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Malicious Processor Detection based on the Security Agent
Seong-Muk Choi,Yeol-Joo Ryou,Hoo-Ki Lee,Hee-Hoon Cho,Jong-Bae Kim 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.11
Recently, as Internet is widely used due to the increased spread of the internet network, the software with malicious intent is distributed via the internet and its infection path gets various too. In particular, attacks by Bot mainly work at C&C (command-and-control) server but it can be secured just by blocking IP because C&C server runs in form of IP. However, this attacker too gets gradually intelligent as they try to connect periphrastically in order to avoid server blocking. Once these malicious codes infiltrate user’s system, it is not easy to detect it through general detection method while it is running. In this paper, we propose malicious process detection system based on security agent in order to prevent damage caused by malicious code infection from spreading.
A Study of Effective Defense-In-Depth Strategy of Cyber Security on ICS
Seong-Muk Choi,Rae-Hyung Kim,Ga-Ye Kim,Hyeon-Kyung Lee,GwangYong Gim,Jong-Bae Kim 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.5
The system of SCADA(Supervisory Control and Data Acquisition Security) used in electricity, water, petroleum and gas, transportation as well as manufacturing, is to collect scattered data and to monitor assets related as a centralized suppression system. ICS system, including current SCADA, is not isolated from outside, being connected with IT solution, and can operate equipment through broadband network, instead of accessing physically. Accordingly, the security accident of suppressing system can occur in the fields of antagonistic nations, terrorists, foundational facility invaders, natural disasters and ill-will or accidental actions. The security control examined in this study provides a defense-in-depth strategy which is applicable to the effective cyber security strategy regarding ICS to protect the confidentiality of information, zero defect, availability through the classification of control, operational control and technological control.
A Study on the Malicious Process Detection System Model based on Security Agent
Seong-Muk Choi,Yeol-Joo Ryou,Hoo-Ki Lee,Hee-Hoon Cho,Jong-Bae Kim 한국정보통신학회 2015 2016 INTERNATIONAL CONFERENCE Vol.7 No.1
As recently use of Internet gets increased rapidly, infection path through the network becomes diverse. In particular, attacks by Bot mainly work at C&C (command-andcontrol) server but it can be secured just by blocking IP because C&C server runs in form of IP. However, these attackers too get gradually intelligent as they try to connect periphrastically in order to avoid server blocking. Once these malicious codes infiltrate user’s system, it is not easy to detect it through general detection method while it is running. In this paper, so, we propose malicious process detection system based on security agent in order to prevent damage caused by malicious code infection from being spread.
Experimental investigation of optical thyristor operating as optical hard-limiter
Kang, Tae-Gu,Choi, Dong-Muk,Choi, Woon-Kyung,Choi, Young-Wan,Kim, Seong-Joo,Choi, Woo-Kyung Wiley Subscription Services, Inc., A Wiley Company 2007 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.49 No.11
<P>We demonstrate the optical thyristor operating as optical hard-limiter (OHL) in the optical channel and AND gate logic element (AGLE). The oxidized PnpN vertical-cavity laser (VCL)–depleted optical thyristor (DOT) clearly shows the nonlinear s-shaped current-voltage and lasing characteristics. A switching voltage of 5.24 V, a holding voltage of 1.50 V, and a threshold current of 0.65 mA is measured, making these devices attractive for optical processing applications. The VCL–DOT operating as OHL would enhance the system performance because it would exclude some combinations of interference patterns from causing errors as in all previous works. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2779–2780, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22850</P>
Seong Woo Kim,Hyun Muk Choi 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.1
To improve the physical and gas barrier properties of biodegradable poly(lactic acid) (PLA) film, two graphene nanosheets of highly functionalized graphene oxide (0.3 wt% to 0.7 wt%) and low-functionalized graphene oxide (0.5 wt%) were incorporated into PLA resin via solution blending method. Subsequently, we investigated the effects of material parameters such as loading level and degree of functionalization for the graphene nanosheets on the morphology and properties of the resultant nanocomposites. The highly functionalized graphene oxide (GO) caused more exfoliation and homogeneous dispersion in PLA matrix as well as more sustainable suspensions in THF, compared to low-functionalized graphene oxide (LFGO). When loaded with GO from 0.3 wt% to 0.7 wt%, the glass transition temperature, degree of crystallinity, tensile strength and modulus increased steadily. The GO gave rise to more pronounced effect in the thermal and mechanical reinforcement, relative to LFGO. In addition, the preparation of fairly transparent PLA-based nanocomposite film with noticeably improved barrier performance achieved only when incorporated with GO up to 0.7wt%. As a result, GO may be more compatible with hydrophilic PLA resin, compared to LFGO, resulting in more prominent enhancement of nanocomposites properties.
최상묵,정찬민,홍성범,서인석 大韓成形外科學會 1997 Archives of Plastic Surgery Vol.24 No.4
The serratus anterior muscle is a large muscle located on the lateral aspect of the thorax. After first transfer as a free flap by Takayanagi and Tsukie in 1982, it has recently been used for reconstruction of the soft tissue defect of head and neck lesions as well as extremity injuries. It also has been transferred in combination with latissimus dorsi muscle, rib bone, and skin in reconstructing extensive compound defects. Authors have treated with free serratus anterior muscle flap in 15 cases of skin and soft tissue defect from May 1994 to June 1996. The sites of reconstruction were lower extremities in 11 cases, face in 2 cases, forearm and pelvis in each 1 cases. The causes of defect were chronic osteomyelitis combined with soft tissue defect in 7 cases, hypertrophic scar contracture in 4 cases, tumor in 3 cases, and cavernous hemangioma in 1 case. We also have performed combination flaps of latissimus dorsi muscle in 2 cases and rib bone graft in 3 cases. All flaps were survived and no secondary morbidity of donor site was observed. The advantages of free serratus anterior muscle flap are 1) reliability with consistently long and large pedicle, 2) easy flap dissection, 3) combined transfer, 4) less donor site morbidity, and 5) less postoperative bulkiness. Accordingly, it was flap of choice for small no moderate sized soft tissue defects in various site reconstruction.
다결정 실리콘 태양전지의 표면 텍스쳐링 및 반사방지막의 영향
전성욱(Seong-Uk Jun),임경묵(Kyung-Muk Lim),최석환(Sock-Hwan Choi),홍영명(Yung-Myung Hong),조경목(Kyung-Mox Cho) 한국표면공학회 2007 한국표면공학회지 Vol.40 No.3
The effects of texturing and anti-reflection coating on the reflection properties of multi-crystalline silicon solar cell have been investigated. The chemical solutions of alkaline and acidic etching solutions were used for texturing at the surface of multi-crystalline Si wafer. Experiments were performed with various temperature and time conditions in order to determine the optimized etching condition. Alkaline etching solution was found inadequate to the texturing of multi-crystalline Si due to its high reflectance of about 25%. The reflectance of Si wafer texturing with acidic etching solution showed a very low reflectance about 10%, which was attributed to the formation of homogeneous. Also, deposition of ITO anti-reflection coating reduced the reflectance of multi-crystalline si etched with acidic solution(HF+HNO₃) to 2.6%.
장승일(Seong-Il Jang),최선묵(Sun-Muk Choi),김대희(Dae-Hui Kim),오후규(Hoo-kyu Oh) 한국마린엔지니어링학회 2005 한국마린엔지니어링학회 학술대회 논문집 Vol.2005 No.-
The experiments were conducted without oil in a closed refrigerant loop which was driven by a magnetic gear pump. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and evaporator(test section). The test section was made of a horizontal stainless steel tube with the inner diameter of 4.57 ㎜, and length of 4 m. The experiments were conducted at mass flux of 200 to 700 ㎏/㎡s, saturation temperature of 0℃ to 20℃, and heat flux of 10 to 30 ㎾/㎡. The test results showed the evaporation heat transfer of CO₂ has great effect on more nucleate boiling than convective boiling. The evaporation heat transfer coefficients of CO₂ are highly dependent on the vapor quality, heat flux and saturation temperature. In comparison with test results and existing correlations, correlations failed to predict the evaporation heat transfer coefficient of CO₂, therefore, it is necessary to develop reliable and accurate predictions determining the evaporation heat transfer coefficient of CO₂ in a horizontal tube.
나승호(Seong-Ho Na),전재현(Jae-Hyun Jeon),최중묵(Jung-Muk Choi),안성국(Sung-Guk Ahn),김종백(Jong-Beck Kim) 전력전자학회 2011 전력전자학술대회 논문집 Vol.2011 No.7
일반적으로 인버터는 입력 전원에 정전이 발생하였을 때 수 ms 안에 PWM 출력을 차단한다. 부하의 관성이 큰 경우 전원이 복구되었을 때 부하를 가속하는데 긴시간이 필요하게 된다. 이러한 동작은 산업 현장에서 큰 손실로 이어질 수 있고, 따라서 출력을 차단하지 않고 연속운전 할 수 있는 Ride Through 모드를 자사 고압 인버터에 적용하였으며 실제 공정상의 실험으로 이를 검증 하였다.