• Progress in Medical Physics
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• v.26 no.1
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• pp.28-35
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• 2015

In this study, we investigated the effects of an iterative reconstruction algorithm and an automatic exposure control (AEC) technique on image quality and radiation dose through phantom experiments with coronary computed tomography (CT) angiography protocols. We scanned the AAPM CT performance phantom using 320 multi-detector-row CT. At the tube voltages of 80, 100, and 120 kVp, the scanning was repeated with two settings of the AEC technique, i.e., with the target standard deviations (SD) values of 33 (the higher tube current) and 44 (the lower tube current). The scanned projection data were reconstructed also in two ways, with the filtered back projection (FBP) and with the iterative reconstruction technique (AIDR-3D). The image quality was evaluated quantitatively with the noise standard deviation, modulation transfer function, and the contrast to noise ratio (CNR). More specifically, we analyzed the influences of selection of a tube voltage and a reconstruction algorithm on tube current modulation and consequently on radiation dose. Reduction of image noise by the iterative reconstruction algorithm compared with the FBP was revealed eminently, especially with the lower tube current protocols, i.e., it was decreased by 46% and 38%, when the AEC was established with the lower dose (the target SD=44) and the higher dose (the target SD=33), respectively. As a side effect of iterative reconstruction, the spatial resolution was decreased by a degree that could not mar the remarkable gains in terms of noise reduction. Consequently, if coronary CT angiogprahy is scanned and reconstructed using both the automatic exposure control and iterative reconstruction techniques, it is anticipated that, in comparison with a conventional acquisition method, image noise can be reduced significantly with slight decrease in spatial resolution, implying clinical advantages of radiation dose reduction, still being faithful to the ALARA principle.

• Korean Journal of Heritage: History & Science
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• v.53 no.1
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• pp.24-33
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• 2020

In excavated bronze artifacts, corrosion products of various shapes and colors are observed due to multiple corrosion factors coexisting in the burial environment, and these corrosion products can constitute important data not only in terms of long-term corrosion-related information, but also in connection with preservation of artifacts. As such, scientific analysis is being carried out on the corrosion layer and corrosion products of bronze artifacts, and the corrosion mechanism and the characteristics of corrosion products elucidated, which is essential for interpreting the exposed burial environment and its association with corrosion factors inside the burial environment. In this study, after classifying excavated bronze artifacts according to alloy ratio and fabrication technique, comprehensive analysis of the surface of corrosion artifacts, corrosion layer, and corrosion products was carried out to investigate the corrosion mechanism, formation process of the corrosion layer, and characteristics of corrosion products. The study designated two groups according to alloy ratio and fabrication technique. In Group 1, which involved a Cu-Sn-Pb alloy and had no heat treatment, the surface was rough and external corrosion layers were formed on a part, or both sides, of the inside and the outside, and the surface was observed as being green or blue. α+δ phase selection corrosion was found in the metal and some were found to be concentrated in an empty space with a purity of 95 percent or more after α+δ phase corrosion. The Cu-Sn alloy and heat-treated Group 2 formed a smooth surface with no external corrosion layer, and a dark yellow surface was observed. In addition, no external corrosion layer was observed, unlike Group 1, and α corrosion was found inside the metal. In conclusion, it can be seen that the bronze artifacts excavated from the same site differ in various aspects, including the formation of the corrosion layer, the shape and color of the corrosion products, and the metal ion migration path, depending on the alloy ratio and fabrication technique. They also exhibited different corrosion characteristics in the same material, which means that different forms of corrosion can occur depending on the exposure environment in the burial setting. Therefore, even bronze artifacts excavated from the same site will have different corrosion characteristics depending on alloy ratio, fabrication technique, and exposure environment. The study shows one aspect of corrosion characteristics in specific areas and objects; further study of corrosion mechanisms in accordance with burial conditions will be required through analysis of the corrosive layer and corrosive product characteristics of bronze artifacts from various regions.

• The KIPS Transactions:PartB
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• v.19B no.2
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• pp.123-126
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• 2012

This paper proposed a method to separate a liver into left and right liver lobes for simple and exact volumetry of the river graft at abdominal MDCT(Multi-Detector Computed Tomography) image before the living donor liver transplantation. A medical team can evaluate an accurate river graft with minimized interaction between the team and a system using this algorithm for ensuring donor's and recipient's safe. On the image of segmented liver, 2 points(PMHV: a point in Middle Hepatic Vein and PPV: a point at the beginning of right branch of Portal Vein) are selected to separate a liver into left and right liver lobes. Middle hepatic vein is automatically segmented using PMHV, and the cutting line is decided on the basis of segmented Middle Hepatic Vein. A liver is separated on connecting the cutting line and PPV. The volume and ratio of the river graft are estimated. The volume estimated using 2 points are compared with a manual volume that diagnostic radiologist processed and estimated and the weight measured during surgery to support proof of exact volume. The mean ${\pm}$ standard deviation of the differences between the actual weights and the estimated volumes was $162.38cm^3{\pm}124.39$ in the case of manual segmentation and $107.69cm^3{\pm}97.24$ in the case of 2 points method. The correlation coefficient between the actual weight and the manually estimated volume is 0.79, and the correlation coefficient between the actual weight and the volume estimated using 2 points is 0.87. After selection the 2 points, the time involved in separation a liver into left and right river lobe and volumetry of them is measured for confirmation that the algorithm can be used on real time during surgery. The mean ${\pm}$ standard deviation of the process time is $57.28sec{\pm}32.81$ per 1 data set ($149.17pages{\pm}55.92$).

• Archives of design research
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• v.13 no.1
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• pp.209-218
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• 2000

The purpose of this study was to improve the curriculum for industrial design department in the junior colleges. In order to achieve the purpose, two methodologies were carried out. First is job analysis of the industrial designers who have worked in the small & medium manufacturing companies, second is survey for the opinions of professors in the junior colleges. Some results were as follows: 1. The period of junior college for industrial designers is 2 years according to present. But selectively 1 year of advanced course can be established. 2. The practice subjects same as computational formative techniques needed to product development have to be increased. In addition kinds of selection subjects same as foreign language, manufacturing process, new product information and consumer behavior investigation have to be extended. 3. The next subjects need to adjust the title, contents and hours. (1) The need of 3.D related subjects same as computer modeling, computer rendering, 3.D modeling was high. The use of computer is required to design presentation subjects. (2)The need of advertising and sale related subjects same as printing, merchandise, package, typography, photography was low, the need of presentation techniques of new product development was high. (3) The need of field practice, special lecture on practice and reading original texts related subjects was same as at present, but these are not attached importance to form. As the designers feel keenly the necessity of using foreign language, the need of language subject was high.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.78
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• pp.93-117
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• 2018

In all countries of the world, the development of trade is an important factor for the survival of the national economy. Increased export will lead to national economic growth. Export is directly linked to employment, and the industrial structure will be developed in the direction to produce products of comparative advantages. Therefore, every country around the world is trying to promote export regardless of the size of its economy. Accordingly, this paper focused on the promotion of export of domestic companies. It proposed to cultivate trade experts to promote export of domestic companies. The following five methods were proposed to materialize the proposal. First, it is important to foster trade experts to expand and foster the one-person creative companies. In particular, it is important to develop a professional education curriculum. It is necessary to design and conduct a systematic curriculum throughout the process including follow-up after education such as teaching detailed procedures for establishing a trade business, identification of relevant regulations and related organizations, understanding of special features of each exporting country, and details of exporting procedures through specialist training for the individual industries, helping themto keep their network steady so that they can easily get help from consultants. Second, it is necessary to educate traders working in the field to make them trade experts and utilize themin on-the-job training and consulting. To do this, it is necessary to introduce systematic consultant selection process, and to introduce a systemto educate and manage them. It is because, we must select the most appropriate candidates, educate themto be lecturers and consultants, and dispatch themto the field, in order to make the best achievement in export. Nurturing trading professionals utilizing the current trading workers to activate export of domestic companies can be more efficient through cooperation of trading education agencies and related agencies in various industries. Third, it is also proposed to cultivate female trade experts by educating female trade workers whose career has been disrupted. It is to provide career disrupted women with opportunities to work after training them as trade professionals and to give manpower pool to domestic companies that are preparing for export. Fourth, it is also proposed to educate foreign students living in Korea to be trading experts and to utilize them as trading infra. They can be trading professionals who will contribute to the promotion of export. In the short term, they will be provided with opportunities for employment and start-upin the field of trade, and in the mid- to long-term, they may develop a business network between Korea and their own countries. To this end, we need to improve the visa system, expand free trade education opportunities, and support them so that they can establish small but strong enterprises. Fifth, it is proposed to proactively expand trade education to specialized high school students. Considering that most of domestic companies pursuing activation of export are small but strong companies or small and mediumsized companies, they may prefer high school graduates rather than university graduates because of financial limitations. Besides, the specialized high school students may occupy better position in the job market if they are equipped with expertise in trading. This study can be meaningful, in that it is the first research that focuses on cultivating trading experts to contribute to the export activation of domestic companies. However, it also has a limitation that it has failed to reflect the more specific field voices. It is hoped that detailed plans will be derived from the opinions of the employees of domestic companies making efforts to become an export company in the related researches in the future.

• Pediatric Infection and Vaccine
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• v.7 no.2
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• pp.193-200
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• 2000

Purpose : This study was designed and performed for evaluations of clinical manifestation and course of the children under 2 year of age with respiratory tract infection and positive respiratory syncytial virus(RSV) antigen. Methods : The selection criteria of the patients were children under 24 month-of-age, Clinical manifestation of respiratory tract infection, and positive RSV antigen that was detected by Vitek ImmunoDiagnostic Assay System(VIDAS) from nasal cavity. The additional laboratory and simple chest X-ray findings were reviewed from the chart of children who were admitted Wonkwang university hospital from October 1999 to March 2000. Results : Total number of patients enrolled on this study was 102. The 48(47%) children were RSV antigen positive by VIDAS method. Abnormal chest X-ray findings were noticed in 38 cases. The male to female sex ratio of 48 RSV antigen positive cases was 1.2 : 1. The mean and range of age was $10.2{\pm}5.9$ and 1.0~24 months. The peak outbreak of cases was noticed on November, 1999. All of the cases shows coughing but rale was audible in 30 cases(60%). Dyspnea, wheezing, and intercostal retraction were noticed 11(23%), 15(31%), and 10(21%) cases respectively. The most common chest X-ray finding was scattered patch infiltration that was noticed in 30 cases(63%). The mean total white blood cell counts in peripheral blood was $12,608{\pm}4,686/mm^3$. The mean blood level of IgA and IgE were $50.8{\pm}20.9$ and $72.1{\pm}98.3mg/dL$ respectively. The C-reactive protein was $16.0{\pm}18.5mg/L$. Total 5 cases need a mechanical respiraton. The duration of admission was under 7 days in 36 cases(75%). Conclusion : The RSV antigen was detected commonly in late fall and winter season. The severity of children under 2 years old with RSV respiratory tract infection take in some degree a gave courses.

• Pediatric Infection and Vaccine
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• v.11 no.1
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• pp.73-80
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• 2004

Purpose : The serial clinical findings, biochemical results, and serological hepatitis B virus(HBV) markers in Korean children with chronic HBV infection were analyzed to determine the relationships among these factors. Methods : Ninety children have been chosen from those who have visited to the Department of Pediatrics at St. Vincent's Hospital in The Catholic University of Korea from July 1st, 1995 to June 30th, 2000. The sample patients were followed up for over six months. HBV markers and liver function tests were all performed. Results : All children were asymptomatic at presentation. Eighty-three percent of the children had a history of chronic HBV infection in their families. Eighty-one percent were HBeAg positive, 16% were anti-HBe positive, while 3% were all HBeAg and anti-HBe negative. The prevalence of HBeAg among three age groups : 0~5; 6~10; and 11~15 year-old was 90%, 96% and 61% respectively. The prevalence of HBeAg in less than 10 year-old group was significantly higher than 11~15 year-old group(P=0.001). Serum ALT levels were within 40 IU/L in 64% children, 41~80 IU/L in 17%, 81~200 IU/L in 10%, and beyond 201 IU/L in 9%. The percentage of abnormality of ALT levels in HBeAg positive patients was significantly higher than that of HBeAg negative(P=0.036). Eleven of the 73 HBeAg positive children lost their HBeAg and seroconverted to anti-HBe. In these cases, all had transient elevations in ALT levels before HBeAg seroconversions. The annual rates of spontaneous seroconversion of HBeAg and HBsAg were 9.7% and 0.6%, respectively. Conclusion : Recognition of the dynamics of these changes in viral markers and biochemical findings is needed in the selection and evaluation of therapeutic regimens, establishment of treatment, and calling for controlled trials with adequate follow-up. The hepatitis B carrier state may be asymptomatic in children however, continued surveillance of carriers is important to determine the individual adverse prognostic factors of chronic HBV infections.

• Applied Biological Chemistry
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• v.12
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• pp.89-97
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• 1969

These studies were made on coating of fresh fruits and vegetables with PVC under view on preservation of fresh fruits and vegetables due to restrain water evaporation of them and control gas metabolisms. The results obtained, as selection of PVC materials availble for preservation of them, procedure of the coating, useful organic solvents, concentration of PVC solution and the time of dipping, and effects of the preservation of them, were summarized as follows: 1) PVC powder 222 and PVC powder 443 were surveyed as suitable materials for coating apple, and later was excellent in lustrous aspect. 2) The coating procedure which dipt into PVC solution was suitable to treat much within a short space of time, and using of ventillator accelerate rather evaporation of the organic solvent. 3) Aceton and methyethylketon as solvent of the PVC were, in purpose of storage only, avaible, while aceton was, in view ef taste, better. 4) 10% of the PVC solutions were better to preserve the freshness of apple and 5, 4, 1 and 0.5% of them in order were gradually decreased in preservability, and 15% of them as high concentration were looked like fermentation in one week after the coating. 5) The dipping time was also better n minute than 10 seconds in a preservation but 1-2 minutes could be applied owing to be not affected of the taste due to coating. 6) The freshness of treatment groups were extend about 48 days after coating in room temperature but control lost market value with 12 days. 7) Weight of control was decreased to 10-13% but treatment which was dipped into 10% of coating solution for one minute was decreased to 3.5-4.6% and treatment for four minutes was did to 2.9-3.0%. 8) Change in respiration was less is treatment groups than control in exhaustion of $CO_2$, and water soluble sugar, reduced sugar and pH were not changed almost due to coating. 9) Pannel discussion of the taste was indicated that control was better than treatments soon after coating, but treatments were rather than control last period of storage and treatment with aceton solvent specially was better than others.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.2 no.1
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• pp.21-29
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• 1999

Purpose: The aims of this study are to examine clinical characteristics, patterns of medical care utilization, and factors which determine medical care utilization of elementary school children with recurrent abdominal pain (RAP), to find posssible factors influencing the onset and the course of the disorder. Method: We performed questionnaires in Kwangju on children from two primary schools from June,1 1998 to June 30 and carried out statistical analysis. Result: 1) Total number of questionnaires were 1417. 715 were male and 702 were female and the ratio of male to female was 1.02:1. Average age was 10.3 years. 2) 268 children had RAP (18.9%), boys 132 (18.4%), girls136 (19.2%). 3) The duration of the pain within 10 minutes was 68.5%. 178 children with RAP (66.3%) visited the doctor. The utilization pattern of medical facilities of the pupils with RAP; the most frequently utilized medical facility was pediatrics (35.2%) and the order ran as internal medicine (31.5%), and pharmacy (29.25). The utilization pattern of medical facilities for the older students; the utilization rate of pediatrics decreased, but internal medicine increased. The major factors affecting the selection of the medical facility were geographic accessibility, kindness of the personnel, good results and traffic convenience. 4) Symptoms which were accompanied with abdominal pain were headache (44.5%), chest pain (28.2%), dizziness (26.6%), vomiting (9%), and 119 children (44.5%) had no accompanied symptoms. 5) In 95 children (35.3%) abdominal pain, occured at postprandial time, in 55 children (20.5%) before meal and in 39 children (14.7%) at school. The highest incidence rate of RAP was observed on Monday (21.4%), and the lowest on Saturday (8.7%). 6) The most frequent involved part of the abdomen was periumbrical area (38%) and the order ran as epigastrium and suprapubic area. The most frequent characteristics of abdominal pain were burning pain (36.9%) and the order ran as dull, cramping and colicky pain. Conclusion: RAP is a frequent disease entitiy in children. Too many times children with RAP are treated by other departments instead of Pediatrics. A child has a peculiar growth and development which is different to those from an adult with advancing years. So, it is necessary to choose special medical care and an adequate medical facility.

• Childhood Kidney Diseases
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• v.8 no.1
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• pp.33-42
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• 2004

Purpose : Children with nephrotic syndrome(NS) are under high risk for metabolic bone disease(MBD) as a complication of long-term glucocorticoid therapy. We prospectively evaluated the effect of oral bisphosphonate(alendronate) therapy in children with NS, which has proven efficacy in adult patients with glucocorticoid induced MBD. Methods : Among 58 children with NS, aged 5 to 8 years and haying a disease duration of more than 2 years, 30(51.7%) were enrolled to meet the selection criteria, less than -1.0 Z-scores of lumbar spine bone mineral density(BMD) by dual energy X-ray absorptiometry (DEXA). These 30 children were divided into three groups and each were assigned to receive alendronate, calcitriol, and no-medication, respectively for one year. Lumbar spine BMD was followed up every 6 months and the biochemical indexes were measured before and 1 year after the treatment. There were no significant difference among groups with respect to the average age, the initial BMD, and the cumulative steroid doses. Analysis of the treatment efficacy was done by the % change of BMD and by the changes in Z-scores of lumbar spine BMD. Results : Mean age and disease duration of patients at the initial lumbar spine BMD evaluation was $7.4{\pm}1.7$ years and $2.2{\pm}1.2$ years, respectively. Twenty-three of 30 children(76%) had osteopenia, and seven(23%) had osteoporosis. There was no difference in the biochemical values among the groups, before and 1 year after the treatment(P<0.05). Twenty two children(73.3%) with frequent relapsing or steroid dependant NS had more frequent MBD, compared to the 8 children(26.6%) with infrequent relapsing NS. The one year % changes of BMD were 8.56 in alendronate group, 5.79 in calcitriol group, and 1.9 in no-medication group. The changes in Z-score of lumbar spine BMD increased in the alendronate group and the calcitriol group, but not in the no-medication group. One year % changes of BMD were different among groups(P=0.0002). Significant differences were found between the alendronate and the no-medication group, and between the calcitriol and the no-medication group(P<0.05). There was no difference between the alendronate and the calcitriol group. No serious adverse effect was observed in the alendronate group. Conclusion : Children with NS receiving high dose steroids are under the high risk of BMD and should undergo regular BMD evaluation. Z-score of lumbar spine BMD was a useful parameter in diagnosing low bone mass in children. Alendronate weekly oral therapy was effective and relatively safe in increasing the lumbar spine BMD in children with NS having steroid induced MBD.