• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.6
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• pp.397-407
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• 2017

In this study, a SCR system is employed to selectively reduce $NO_X$, which is a major cause of environmental pollution and issues in diesel engines. In particular, this paper focuses on the combination of feedforward injection strategies, depending on the NO/$NO_X$ ratio, and feedback injection control, using $NH_3$ coverage ratio, based on a SCR model. A 2.2 L passenger diesel engine, which is equipped with a diesel oxidation catalyst (DOC) and a diesel particle filter (DPF), was used in the experiments. The developed control algorithm is implemented on a real-time computer with injection control algorithm. By analyzing the $NO_X$ emission measurement, the performance of the proposed injection control algorithm is verified.

• Health Policy and Management
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• v.25 no.4
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• pp.285-294
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• 2015

Background: Suicide is one of important health problems in Korea. Previous studies showed factors associated with suicide in individual levels. However, suicide was influenced by society that individuals belong to, so it was required to analyze suicide in local levels. The purpose of this study was to analyze the regional disparities of suicide mortality by gender and the association between local characteristics and suicide mortality. Methods: This study included 229 city county district administrative districts in Korea. Age- and sex-standardized suicide mortality and age-standardized suicide mortality (male/female) were used as dependent variables. City county district types, socio-demographics (number of divorces per 1,000 population, number of marriages per 1,000 population, and single households), financial variable (financial independence), welfare variable (welfare budget), and health behavior/status (perceived health status scores and EuroQol-5 dimension [EQ-5D]) were used to represent the local characteristics. We used hot-spot analysis to identify the spatial patterns of suicide mortality and negative binomial regression analysis to examine factors affecting suicide mortality. Results: There were differences in distribution of suicide mortality and hot-spot regions of suicide mortality by gender. Negative binomial regression analysis provided that city county district types (city), number of divorces per 1,000 population, financial independence, and EQ-5D had significant influences on the age- and sex-standardized suicide mortality per 100,000. Factor influencing suicide mortality was the number of divorces per 1,000 population in both male and female. Conclusion: Study results provided evidences that suicide mortality among regions was differed by gender. Health policy makers will need to consider gender and local characteristics when making policies for suicides.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.2
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• pp.79-87
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• 2010

Objectives: The purpose of this study was to investigate the symptoms of work-related musculoskeletal disorders (WMSDs), the influence of the WMSDs on the health-related quality of life (HRQoL), and to identify the differences of WMSDs and HRQoL between greenhouse farmers and paddy farmers. Methods: Subjects were 34 greenhouse farmers and 56 paddy farmers who were living in a rural community. The sociodemographic characteristics, health-related behavior, working characteristics, WMSDs and HRQoL were investigated. WMSDs symptoms were measured by a selfassessed questionnaire on musculoskeletal disorders symptoms and HRQoL was measured by the Euro Quality of Life (Euroqol) EQ-5D index. The differences on the WMSDs, EQ-5D and it's related factors between the groups were assessed with t-test and ${\chi}^2$-test. Results: Greenhouse farmers were longer the working hours per day and working duration than paddy farmers. The level of prevalence of the WMSDs in greenhouse farmers is higher than in paddy farmers. The EQ-5D index of greenhouse farmers and paddy farmers were 0.819 and 0.874, respectively. Overall, the mean value of EQ-5D index was significantly lower greenhouse farmers than paddy farmers. Conclusions: These results showed that the HRQoL for farmers are strongly influenced by WMSDs and agicultural type in that we are aware of the need to comply with regulations of WMSDs, especially greenhouse farmers.

• Journal of Chest Surgery
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• v.24 no.6
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• pp.533-540
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• 1991

We have performed 14 single lung transplantation in mongrel dogs transplanting the left lung exclusively from December 1989 to January 1991, in the department of thoracic surgery of Seoul National University Hospital. In the donor dogs, the main pulmonary artery was divided proximal to its bifurcation, and the left atrium was incised freeing the left veins with a generous atrial cuff. We used cold saline in the first 7 transplantation[group I ] and a Euro Collins solution in the remaining 7 transplantations[group II ] as a lung preservatives. The bronchus was divided at two cartilage rings proximal to the upper lobe bronchus take off. In the recipient procedure, we used a Fogarty catheter as a bronchus block. Left atrial anastomosis was performed first using 5 - 0 prolene and the pulmonary artery was anastomosed using 6 - 0 prolene. The bronchus was anastomosed next with 4 - 0 Vicryl interruptly and covered with a greater omentum which had been prepared previously. In group I the three dogs died at eleven hours, 5 days, and 14 days, postoperatively and the remaining four doings were killed at 5 days, 5 days, 6 days, and 12 days, respectively. In group II the two dogs died during the operation, one dog died at 6 hours, two dogs died at 6 days postoperatively. Two dogs were killed at 5 days, and 7 days. No significant difference was noted between the two groups in survival time, lung infiltration of transplanted lungs, and perfusion defects in perfusion lung scans. Of the 8 dogs which died naturally, the causes of death were as follows: 2 cases of sepsis, 2 cases of ventricular fibrillations, 2 cases of malnutrition, and 2 cases of respiratory failures.

• Journal of the Korean Society of Safety
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• v.30 no.2
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• pp.56-62
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• 2015

The purpose of this study was to identify the relationship between the index of Electrocardiography(LF/HF) and the occurrence of drowsiness driving while driving in a simulated situation. Participants were 31 undergraduate students with an experience in driving and they participated 30 minutes driving under enough sleep condition and 1 hour under the sleep deprivation condition. The Euro Truck Simulator II was used for driving simulation task and ECG and perceived drowsiness of each participants were measured during two driving conditions. Perceived sleepiness recorded by the checklist every 10 minutes and ECG data extracted before and after 15 seconds of every 10 minutes to verify the relationship between two variables. The results showed that the level of perceived sleepiness under sleep deprivation condition was higher than that under the enough sleep condition, and the level of LF/HF under sleep deprivation condition was lower than that under the enough sleep condition. In addition, the result of analysis of repeated measure ANOVA for ECG indicated that authentic sleepiness revealed in 20 minutes after the start of driving under the sleep deprivation condition. However, the result of perceived drowsiness indicated that authentic sleepiness revealed in 30 minutes after the start of driving. These result suggest that the time difference between biological and perceived response on drowsiness may be exist. Finally, the significant negative correlation between the LF/HF level and perceived drowsiness was observed. These findings suggest that ECG(LF/HF) can be an possible index to measure drowsiness driving.

• The Journal of Korean Medicine
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• v.37 no.1
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• pp.41-52
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• 2016

Objectives: There are no studies which have investigated the health related quality of life(HRQOL) about stroke patients according to the medical care utilization behavior by longitudinal analysis. The purpose of this study is to analyze the quality of life(QOL) and quality adjusted life years(QALYs) of stroke patients of western and combined treatment group by longitudinal analysis. Methods: A retrospective cohort study was conducted among 37 new patients who initiated diagnosis with stroke in 2009 from Korea Health Panel Data. We analyzed the HRQOL of stroke patients and calculated the QALYs after medical use initiation for up to 3 years according to the medical care utilization behavior. Results: Overall, the quality of life of stroke patients was lowered somewhat from 0.8431 to 0.7864 in 2009~2012. Western treatment group was appeared slightly declined in from 0.8527 to 0.8231 and combined treatment group was shown to be falling from 0.8173 to 0.6875. The QALYs of total patients were calculated 2.3654 and western treatment group were 2.4436, combined treatment group were 2.1542 during the 4 year period. The difference of QALYs between two groups was 0.2894 QALYs. Conclusions: Although there was a small difference in QALYs of the two groups, it is not certain that the difference is come from medical care utilization behavior. Further studies should be needed to confirm the relation of the medical care utilization behavior and quality of life by considering severity of the stroke.

• Journal of the Korean Institute of Gas
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• v.17 no.1
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• pp.1-6
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• 2013

Using natural gas-hydrogen blended fuel (HCNG) in a heavy duty vehicle is regarded as an alternative to meet reinforced emission regulation compared to a recent direct injection (DI) diesel engine. Hydrogen can lead stable lean combustion even under leaner mixture condition than natural gas, so that improving not only thermal efficiency but also $NO_x$ emissions. In the present study, the feasibility of HCNG engine's commercialization was accessed with HCNG fuel (30% $H_2$ and 70% natural gas) in aspect to the reliability and possibility to reduce $NO_x$ emissions by the level of EURO-VI under various operating conditions.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.220.2-220.2
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• 2011

Biodiesel and biodiesel blend fuel are receiving increasing attention as alternative fuels for diesel engines without substantial modifications. Biodiesel fuels and blending have been widely studied and applied in diesel engine because of biodiesel's lower sulfur, lower aromatic hydrocarbon and higher oxygen content. Biodiesels have the potential to be oxidized in different condition. It has reported that oxidation deterioration of biodiesel is different in the condition of storage and oxidation causes chemical property change of methyl esters. Sunlight intensity, temperature, material of container and contact surface with oxygen are key dominant factors accelerating oxidation deterioration. In this study, we chose temperature among key oxidation conditions and metal container filled with biodiesel was heated at about $110^{\circ}C$ for 10 days in order to accelerate oxidation deterioration. To better understand the effect of biodiesel blends on emission, steady state tests were conducted on a heavy duty diesel engine. The engine was fueled with Ultra Low Sulphur Diesel(ULSD), a blend of 10% and 20%(BD10, BD20) on volumetric basis, equipped with a common rail direct injection system and turbocharger, lives up to the requirements of EURO 3. The experimental results show that the blend fuel of normal biodiesel with BD10 and BD20 increased NOx. The result of PM was similar to diesel fuel on BD10, but the result of PM on BD20 was increased about 63% more than its of diesel. The blend fuel of Oxidation biodiesel with BD10 and BD20 increased NOx as the results of normal biodiesel. But PM was all increased on BD10 and BD20. Especially THC was extremely increased when test fuel contains biodiesel about 140% more than its of diesel. Through this study, we knew that oxidation deterioration of biodiesel affects emission of diesel engine.

• Journal of Oriental Neuropsychiatry
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• v.25 no.3
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• pp.225-234
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• 2014

Objectives: The purpose of this study is to investigate the effects of M&L Self-Growth Meditation Program with Euro QOL-5 Dimension (EQ5D), Five Facet Mindfulness Questionnaire (FFMQ) and psychological test. Methods: 6 middle-age women have participated in the eight weeks of the M&L Self-Growth Meditation Program, and the program was executed once a week for about two hours. We evaluated EQ5D, FFMQ, Beck Depression Inventory (BDI), State-Trait Anxiety Inventory (STAI), and State-Trait Anger Expression Inventory (STAXI) before and after the program in order to analyze the effects of M&L Self-Growth Meditation Program. Results: 1) EQ5D scores increased significantly (p<0.05), and overall physical condition scale( VAS) increased. 2) In the FFQM scores, value of Nonreactivity increased significantly (p<0.05), and total score increased. 3) Scores of BDI and STAI-S decreased significantly (p<0.05), and STAI-T, STAXI-S, STAXI-T, STAXI-O, STAXI-Su, and STAXI-R decreased. Conclusions: The results suggested that M&L Self-Growth Meditation Program improves the quality of life and mindfulness skill and has a positive responses to psychological problems-depression, anxiety, and anger.

• Journal of Korean Society of Steel Construction
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• v.15 no.1
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• pp.25-31
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• 2003

This research aimed to experimentally and theoretically investigate the moment strength of deck plates. A moment experiment was carried out using a full-scale 14 specimen. To prevent local buckling, the point load was applied at 1/4 points. After the experiment, theoretical analysis was conducted and the differences between various codes were identified. The experimental results were compared with AISI (the American Iron and Steel Institute), EC (Euro Code) 3, and KS (Korea Standard) codes. Analysis results are summarized as follows: (1) the failure mode was influenced by local buckling at the midpoint of the beam and/or at the intermediate loading point: (2) if yielding first occurred at the tension side, the moment strength would increase as the plastic reservation of the tension zone acted: (3) the experimental results were closest to the EC3 codes in which the partial plastic reservation was considered; (4) statistical evaluation based on the EC3 Annex Z showed that the partial resistance safety coefficient calculated applying to the EC3 formula, $^{\circ}{_M}$, was placed within 1.1 which was the target value of EC3 code; and (5) the analytical power of AISI and KS codeswere expected to improve into the level of EC3 codes if the concept of plastic reservation of the tension side would be introduced to them.