• Korean Journal of Microbiology
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• v.43 no.2
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• pp.106-110
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• 2007

The detection and distribution of Aeromonas in water supplies were investigated by using the USEPA Method 1605. Water samples were collected from the Han River, finished waters and tap waters supplied from Water Treatment Plants in Seoul monthly from July 2002 to December 2003. Aeromonas species in each water sample were quantified based on the development of yellow colonies on the surface of membrane filter using a selective medium (Ampicillin-Dextrin Agar with Vancomycin). The Quality Control (QC) for this study met the acceptance criteria of Method 1605. The concentrations of Aeromonas species in surface water samples ranged from $1.0{\times}10^{0}\;to\;9.8{\times}10^{3}\;CFU/ml$. Aeromonas species were found only in one tap water sample with concentration of 1 CFU/500 ml. No Aeromonas species were found in any finished water samples. Aeromonas species detected here were identified as A. salmonicida(51%), A. caviae(4.7%), A. schubertti(3.4%), A. sobria(3.8%), A. hydrophila(2.1%), and A. ichithiosmia(0.4%). A. salmonicida was the dominant species, which is of no significance to human health. Chlorine resistance of A. salmonicida was evaluated and as a result, 99.99% of A. salmonicida decreased after 30 seconds exposure at residual free chlorine 0.2 mg/L. These suggest that the waters supplied in Seoul may be safe against the pathogenic agent Aeromonas.

• Korean Journal of Materials Research
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• v.10 no.7
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• pp.489-492
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• 2000

Three different white cast irons alloyed with Cr and Si were prepared in order to study their distribution be-havior in matrices and carbides. The specimens were produced using a 15kg-capacity high frequency induction fur-nace. Melts were super-heated to $1600^{\circ}C$, and poured at $1550^{\circ}C$ into a pepset mold. Three combinations of the alloys were selected so as to observe the distribution behavior of Cr and Si : 0.5%C-25.0%Cr-1.0%Si(alloy No. 1), 0.5%C-5.0%Cr-1.0%Si(alloy No. 2) and 2.0%C-5.0%Cr-1.0%Si(alloy No. 3). Cellular $M_7C_3$ carbides-$\delta$ferrite eutectic were developed at $\delta$ferrite liquid interfaces in the alloy No. 1 while only traces of $M_7C_3$ carbides-$\delta$ferrite eutectic were precipitated in the alloy No. 2. With the addition of 2.0% C and 5.0% Cr, ledeburitic $M_3C$ carbides instead of cellular $M_7C_3$ carbides were precipitated in the alloy No. 3. Cr was distributed preferentially to the $M_7C_3$ carbides rather than to the matrix structure while more Si was partitioned in the matrix structure rather than the $M_7C_3$ carbides. $K^m$ for Cr was ranged from 0.56 to 0.68 while that for Si was from 1.12 to 1.28. $K^m$ for Cr had a lower value with increased carbon contents. The mass percent of Cr was higher in the $M_7C_3$ carbides with increased Cr contents.

• The KIPS Transactions:PartA
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• v.8A no.3
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• pp.189-200
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• 2001

This paper proposes a memory allocation model for Real-Time Linux. The proposed model allows users to create several continuous memory regions in an application, to specify an appropriate region allocation policy for each memory region, and to request memory blocks from a necessary memory region. Instead of using single memory management module in order to support the proposed model, we adopt two-layered structure that is consisted of region allocators implementing allocation policies and a region manager controlling regions and region allocator modules. This structure separates allocation policy from allocation mechanism, thus allows system developers to implement same allocation policy using different algorithms in case of need. IN addition, it enables them to implement new allocation policy using different algorithms in case of need. In addition, it enables them to implement new allocation policy easily as long as they preserver predefined internal interfaces, to add the implemented policy into the system, and to remove unnecessary allocation policies from the system, Because the proposed model provides various allocation policies implemented previously, system builders can also reconfigure the system by just selecting most appropriate policies for a specific application without implementing these policies from scratch.

• KSBB Journal
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• v.11 no.1
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• pp.8-14
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• 1996

Bacillus subtillis strains with transition state regulator mutations and a spore mutation were developed for the overexpression of apsE and for the enhancement of expression level. Among the many regulator genes, degU and hpr were chosen as a representative positive and negative regulator for the aprE, respectively. Spo II G was used for the construction of asporogeneous strains. All the mutants were constructed from two protease-deleted strain DB104 and the apsE gene was transformed with an integration vector pMK101. DB104(deg$U^h$(32) $his^+$)::pMK101(Cm) and DB104($\Delta$her(Em))::pMKl01(Cm) show 7-fold and about 2-fold increase in aprE expression level, respectively. But the effect of transition state regulator mutation on the aprE expression was diminished when the integrated aprE gene was amplified by the high concentration of chloramphenicol, i. e. 30 $\mu\textrm{g}$/ml. DB104($\Delta$spoIIG(Pm) degUh(32) his+)::pMK101(Cm) and DB104($\Delta$spoIIG(Pm) $\Delta$hpr(Em))::pMK101 double mutant show 10-fold and 3-fold increase in aprE expression level, respectively. The results suggest that sporulation mutation and transition state regulator mutation have independent and additive effect on the aprE expression, and the same gene dosage effect on the transition state regulator mutation was also identified.

• Journal of Korean Society of Forest Science
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• v.83 no.4
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• pp.441-449
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• 1994

The two reflective channels(red and near infrared spectrum) of advanced very high resolution radiometer(AVHRR) data were used to classify primary vegetation cover types in the Korean Peninsula. From the NOAA-11 satellite data archive of 1991, 27 daytime scenes of relatively minimum cloud coverage were obtained. After the initial radiometric calibration, normalized difference vegetation index(NDVI) was calculated for each of the 27 data sets. Four or five daily NDVI data were then overlaid for each of the six months starting from February to November and the maximum value of NDVI was retained for every pixel location to make a monthly composite. The six bands of monthly NDVI composite were nearly cloud free and used for the computer classification of vegetation cover. Based on the temporal signatures of different vegetation cover types, which were generated by an unsupervised block clustering algorithm, every pixel was classified into one of the six cover type categories. The classification result was evaluated by both qualitative interpretation and quantitative comparison with existing forest statistics. Considering frequent data acquisition, low data cost and volume, and large area coverage, it is believed that AVHRR data are effective for vegetation cover type mapping at regional scale.

• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.543-549
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• 2000

Gutta-percha와 근관sealer를 사용한 근관 충전은 가장 많이 이용되고 성공률이 높은 방법이지만, 현재 사용되는 모든 근관sealer는 미세누출을 나타낸다. 따라서 더 효과적인 근관 폐쇄를 이루기 위한 재료 및 방법들이 연구되어왔다. 이중 상아질 접착제는 근관 충전재와 함께 사용되어 미세누출을 감소시키지만, 근관 내에 사용하기에 술식이 복잡하고 기술이 요구된다. 본 연구의 목적은 gutta-percha와 레진계 근관 sealer로 충전한 근관에서 self-etching primer를 미리 도포한 경우와 도포하지 않은 경우의 치근단 미세누출을 비교하고, self-etching primer를 도포함에 있어 근관 내에 적용하는 방법에 따른 미세누출을 비교하는 것이다. 또한 근관sealer와 상아질 계면을 주사전자현미경으로 관찰하여, 이 결과를 미세누출과 관련시켜보고자 하였다. 36개의 발거된 사람의 단근치에서 치관부를 절단, 제거하고 ProFile로 근관 형성한 후, 무작위로 선택하여 4개의 군으로 분류하였다. 1군에서는 주사기와 30게이지 주사 바늘로 self-etching primer를 근관 내에 적용하였고, 2군에서는 self-etching primer를 paper point에 적셔 근관 내에 적용하였다. 3군에서는 self-etching primer를 적용하지 않았다. 1, 2, 3군의 치아를 gutta-percha와 AH26 sealer를 사용하여 continuous wave 충전법으로 충전한 후 치근단공 주위 3mm를 제외한 치근변에 nail polish를 2회 도포하였고, 4군(음성 대조군)은 치근면 전체에 도포하였다. 1군과 2군에서 각각 2개의 치아는 주사전자현미경적 관찰을 위해 준비하였다. 모든 치아를 Methylene Blue 수용액에 48시간동안 침적, 수세한 후 치아 장축에 평행하게 양분하여 10배의 실물확대현미경 하에서 치근단 색소 침투를 관찰하였다. Self-etching primer를 도포한 군과 도포하지 않은 군 사이에는 평균 미세누출량에 유의한 차이가 없었다. 주사 바늘로 적용한 군과 paper point로 적용한 군 사이에도 평균 미세누출량에 유의한 차이가 없었다. 상아질과 근관 sealer계면의 주사전자현미경 관찰 결과 일부분에서 긴밀한 접착 관계를 나타내었고, 다른 부분에서는 간극을 나타내었다.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.1
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• pp.72-79
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• 2009

This paper describes the performance evaluation of NHD(nonhomogeneity detector) for STAP(space-time adaptive processing) airborne radar according to various normalization methods in the nonhomogeneous clutter environment. In practice, the clutter can be characterized as random variation signals, because it sometimes includes signals with very large magnitude like impulsive signal due to the system environment. The received interference signals are composed of homogeneous and nonhomogeneous data. In this situation, NHB is needed to maintain the STAP performance. The normalization using the NHD result is an effective method for removing the nonhomogeneous data. The optimum normalization can be performed by a representative value considered with a characteristic of the given data, so we propose the K-means clustering algorithm. The characteristic of random variation data due to nonhomogeneous clutters can be considered by the number of clusters, and then the representative value for selecting the homogeneous data is determined in the clustering result. In order to reflect a characteristic of the nonstationary interference data, we also investigate the algorithm for a calculation of the proper number of clusters. Through our simulations, we verified that the K-means clustering algorithm has very superior normalization and target detection performances compared with the previous introduced normalization methods.

• Microbiology and Biotechnology Letters
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• v.34 no.3
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• pp.185-195
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• 2006

Phytoremediation is an economical and environmentally friendly bioremediation technique using plants which can increase the microbial population in soil. Unlike other pollutants such as heavy metals, poly-chlorinated biphenyl, trichloroethylene, perchloroethylene and so on, petroleum hydrocarbons are relatively easily degradable by soil microbes. For successful phytoremediation of soil contaminated with petroleum hydrocarbons, it is important to select plants with high removal efficiency through microbial degradation. In this study, we clarified the roles of plants and rhizobacteria and identified their species effective on phytore-mediation by reviewing the papers previously reported. Plants and rhizobacteria can degrade and remove the petroleum hydrocarbons directly and indirectly by stimulating each other's degradation activity. The preferred plant species are alfalfa, ryegrass, tall fescue, poplar, corn, etc. The microorganisms with a potential to degrade hydrocarbons mostly belong to Pseudomonas spp., Bacillus spp., and Alcaligenes spp. It has been reported that the elimination efficiency of hydrocarbons by soil microorganisms can be improved when plants were simultaneously applied. For more efficient restoration, it's necessary to understand the plant-rhizobacteria interaction and to select the suitable plant and microorganism species.

• Cartoon and Animation Studies
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• s.49
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• pp.651-676
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• 2017

Shadow images are a representative medium and means of expression for the imagination that exists between consciousness and unconsciousness for thousands of years. Wherever light exists, people create play with their own shadows without special skills, and have made a fantasy at once. Shadow images have long been used as subjects and materials of literacy, art, philosophy, and popular culture. Especially in the field of art, people have been experimenting with visual stimulation through the uniqueness of simple silhouettes images. In the field of animation, it became to be recognized as a form of non - mainstream areas that are difficult to make. However, shadow images have been used more actively in the field of digital arts and media art. In this Environment with technologies, Various formative imaginations are being expressed more with shadow images in a new dimension. This study is to introduce and analyze these trends, the aesthetic transformations and extended methods focusing on digital silhouette animation and recent media art works using shadow images. Screen-based silhouette animation combines digital technology and new approaches that have escaped conventional methods have removed most of the elements that have been considered limitations, and these factors have become a matter of choice for the directors. Especially, in the display environment using various light sources, projection, and camera technology, shadow images were expressed with multiple-layered virtual spaces, and it becomes possible to imagine a new extended imagination. Through the computer vision, it became possible to find new gaze and spatial images and use it more flexibly. These changes have given new possibility to the use shadow images in a different way.

• Journal of Sensor Science and Technology
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• v.1 no.2
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• pp.183-194
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• 1992

Some silicon micromechanical structures useful in sensors and actuators have been fabricated by electropolishing or porous silicon formation technique by anodic reaction in HF solution. The microstructures were lightly doped single crystal silicon and the formation was isotropic independent of crystal directions. Porous silicon layer(PSL) was formed selectively in $n^{+}$ region of $n^{+}/n$ silicon structure by anodic reaction in concentrated HF(20-48%) solution. Characteristics of the formed PSL were investigated along with change of the reaction voltage, HF concentration and the reaction time. PSL was formed only in $n^{+}$ region. The porosity of the PSL was decreased with the increase of HF concentration and independent of reaction voltage. For the case of $n/n^{+}/n$ structures, the etched surface of silicon was fairly smooth and a cusp was not found. The thickness of the microstructures was the same as that of the epitaxial n-Si layer and good uniformity. We have fabricated acceleration sensors by anodic reaction in HF solution(5 wt%) and planar technology. The process was compatible with conventional It fabrication technique. Various micromechanical structures, such as rotors of motor, gears and linear actuator, were also fabricated by the technique and examined by SEM photographs.