conducted to investigate the plant-parasitic nematodes of ornamental foliage plants, citrus orchards, and tea plantations from July to December 2022. As a result of the investigation of plant-parasitic nematodes in 415 foliage plants, root-lesion nematodes were detected most frequently, followed by root-knot nematodes, pin nematodes, and other nematodes. In tea plantations, spiral nematodes, cyst nematodes, and root-knot nematodes were detected. Citrus nematodes, ring nematodes, and root-knot nematodes were discovered in citrus orchards. In foliage plants, tea plantations, and citrus orchards, the detection rate of plant-parasitic nematodes was not high, but root-lesion nematodes were detected. Therefore, it is necessary to apply appropriate control methods to manage root-lesion nematodes during the cultivation of foliage, tea, and citrus plants.

주름판 재생냉각채널 구조의 성형해석 및 성형성 검토

허성찬,유철성,이금오,곽준영,최환석 한국항공우주학회 2014 한국항공우주학회 학술발표회 논문집 Vol.2014 No.11

발사체용 엔진 연소기의 확대노즐부 재생냉각채널을 주름판 구조로 제작하기 위한 성형공정을 검토하였다. 스탬핑, 판재액압성형, 다단굽힘공정에 대하여 적합성을 검토하기 위한 성형해석을 수행하였다. 재생냉각채널 구조에서 균일한 두께 분포를 확보하는데 소재의 유입량이 미치는 영향을 확인하였다. 성형해석 결과로부터 다단굽힘공정이 두께 균일성 및 성형성 측면에서 가장 적합한 공정임 확인하였다. 축방향으로 곡면을 갖는 확대노즐부 형상에 의한 길이방향에서의 성형성을 조사하기 위하여 3차원 해석을 수행하였다. 축방향 위치에 따라 변형률 분포는 유사한 경향을 보였으나 소재 유입률의 차이가 발생하였다. 따라서 확대노즐부 제작 적용 시 분할 제작을 고려해야 할 것으로 판단된다. Sheet metal forming processes for a corrugated type regenerative cooling channel structure of the extended nozzle used in a launch vehicle engine have been studied. Numerical simulations of stamping, sheet hydroforming and multi-stage bending processes for a single channel structure had been carried out to verify the effect of the material feeding on the thickness uniformity. The multi-stage bending process showed the most appropriate result in view of thickness distribution and formability. Three dimensional simulation of the multi-stage bending process had been conducted to verify the forming effect of the curved shape along the axial direction of the nozzle on the formability. Similar strain distributions were observed in several sections along the direction although difference was shown in material feeding ratio. Therefore, sectional manufacturing and subsequent welding processes should be considered to produce the extended nozzle.

제3차 - 6차 근로환경조사를 이용한 우리나라 제조업 근로자의 작업관련 요통유병의 시계열추이 및 관련 요인

허성찬,박진욱,양선희 한국산업보건학회 2022 한국산업보건학회지 Vol.32 No.4

Objective: This study was to perform to identify the distribution characteristics and related factors of work-related low back pain among manufacturing workers in Korea. Methods: We analyzed the third(2011) through sixth(2020) Korean Working Conditions Survey. This study examined changes in the prevalence of work-related low back pain among manufacturing workers and related factors, including demographic characteristics and working conditions. Results: The prevalence of work-related low back pain showed a general tendency to increase during the study periods except for the 5th wave. The prevalence of work-related low back pain was higher in women than in men. The prevalence increased with increasing age and decreased with higher educational attainment. This trend was observed in all survey waves. The prevalence ratios for work-related low back pain according to working conditions varied over the survey period. In general, workers with manual jobs, long working hours, and exposure to tired or painful postures showed relatively higher prevalence ratios than did their counterparts. Providing Information on health and safety, perception that work affects health, and experience of presenteeism were identified as influencing factors for work-related low back pain. Although the working environment is improving, work-related back pain is on the rise. A multifaceted study on risk factors for work-related low back pain is needed. Conclusion: Work-related low back pain is a significant factor affecting the working population's quality of life. The prevalence of work-related low back pain showed a tendency to increase during the study periods. A multifaceted study on risk factors for work-related low back pain is needed.

임금금로자의 저녁 근무 횟수와 정신건강의 관련성: 우울, 불안을 중심으로

허성찬,조윤래,이승호,전만중 대한직업환경의학회 2021 대한직업환경의학회 학술대회 논문집 Vol.2021 No.11

하이드로포밍 부품의 성형성 평가기준 적용 연구

허성찬,송우진,구태완,김정,강범수 대한기계학회 2007 大韓機械學會論文集A Vol.31 No.8

In tube hydroforming process, several defective products could be obtained such as bursting, wrinkling, folding, buckling. Because, especially, bursting is most frequently occurred failure among the well known failures, it is mostly important to predict the onset of bursting failure on tube hydroforming process. For most sheet metal forming processes, strain based forming limit diagram(FLD) is used often as a criteria to estimate the possibility of onset of the failures proposed above. However, FLD has a shortcoming that it is dependent on strain path while stress based diagram is independent on strain history. Generally, tube hydroforming consists of three main processes such as pre-bending, pre-forming, and hydroforming and it means that the strain histories of final products are nonlinear. Therefore, forming limit stress diagram(FLSD) is more suitable to predict forming limit for hydroforming parts. In this study, FLSD is applied to estimate bursting failure for an engine cradle of an automobile part. Consequently, it is proved that application of FLSD to predict forming limit is available for tube hydroforming parts.