• Korean Journal of Radiology
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• v.23 no.4
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• pp.389-401
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• 2022

Objective: This study aimed to determine a factor for predicting suboptimal image quality of the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI in patients with extrahepatic bile duct (EHD) cancer before MRI examination. Materials and Methods: We retrospectively evaluated 259 patients (mean age ± standard deviation: 68.0 ± 8.3 years; 162 male and 97 female) with EHD cancer who underwent gadoxetic acid-enhanced MRI between 2011 and 2017. Patients were divided into a primary analysis set (n = 184) and a validation set (n = 75) based on the diagnosis date of January 2014. Two reviewers assigned the functional liver imaging score (FLIS) to reflect the HBP image quality. The FLIS consists of the sum of three HBP features, each scored on a 0-2 scale: liver parenchymal enhancement, biliary excretion, and signal intensity of the portal vein. Patients were classified into low-FLIS (0-3) or high-FLIS (4-6) groups. Multivariable analysis was performed to determine a predictor of low FLIS using serum biochemical and imaging parameters of cholestasis severity. The optimal cutoff value for predicting low FLIS was obtained using receiver operating characteristic analysis, and validation was performed. Results: Of the 259 patients, 140 (54.0%) and 119 (46.0%) were classified into the low-FLIS and high-FLIS groups, respectively. In the primary analysis set, total bilirubin was an independent factor associated with low FLIS (adjusted odds ratio per 1-mg/dL increase, 1.62; 95% confidence interval [CI], 1.32-1.98). The optimal cutoff value of total bilirubin for predicting low FLIS was 2.1 mg/dL with a sensitivity of 95.1% (95% CI: 88.9-98.4) and a specificity of 89.0% (95% CI: 80.2-94.9). In the validation set, the total bilirubin cutoff showed a sensitivity of 92.1% (95% CI: 78.6-98.3) and a specificity of 83.8% (95% CI: 68.0-93.8). Conclusion: Serum total bilirubin before acquisition of gadoxetic acid-enhanced MRI may help predict suboptimal HBP image quality in patients with EHD cancer.

• Journal of Platform Technology
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• v.11 no.6
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• pp.68-78
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• 2023

In this paper, the color distortion in images with haze would be analyzed. When haze is included in the scene, the color signal reflected in the scene is accompanied by color distortion due to the influence of transmittance according to the haze component. When the influence of haze is excluded by a conventional de-hazing method, the distortion of color tends to not be sufficiently resolved. Khoury et al. used the dark channel priority technique, a haze model mentioned in many studies, to determine the degree of color distortion. However, only the tendency of distortion such as color error values was confirmed, and specific color distortion analysis was not performed. This paper analyzes the characteristic of color distortion and proposes a restoration method that can reduce color distortion. Input images of databases used by Khoury et al. include Macbeth color checker, a standard color tool. Using Macbeth color checker's color values, color distortion according to changes in haze concentration was analyzed, and a new color distortion model was proposed through modeling. The proposed method is to obtain a mapping function using the change in chromaticity by step according to the change in haze concentration and the color of the ground truth. Since the form of color distortion varies from step to step in proportion to the haze concentration, it is necessary to obtain an integrated thought function that operates stably at all stages. In this paper, the improvement of color distortion through the proposed method was estimated based on the value of angular error, and it was verified that there was an improvement effect of about 15% compared to the conventional method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.1082-1090
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• 2009

Peak expiratory flow rate(PEF) is a very important diagnostic parameter obtained from the forced vital capacity(FVC) test. The expiratory flow rate increases during the short initial time period and may cause measurement error in PEF particularly due to non-ideal dynamic characteristic of the transducer. The present study evaluated the initial rise slope($S_r$) on the flow rate signal to compensate the transducer output data. The 26 standard signals recommended by the American Thoracic Society(ATS) were generated and flown through the velocity-type respiratory air flow transducer with simultaneously acquiring the transducer output signal. Most PEF and the corresponding output($N_{PEF}$) were well fitted into a quadratic equation with a high enough correlation coefficient of 0.9997. But only two(ATS#2 and 26) signals resulted significant deviation of $N_{PEF}$ with relative errors>10%. The relationship between the relative error in $N_{PEF}$ and $S_r$ was found to be linear, based on which $N_{PEF}$ data were compensated. As a result, the 99% confidence interval of PEF error was turned out to be approximately 2.5%, which was less than a quarter of the upper limit of 10% recommended by ATS. Therefore, the present compensation technique was proved to be very accurate, complying the international standards of ATS, which would be useful to calibrate respiratory air flow transducers.

• Investigative Magnetic Resonance Imaging
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• v.18 no.2
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• pp.120-132
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• 2014

Purpose : To compare dynamic susceptibility contrast imaging, diffusion-weighted imaging, and susceptibility-weighted imaging (SWI) for the differentiation of tumor recurrence and delayed radiation therapy (RT)-related changes in patients treated with RT for primary brain tumors. Materials and Methods: We enrolled 24 patients treated with RT for various primary brain tumors, who showed newly appearing enhancing lesions more than one year after completion of RT on follow-up MRI. The enhancing-lesions were confirmed as recurrences (n=14) or RT-changes (n=10). We calculated the mean values of normalized cerebral blood volume (nCBV), apparent diffusion coefficient (ADC), and proportion of dark signal intensity on SWI (proSWI) for the enhancing-lesions. All the values between the two groups were compared using t-test. A multivariable logistic regression model was used to determine the best predictor of differential diagnosis. The cutoff value of the best predictor obtained from receiver-operating characteristic curve analysis was applied to calculate the sensitivity, specificity, and accuracy for the diagnosis. Results: The mean nCBV value was significantly higher in the recurrence group than in the RT-change group (P=.004), and the mean proSWI was significantly lower in the recurrence group (P<.001). However, no significant difference was observed in the mean ADC values between the two groups. A multivariable logistic regression analysis showed that proSWI was the only independent variable for the differentiation; the sensitivity, specificity, and accuracy were 78.6% (11 of 14), 100% (10 of 10), and 87.5% (21 of 24), respectively. Conclusion: The proSWI was the most promising parameter for the differentiation of newly developed enhancing-lesions more than one year after RT completion in brain tumor patients.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.4
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• pp.64-73
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• 2008

The cDNA of CCF (coelomic cytolytic factor)-like gene (EC 3.2.1.16), a kind of glycosyl hydorlase, was isolated and cloned from the midgut of the earthworm Eisenia anderi. The size of nucleotide sequence appeared to be 1,152 bp and its predicted coding region was composed of 384 amino acid residues including the initiation methionine. The 17 residues at N-terminal end in the deduced amino acid sequence were regarded to be a signal peptide. Based on the amino acid sequence analysis, it appeared that this CCF-like protein could belong to glycosyl hydrolase family 16 (GHF16) and showed a high sequence homology of about 79~99% with CCF and CCF-like proteins from other earthworm species. The CCFs and CCF-like proteins from various earthworm species exhibited a 100% homology in the polysacchride-binding motif and glucanase motif. It has been reported that the CCFs isolated from E. fedita appeared to show a broader pattern recognition specificity than those from other earthworm species because this species resides in decaying organic matter showing very high microbial activity, implying that CCF-like protein isolated in this study from E. andrei might exhibit a broad substrate specificity that is a useful characteristic for industrial application. A phylogenetic analysis using the deduced amino acid sequences of CCF-related proteins through the BLASTX revealed that GHF16 families could be divided into three groups of metazoa, viriplantae and eubacteria subfamily. Subsequently the CCF-related proteins of metazoa subfamily could clearly be subgroup into lophotrochozoan and edysozoan type including a deuterostome origin. Further understanding of the biological properties of E. andrei CCF-like protein should be addressed to regulate the ${\beta}$-D-glucan hydrolysis and production for the industrial uses.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1105-1112
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• 1997

By sequential degradation using partial acid hydrolysis of a weakly acidic polysaccharide (GL-4IIb2'), two acidic oligosaccharide fragments, PA-2' and PA-1-III were isolated and their structures were characterized. PA-2' consisted of almost equal proportion of a rhamnose (Rha) and an unusual sugar, 3-deoxy-D-manno-2-octurosonic acid (Kdo). When permethylated oligosaccharide-alditol derived from PA-2' was analyzed by GC-MS, the peak gave the fragment ions at m/z 189 $(bA_1,\;6-deoxyhexose)$ and at m/z 308 $(aJ_2,\;alditol\;from\;Kdo)$. The peak also gave the characteristic ion at m/z 162 but it did not give the fragment ion at m/z 177, suggesting that Kdo is substituted at C5 but not at C4. Methylation analysis also indicated that PA-2' was composed mainly of terminal Rhap and 5-substituted Kdo. When the reduced product from PA-2' was analyzed by $^1H-NMR$, it gave a signal at 5.09 ppm due to an anomeric proton of ${\alpha}-L-Rha$. These results indicated that PA-2' mainly contained ${\alpha}-L-Rhap-(1{\rightarrow}5)-Kdo$. On the other hand, PA-1-III mainly comprised Rha and Kdo in addition to small proportions of arabinose (Ara) and 3-deoxy-D-lyxo-2-heptulosaric acid (Dha). MS analysis of permethylated oligosaccharide-alditols from PA-1-III suggested that the major peak 1P was $Rhap-(1{\rightarrow}5)-Kdo$ whereas the minor peaks 2P and 3P possessed $Araf-(1{\rightarrow}5)-Dha$ unit and these peaks were produced as epimers during reduction of carbonyl groups in Dha.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.1
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• pp.41-50
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• 2022

In this paper, a method to directly calculate the major elements of skin color such as melanin and hemoglobin from the RGB signal of the camera is proposed. The main elements of skin color typically measure spectral reflectance using specific equipment, and reconfigure the values at some wavelengths of the measured light. The values calculated by this method include such things as melanin index and erythema index, and require special equipment such as a spectral reflectance measuring device or a multi-spectral camera. It is difficult to find a direct calculation method for such component elements from a general digital camera, and a method of indirectly calculating the concentration of melanin and hemoglobin using independent component analysis has been proposed. This method targets a region of a certain RGB image, extracts characteristic vectors of melanin and hemoglobin, and calculates the concentration in a manner similar to that of Principal Component Analysis. The disadvantage of this method is that it is difficult to directly calculate the pixel unit because a group of pixels in a certain area is used as an input, and since the extracted feature vector is implemented by an optimization method, it tends to be calculated with a different value each time it is executed. The final calculation is determined in the form of an image representing the components of melanin and hemoglobin by converting it back to the RGB coordinate system without using the feature vector itself. In order to improve the disadvantages of this method, the proposed method is to calculate the component values of melanin and hemoglobin in a feature space rather than an RGB coordinate system using a feature vector, and calculate the spectral reflectance corresponding to the skin color using a general digital camera. Methods and methods of calculating detailed components constituting skin pigments such as melanin, oxidized hemoglobin, deoxidized hemoglobin, and carotenoid using spectral reflectance. The proposed method does not require special equipment such as a spectral reflectance measuring device or a multi-spectral camera, and unlike the existing method, direct calculation of the pixel unit is possible, and the same characteristics can be obtained even in repeated execution. The standard diviation of density for melanin and hemoglobin of proposed method was 15% compared to conventional and therefore gives 6 times stable.

• Journal of the Korean Chemical Society
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• v.39 no.3
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• pp.163-175
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• 1995

Metal free phthalocyanine($H_2Pc$) partially doped with iodine, $H_2Pc(I)x$, has been made to improve photosensitizing efficiency of ZnO/$H_2Pc$. The content of iodine dopant level(x) for $H_2Pc(I)x$ upon $H_2Pc$ polymorphs was characterized as ${\chi}-H_2Pc(I)_{0.92}$ and ${\beta}-H_2Pc(I)_{0.96}$ by elemental analysis. Characterization of iodine-oxidized $H_2Pc$ were investigated by TGA (thermogravimetric analysis), UV-Vis, FT-IR, Raman and ESR (electron spin resonance) spectrum, and the adsorption properties of $H_2Pc(I)x$ on ZnO were characterized by means of Raman and ESR studies. TGA for $H_2Pc(I)x$ showed a complete loss of iodine at approximately 265$^{\circ}C$ and the Raman spectrum of $H_2Pc(I)x$ and ZnO/$H_2Pc(I)x$ at 514.5 nm showed characteristic $I_3^-$ patterns in the frequency region 90∼550 $cm^{-1}$. ZnO/$H_2Pc(I)x$ exhibited a very intense and narrow ESR signal at $g=2.0025{\pm}0.0005$ compared to $H_2Pc$/ZnO. Iodine doped ZnO/$H_2Pc(I)x$ showed a better photosensitivity compared to iodine undoped ZnO/$H_2Pc$. That is, the surface photovoltage of ${\chi}-H_2Pc(I)_{0.92}$/ZnO was approximately 31 times greater than that of ZnO/${\chi}-H_2Pc$ and ZnO/${\beta}-H_2Pc(I)_{0.96}$ was 5 times more efficient than ZnO/${\beta}-H_2Pc$ at 670 nm. And the dependence of photosensitizing effect upon $H_2Pc$ polymorphs was exhibited that the surface photovoltage of ZnO/${\chi}-H_2Pc(I)_{0.92}$ was approximately 5 times greater than ZnO/${\beta}-H_2Pc(I)_{0.96}$ at 670 nm. Therefore Iodine doping of H_2Pc$ resulted in increase in photoconductivity of $H_2Pc$ and photovoltaic effect of ZnO/$H_2Pc$ in the visible region.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.3
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• pp.3-9
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• 2017

Recently, in 3rd Generation Partnership Project(3GPP), there is a study of the Long Term Evolution(LTE) based vehicle communication which has been actively conducted to provide a transport efficiency, telematics and infortainment. Because the vehicle communication is closely related to the safety, it requires a reliable communication. Because vehicle speed is very fast, unlike the movement of the user, radio channel is rapidly changed and generate a number of problems such as transmission quality degradation. Therefore, we have to continuously updates the channel estimates. There are five types of conventional channel estimation scheme. Least Square(LS) is obtained by pilot symbol which is known to transmitter and receiver. Decision Directed Channel Estimation(DDCE) scheme uses the data signal for channel estimation. Constructed Data Pilot(CDP) scheme uses the correlation characteristic between adjacent two data symbols. Spectral Temporal Averaging(STA) scheme uses the frequency-time domain average of the channel. Smoothing scheme reduces the peak error value of data decision. In this paper, we propose the novel channel estimation scheme in LTE based Vehicle-to-Vehicle(V2V) environment. In our Hybrid Reliable Channel Estimation(HRCE) scheme, DDCE and Smoothing schemes are combined and finally the Linear Minimum Mean Square Error(LMMSE) scheme is applied to minimize the channel estimation error. Therefore it is possible to detect the reliable data. In simulation results, overall performance can be improved in terms of Normalized Mean Square Error(NMSE) and Bit Error Rate(BER).

• Clinical and Experimental Pediatrics
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• v.45 no.11
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• pp.1373-1380
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• 2002

Purpose : Acute measles encephalitis(ME) is characterized by an abrupt onset of fever and obtundation, frequently accompanied by seizures and multifocal neurological signs. The aim of this study was to clarify the clinical manifestation, progression and the brain SPECT patterns in patients with acute ME. Methods : This study included 11 children with acute ME admitted to Chonbuk National University Hospital. Ten patients received a first dose of measles vaccine, one patient did not receive a first dose, and no patients received a second dose. ME was diagnosed based on characteristic clinical pictures, measles antibodies by ELISA and abnormal CSF findings. Brain MRI and brain SPECT were performed in 11 patients with acute ME. Results : There were four males and seven females whose ages at onset ranged between 18 months and 14 years(mean : 10.5 years). The main clinical neurologic pictures were loss of consciousness( 10) and seizure(five). The titer of IgG and IgM antimeasles antibodies in serum were positive in 10 patients. In CSF, nine patients had IgG antibodies and one patient had IgM antibodies. The concentration of protein(mean : $124{\pm}60mg/dL$) and WBC counts(mean : $158{\pm}157/{\mu}L$) in CSF were elevated in all patients. In electroencephalographic examination, nine patients showed increased slow waves. Seven of 11 patients(63.6%) revealed high signal intensity on the brain MRI. In contrast, all patients showed hypoperfusion in brain SPECT examination. According to brain SPECT, the perfusion deficits were frequently observed in the frontal lobe(nine), temporal (nine), parietal(eight) and thalamus(eight). Conclusion : Brain SPECT is more sensitive than MRI for the evaluation of brain damage in early stages of acute ME.