Sung Yong Park

Korea Institute of Construction Technology, Kōyō, Gyeonggi-do, South Korea

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Publications (111)185.27 Total impact

  • Sung Yong Park, Jae Woo Chung, Seung-Yeop Kwak
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    ABSTRACT: We develop a regenerable anti-fouling membrane via the formation of a dynamic peel-and-stick of hydrophilic poly(ethylene glycol) (PEG) layer onto the surface of a poly(tetrafluoroethylene) (PTFE) membrane, using thermo-responsive reversible covalent bonding. In order to attach a peelable-and-stickable hydrophlilic layer onto a membrane surface, a maleimide end-modified PEG layer is coupled with a furan-modified PTFE membrane by reversible Diels–Alder (DA) cycloaddition reaction. The combined results of attenuated total reflection Fourier-transform infrared (ATR FT-IR), X-ray photoelectron spectroscopy (XPS) and field-emission scanning electron microscopy (FE-SEM) measurements clearly reveal that the maleimide end-modified PEG is successfully coupled with the furan-modified PTFE membrane surface by DA reaction. In addition, the hydrophilic PEG layer is readily and repeatedly reformed on the membrane surface by a thermally driven dynamic peel-and-stick process. The PEG-coupled PTFE membrane shows effective anti-fouling performance against a highly concentrated silica colloidal aqueous solution. In particular, the anti-fouling property is remarkably recovered after regeneration of the hydrophilic layer through the peel-and-stick process.
    Journal of Membrane Science 05/2015; 491. DOI:10.1016/j.memsci.2015.05.007 · 4.91 Impact Factor
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    ABSTRACT: We develop an anti-scaling ultrafiltration/microfiltration (UF/MF) membrane by introducing a high-density positive charge to a poly(vinylidene fluoride) (PVDF) membrane to suppress membrane scaling in Ca2+/silica-rich wastewater. Positively charged modifiers are synthesized by conjugating an amphiphilic polymer (Brij S10) and branched poly(ethylene imine) (b-PEI) at various molar ratios, and these are then implanted to PVDF membranes during the phase-inversion process. Attenuated total reflection Fourier-transform infrared (ATR FT-IR) spectra reveal that the positive modifiers successfully anchors onto the surface of the membrane by hydrophilic-hydrophobic phase recognition. As introducing the positive charge on the membrane surface, the membranes show positive surface charge and their pure water permeability (PWP) increases due to the protonation of b-PEI. Anti-scaling properties are also confirmed to be improved by filtration tests using a metal ions/silica-rich feed solution, which results from the repulsion of metal ion by the positively charged branch on the membrane. In addition, the water flux recovery by simple membrane backwashing of the modified membrane is double that of the neat PVDF membrane.
    Journal of Membrane Science 04/2015; 480. DOI:10.1016/j.memsci.2015.01.041 · 4.91 Impact Factor
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    ABSTRACT: Prestressed Concrete Wire and Strand (PC) strands are the most used materials to introduce prestress in a Pre-Stressed Concrete (PSC) structure. However, it is difficult to evaluate the final prestress force of the PC strand after prestressing or its residual prestress force after completion of the structure on site. This impossibility to assess eventual loss of prestress of the PC strand has resulted in a number of serious accidents and even in the collapse of several structures. This situation stresses the necessity to maintain the prestress force residual or after prestressing for the evaluation of the health of the concrete structure throughout its lifespan. Recently, several researchers have studied methods enabling one to verify the prestress force by inserting an optical fiber sensor inside the strand but failed to provide simple techniques for the fabrication of these devices to fulfill measurement performance from the design prestress to failure. Moreover, these methods require the additional installation of electrical resistance strain gages, displacement sensors and load cells on the outer surface of the structure for long-term precise measurement. This paper proposes a method enabling one to evaluate precisely and effectively the prestress force of the PC strand and intends to verify the applicability of the proposed method on actual concrete structures. To that end, an innovative PC strand is developed by embedding a Fiber Bragg Grating (FBG) sensor in the core wire of the PC strand so as to enable short term as well as long term monitoring. The measurement performance of the developed strand is then evaluated experimentally and the reliability of the monitoring data is assessed.
    Sensors 01/2015; 15(1):1060-70. DOI:10.3390/s150101060 · 2.05 Impact Factor
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    ABSTRACT: Prestressed concrete (PSC) is one of the most reliable, durable and widely used construction materials, which overcomes the weakness of concrete in tension by the introduction of a prestress force. Smart strands enabling measurement of the prestress force have recently been developed to maintain PSC structures throughout their lifetime. However, the smart strand cannot give a representative indication of the whole prestress force when used in multi-strand systems since each strand sustains a different prestress force. In this paper, the actual distribution of the prestress force in a multi-strand system is examined using elastomagnetic (EM) sensors to develop a method for tracking representative indicators of the prestress force using smart strands.
    Sensors 01/2015; 15(6):14079-92. DOI:10.3390/s150614079 · 2.05 Impact Factor
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    ABSTRACT: Conventional laser accelerated proton beam has broad energy spectra. It is not suitable for clinical use directly, so it is necessary for employing energy selection system. However, in the conventional laser accelerated proton system, the intensity of the proton beams in the low energy regime is higher than that in the high energy regime. Thus, to generate spread-out-Bragg peak (SOBP), stronger weighting value to the higher energy proton beams is needed and weaker weighting value to the lower energy proton beams is needed, which results in the wide range of weighting values. The purpose of this research is to investigate a method for efficient generating of the SOBP with varying magnetic field in the energy selection system using a carbon-proton mixture target. Energy spectrum of the laser accelerated proton beams was acquired using Particle-In-Cell simulations. The Geant4 Monte Carlo simulation toolkit was implemented for energy selection, particle transportation, and dosimetric property measurement. The energy selection collimator hole size of the energy selection system was changed from 1 to 5 mm in order to investigate the effect of hole size on the dosimetric properties for Bragg peak and SOBP. To generate SOBP, magnetic field in the energy selection system was changed during beam irradiation with each beam weighting factor. In this study, our results suggest that carbon-proton mixture target based laser accelerated proton beams can generate quasi-monoenergetic energy distribution and result in the efficient generation of SOBP. A further research is needed to optimize SOBP according to each range and modulated width using an optimized weighting algorithm.
    Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine 08/2014; 37(4). DOI:10.1007/s13246-014-0292-7 · 0.85 Impact Factor
  • Hoonhee Hwang, Sung Yong Park
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    ABSTRACT: In this paper, the results of basic tests conducted to evaluate the flexural behavior of lap-spliced joints that exploit the remarkable bonding performance of ultra-high performance concrete (UHPC) are presented. The effects of varying the lap-spliced length and joint length on the flexural behavior of the test members were examined. The failure pattern, load–deflection relationship, and load–strain relationship obtained by the static loading test were then analyzed with respect to the details of the joints. The results suggest lower bounds for the major test variables. A modified model, which considers the bonding performance of UHPC at the joint interface and the yield behavior of the reinforcement, is suggested on the basis of analytical models proposed for UHPC sections in previous studies. The corresponding results for this model are then compared with the test results.
    Canadian Journal of Civil Engineering 07/2014; 41(7). DOI:10.1139/cjce-2013-0281 · 0.41 Impact Factor
  • Engineering 01/2014; 06(12):743-749. DOI:10.4236/eng.2014.612072
  • Engineering 01/2014; 06(13):1000-1006. DOI:10.4236/eng.2014.613090
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    ABSTRACT: Purpose We evaluated the glass dosimeter suitability as an external audit program in proton therapy beam. A feasibility test of the glass dosimeter postal dose intercomparison was performed for high-energy proton beam use in radiation oncology with the collaboration of five proton therapy centers (Shizuoka Cancer Center, University of Florida Proton Center, MD Anderson Cancer Center, Loma Linda University Medical Center, and University of Pennsylvania School of Medicine). Material and methods The dosimetric properties of a GD-301 glass dosimeter were investigated for its potential use for postal dosimetry. Measurements were performed in a water phantom using a stair-like holder specially designed for this study. The depth-dose distribution measured with the glass dosimeter was compared to those from GEANT4 Monte-Carlo simulation. The GEANT4 code was also used to simulate the influence of holder material in the absorbed dose by inserting the glass dosimeter in a water phantom within the stair-like holder. We investigated the methodology of the absorbed dose determination with the glass dosimeter system establishing the calibration factor and various correction factors (non-linearity, fading, energy, holder). The participating proton therapy centers were asked to irradiate the glass dosimeter to 2 Gy with similar setup and conditions. Results The repeatability and dose rate dependence is within 1.2% and 1.5%, respectively. Depth-dose distributions in the pristine Bragg curve and the spread-out Bragg curve were estimated to be within 3%, compared with depth-dose measured with the ionization chamber. The difference in absorbed dose between the glass dosimeter and ionization chamber was within ±2% as a function of proton beam quality, residual ranges were between 2.1 and 9.0 cm. The influence of the holder material in absorbed doses of the proton beams is less than 1%. In the accuracy evaluation of the glass dosimeter system established in blind test, we obtained within 2.5% agreements with the ionization chamber dosimetry for the proton beam. In this feasibility study, the results on the proton beam output check are relatively good within ±6% for all participating centers. Conclusion We believe that the glass dosimeter system has considerable potential to be used for a postal dose audit program in proton beam.
    Radiation Measurements 12/2013; 59:66–72. DOI:10.1016/j.radmeas.2013.10.004 · 1.14 Impact Factor
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    ABSTRACT: One-lung ventilation (OLV) is accomplished with a double-lumen tube (DLT) or a bronchial blocker (BB). The authors compared the effectiveness of lung collapse using DLT, BB, and BB with the disconnection technique. Prospective, randomized, blind trial. A university hospital. Fifty-two patients undergoing elective pneumothorax surgery. Patients were assigned randomly to 1 of 3 groups: The DLT group (group 1), the BB group (group 2), and the BB with the disconnection technique group (group 3). The authors modified the disconnection technique in group 3 as follows: (1) turned off the ventilator and opened the adjustable pressure-limiting valve, allowing both lungs to collapse and (2) after loss of the CO2 trace on the capnograph, inflated the blocker cuff and turned on the ventilator, allowing only dependent-lung ventilation. Five and ten minutes after OLV, the degree of lung collapse was assessed by the surgeon, who was blinded to the isolation technique. The quality of lung collapse at 5 and 10 minutes was significantly better in groups 1 and 3 than in group 2. No significant differences were observed for the degree of lung collapse at any time point between groups 1 and 3. The average time for loss of the CO2 trace on the capnograph was 32.3±7.0 seconds in group 3. A BB with spontaneous collapse took longer to deflate and did not provide equivalent surgical exposure to the DLT. The disconnection technique could be helpful to accelerate lung collapse with a BB.
    Journal of cardiothoracic and vascular anesthesia 11/2013; 28(4). DOI:10.1053/j.jvca.2013.07.019 · 1.48 Impact Factor
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    ABSTRACT: We develop a sustainable anti-biofouling ultrafiltration membrane nanocomposites by covalently immobilizing silver nanoparticles (AgNPs) onto poly(vinylidene fluoride) (PVDF) membrane mediated by a thiol-end functional amphiphilic block copolymer linker. Field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDXS) measurements reveal that the AgNPs are highly bound and dispersed to the PVDF membrane due to the strong affinity of the AgNPs with the thiol-modified block copolymeric linkers, which have been anchored to the PVDF membrane. The membrane performs well under water permeability and particle rejection measurements, despite the high deposition of AgNPs on the surface of membrane. The Ag-PVDF membrane nanocomposite significantly inhibits the growth of bacteria on the membrane surface, resulting in enhanced anti-biofouling property. Importantly, the AgNPs are not released from the membrane surface due to the robust covalent bond between the AgNPs and the thiolated PVDF membrane. The stability of the membrane nanocomposite ensures a sustainable anti-biofouling activity of the membrane.
    ACS Applied Materials & Interfaces 10/2013; 5(21). DOI:10.1021/am402855v · 5.90 Impact Factor
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    ABSTRACT: The aim of this work was to study the feasibility of proton radiography (pRad) as a patient-specific range compensator (RC) quality assurance (QA) tool and to validate its clinical utility by performing QA on RCs having three kinds of possible defects. In order to achieve pRad for a single EBT film, proton beam currents were modulated with new weighting factors, maximizing the linearity of optical-density-to-thickness ratio. Two RCs, examined to be accurately manufactured as planned, were selected to estimate the feasibility of our pRad. The optical densities of the EBT film on which the RC was irradiated with the modulated proton beam were digitized to pixel values (pv) and then converted to thickness using a thickness-pv calibration curve. The thickness information on the pRad was compared with plan data that had been extracted from treatment planning system. The mean thickness difference (TD) over the flat RC regions was calculated as 0.39 mm, and the standard deviation as 0.22 mm, and the proton scattering effect was analyzed by step phantom measurement. Even proton scattering effected a TD of over 1 mm in the large gradient region, the percentage of pixels over the acceptance criterion was only within 1.11% and 3.49%, respectively, when a 1 mm distance to agreement tolerance limit was applied. The QA results for both precisely and imprecisely manufactured RCs demonstrated the high potential utility and clinical applicability of the pRad-based RC QA tool.
    Physics in Medicine and Biology 09/2013; 58(18):6511-6523. DOI:10.1088/0031-9155/58/18/6511 · 2.92 Impact Factor
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    ABSTRACT: The Korea Institute of Construction Technology has developed a precast FRP-concrete composite deck to be applied to cable-stayed bridges. This deck is a precast structural system in which concrete is disposed at the upper part and a hollow FRP tube is disposed at the bottom to play the role of tensile reinforcement and form. This paper presents the prototype of the so-developed FRP-concrete composite deck fabricated for trial construction. Electrical resistance sensors and optical fiber sensors were installed on the prototype to evaluate its structural stability and serviceability during the 17 months of operation through a series of field loading tests. From the field loading test results, the FRP-concrete composite deck was verified to secure sufficient structural stability and serviceability along the 17 months of operation even after the repeated passage of the heavy construction trucks. Besides, it appeared also that, for long-term monitoring, the optical fiber sensor provided more reliable measurement than the electrical resistance sensor glued to the structure.
    Key Engineering Materials 09/2013; 577-578:601-604. DOI:10.4028/www.scientific.net/KEM.577-578.601 · 0.19 Impact Factor
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    ABSTRACT: To investigate the accuracy of Eclipse treatment planning system (TPS) dose calculations at the surface. It is desirable to know the accuracy of the proton treatment planning system in predicting dose at superficial region. All measurements were performed in a clinical proton beam at the National Cancer Center in Korea. Proton treatment plans were developed for a superficial planning target volume (PTV) contoured on a cylindrical polymethylmethacrylate phantom specially designed for this study. Dose was then measured at the surface and also in the PTV for these treatment plans and compared against the TPS calculations. For our study, a model GD-301 glass dosimeters were used. The proton treatment planning system overestimated the superficial dose without use of bolus as much as by 7–14% when compared to glass dosimeter. On the other hand, with use of bolus to cover the superficial region, surface dose between the calculation from Eclipse and measurement using the glass dosimeter are approximately within 3%.
    Radiation Measurements 08/2013; 55:60-63. DOI:10.1016/j.radmeas.2013.02.015 · 1.14 Impact Factor
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    ABSTRACT: PURPOSE: To evaluate the retinal thickness and volume measured with the enhanced depth imaging (EDI) method compared with those measured with the conventional method using spectral-domain optical coherence tomography (OCT). DESIGN: Retrospective, observational, case-control study. METHODS: Clinical records of 20 healthy subjects and those of 35 patients with chorioretinopathy (central serous chorioretinopathy, polypoidal choroidal vasculopathy, Vogt-Koyanagi-Harada disease, and reticular pseudodrusen) were analyzed retrospectively. All subjects underwent spectral-domain OCT using both the conventional and the EDI OCT raster scan protocols. The raster scan was composed of 31 B-scans that were 9.0 mm in length and 240 μm apart. Retinal thickness and volume of 9 Early Treatment Diabetic Retinopathy Study subfields were investigated. Intraclass correlation coefficients, Bland-Altman plots, and Wilcoxon signed-rank test results were used for the analysis. RESULTS: Sixty-five eyes of 35 patients with chorioretinal diseases and 40 eyes of 20 normal healthy subjects were evaluated. The automatically measured retinal thickness and volume of 9 Early Treatment Diabetic Retinopathy Study subfields with conventional and EDI raster scan showed an intraclass correlation coefficient of 0.861 to 0.995 and 0.873 to 0.995, respectively. The 95% limits of agreement between the 2 protocols in the measurement of central subfield were -14.52 to 12.88 μm in retinal thickness and -0.014 to 0.013 mm(3) in retinal volume. The differences of segmentation error rate between the 2 protocols were statistically insignificant (P > .05), except in eyes with reticular pseudodrusen in the subgroup analysis (P = .006). No significant differences were observed in measured values between healthy eyes and unaffected fellow eyes. CONCLUSIONS: The EDI OCT raster scan showed high agreement with conventional OCT in the measurement of retinal thickness and volume and could be used to evaluate both the retina and choroid in normal eyes and in eyes with some forms of chorioretinal disorder.
    American Journal of Ophthalmology 06/2013; 156(3). DOI:10.1016/j.ajo.2013.04.027 · 4.02 Impact Factor
  • Canadian Journal of Civil Engineering 06/2013; 40(6). DOI:10.1139/cjce-2013-0248 · 0.41 Impact Factor
  • Source
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    ABSTRACT: Ten plans for Ir 192 high-dose-rate intracavitary radiotherapy (ICR) after 30 { 40 Gy external beam radiotherapy were investigated. The ICR prescription dose for each insertion was 4 or 5 Gy to point A twice weekly and the total dose of ICR ranged from 24 to 30 Gy (median: 24). A fractional 100 % dose was prescribed to point A. Two sets of CT images, before and after packing, were acquired at the rst ICR session with artifact-free applicators in place. The International Commission on Radiation Units and Measurements Report 38 (ICRU-38) rectal and bladder points and the percentage of volumes receiving 50 %, 80 % and 100 % of the prescribed dose were analyzed and compared. Conventional point A plans were performed. The mean values of the bladder and rectal ICRU-38 point doses before packing, 109.93 % and 117.80 %, were lower after packing, 98.85 % and 94.93 %, respectively, with the dierence not being signicant (p = 0.013). The maximum point doses of the bladder and rectum were decreased by 20.12 % and 16.01 %, respectively. The mean-volume fractions of the bladder receiving 50 %, 80 % and 100 % of the reference dose were decreased by 8.29 %, 4.48 % and 2.64 % while the decrease of the mean-volume fractions for the rectum were relatively small at 4.44 %, 1.52 % and 1.20 %, respectively. However, this reduction was not signicant based on a p value of about 0.15 $ 0.81. While the dose at the reference point was decreased signicantly due to the packing eects, the presence or the absence of packing had little eect on volumetric doses because the volumes enlarged by the packing eects were relatively small compared to the volume of either the entire bladder or the rectum itself. Packing is still needed as it could reduce the complications caused by the high point dose and decrease the maximum dose. PACS numbers: 87.53.Jw, 87.53.Tf Keywords: Intravaginal packing, Intracavitary radiotherapy £ E-mail: suhsanta@catholic.ac.kr -250-Intravaginal Packing Eects of CT-Guided Intracavitary¡ ¡ ¡ { Doo-Hyun Lee et al. -251-Fig. 1. ICRU report-38 recommended reference points of the bladder and the rectum.
    Journal- Korean Physical Society 03/2013; 54:250-254. DOI:10.3938/jkps.54.250 · 0.43 Impact Factor
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    ABSTRACT: Purpose: To evaluate the transit dose based patient specific quality assurance (QA) of intensity modulated radiation therapy (IMRT) for verification of the accuracy of dose delivered to the patient.Methods: Five IMRT plans were selected and utilized to irradiate a homogeneous plastic water phantom and an inhomogeneous anthropomorphic phantom. The transit dose distribution was measured with radiochromic film and was compared with the computed dose map on the same plane using a gamma index with a 3% dose and a 3 mm distance-to-dose agreement tolerance limit.Results: While the average gamma index for comparisons of dose distributions was less than one for 98.9% of all pixels from the transit dose with the homogeneous phantom, the passing rate was reduced to 95.0% for the transit dose with the inhomogeneous phantom. Transit doses due to a 5 mm setup error may cause up to a 50% failure rate of the gamma index.Conclusions: Transit dose based IMRT QA may be superior to the traditional QA method since the former can show whether the inhomogeneity correction algorithm from TPS is accurate. In addition, transit dose based IMRT QA can be used to verify the accuracy of the dose delivered to the patient during treatment by revealing significant increases in the failure rate of the gamma index resulting from errors in patient positioning during treatment.
    Medical Physics 02/2013; 40(2):021725. DOI:10.1118/1.4788658 · 3.01 Impact Factor
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    ABSTRACT: The behavioral characteristics of axially loaded precast FRP-concrete composite decks have been examined through flexural tests in order to verify the applicability to cable stayed bridge. The deck of a cable stayed bridge is naturally subjected to compressive forces. However, the precast FRP-concrete composite deck exhibits a small concrete section resisting to compression. Moreover, the deck is vulnerable to compression with a reduced cross-sectional stiffness because FRP of the deck under compression is governed by a compressive elastic modulus smaller than its tensile modulus. The results of the bending test on the axially loaded deck revealed a loss of the cross-sectional stiffness of about 5–13% but without effect on the serviceability. In addition, since large compressive stress is developed in concrete due to the axial load, the contribution of the axial load should be considered during the selection of the range where the precast FRP-concrete composite deck will be applied. From this study, it is verified that the precast FRP-concrete composite deck can be used as deck system for cable stayed bridge.
    Composites Part B Engineering 01/2013; 44(1):679–685. DOI:10.1016/j.compositesb.2012.01.079 · 2.98 Impact Factor
  • Engineering 01/2013; 05(11):856-864. DOI:10.4236/eng.2013.511104

Publication Stats

677 Citations
185.27 Total Impact Points

Institutions

  • 2010–2015
    • Korea Institute of Construction Technology
      Kōyō, Gyeonggi-do, South Korea
    • Soonchunhyang University
      Onyang, Chungcheongnam-do, South Korea
    • Samsung Medical Center
      • Department of Radiation Oncology
      Sŏul, Seoul, South Korea
    • Chosun University
      Gwangju, Gwangju, South Korea
  • 1997–2015
    • Seoul National University
      • • Department of Materials Science and Engineering
      • • School of Mechanical and Aerospace Engineering
      • • Center for Theoretical Physics
      Sŏul, Seoul, South Korea
  • 2013
    • Sungkyunkwan University
      • Department of Ophthalmology
      Sŏul, Seoul, South Korea
  • 2009–2013
    • Ajou University
      • Department of Anesthesiology and Pain Medicine
      Sŏul, Seoul, South Korea
  • 2012
    • Great Lakes Institute of Technology
      Flint, Michigan, United States
  • 2005–2012
    • National Cancer Center Korea
      • • Specific Organs Cancer Branch
      • • Colorectal Cancer Branch
      Kōyō, Gyeonggi Province, South Korea
  • 2011
    • McLaren Regional Medical Center
      Michigan City, Indiana, United States
  • 2002
    • Inha University
      • Department of Electronic and Electrical Engineering
      Seoul, Seoul, South Korea