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Search Results: 1 - 10 of 5858 matches for " Ki-Hyun Jeon "
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A case of successful survival from ventricular free wall micro-rupture without surgery  [PDF]
Jae-Bin Seo, Ki-Hyun Jeon, Jin-Hyun Park, Sang-Hyun Kim, Joo-Hee Zo, Myung-A Kim, Woo-Young Chung
World Journal of Cardiovascular Diseases (WJCD) , 2013, DOI: 10.4236/wjcd.2013.32029

We report a case of successful survival from ventricular free wall rupture without surgery, which was not overt rupture but micro-rupture. The patient was diagnosed with acute myocardial infarction (AMI) and underwent primary percutaneous coronary intervention (PCI). Myocardial blood leakage could be detected on transthoracic echocardiography with intravenous infusion of contrast dye 3 days after PCI. This examination revealed that there was not overt perforation but diffuse fissure. Because of his critical condition, he was treated conservatively without surgery. Nevertheless, he survived eventually.

Experimental Demonstration of Masking Phenomena between Competing Odorants via an Air Dilution Sensory Test
Ki-Hyun Kim
Sensors , 2010, DOI: 10.3390/s100807287
Abstract: To simulate the occurrence of masking phenomena with the aid of an air dilution sensory (ADS) test, two types of odorant mixtures were prepared: (1) M2 with two individual odorants [H2S and acetaldehyde (AA)] and (2) M6 with six individual odorants (H2S and five aldehydes). The test results derived for samples containing single individual odorants at a wide range of concentrations are initially used to define the empirical relationship between the dilution-to-threshold (D/T) ratio and odor intensity (OI) scaling. Based on these relationships, the D/T ratios were estimated for each odorant with the same intensity as the synthetic mixture. The relative contribution of each odorant to such mixture is then assessed by comparing the estimated and measured D/T values. This stepwise test confirmed the dominance of certain compounds at a given OI rating. In the case of M2, H2S showed sensitive detection at high OI range, while AA did so at low end. The pattern of a competing relationship is also seen consistently from M6 between AA (low) and iso-valeraldehyde (IA: high OI range). The overall results thus suggest that the masking phenomena between strong odorants should proceed under competing relationships, if released at the same time.
The Averaging Effect of Odorant Mixing as Determined by Air Dilution Sensory Tests: A Case Study on Reduced Sulfur Compounds
Ki-Hyun Kim
Sensors , 2011, DOI: 10.3390/s110201405
Abstract: To learn more about the effects of mixing different odorants, a series of air dilution sensory (ADS) tests were conducted using four reduced sulfur compounds [RSC: hydrogen sulfide (H2S), methanethiol (CH3SH), dimethylsulfide (DMS), and dimethyldisulfide (DMDS)] at varying concentration levels. The tests were initially conducted by analyzing samples containing single individual RSCs at a wide range of concentrations. The resulting data were then evaluated to define the empirical relationship for each RSC between the dilution-to-threshold (D/T) ratio and odor intensity (OI) scaling. Based on the relationships defined for each individual RSC, the D/T ratios were estimated for a synthetic mixture of four RSCs. The effect of mixing was then examined by assessing the relative contribution of each RSC to those estimates with the aid of the actually measured D/T values. This stepwise test confirmed that the odor intensity of the synthetic mixture is not governed by the common theoretical basis (e.g., rule of additivity, synergism, or a stronger component model) but is best represented by the averaged contribution of all RSC components. The overall results of this study thus suggest that the mixing phenomenon between odorants with similar chemical properties (like RSC family) can be characterized by the averaging effect of all participants.
Data Hiding Method with Quality Control for Binary Images  [PDF]
Ki-Hyun Jung, Kee-Young Yoo
Journal of Software Engineering and Applications (JSEA) , 2009, DOI: 10.4236/jsea.2009.21003
Abstract: Secret data hiding in binary images is more difficult than other formats since binary images require only one bit repre-sentation to indicate black and white. This study proposes a new method for data hiding in binary images using opti-mized bit position to replace a secret bit. This method manipulates blocks, which are sub-divided. The parity bit for a specified block decides whether to change or not, to embed a secret bit. By finding the best position to insert a secret bit for each divided block, the image quality of the resulting stego-image can be improved, while maintaining low computational complexity. The experimental results show that the proposed method has an improvement with respect to a previous work.
Advanced Burst Mode Control to Reduce the Standby Power of Flyback Converter  [PDF]
Min-Sung Kim, Hyoung-Woo Kim, Ji-Hye Jang, Ki-Hyun Kim
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.51B025
Abstract: This paper we proposed advanced burst mode control technique to reduce the standby power consumption of the switch mode power supply (SMPS). To reduce the standby power consumption, most of the converter use burst mode or skip mode control technique. However Conventional standby mode control techniques have some problems such as audible noise and poor regulation. In proposed techniques, basically, the burst mode control technique is employed to reduce the fundamental switching frequency while limiting the peak drain current. But, in proposed technique, to improve the regulation characteristic, burst period of the proposed technique is shorter than that of the conventional burst mode technique. And also, to reduce the switching loss increase due to the short burst period, burst switching signal of the proposed technique is partially skipped. By using proposed advanced burst mode control technique, calculated standby power is 0.695W while standby power of the conventional burst mode control is 1.014W.
The Relative Performance of NDIR-based Sensors in the Near Real-time Analysis of CO2 in Air
Sudhir Kumar Pandey,Ki-Hyun Kim
Sensors , 2007, DOI: 10.3390/s7091683
Abstract: In this study, the reliability of NDIR-based sensors was explored by evaluatingthe comparability between measurement systems in the near real-time analysis of CO2. Forthis purpose, replicate analyses were performed using sensors of two different model types(H-550 and B-530, ELT Company, Korea). Three replicate data of each sensor typecollected continuously by side-by-side analysis in three second intervals (a duration of 304hour) were evaluated for the relative performance of NDIR sensors. The reproducibility ofsensors, when assessed by relative standard error (RSE %) values of all sensor units,showed moderate changes with time with the overall mean of 2.33%. When CO2measurements from all NDIR sensor units were evaluated by correlation analysis, theresults showed strong comparability, regardless of the model type. The overall results ofthis study suggest that NDIR sensors are reliable enough to produce highly comparabledata at least in a relative sense.
Sorptive Removal of Odorous Carbonyl Gases by Water
Ehsanul Kabir,Ki-Hyun Kim
The Scientific World Journal , 2010, DOI: 10.1100/tsw.2010.66
The Combined Application of Impinger System and Permeation Tube for the Generation of Volatile Organic Compound Standard Gas Mixtures at Varying Diluent Flow Rates
Ki-Hyun Kim,Janice Susaya,Jinwoo Cho,David Parker
Sensors , 2012, DOI: 10.3390/s120810964
Abstract: Commercial standard gas generators are often complex and expensive devices. The objective of this research was to assess the performance of a simplified glass impinger system for standard gas generation from a permeation tube (PT) device. The performance of the impinger standard gas generation system was assessed for four aromatic VOCs (benzene, toluene, ethylbenzene, and m-xylene; BTEX) at varying flow rates (FR) of 50 to 800 mL·min?1. Because actual permeation rate (APR) values deviated from those computed by the manufacturer’s formula (MPR), new empirical relationships were developed to derive the predicted PR (PPR) of the target components. Experimental results corrected by such a formula indicate that the compatibility between the APR and MPR generally increased with low FR, while the reproducibility was generally reduced with decreasing flow rate. Although compatibility between different PRs is at a relatively small and narrow FR range, the use of correction formula is recommendable for the accurate use of PT.
Improved Exploiting Modification Direction Method by Modulus Operation
Ki-Hyun Jung,Kee-Young Yoo
International Journal of Signal Processing, Image Processing and Pattern Recognition , 2009,
Abstract: The EMD method proposed by Zhang and Wang fully exploited modification directions. Modifications in different directions were used to represent different secret data. According to the experimental results, the highest capacity was demonstrated in the 5-ary notational system, where only one secret digit is embedded for each two pixels. But this is an inefficient method because it can be hidden more secret data without revealing to the human visual system. To improve an embedding capacity, Chang et al. proposed two-stage EMD method, Lee et al. restricted to 8-ary embedding for the EMD method, and also Lee et al. segmented the pair of cover data into two parts to embed higher secret data. But still have a room for hiding more secret data. This paper proposes an improved method of the EMD method to hide more secret data while maintaining ahigh PSNR value. The proposed method can embed secret bit on every pixel of cover data. The experimental results demonstrate that the proposed method has a high capacity and good visual quality.
Paraoxonase 1 Gene Polymorphism Does Not Affect Clopidogrel Response Variability but Is Associated with Clinical Outcome after PCI
Kyung Woo Park, Jin Joo Park, Jeehoon Kang, Ki-Hyun Jeon, Si-Hyuck Kang, Jung-Kyu Han, Sang Eun Lee, Han-Mo Yang, Hae-Young Lee, Hyun-Jae Kang, Bon-Kwon Koo, Byung-Hee Oh, Young-Bae Park, Hyo-Soo Kim
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0052779
Abstract: Background Paraoxonase (PON) is a high-density-lipoprotein (HDL) associated enzyme with antioxidative and anti-atherogenic property. Its function is associated with coronary artery disease and its activity genetically controlled. We evaluated whether genetic variation of PON-1 is associated with clinical outcome in a large cohort of Korean patients with drug-eluting stents implantation. Methods A total of 1676 patients with drug-eluting stent implantation were enrolled in the prospective CROSS-VERIFY cohort from June 2006 to June 2010. We genotyped the PON1-Q192R gene, measured clopidogrel on-treatment platelet reactivity (OPR), and analyzed lipid profiles. The primary endpoint was the composite of cardiac death, myocardial infarction, and stent thrombosis at 12 months. Results PON-1 genotyping data were available in 1336 patients. Since the Q-allele is associated with decreased PON-activity, we analyzed the outcome between patients with QQ/QR (815 patients, 61%) and those with RR-genotype (521 patients, 39%). After adjustment for common cardiac risk factors, the QQ/QR-genotype was an independent predictor of the primary thrombotic endpoint with an 11-fold increased risk (HR 11.6, 95% CI: 1.55–87.0), but not repeat revascularization (HR 1.12, 95% CI: 0.78–1.61). The QQ/QR-genotype was not associated with OPR (QQ/QR: 231±86 PRU vs. RR 236±82 PRU, p = 0.342) but higher small-dense LDL levels (1.20±0.12 mg/dL vs. 0.76±0.15 mg/dL, p = 0.027). The increased risk of thrombotic outcomes was more profound in acute coronary syndrome (ACS) patients compared with non-ACS patients. Conclusion PON1 Q-allele is an independent predictor of worse cardiovascular outcome independent of platelet function and is associated with significantly higher levels of small dense LDL-C.
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