Lee K.M.,Seoul National University |
Lee K.M.,Republic of Korea Air Force |
Woo S.J.,Seoul National University |
Hwang J.-M.,Seoul National University
American Journal of Ophthalmology | Year: 2013
Purpose: To evaluate the morphologic characteristics of optic nerve head drusen. Design: Retrospective case series. Methods: setting: Institutional (Seoul National University Bundang Hospital). patients: Sixty-one patients with optic nerve head drusen. observation procedure: Visible and buried optic nerve head drusen were identified using funduscopy, whereas homogenous and nonhomogenous optic nerve head drusen were identified using spectral-domain optical coherence tomography images. Buried optic nerve head drusen were classified according to the size. main outcome measures: Classification of optic nerve head drusen. Results: Of 99 eyes in 61 patients, optic nerve head drusen were buried in 95 eyes and visible in 4 eyes. The patients with visible optic nerve head drusen were older on average than those with buried optic nerve head drusen (53.3 ± 8.6 years vs 13.5 ± 7.1 years; P <.001) and exhibited larger disc diameters (1643 ± 265 μm vs 1287 ± 185 μm; P =.016). All 4 eyes with visible optic nerve head drusen exhibited hyperreflective borders, which were not found in patients with buried optic nerve head drusen. Of 95 eyes with buried optic nerve head drusen, 64 eyes (67%) showed homogenous internal reflectivity, whereas 31 eyes (33%) showed nonhomogenous reflectivity with lobulations. Large optic nerve head drusen were associated with a small optic disc diameter, nonhomogenous internal reflectivity, a partial highly reflective border, intraretinal cysts, and increased temporal retinal nerve fiber layer thickness. Conclusions: Optic nerve head drusen have a diverse spectrum of spectral-domain optical coherence tomography findings associated with patient age and disc size. © 2013 by Elsevier Inc. All Rights Reserved.
Lee K.M.,Seoul National University |
Lee K.M.,Republic of Korea Air Force |
Hwang J.-M.,Seoul National University |
Woo S.J.,Seoul National University
Retina | Year: 2014
PURPOSE:: To describe the clinical features of hemorrhagic complications secondary to optic nerve head drusen (ONHD) using spectral domain optical coherence tomography (SD-OCT). METHODS:: Sixty-three consecutive patients with SD-OCT-documented ONHD who presented at Seoul National University Bundang Hospital from December 2009 to July 2012 were included. Full ophthalmologic examinations, including fundus photographs, SD-OCT, fundus angiography, and visual field tests were analyzed in a total of 101 ONHD-positive eyes from 63 patients. RESULTS:: Hemorrhagic ONHD complications were found in 7 eyes (7%) from a total of 101 eyes with ONHD. All of them had buried ONHD (visualized with SD-OCT) and myopia (mean spherical equivalent = -4.00 ± 2.35 diopters). Patients with ONHD hemorrhagic complications had smaller disk diameters than patients without hemorrhagic complications (1,308 ± 166 vs. 1,555 ± 217 μm, P = 0.004). Peripapillary hemorrhages were classified into the following 3 types based on SD-OCT findings: subretinal (6 eyes, 86%), retinal (5 eyes, 71%), and vitreous hemorrhage (4 eyes, 57%). Six patients (86%) complained of the recent onset of visual symptoms, but visual acuities at presentation were 20/20 in all patients. In the three patients who were followed up, most hemorrhages were absorbed without complications. CONCLUSION:: Peripapillary hemorrhage can often occur in patients with buried ONHD and small disk diameters. As SD-OCT can be used to visualize ONHD beneath hemorrhage, it is helpful with the differential diagnosis and follow-up evaluation.© Ophthalmic Communication society,Inc.
News Article | March 1, 2017
BERWYN, Pa.--(BUSINESS WIRE)--Triumph Group, Inc. (NYSE:TGI) was selected by Korea Aerospace Industries, Ltd. (KAI), to provide Airframe Mounted Accessory Drives (AMAD) on the new KF-X fighter aircraft. The contract is in support of the latest generation of the air superiority fighter, which is scheduled to make its first flight in mid-2022 and begin low-rate initial production in 2024. The KF-X program is slated to benefit the Republic of Korea Air Force and the Indonesian Air Force. “We are pleased to support the KF-X fighter program, which will replace the aging Korean fleet of F-4s and F-5s, as well as equip the Indonesian Air Force,” said Tom Holzthum, executive vice president of Triumph Integrated Systems. “This win will allow Triumph to showcase the extensive capability and experience of our Geared Solutions business.” Triumph Integrated Systems’ Geared Solutions site in Park City, Utah, will design and produce the AMADs, which receive and distribute engine power to operate generators, pumps and other aircraft systems, and also carry the main engine starter turbine. The AMADs on the KF-X fighter jet will feature the latest innovations in the company’s aircraft accessory gearbox product line. Triumph Group, Inc., headquartered in Berwyn, Pa., designs, engineers, manufactures, repairs and overhauls a broad portfolio of aircraft structures, components, accessories, subassemblies and systems. The company serves a broad, worldwide spectrum of the aviation industry, including original equipment manufacturers of commercial, regional, business and military aircraft and aircraft components, as well as commercial and regional airlines and air cargo carriers. More information about Triumph can be found on the company’s website at http://www.triumphgroup.com.
News Article | November 21, 2016
FORT WORTH, Texas, Nov. 21, 2016 /PRNewswire/ -- Lockheed Martin (NYSE: LMT) was awarded a $1.2 billion contract to upgrade 134 F-16 aircraft for the Republic of Korea Air Force (ROKAF). The upgrades are based on the advanced F-16V configuration. Among the enhancements are an Active...
Park J.,Republic of Korea Air Force |
Kim B.,Yonsei University |
Kim C.,Yonsei University |
Kim H.,Yonsei University
Journal of Computing in Civil Engineering | Year: 2011
A range of studies have shown that three-dimensional (3D)/four-dimensional (4D) computer-aided design (CAD) has positively impacted the productivity and safety of construction processes. However, its potential impact on the entire life cycle of construction projects has not yet been fully investigated. The opinions of construction professionals have generally been reported on the basis of one-time interviews during several case studies. No statistical approach has yet been adopted to examine the whole spectrum of views about 3D/4D CAD use in construction projects. This study presents a comprehensive statistical analysis about how construction engineers perceive the effectiveness of 3D/4D CAD during various tasks of the construction project life cycle. A focus group interview and a review of the literature produced a total of 35application areas in which 3D/4D CAD can possibly improve existing construction processes. We identified the areas in which 3D/4D CAD has a high potential to significantly enhance project results by using an importance-performance analysis (IPA) and a questionnaire-based survey involving 165respondents. These study results are expected to provide new business strategies for 3D/4D CAD by broadening its traditional application realm. © 2011 American Society of Civil Engineers.
Choi E.-H.,Republic of Korea Air Force |
Chun H.-Y.,Yonsei University
Asia-Pacific Journal of Atmospheric Sciences | Year: 2014
The generation mechanisms of convective gravity waves in the stratosphere are investigated in a three-dimensional framework by conducting numerical simulations of four ideal storms under different environmental conditions: one un-sheared and three constant low-level sheared basic-state winds with the depth of the shear layer of 6 km and the surface wind speeds (Us) of 8, 18, and 28 m s-1, using the Advanced Regional Prediction System (ARPS) model. The storms simulated under the un-sheared (Us = 0 m s-1), weakly sheared (Us = 8 and 18ms-1), and strongly sheared (Us = 28ms-1) basicstate winds are classified into single-cell, multicell, and supercell storms, respectively. For each storm, the wave perturbations in a control simulation, including nonlinearity and microphysical processes, are compared with those in quasi-linear dry simulations forced by diabatic forcing and nonlinear forcing that are obtained from the control simulation. The gravity waves generated by the two forcing terms in the quasi-linear dry simulations are out of phase with each other for all of the storms. The gravity waves in the control simulation are represented by a linear sum of the wave perturbations generated by the nonlinear forcing and diabatic forcing. This result is consistent with the results of previous studies in a two-dimensional framework. This implies that both forcing mechanisms are important for generating the convective gravity waves in the three-dimensional framework as well. The characteristics of the three-dimensional gravity waves in the stratosphere were determined by the spectral combination of the forcing terms and the wave-filtering and resonance factor that is determined from the basic-state wind and stability as well as the vertical structure of the forcing. © The Korean Meteorological Society and Springer 2014.
Risk Stratification For Axillary Lymph Node Metastases in Breast Cancer Patients: What Clinicopathological and Radiological Factors of Primary Breast Cancer Can Predict Preoperatively Axillary Lymph Node Metastases?
Yun S.J.,Republic of Korea Air Force
Ultrasound Quarterly | Year: 2016
ABSTRACT: This study was to investigate clinicopathological features including immunohistochemical subtype and radiological factors of primary breast cancer to predict axillary lymph node metastasis (ALNM) and preoperative risk stratification.From June 2004 to May 2014, 369 breast cancer patients (mean age, 54.7 years; range, 29–82 years) who underwent surgical axillary node sampling were included. Two radiologists retrospectively reviewed clinicopathological features, initial mammography, and initial breast ultrasonography (US). Univariate and multivariate logistic regression analyses were used to evaluate associations between ALNM and variables. Odds ratio with 95% confidence interval and risk of ALNM were calculated.Among 369 patients, 117 (31.7%) had ALNM and 252 (68.3%) had no ALNM revealed surgically. On multivariate analysis, four factors showed positive association with ALNM: the presence of symptoms (P < 0.001), triple-negative breast cancer subtype (P = 0.001), mass size on US (>10 mm, P < 0.001), and Breast Imaging Reporting and Data System category on US (≥4c, P < 0.001). The significant risk of ALNM was particularly seen in patients with two or more factors (2, P = 0.013; 3, P < 0.001; 4, P < 0.001).The estimated risks of ALNM increased in patients with two, three, and four factors with odds ratios of 5.5, 14.3, and 60.0, respectively.The presence of symptoms, triple-negative breast cancer subtype, larger size mass on US (>10 mm), and higher Breast Imaging Reporting and Data System category on US (≥4c) were positively associated with ALNM. Radiologically, US findings are significant factors that can affect the decision making process regarding ALNM. Based on risk stratification, the possibility of ALNM can be better predicted if 2 or more associated factors existed preoperatively. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved
Kim H.-S.,Republic of Korea Air Force
Experimental and Therapeutic Medicine | Year: 2013
Primary diffuse large B-cell lymphoma (DLBCL) of the testis is a rare subtype of testicular tumor. While the histomorphology of testicular DLBCL is well described, a paucity of information in the literature exists with regard to the cytological diagnosis of this subtype of tumor. Touch imprint specimens were obtained from a testicular DLBCL occurring in a 64-year-old man. The cytological features of imprints were compared with the results obtained from histological and immunohistochemical examinations. Smears obtained from the touch imprints exhibited a high cellular yield consisting of discretely arranged monomorphic large cells with irregular nuclear membranes, scant cytoplasm and conspicuous nucleoli. Histologically, the tumor consisted of discohesive neoplastic lymphocytes that infiltrated diffusely and produced a wide separation of intact seminiferous tubules. Diffuse, intense immunostaining for CD45, CD20, MUM1 and Ki-67 led to the diagnosis of primary DLBCL of the testis with a non-germinal center B-cell-like phenotype. Careful observation of the touch imprint specimens of testicular DLBCL revealed a high cellularity with a predominant single-cell pattern of monomorphic cells demonstrating irregular nuclear membranes and conspicuous nucleoli. In addition, DLBCL is capable of developing in the testis and forming a predominantly discohesive cell population, suggesting the presence of a lymphoid malignancy. Thus, it may be possible to detect morphological features that are characteristic of DLBCL using imprint cytology. To the best of our knowledge, this is the first study reporting the diagnosis of testicular DLBCL using touch imprint cytology.
Moon C.H.,Republic of Korea Air Force
British Journal of Ophthalmology | Year: 2016
Background The photorefractive keratectomy (PRK) is approved for Air Force pilots in several nations. The occupational environments of pilots in the Air Force are unique, including extremely high altitude, low oxygen tension, high ultraviolet light exposure and high G-force load. The short-term efficacy and safety of PRK for pilots are documented. However, the study for long-term visual and refractive outcomes of PRK in pilots is limited. Objective To investigate the long-term visual and refractive outcomes in a 4-year follow-up period after PRK in pilots with low to moderate myopia. Methods Thirty-eight eyes of 20 subjects that underwent PRK and recruited to Air Force pilot were evaluated preoperatively and at 3, 6, 12, 24, and 48 months postoperatively. Results The mean patient age was 21.42±0.75 years. The mean preoperative manifest refraction spherical equivalent (SE) was -1.51±1.15 diopters (D). At 4 years postoperatively, the mean SE was -0.29±0.51, 89.5% of eyes achieved 20/20 or better Snellen uncorrected visual acuity, 71.1% of eyes were within ±0.50 D of emmetropia. The refraction stabilised by 6 months and was maintained up to the 4-year follow-up stage. Conclusions PRK for pilots with low to moderate myopia is safe and effective in the long term. Highaltitude environmental stress exposure has no effect on the refractive stability after PRK.
Republic of Korea Air Force | Date: 2014-08-06
A laser shooting training system includes a target device including a target area and a camera for photographing the target area, and an analysis device for calculating a coordinate of a laser discharged to the target area based on an image photographed by the camera, and displaying a spotted position corresponding to the laser coordinate to a user display screen. The analysis device calculates a center coordinate of a laser area included in the image, corrects the center coordinate based on a correction value relating to a size of the laser area, and calculates the laser coordinate.