Jung Hoon Park

Yonsei University, Sŏul, Seoul, South Korea

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Publications (22)34.88 Total impact

  • Jung Hoon Park · Jin Bae Park
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    ABSTRACT: The PCCR (Pupil Center Corneal Reflection) method became dominant for finding human's diverse eye gaze directions through the research on the eye tracking technology that has been done for a very long period of time. The initial studies on the eye tracking technology were related to the general human interface for operating equipment and devices, then it has been promoted to the field of various purposes such as a market research in a recent study analyzing customer's behaviors. In particular, a real time eye gaze tracking system is most important for many HCI applications including stereoscopic synthesis, intend extraction, behavior analysis and etc. In order to make an eye gaze tracking system to be real time, the system must have an efficient pupil detection algorithm and ambience-independent image processing as well as reduced complexity, small size and number of circuit components. This paper proposes a method for getting clean images compared to the previous systems to reduce image processing overhead. Because it also helps reducing the number of image frames to be dropped during the image processing, the proposed method can provide a sufficient performance even on a low cost hardware system by reducing the transmission traffic.
    No preview · Article · May 2015 · Computer Standards & Interfaces
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    ABSTRACT: Plants are photosynthetic organisms that depend on sunlight for energy. Plants respond to light through different photoreceptors and show photomorphogenic development. Apart from Photosynthetically Active Radiation (PAR; 400-700 nm), plants are exposed to UV light, which is comprised of UV-C (below 280 nm), UV-B (280-320 nm) and UV-A (320-390 nm). The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation. Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants. It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation. The important targets of UV radiation in plant cells are DNA, lipids and proteins and also vital processes such as photosynthesis. Recent studies showed that, in response to UV radiation, mitochondria and chloroplasts produce a reactive oxygen species (ROS). Arabidopsis metacaspase-8 (AtMC8) is induced in response to oxidative stress caused by ROS, which acts downstream of the radical induced cell death (AtRCD1) gene making plants vulnerable to cell death. The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death. Recently, molecular studies have revealed genes involved in response to UV exposure, with respect to programmed cell death (PCD).
    Full-text · Article · Jan 2013 · International Journal of Molecular Sciences
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    ABSTRACT: Peroxiredoxins (Prxs), which are classified into three isotypes in plants, play important roles in protection systems as peroxidases or molecular chaperones. The three Prx isotypes of Chinese cabbage, namely C1C-Prx, C2C-Prx, and C-PrxII, have recently been identified and characterized. The present study compares their molecular properties and biochemical functions to gain insights into their concerted roles in plants. The three Prx isotype genes were differentially expressed in tissue- and developmental stage-specific manners. The transcript level of the C1C-Prx gene was abundant at the seed stage, but rapidly decreased after imbibitions. In contrast, the C2C-Prx transcript was not detected in the seeds, but its expression level increased at germination and was maintained thereafter. The C-PrxII transcript level was mild at the seed stage, rapidly increased for 10 days after imbibitions, and gradually disappeared thereafter. In the localization analysis using GFP-fusion proteins, the three isotypes showed different cellular distributions. C1C-Prx was localized in the cytosol and nucleus, whereas C2C-Prx and C-Prx were found mainly in the chloroplast and cytosol, respectively. In vitro thiol-dependent antioxidant assays revealed that the relative peroxidase activities of the isotypes were CPrxII > C2C-Prx > C1C-Prx. C1C-Prx and C2C-Prx, but not C-PrxII, prevented aggregation of malate dehydrogenase as a molecular chaperone. Taken together, these results suggest that the three isotypes of Prx play specific roles in the cells in timely and spatially different manners, but they also cooperate with each other to protect the plant.
    No preview · Article · Jan 2012 · Moleculer Cells
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    ABSTRACT: Zinc finger-homeodomain proteins (ZF-HDs) have been identified in many plant species. In soybean (Glycine max), GmZF-HD1 functions as a transcription factor that activates the soybean calmodulin isoform-4 (GmCaM-4) gene in response to pathogens. Recently, we reported specific binding of GmZF-HD1 to a 30-nt A/T-rich cis-element which constitutes two repeats of a conserved homeodomain binding site, ATTA, within -1207 to -1128bp of the GmCaM-4 promoter. Herein, homeodomain sequences of the GmZF-HD1 protein were compared to those of other homeodomain proteins and characterized the specificity of DNA sequences in the interaction of the GmCaM-4 promoter with GmZF-HD1 protein. Considering the conservation of homeodomains in plants, the AG sequence within a 30-nt A/T-rich cis-element is required for binding of the GmZF-HD1 protein. Approximately 25-bp of A/T-rich DNA sequences containing an AG sequence is necessary for effective binding to the GmZF-HD1 protein. Taken together, the results support the notion that the GmZF-HD1 protein specifically functions in plant stress signalling by interacting with the promoter of GmCaM-4.
    Full-text · Article · Nov 2010 · Phytochemistry
  • Jung Hoon Park · Woo Jin Hyung · Seung Ho Choi · Sung Hoon Noh
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    ABSTRACT: One of the sites most frequently invaded by gastric cancer is the mesocolon; however, the UICC does not mention this anatomical site as an adjacent structure involved in gastric cancer. The purpose of this study was to characterize and classify mesocolon invasion from gastric cancer. We examined 806 patients who underwent surgery for advanced gastric carcinoma from 1992 to 2007 at the Department of Surgery, Gangnam Severance Hospital, Korea. Among these, patients who showed macroscopically direct invasion into the mesocolon were compared to other patients with advanced gastric cancer. The curability, number and extent of nodal metastasis, and the survival of the mesocolon invasion group were significantly worse than these factors in the T3 group. However, the survival of the mesocolon invasion group after curative resection was much better than that of patients who had incurable factors. Mesocolon invasion should be included in T4 for the staging of gastric cancer.
    No preview · Article · Mar 2010 · Journal of Surgical Oncology
  • Jung Hoon Park · Ki Young Kim · Sang Do Park
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    ABSTRACT: An oxygen transport ceramic membrane was prepared with La0.6Sr0.4TixFe1−xO3−δ (x = 0.2 and 0.3) oxides which was synthesized by polymerized complex method. In order to investigate the effects of Ti substitutions into lanthanum–strontium ferrites, material property, thermal expansion coefficient, oxygen permeation, electrical conductivity and phase stability were examined according to Ti contents. The thermal expansion coefficients of LSTF6428 and LSTF6437 were 25.76 × 10−6 K−1 and 21.32 × 10−6 K−1 in the temperature range of 973−1273 K, respectively. The oxygen permeation fluxes through a disk type dense membrane of LSTF6428 and LSTF6437 with 1.6 mm thickness increased exponentially with increasing temperature and were 0.17 mL min−1cm–2 and 0.13 mL min−1cm−2 with Ph = 0.21 atm (O2 rich side) and Pl = 10−5 atm (lean side) at 1223 K, respectively. In the result of phase stability test with various conditions such as He, H2/N2 and CO2 atmosphere, La0.6Sr0.4TixFe1−xO3−δ was confirmed to be more stable than La0.6Sr0.4Ti0.2Fe0.8O3−δ through XRD and SEM analysis.
    No preview · Article · Sep 2009 · Desalination
  • Jung Hoon Park · Won Sang Ra · Jin Bae Park · Tae Sung Yoon
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    ABSTRACT: A robust pinch detection algorithm which can be implemented in a cheap microprocessor is proposed for the development of a safety feature in the automotive power window system. To solve the problems caused by the performance degradation of a Hall sensor or real driving situations, the proposed algorithm makes use of the H ∞ state estimation technique. The motivation of this approach comes from the advantage that the H ∞ filter can minimize or bound the worst-case estimation error energy for all bounded energy disturbances. Herein, the pinch torque rate estimator is derived from applying the steady-state H ∞ filter to the augmented model, which includes the motor dynamics and an additional torque rate state. Then, to redesign an appropriate estimator for real-time implementation, the torque rate estimate can be calculated more efficiently than the previous method [1]. Experimental results verify that, with a small amount of computation, the proposed pinch detection algorithm provides fast pinch detection performance superior to the existing method. Furthermore, it guarantees robustness against the worst-case measurement noises.
    No preview · Article · Apr 2009 · International Journal of Control Automation and Systems
  • Jung Hoon Park · Ga Hyung Choi · Tae Sung Yoon · Jin Bae Park
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    ABSTRACT: The estimation of disturbance torque in the safety window system is important for peoplepsilas convenience. Mostly, this kind of system can estimate the torque of window traveling system using the output of a hall sensor. To set up a window torque estimation system, however, is normally complicate and expensive. In addition, the calculation process of a window torque from the hall sensor output has usually inaccuracy because of various noises. To tackle this inherent problems of the previous approaches, a new sensorless DC drive disturbance torque estimator based on the Kalman estimator is proposed. Aside from the existing methods which utilize a torque from the hall sensor output, the proposed algorithm detects the pinched condition using the a motor driving current. The suggested scheme is also able to produce more a reliable pinch alarm in stead of the previous method.
    No preview · Conference Paper · Nov 2008
  • Jung hoon Park · Sang do Park
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    ABSTRACT: The formation of nano-sized barium titanate powders by hydrothermal reaction between barium hydroxide octahydrate and hydrous titania was studied at various temperatures, times and reactant concentrations without mineralizer. FTIR, TGA, SEM, XRF, BET and XRD were used to investigate the effects of temperature, time and concentration (in reactivity, particle size, morphology and secondary phase of BaTiO(3) powder prepared hydrothermally. ne main impurities were BaCO(3), TiO(2), surface H(2)O and lattice OH(-) radical at low conversion while secondary phase such as the lattice hydroxyl radical and trace BaCO(3) remained at high conversion. As the temperature and time increased in low concentration reaction below 0.5 M, (he maximum conversion could not exceed 98% but the conversion increased with increasing concentration, reaching over 99% above 1.5 M. In addition, concentration of more than 1.5 M was favorable to smaller particle size, better sphericity and Ba/Ti ratio (sic) 1. Kinetic analysis by the Johnson-Mehl-Avrami plot shows hydrothermal reaction progresses through solidification path. Initially, dissolution-precipitation mechanism takes place to form the nuclei of BaTiO(3) through fast dissolution of TiO(2)center dot xH(2)O and reaction with Ba(2) ions and then the BaTiO(3) crystal begins to grow.
    No preview · Article · Jul 2008 · Journal of chemical engineering of Japan
  • Jung hoon Park · Sang do Park
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    ABSTRACT: Alaska coals were extracted with sub- and supercritical water (SCW) using a micro reactor. Conversion of coal was studied in the temperature range of 320-400 degrees C, pressure 15-30 MPa and water density 0.06-0.7 g/cm(3) for 0-2 h. The experiments were conducted to investigate the effects of reaction temperature, pressure and water density on gas and liquid products respectively. The results show that the coal conversion in supercritical condition was higher than in sub-critical condition. The hexane soluble liquid product of original coal reaches a maximum 18.8% in the reaction time of 90 min at 400 degrees C and 30 MPa. The contents of CO, CH(4), and H(2) form especially well at supercritical condition. It is seen that supercritical condition was favourable to the hydrogen formation. With the increase of temperature, the sulfur in coal releases into the liquid and gas effluents. And the sulfur removal in liquid effluents is much greater than that in gas effluents. Higher water density causes higher conversion due to promotion of hydrolysis in coal extraction.
    No preview · Article · Jul 2008 · Journal of chemical engineering of Japan
  • Jung Hoon Park · Sang Do Park
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    ABSTRACT: La0.6Sr0.4Co0.2Fe0.8O3−δ oxides were synthesized by citrate method and hydrothermal method. The oxides prepared by citrate method are perovskite type structure, while the oxides by hydrothermal method have a small amount of secondary phase in the powder. Pyrex glass seal and Ag melting seal provided reliable gas-tight sealing of disk type dense membrane in the range of operation temperature, but commercial ceramic binder could not be removed from the support tube without damage to the tube or membrane. Though the degree of gas tightness increases in the order of glass>Ag>ceramic binder, in the case of glass seal, the undesired spreading of glass leads to an interfacial reaction between it and the membrane and reduction of effective permeation area. The oxygen flux of La0.6Sr0.4Co0.2Fe0.8O3−δ membrane increases with increasing temperature and decreasing thickness, and the oxygen permeation flux through 1.0 mm membrane exposed to flowing air (P h =0.21 atm) and helium (P1=0.037 atm) is ca. 0.33 ml/cm2·min at 950 °C. X-ray diffraction analysis for the membrane after permeation test over 160 h revealed that La2O3 and unknown compound were formed on the surface of membrane. The segregation compounds of surface elements formed on both surfaces of membrane irrespective of spreading of glass sealing material.
    No preview · Article · Aug 2007 · Korean Journal of Chemical Engineering
  • Jung Hoon Park · Yong Ou Joung · Sang Do Park
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    ABSTRACT: Conversion and sulfur removal of coal in sub- and supercritical water was studied in a micro reactor in the temperature range of 340-400C and water density 0-0.27 g/cm3 for 0-90 min under N2 atmosphere. The experiments were conducted to investigate the effect of reaction temperature, pressure, time and density of water on the sulfur removal in gaseous and liquid effluents, respectively. The results show that supercritical condition is more effective than sub-critical condition to remove the sulfur from coal. It is possible to reduce 57.42% of the original sulfur in coal for the reaction time of 90 min at 400C and 30 MPa. The main gas containing sulfur in the gaseous effluent is not SO2 but H2S, irrespective of operating condition. The sulfur removal in liquid effluents is much greater than that in gas effluents. Compared with temperature, the influence of water density and pressure is less significant.
    No preview · Article · Mar 2007 · Korean Journal of Chemical Engineering
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    ABSTRACT: A conceptual design using computational fluid dynamics and experimental fabrication has been performed to develop an industrial inkjet head for micro-patterning on printed circuit boards. The measured displacement waveform from piezoelectric actuator by Laser Doppler Vibrometer was used as input data for the three-dimensional flow solver to simulate the droplet formation. The mechanism of droplet ejection from piezoelectric-type inkjet heads was investigated by simulating two-phase flows of the air and metal inks. As a preliminary approach, liquid metal jetting phenomena are identified by simulating droplet ejection, droplet formation, and wetting on the substrate in a consequent manner. Parametric studies are followed by the design optimization process to deduce key factors to inkjet head performance: nozzle geometry, droplet size, ejecting speed, ejecting frequency, and ink viscosity. The present design tool based on two-phase flow solver and experimental measurements has shown its promising applicability to various concept designs of industrial inkjet system for micro-patterning on electronic chips and boards.
    No preview · Conference Paper · Jan 2007

  • No preview · Article · Mar 2006 · American Journal of Medical Genetics Part A
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    ABSTRACT: To determine whether 5,10-methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) genotype is associated with male infertility. Analysis of cytogenetic, Y chromosomal microdeletion assay (Yq), and the C677T and A1298C polymorphisms of the MTHFR gene by pyrosequencing and PCR-Restriction Fragment Length Polymorphism (RFLP) method. SAS 8.1 assessed the statistical risk of MTHFR genotype. The homozygous (T/T) C677T polymorphism of the MTHFR gene was present at a statistically high significance in unexplained infertile men with normal karyotype, instead at no significance in explained infertile men with chromosomal abnormality or Y chromosome deletion. There was no statistically significance of A1298C variation in infertile males. The MTHFR 677TT genotype may be a genetic risk factor for male infertility, especially with severe OAT and non-obstructive azoospermia in unexplained infertile males.
    No preview · Article · Nov 2005 · Journal of Assisted Reproduction and Genetics
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    ABSTRACT: As a preliminary work for the preparation of nylon 6/clay nanocomposites by reactive extrusion, nylon 6/clay nanocomposites were prepared by anionic polymerization in a flask. In order to investigate the effect of the intercalation of clay layers, the clay feeding times, such as in pre-mixing where the clay was fed before initiation of polymerization and in after-mixing method where the clay was fed after initiation of polymerization, were changed. The appearance of the WAXD peak of nanocomposites prepared by the pre-mixing method was obvious and the tensile strength was decreased compared with that of pure nylon 6, which indicates that the clay layers were not dispersed and distributed. During the preparation of the nanocomposites by the after-mixing method, disordering of the clay layers was observed with increasing clay addition time and was suspected to result from the rapid polymerization of nylon 6 within the clay layers. Keywordsanionic polymerization–nanocomposite–intercalation–disordering–nylon
    No preview · Article · Oct 2005 · Macromolecular Research
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    ABSTRACT: To investigate the XIST gene expression and its effect in a Klinefelter's patient, we used Klinefelter's syndrome (XXY) patient with azoospermia and also used a normal male (XY) and a normal female (XX) as the control, We were performed cytogenetic analysis, Y chromosomal microdeletion assay (Yq), semi-quantitative RT-PCR, and the Northern blot for Klinefelter's syndrome (KS) patient, a female and a male control, We extracted total RNA from the KS patient, and from the normal cells of the female and male control subjects using the RNA prep kit (Qiagen), cDNA microarray contained 218 human X chromosome-specific genes was fabricated. Each total RNA was reverse transcribed to the first strand cDNA and was labeled with Cy-3 and Cy-5 fluorescein, The microarray was scanned by ScanArray 4000XL system. XIST transcripts were detected from the Klinefelters patient and the female by RT-PCR and Northern blot analysis, but not from the normal male, In the cDNA microarray experiment, we found 24 genes and 14 genes are highly expressed in KS more than the normal male and females, respectively. We concluded that highly expressed genes in KS may be a resulted of the abnormal X inactivation mechanism.
    Preview · Article · Jan 2004

  • No preview · Article · Sep 2003 · Fertility and Sterility
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    Jung Hoon Park · Sung Je Hong · Jong Kim · Sunggu Lee
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    ABSTRACT: Applications with closed membership require membership control, which means that only authorised sources can send multicast packets and only registered members can receive them. However, IP multicast does not provide membership control since any user can send and receive multicast packets. We propose MUlticast with MEmbership Control (MUMEC), a multicast protocol with membership control.
    Preview · Article · Feb 2003 · Electronics Letters
  • Jung Hoon Park · Sang Do Park
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    ABSTRACT: The effects of reaction temperature, pressure and residence time were investigated with a flow apparatus. Cellobiose decomposition kinetics and products in suband supercritical water were examined at temperatures from 320 to 420 °C at pressures from 25 to 40 MPa, and at residence times within 3 sec. Cellobiose was found to decompose via hydrolysis and pyrolysis. The yield of desired hydrolysis product, glucose, was the maximum value of 36.8% at 320 °C, 35 MPa, but the amount of 5-(hydroxymethyl)furfural (HMF), fermentation inhibitor increased too because residence time increased in the subcritical region owing to decrease of reaction rate. Meanwhile, though the yield of glucose is low in the supercritical region, the yield of HMF decreased compared with the subcritical region; and at the minimum yield of HMF (380 °C, 25 MPa), the yield of glucose was 21.4%. The decomposition of cellobiose followed first-order kinetics and the activation energy for the decomposition of cellobiose was 51.05 kJ/mol at 40MPa.
    No preview · Article · Nov 2002 · Korean Journal of Chemical Engineering

Publication Stats

191 Citations
34.88 Total Impact Points


  • 2008-2015
    • Yonsei University
      • Department of Electrical and Electronic Engineering
      Sŏul, Seoul, South Korea
  • 2010-2013
    • Gyeongsang National University
      • • Division of Applied Life Science
      • • Plant Molecular Biology and Biotechnology Research Center
      Shinshū, Gyeongsangnam-do, South Korea
  • 2002-2009
    • Korea Institute of Energy Research
      Sŏul, Seoul, South Korea
  • 2007
    • Samsung Electro-Mechanics
      Sŏul, Seoul, South Korea
  • 2005-2006
    • CHA University
      • College of Medicine
      Sŏul, Seoul, South Korea
  • 2002-2005
    • Korea University
      • Department of Chemical and Biological Engineering
      Seoul, Seoul, South Korea
  • 2003
    • Pohang University of Science and Technology
      • Department of Electrical and Computer Engineering
      Geijitsu, North Gyeongsang, South Korea