시스템콜 시퀀스 추출 프레임워크를 이용한 시퀀스 기반 컨테이너 보안 강화 기법의 정량적 분석 연구

송소민,김유양,탁병철 한국정보과학회 2023 정보과학회논문지 Vol.50 No.11

Container escape is one of the most critical threats in containerized applications that share a host kernel. Attackers exploit kernel vulnerabilities through a series of manipulated system calls to achieve privilege escalation, which can lead to container escape. Seccomp is a security mechanism widely used in containers. It strengthens the level of isolation by filtering out unnecessary system call invocations. However, the filtering mechanism of Seccomp that blocks individual system calls has a fundamental limitation in that it can be vulnerable to attacks that use system calls allowed by the policy. Therefore, this study presents a hybrid analysis framework that combines static and dynamic analyses to extract system call sequences from exploit codes. Using this framework, we compared the security strength of an existing individual system call-based filtering mechanism and proposed a system call sequence-based filtering mechanism in terms of the number of blockable exploit codes using system call profiles for the same exploit codes. As a result, the proposed system call sequence-based filtering mechanism was able to increase the defense coverage from 63% to 98% compared to the existing individual system call-based filtering mechanism.

패킷형 데이터를 위한 저전력 전송방법

윤명철 대한전자공학회 2004 電子工學會論文誌-SD (Semiconductor and devices) Vol.41 No.7

패킷형 데이터전송은 다량의 데이터가 연속적으로 전달되는 특성이 있다. 이와 같은 데이터를 버스를 통하여 전송할 패에 데이터의 전송순서는 버스의 전력소모에 영향을 주는 하나의 요소로서 작용한다. 본 논문에서는 패킷형 데이터를 전송할 때 데이터의 전송순서를 변화시켜 버스의 전이횟수를 줄임으로써 버스의 소비전력을 감소시키는 순서변환코딩 (Sequence-Switch Coding, SSC)을 제안하였다. 또한 SSC를 구현하는 알고리즘을 개발하였으며, 실험을 통하여 이들 알고리즘으로 기존의 널리 알려진 Bus-Invert Coding보다 우수한 성능을 얻을 수 있음을 보였다. SSC는 버스의 소비전력을 줄이는 하나의 방법이며, 이를 실현하는 알고리즘은 무수히 많다. 알고리즘의 다양성은 SSC가 갖는 하나의 장점으로써 회로설계자에게 버스의 소비전력과 회로의 구현부담 사이에서 넓은 범위에 걸쳐 절충할 수 있는 자유를 제공해 준다. Packet-type data transmission is characterized by the continuous transmission of massive data with relatively constant rate. In such transmission, the dynamic power consumed on buses is influenced by the sequence of transmitted data. A new coding scheme called Sequence-Switch Coding (SSC) is proposed in this paper. SSC reduces the number of bus transitions in the transmission of packet-type data by changing the sending order of the data. Some simple algorithms are presented, In. The simulation results show that SSC outperforms the well-known Bus-Invert Coding with these algorithms. SSC is not a specific algerian but a method to reduce the number of bus-transitions. There could be lots of algorithms for realizing SSC. The variety of SSC algorithms provides circuit designers a wide range of trade-off between performance and circuit complexity.

역타공법 중심의 골조 공기단축을 위한 시공시퀀스 변경에 따른 구조해석 및 요소기술 분석

박용현,주영규 대한건축학회 2019 大韓建築學會論文集 : 構造系 Vol.35 No.6

The purpose of this study is to improve a general Top-Down construction process for superstructure construction period reduction. In ageneral Top-Down construction sequence, the ground floor slab is set up first. Subsequently, 1st basement level construction including corewalls is constructed. Initiation of the ground level superstructure gets waited until then. In this study, removable deck plate installation on thebottom of the core walls of ground level is preceding the concrete casting, therefore, ground level superstructure construction is able to getstarted earlier. Up to first typical floor concrete casting, total of seventy-two working(calendar) days will be resulted in a reduction from thetotal construction periods. 이 연구의 목적은 도심지공사 역타공법(Full Top-Down) 적용사례를 중심으로 골조 공기단축을 위해 기존의 일반적인 골조시공순서 변경함에 따른 구조해석 및 고려해야 할 요소기술을 분석하고 골조공기단축에 대한 정량적인 평가하기 위함이다. 기존의 일반적인 역타공법은 구조적인 이유로 시공기준층인 1층바닥 콘크리트타설 이후 지하1층 슬래브 골조공사 및 지하1층 코아벽체 및 기둥 RC공사를 선행 공사한 후 지상층 골조공사를 착수해야 한다. 지상층 골조공사 착수는 지하 1개층 토공사 및 골조공사 기간 만큼 지연되게 된다. 본 연구는 시공기준층 골조공사 직후 지하층과 동시에 지상층 코아벽체등 골조공사를 착수하기 위해서 코아내부 탈형데크 슬래브, 개구부부위등의 임시 슬래브 콘크리트 타설등을 계획하였다. 지하1개층 코아벽체를 폐합이전에 지상 5개층 코아벽체 선행시공에 따른 시공단계별 구조해석 분석하고 골조공기에 대한 모니터링 결과 72일의 지상층 골조공기를 단축할 수 있다.

상업용 설비 부하의 중성선 영상전류 저감장치 분석 및 적용에 관한 연구

김경철,이일무,백승현,Kim, Kyung-Chul,Lee, Il-Moo,Paik, Seung-Hyun 한국조명전기설비학회 2004 조명·전기설비학회논문지 Vol.18 No.5

현대 사회 전반에 걸쳐 개인용 컴퓨터와 같은 비선형 부하가 증가하여, 중성선에는 많은 고조파 전류가 흐른다. 3상 4선식 배전계통을 채용하는 중성선에 과다한 고조파 전류가 흐르면 여러 가지 고조파 장해를 일으킨다. 중성선 고조파 저감 대책으로 지그재그 변압기를 이용하는 영상 필터가 널리 쓰이고 있다. 본 논문에서는 상용화된 중성선 영상 전류 저감장치를 분석하고, 고조파를 저감시키기 위해서 상업용 설비 부하에 적용하고자 한다. 실측한 값과 MATLAB으로 시뮬레이션 한 값을 수치와 그래프로 비교해 보았다. With the proliferation of nonlinear loads such as commercial facilities in all of modern society high neutral harmonic currents have been observed. High neutral currents in three-phase four-wire distribution systems can cause lots of harmonic problems. The most common solution of neutral harmonic currents reduction is a zero phase sequence filter using zig-zag transformer. This paper analyzes a commercially available neutral line zero sequence currents reduction device and applies the equipment to commercial office loads for eliminating harmonics. Experimental results m compared numerically and graphically with simulation results through the use of MATLAB.

조명부하의 중성선 영상전류 저감장치 분석 및 적용에 관한 연구

김경철,이일무,정영호,백승현,Kim, Kyung-Chul,Lee, Il-Moo,Jung, Yung-Ho,Paik, Seung-Hyun 한국조명전기설비학회 2004 조명·전기설비학회논문지 Vol.18 No.3

With the proliferation of nonlinear loads such as lighting facilities in all modern society high neutral harmonic currents have been observed. High neutral currents in three- phase four-wire distribution systems can cause lots of harmonic problems. The most common solution of neutral harmonic currents reduction is a zero phase sequence filter using zig-zag transformer. This paper analyzes a commercially available neutral line zero sequence currents reduction device and applies the equipment to lighting loads for eliminating harmonics. Experimental results are compared numerically and graphically with simulation results through the use of MATLAB. 현대 사회 전반에 걸쳐 조명설비와 같은 비선형 부하가 증가하여, 중성선에는 많은 고조파 전류가 흐른다. 3상 4선식 배전계통을 채용하는 중성선에 과다한 고조파 전류가 흐르면 여러 가지 고조파 장해를 일으킨다. 중성선 고조파 저감 대책으로 지그재그 변압기를 이용하는 영상 필터가 널리 쓰이고 있다. 본 논문에서는 상용화된 중성선 영상 전류 저감장치를 분석하고, 고조파를 저감시키기 위해서 조명 부하에 적용하고자 한다. 실측한 값과 MATLAB으로 시뮬레이션한 값을 수치와 그래프로 비교해 보았다.

ORP profile을 이용한 연속 회분식 반응기(Sequencing Batch Rector)에서 무산소공정 추론

심문용,부경민,임정훈,우혜진,김창원 한국환경과학회 2004 한국환경과학회지 Vol.13 No.3

The SBR(Sequencing Batch Reactor) process is ideally suited to treat high loading wastewater due to its high dilution rate. SBR operates by a cycle of periods consisting of filling, reacting, settling, decanting and idling. The react phases such as aeration or non-aeration, organic oxidation, nitrification, denitrification and other biological reactions can be achieved in a reactor. Although the whole reactions can be achieved in a SBR with time distributing, it is hard to manage the SBR as a normal condition without recognizing a present state. The present state can be observed with nutrient sensors such as NH₄^(-)-N, NO₂^(-)-N, NO₃^(-)-N and PO₄^(3-)-P. However, there is still a disadvantage to use the nutrient sensors because of their high expense and inconvenience to manage. Therefore, it is very useful to use common on-line sensors such as DO, ORP and pH, which are less expensive and more convient. Moreover, the present states and unexpected changes of SBR might be predicted by using of them. This study was conducted to get basic materials for making an inference of SBR process from ORP(oxidation reduction potential) of synthetic wastewater. The profiles of ORP, DO, and pH were under normal nitrification and denitrification were obtained to compare abnormal condition. And also, nitrite and nitrate accumulation were investigated during reaction of SBR. The bending point on ORP profile was not entirely in the low COD/NOx ratio condition. In this case, NOx was not entirely removed, and minimum ORP value was presented over -300mV. Under suitable COD/NOx ratio which complete denitrification was achieved, ORP bending point was observed and minimum ORP value was under -300mV. Under high COD/NOx ratio, ORP bending point was not detected at the first subcycle because of the fast denitrification and minimum ORP value was under -300mV at the time.

보조선을 사용하지 않은 Sequence Switch Coding 회로의 설계

윤명철(Myungchul Yoon) 大韓電子工學會 2009 電子工學會論文誌-SD (Semiconductor and devices) Vol.46 No.11

코딩정보의 전송을 위하여 보조선에서 발생하는 오버헤드전이는 Sequence Switching Code (SSC) 알고리즘의 확장성을 제한하는 가장 큰 걸림돌이 되어왔다. 본 논문에서는 보조선을 사용하지 않고 SSC 회로를 구현하는 방법과 함께 이 방법을 사용하여 보조선을 사용하였을 때 보다 오버헤드전이를 적게 발생시키는 방법을 제시하였다. 실험결과 새로운 방법을 적용함으로써 보조선을 사용하는 방식에 비하여 오버헤드전이의 발생을 50% 이하로 줄이고 알고리즘의 효율을 약 30% 향상시킬 수 있었다. The transition of auxiliary lines for transmitting coding information has been one of the major obstacles to restricting the scalability of Sequence Switch Coding (SSC) algorithms. A new design of SSC which does not use auxiliary lines is presented in this paper. The new design makes overhead transitions far less than the previous designs that use auxiliary lines. By applying the new technique, more than 50% of overhead transitions have been reduced, leading to the increase of 30% of the overall efficiency of SSC algorithm.

Draft Genome Sequence of Pseudomonas sp. Strain G5, Isolated from a Traditional Indigo Fermentation Dye Vat

Park, Sunhwa,Lee, Ji-Hoon,Cho, Yong-Joon,Chun, Jongsik,Hur, Hor-Gil The Korean Society for Applied Biological Chemistr 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.3

In previous study, alkaliphilic and thermotolerant bacterium strain, Pseudomonas sp. strain G5, capable of reducing insoluble indigo was isolated from Korean traditional fermentation liquor. Here, we report the draft genome sequence and annotation of strain G5 to provide the genomic information involved in indigo reduction process.

Less Volatile Value-at-Risk Estimation Under a Semi-parametric Approach

David K. Wang,Shih-Feng Huang 한국증권학회 2023 Asia-Pacific Journal of Financial Studies Vol.52 No.3

In this study, we propose a two-step, less-volatile value-at-risk (LVaR) estimation using a generalized nearly isotonic regression (GNIR) model. In the proposed approach, a VaR sequence is first produced under the generalized autoregressive conditional heteroskedasticity (GARCH) framework. Then, the VaR sequence is adjusted by GNIR, and the generated estimate is denoted as LVaR. The results of an empirical investigation show that LVaR outperformed other VaR estimates under the classic equally weighted and exponentially weighted moving-average frameworks. Furthermore, we show not only that LVaR is less volatile, but also that it performed reasonably well in various backtests.

Draft Genome Sequence of Pseudomonas sp. Strain G5, Isolated from a Traditional Indigo Fermentation Dye Vat

박선화,허호길,이지훈,조용준,천종식 한국응용생명화학회 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.3

In previous study, alkaliphilic and thermotolerant bacterium strain, Pseudomonas sp. strain G5, capable of reducing insoluble indigo was isolated from Korean traditional fermentation liquor. Here, we report the draft genome sequence and annotation of strain G5 to provide the genomic information involved in indigo reduction process.