• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.3
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• pp.41-47
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• 2009

Post-tensioned concrete pavement(PTCP) was developed to built long-span concrete pavement(120 m span) and to maintain long-term service life(over 40 years) of concrete pavement. In the present study, research for high-durable concrete was conducted to utilize the advantage of PTCP construction method efficiently. First of all, 20% of fly ash(by binder weight) was replaced to control alkali silica reaction. Second, silica fume was applied to improve the water-permeability and early-age strength. Results of tests for mechanical properties, water-permeability resistance, and surface-scaling resistance of ternary blended cement concrete showed that the early-age strength was improved significantly with addition of silica fume. The water-permeability resistance was improved from "Low" to "Very Low"(ASTM C 1202). However, surface-scaling resistance was decreased with an increase of silica fume, therefore, content of silica fume should be kept in less than 5%(by binder weight) to assure field application considering durability. The results of air-void analysis showed that durability factors were improved since spacing factors were estimated as 250$\pm$15 micron in adjusted mixtures.

• Korean Journal of Plant Resources
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• v.24 no.2
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• pp.160-167
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• 2011

Shallot is a foreign crop introduced from France in 1995 as a new overwintering field crop with an aim to develop as an export crop. During the introductory cultivation trials, several problems were raised such as premature growth depression in early summer, sensitivity to summer moisture, and weakened vigor of the seed bulbs following successive propagations. This study was conducted to develop proper cultural methods based on annual productivity and adaptability of growing area to address and suggest solutions to some of these problems. Bulb weight was 18.7 g and bulb yield per 10a was 4,113 kg in 1995. In 1996, bulb weight increased to 25.8 g, while bulbs yield per 10a deceased to 2,013 kg. This trend continued in 1997 so that bulb weight increased, and yield per 10a decreased as compared to those in 1996. However, in 1998, both bulb weight (21.1 kg) and yield per 10a (1,246 kg) decreased significantly as compared to those of the previous years. Plant growth from planting to April in the coastal area was better than in other areas. However, the plant growth thereafter until early July was better in the semi-highland area. As a result, the bulb yield in the semi-highland area was 57% more than that in the lowland areas such as the coastal area.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.644-656
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• 2014

In recent years, a series of large-scale disastrous accidents have been occurred frequently both in public and private sector. Such disasters become catastrophe due to poor early response and delayed prompt rescue. Damage from catastrophe could have been drastically reduced or minimized with effective response and recovery management. The smart phone-based mobile applications have important potentials in providing solutions for the effective response and recovery management. Mobile applications can greatly improve risk communication in case of disasters by integrating process of exchange information and data on risk among risk evaluators, risk managers, and other interested parties. In this light of potentials, this study investigates the measures and management to better manage early responses and to effectively deal with domestic disaster-related of the status of public applications service, and utilization. This study examines how disaster applications can be better used and how effective information dissemination through applications could help the post-disaster management process. Based on this findings, it proposes a guideline of effective disaster-related applications by public sector for the future development of actual services and activation solutions. The results show that "User Promptness Side" and "Content Believability Side" factors found to be the two most significant factors in the disaster-related applications by public sector. Discussion and implications are discussed.

• Journal of the Korean Wood Science and Technology
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• v.37 no.6
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• pp.566-577
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• 2009

The modification of wood color occurs rapidly during the service period at indoor. It is crucial to investigate the characteristics of color change, chemical and microscopical modification of wood at indoor. Wood products made of Japanese cedar at different years were used for this work. The tests were performed in order to evaluate the degree of color change of wood surface, breakpoint of brightness from surface to inside of wood, chemical analysis with FT-IR, and microscopical characteristics using the LM and TEM. Surface color of cedar wood stored indoor were rapidly changed at early stage, particularly ${\Delta}a$ (yellow), and ${\Delta}b$ (red) values were steeply decreased for one year old indoor wood, ${\Delta}L$ (white) value was dropped until 5 years old indoor wood compared with control sample. Decrease of peaks related to polysaccharide and lignin was noticed, especially, lignin was severely degraded. Although degradation of cell wall limited only to surface layers of indoor wood, degradation pattern of indoor wood showed similar degradation pattern to natural weathering of wood during outdoor weathering or wood behavior under artificial UV irradiation.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.2
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• pp.141-149
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• 2017

To examine the cause of acute diarrheal disease in children and adolescents, 521 fecal samples underwent multiple-PCR for a period of two years, between March 2015 and February 20178, in the Jeju region of Korea. Based on the analysis of 179 positive samples, 102 samples were male (56.98%) and 77 were female (43.02%), and highest positive rates were shown in the age group of 3~4 years (51.96%) and 5~6 years (12.29%). When 209 cases (40.12%), including double infection were analyzed, there were 88 cases (16.89%) of norovirus-GII infection, 26 cases (4.99%) of Campylobacter spp. infection, 18 cases (3.45%) of rotavirus infection, 18 cases (3.45%) of Clostridium difficile Toxin B infection, 17 cases (3.26%) of adenovirus infection, 16 cases (3.07%) of Clostridium perfringens infection, 11 cases (2.11%) of astrovirus infection, 5 cases (0.96%) of Salmonella spp. infection, 3 cases (0.58%) of norovirus-GI, Yersinia spp. and Aeromonas spp. infections, and 1 case (0.19%) of verocytotoxin-producing E. coli infection. Based on a seasonal separation of early childhood, norovirus-GI and norovirus-GII mainly prevailed during the winter, when the temperature is low. Typical enteritis with an increased prevalence of rotavirus during the spring. Astrovirus prevailed between the months of April and October, when norovirus-GI, norovirus-GII, and rotavirus did not prevail. With increasing age, acute diarrheal disease was not only induced by a virus, but also by bacteria. Although a test for virus is an effective method when trying to identify the cause during early childhood by multiplex-PCR, it would be desirable to undergo tests for both virus and bacteria concurrently as age increases.

• Journal of the Korean Society of School Health
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• v.7 no.1
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• pp.9-28
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• 1994

This study is to investigate the status and problems in the anual physical examination in elementary & secondary schools. The study helps the introduction of health assessment. Two hundreds and forty nurse teachers of elementary & seconcary school in Seoul received in-service traomong fpr 20 daus frp, September 7 to September 27, 1992. Questionnaires were given to the 240 teachers and the number of collected questionnaire is 112. The result of the questionnaire analysis is like the following. First, the answered teachers aged 35~39, 36.6%; experience 6~10 years 37.5%; the number of class 31~40, 28.6%. Among the answered of the school doctors is practicioners. The doctors major subjects are 26.8% of internal medicine and 35.7% of surgery. Second, in elementary & secondary school nurse teachers received in-service training for the primary health assessment. And then 37.5% of schools practiced the health assessment. The term of the health assessment is largely a-year-length, occurately its rate of schools have practiced the assessment reaches 81.0%. The number of health assessment are consist of eyes, nose, ear, throat, skin, spine, heart and other abnormal regions and diseases all over the body. And 83.3% of the rate of the health assessment includes all these contents. The period of the health assessment is 7 to 28 days. Third, the physical examination conducted by school doctors is 91.0%. The method is various; one is 56.6% of the students who checked first by he nurse teacher. The number of 15.1% of the schools is directly checked by the school doctor. The invited medical doctors are divided into two categories. The number of general physician is 61.9%. Contrary to that school doctors are 38.1%. The contents of the medical examination is all the items printed on the medical examination sheet. To follow the medical examination sheet the number of school is 59.6%. Eyes, throat, skin and heart etc. partly medical examination is 40.4%. The rate of schools that used only stethoscope, tongue pressor as the medical instruments reaches 53.4% and 87.1% of elementary & secondary school give the invited doctors the allowance a nurse teachers conference decided. The number of 8.9% schools pay the doctors independent allowance. The medical examomatopm allowance is 200 to 250 won per capita. The rate is 56.1%. Forth, after the medical examination 72.1% of school sends letter to the parents to notice the result of the examination. The number of response from parent is 12.5%. The observation record in secondary school is 70.6% for junior, and 80.0% for senior respectively, and 65.5% is for the elementary school children. To conclude the regular physical examination in elementary & secondary school is very important. Because the students are in the stage of rapid growth and development. Early finding of the students diseases can help to cure with ease. In the light of public health the management of health program in the elementary & secondary school is of consequence.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.689-693
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• 2023

Domestic bridges with a service life of more than 30 years are expected to account for approximately 54% of all bridges within the next 10 years. As bridges rapidly deteriorate, it is necessary to establish an appropriate maintenance plan. Recent domestic and international research have focused on the integration of BIM to digitize bridge maintenance information and then enhance accessibility and usability of the information. Accordingly, this study developed a BIM-FEM interoperability algorithm for bridge decks to convert maintenance information into data and efficiently manage the history of maintenance. After creating an initial crack BIM based on an exterior damage map, bridge specification and damage information were linked to a numerical analysis that performs damage analysis considering damage scenarios and design loads. The spread of cracks obtained from the analysis results were updated into the BIM. Based on the damage spread information on the BIM, an automated technology was also developed to assess both the current and future condition ratings of the bridge deck. This approach can enable an efficient maintenance of the deck using the history data from bridge inspection and diagnosis as well as future information on cracks and defects. The expected early detection and prevention would ultimately improve the lifespan and safety of bridges.

• Journal of Preventive Medicine and Public Health
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• v.42 no.6
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• pp.416-423
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• 2009

Objectives : This study was performed to examine medical care utilization of psychiatric patients and to explore patients' characteristics associated with extended hospitalization. Methods : Data were extracted from information of Korean Health Insurance Review and Assessment Service. All data associated with admission and outpatient clinic visit were analysed by patient characteristics. We selected first psychiatric admission patients who diagnosed mental and behavioral disorders due to use of alcohol (main disease code: F10), schizophrenia and related disorders (F20-29) and mood disorders (F30~33) from January to June 2005. We analysed status of admission, mean length of stay, regular access to outpatient clinic and rates of extended hospitalization during 3 years. Bivariate and multivariate analyses were conducted to identify factors associated with extended hospitalization. Results : The number of psychiatric patients during the first six month of 2005 was 30,678. The mean length of stay was longest for schizophrenia and related disorders but shortest for mood disorders. Patients who experienced an extended hospitalization were 18.8% of total subjects. An extended hospitalization was more common in schizophrenia and related disorders than other diagnostic groups. The factors associated with the extended hospitalization were age, sex, diagnostic group, type of insurance and medical care utilization groups. Conclusions : The study indicates the problem of an extended hospitalization for psychiatric patients in Korea. It is suggested that variations in rates of extended hospitalization among medical care utilization group may need an active early intervention system in psychiatric treatment service. Particular attention needs to be devoted to planning and funding for reducing extended hospitalization.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.235-243
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• 2002

Ni-base superalloys are used extensively in industry, both in aeroengines and land based turbines. About 60% by weight of most modern gas turbine engine structural components are made of Ni-base superalloys. To satisfy practical demands, the efficiency of gas turbine engines has been steadily and systematically increased by design modifications to handle higher turbine inlet or firing temperatures. However, the increase in operating temperatures has lead to a decrease in the life of components and increase in costs of replacement. Moreover, around 80% of the large frame size industrial/utility gas turbines operating in the world today were installed in the mid-sixties to early seventies and are now 25 to 30 years old. Consequently, there are greater opportunities now to repair and refurbish the older models. Basically, there are two major factors influencing the weldability of the cast alloys: strain-age cracking and liquation cracking. Susceptibility to strain-age cracking is due to the total Ti plus AI content of the alloy; Liquation cracking is due either to the presence of low melting constituents or constitutional liquation of constituents. Though Rene 41 superalloy has 4.5wt.% total Ti and Al content and falls just below the safe limit proposed by Prager et al., controlled grain size and special heat treatments are needed to obtain crack-free welds. Varying heat treatments and filler materials were used in a laboratory study, then the actual welding of service parts was carried out to verity the possibility of crack-tree weld of components fabricated from Rene 41 superalloy. The microstructural observations indicated that there were two kinds of carbides in the FCC matrix. MC carbides were located along the grain boundaries, while M$_{23}$C$_{6}$ carbide was located both inter and intra granularly. Two kinds of filler materials, Rene 41 and Hastelloy X were used to gas tungsten arc weld a patch into the sheet metal, along with varying pre-weld heat treatments. The microstructure, hardness and tensile tests were determined. The service distressed parts were categorized into three classes: with large cracks, with medium cracks and with small or no visible cracks. No significant difference in microstructure among the specimens was observed. Specimens were cut from the corner and the straight edge of the patch repair, away from the corner. The only cracks present were found to be associated with inadequate surface preparation to remove oxidation. Guidelines for oxide removal and the welding procedures developed in the research enabled crack-free welds to be produced.d.

• Research in Plant Disease
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• v.26 no.4
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• pp.239-249
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• 2020

To find out the cause of the fire blight outbreak in apples and pears of Korea in 2019, we investigated disease appearing situation of thirty fire blight infected orchards, and interviewed farmers to determine the cultivation characteristics. Fire blight occurred mostly in orchards that had infected more than 2 years before. The cause of this were as follows: farmers did not know the symptoms of the disease properly. It is presumed that it has spread from the first occurrence to the surrounding orchards by flower-visiting insects or farmers and to a short distance or a long distance by the same cultivator or co-farmer. These series of processes repeated in the newly spreading area, and then disease reports increased as farmers became aware of fire blight. To minimize the spread of fire blight in Korea, it suggested that thorough education of farmers for early diagnosis and quantitative detection technology that can diagnose even in no symptom showing plants. And chemical or biological spraying systems suitable for domestic cultivation methods, which are producing large fruits, and molecular epidemiological studies of pathogens.