• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.1
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• pp.11-17
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• 2013

Purpose: The use of SUV which should be normalized by lean body mass (LBM) is recommended for PET response criteria in solid tumors. LBM which was determined by whole body CT was used for SUV normalization (SUL) in this study. The purpose of the present study was to assess interobserver and intraobserver reproducibility of SUL measurements in reference organs. Materials and Methods: F-18 FDG PET/CT was conducted on 52 subjects and LBMs were directly determine by whole body CT for normalization of SUV. The 3 cm diameter spherical VOI, $1\times2$ cm cylindrical VOI, 2 cm diameter spherical VOI were placed in the liver, descending aorta and spleen, respectively. Experienced two observers measured SULmax and SULmean in each organ. Repeated measurements were conducted two weeks apart by observer 1 blind to previous results. Similarly, measurements were conducted on the same patients by observer 2. For assessing reproducibility(or repeatability), the paired t-test, Pearson's correlation coefficients (CC), and technical error of measurement (TEM) were calculated. Results: For interobserver reproducibility in liver SULmax and SULmean, no significant differences were found between observers(paired t-test, P=0.536, 0.293, respectively). CC and TEM for liver SULmean were 0.909 (P=0.000) and 0.067 SUL unit, respectively. Corresponding figures for liver SULmax were 0.882 (P=0.000) and 0.117 SUL unit, respectively. For intraobserver reproducibility in liver SULmax and SULmean, no significant differences were observed within observer1 (paired t-test, P=0.374, 0.268, respectively). CC and TEM for liver SULmean were 0.924 (P=0.000) and 0.061 SUL, respectively. Corresponding figures for liver SULmax were 0.908 (P=0.000) and 0.104 SUL, respectively. Similarly, no significant differences were found in SULmax and SULmean of the spleen and aorta between observers. Conclusion: The current study demonstrated that both SULmean and SULmax measurements in normal reference organs are highly reproducible. Reproducibility of SULmean in reference organs were slightly better than SULmax. Interobsever technical error of measurement was less than 0.10 SUL unit for liver SULmean, and 0.12 SUL unit for liver SULmax. Intraobsever technical error of measurement was less than 0.07 SUL unit for liver SULmean, and 0.11 SUL unit for liver SULmax.

• Investigative Magnetic Resonance Imaging
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• v.18 no.4
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• pp.303-313
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• 2014

Purpose : In-vivo conductivity reconstruction using transmit field ($B_1{^+}$) information of MRI was proposed. We assessed the accuracy of conductivity reconstruction in the presence of statistical noise in complex $B_1{^+}$ map and provided a parametric model of the conductivity-to-noise ratio value. Materials and Methods: The $B_1{^+}$ distribution was simulated for a cylindrical phantom model. By adding complex Gaussian noise to the simulated $B_1{^+}$ map, quantitative conductivity estimation error was evaluated. The quantitative evaluation process was repeated over several different parameters such as Larmor frequency, object radius and SNR of $B_1{^+}$ map. A parametric model for the conductivity-to-noise ratio was developed according to these various parameters. Results: According to the simulation results, conductivity estimation is more sensitive to statistical noise in $B_1{^+}$ phase than to noise in $B_1{^+}$ magnitude. The conductivity estimate of the object of interest does not depend on the external object surrounding it. The conductivity-to-noise ratio is proportional to the signal-to-noise ratio of the $B_1{^+}$ map, Larmor frequency, the conductivity value itself and the number of averaged pixels. To estimate accurate conductivity value of the targeted tissue, SNR of $B_1{^+}$ map and adequate filtering size have to be taken into account for conductivity reconstruction process. In addition, the simulation result was verified at 3T conventional MRI scanner. Conclusion: Through all these relationships, quantitative conductivity estimation error due to statistical noise in $B_1{^+}$ map is modeled. By using this model, further issues regarding filtering and reconstruction algorithms can be investigated for MREPT.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.26 no.4
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• pp.283-304
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• 2015

The purpose of this study was to identify Web accessibility issues of healthcare websites of the Korean government and public agencies by evaluating these websites' accessibility in accordance with the Korean Web Contents Accessibility Guideline. This study conducted both automated and expert testing to assess the accessibility of a total of 27 health-related websites. The results of the assessment which was conducted in two stages indicated that institutions such as the National Hospital and National Rehabilitation Center demonstrated almost no Web accessibility error. In addition, the Korea Health Insurance Review and Assessment Service, the Ministry of Health and Welfare, the Health Services Agency, the Ministry of Food and Drug Safety, and the Korea Medical Dispute Mediation and Arbitration Agency attained very high web accessibility. However, the results of an expert evaluation highlighted that there were considerable errors in providing appropriate alternative text, which was not found in the automated test, and the color contrast of the text content did not comply with Web accessibility standard. Therefore, these websites did not support web accessibility for the sight-impaired. Furthermore, the present study found that it was difficult to deliver accurate information to users due to errors in the default language display and markup, and also, issues of skipping repeated content, content linearization, and compliance with keyboard use were considered as challenges that might arise for people with sight, cognitive and mobility impairments with respect to Web accessibility. It is the first study that evaluated accessibility of healthcare websites of the Korean government and public agencies based on the Korean Web Contents Accessibility Guideline. The present study made a contribution to research on Web accessibility by conducting expert testing, which provided a more complete assessment that identified the degree and specific issues of accessibility errors when compared to automated testing.

• Journal of Sasang Constitutional Medicine
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• v.9 no.2
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• pp.203-225
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• 1997

Jihwangbakhotang(地黃白虎楊) is made by Li Je Ma, the creator of the Four Constitutional Medicine. Single and 13 weeks oral repeated dose toxicity studies were conducted in Sprague Dawley rats of both sexes to elucidate the potential acute and subchronic toxicity of JBT extract and reversibility of any effects. In the single dose study, JBT extract was administered orally to rats with the dose of 2 g/kg and 8 g/kg. In the long term administration of 13 weeks, the JBT extract of 125 mg/kg/day, 500 mg/kg/day, 2000 mg/kg/day was administered to rats. The change of blood weight, urine volume, electrolyte in urine, hematological change, the change of blood chemistry, autopsy finding, and histological observation were researched, the results were as follows; 1. The lethal dose of JBT extract seems to be over 10 g/kg, the single administration of JBT extract 8 g/kg showed no toxical signs except little increase of urine volume. 2. The change of body weight had the trend of decrease in the group of, but has no significance, and also the consumption of food and water had no changes. 3. The hematological changes induced by the 13 weeks administration of JBT extract showed the significance in the item of Hb, MCH, MCV, WBC in the group of 125 mg/kg/day. 4. In the test of blood chemistry, total cholesterol showed little decrease and A/G ratio showed little increase, but the change was not clear, and the standard error was large. So the result was obtained insignificantly and the toxicity of JBT extract was not observed. 5. In the male group after recovery period, the level of cholesterol and triglyceride decreased slightly, but the result was not significant. 6. In the urine test, the little change of electrolyte was appeared, but it seemed not to be the result induced by the toxicity of JBT extract. 7. In each group of male and female rats, the weight change of organ and the serum histological changes was observed, but the result did not showed the dose dependent toxicity. So the toxicity of JBT extract was not regarded. In the conclusion, the toxicity of JBT extract was not observed in the single dose treatment and long term repetitive administration of JBT extract.

• The Journal of Engineering Geology
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• v.29 no.4
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• pp.565-578
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• 2019

Basic friction angles of Hwangdeung granite, Berea sandstone, Jeongsun marble, Hongcheon gneiss, Pungam shale and Eumseong sandy shale were measured by direct shear test, tilt test and pull test. Characteristics of basic friction angle and the accuracy of test methods were compared and the optimal method in measuring basic friction angle was suggested. Although basic friction angles might be measured accurately by direct shear test, the test apparatus is expensive and procedures are complicated. Tilt tests which is the suggested method for measuring basic friction angle by International Association for Rock Mechanics also provided similar basic friction angles measured by direct shear test. However, the error measured for the same rock type is higher than 7° and values by repeated measurements in one sample show different trends, such as increasing or decreasing or almost constant as measurements continued. The difference measured in one gneiss sample is higher 12°, indicating that tilt test may be not a reliable method for measuring basic friction angle. Not only pull test provided accurate and consistent results under low normal stresses, but also test apparatus is simple and inexpensive and procedure is not complicated, indicating that pull test may be the optimal method for measuring basic friction angle.

• Journal of Biosystems Engineering
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• v.36 no.2
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• pp.130-139
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• 2011

Three modes of VIS/NIR spectroscopic measurement (interactance and two modes of transmission) were compared for their ability to estimate soluble solids content (SSC) of 'Shingo' pear non-destructively. The two transmission modes are named as full- and semi-transmission, where full-transmission stands for passing of light through abdomen of pear and semi-transmission is for transit of light mainly through flesh of pear. For comparison of the modes, prediction models developed from the collected spectroscopic data by the three modes were developed and tested for comparison of their performance. Partial least square regression (PSLR) was used to develop the models and various pre-processing methods were applied to develop models of high accuracy. The experiment was repeated three times with pears produced in different regions. The experiments resulted that selection of pre-processing is very important to attain accurate models, and multiplicative scatter correction (MSC) was selected as a pre-processor of high accuracy for the three modes of spectroscopic measurement in every experiment. Except for MSC, different group of pre-processing methods were selected for the three modes of measurement in every experiment without any tendency to the tested modes of measurement and pears of different produced region. Root-mean-square error of prediction (RMSEP) of prediction models of the three modes of measurement using prepreocessor of MSC were compared for their ability to estimate SSC. The models resulted in ranges of $0.37{\sim}0.57^{\circ}Brix$, $0.65{\sim}0.72^{\circ}Brix$, $0.39{\sim}0.51^{\circ}Brix$ for interactance, full- and semi-transmission, respectively. As shown, modes of semi-transmission and interactance resulted about the same level of prediction accuracy and were noted as modes of high performance to predict SSC.

• Journal of Preventive Medicine and Public Health
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• v.37 no.2
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• pp.111-119
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• 2004

Purpose : To identify those factors influencing the post-operative satisfaction in myopia patients receiving laser in situ keratomileusis (LASIK) Methods : This study included 288 consecutive patients who received LASIK between July and December 2001 from two eye clinics located in Seoul and Pusan. Factors that were considered to influence post-operative satisfaction included pre-operative baseline characteristics, pre-operative expectation for treatment outcomes, and treatment outcomes. Before undergoing LASIK, study subjects were asked to rate the degree of their expectation for the improvement of visual functions and symptoms after LASIK on a 5-point Likert-type scale: where 1 referred to 'somewhat worse,' 2 to 'no change,' 3 to 'somewhat improved,' 4 to 'improved,' and 5 to 'very improved.' Self-administered questionnaire was used to evaluate baseline visual functions and symptoms on a 5-point scale before LASIK. At 6 months after LASIK, the evaluation was repeated to measure treatment outcomes in terms of the difference in the score before and after LASIK. Post-operative satisfaction was also measured at 6 months on a 5-point scale. Multiple regression analysis was performed to examine the independent relationship between influencing factors and postoperative satisfaction. Results : A total of 171 patients (59.4%) participated in the 6-month follow-up investigation. The average expectation scores for the improvement in visual functions and symptoms were 3.8 and 3.4, respectively. The average score for the 7 questions assessing satisfaction was 4.0. The results of the regression analysis showed that the post-operative satisfaction increased with improvement in the visual function ($\beta$=0.16, p<0.05) and symptoms ($\beta$=0.25, p<0.05), the degree of preoperative refractive error ($\beta$ =0.26-0.67, p<0.05) and in male patients ($\beta$=0.31, p<0.1). The pre-operative expectation was not a statistically significant factor in explaining postoperative satisfaction in the regression model. Conclusion : The finding from this study was that patients with very severe myopia tended to be more satisfied with the treatment than those with mild myopia, which implies that LASIK can be more beneficial to those suffering from a severe visual condition. Patient satisfaction was also significantly affected by the treatment outcomes experienced after LASIK. This suggests that improving the clinical outcome is the most fundamental requirement for the improvement of patient satisfaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.870-877
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• 2020

A suction bucket foundation, especially useful at depths of more than 20m, is a method of construction. The method first places an empty upturned bucket at the target site. Then, the bucket is installed by sucking water or air into it to create negative pressure. For stability, it is crucial to secure the verticality of the bucket. However, inclination by the bucket may occur due to sea-bottom conditions. In general, a repeated intrusion-pulling method is used for securing verticality. However, it takes a long time to complete the job. In this paper, we propose a real-time suction bucket verticality monitoring system. Specifically, the system consists of a sensor unit that collects raw verticality data, a controller that processes the data and wirelessly transmits the information, and a display unit that shows verticality information of a circular steel pipe. The system is implemented using an inclination sensor and an embedded controller. Experimental results show that the proposed system can efficiently measure roll/pitch information with a 0.028% margin of error. Furthermore, we show that the system properly operates in a suction bucket-based model experiment.

• Journal of Bio-Environment Control
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• v.13 no.4
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• pp.209-216
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• 2004

This study was aimed to assess the effects of microclimate factors on lettuce chlorophyll fluorescent responses and to develop an environment control system for plant growth by adopting a simple genetic algorithm. The photosynthetic responses measurements were repeated by changing one factor among six climatic factors at a time. The maximum Fv'/Fm' resulted when the ambient temperature was $21^{\circ}C,\;CO_2$ concentration range of 1,200 to 1,400 ppm, relative humidity of $68\%$, air current speed of $1.4m{\cdot}s^{-1}$, and the temperature of nutrient solution of $20^{\circ}C$. In PPF greater than $140{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, Fv'/Fm' values were decreased. To estimate the effects of combined microclimate factors on plant growth, a photosynthesis efficiency model was developed using principle component analysis for six microclimate factors. Predicted Fv'/Fm' values showed a good agreement to measured ones with an average error of $2.5\%$. In this study, a simple genetic algorithm was applied to the photosynthesis efficiency model for optimal environmental condition for lettuce growth. Air emperature of $22^{\circ}C$, root zone temperature of $19^{\circ}C,\;CO_2$ concentration of 1,400 ppm, air current speed of $1.0m{\cdot}s^{-1}$, PPF of $430{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, and relative humidity of $65\%$ were obtained. It is feasible to control plant environment optimally in response to microclimate changes by using photosynthesis efficiency model combined with genetic algorithm.

• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.504-511
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• 2016

Lactulose, a synthetic disaccharide, has received increasing interest because of its role as a prebiotic that can increase the proliferation of Bifidobacterium and Lactobacillus spp. and enhance the absorption of calcium and magnesium. While the industrial production of lactulose is still mainly achieved by the chemical isomerization of lactose in alkaline media, this process has drawbacks including the need to remove catalysts and by-products, as well as high energy requirements. Recently, the use of cellobiose 2-epimerase (CE) has been considered an interesting alternative for industrial lactulose production. In this study, to develop a process for enzymatic lactulose production using CE, we screened improved mutant enzymes ($CS-H^RC^E$) from a library generated by an error-prone PCR technique. The thermostability of one mutant was enhanced, conferring stability up to $75^{\circ}C$, and its lactulose conversion yield was increased by 1.3-fold compared with that of wild-type CE. Using a recombinant Escherichia coli strain harboring a CS35 $H^RC^E$-expressing plasmid, we prepared cell beads immobilized on a Ca-alginate substrate and optimized their reaction conditions. In a batch reaction with 200 g/l lactose solution and the immobilized cell beads, lactose was converted into lactulose with a conversion yield of 43% in 2 h. In a repeated 38-plex batch reaction, the immobilized cell beads were relatively stable, and 80% of the original enzyme activity was retained after 4 cycles. In conclusion, we developed a reasonable method for lactulose production by immobilizing cells expressing thermostable CE. Further development is required to apply this approach at an industrial scale.