스펙트럼 도메인 빛간섭단층촬영에서 발생하는 오류

김형준,정혜원,김형찬,Hyung Jun Kim,Hyewon Chung,Hyung Chan Kim 대한안과학회 2011 대한안과학회지 Vol.52 No.8

Purpose: To report frequencies of image artifacts associated with spectral-domain optical coherence tomography (SD-OCT) and to evaluate the impact of artifacts on foveal thickness measurements. Methods: This retrospective study included 267 eyes of 267 patients who underwent OCT volume scanning using Spectralis HRA+OCT (Heidelberg Engineering, Heidelberg, Germany). Macular volume scans of normal and diseased eyes were systematically evaluated for image artifacts within each scan overall and within the center 1-mm area. The frequency of each artifact type was compared for scans stratified by diagnosis category. Results: Among the volume scans, 79.4% had at least 1 artifact overall, and 26.6% had at least 1 artifact in the center 1-mm area. The highest percentage of inner retina misidentification occurred in the epiretinal membrane (36.1%), whereas the highest percentage of outer retina misidentification occurred in neovascular age-related macular degeneration (wet AMD, 40.0%). Clinically significant artifacts involving the center 1-mm area were observed in 6.4% of volume scans and were most common in wet AMD (43.3%). Conclusions: Image artifacts in SD-OCT volume scanning are common, but relatively less common in the center 1-mm area of scans. Clinicians should carefully review scans for artifacts when using SD-OCT images and retinal thickness measurements because clinically significant artifacts may affect retinal thickness measurements. J Korean Ophthalmol Soc 2011;52(8):943-951

인공지능 기반 가상 비서의 BIM 설계 적용에 관한 기초연구

김형준(Kim, Hyung?Jun),전한종(Jun, Han-Jong) 대한건축학회 2018 대한건축학회 학술발표대회 논문집 Vol.38 No.1

In this research, in order to solve the problem of degradation of business efficiency of building design utilizing BIM, a process was constructed using virtual assistant based on artificial intelligence technology. In the constructed process, the designer can learn the command customized to the virtual assistant applied to the BIM architecture design work, using the A-BIM algorithm. These A-BIM algorithms are utilized in the form of artificial intelligence algorithms built in the understanding structure of the designer. As a result, it is expected that the efficiency of operations can be improved by fusing the conventional artificial intelligence technology and the A-BIM algorithm, rather than developing artificial intelligence to be applied to the field of BIM architectural design.

이민기와 플루오렌기를 주쇄에 함유하는 고분자의 광기전 성질

김형준,이정효,곽찬규,진성호,이택승,Kim, Hyung-Jun,Lee, Jung-Hyo,Kwak, Chan-Kyu,Jin, Sung-Ho,Lee, Taek-Seung 한국섬유공학회 2008 한국섬유공학회지 Vol.45 No.1

New polyimine derivative containing fluorene group in the main chain was synthesized via Suzuki cross-coupling polymerization, reduction, and imine formation reaction, consecutively. The synthesized polymer was characterized and explored as organic photovoltaic cell device. The imine polymer P3 in diluted chloroform solution emitted red light (582 nm), whereas its precursor polymers P1 and P2 showed green (about 530 nm) and blue fluorescence (477 nm), respectively. Bulk heterojunction photovoltaic cells fabricated by blending P3 with the fullerene derivative PCBM was found to have a power conversion efficiency of upto 0.0005%, while cells from blending P3 with MEH-PPV yielded 0.0008% of power conversion efficiency.

Torulopsis bombicola 에 의해 생산된 생계면활성제의 특성에 관한 연구

김형준,류정용,박돈희 ( Hyung Jun Kim,Jeong Yong Ryu,Don Hee Park ) 한국화학공학회 1995 화학공학의이론과응용 Vol.1 No.2

팬터그래프-전차선로 접촉부 영상처리 기술 개발

김형준,박영,조용현,조철진,김인철,Kim, Hyung-Jun,Park, Young,Cho, Yong-Hyeon,Cho, Chul-Jin,Kim, In-Chol 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.12

The measurement of dynamic stagger in electric railways is one of the key test parameters to increase speed and maintain safety in electric railways. This paper is introduces a non-contact optical-based measuring instrument of a catenary system in electric railways. The instrument is implemented by utilizing a CCD (Charge Coupled Device) camera installed on the roof of a vehicle for vision acquisition and image processing techniques including the Canny edge detector and the Hough transform to detect contact wires and calculate dynamic stagger. To check the validity of our approach for the intended application, we measured stagger of a overhead wire of a Korea Tilting Train (TTX). The non-contact optical-based measurement system proposed in this paper performs real-time stagger measurement of an activated high-voltage contact wire. By results of this paper, the instrument should be applied to assess performance and reliability of newly developed electric railway vehicles.

진당원(珍糖元)의 고혈당 조절 작용 및 기전에 관한 연구

김형준,윤철호,정지천,Kim, Hyung-Jun,Yoon, Cheol-Ho,Jeong, Ji-Cheon 대한한방내과학회 2004 大韓韓方內科學會誌 Vol.25 No.2

Objective : Diabetes is a disease in which the body does not produce or properly use insulin. Etiological studies of diabetes and its complications showed that oxidative stress might playa major role. Therefore, many efforts have been made to regulate oxygen free radicals for treating diabetes and its complications. Because Jindangwon has been known to be effective in treatment of diabetes, the methanol extract of Jindangwon was tested for its effectiveness in reducing the oxidative stress induced by Streptozotocin. Methods : Jindangwon was washed, dried in the shade and crushed. The crushed Jindangwon was extracted 3 times, each time with 3 volumes of methyl alcohol at $60^{\circ}C$ for 24 hours. The extract was filtered and evaporated under reduced pressure using a rotary evaporator to yield 30.6 g. Jindangwon extract was oral-administered to the diabetic rats induced by streptozotocin 50 mg per 1 kg of body weight for 15 days. The efficacy of the Jindangwon extract was examined with regard to the enzymatic pathways involved in the oxygen free radical production and the glutathione balance. Results : he effects of the methanol extract of Jindangwon in streptozotocin-induced diabetics rats with regard to body weight, blood glucose level, hepatic lipid peroxide level, hepatic xanthine oxidase activity and type conversion rate, hepatic glutathione level, hepatic glutathione peroxidase activity, hepatic glutathione reductase activity, hepatic aldose reductase activity, and hepatic sorbitol dehydrogenase activity were favorable enough to suggest that it is a cure for diabetes and its complications. Conclusions :These results support Jindangwon as an effective reducing agent for oxidative stress in the tissues and organs by regulating the production of oxygen free radicals. Jindangwon, in particular, shows promising results for its use as a cure, or preventative medicine for diabetes and its complications by reducing oxidative stress in beta-cells of the pancreas.

진공 하에서 전기방사된 부직포의 특성에 대한 연구

김형준,정윤호,길명섭,김학용,방호주,Kim Hyung-jun,Jung Yoon-ho,Khil Myung-seob,Kim Hak-yong,Bang Ho-Ju 한국섬유공학회 2004 한국섬유공학회지 Vol.41 No.6

The exploitation of technologies based on electro spinning have been limited due to poor understanding of the process and consequent limitation in process control, productivity and reproducibility. To control the effect of the environmental parameter, which is one of important electro spinning parameters, the vacuum process was introduced because the magnitude of electric field in vacuum is not limited by the low dielectric breakdown strength of air. For this study, PCL dissolved in a mixture of N,N-dimethylformamide (DMF) and methylene chloride (MC) was electrospun as a form of nonwoven mats consisting of nano-sized fibers under vacuum and they have been analyzed using SEM and DSC. The PCL nonwoven mats via electrospinning under vacuum showed the characteristic spinning behavior observed at atmospheric pressure. In addition, results obtained from tensile test showed that PCL nonwoven mats via electro­spinning under vacuum have better mechanical properties than those prepared at atmospheric pressure.

강변저류지에 의한 홍수저감 효과 분석을 위한 수리실험

김형준,배덕원,윤광석,Kim,Hyung-Jun,Bae,Deok-Won,Yoon,Kwang-Seok 한국방재학회 2011 한국방재학회논문집 Vol.11 No.6

강변저류지는 홍수저감효과 뿐만 아니라 생태적인 목적으로도 활용이 가능하여 최근 강변저류지 설치에 관한 연구가 활발히 진행되고 있는 상황이다. 그러나, 강변저류지 설치에 따른 홍수저감효과는 기존에 개발된 수치모형에 의존하고 있으며, 수리모형을 통한 기초연구가 부족한 상황이다. 본 연구에서는 강변저류지의 홍수저감효과를 분석하기 위하여 부정류 수리실험을 수행하였다. 강변저류지 설계시 고려인자인 설치위치, 유입부 마루높이 및 강변저류지 면적 등을 수리실험에서 다양한 조건으로 반영하여 수리실험을 수행하였다. 강변저류지의 홍수저감효과는 설치위치가 가까운 경우 가장 효과가 클 것으로 판단되며, 월류부 마루높이는 최대한 낮게 설치하는 것이 홍수저감에 효과적인 것으로 나타났다. 강변저류지 면적이 커질수록 홍수저감효과 또한 증가하지만, 기대할 수 있는 최대저감효과는 한계값에 수렴할 것으로 판단된다. 본 연구를 통하여 관측되고 분석된 결과는 강변저류지 설계시 유용하게 활용될 수 있을 것으로 판단된다. Detention basin is highly effective hydraulic structure which is available for flood mitigation and ecological characteristics. However, analysis of flood mitigation by detention basin is performed with numerical approaches only, there is not enough data obtained by experimental observation. In this study, physical experiment were performed under unsteady flow condition to analyze flood mitigation with detention basin. Various design factors such as location, later weir height and extent of detention basin were considered in this experimental observations. As the distance from detention base to target location become closer and later weir height become higher, we can expect more effective flood mitigation. As the area of detention basin area become lager, we also expect more higher flood mitigation effects. But, the flood mitigation effects from detention basin would converged to critical value. The obtained data will be useful for following studies about detention basin.

말기암환자에서 혈청 비타민 C 농도와 연관된 인자들

김형준,황인철,염창환,안홍엽,최윤선,이재준,임수혁,Kim, Hyung Jun,Hwang, In Cheol,Yeom, Chang Hwan,Ahn, Hong Yup,Choi, Youn Seon,Lee, Jae Jun,Lim, Su Hyuk 한국호스피스완화의료학회 2014 한국호스피스.완화의료학회지 Vol.17 No.4

목적: 혈청 비타민 C 수치는 체내 항산화상태를 나타내는 지표로서, 암환자에서는 정상인에 비해 감소되어 있다. 하지만, 이 지표가 말기암환자에서 어느 정도 감소되어 있고, 그 감소에 어떤 요인들이 관련되는지에 대한 연구는 매우 드물다. 방법: 두 개 기관의 완화의료병동에 입원했던 암환자 65명을 대상으로 하였다. 환자의 나이, 성별, 암의 종류, 기능상태, 임상증상, 완치 목적의 암 치료력, 그리고 혈청 비타민 C를 포함한 혈액검사 자료를 수집하였다. 혈청 비타민 C 수치의 사분위수를 기준으로 두 군(3사분위수 이하 vs. 4 사분위수)으로 분류한 후 각 군의 차이를 비교하였고, 단계적 다중 로지스틱 회귀분석을 통해 혈청 비타민 C 수치와 관련된 인자를 확인하였다. 결과: 대상자의 혈청 비타민 C의 평균은 $0.44{\mu}g/mL$이었으며, 대상자 전체가 비타민 C 결핍에 해당되었다. 단변량 분석에서는, 비폐암 환자이거나(P=0.041) 발열이 있는 환자(P=0.034)에서 낮은 혈청 비타민 C 수치를 보였다. 폐암, 발열, 삼킴곤란, 호흡곤란, C 반응단백, 그리고 항암화학요법 등의 잠재적인 인자들을 보정한 다변량 분석에서, 낮은 혈청 비타민 C 수치를 나타낼 가능성은 항암화학요법을 받은 군에서 그렇지 않은 군에 비해 3.7배 높았고(P=0.046), 발열이 있는 군에서 그렇지 않은 군에 비해 7.22배 높았다(P=0.020). 결론: 말기암환자에서 비타민 C 부족은 매우 심각하였고, 항암화학요법 치료력과 발열이 관련 있었다. Purpose: Serum vitamin C is one of the indicators for antioxidant levels in the body and it is lower in cancer patients compared with the healthy population. However, there have been few studies on the levels of serum vitamin C in terminally ill cancer patients and related factors. Methods: We followed 65 terminal cancer patients who were hospitalized in two palliative care units. We collected data of age, sex, cancer type, functional status, clinical symptoms, history of cancer therapy, and various laboratory findings including serum vitamin C level. Patients were categorized into two groups according to the quartile of serum vitamin C level (Q1-3 vs. Q4), which were compared each other. Stepwise multiple logistic regression analysis was used to identify factors related to serum vitamin C levels. Results: The mean serum vitamin C level was $0.44{\mu}g/mL$, and all patients fell into the category of vitamin C deficiency. Univariate analysis showed that The serum vitamin C level was lower in non-lung cancer patients (P=0.041) and febrile patients (P=0.034). Multivariate analysis adjusted for potential confounders such as lung cancer, fever, dysphagia, dyspnea, C reactive protein, and history of chemotherapy demonstrated that odds for low serum vitamin C level was 3.7 for patients receiving chemotherapy (P=0.046) and 7.22 for febrile patients (P=0.02). Conclusion: Vitamin C deficiency was very severe in terminally ill cancer patients, and it was associated with history of chemotherapy and fever.

자동차부품 적용 저온분사 코팅기술

김형준,Kim, Hyung-Jun 대한용접접합학회 2006 대한용접·접합학회지 Vol.24 No.1