• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.1
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• pp.231-243
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• 1994

A stochastic programming model for river water quality management was developed. River water quality, river flow, quality and flowrate of the wastewater treatment plant inflow were treated as random variables in the model. Withdrawal for water supply and submerged weir reaeration were included in the model itself. A probabilistic model was formulated to compute the expectation and variance of water quality using Streeter-Phelps equation. Chance constraints of the optimization problem were converted to deterministic equivalents by chance constrained method. Objective function was total annual treatment cost of all wastewater treatment plants in the region. Construction cost function and O & M cost function were derived in the form of nonlinear equations that are functions of treatment efficiency and capacity of treatment plant. The optimization problem was solved by nonlinear programming. This model was applied to the lower Han River. The results show that the reliability to meet the DO standards of the year 1996 is about 50% when the treatment level of four wastewater treatment plants in Seoul is secondary treatment, and BOD load from the tributary inflows is the same as present time. And when BOD load from Tanchon, Jungrangchon, and Anyangchon is decreased to 50%, the reliability to meet the DO standards of the year 1996 is above 60%. This results indicated that for the sake of the water quality conservation of the lower Han River, water quality of the tributaries must be improved, and at least secondary level of treatment is required in the wastewater treatment plants.

• Journal of agricultural medicine and community health
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• v.42 no.2
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• pp.57-68
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• 2017

Objectives: This study was performed to build the predictive model of suicidal ideation of elderly men living alone. Methods: As for the subject, 251 subjects suitable for the selection criteria were selected among elderly men living alone above 65 years old in one region in Gyeongnam and three regions in Gyeongbuk. The data were collected via questionnaires and analyzed using SPSS version 20.0 and Amos version 18.0. Results: The goodness-of-fit test result of hypothetical model were suitable for recommended level: ${\chi}^2/df=1.47$, RMR=.04, GFI=.92, AGFI=.90, CFI=.95, IFI=.95, RMSEA=.04. Self-esteem, individual coping, family cohesion, social support, social activity, and depression explained 55% of the model of suicidal ideation. The most influential direct factor of suicidal ideation was self-esteem, and social isolation was the most influential indirect influence on suicidal ideation. Conclusion: To sum up the above results, if we promote the researched variables of self-esteem, family cohesion, social activity, individual coping and social support in addition to developing and utilizing an efficient customized suicidal prevention nursing intervention program thereby reducing depression and social isolation, suicidal ideation of elderly men living alone would be prevented.

• Korean Journal of Culture and Social Issue
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• v.25 no.4
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• pp.353-375
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• 2019

The purpose of this study was to examine the validity and reliability of the Playfulness Scale for Adults. The Korean version of the Playfulness Scale for adults was developed by Proyer, R.T (2017) to measure the playfulness of adults. To validate the OLIW in Korean, item translation, back-translation, item analysis, and exploratory factor analysis (EFA) were conducted with 406 adults in study 1. Of the results obtained from study1, three items and one factor (7 items) were discarded because they turned out to be improper. In addition, 4 factors that were not the same as the original scale were extracted. This was checked by conducting confirmatory factor analysis (CFA) with 336 adults in study 2. CFA supported the 4 factors structure and all 4 factors showed adequate internal consistency. To check the concurrent validity of the Korean adults playfulness scale, correlation analysis with the APS, SMAP, PSYA, and NEO Personality Assessment was conducted. It showed significant positive correlation to APS, SMAP, PSYA, and showed the similar patterns of correlation with the sub factors of NEO Personality Assessment. Adult playfulness is related to the participation frequency of leisure. In conclusion, the Korean version of the playfulness scale for adults is a valid measure of playfulness for adults in Korea. The implications, practical use and suggestions for future study were discussed.

• Journal of Cadastre & Land InformatiX
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• v.51 no.2
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• pp.125-139
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• 2021

Continuous subway line expansion over the years in Seoul metropolitan area has contributed to improved accessibility to public transport. Since public transport accessibility has a significant impact on housing decisions, quantitative analysis of correlation between housing prices and public transport accessibility is regarded as one of the most important factors for planning better housing policies. This study defines the reduction of traveling time resulted from the construction of new metro stations despite them not being the closest stations as 'Network Expansion Effect', and seeks to understand how the Network Expansion Effect impacts on housing prices. The study analyzes monthly rent data converted from upfront lump sum deposit, so called Jeonse in Korea, from 2012 to 2018, through 'A Modified Repeat Sales Model.' As a result, the effect of 'Network Expansion' on rental prices in Seoul has stronger during the period of 2017 to 2018 than the base period of 2012 to 2014, which suggests the 'Network Expansion' has a meaningful effect on rent. In addition, in comparison between the most and the least affected group of apartments by 'Network Expansion Effect', the most affected group has more price increase than the least affected group. These findings also indicate that different levels of 'Network Expansion Effect' have various influences on the value of residential real estate properties.

• Korean Journal of Construction Engineering and Management
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• v.7 no.5
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• pp.167-176
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• 2006

It was found that Korean Standard of Estimate which has been used as the only basis of cost estimate of public construction projects had some side effects such as jerry-build construction and over-estimation because it failed to reflect the current price and the state-of-the-art construction methods in a changing construction environment. Therefore, the government decided to gradually introduce historical construction cost into cost estimate of public construction projects from 2004. This paper presents analytic criteria and a process model for deducing more current and reasonable historical construction cost for contract items from not only previous contract prices but also all of the other bid prices that were not contracted. The procedure of estimating actual unit cost proposed in this paper focuses on the removal of abnormal values including strategically too low or high prices and the time correction. In addition, basic research is conducted for the correction of actual unit cost through the analysis of fluctuation of bid price depending on bidding types and rates of successful bid. It is anticipated that the effective use of the proposed process model for estimating actual unit cost would make the cost estimation more current and reasonable.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.54-59
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• 2007

Recently, Apartment Reconstruction Projects are performing only with the basis of profitability without establishing either certain criteria or standard guideline. In addition, the profitability information contained in a disposal plan tends to be considered as a fixed value, and it is frequently changeable because reconstruction projects have such a long time to complete and many participants with respective interests. As mentioned above, the new approach needs to be developed which covers the limitation of the unvaried one. Consequently, this study focuses on the probability approach considering not only variances that affect the profit, but the relationship between profit and risk, and then is modeling. This study is anticipated to improve the reliability and accuracy of expected value as well as apply to the decision making criteria quantitively about potentially hidden risks in that projects.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.1
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• pp.101-113
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• 2010

Recently actual rainfall pattern is decreasing rainy days and increasing in rainfall intensity and the frequency of flood occurrence is also increased. To consider recent situation, Engineers use deterministic methods like a PMP(Probable Maximum Precipitation). If design storm wouldn't occur, increasing of design criteria is extravagant. In addition, the biggest structure cause trouble with residents and environmental problem. And then it is necessary to study considering probability of rainfall parameter in each sub-basin for design of water structure. In this study, stochastic rainfall patterns are generated by using log-ratio method, Johnson system and multivariate Monte Carlo simulation. Using the stochastic rainfall patterns, hydrological analysis, hydraulic analysis and 2nd flooding analysis were performed based on GIS for their applicability. The results of simulations are similar to the actual damage area so the methodology of this study should be used about making a flood risk map or regidental shunting rout map against the region.

• Journal of Korean Society of Transportation
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• v.21 no.3
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• pp.47-56
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• 2003

Considering the high density developments along the major traffic corridors in Seoul, transit-oriented street designs will be a very effective to control traffic congestion along the corridors. For testing the effectiveness, we selected. for our case study, Kangnam Street, which is one of the most highly developed corridors in Seoul The traffic study on Kangnam street in 2000 shows that the daily average bus speed is 11.73km/h, which is 5km/h lower than the auto speed. The Central Bus Lane system was applied on the Kangnam street to test impact on bus speed as well as auto speed. Simulation results show that with Central Bus Lane have been improved the travel speeds of bus as well as auto on Kangnam street from 14.4km/hr to 35.0km/hr and from 25.1km/hr to 26.1km/hr, respectively. The bus market share increases about 6-8 percentages. Especially, 13.4% of bus users are increased for long-distance trips.

• Journal of Convergence for Information Technology
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• v.9 no.9
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• pp.219-228
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• 2019

The purpose of this study was to develop a tool to assess the job satisfaction of dental hygienists and to evaluate the validity and reliability of the dental hygienist. A total of 54 items were translated into 24 items through content validity and content analysis. The results of this study are as follows: overall satisfaction, income, patient relations, professional time, personal time, Practice Management, Delivery of Care and co-worker relations were classified by exploratory factor analysis. The fit of the model through confirmatory factor analysis generally met the criteria. As a result of the internal consistency test, Cronbach's ${\alpha}$ was found to be a reliable measure of measurement, with an overall satisfaction of 0.918, an income of 0.833, a patient relationship of 0.804, an occupational time of 0.675, a personal time of 0.939, a work practice of 0.739, The validity and reliability of the dental hygienist 's job satisfaction measurement tool were verified to be appropriate. It can be used to study the job satisfaction of dental hygienist in the future.

• Journal of Nutrition and Health
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• v.56 no.3
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• pp.247-263
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• 2023

Purpose: This study was conducted to update the Nutrition Quotient for Adolescents (NQ-A), which is used to assess the overall dietary quality and food behavior among Korean adolescents. Methods: The first 30 candidate items of the measurable eating behavior checklist were obtained based on a previous NQ-A checklist, the results of the seventh Korea National Health and Nutrition Examination Survey data, Korea Youth Risk Behavior Survey data, national nutrition policies and dietary guidelines, and literature reviews. A total of 100 middle and high school students residing in Seoul and Gyeonggi Province participated in a pilot study using the 25-item checklist. Factor analysis and frequency analysis were conducted to determine if the checklist items were organized properly and whether the responses to each item were distributed adequately, respectively. As a result, 22 checklist items were selected for the nationwide survey, which was applied to 1,000 adolescent subjects with stratified sampling from 6 metropolitan cities. The construct validity of the updated NQ-A 2021 was assessed using confirmatory factor analysis. Results: Twenty checklist items were determined for the final NQ-A 2021. The items were composed of three factors: balance (8 items), moderation (9 items), and practice (3 items). The standardized path coefficients were used as the weights of items to determine the nutrition quotients. NQ-A 2021 and 3-factor scores were calculated according to the weights of questionnaire items. The weight for each of the 3 factors was determined as follows: balance, 0.15; moderation, 0.30; and practice, 0.55. Conclusion: The updated NQ-A 2021 is a useful instrument for easily and quickly evaluating the dietary qualities and eating behaviors of Korean adolescents.