• Progress in Medical Physics
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• v.24 no.2
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• pp.99-107
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• 2013

The surgical resection was occurred mainly in liver metastasis before the development of radiation therapy techniques. Recently, Radiation therapy is increased gradually due to the development of radiation dose delivery techniques. 18F-FDG PET image showed better sensitivity and specificity in liver metastasis detection. This image modality is important in the radiation treatment with planning CT for tumor delineation. In this study, we applied automatic image segmentation methods on PET image of liver metastasis and examined the impact of image factors on these methods. We selected the patients who were received the radiation therapy and 18F-FDG PET/CT in Korea Cancer Center Hospital from 2009 to 2012. Then, three kinds of image segmentation methods had been applied; The relative threshold method, the Gradient method and the region growing method. Based on these results, we performed statistical analysis in two directions. 1. comparison of GTV and image segmentation results. 2. performance of regression analysis for relation between image factor affecting image segmentation techniques. The mean volume of GTV was $60.9{\pm}65.9$ cc and the $GTV_{40%}$ was $22.43{\pm}35.27$ cc, and the $GTV_{50%}$ was $10.11{\pm}17.92$ cc, the $GTV_{RG}$ was $32.89{\pm}36.8$4 cc, the $GTV_{GD}$ was $30.34{\pm}35.77$ cc, respectively. The most similar segmentation method with the GTV result was the region growing method. For the quantitative analysis of the image factors which influenced on the region growing method, we used the standardized coefficient ${\beta}$, factors affecting the region growing method show GTV, $TumorSUV_{MAX/MIN}$, $SUV_{max}$, TBR in order. The result of the region growing (automatic segmentation) method showed the most similar result with the CT based GTV and the region growing method was affected by image factors. If we define the tumor volume by the auto image segmentation method which reflect the PET image parameters, more accurate and consistent tumor contouring can be done. And we can irradiate the optimized radiation dose to the cancer, ultimately.

• Clinical and Experimental Pediatrics
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• v.50 no.5
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• pp.436-442
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• 2007

Purpose : To promote awareness and efforts by pediatricians to identity and prevent child abuse by investigation of characteristics of victim and types of injury caused by abuse. Methods : A retrospective study was performed with 20 patients who had been diagnosed or suspected as child abuse at Hallym University Hospital from January 1999 to December 2005. The medical records, radiologic documents, and social worker's notes were reviewed to investigate age, sex, visiting time, form of abuse, perpetrator, risk factor, and type of injury. Results : The mean age of the subjects was 2.8 years. Fourteen patients were between 0-1 years old, 2 patients between 1-6 years old, 3 patients between 7-12 years old, and 1 case over 13 years old. The ratio of male to female was 1:1. The majority of these patients (70%) visited via emergency department. Eight five percent of these patients reported with physical abuse, 5% psychological abuse, 5% sexual abuse, and 5% neglect respectively. The suspected perpetrator was the biological father in six cases, the biological mother in three cases, the stepmother in two cases, caregiver in one case, relatives in one case and "unknown" in six cases. Bruise and hematoma (80%) were the most common physical findings. Skull fractures were diagnosed in six cases, long bone fractures in two cases, hemoperitoneum in two cases, subdural hemorrhage in 10 cases, epidural hemorrhages in two cases, subarachnoidal hemorrhages in two cases, and retinal hemorrhages in five cases respectively. Seventeen cases required hospitalization and surgical operations performed were in nine cases. Four patients died and three patients had sequalae such as developmental delay and quadriplegia. Conclusion : Child abuse results in high mortality and morbidity in victims. Therefore early recognition and prevention is very important. Pediatricians should always suspect the possibilities of abuse in cases of fracture, intracranial hemorrhage, abdominal injury, or even any injury to the body. We recommend that the clinical investigation of suspicious children should include a full multidisciplinary social assessment, a skeletal survey and CT or MRI.

• Journal of Bio-Environment Control
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• v.23 no.2
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• pp.158-166
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• 2014

This experiment has investigated suitable methods to improve precision water content monitoring of coconut coir substrates to control irrigation by frequency domain reflectometry(FDR) sensors. Specifically, water content changes and variations were observed at different sensing distances and positions from the irrigation dripper location, and different spaces between the FDR sensors with or without noise filters. Commercial coconut coir substrates containing different ratios of dust and chips(10:0, 7:3, 5:5, 3:7) were used. On the upper side and the side of the substrates, a FDR sensor was used at 5, 10, 20, 30cm distances respectively from the irrigation dripper point, and water content was measured by time after the irrigation. In the glass beads, sensors were installed with or without noise filtering. Closer sensing distance had a higher water content increasing rate, regardless of different coir substrate ratios. There were no differencies of water content increasing rates in 10:0 and 3:7 substrates between the upper side and the side. Whereas, 7:3 and 5:5 substrates showed higher increasing rates on the upper side measurements. Substrates with higher ratios of chip(3:7) had lower increasing rates than others. And, with noise filters, the exatitude of measurement was improved because the variation and deviation were reduced. Therefore, in coconut coir with FDR sensors, an efficient water content measurment to control irrigations can be achieved by installing sensors closer to an irrigation point and upper side of substrates with noise filters.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.2
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• pp.193-208
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• 2020

In this study, we investigate the effects of technology innovation investments and employment on credit ratings of very small start-up businesses using the data period of 2009 till 2015 test two hypotheses: asymmetric information hypothesis or competence hypothesis. We use financial and non-financial data of 51,903 observations of 12,028 small businesses from a database of a commercial bank and fixed effects panel models and two-stage instrumental variable models. We find that in the short-run small size startups show lower credit ratings than non-startups, and that both technology innovation activities and employment capability improve their credit ratings. In the long-run, technology innovation investments do not improve their credit ratings of later years while employment capability improve their credit ratings of the subsequent year. In addition, the age of startups improves their credit ratings of the current year and until the subsequent two years while employee productivity, fixed ratio and ROA positively affect their credit ratings for up to three years. However, short-term and overall debt ratios, cost of borrowings and firm-size negatively affect their credit ratings for up to three years. The results of the study on credit ratings suggest that credit rating agencies seem to consider both technology innovation activities and employment capability in the credit ratings of small start-ups as 'competence factors' rather than 'asymmetric information factors' with inefficiency and cost burdens. The results also suggest that we must find ways to reflect properly the severe asymmetric information of the early-stage start-ups, and technology innovation activities and employment capability in the credit rating formula.

• Pediatric Infection and Vaccine
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• v.15 no.2
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• pp.152-161
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• 2008

Purpose : Staphylococcal scalded skin syndrome (4S) is uncommon, but reports of 4S are on the increase during the recent years. The purpose of this study is to determine the clinical features and associated factors of 4S during the recent 10 years. Methods : We retrospectively reviewed the medical records and microbiologic results of 63 patients (27 neonates and 36 children) from January 1998 to December 2007. Results : Since 2003, the incidence of 4S has increased. The mean age of the patients was 16.3 months and the gender ratio was 1:1. The clinical types of 4S were 38 cases of the abortive type (60%), 19 cases of the intermediate type (30%) and 6 cases of the generalized type (10%). The culture results were 36 cases of Methicillin resistant S. aureus (MRSA), 4 cases of Methicillin sensitive S. aureus and 17 cases of no growth. The patients were treated with semi-synthetic penicillin. For the 9 patients who had MRSA isolated and who didn't improve with penicillin, they were treated with vancomycin instead of penicillin. All the patients had no complications. 4S abruptly increased in 2005, and especially in neonates, due to an MRSA outbreak at a local nursery room. The associated factors of 4S in neonates were hospitalization (27 cases), including nursery infection in 2005 (18 cases) and dermatitis (1 case). There was an unknown origin for some children, and the suggested factors for their infection were community acquired infection (24 cases), atopic dermatitis (9 cases) and hospitalization (3 cases). Conclusion : 4S has recently been increasing. The major associated factors of 4S are a history of hospitalization, an outbreak in a nursery room, atopic dermatitis and community acquired infection.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.1
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• pp.1-7
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• 2005

Tidal flats have been regarded to carry out transformation and removal of land-derived organic matter, and this purifying capability of organic matter by tidal flats is one of very important reasons for their conservation. However, integral biogeochemical studies on production and decomposition of organic matter by benthic microbes in tidal flats have been absent in Korea, although the information is indispensable to quantification of the purifying capability. Our major goals in this multidisciplinary research were to understand major biogeochemical processes and rates mediated by diverse groups of microbes dominating material cycles in the tidal flats, and to assess the contribution of benthic microbes to removal of organic matter and nutrients in the tidal flats. Our study sites were Ganghwa and Incheon north-port tidal flats that had been regarded as naturally well reserved and organically polluted, respectively. Our research group measured over 3 years primary production, biomass and community structure of primary producers, abundance and production of bacteria, enzyme activities, distribution of protozoa and protozoan grazing rates, rates of denitrification and sulfate reduction, early sediment diagenesis, primary production and respiration based on oxygen microelectrode. We analyzed major features of each biogeochemical process and their interactions. The results are compiled in the following articles in this special issue: An (2005), Hwang and Cho (2005), Mok et at. (2005), Na and Lee (2005), Yang et at. (2005), and Yoo and Choi (2005).

• Korean Journal of Ecology and Environment
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• v.47 no.4
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• pp.319-327
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• 2014

Understanding and quantifying of carbon storage in ecosystem is very important factor for predicting change of global carbon cycle under the global climate change. We estimated total ecosystem carbon in Gyeryongsan National Park with naturally well preserved ecosystem in Korea. Vegetation of Gyeryongsan National Park was classified with mainly four communities with Quercus mongolica (1,743.5 ha, 38.0%), Quercus variabilis (1,174.0 ha, 25.6%), Quercus serrata (971.9 ha, 21.2%), Pinus densiflora (695.2 ha, 15.2%). Biomass and soil carbons were calculated from biomass allometric equations based on the DBH and carbon contents of soil and litter collected in quadrat in each community. The tree biomass carbon was in Quercus variabilis ($130.1tCha^{-1}$), Pinus densiflora ($111.1tCha^{-1}$), Quercus mongolica ($76.2tCha^{-1}$), Quercus serrata ($39.0tCha^{-1}$). Soil carbon storage was in Quercus mongolica ($159.7tCha^{-1}$), Quercus serrata ($121.0tCha^{-1}$), Pinus densiflora ($110.5tCha^{-1}$), Quercus variabilis ($90.8tCha^{-1}$). Ecosystem carbon storage was Pinus densiflora ($239.9tCha^{-1}$), Quercus mongolica ($235.9tCha^{-1}$), Quercus variabilis ($226.0tCha^{-1}$), Quercus serrata ($165.9tCha^{-1}$), total amount was $867.7tCha^{-1}$. The area of each vegetation carbon storage was Quercus mongolica ($411,200tCha^{-1}$), Quercus variabilis ($265,300tCha^{-1}$), Pinus densiflora ($166,800tCha^{-1}$), Quercus serrata ($161,200tCha^{-1}$) and the total ecosystem carbon amount estimated $1,045,400tCha^{-1}$ at Gyeryongsan National Park. Theses results indicate that different in naturally well preserved ecosystem.

• Korean Journal of Ecology and Environment
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• v.46 no.4
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• pp.551-560
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• 2013

Environmental factors and epilithic diatom communities in the lower streams near the harbor region of South Korean peninsula were examined during no monsoon period in May 2013. The sampling of water and epilithic diatoms was conducted at both streams, 19 regulated streams (RS) that there are one or several dams constructed in the river system, and 19 un-regulated streams (US) that there are no dams within the river. A cluster analysis based on the number of species and abundance of epilithic diatoms through the stations, divided into three groups such as groups I (mainly US), II (mixed with US and RS) and III (mainly RS), respectively. Group I showed that water quality is good and high diversity of diatom, while Group II and III was water quality is relatively poor, but not differed in biomass of diatom from Group I. In addition, Group II that had high conductivity, nitrogen and phosphorus, was the lowest in diatom diversity among them. Dominant species were Nitzschia palea (17%) and Navicula seminuloides (11%) in Group I, Nitzschia inconspicua (19%) and Navicula perminuta (9%) in Group II, and Nitzschia inconspicua (15%) and Nitzschia palea (14%) in Group III, respectively. These taxa were widely distributed in brackish water, and not closely related with specific water quality, like eutrophic water. However, the groups II and III belonged to RS, had not only little biomass, but bad water quality such as high concentrations of nutrient and chlorophyll-a. Therefore, to determine the effect of dam construction on the lower water ecosystem, the planktonic algae, which can occur algal bloom in the estuary, also was considered to be a parallel investigation.

• Journal of agricultural medicine and community health
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• v.30 no.3
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• pp.279-292
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• 2005

Objectives: The purpose of this study is to analyze agricultural accident and disease using statistical data and materials about National Survey for Health & Nutrition in 2001 and to provide fundamental materials for studies about farmers' health and safety, decision of priority about research and policy. Results: Diagnosed chronic disease prevalence is 72.4% in farmer/fisher group, 49.8% in non farmer/fisher group. The chronic disease prevalence of musculoskeletal disease, circulatory disease, and gastroenteric disease is 46.5%, 18.2%, and 17.9% in farmer/fisher group respectively. The prevalence of musculoskeletal disease in farmer/fisher is 2.4 times higher than non farmer/fisher. This result shows that it need to evaluation for risk factors of musculoskeletal disease preferentially. Lifetime accident/poisoning rate is 18.2% In farmer/fisher group and 13.3% in non farmer/fisher group. The types of accidents were fracture>sprain>contusion and the reasons of accidents were traffic accident>falling/sliding. Conclusions: "Bad or very bad" response of farmer/fisher is almost 2 times higher than non farmer/fisher group. The rate of smoking and no exercising in farmer/fisher group is higher than non farmer/fisher group.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.12 no.2
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• pp.192-217
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• 2001

Object：This study was carried out to classify adolescents in runaway shelters by evaluating their psychopathology. And the ultimate purpose is to offer basic data for preventing adolescents‘ runaway and for diversifying runaway shelters suitable for the problem of individual adolescent. Method：128 adolescents who stay in the runaway shelters were asked to complete self-report qeustionnaires including basic sociodemographic data, Child Behavior Check List(CBCL), Minnesota Multiphasic Personality Inventory(MMPI), and Symptom Check List-90-Revised(SCL-90-R). Korean Wechsler Adult Intelligence Scale(K-WAIS)[or Korean Educational Developmental Institute-Wechsler Intelligence Scale for Children(KEDI-WISC)] and Bender-Gestalt test(BGT) were also done by clinical psychologists. Results：The most common age of the subjects were 15-year-old, and they dropped out their schools in the middle school most commonly. Mostly they were from middle class family and their parents' educational level were high school graduates. The first runaway episode was most common in the middleschool period, and their runaways were repeated. The most common frequency of runaways were more than 10 times. About 10% of them abused drugs and about 80% of them abused alcohol. One third of them had experiences of illegal problems and 10% of them engaged in sexual activity for money. 95 adolescents(83%) in CBCL, 42 adolescents(36%) in SCL-90-R, and 70 adolescents(69.3%) in MMPI showed clinical significance. In intelligence test, 22 adolescents(22%) were mentally retarded. In BGT, 35 adolescents(39.4%) manifested brain dysfunction signs. Conclusion：Runaway adolescents in the shelters have variable and severe psychopathology. Their psychopathology is classified as follows；The behavior disorder group, the mood disorder group with anxiety/depression, the somatic disorder group with somatic symptoms, and the psychosis group with possibility of severe psychopathology. Therefore it is very important to evaluate psychiatric problems of runaway adolescents, and specific therapeutic interventions according to their problems are required.