웹 로그 분석을 통해 연관성 규칙을 활용한 개인화 상품 추천의 효과성 연구

임현성,이영재 한국경영정보학회 2002 한국경영정보학회 학술대회논문집 Vol.2002 No.-

Zero-valent Iron Enhances Acetate and Butyrate Production from Carbon Monoxide by Fonticella tunisiensis HN43

임현성,공다슬,Chae Ho Im,김창만,송영은,오상은,김중래 한국생물공학회 2023 Biotechnology and Bioprocess Engineering Vol.28 No.5

The use of carbon monoxide (CO) as a valuable feedstock for producing various platform chemicals through biorefinery processes has attracted considerable research interest. Acetate is an intermediate chemical synthesized from CO and CO2 through acetogenesis via the Wood– Ljungdahl pathway. Acetate can further serve as a substrate for chain elongation into a higher volatile fatty acid (VFA) when sufficient reducing power is provided. Zero-valent iron (ZVI) is used widely as a reducing agent in environmental remediation applications. This study established that the externally provided reducing power from ZVI oxidation increased the acetate production (approximately 13 times) from CO and the further synthesis of VFA. The effect of ZVI on CO/CO2 conversion was evaluated by quantifying the formation of acetate and butyrate. The carbon and electron balance provide information on the mechanism of C1 gas conversion and chain elongation. These findings highlight a useful intermediate production under the reducing power-limited bioprocesses, such as C1 gas bioconversion.

반복된 양안시 검사로 유발된 사위도 변화 분석

임현성,이은희,송윤영,정미아 한국융합학회 2018 한국융합학회논문지 Vol.9 No.12

양안시 검사를 반복하면서 검사횟수 증가로 유발된 피로도에 따른 사위도의 변화 정도를 파악하고자 하였다. 사시 및 기타 안질환 또는 전신질환이 없는 20대 성인 남녀 21명을 대상으로 양안시 검사를 실시하였다. 검사가 진행될수록 정위와 사위 모두에서 사위 정도가 증가함을 볼 수 있었다. 원거리의 경우 검사가 5회 반복되었을 때, 정위는 1.56△만큼 사위 량이 증가하였고 사위의 경우에서는 1.63△만큼 사위 량이 증가하였다. 근거리의 경우에는 검사가 5회 반복되었을 때, 정위는 1.78△만큼 사위 량이 증가하였고 사위의 경우에서는 2△만큼 사위 량이 증가하였다. 검사 횟수가 증가할수록 피로도가 증가함에 따라 결과 값이 정상범위에서 점진적으로 벗어나는 것으로 나타났으며, 변화의 정도가 실제 임상에서 잘못된 처방을 내릴 수 있을 정도라고 판단된다. 결론적으로 양안시 검사를 실시 할 때는 보다 정확하고, 신속하게 진행하여 검사를 하여야 한다는 것을 알 수 있었다. The purpose of this study was to evaluate the degree of heterophoria variations according to visual fatigue induced by increasing number of examinations while repeating binocular vision examinations. Twenty - one adults in their twenties who had no heterotropia other eye disease or systemic disease underwent binocular vision examinations. As the examinations progressed, the degree of heterophoria increased in both orthophoria and heterophoria. When the distance examinations was repeated 5 times, orthophoria increased degree of 1.56△ heterophoria. and heterophoria increased degree of 1.63△ heterophoria. When the near examinations was repeated 5 times, orthophoria increased degree of 1.78△ heterophoria. and heterophoria increased degree of 2△ heterophoria.. As the number of examinations increased, the result gradually deviated from the normal range as visual fatigue increased. The degree of the variation is judged to be enough to make the wrong prescription in the clinic. In conclusion, it was found that the binocular vision examinations should be conducted more accurately and promptly.

한국인에서 시신경유두주위 망막혈관분포와 망막신경섬유층의 형태학적 분석

임현성,백두진,김형찬,Hyun Sung Leem,Doo Jin Paik,Hyung Chan Kim 대한안과학회 2007 대한안과학회지 Vol.48 No.10

Purpose: The study present the central retina arterial supply, optic disc shape, RNFL (retinal nerve fiber layers) thickness and optic disc rim area. Methods: To evaluate the relationship between central retina artery pattern, optic disk shape, and RNFL thickness was measured using optical coherence tomography (OCT3000) and pattern of the central retinal artery were investigated by TRC50IX. Healthy Koreans (107 males, 97 females) were enrolled in this study. The classification is made by dividing surface of the nerve head into ten sector. Results: As a result of the shape of the optic disc divided into four group, vertically oval were 54%. The results showed the central retinal artery, in 252 eyes, had its origin in the center. None of the eyes had their origin on temporal side. RNFL thickness according to OCT parameter was superior, 127.6816.16 Conclusions: In summary, this study indicates that in healthy Koreans the shape of the optic disc is vertically oval and the origin of their central retinal artery is at the center. The RFNL thickness of both the superior and inferior quadrants was 127 m according to OCT.

고압직류송전(HVDC) 변환설비 검사기법에 관한 연구

임현성,한운기,정진수,박찬엄,송영상 대한전기학회 2013 대한전기학회 학술대회 논문집 Vol.2013 No.10

Central Corneal Thickness and Corneal Endothelial Cell Changes Caused by Contact Lens Use in Diabetic Patients

임현성,Ki Cheul Shin,이군자,김응권,서경률 연세대학교의과대학 2011 Yonsei medical journal Vol.52 No.2

Purpose: To analyze the effects of soft contact lenses on central corneal thickness and morphologic characteristics of the corneal endothelium in diabetic patients. Materials and Methods: Ultrasound pachymetry and noncontact specular microscopy were performed on 26 diabetic patients who regularly use soft contact lenses (group 1), 27 diabetic patients who do not use soft contact lenses (group 2) and 30 normal subjects (group 3). We compared the values in each group using the Mann-Whitney test. Results: The central cornea was found to be thicker in diabetic patients,both those who use and do not use contact lenses, than in the normal control group. The central corneal thickness was significantly higher in group 1 (564.73 ± 35.41 μm) and group 2 (555.76 ± 45.96 μm) than in the control group (534.05 ± 27.02 μm), but there was no statistically significant difference between groups 1 and 2. Endothelial cell density was significantly different between the groups, and was smallest in the group of diabetic patients using contact lenses. The coefficient of variation of cell size was significantly higher and the percentage of hexagonal cells was significantly lower in contact lens using diabetic patients than in non-contact lens using diabetic patients and in the control group. Conclusion: Central corneal thickness and endothelial cell density is more affected by diabetes mellitus,and corneal endothelial cell morphology is more affected by contact lens use, when compared with normal subjects.

GP 콘택트렌즈 착용자의 안경착용 실태에 관한 연구

임현성,이군자 대한시과학회 2008 대한시과학회지 Vol.10 No.4

Purpose : The purpose of this study was to survey on the wearing glasses and refractive errors in GP contact Jens user. Methods : we evaluated the refractive error and wearing conditions of the GP lens of 80 patients(male 18, female 62) from February 2006 to April 2007 on the Eye Clinic of K Hospital. Results : GP contact lens wearing time were daily over than lOhours 90%, 5 to 10hours 8.7%. 2 to 5hours 1.2%. Wearing time a day of have not glasses were 13.10±1.26 hours, wearing time a day of have glaases were 12.45±1.34hours. GP contact lens wearing time more Iong than wearing time have not glasses. Only contact lens wearers were 25% without eyeglass. difference of refractive error and spherical value of glasses were larger values of contact lens user than novice. Difference of refractive error and spherical value of glasses were larger vaJues of GPiens user in over one year than GPlens user in within one year. Conclusions : ln these results, majority of contact lens user were not recognized need corrected eyeglass. we knew that exchanged not glasses more Iong time GP contact lens users, accordingly, have not eyeglass were needed to educate thal contact lens wearer have to corrected eyeglass.

Isolation of Novel CO Converting Microorganism Using Zero Valent Iron for a Bioelectrochemical System (BES)

임현성,김창만,송영은,백지윤,임채호,김중래 한국생물공학회 2019 Biotechnology and Bioprocess Engineering Vol.24 No.1

Carbon monoxide (CO) is one of the main waste gas components of the steel industry and biomass gasification process. CO has also been highlighted as a feedstock for biological conversion to platform and valueadded chemicals. Conventional CO-converting strains have drawbacks of slow growth rate and high sensitivity to oxygen as well as low conversion yield. Most CO conversion microbes harbor the Wood-Ljungdahl pathway (WLP) and CO-dehydrogenase, and the reducing equivalent is significantly limited for acetyl-CoA synthesis. In this study, electrochemically active CO converting strains were isolated and characterized using zero valent iron (ZVI) granules (Fe0) as an external electron donor. The strains isolated from ZVI augmented enrichment could also use a carbon electrode as the electron donor, and simultaneously convert CO to acetate and VFAs in a bioelectrochemical system. From enrichment and isolation with ZVI, both Clostridium sp. HN02 and Fonticella sp. HN43 were isolated and showed higher performance for acetate production from CO in BES, and electrochemical activity by cyclic voltammetry.

Acetate and VFA production from carbon monoxide using zero valent iron

임현성,김창만,송영은,임채호,김중래 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

C1 gas has been highlighted for biorefinery process, and it is a valuable feedstock to produce various platform chemicals. The acetate is an intermediate chemical which can be synthesized via Wood-Ljundahl pathway, and further substrate for chain elongation into a higher VFA when sufficient reducing power provided. Hydrogen gas and reducing sugar have problem for providing reducing power for C1 gas conversion (e.g. high price and catabolite repression). ZVI has been widely used as a reducing agent in environmental process. In this study, we examined that the externally provided reducing power from ZVI oxidation, increase acetate production from CO and further synthesis of volatile fatty acids. The effect ZVI on CO/CO₂ conversion was evaluated with acetate production and byproduct formation. The carbon and electron balance provide an information for mechanism of C1 gas conversion and chain elongation. We have shown that ZVI can provide reducing power to microbial C1 gas conversion.

양안시 이상 환자에서 우세안과 주시안의 관계 분석

임현성,위대광,주석희 대한시과학회 2010 대한시과학회지 Vol.12 No.3

Purpose : We studied the relationship of dominant eye and fixing eye in heterophoria and heterotropia. Methods : Fifty-one subjects(Male: 21, Female; 30) were measured between seven to sixty three years, evaluated to alternate cover test after AR/K(Canon RK-Fl, Japan) measw·ed. Ocular dominance was determined using hole in-the-card test before measured in subjective refraction. Prism bar was determined using objective deviating tropia angle after refraction. Results : Intermitant heterotropia patients were the most 26 patients(Sl%) in binocular anomalies, equaled to dominant eyes and fixing eyes were 28 patients(55%), non equaled to dominant eyes and fixing eyes were 23 patients(45%). Alternated dominant eyes were searched in esotropia and exotropia each to one patient, esophoria patints were nothing. Dominant eyes had greater degree of myopia than nondominant eyes but show no significant difference between eyes(p=0.95), fixing eyes had lesser degree of myopia than nondfixing eyes but show no significant difference between eyes(p=0.88). Conclusions : The analysis showed that using a combination of dominant and fixing eye test because small deviating eyes would be likely to different from dominant eye to fixing eye, alternated fixing eyes.