• International conference on construction engineering and project management
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• 2011.02a
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• pp.256-261
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• 2011

Labor productivity is a significant factor related to control time, cost, and quality. Many researchers have developed models to define method of measuring the relationship between productivity and various constraints such as the size of working area, maximum working hours, and the crew composition. Most of the previous research has focused on estimating productivity; however, this research concentrates on estimating labor productivity and developing time and cost data for repetitive concrete pouring activity. In Korea, "Standard Estimating" only contains the average productivity data of the construction industry, and it is difficult to predict the time and cost of any particular project; hence, there are some errors in estimating duration and cost for individual activity and project. To address these issues, this research collects data, measures productivity, and develops time and cost data using labor productivity based on field conditions from the collected data. A probabilistic approach is also proposed to develop data. A case study is performed to validate this process using actual data collected from construction sites and it is possible that the result will be used as the EVMS baseline of cost management and schedule management.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.1
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• pp.1-8
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• 2024

This study analyzed the impact of Higher-order resources on profit sustainability for domestic companies using a mathematical statistical model. Higher-order resources refer to resources that do not directly affect profits but influence other resources that directly contribute to profits. As a result of analysis using 30 years of actual data from more than 650 domestic companies, the average duration of competitive advantage including high-order resources was found to be about twice as long as the period suggested by the autoregressive model excluding high-order resources. Through this, if companies want to earn more profits over a long period of time than their competitors, they must not only possess resources that are more valuable, rare, difficult to imitate, and non-substitutable compared to their competitors, but also that higher-order resources can contribute to changes in these resources over time. It was confirmed that it must lead the long-term profit difference. High-level resources include strategic planning, mergers and acquisitions (M&A) capabilities, and good forecasting.

• Journal of Korea Water Resources Association
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• v.56 no.10
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• pp.631-639
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• 2023

Flash drought (FD), characterized by the rapid onset and intensification, can significantly impact ecosystems and induce immediate water stress. A more comprehensive understanding of the causes and characteristics of FD events is required to enhance drought monitoring. Therefore, we investigated the FD events took place over the Korean peninsula using Global Land Data Assimilation System (GLDAS) data from 2012 to 2022. We first detected FD events using the stress-based method (Standardized Evaporative Stress Ratio, SESR), and analyzed the frequency and duration of FDs. The FD events were classified into three cases based on the variations in Actual Evapotranspiration (AET) and potential Evapotranspiration (PET), and spatially analyzed. Results revealed that there are regional disparities in frequency and duration of FDs, with a mean frequency of 6.4 and duration of 31 days. When classified into Case 1 (normal condition), Case 2 (AET-driven), and Case 3 (PET-driven), we found that Case 2 FDs emerged approximately 1.5 times more frequently than those driven by PET (Case 3) across the Korean peninsula. Case 2 FDs were found to be induced under water-limited conditions, and led both AET and PET to be decreased. Conversely, Case 3 FDs occurred under energy-limited conditions, with increase in both. Case 2 FDs predominantly affected the northwestern and central-southern agricultural regions, while Case 3 occurred in the eastern region, characterized by forested land cover. These findings offers insights into our understanding of FDs over the Korean peninsula, considering climate factors, land cover, and water availability.

• Journal of Preventive Medicine and Public Health
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• v.24 no.1 s.33
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• pp.37-44
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• 1991

In the plywood manufacturing factory established in 1979, female 3 workers who had exposed to adhesives containing formaldehyde for more than 48 months of duration suffered from eye, nasal, oral, throat and skin irritation and dyspnea as chief complaints. The actual level of the exposure to formaldehyde were not estimated when the exposed workers started to have above symptoms. The environmental monitoring of workplace was measured on April 25, 1990, and the concentration of formaldehyde revealed 0.2 ppm, however the exhaustive ventilatory system was already installed at that time. Twenty six subjects from entire factory were examined by questionnaire, physical examination and spirometry, etc. on August 22, 1990. Significant difference was observed in symptoms and signs of nasal, oral and throat irritation between the exposed group with longer duration and that with short duration. When the exposed group with longer duration was compared to the group of nonexposed, symptoms and signs of nasal, oral, throat and skin irritaion, chest tightness and dullness were significantly increased in the former group. The results of the spirometric test showed that the forced vital capacity and the forced expiratory volume at 1 second were decreased among the exposed group with longer duration but not significant.

• Korean Journal of Community Nutrition
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• v.15 no.1
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• pp.137-148
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• 2010

This study was conducted on 175 child-care teachers, who participated in in-service education, to research the methods to improve child-care teacher's nutrition management capability for infants and children. Investigated results of child-care teachers' nutrition knowledge, dietary attitude status, and needs on nutrition education in child-care centers are as follows: The score of child-care teachers' nutrition knowledge was 10.83 points out of 15, which is about 72%. Total score increased as teachers' age but not significantly different from their career duration, since teachers who have a child-care career less than 5 years acquired 10.91 points, which is higher than 10.64 points of teachers having more than 5 years of child-care career. Teachers' average recognition to the nutrition knowledge was 90.6%, increased significantly by the older they are, and decreased according to the accumulation of their career. The average accuracy of the nutrition knowledge was 79.7%, increased in proportion to the teachers' age. The marks of child-care teachers' dietary attitude were 41.3 points (possible score range 5-50) and 83%, older teachers tended to have more desirable dietary attitude. As indicated by the increment of child-care career, the score of emotional attitude tended to be increased but which of cognitive and behavioral attitude showed a declining tendency. Nutrition information which child-care teachers were mainly interested in were correct selection of food (58.1%), obesity and weight management (52.7%), and nutrient content of food (44.9%). Nutrition education contents which child-care teachers needed were 'nutritious food and menu for child' (72.2%), 'health management of child' (69.2%) and meal management of child (40.2%). Nutrition education methods, which child-care teachers considered as of desirable ones, were cooking class of small scale (31.8%), visiting class at child-care center (26.5%). In consequence, the nutrition knowledge and dietary attitude of child-care teachers were not good and showed different issues by age and career duration. Therefore, it is requisite to intensify nutrition management courses in child-care teachers' qualification and in-service education courses which has actual necessity and suitability based on teachers' age, career, and the type of child-care center, and to disseminate these through public health centers and child-care & education information centers to pursue the efficient balance of nutrition education programs.

• Journal of Preventive Medicine and Public Health
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• v.21 no.1 s.23
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• pp.89-98
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• 1988

While there have been not a few reports on the seroepidemiological characteristics of hepatitis B virus (HBV) infection in Korea, most of them, however, have had several limitations; operational definition of HBV infection, validity of detection methods of HBV serologic markers, size of the study population, and confirmation of the vaccination history against HBV, etc. In order to avoid such limitations, authors randomly selected 1,495 healthy adults among the 217,511 insured (target population) of Korean Medical Insurance Corporation, living in seoul, and tested HBV serologic markers by RIA method and conducted direct interview to them. Although HBV serologic markers (HBsAg, anti-HBs and anti-HBc) of all the subjects were tested, 392(26.2%) of interview failure cases and 361 vaccinee were excluded from the actual population. Finally, the serologic markers tested of 742 nonvaccinee (study population) only were analysed for the seroepidemiologic observation of the natural infection of HBV. The seroepidemiological characteristics of HBV infection in Korea were as follows ; 1. Point prevalence of HBs antigenemia was 11.7(9.1{\sim}14.3)% in male, which was slightly higher than that of female, 9.5($3.7{\sim}15.3$)%. This level was one of the highest among those of Asian-Pacific countries. Decreasing tendency of HBsAg prevalence alter the age of 50 was observed, which seems to be due to selective attrition of HBV chronic carriers among the healthy adults and/or to the limited-lasting duration of the HBs antigenemia, in part. 2. Point prevalence of anti-HBc(78.8% in male,50.9% in female) was higher than that of anti-HBs(65.2% in male,46.6% in female), respectively. And both of them were higher in male than in female. Increasing tendency of the prevalence of both antibodies was observed by age, which seems to be largely due to recurrent infection in adults and to some cumulative effect, in part, of their relatively longer-lasting duration. 3. The level of HBV infection defined by positive for at least one of the 3 serologic markers of HBV by RIA method was 84.7($81.8{\sim}87.6$)% in male and 61.2($51.9{\sim}70.5$)% in female, which was also one of the highest among those of Asian-Pacific countries. The proportion of susceptible population to HBV infection among healthy adults was 15.3% in male and 38.8% in female. 4. The relative frequency of current or past infection and chronic carrier among HBV infected person was estimated. The currently or past infected was estimated 75.7% in male and 71.8% in female, and chronic carrier state, 13.8% in male and 14.1% in female. The analysis of the geometric mean of the antibody titer in anti-HBs positive sera indicated also to be compatible with the above findings, suggesting that active, even though inapparent, infection of HBV occur so frequently among healthy adults in Korea.

• Journal of the Korean earth science society
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• v.38 no.6
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• pp.395-404
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• 2017

In this study, we classified observed fog events in the Middle Nakdong River near Gumi and analyzed the meteorological characteristics before and after the fog formation. The observation was performed from 2013 to 2015 using visibility meter. A total of 74 fog events were observed and most of them were classified as steam fog. The duration of observed steam fogs was longer than that of typical inland fogs because the nocturnal evaporation from the water surface was enhanced by the topographical characteristics. In order to analyze the effect of evaporation from the stream on the fog duration, the evaporation was estimated using the Penman-Monteith and the Bulk aerodynamic methods. The estimated evaporation by the Bulk method was similar to the actual evaporation from the water surface. Therefore, the Bulk method is suitable for estimating the evaporation from water surface. The evaporation amount, estimated by using the Bulk method was higher on fog days than non-fog days at 06 LST and 07 LST. The added evaporation of fog days released latent heat to the atmosphere and provided energy to maintain the turbulence in the fog. This phenomenon was confirmed by the increase of wind speed, temperature and turbulent kinetic energy within the fog.

• Journal of Korean Physical Therapy Science
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• v.4 no.2
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• pp.421-432
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• 1997

To find out the actual status of treatment of physically handicapped who were stayed of home, 320 physically handicapped persons were selected among total 6,264 physically handicapped registered in Taejon city, surveyed from January 1st to March 30, 1997. Following are the results ana lysed of collected data from 201 samped persons. 1. For the cause of physically handicapped, 36.3% was congenital, 26.9% was cerebralvascular acciednt(CVA). and 14.9% was infectious diseases and others in that orders. The must frequest cause of below 20 years age group was congenital cause, but that of $20{\sim}30$ years age group and $40{\sim}50$ years age group were accident and CVA repectively. 30.0% of respondents caused by infection and others earned household living expenses. Household living expenses were higher among the respondents caused by congenital cause but those were lowest in the accidental couse group. Handicap durations were longer in the accidental cause group and infections and others group than the congenital cause group and CVA group. 2. 54.7% of studied handicapped were under treatment. But 36.3% of them were stopped treatment, and 8.9 % of them answered not treated. Most handicapped, coused by congenital and CAV, were under treatment, but most of them caused by accidental and others were stopped treatment. 3. For the medical facilities, 54.5% of them utilized welfare facility, but 25.5% utilized general hospital and 20.0% of them utilized oriental medical hospital and health centers. Congenital cause group frequently selected welfare facility for the treatment facility. But accidental cause group frequently seleced general hospitals and CVA gruop frequently selected oriental medical hospital and others. The medical cost of welfare facility, oriental medical hospitals and others were lower than that of general hospitals. 4. The proportions of under treatment were higher among yonger age higher monthly living expenses group shorter handicapped duration groups, congenital cause group and handicap grade II group. But that of stop treatment were higher among congenital cause group, infectious and others cause group, and handicap grade I & then III group. 5. For the feelings satisfacion about medical treatment, only 35.3% of under treated group responed satisfation. 55.5% of them responded so-so, but 9.1 % responed dissatisfaction. The proportion of satisfaction was higher among shorter handicap duration group.

• Journal of Korea Water Resources Association
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• v.51 no.3
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• pp.263-272
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• 2018

For the design of hydraulic structures, the design flood discharge corresponding to a specific frequency is generally used by using the design storm calculated according to the rainfall-runoff relationship. In the past, empirical equations such as rational equations were used to calculate the peak flow rate. However, as the duration of rainfall is prolonged, the outflow patterns are different from the actual events, so the accuracy of the temporal distribution of the probability rainfall becomes important. In the present work, Huff's quartile method is used for the temporal distribution of rainfall, and the third quartile is generally used. The regression equation for Huff's quadratic curve applies a sixth order polynomial equation because of its high accuracy throughout the duration of rainfall. However, in statistical modeling, the regression equation needs to be concise in accordance with the principle of simplicity, and it is necessary to determine the regression coefficient based on the statistical significance level. Therefore, in this study, the statistical significance test for regression equation for temporal distribution of the Huff's quartile method, which is used as the temporal distribution method of design rainfall, is conducted for 69 rainfall observation stations under the jurisdiction of the Korea Meteorological Administration. It is statistically significant that the regression equation of the Huff's quartile method can be considered only up to the 4th order polynomial equation, as the regression coefficient is significant in most of the 69 rainfall observation stations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.615-623
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• 2016

This study was conducted to identify differences between qualities of health related to quality of life according to the general characteristics of ankylosing spondylitis patients. Overall, 275 patients who were older than 19 years, drug-maintained for over 4 weeks from Jan 13th to Feb 12th and diagnosed as ankylosing spondylitis at C university hospital participated in this study. Collected data were analyzed through descriptive statistics, t-tests, ANOVA, Scheffe's-test and multiple regression. The results of the present study revealed that Age (p=.008), Job (p<0.001), Number of comorbidity (p<0.001), Surgery for Ankylosing Spondylitis (p=0.002), Disease duration after onset symptom (p=0.010), Disease duration after diagnosis (p=0.027), Alcohol drinking (p=0.002) and Erythrocyte sedimentation rate (p=0.049) were meaningful factors to the quality of health-related life for ankylosing spondylitis patients, and multiple regression analysis showed that level of education, income, comorbidity and alcohol consumption was a significant variable. In conclusion, the results of this study indicated that, to improve quality of life, arbitration programs for improving general characteristics and considering demographic social characteristics and clinical features need to be provided. Therefore, it is expected that the results of this study would be used as actual grounds to develop integrated arbitration programs.