• Review of KIISC
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• v.16 no.5
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• pp.65-71
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• 2006

사이버 공격이 급증함에 따라 이를 사전에 효과적으로 예방할 수 있는 소프트웨어 보안 테스팅의 필요성이 점차 증대되고 있다. 결함 주입 기법은 사이버 공격과 마찬가지로 프로그램의 외부에 노출된 인터페이스에 고의적으로 결함을 주입하는 방법으로 보안 취약점을 찾는 우수한 방법이다. 이 논문에서는 결함 주입 기법의 기본적인 개념을 살펴본다. 또한, 결함 주입을 수행하는 절차인 결함 주입 대상 외부 인터페이스 선택, 결함 유발 가능 입력 데이터 생성, 결함 주입에 따른 이상현상 탐지 각각에 대한 개요 및 최근 동향을 기술한다.

• Korean Journal of Optics and Photonics
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• v.11 no.4
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• pp.265-270
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• 2000

We investigate the effects of the power and wavelength of externally injection seeded light on timing jitter and pulse width in a gain-switched $1.55\mu\textrm{m}$ DFB semiconductor laser by numerical simulation based on the transmission line laser model. As external seeding power increases, the timing jitter decreases and the pulse width increases. The lowest timing jitter is observed when the seed wavelength is aligned with the chirped spectrum center. By external seeding, we can decrease the timing jitter up to 1/2.7 without noticeable increase in pulse width. Our simulation results reasonably well agree with our sampled experiment and the other published papers. This proves the validity of our model to analyze a system based on a semiconductor laser. laser.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.1
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• pp.84-93
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• 2004

This study was performed : 1) to find the suitable HRT(hydralic retention time), 2) to evaluate the effects of the ratio of mixing/aeration time and injection time of external carbon source, for the removal of organics, nitrogen and phosphorus in swine wastewater by SBR(sequencing batch reactor process), which is one of the biological treatment process. The result of this study were summarized as follows : (1) As the ratio of mixing/aeration time was higher, $NH_4{^+}-N$ removal efficiency was increased and it was increased with increasing injection time of external carbon source because nitrification was affected by denitrification microbes propagation when injection time of external carbon soruce was shorted. T-N removal efficiency was increased with increasing the ratio of mixing/aeration time and injection time of external carbon source. (2) The T-P removal efficiency showed a great difference in each operating condition, and it was increased with increasing the ratio of mixing/aeration time increased and when the injection time of external carbon source was shorted because denitrification was done with effect by denitrification microbes propagation. (3) The highest removal efficiency of organic and nitrogen were obtained by the operating condition of Run 4-1(the ratio of mixing/aeration time : 16.5/5.5, injection time of external carbon source : 15hours) and T-P were obtained by the operation condition of Run 4-2(the ratio of mixing/aeration time : 16.5/5.5, injection time of external carbon source : 3hours), and efficiency(effluent concentration)of $BOD_5$, $COD_{Mn}$, $COD_{Cr}$, T-N and T-P in the treated water was 96.1%, 87.7%, 90.6%, 86.6% and 84.5%, respectively.

• Korean Journal of Plant Tissue Culture
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• v.21 no.6
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• pp.363-367
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• 1994

In an effort to investigate the role of calmodulin (CaM) as a modulating molecule in the signal transduction system in plant cells, we established methods for introduction of purified CaM into cultured soybean cells. CaM was purified from bovine testis, and was labelled with fluorescein isothiocyanate (FITC). Suspension -cultured cells were healed with saponin (0.1 mg/mL) to permeabilize the plasma membrane and coincubated with FITC-CaM complex. Saponin pretreatment was found to increase the fluorescence in the suspension cultured cells, indicating that the FITC-CaM complex could be incorporated into the cytoplasm. Optimal conditions for introducing FITC-CaM complex into protoplasts by electroporation were established with various electric pulses. With increasing field strength, the fluorescence in the protoplase was increased, while the viability of the protoplase decreased. FITC-CaM complex was successfully introduced into the protoplasts by electroporation and the amount of FITC-CaM complex in the protoplase was estimated.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.6
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• pp.687-692
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• 2006

This experiment was performed to evaluate the characteristics of BNR system performance, behavior of pollutants as organic and nitrogen at each basin and the effects of C/N ratio on biological nitrogen removal with methanol as an external carbon source for a low C/N ratio municipal wastewater. A lab-scale $A_2O$ system by employing the aerobic basin with the fluidized polyurethane media, which was $10{\sim}20$ mm rube type like a sponge, was used. The aerobic basin was hybrid type to be suspended and fixed biomass. The obtained results from this study were as follows; When no methanol was added, suspended biomass was 3 times more than that of the fluidized media in this system(total biomass 80 g). Biomass growed by an external carbon was firstly attached on media, and then suspended. $COD_{Cr}$ concentration for the effluent was a range of 13 to 29 mg/L regardless of pouring an external carbon. For nitrogen, the effluent concentration was $20.0{\sim}35.9mg/L$(removal efficiency; 18%) in case of no addition of an external carbon, but was $2.5{\sim}9.0mg/L$(removal efficiency ; $71{\sim}83%$) with addition of methanol. For the characteristics of pollutants removal, most of $COD_{Cr}$ were removed at the anaerobic basin when no external organic carbon was added, and were removed at the anoxic basin in case of adding external organic carbon but at the aerobic basin in case of adding excess external organic carbon. On the other hand, most TIN(total inorganic nitrogen) were removed at the anaerobic basin when no external organic carbon was added, but when an external organic carbon was added, they were removed at the anaerobic basin under unstable condition and at the anoxic basin under stable condition.

• The Korean Journal of Zoology
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• v.33 no.3
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• pp.365-372
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• 1990

For the effort to produce transgenic amphibians, a plasmid DNA sequence (cytoplasmic actin promoter-linked bacterial $\beta$-galactosidase gene) was microinjected into fertilized Xenopus eggs. It appeared that the injection of 20 nl solution containing 1-2 ng of DNA was not toxic, but over 4 ng was toxic to embryonic development. The translational product of $\beta$-gal gene ($\beta$-galactosidase) had enzyme activity in all three germ layers of the embryo. Expression of the injected $\beta$-gal genes was first detected at mid-gastrula stage, and the activity persisted up to stage 43 (feeding tadpole) with decreased level of retention. However, the level of the expression was various among the injected individuals as well as each experiment. That is, $\beta$-galactosidase activities did not appear in all cells, instead a localized distribution pattern. Although other possibilities could not be omitted, this mosaic distribution of gene expression seemed to arise from unequal partition of the injected DNA into each blastomere during early cleavage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.57-64
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• 2017

Today, due to the environmental regulations regarding air pollution in the EU, the use of EPS (Styrofoam) as the cushioning material in the packaging industry is decreasing. In effect, air cushioning based cushioning materials are rapidly expanding into the market and replacing EPS, due to their excellent buffering ability and environmental friendliness. This is a new selective filling type air filling material manufacturing technology that affords improvements in the amount of raw materials required, its processing and its aesthetic appearance compared to the conventional air filling cushioning materials. In this study, a multi-stage air cell filling valve molding technology is developed based on selective filling technology, which allows packages to be selectively filled in various forms by applying valve forming structure technology. This multi-stage air cell filling valve molding technology is a technique in which a plurality of injection ports are formed by laminating three layers of films, viz. a first injection film, a valve film, and a second injection film having valve ends. In the conventional technology, a separate external air injection path for injecting air into a plurality of connected air bags is needed. However, in the proposed system, an external air injection path is formed inside the air bag, Due to the lack of need for an injection furnace, the raw material and process are reduced and air is injected and then discharged, while the air bag is reduced in length to 63 ~ 66% of its normal value. The outer surface of the outer air injection path is integrated inside by maintaining the original length of the cross section, while the unnecessary folded air is injected into the interior of the air bag, This smart air filling type cushioning material manufacturing technology constitutes a big improvement over the existing technologies.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.304-309
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• 1996

차세대원자로(KNGR) 안전주입계통은 원자로용기 하향유로(RVDC)로 직접주입(DVI)되도록 설계되며 이는 4-트레인 안전주입계통의 설계에 있어 고유한 기본구조이다. DIV 채택으로 인해 가압열충격(PTS)과 관련된 인허가 상의 관심사론 조사하고 DVI 주입구 위치에 대한 RVDC에서의 유체거동과 온도분포를 상용전산코드인 FLOW3D를 이용하여 분석하였다. PTS관점에서 가장 최악의 경우인 외부 전원상실을 동반한 영출력 주증기관 파단사고를 해석대상으로 하였으며 사고후 570 ~ 600초 사이의 과도상태를 분석하였다. 본 연구의 결과로 주증기관 파단으로 야기되는 자연순환에 의한 열혼합은 충분히 이루어져 RVDC에서의 온도가 R $T_{PTS}$ 이상임을 확인했고 손상루프측 위의 DVI 주입구의 유동중 일부가 손상루프측 저온관 유동과 상호작용하여 건전루프측 저온관아래로 흐르며 이 영향으로 건전루프측 저온관 아래에서의 온도가 국부적으로 감소함을 확인하였다.다.

• Review of KIISC
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• v.31 no.1
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• pp.15-23
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• 2021

자율주행 시스템이 탑재되어 있는 무인이동체는 운용환경에 따라 공중, 해상, 육상 무인이동체로 분류할 수 있고 모든 분야에서 관련 기술 개발이 활발히 진행되고 있다. 무인이동체는 자율주행 시스템이 탑재되어 외부 환경을 스스로 인식해 상황을 판단하는 특징을 갖고 있다. 따라서, 무인이동체는 센서로부터 수집되는 데이터를 이용하여 주변 환경을 인식해야 한다. 이러한 이유로 보안 (Security) 분야에서는 무인이동체에 탑재되는 센서를 대상으로 신호 오류주입을 수행하여 해당 무인이동체의 오동작을 유발하는 연구결과들이 최근 발표되고 있다. 신호 오류주입공격은 물리레벨 (PHY-level) 에서 수행되기 때문에, 공격 수행 여부를 소프트웨어 레벨에서 탐지하는 것은 매우 어렵다는 특징을 갖고 있다. 현재까지 신호 오류주입 공격을 탐지할 수 있는 방법은 다수의 센서를 이용하는 센서퓨전 (Sensor Fusion)을 기반으로 하는 방법이 있다. 하지만, 현실적으로 하나의 무인이동체에 동일한 기능을 하는 센서 여러 개를 중복해서 탑재하는 것은 어려움이 있다. 그리고 단일 센서만을 이용하여 신호 오류주입 공격을 탐지하는 방법에 대해서는 아직까지 연구가 진행되고 있지 않다. 본 논문에서는 무인이동체 환경에서 가장 널리 사용되고 있는 MEMS 센서를 대상으로 신호 오류주입 공격을 재연하고, 단일 센서 환경에서 해당 공격을 탐지할 수 있는 방법에 대하여 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1154-1157
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• 2010

최근 물리적인 보안이 큰 위협이 되는 가운데 물리적 공격 중에서도 오류 주입을 통한 공격이 국내에서도 본격적으로 연구가 시작되고 있다. 특히 중국인의 나머지 정리를 이용한 RSA-CRT 알고리즘은 오류 주입 공격을 통해서 비밀 값 p, q가 쉽게 추출 되어 취약하다는 것이 실험적으로 검증이 되었다. 본 논문에서는 레이저를 통한 광학적 오류 주입 공격을 시도 했으며 외부 버퍼를 이용해서 정확하게 원하는 시점에 오류를 주입함으로 레이저 장비 특성에 따른 오류 주입 값의 변화를 확인하였다.