• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.53-59
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• 2010

A fatigue damage caused by cyclic load is considered as one of the important failure mechanisms that threaten the integrity of structures and components in a nuclear power plant. In ASME code section III NB, the fatigue analysis procedure and standard S-N curves for the class 1 components are described and these criteria should be met at the design step of components. As the current ASME S-N curves are based on the very conservative assumptions such as a local stress concentration effect, immoderate transient frequencies and a constant Young's modulus, however, they can not precisely address the fatigue behavior of components. In order to find out the technical solution for these problems, a number of researches and discussion have been carried out continuously at home and abroad over the decades. In this study, detailed fatigue analyses for DVI nozzle with various mesh density of finite elements were performed to evaluate effect of stress concentration factors on the fatigue analysis procedure and the excessive conservatism of stress concentration factors are confirmed through the analysis results.

• Journal of Korean Society of Rural Planning
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• v.18 no.3
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• pp.67-76
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• 2012

The purpose of this study is to analyze the landscape preference and landscape images of the Agricultural Aqueduct Bridges(AAB) by several different criteria. Semantic Differential Scale(SD scale) with landscape adjectives and landscape preference are used to estimate the alternatives of the AAB. The statistic methods such as descriptive analysis, t-test, factor analysis and regression, cluster analysis, are operated. The landscape preference of the alternatives is generally positive, 3.977 out of 7.000. The gate type is the most preferred, but the road-along type is the worst, by the location types. The simple repair type is the worst preferred, but total remodeling is the most, by the repair types. The characteristics of the AAB are analyzed and 4 factors of visual landscape are contracted; interest, orderliness, naturality and spatiality. Cumulative factor loading of these factors is about 65%, which is quite high. The higher and bigger AAB's are preferred, and the advanced finishing materials are also preferred, such as aluminum or wood panels. The long span is also preferred and the high repair cost would be preferred. But in this study, the cost-benefit analysis is not included, so it is recommended to research further, considering the cost variable with the visual factors.

• Earthquakes and Structures
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• v.7 no.3
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• pp.251-269
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• 2014

To investigate the seismic performance and to obtain quantitative parameters for the requirement of performance-based bridge seismic design approach, 12 reinforced concrete (RC) hollow rectangular bridge column specimens were tested under constant axial load and cyclic bending. Parametric study is carried out on axial load ratio, aspect ratio, longitudinal reinforcement ratio and transverse reinforcement ratio. The damage states of these column specimens were related to engineering limit states to determine the quantitative criteria of performance-based bridge seismic design. The hysteretic behavior of bridge column specimens was simulated based on the fiber model in OpenSees program and the results of the force-displacement hysteretic curves were well agreed with the experimental results. The damage states of residual cracking, cover spalling, and core crushing could be well related to engineering limit states, such as longitudinal tensile strains of reinforcement or compressive strains of concrete, etc. using cumulative probability curves. The ductility coefficient varying from 3.71 to 8.29, and the equivalent viscous damping ratio varying from 0.19 to 0.31 could meet the requirements of seismic design.

• Journal of Veterinary Clinics
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• v.36 no.1
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• pp.30-37
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• 2019

The purpose of this present study was to objectively evaluate gastrointestinal and bone marrow AEs after administration of various chemotherapeutic agents in canines with malignant tumors, using the Veterinary Cooperative Oncology Group-Common Terminology Criteria for Adverse Events (VCOG-CTCAE), which includes descriptive terminology used for adverse events (AEs) reported in dogs and cats. The medical records of 42 dogs with malignant tumor that underwent chemotherapy were reviewed retrospectively. There were no significant differences in the prevalence of gastrointestinal AEs among the 5 chemotherapeutic agents (vincristine, cyclophosphamide, doxorubicin, lomistine, and carboplatin). The prevalence of bone marrow AEs was significantly higher after administration of lomustine than after administration of vincristine or doxorubicin. Grade 1 AEs of the gastrointestinal tract and bone marrow were most often observed after administration of various chemotherapeutic agents. Delayed and cumulative myelosuppression of lomustine in some dogs receiving regular blood examination were identified. The findings of this study will help predict possible gastrointestinal and bone marrow AEs due to the use of chemotherapeutic agents to treat canines with malignant tumors.

• Journal of Wetlands Research
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• v.18 no.2
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• pp.121-131
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• 2016

The determination of feasible design flood is the most important to control flood damage in river management. Concentration time and storage constant in the Clark unit hydrograph method mainly affects magnitude of peak flood and shape of hydrograph. Model parameters should be calibrated using observed discharge but due to deficiency of observed data the parameters have been adopted by empirical formula. This study is to suggest concentration time and storage constant based on the observed rainfall-runoff data at GongDo stage station in the Ansung river basin. To do this, five criteria have been suggested to compute root mean square error(RMSE) and residual of oserved value and computed one. Once concentration time and storage constant have been determined from three rainfall-runoff event selected at the station, the five criteria based on observed hydrograph and computed hydrograph by the Clark model have been computed to determine the value of concentration time and storage constant. A criteria has been proposed to determine concentration time and storage constant based on the results of the observed hydrograph and the Clark model. It has also been shown that an exponent value of concentration time-cumulative area curve should be determined based on the shape of watershed.

• Journal of Preventive Medicine and Public Health
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• v.33 no.3
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• pp.343-348
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• 2000

Objectives : This study was conducted to integrate the results of studies assessing the association between chronic noise exposure and blood pressure. Methods : Using a MEDLINE search with noise exposure, blood pressure and hypertension as key words, we retrieved articles from the literature that were published from 1980 to December 1999. The criteria for quality evaluation were as follows: 1) the study subjects must have been workers employed at a high noise level area 2) The paper should use average and cumulative noise exposure as method for exposure evaluation. 3) Blood pressure in each article should be reported in a continuous scale Among the 77 retrieved articles, six studies were selected for quantitative meta-analysis. Before the integration of the regression coefficients for the association between blood pressure and noise level, homogeneity tests were conducted. Results : All studies were a cross-sectional design and the study subjects were industrial workers. Five papers used a time-weighted average for noise exposure and only one paper calculated the cumulative noise exposure level. The measurement of blood pressure in the majority of studios were accomplished in a resting stale, and used an average of two or more readings. The homogeneity of studies was rejected in a fixed effect model, so we used the results in a random effect model. The results of the quantitative meta-analysis, the weighted regression coefficient of noise associated with systolic blood pressure and diastolic blood pressure were 0.05 (95% confidence interval [CI]: -0.03, 0.13) and 0.06 (95% CI: -0.01, 0.13), respectively. Conclusions : Our results suggested that chronic exposure to industrial noise does not cause elevated blood pressure.

• Journal of Bio-Environment Control
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• v.11 no.1
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• pp.12-17
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• 2002

Tn establish the criteria for appropriate seedling production method in the summer, the effect of container size and seedling age on the growth and yield were evaluated with tomato. The seedling quality was higher when seedlings were grown polyethylene in 9cm pots than in 72 cell plugs. Seedling quality increased with increase in seedling age in polyethylene pots, whereas seedling age did not affect seedling quality in plug trays. Fruits matured earlier on plants started from pot-grown transplants for a long duration than with plug tray-grown transplants for a shorter duration. Not only total yield in 4 months, but the early yield in the first 2 months, was higher with pot-nursed transplants than with plug tray-nursed transplants. With pot-grown transplants, The early yield in initial 2 months was the lowest in 25 day-old transplants, whereas there was no significant differences between 35- and 45-day-old transplants. Seedling age did not affect the cumulative yield for 3 months after the first harvest. With plug tray-grown transplants, the cumulative yield tar initial 3 months was the highest in plants grown for 35 days in the nursery, followed by 25 day and 45 day. However, there were no significant differences among seedling ages in the total yield.

• Journal of Korea Water Resources Association
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• v.49 no.4
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• pp.275-282
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• 2016

The objective of this study is to propose a new method to determine the drought event and the design drought severity. In order to define a drought event from precipitation data, theory of run was applied with the cumulative rainfall deficit. When we have a large amount of rainfall over the threshold level, in this study, we compare with the previous cumulative rainfall deficit to determine whether the drought is relieved or not. The recurrence characteristics of the drought severity on the specific duration was analyzed by the conditional bivariate copula function and confidence intervals were estimated to quantify uncertainties. The methodology was applied to Seoul station with the historical dataset (1909~2015). It was observed that the past droughts considered as extreme hydrological events had from 10 to 50 years of return period. On the other hand, the current on-going drought event started from 2013 showed the significantly higher return period. It is expected that the result of this study may be utilized as the reliable criteria based on the concept of return period for the drought contingency plan.

• Journal of Korea Water Resources Association
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• v.56 no.11
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• pp.823-835
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• 2023

Recently, due to the increase in abnormal climate, rainfall intensity is increasing and drought periods are continuing. These environmental changes lead to prolonged drought conditions and difficulties in real-time recognition. In general, drought can be judged by the amount of precipitation and the number of days without rainfall. In determining the impact of drought, it is divided into meteorological drought, agricultural drought, and hydrological drought and evaluation is made using the drought index, but environmental drought evaluation is insufficient. The river water quality managed through the total water pollution cap system is vulnerable to the effects of such drought. In this study, we aim to determine the drought impact on river water quality and quantify the impact of prolonged drought on water quality. The impact of rain-free days and accumulated precipitation on river water quality was quantitatively evaluated. The Load Duration Curve (LDC), which is used to evaluate the water quality of rivers, was used to evaluate water pollution occurring at specific times. It has been observed that when the number of consecutive rainless days exceeds 14 days, the target water quality in the mid-basin is exceeded in over 60% of cases. The cumulative rainfall is set at 28 days as the criteria, with an annual average rainfall of 3%, which is 32.1 mm or less. It has been noted that changes in water quality in rivers occur when there are 14 or more rainless days and the cumulative rainfall over 28 days is 32.1 mm or less in the Gamcheon Mid-basin. Based on the results of this study, it aims to quantify the drought impact and contribute to the development of a drought water quality index for future environmental droughts.

• Clinical and Experimental Reproductive Medicine
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• v.12 no.2
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• pp.15-23
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• 1985

Therapy for anovulation represents one of the more gratifying and successful type of infertility management. Despite the introduction of bromocriptine, human menopausal gonadotropin (HMG), and gonadotropin releasing hormone (GnRH), clomiphene citrate remains the mainstay of ovulation induction therapy. There is wide variability in reported rates of ovulation induction (57-91%) and conception (25-43%) following clomiphene therapy. Factors contributing to this variability among different reports are the differences in dosage and duration of therapy, different criteria utilized in selecting patients for clomiphene therapy and different luteal phase parameters of presumptive ovulation. A review of recent experience with clomiphene citrate in the Department of Obstetrics and Gynecology in Seoul National University from January, 1983 to May, 1985 yields the following conclusions: 1. Ovulation rate per total patients treated was, 69.0% 2. Pregnancy rate per total patients treated was 31.7%, and that per total patients ovulated was 45.9%. 3. Ovulation rate at the dosage level up to 150 mg/day (50.3-53.8%) was somewhat higher than that at 200 mg/day or more (33.3-34.6%), and pregnancy rate per total patients treated was comparable at each dosage level. 4. Ovulation rate per total patients ovulated at each dosage level, where ovulation and conception occurred, showed a decreasing tendency as the dosage increased, but pregnancy rate per total patients conceived was comparable except at 200 mg/day. 5. Cumulative pregnancy rate per total patients conceived in each ovulatory cycle was 68.9% in 3 cycles, 88.9% in 4 cycles, and 100% in 6 cycles.