http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
김기범,조영호,Kim, Kibeom,Cho, Youngho 한국인터넷정보학회 2022 인터넷정보학회논문지 Vol.23 No.5
Botnets have been exploited for a variety of purposes, ranging from monetary demands to national threats, and are one of the most threatening types of attacks in the field of cybersecurity. Botnets emerged as a centralized structure in the early days and then evolved to a P2P structure. Bitcoin is the first online cryptocurrency based on blockchain technology announced by Satoshi Nakamoto in 2008 and is the most widely used cryptocurrency in the world. As the number of Bitcoin users increases, the size of Bitcoin network is also expanding. As a result, a botnet using the Bitcoin network as a C&C channel has emerged, and related research has been recently reported. In this study, we propose an encrypted botnet C&C communication mechanism and technique in the Bitcoin network and validate the proposed method by conducting performance evaluation through various experiments after building it on the Bitcoin testnet. By this research, we want to inform the possibility of botnet threats in the Bitcoin network to researchers.
학습관리시스템(LMS) 데이터를 활용한 기술수용모형의 사용의도와 실제사용 간의 관계 분석
김기범 ( Kibeom Kim ),차윤미 ( Yoon Mi Cha ),이현우 ( Hyeon Woo Lee ) 한국교육공학회 2019 교육공학연구 Vol.35 No.2
본 연구는 기술수용모형에서 제시하고 있는 사용의도와 실제사용 간의 관계를 실증적으로 검증하기 위해, LMS를 활용하는 학습자의 로그 데이터에 기반해 사용자의 인식과 사용의도가 실제사용에 영향을 미치는 지를 확인하고자 하였다. 연구대상인 A대학교 재학생 1,281명을 대상으로 LMS에 대한 설문조사를 실시하였고, 실제사용 데이터는 LMS에 기록된 로그 중 강의자료, 동영상, 링크, 외부 학습자원 등의 학습자원에 접근한 기록과 게시판, 과제, 퀴즈, 토론, 팀활동 등의 학습활동에서 발생한 기록만 필터링하여 분석에 사용하였다. 실제사용은 강좌별로 교과목 및 교수자의 특성에 따라 교수-학습 활동에 차이가 있으므로 학습자의 로그 데이터의 양을 강좌별로 정규화하고 그 평균값을 사용하였다. 인과관계를 명확히 하기 위해 설문조사 후 그 다음 학기동안 LMS에서 활동한 데이터를 활용하여 구조적 관계를 분석하였다. 연구결과, 학습자의 인지된 용이성, 인지된 유용성, 태도, 사용의도 간의 구조적 관계는 기술수용모형과 일치하는 결과가 도출되었으나, 실제 사용이 포함된 모형은 적합하지 않은 것으로 나타났다. 즉, 사용의도와 실제사용 간 상관관계는 존재하나 사용의도가 실제 사용을 예측하기에는 한계가 있음을 확인하였다. 이를 바탕으로 TAM을 활용한 연구에서 실제 사용에 대한 예측에 주의가 필요함을 논의하였다. The study aims to identify the effects of the user's perception and behavioral intention to use on actual usage based on the log data of LMS in order to empirically verify the relationship between the behavioral intention to use and actual usage of the Technology Acceptance Model. A survey of 1,281 students from A university was conducted on the LMS. Actual usage data were referred to as interaction by filtering data that accessed learning resources including instructional materials, videos, links, and external learning resources among the logs recorded in LMS and data that occurred in learning activities including bulletin board, assignments, quizzes, discussions, and team activities. Because actual usage differed in teaching activities by courses, learners' interaction quantity was normalized by course and the average scores were calculated. To clarify the causal relationship, the structural relationship was analyzed using the data from the LMS during the next semester after the survey. The results show that the structural relationship between learners' perceived ease of use, perceived usefulness, attitudes, and behavioral intention to use has resulted in a consistent result with the TAM, but the model with actual usage is not suitable. In other words, it was confirmed that there is a correlation between intention to use and actual usage, but that intention to use is limited to predicting actual usage. It was discussed that attention should be paid to the prediction of actual usage in conducting research using TAM.
인접 블록 움직임 벡터의 지역적 통계 특성을 이용한 고속 움직임 추정 기법
김기범(Kibeom Kim),정찬영(Chan-Young Jeong),홍민철(Min-Cheol Hong) 한국방송·미디어공학회 2008 방송공학회논문지 Vol.13 No.1
In this paper, we propose a variable step search fast motion estimation algorithm using local statistics of neighboring motion vectors. Using the degree of correlation between neighboring motion vectors, motion search range is adaptively adjusted to reduce unnecessary search points. Based on the adjusted search range, motion vector is obtained by variable search step. Experimental results show that the proposed algorithm has the capability to dramatically reduce the search points and computing cost for motion estimation, comparing to fast full spiral search motion estimation and other fast motion estimation.
AZ61 마그네슘 합금의 어닐링 중 Ca의 첨가에 따른미세조직 변화에 미치는 영향
김기범 ( Kibeom Kim ),전준호 ( Joonho Jeon ),김권후 ( Kwonhoo Kim ) 한국열처리공학회 2021 熱處理工學會誌 Vol.34 No.2
Due to high specific strength and low density, AZ series magnesium alloys have been receiving high interest as a lightweight material. However, their industrial application is limited due to the phenomenon that the strength decreases at elevated temperature by the occurrence of softening effect because of the Mg<sub>17</sub>Al<sub>12</sub> phase decomposition. To solve this problem, many research were conducted to increase the high-temperature strength by forming a thermal stable second-phase component by adding new elements to the AZ magnesium. Especially, adding Ca to AZ magnesium has been reported that Ca forms the new second-phase. However, studies about the analysis of decomposition or precipitation temperature, formation composition, and components to understand the formation behavior of these precipitated phases are still insufficient. Therefore, the effect of Ca addition to AZ61 on the phase change and microstructure of the alloy during annealing was investigated. As a result of analysis of the initial and heat-treated specimen, AZ61 formed α-Mg matrix and precipitated phase of Mg<sub>17</sub>Al<sub>12</sub>, and AZX611 formed one more type of precipitated phase, Al<sub>2</sub>Ca. Also, Al<sub>2</sub>Ca was thermal stable at high temperatures. And after annealing, the laves phase was decomposed to under 10 μm size and distributed in matrix. (Received February 3, 2021; Revised February 10, 2021; Accepted March 17, 2021)