• The Transactions of the Korea Information Processing Society
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• v.5 no.6
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• pp.1593-1602
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• 1998

In this paper, a hybrid firewall system using the screening router, dual-homed gateway, screened host galeway and the application level gateway is proposed, The screened host gateway is comjXlsed of screening router, DMZ and bastion host. All external input traffics are filtered by screening router with network protrcol filtering, and transmitted to the bastion host performing application level filtering, The dual homed gateway is an internlediate equipment prohibiting direct access from external users, The application level gateway is an equipment enabling transmission using only the proxy server. External users can access only through the public servers in the DMZ, but internal users can aeee through any servers, The rule base which allows Telnet only lo the adrnilllslratol is applied to manage hosts in the DMZ According to the equipmental results, denial of access was in orderof Web. Mail FTP, and Telnet. Access to another servers except for server in DMZ were denied, Prolocol c1mials of UDP was more than that of TCP, because the many hosts broadcasted to networds using BOOTP and NETBIOS, Also, the illegal Telnet and FTP that transfer to inside network were very few.

• Journal of the Korean Wood Science and Technology
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• v.25 no.2
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• pp.88-99
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• 1997

뉴질랜드산(産) 라디아타소나무의 수간(樹幹) 및 지재(枝材)에 발달(發達)되어 있는 압축이상재(壓縮異常材), 대응재(對應材) 및 측면재(側面材)의 해부학적(解剖學的) 특성(特性)을 광학현미경(光學顯微鏡), 주사전자현미경(走射電子顯微鏡) 그리고 투과전자현미경(透過電子顯微鏡)을 이용하여 조직학적(組織學的) 및 구성요소(構成要素)의 수량적(數量的) 측면(側面)에서 비교(比較), 검토(檢討) 하였다. 조직학적(組織學的)인 면(面)에서 볼 때 춘재(春材)로부터 추재(秋材)로의 가도관(假導管) 이행(移行)은 대응재(對應材)나 측면재(側面材)보다 압축이상재(壓縮異常材)가 훨씬 더 점진적(漸進的)이었다. 편심생장(偏心生長)으로 인해 연륜폭(年輪幅)은 압축이상재(壓縮異常材)가 가장 컸고 그 다음이 측면재(側面材) 및 대응재(對應材)의 순이었으며 추재솔(秋材率) 역시 압축이상재(壓縮異常材)가 대응재(對應材) 및 측면재(側面材)보다 컸다. 횡단면상(橫斷面上) 가도관(假導管) 형상면(形狀面)에서 압축이상재(壓縮異常材)가 원형(圓形)을 나타내는 반면 대응재(對應材)와 측면재(側面材)는 각형(角形)을 띠고 있었다. 또한 압축이상재(壓縮異常材)에서만 가도관(假導管)의 세포벽(細胞壁)에 나선강(螺旋腔)과 나선열(螺旋裂) (helical cavity and check), 슬릿(slit)형(形) 벽공구(壁孔口)가 존재(存在)하였으나 $S_3$층(層)이 결여(缺如)되어 있었으며 굴곡(屈曲)된 선단(先端)과 불규칙(不規則)한 형상(形狀)의 가도관(假導管) 및 세포간극(細胞間隙)이 자주 관찰(觀察)되었다. 직교분야(直交分野) 벽공(壁孔)은 압축이상재(壓縮異常材)가 가문비나무형(型) 그리고 대응재(對應材) 및 측면재(側面材)는 소나무형(型) 벽공(壁孔)을 나타냈다. 수량적(數量的) 특성(特性) 면에서 볼 때 가도관(假導管)의 길이는 압축이상재(壓縮異常材)가 가장 짧고 측면재(側面材)가 가장 길었으며 가도관(假導管)의 벽(壁) 두께는 압축이상재(壓縮異常材)가 대응재(對應材)나 측면재(側面材)보다 두꺼웠다. 수직수지구(垂直樹脂溝)는 대응재(對應材)가 그리고 수평수지구(水平樹脂溝)(방추형(紡錐形) 방사조직(放射祖織))는 압축이상재(壓縮異常材)의 쪽이 많았다. 결론적(結論的)으로 보면 라디아타소나무의 압축이상재(壓縮異常材)는 근본적으로 대응재(對應材)나 측면재(側面材)와는 상이(相異)한 특성(特性)을 지녔으나 대응재(對應材)와 측면재(側面材)는 거의 유사(類似)한 특성(特性)을 공유(共有)하는 것으로 밝혀졌다.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.8
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• pp.132-139
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• 2015

Visual SLAM(Simultaneous Localization And Mapping) has been used widely to estimate a mobile robot's location. Visual SLAM estimates relative motions with static visual features over image sequence. Because visual SLAM methods assume generally static features in the environment, we cannot obtain precise results in dynamic situation including many moving objects: cars and human beings. This paper presents a stereo vision based SLAM method in dynamic environment. First, we extract disparity map with stereo vision and compute optical flow. We then compute disparity change that is the estimated flow field between stereo views. After examining the disparity change value, we detect ROIs(Region Of Interest) in disparity space to determine dynamic scene objects. In indoor environment, many structural planes like walls may be determined as false dynamic elements. To solve this problem, we segment the scene into planar structure. More specifically, disparity values by the stereo vision are projected to X-Z plane and we employ Hough transform to determine planes. In final step, we remove ROIs nearby the walls and discriminate static scene elements in indoor environment. The experimental results show that the proposed method can obtain stable performance in dynamic environment.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.4
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• pp.177-183
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• 2016

Sewage treatment using microorganisms is affected by multiple factors such as microbial properties, characteristics of sewage and operating conditions, and nanoparticles inflow may cause negative effects on sewage treatment system especially on the system stability and efficiency. It was studied to assess the toxic effects of nanoparticles on microorganism growth. The activated sludge in the sewage treatment plant of university was cultured in the optimized medium for each strain. Bacillus (gram-positive), Pseudomonas and E.coli (gram-negative) in the activated sludge were selected as target microorganisms, and ZnO and $TiO_2$ were chosen as nanoparticles. For same concentration of nanoparticles, average growth inhibition rate of Bacillus was 60% or more, while that of Pseudomonas was less than 10%. The toxicity of nanoparticles was shown to be higher for gram-positive bacteria than gram-negative bacteria because of their differences on structure of cell wall, components of cell wall protein, physiology of cells and metabolism. ZnO affected 3 times more negative on the growth of microorganisms as compared to $TiO_2$. It was assumed that, therefore, toxicity of ZnO was found to be greater than $TiO_2$.

• Applied Chemistry for Engineering
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• v.25 no.2
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• pp.174-180
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• 2014

A plasma hydrophobic coating on commercial fish feed was conducted to prolong the floating time of feed, thereby enhancing the feed consumption rate and reducing the contamination of water in fish farms. The hydrophobic coating on the fish feed was prepared using an atmospheric-pressure dielectric barrier discharge (DBD) plasma with hexamethyldisiloxane (HMDSO), toluene and n-hexane as the precursors. The effect of the parameters such as input power, precursor type and coating time on the coating performance were examined. The physicochemical properties of the coating layer were analyzed using a Fourier transform infrared (FTIR) spectrometer and a contact angle (CA) analyzer. The water CA increased after the coating preparation, indicating that the surface changed from hydrophilic to hydrophobic. The FTIR characterization revealed that the hydrophobic layer was comprised of functional groups such as $CH_3$, Si-O-Si and Si-C. As a result of the hydrophobic coating, the floating time of the fish feed increased from several seconds to 3 minutes, which suggested that the plasma coating method could be a viable means for practical applications. Compared to the water CA measured as soon as the coating layer was prepared, the 6-day aged sample exhibited a substantial CA increase, confirming the aging effect on the improvement of the hydrophobicity.

• Journal of Life Science
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• v.16 no.5
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• pp.834-839
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• 2006

This study was carried out to investigate changes in cell wall components and solubilization and depolymerization of pectin and neutral sugar polymers during softening of 'Tsugaru' apples. Pectic polysaccharides were solubilized in different solvents, distilled-water, 0.05 M CDTA, 0.05 M $Na_2CO_3$, and 8 M KOH, from cell wall materials during fruit softening. The uronic acid contents in distilled-water fraction rapidly increased along with fruit softening at 4 weeks after ambient storage. In the change of non-cellulosic neutral sugars in the cell wall of ‘Tsugaru’ fruits, the major sugar was galactose and arabinose in distilled-water, 0.05 M CDTA and 0.05 M $Na_2CO_3$ soluble fractions, and it was glucose, galactose and xylose in 8 M KOH fraction. Especially the change of galactose contents in distilled-water fraction was increased greatly along with fruit softening. When uronic acid polymers (UAP) and carbohydrate polymers (CP) in distilled-water fraction were filtered and separated using Sepharose CL-2B column, the high molecular UAP and CP were degraded to the low molecular ones from at harvest to softening fruit. Thus, the amount of high molecular polymers were greatly decreased along with fruit softening.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.595-599
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• 2009

Sarcocystis grueneri-like sarcocysts were found from the cardiac muscles of a rearing red deer (Cervus elaphus) carcass in Korea. In the light microscopical examination of sarcocysts, they were oval to spherical cysts and 90-170$\times$110-380 ${\mu}m$ in size. However, there was no inflammation and myofiber degeneration. In the transmission electron microscope, these cysts were located within the sarcoplasm of the host cell and filled with merozoites. The sarcocysts were enclosed by a very thin wall (0.45-0.6 ${\mu}m$ thick) that consists of protrusions and ground substance. The primary cyst wall formed numerous strip-like protrusions which were 0.2-0.3 ${\mu}m$ wide and up to 4.2 ${\mu}m$ long. The protrusions were running in parallel with the surface of the cyst. A characteristic of the cyst wall was absent of fibrils inside the protrusions. Merozoites in the compartment measured about $15\times4\;{\mu}m$. The merozoite consisted of four regions: micronemes and rhoptries, amylopectin granule, nucleus, and amylopectin granules. The number of rhoptry was counted in 7-13.

• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.128-134
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• 2007

Previously, we isolated plant growth promoting rhizobacterium (PGPR) Bacillus licheniformis K11 which could produce auxin, cellulase and siderophore. The siderophore of B. licheniformis K11 $(siderophore_{K11})$ was determined to be a catechol type siderophore which is produced generally by Bacillus spp. B. licheniformis K11 could produce the siderophore most highly after 96 h of incubation under nutrient broth at $20^{\circ}C$ with initial pH 9.0. For the production of the $siderophore_{K11}$, trehalose and $NH_4Cl$ were the best carbon and nitrogen sources in Davis minimal medium, respectively. The $siderophore_{K11}$ was Produced in M9 medium (pH 9.0) after 4 days at $20^{\circ}C$, and purified from culture broth of B. licheniformis K11 by using Amberlite XAD-2, Sephadex LH-20 column chromatography, and reversed-phase HPLC. The $siderophore_{K11}$ had the biocontrol activity against spore germination of P. capsici and F. oxysporum on potato dextrose agar (PDA). The results indicate that the $siderophore_{K11}$ is an antifungal mechanism of B. licheniformis K11 against phytopathogenic fungi.

• Journal of Korea Water Resources Association
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• v.40 no.2 s.175
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• pp.183-190
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• 2007

Soil layer in vegetation filter strip is one of the very important factor for reduction of non-point pollutants by physical, chemical and biological reactions of it through infiltration process. This study was carried out to prepare more effective vegetation filter strip through modification of soil layer for river water quality improvement. Therefore, the main aims of this study are to compare and evaluate normal (straighten type) and modified (step type) vegetation filter strip, which make artificially change the soil layer to improve infiltration ability, through bench scale experiments. In the results of this study, vegetation filter strip of step type is much more highly reduction effectiveness of pollutants in surface flow compared with normal vegetation filter strip. In case of below effluent, however, it appeared that the vegetation filter strip modified soil layer showed lower reduction effectiveness of pollutants than the general vegetation filter strip. This result was judged because effluent through the vegetation filter strip of step type passed bigger size of aggregate or sand than the vegetation filter strip of straighten type. If we compare it as a definition of pollutant load to estimate total amount of reduced pollutants by vegetation filter strip, reduced pollutants load by step type showed higher than those by straighten type because below effluent amount relied on total effluent amount was higher at step type (4%) than at straighten type (2%). In conclusion, the vegetation filter strip of step type to improve infiltration effect is much more reduction effectiveness of pollutants than vegetation filter strip of straighten type.

• Korean Journal of Microbiology
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• v.41 no.4
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• pp.255-261
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• 2005

A 6.7kb DNA fragment containing the sprT gene encoding Streptomyces griseus trypsin (SGT) was cloned from Streptomyces griseus ATCC 10137, and the complete nucleotide sequence was determined. Nucleotide sequence and deduced amino acid or the EcoRI-HindIII fragment revealed the presence or the six complete ORFs containing the sprT gene and one incomplete ORF, which were named ORF1, SGT, ORF2, ORF3, ORF4, ORF5, and ORF6, respectively. ORF1 has homology with the oxidoreductases from several organisms. ORF2 and ORF3 show similarity with unknown proteins and transcription regulator that belongs to the ArsR family, respectively. ORF4 and ORF5 show homology with the peptidoglycan bound protein with LPXTG motif from Listeria monocytogenes and the membrane protein with transmembrane helix from several organisms, respectively. The last ORF, ORF6, shows homology with the lipoprotein from Streptomyces avermitilis.