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Opcode와 API의 빈도수와 상관계수를 활용한 Cerber형 랜섬웨어 탐지모델에 관한 연구
이계혁,황민채,현동엽,구영인,유동영,Lee, Gye-Hyeok,Hwang, Min-Chae,Hyun, Dong-Yeop,Ku, Young-In,Yoo, Dong-Young 한국정보처리학회 2022 정보처리학회논문지. 컴퓨터 및 통신시스템 Vol.11 No.10
최근 코로나 19 팬더믹 이후 원격근무의 확대와 더불어 랜섬웨어 팬더믹이 심화하고 있다. 현재 안티바이러스 백신 업체들이 랜섬웨어에 대응하고자 노력하고 있지만, 기존의 파일 시그니처 기반 정적 분석은 패킹의 다양화, 난독화, 변종 혹은 신종 랜섬웨어의 등장 앞에 무력화될 수 있다. 이러한 랜섬웨어 탐지를 위한 다양한 연구가 진행되고 있으며, 시그니처 기반 정적 분석의 탐지 방법과 행위기반의 동적 분석을 이용한 탐지 연구가 현재 주된 연구유형이라고 볼 수 있다. 본 논문에서는 단일 분석만을 이용하여 탐지모델에 적용하는 것이 아닌 ".text Section" Opcode와 실제 사용하는 Native API의 빈도수를 추출하고 K-means Clustering 알고리즘, 코사인 유사도, 피어슨 상관계수를 이용하여 선정한 특징정보들 사이의 연관성을 분석하였다. 또한, 타 악성코드 유형 중 웜과 Cerber형 랜섬웨어를 분류, 탐지하는 실험을 통해, 선정한 특징정보가 특정 랜섬웨어(Cerber)를 탐지하는 데 특화된 정보임을 검증하였다. 위와 같은 검증을 통해 최종 선정된 특징정보들을 결합하여 기계학습에 적용하여, 최적화 이후 정확도 93.3% 등의 탐지율을 나타내었다. Since the recent COVID-19 Pandemic, the ransomware fandom has intensified along with the expansion of remote work. Currently, anti-virus vaccine companies are trying to respond to ransomware, but traditional file signature-based static analysis can be neutralized in the face of diversification, obfuscation, variants, or the emergence of new ransomware. Various studies are being conducted for such ransomware detection, and detection studies using signature-based static analysis and behavior-based dynamic analysis can be seen as the main research type at present. In this paper, the frequency of ".text Section" Opcode and the Native API used in practice was extracted, and the association between feature information selected using K-means Clustering algorithm, Cosine Similarity, and Pearson correlation coefficient was analyzed. In addition, Through experiments to classify and detect worms among other malware types and Cerber-type ransomware, it was verified that the selected feature information was specialized in detecting specific ransomware (Cerber). As a result of combining the finally selected feature information through the above verification and applying it to machine learning and performing hyper parameter optimization, the detection rate was up to 93.3%.
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α형 반수석고를 치환한 모르타르의 응결 및 압축강도, 건조수축 특성
이계혁,김규용,이보경,신경수,남정수,Lee, Kye-Hyouk,Kim, Gyu-Yong,Lee, Bo-Kyeong,Shin, Kyoung-Su,Nam, Jeong-Soo 한국구조물진단유지관리공학회 2017 한국구조물진단유지관리공학회 논문집 Vol.21 No.5
${\alpha}$형 반수석고는 생산방법이 복잡하고, 대량 연속 생산이 곤란하며, 재료 단가가 높기 때문에 건설재료로써 활용범위가 크지 않았으나, 최근 화력발전소의 배연탈황석고를 활용하여 경제적으로 ${\alpha}$형 반수석고를 제조하는 기술이 실용화되고 있다. 이에 본 연구에서는 응결 시작 시간이 빠르고 재령 초기 팽창변형이 발생하는 ${\alpha}$형 반수석고의 특징에 주목하여, ${\alpha}$형 반수석고를 10, 20, 30 wt.% 치환한 보통포틀랜드시멘트 및 고로슬래그시멘트 모르타르를 제조한 후 응결 및 압축강도 특성, 건조수축을 검토하였다. 실험 결과, ${\alpha}$형 반수석고의 치환율이 증가할수록 보통포틀랜드시멘트 모르타르 및 고로슬래그시멘트 모르타르의 초결시간이 빨라지는 경향을 확인할 수 있었다. 또한, 보통포틀랜드시멘트 모르타르와 고로슬래그시멘트 모르타르 모두 ${\alpha}$형 반수석고의 치환율이 증가할수록 압축강도가 저하되는 경향을 보였으며, 보통포틀랜드 시멘트보다 고로슬래그시멘트에서 ${\alpha}$형 반수석고의 압축강도 발현이 유리한 것으로 나타났다. 한편, ${\alpha}$형 반수석고를 치환한 모르타르의 경우 ${\alpha}$형 반수석고의 혼입에 의해 생성된 에트링가이트 침상결정의 성장압에 의해 초기재령에서 수축변형이 저감되는 것을 확인할 수 있었으며, 초기 재령에서 수축변형의 억제 효과는 분명하지만, 재령이 지남에 따라 ${\alpha}$형 반수석고를 치환하지 않은 조건과 변형의 차이는 다시 감소하는 경향을 보였다. 따라서 ${\alpha}$형 반수석고를 모르타르에 적용할 경우 강도는 다소 저하하지만, 응결 촉진 및 수축변형 억제에 큰 효과가 있기 때문에 건설재료로써 활용 가치가 높을 것으로 판단된다. In this study, to evaluate the setting time, compressive strength and drying shrinkage of ordinary Portland cement and Portland blast-furnace slag cement mortar with 0, 10, 20, 30 wt.% alpha-calcium sulfate hemihydrate. As a results, as the replacement ratio of alpha-calcium sulfate hemihydrate increased, the initial setting time of ordinary Portland cement and Portland blast-furnace slag cement mortar was faster. In addition, the compressive strength decreased with increasing replacement ratio of alpha-calcium sulfate hemihydrate in both ordinary Portland cement mortar and Portland blast-furnace slag cement mortar. The strength development of Portland blast-furnace slag cement mortar with alpha-calcium sulfate hemihydrate was effective than that of ordinary Portland cement mortar. On the other hand, in the case of the mortar with alpha-calcium sulfate hemihydrate, it was confirmed that shrinkage deformation was reduced at the early age by growth pressure of needle-shaped ettringite crystals produced by incorporation of alpha-calcium sulfate hemihydrate. However, the effect of inhibiting shrinkage deformation of mortar with alpha-calcium sulfate hemihydrate was not significant as the age passed. Therefore, it is considered that the alpha-calcium sulfate hemihydrate is useful as a construction material.
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알파반수석고를 활용한 비소성결합재 기반 바닥 모르타르의 경화특성 및 건조수축 평가
이계혁,김규용,이보경,김래환,신경수 한국건축시공학회 2015 한국건축시공학회지 Vol.15 No.4
Floor mortar experiences dry shrinkage by temperature and humidity difference of internal matrix with materialtype. Also, since floor mortar is influenced by environmental conditions during placing and curing period, cracks arelikely to be occurred. In this study, it was evaluated the hardening and dry shrinkage properties of non-sintered binderbased floor mortar utilizing alpha-hemihydrate gypsum which has expansibility in order to prevent crack of the floormortar. It was applied to the construction site, and examined the effects of external environmental conditions onshrinkage deformation and cracking. Different types of slag accelerated initial and final setting in comparison withcement mortar and its compressive strength was satisfied standard compressive strength for floor mortar. Alsoshrinkage deformation behavior after the initial expansion exhibited a similar tendency with the cement mortar. Fromthe field application result, no crack was found from slag mortar, and it is determined that the slag mortar has betterdimensional stability than cement mortar caused by external environment conditions. 본 연구에서는 바닥 모르타르에 발생하는 균열을 방지하기 위해, 팽창성이 있는 재료인 알파반수석고를 활용한 비소성결합재 기반 바닥 모르타르의 경화특성 및 건조수축 특성을 평가하고, 건설현장에 적용하여 외기환경에 노출된 조건에서 바닥 모르타르의 수축변형 거동 및 균열 발생여부를검토하였다. 그 결과, 슬래그계 바닥 모르타르의 경우 시멘트계 모르타르에 비해 초결 및 종결시간이 급격히 단축되었고 압축강도는 관련기준을 만족하는 것으로 확인되었으며,초기에 팽창 변형 이후의 수축변형 거동은 시멘트계 모르타르와 유사한 경향을 나타내었다. 슬래그계 바닥 모르타르의현장 적용 결과 균열이 발생하지 않았으며, 외기환경 조건에의한 변형률의 차이가 크지 않아 시멘트계 바닥 모르타르에비해 치수안정성이 큰 것으로 판단된다.
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이계혁,임성규,이지연,이소영,이수남,이은주,이지희 대한마취통증의학회 2014 Korean Journal of Anesthesiology Vol.67 No.1
Background: We postulated that palonosetron, a novel antiemetic agent, might have the effect of alleviating injection pain from propofol and rocuronium. A double-blind, controlled study was undertaken to evaluate the effect of palonosetron on injection pain during total intravenous anesthesia and postoperative nausea and vomiting (PONV) using propofol-remifentanil in breast and thyroid cancer surgery. Methods: Sixty patients were randomly allocated to one of two groups. Before injection of propofol and rocuronium, patients in group S (n = 30) received 4 ml of saline and patients in group P (n = 30) received 75 μg (1.5 ml) of palonosetron mixed with 2.5 ml of saline (n = 30). Patients were evaluated by a blinded anesthesiologist with regard to the scoring of injection pain of propofol, withdrawal response by rocuronium, PONV, shivering, postoperative pain, recall of pain, and overall satisfaction. Results: The differences between groups in the incidence of injection pain due to propofol and rocuronium were insignificant. However, in group P, the severity of propofol-induced injection pain (3% vs. 33%, P = 0.003) and postoperative pain (P = 0.038) was significantly lower during the first 12 h after surgery. No differences were observed between the groups with respect to PONV, shivering, recall of pain, and overall satisfaction. Conclusions: We concluded that pretreatment of palonosetron was effective to reduce the severity of propofol-induced injection pain and early postoperative pain, although it did not reduce the incidence of injection pain from propofol and rocuronium.
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조현이,정종철,김호성,최재욱,성대경,서지훈,김성범,이계혁 大韓顎顔面成形再建外科學會 2000 Maxillofacial Plastic Reconstructive Surgery Vol.22 No.1
Osteosarcoma is a primary malignant tumor arising most often in the long bone, but rare in jaw bone. Especially osteogenic sarcoma of the mandible is a rare tumor, comprising less than 0.5% of all head and neck tumors. Osteosarcoma occurs cheifly in young persons, and presenting very survival rates. Histopathologically this tumor can be classified three types, osteoblastic, fibroblastic, chondroblastic and classified from low grade to high grade by anaplasia or mitosis of the tumor cells. Sometimes, the exact diagnosis of osteosarcoma is difficult especially in low grade osteosarcoma, even if clinical or radiographical findings suggest to osteosarcoma. So suspcious to malignant bone tumor in clinical or radiological findings, biopsy should be taked from deep portion and multiple area, and sharing the patient history and radiographs with pathologist will assist in the development of the diagnosis. We report a case of low grade osteosarcoma on the mandible initially difficulty in accurate diagnosis. The patient visited our hospital for routine dental treatment but radiographic findings displayed ill-defined radiolucency with osteoid formation on the mandible. Final diagnosis was difficulty in initial biopsy but subsequent biopsy taked from deep portion presented infiltrative growth and mitosis of the tumor cell in some area with small osteoid bone formation, so we could reach final diagnosis as low grade sarcoma. We treated this patient with bloc resection of the mandible and immediate reconstruction with iliac corticocancellous block.
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