눈운동장애 없이 시력 저하를 보인 해면정맥동 내경동맥류 1예

김승훈,김선웅,김범태,장지호,Seung Hoon Kim,Sun Woong Kim,Bum-Tae Kim,Jee Ho Chang 대한안과학회 2012 대한안과학회지 Vol.53 No.3

Purpose: Oculomotor disturbance is the common manifestation of intracavernous carotid aneurysm cases. Intracavernous carotid aneurysms causing compressive optic neuropathy with no oculomotor disturbance are relatively rare due to their anatomical characteristics. We experienced a case of intracavernous carotid aneurysm which resulted in a shifted supraclinoid segment of the internal carotid artery, presenting with visual loss and visual field defect with no oculomotor disturbance. Case summary: A 40-year-old woman presented with loss of vision in the right eye. A relative afferent pupillary defect was observed in this eye. Visual field test showed quadranopsia in the right eye. Magnetic resonance imaging revealed that the intracavernous carotid aneurysm had shifted the supraclinoid segment of the internal carotid artery to the superomedial position. The right optic nerve was directly molded by the shifted supraclinoid segment of the internal carotid artery at the point of the bifurcation between the anterior cerebral artery and the middle cerebral artery. A Guglielmi detachable coil (GDC) embolization was performed successfully with no operational complications. Six months after coiling, best corrected visual acuity of the right eye was 1.0, and the visual field defect had recovered in all except the superior temporal field. Conclusions: Oculomotor disturbance is frequently associated with intracavernous carotid aneurysms. Nevertheless, optic neuropathy without oculomotor disturbance may be the only sign in patients with an intracavernous carotid aneurysm that causes shifting of the supraclinoid segment of the internal carotid artery. J Korean Ophthalmol Soc 2012;53(3):486-491

머신러닝 기반의 수도권 지역 고령운전자 차대사람 사고심각도 분류 연구

김승훈,임영빈,김기정,Kim, Seunghoon,Lym, Youngbin,Kim, Ki-Jung 한국디지털정책학회 2021 디지털융복합연구 Vol.19 No.4

고령화 시대에 따라 고령운전자 역시 증가하고 있으며, 이들에 의한 교통사고 심각성에 대한 관심이 높아지고 있다. 이에 고령운전자에 의한 사고심각도 예측 모형의 필요성이 점차 요구됨에 따라, 본 연구에서는 기계학습 기법을 활용하여 고령운전자에 의한 차대사람 사고심각도 예측을 위한 모형 정립 및 분석을 수행하고자 한다. 이를 위해 4개의 기계학습 알고리즘 (Logistic Model, KNN, RF, SVM)을 활용, 예측 모형을 개발하고 각 결과를 비교하였다. 연구 결과에 따르면 Logistic과 SVM 모형이 상대적으로 높은 예측력을 보였으며, 정확도 측면에서는 RF가 높은 것으로 나타났다. 추가적으로 각 중요 변수들을 이용하여 교차분석을 수행한 후 그 결과를 제시하였다. 본 연구의 결과들은 고령화시대에 고령운전자에 의한 사고심각성을 예방하기 위한 안전정책 및 인프라 개발에 활용될 것으로 판단된다. Moving toward an aged society, traffic accidents involving elderly drivers have also attracted broader public attention. A rapid increase of senior involvement in crashes calls for developing appropriate crash-severity prediction models specific to senior drivers. In that regard, this study leverages machine learning (ML) algorithms so as to predict the severity of vehicle-pedestrian collisions induced by elderly drivers. Specifically, four ML algorithms (i.e., Logistic model, K-nearest Neighbor (KNN), Random Forest (RF), and Support Vector Machine (SVM)) have been developed and compared. Our results show that Logistic model and SVM have outperformed their rivals in terms of the overall prediction accuracy, while precision measure exhibits in favor of RF. We also clarify that driver education and technology development would be effective countermeasures against severity risks of senior driver-induced collisions. These allow us to support informed decision making for policymakers to enhance public safety.

영상 스트리밍 서비스를 위한 우선순위 버퍼 혼잡제어 알고리즘

김승훈,최재원,최승식,Kim, Seung-Hun,Choi, Jae-Won,Choi, Seung-Sik 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.4B

최근 네트워크 기술이 발전하면서 사용자들의 요구가 다양화되고 대용량의 멀티미디어 데이터에 대한 필요성이 증가하고 있다. 실시간성과 동시성이 중요시 되는 멀티미디어 데이터의 전송에는 UDP(User Datagram Protocol) 트래픽이 사용되고 있는데, UDP 트래픽은 현재의 인터넷 기반인 TCP(Transmission Control Protocol) 트래픽과 경쟁 관계에 있어 네트워크의 혼잡을 초래하는 경우가 많았다. 반면 TCP 트랙픽은 네트워크의 혼잡제어를 수행하지만 수신자의 관점을 고려하지 않은 점이 있어서 스트리밍 전송에는 적합하지 않은 단점을 가지고 있다. 본 논문에서는 네트워크의 형평성 문제를 해결하고 수신자의 관점에서 RTP/RTCP(Real-time Trasport Protocol/Realtime Transport Control Protocol)를 기반으로 하는 네트워크 알고리즘을 제안한다. 네트워크에 우선순위를 적용하여 수신자의 버퍼를 고려한 혼잡제어 알고리즘인 POBA(Priority-Ordered Buffer Algorithm)는 시뮬레이션 결과를 통해 우선 순위가 없는 기존 네트워크에 비해 패킷 손실률과 버퍼 점유도 면에서 스트리밍 전송에 적합한 환경을 제공하고 있음을 확인할 수 있었다. According to the recent development of network technology, the demands of users are diversified and the needs of multimedia traffic are increasing. In general, UDP(User Datagram Protocol) traffic is used to transport multimedia data, which satisfied the real-time and isochronous characteristics. UDP traffic competes with TCP traffic and incur the network congestion. However, TCP traffic performs network congestion control but does not consider the receiver's status. Thus, it is not appropriate in case of streaming services. In this paper, we solve a fairness problems and proposed a network algorithm based on RTP/RTCP(Real-time Transport Protocol/Realtime Transport Control Protocol) in view of receiver status. The POBA(Priority Ordered Buffer Algorithm), which applies priorities in the receiver's buffer and networks, shows that it provides the appropriate environment for streaming services in view of packet loss ratio and buffer utilization of receiver's buffer compared with the previous method.

연속 CIP 공법으로 형성된 PUS 부재의 단면 설계 및 휨 강도 산정

김승훈,노삼영,홍성진,김갑수,한범석,Kim, Seung-Hun,Noh, Sam-Young,Hong, Seong-Jin,Kim, Kap-Soo,Han, Byum-Seok 대한건축학회 2012 대한건축학회논문집 Vol.28 No.6

Recently the Permanent Uni-wall System (PUS) has been developed which improved the disadvantage of the CIP and could be used as permanent retaining wall. The sections of PUS members are molded with circle casing form and deformed casing form. In the generality of cases, deformed casing section consists of reinforced concrete because of the concrete cover by code and the method of concreting with tremie pipe. But, circle casing section can be designed with various structural types which are steel, reinforced concrete, and steel reinforced concrete(SRC). In this study, design methods for PUS section were proposed and two types of PUS section were tested to investigate the flexural strength and behaviors. Variable was the details of circle casing section which were the deformed bars and the shear reinforcements surrounded H beam. All specimens failed due to concrete crushing. Specimen with SRC section in circle casing showed more ductile behavior after ultimate flexural strength than the other specimen. Nominal flexural strengths by section analysis and design code based on a strain-compatibility approach were compared with test results. These comparisons showed that PUS section possessed the flexural strength by design code.

몰드 오실레이터 이중구조 실린더의 정현파 진동 특성을 이용한 위치동기화 알고리즘 개발

김승훈,최두철,공남웅,김상우,Kim, Seung Hun,Choi, Doo Chul,Kong, NamWoong,Kim, Sang Woo 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.21 No.8

Improvement in the control strategy for continuous casting is a crucial requirement to enhance the slab's quality and to increase productivity. The mold oscillator adopts the dual cylinders due to its heavy weight, so the synchronized motion of two cylinders is an important aspect when precise control is needed. The conventional method uses the master-slave control applied to the valve input reference, but the synchronization performance should still be improved. This paper proposes a novel synchronization algorithm for dual cylinders used in a mold oscillator. The master-slave concept is applied to the target reference position, that is, the slave target reference position is controlled to match the slave cylinder's position with the master cylinder's position. In the simulation based on a Simulink model, the proposed algorithm shows a better synchronization performance in aspect of the mean of the absolute error and the peak synchronization error.

$(HF)_2(CO)$ 분자착물에 관한 Ab Initio 연구

김승훈,Kim, Seung Hoon 대한화학회 1998 대한화학회지 Vol.42 No.6

$6-31+G^{\ast}^{\ast}와\;6-311+G^{\ast}^{\ast}$의 기본조를 사용해서 이합체 분자착물 FH…FH, FH…CO, FH…OC 뿐만 아니라 $(HF)_2(CO)$의 형성가능한 두가지 삼합체 분자착물들에 대해서 HF-SCF, MP2 그리고 B3LYP 계산을 수행했다. 이 삼합체 분자착물들에 대한 여러 가지 바닥상태 성질들을 구하였으며, 대응하는 단위체들과 이합체들의 성질들과 비교하였다. FH…CO가 FH…OC에 비해 평균 0.85 kcal/mol 만큼 안정했고, F-H…F-H…C≡O가 F-H…F-H…O≡C 보다 1∼2 kcal/mol 만큼 안정한 것으로 계산되었다. 삼합체 분자착물 형성에 따른 C≡O stretching band 는 그들의 이합체들(FH…CO, FH…OC)에 비해 각각 24, $37\;cm^{-1}$만큼, H-F stretching band는 각각 $54, 353\; cm^{-1}$만큼 red shift 되는 것으로 평가되었다. The HF-SCF, MP2 and B3LYP calculations have been performed on the two conceivable clusters $(HF)_2(CO)$ trimers as well as their dimer complexes FH…FH, FH…CO and FH…OC applying $6-31+G^{\ast}^{\ast}$, and $6-311+G^{\ast}^{\ast}$ basis sets. A variety of ground state properties of these trimer complexes have been listed, and compared with corresponding properties of isolated monomers and combined dimers. It was calculated that FH…CO is more stable than FH…OC by average 0.85 kcal/mol and F-H…F-H…C≡O is more stable than F-H…F-H…O≡C by 1-2 kcal/mol. The C≡O stretching bands of the F-H…F-H…C≡O and F-H…F-H…O≡C were red shifted by 24, $37\;cm^{-1}$ compared with the FH…CO and FH…OC respectively. Also, H-F stretching bands were red shifted by 54 and $353\;cm^{-1}$.

류마티스 관절염 환자에서 Conserved T 세포 수용체의 CDR3 motif를 표현하는 제2형 콜라겐 특이 T세포주의 형성과 유지

김승훈,조미라,윤지희,박성환,조철수,황수연,김호연,Kim, Seung-Hoon,Cho, Mi-La,Youn, Jeehee,Park, Sung-Hwan,Hwang, Sue-Yun,Cho, Chul-Soo,Kim, Ho-Youn 대한면역학회 2001 Immune Network Vol.1 No.1

Background: To determine the molecular structure of type II collagen-specific T-cell receptors associated with rheumatoid arthritis (RA). Methods: We generated CII-specific T-cell lines of 8 RA patients by prolonged in vitro culture with bovine CII (bCII) and the immunogenic peptide (256-270) of human CII. The proliferation response towards CII stimulation was measured from the uptake of 3H-thymidine. Changes in the secretion of Th 1 and Th2 cytokines in the culture supernatent were measured by ELISA. The TCR clonotypes of these T-cells were examined by RT-PCR/SSCP analyses of all 22 $V_{\beta}$ chains. Results: T-cells from patients' tissue exhibited strong proliferation index upon CII stimulation, which was maintained up to 6 months in the culture. The secretion of INF-$\gamma$from these T-cells increased along with the duration of culture time, while the amount of IL-4 production did not show significant changes. The SSCP band patterns of patients' T-cells appear as discrete bands unlike the smeary streak produced from normal samples. Some SSCP bands, each representing selected expansion of a TCR containing certain subtype of $V_{\beta}$ peptides, appeared to be identical in more than one patients. Among these, the expansion of SSCP band representing the $V_{\beta}$ 14 CDR3 region persisted after switching the antigen to the immunogenic human peptide (256-270). Conclusion: CII-reactive T-cells expressing distinct CDR3 motifs are selectively expanded in the peripheral blood and synovial fluid of RA patients, and their persistent proliferation upon CII stimulation, as well as the production Th 1-type cytokines, may play pivotal roles in RA pathogenesis.

정시안에서 스펙트럼영역 빛간섭단층촬영기를 이용한 연령과 성별에 따른 황반 두께의 변화

김승훈,최경식,이성진,Seung Hoon Kim,Kyung Seek Choi,Sung Jin Lee 대한안과학회 2011 대한안과학회지 Vol.52 No.3

Purpose: To evaluate the changes in macular thickness with regard to age and gender in normal subjects with emmetropia using spectral domain optical coherence tomography. Methods: The present study consisted of 90 healthy subjects (162 eyes) with no ophthalmic evidence of retinopathy and who had emmetropic eyes. The data from macular measurements using spectral domain optical coherence tomography was analyzed according to the groups divided by age (Group 1: 0 to 19 years of age, Group 2: 20 to 39 years of age, Group 3: 40 to 59 years of age, Group 4: 60 to 80 years of age) and gender. Results: Macular thickness of the central circle was 253.40 ± 23.03 μm in all subjects. There was no significant change with age (p > 0.05). However, the measurements at the inner (3 mm) and outer circle (6 mm) showed a reduction of macular thickness with age (p < 0.05). The macular thickness at the central and inner circle was significantly lower in the female subjects (p < 0.05). In group 3 and 4, macular thickness at the central circle in males was greater than in females. In group 3, the average inner macular thickness in males was significantly greater than in females (p < 0.05). Conclusions: In normal subjects with emmetropia, there are statistically significant differences in macular thickness between subjects of different age and gender. The results from the present study can be expected to provide a reference value for evaluating macular disease. J Korean Ophthalmol Soc 2011;52(3):299-307

마이크로파를 이용한 급속 가열 연신 공정의 동역학 모델링과 정상상태 특성 해석

김승훈,백영남,허유,Kim, Seung-Hoon,Paik, Yeong-Nam,Huh, You 한국섬유공학회 2006 한국섬유공학회지 Vol.43 No.6

Fiber forming is an important technology for producing multi-functional goods that have a flexible and structured plane form by using raw material with special properties. This research reports on the metal fiber manufacturing technology that adopted induction heating and drawing, but without use of dies that are now installed in the conventional wire drawing processes. Heating wires allows the drawing process to build up necking and to shorten the process by reducing the process steps so that a new and efficient production method of metal fibers is to be conceived and developed. A new device that can process a single wire consists of three major parts: the drawing part comprised of capstans, that is, feeding roll and take-up roll with specially hardened circumferential surface, the change gear part with continuously controllable draw ratio, and the heating part that includes a heating source and an energy propagation channel and an electromagnetic wave absorber With this device feasibility of the induction heating method is tested and the characteristics of the metal wire drawing process is analyzed. Results show that the microwave can be applied to attenuate the metal wire as a heating source and the experimental profiles of the cross-sectional area in the heated drawing zone under a steady state condition coincide well with those from theoretical model. The diametric variation of the drawn wires increased, however, as the drawing ratio increased.

스펙트럼 영역 빛간섭단층촬영기를 이용한 근시 정도에 따른 황반 구조의 정량적 분석

김승훈,박주연,박태관,온영훈,Seung Hoon Kim,Joo Youn Park,Tae Kwann Park,Young-Hoon Ohn 대한안과학회 2011 대한안과학회지 Vol.52 No.11

Purpose: To investigate the correlation of macular retinal thickness and refractive error using spectral-domain optical coherence tomography (SD-OCT). Methods: A total of 120 eyes with no posterior abnormalities were enrolled in the present study. Subjects were divided into 3 groups based on their spherical equivalent. Visual acuity, refraction, slit lamp examination, tonometry and fundus examination were performed. Retinal thickness between the RPE and IS/OS junction was measured at the fovea, 1 mm (inner ring) and 2 mm (outer ring) superiorly, inferiorly, nasally and temporally using SD-OCT. Overall average thickness, average foveal thickness, and the inner and outer ring macular thickness were measured. Results: The average foveal thickness was significantly greater in the high myopic eyes than in the low to moderate myopic and emmetropic eyes (p = 0.001). However, the RPE-IS/OS junction thickness of the foveola and the outer macular thickness were significantly lower (p = 0.001, p = 0.002) in the high myopic eyes. There was a weak, but significant negative correlation between refractive error and average foveal thickness (r = -0.38, p = 0.001). A positive correlation was found between refractive error and the RPE-IS/OS junction thickness (r = 0.40, p = 0.001). Conclusions: Macular retinal thickness is related to refractive error in normal subjects. Effects of eyeball elongation are more apparent in high myopic eyes than in low to moderate myopic eyes. A significant decline in the RPE-IS/OS junction thickness suggests the photoreceptor outer segments in the foveola are damaged in high myopic eyes. J Korean Ophthalmol Soc 2011;52(11):1286-1295