• 한국통신학회논문지
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• 제16권11호
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• pp.1037-1053
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• 1991

본 논문에서는 근사 포화형 경로 절정 알고리즘을 제안한다. 이 방식의 주 Idea는 flooding 되어 망의 경계로 소멸해가는 search message들을 이용하여 각 노드의 path table을 갱신함으로써 각 노드가 이 정보를 가지고 자신에게 도착하는 search message들이 망의 congestion의 증가가 가장 작은 path를 선택하게 함으로써 망의 congestion을 control하는 것이다. 이 알고리즘의 유용함을 인지시키고자 회전 교환 망과 패킷 교환 망에서 각각 모의 실험을 하였다. 또한 제안된 알고리즘은 다른 분석적인 알고리즘들과 비교할 때 거의 비슷한 성능을 갖음을 알았다. 이 방식의 overhead는 망의 데이타 베이스 관리부에 부가하는 work load이다. 그러나 이 work load는 알고리즘이 제공하는 효율적인 congestion control로 인하여 충분히 상쇄할 수 있다. 이 알고리즘은 configuration이 자주 변하는 동작인 망에서 뿐만 아니라 일반 상용 망에서도 유용한 것이다.

• 디지털융복합연구
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• 제14권11호
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• pp.305-311
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• 2016

최근 자동차 업계는 무선 인터넷 기술의 발달과 응용의 확산으로 자율 주행의 연구가 활발히 진행 중에 있으나 교통사고는 아직도 해결되지 않는 부분이다. 사고의 요인으로는 졸음운전, 운전자의 실수, 환경적인 요소, 잘못된 도로 구조 등이 있으며 사고 원인의 하나인 운전자의 운전 행태와 특성은 교통사고에 큰 영향을 미친다. 본 논문에서는 자율 주행 및 자가 운전을 하는 경우에 발생 할 수 있는 교통사고에서 사고발생 전에 나타날 수 있는 사행운전의 특성을 판단하기 위한 연구를 수행하였다. 기존 연구에서는 영상기법이나 1,2차로의 운전행태로 횡방향 각속도 변화의 특성으로 사행 운전을 판단하였으나 본 논문은 센서의 값을 이용하여 횡방향의 이동거리와 임계 범위를 설정하여 사행 운전을 검출하는 연구를 진행하였다.

• Molecules and Cells
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• 제26권1호
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• pp.26-33
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• 2008

The plasmid pJB01, a member of the pMV158 family isolated from Enterococcus faecium JC1, contains three open reading frames, copA, repB, and repC. Plasmids included in this family produce counter-transcribed RNA (ctRNA) that contributes to copy number control. The pJB01 ctRNA, a transcript which consists of 54 nucleotides (nts), is encoded on the opposite strand from the copA/repB intergenic region and partially overlaps an atypical ribosome binding site (ARBS) for repB. The ARBS is integrated by the two underlined conserved regions: 5'-TTTTTGTNNNNTAANNNNNNNNNATG-3', and the ctRNA is complementary only to the 5' conserved sequence 5'-TTTTTGT-3'. This complementary sequence is located at a distance from the terminal loop of the ctRNA secondary structure. The ctRNA structure predicted by the mfold program suggests the possible generation of a terminal and an internal hairpin loop. The amount of in vitro translation product of repB mRNA was inversely proportional to the ctRNA concentration. Mutations in the terminal and internal hairpin loops of the ctRNA had inhibitory effects on its binding to the target mRNA. We propose that the intact structures of the terminal and internal hairpin loops, respectively, play important roles in forming the initial kissing and extending complexes between the ctRNA and target mRNA and that these regulate the copy number of this plasmid.

• 한국콘텐츠학회논문지
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• 제10권1호
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• pp.468-476
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• 2010

최근 우리나라는 미디어법의 통과로 인하여 미디어의 영향력이 더욱 증가하게 되었다. 그러나 미디어문화의 발전과 체계적인 미디어교육 시스템이 갖추어져 있지 않은 것이 현실이다. 이제는 단순한 ICT활용 교육에서 벗어나 새로운 미디어문화를 만들어갈 수 있는 교육적 역할 제시를 위해 비판적이고, 창조적인 미디어교육의 새로운 패러다임을 만들어 가야 한다. 본 연구는 미디어교육이 학교 밖에서 뿐만 아니라 학교 내의 공교육으로까지 올바른 미디어교육의 활성화와 체계적인 시스템을 만들어 가기 위한 방법으로 통합적 미디어교육을 담당하는 교사들을 위한 새로운 전문인 양성 교육과정을 제안하고자 한다. 지금까지 진행되어져 왔던 단편적이고 비체계적인 미디어교육 시스템에서 벗어나, 좀 더 전문적이고 체계적이며 구체적 방법인 미디어 리터러시 영역, 미디어스토리텔링 영역, 미디어제작 영역 등의 세 가지의 교육단계로 교육과정을 나누어 제시하였다.

• Journal of Microbiology and Biotechnology
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• 제28권8호
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• pp.1247-1259
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• 2018

Raspberries are polyphenol-rich fruits with the potential to reduce the severity of the clinical signs associated with obesity, a phenomenon that may be related to changes in the gut microbiota. The aim of this study was to investigate the effect of raspberry supplementation on the fecal microbiota using an in vivo model of obesity. Obese diabetic db/db mice were used in this study and assigned to two experimental groups (with and without raspberry supplementation). Fecal samples were collected at the end of the supplementation period (8 weeks) and used for bacterial 16S rRNA gene profiling using a MiSeq instrument (Illumina). QIIME 1.8 was used to analyze the 16S data. Raspberry supplementation was associated with an increased abundance of Lachnospiraceae (p = 0.009), a very important group for gut health, and decreased abundances of Lactobacillus, Odoribacter, and the fiber degrader S24-7 family as well as unknown groups of Bacteroidales and Enterobacteriaceae (p < 0.05). These changes were enough to clearly differentiate bacterial communities accordingly to treatment, based on the analysis of UniFrac distance metrics. However, a predictive approach of functional profiles showed no difference between the treatment groups. Fecal metabolomic analysis provided critical information regarding the raspberry-supplemented group, whose relatively higher phytosterol concentrations may be relevant for the host health, considering the proven health benefits of these phytochemicals. Further studies are needed to investigate whether the observed differences in microbial communities (e.g., Lachnospiraceae) or metabolites relate to clinically significant differences that can prompt the use of raspberry extracts to help patients with obesity.

• 한국분무공학회지
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• 제5권3호
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• pp.17-26
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• 2000

The main parameter commonly used to evaluate spray distribution is spray angle. Spray angle is important because it influences the axial and radial distribution of the fuel. Spray angles were measured and compared for the two non-air assisted injectors such as 2hole-2stream 4hole-1stream injectors used for port fuel injection gasoline engines with n-heptane as a fuel by three different measuring techniques, i.e., digital image processing, shadowgraphy, and spray patternator, respectively. Fuel was injected with the injection pressures of 0.2-0.35 MPa into the room temperature and atmospheric pressure environment. In digital image processing approach, the selection of the transmittance level is critical to obtain the edge of spray and hence to measure the spray angle. From the measurement results by the shadowgraphy technique, it is dear that the spray angle is varied during the spray injection period. The measurement results from spray patternator show that the different spray angles exist in different region. Spray angle increases with the increase in the injection pressure. it is suggested that the spray angle and stream separated angle should be specified when spray is characterized for 2hole-2stream injector, because spray angle is much different though stream separated angle is same. It was also considerably affected by the measurement techniques introduced in this experimental work. However, the optimal axial distance for measuring the spray angle seems to be at least 60-80 mm from the injector tip for two non-air assisted injectors.

• 대한전자공학회논문지SP
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• 제46권6호
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• pp.16-25
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• 2009

본 논문은 HSI 컬러 모델에서 색상(Hue)의 주기성을 고려한 블록기반 영상분할 방법을 제안한다. 제안한 방법에서는 영역 병합 시 사용되는 영역의 색상 대푯값으로 색상의 평균 대신 중앙점을 사용하며, 영역 간 색상차를 계산하기 위해 단방향 거리를 사용한다. 그리고 기존방법에서 사용한 복잡하게 계산된 영역별 임계값을 파라메타를 통해 조절할 수 있는 간단하지만 효율적인 임계값으로 수정한다. 실험결과 제안한 방법의 분할결과가 질감 성분이나 붉은 색상을 가진 영역에서 기존 방법을 사용했을 때 보다 더 자연스러우며, 제안한 방법과 기존 방법으로 버클리 영상분할 데이터베이스에서 제공하는 자연영상들을 분할하여 평가값을 비교해 본 결과 제안한 방법이 기존방법에 비해서 더 우수함을 알 수 있었다.

• Imaging Science in Dentistry
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• 제48권2호
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• pp.111-119
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• 2018

Purpose: This study was conducted to evaluate the accuracy of linear measurements of 3-dimensional (3D) images generated by cone-beam computed tomography (CBCT) and facial scanning systems, and to assess the effect of scanning parameters, such as CBCT exposure settings, on image quality. Materials and Methods: CBCT and facial scanning images of an anthropomorphic phantom showing 13 soft-tissue anatomical landmarks were used in the study. The distances between the anatomical landmarks on the phantom were measured to obtain a reference for evaluating the accuracy of the 3D facial soft-tissue images. The distances between the 3D image landmarks were measured using a 3D distance measurement tool. The effect of scanning parameters on CBCT image quality was evaluated by visually comparing images acquired under different exposure conditions, but at a constant threshold. Results: Comparison of the repeated direct phantom and image-based measurements revealed good reproducibility. There were no significant differences between the direct phantom and image-based measurements of the CBCT surface volume-rendered images. Five of the 15 measurements of the 3D facial scans were found to be significantly different from their corresponding direct phantom measurements(P<.05). The quality of the CBCT surface volume-rendered images acquired at a constant threshold varied across different exposure conditions. Conclusion: These results proved that existing 3D imaging techniques were satisfactorily accurate for clinical applications, and that optimizing the variables that affected image quality, such as the exposure parameters, was critical for image acquisition.

• 한국안전학회지
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• 제33권4호
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• pp.111-118
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• 2018

Korea is facing a surge in the aging population, showing that population aged 65 and above will be accounted for 42.5% of the total population in 2065 with the emphasis on the over-80 population consisting of 19.2%. In response to this abrupt change in population structure, the number of traffic fatality accident referring to older driver as aged 65+ years had been increasing from 605 fatalities in 2011 to 815 fatalities in 2015 resulting in increases in 34.7% in oppose to happening to decreases in 17.2% about non-older driver. With Logit analysis based on Newton-Raphson algorithm utilizing older driver's traffic fatality data for the 2011-2015 years, it was found that the likelihood of an accident resulting in a fatality for super older driver aged 80 years and above considerably increased compared to other older driver with aging classification: 2.24 times for violation of traffic lane, 2.04 times for violation of U-turn, 1.48 times for violation of safety distance, 1.35 times for violation of obstacle of passing; also average annual increase of traffic accident cost related to super older driver was fairly increased rather than other older driver groups. Hence, this study proposes that improving and amending transport safety system and Road Traffic Act for super older driver needs to be urgently in action about license management, safe driving education, etc. when considering the increase of over-80 population in the near future. Also, implementing a social agreement with all ages and social groups to apply with advanced driver assistance system for older driver groups will be able to become a critical factor to enhance safe driving over the face of the country.

• 한국전기전자재료학회논문지
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• 제18권5호
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• pp.389-395
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• 2005

The etching technology of the high aspect ratio contact(HARC) is necessary at the critical contact processes of semiconductor devices. Etching the $SiO_{2}$ contact hole with the sub-micron design rule in manufacturing VLSI devices, the unexpected phenomenon of 'profile tilting' or 'bottom distortion' is often observed. This makes a short circuit between neighboring contact holes, which causes to drop seriously the device yield. As the aspect ratio of contact holes increases, the high C/F ratio gases, $C_{4}F_{6}$, $C_{4}F_{8}$ and $C_{5}F_{8}$, become widely used in order to minimize the mask layer loss during the etching process. These gases provide abundant fluorocarbon polymer as well as high selectivity to the mask layer, and the polymer with high sticking yield accumulates at the top-wall of the contact hole. During the etch process, many electrons are accumulated around the asymmetric hole mouth to distort the electric field, and this distorts the ion trajectory arriving at the hole bottom. These ions with the distorted trajectory induce the deformation of the hole bottom, which is called 'profile tilting' or 'bottom distortion'. To prevent this phenomenon, three methods are suggested here. 1) Using lower C/F ratio gases, $CF_{4}$ or $C_{3}F_{8}$, the amount of the Polymer at the hole mouth is reduced to minimize the asymmetry of the hole top. 2) The number of the neighboring holes with equal distance is maximized to get the more symmetry of the oxygen distribution around the hole. 3) The dual frequency plasma source is used to release the excessive charge build-up at the hole mouth. From the suggested methods, we have obtained the nearly circular hole bottom, which Implies that the ion trajectory Incident on the hole bottom is symmetry.