• Journal of Korea Water Resources Association
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• v.30 no.5
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• pp.423-430
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• 1997

It is one of the most important factors to determine the effective rainfall for estimation of flood hydrograph in design schedule. SCS curve number (CN) method has been frequently used to estimate the effective rainfall of synthesized design flood hydrograph for hydraulic structures. But, it should be cautious to apply SCS-CN originally developed in U.S.A to watersheds in Korea, because characteristics of watersheds in Korea and cropping patterns especially like a paddy land cultivation are quite different from those in USA. New CN method has been introduced. Maximum storage capacity which was herein defined as Umax can be calibrated from the streamflow data and converted to new CN-I of direst condition of soil moisture in the given watershed. Effective rainfall for design flood hydrograph can be estimated by the curve number developed in the watersheds in Korea.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.6
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• pp.73-79
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• 2019

Continuous and tremendous data (canopy temperature and meteorological variables) are necessary to determine Crop Water Stress Index (CWSI). This study investigated the optimal monitoring time and interval of canopy temperature and meteorological variables (air temperature, relative humidity, solar radiation and wind speed) to determine CWSIs. The Nash-Sutcliffe model efficiency coefficient (NSE) was used to quantitatively describe the accuracy of sampling method depending upon various time intervals (t=5, 10, 15, 20, 30 and 60 minutes) and CWSIs per every minute were used as a reference. The NSE coefficient of wind speed was 0.516 at the sampling time of 60 minutes, while the ones of other meteorological variables and canopy temperature were greater than 0.8. The pattern of daily CWSIs increased from 8:00 am, reached the maximum value at 12:00 pm, then decreased after 2:00 pm. The statistical analysis showed that the data collection at 11:40 am produced the closest CWSI value to the daily average of CWSI, which indicates that just one time of measurement could be representative throughout the day. Overall, the findings of this study contributes to the economical and convenient method of quantifying CWSIs and irrigation management.

• Journal of KIBIM
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• v.9 no.3
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• pp.41-53
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• 2019

As a central part in smart construction, BIM has been rapidly spread in construction industry at large. However, the level of applying BIM in construction stage is still relatively lower than that in design stage due to unclear application method, inadequate design BIM model, technical faults of BIM itself, etc. Under these circumstances, public owners inevitably need to adjust the scope and pace in BIM application considering their internal support and capabilities of contractors. This study aims to suggest major BIM-applicable tasks during construction stage in the process of establishing gradual long-term and short-term introduction strategy for public apartment housing projects. Those major tasks were identified with the combination of the importance of tasks and the future benefits of BIM using IPA method. To do so, the degrees of contribution to achieving objectives in construction, current task execution, and communication requirement were investigated by internal site managers. On the other hand, the expected benefits and current level of using BIM were assessed by BIM experts. Among operational tasks by phases, design review, construction plan review, making as-built drawing, etc. were categorized as major tasks. In addition, progress control, regular meeting, master schedule development, work inspection, on-site quality check, etc. were also drawn as major tasks by management areas. The results of this study will provide the useful reference for owners concerned about the introduction of new technologies.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.4
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• pp.159-167
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• 2015

We consider a wafer lot transfer/release planning problem from semiconductor wafer fabrication facilities to probing facilities with the objective of minimizing the deviation of workload and total tardiness of customers' orders. Due to the complexity of the considered problem, we propose a two-level hierarchical production planning method for the lot transfer problem between two parallel facilities to obtain an executable production plan and schedule. In the higher level, the solution for the reduced mathematical model with Lagrangian relaxation method can be regarded as a coarse good lot transfer/release plan with daily time bucket, and discrete-event simulation is performed to obtain detailed lot processing schedules at the machines with a priority-rule-based scheduling method and the lot transfer/release plan is evaluated in the lower level. To evaluate the performance of the suggested planning method, we provide computational tests on the problems obtained from a set of real data and additional test scenarios in which the several levels of variations are added in the customers' demands. Results of computational tests showed that the proposed lot transfer/planning architecture generates executable plans within acceptable computational time in the real factories and the total tardiness of orders can be reduced more effectively by using more sophisticated lot transfer methods, such as considering the due date and ready times of lots associated the same order with the mathematical formulation. The proposed method may be implemented for the problem of job assignment in back-end process such as the assignment of chips to be tested from assembly facilities to final test facilities. Also, the proposed method can be improved by considering the sequence dependent setup in the probing facilities.

• Journal of the Korea Society of Computer and Information
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• v.25 no.6
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• pp.119-129
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• 2020

Software development activities are influenced by stochastic theory rather than deterministic one due to having process variability. Stochastic methods factor in the uncertainties associated with project activities and provides insight into the expected project outputs as probability distributions rather than as deterministic approximations. Thus, successful software projects systematically manage and balance five objectives based on historical probability: scope, size, cost, effort, schedule, and quality. Although software size estimation having much uncertainty in initial development has traditionally performed using deterministic methods: LOC(Lines Of Code), COCOMO(COnsructive COst MOdel), FP(Function Point), SLIM(Software LIfecycle Management). This research aims to present a function point method based on stochastic distribution and a case study based on Monte Carlo Simulation applying on an automotive electrical and electronics system software development. It is expected that the result of this paper is used as guidance for establishing of function point method in organizations and tools for helping project managers make decisions correctly.

• Safety and Health at Work
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• v.12 no.3
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• pp.390-395
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• 2021

Background: Health-care providers typically undergo shift work and are subjected to increased stress. Night shift work may induce disturbed sleep cycles and circadian rhythm. The objective of this study was to explore if night shift workers (NSWs) show an increased risk of abnormal thyroid-stimulating hormone (TSH). Methods: We conducted a retrospective cohort study of 574 employees without thyroid disease and abnormal TSH at baseline who underwent annual check-ups between 2007 and 2016 in a medical center. NSWs were defined as those with working time schedules other than daytime hours. We calculated the incidence rate and estimated the adjusted hazard ratio (HR) for incident abnormal TSH and subclinical hypothyroidism compared with non-NSWs using a Cox regression model. Results: A total of 56 incident abnormal TSH cases and 39 subclinical hypothyroidism cases in NSWs were identified during 3000 person-years of follow-up. In models adjusted for age, sex, obesity, and working departments, we found no increased relative risk for incident abnormal TSH (HR: 0.72, 95% confidence interval: 0.33-1.60) or subclinical hypothyroidism (HR: 0.52, 95% confidence interval: 0.19-1.45) when comparing NSWs to non-NSWs; nor were incidence rates significantly different among exclusively medical employees after excluding administrative staff. Conclusion: In this hospital-based nine-year follow-up retrospective cohort study, NSWs were not associated with increased relative risk of incident abnormal TSH and subclinical hypothyroidism, in contrast to previous cross-sectional studies.

• The Korean Journal of Archival Studies
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• no.58
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• pp.299-332
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• 2018

The purpose of this study is to investigate the current status and causes of misclassification of school records and to suggest the directions to improve the School Records Management Criteria Table(general disposition authority for school records), which will lead to misclassification reducement. This study begins with analysing the records created or received in four schools sampled for one year to investigate the status and causes of misclassifications. A advisory group including four administrative officers and seven records managers was formed and group meeting was held twice to identify the causes of the misclassification and to suggest alternatives. In this study, 33 unit tasks(transactions) with frequent misclassification were identified, and the cause of misclassification was analyzed based on focus group interviews. The main causes of misclassification were categorized into two types. This study concludes with suggesting the improvement of the School Records Management Criteria Table for addressing the causes, including commentary reinforcement and the addition of workflow to complex tasks.

• Health Policy and Management
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• v.31 no.2
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• pp.173-179
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• 2021

Background: In Korea, the length of stay and medical expenses incurred by medical aid patients are increasing at a rate faster than the national health insurance. Therefore, there is a need to create a management strategy for each type of hospitalization to manage the length of stay of medical aid patients. Methods: The study used data from the 2019 National Health Insurance Claims. We analyzed the factors that affect the length of stay for 186,576 medical aid patients who were hospitalized for more than 31 days, with a focus on the type of hospitalization in long-term care hospitals. Results: The study found a significant correlation between gender, age, medical aid type, chronic disease ratio, long-term care hospital patient classification, and hospitalization type variables as factors that affect the length of hospital stay. The analysis of the differences in the length of stay for each type of hospitalization showed that the average length of stay is 291.4 days for type 1, 192.9 days for type 2, and 157.0 days for type 3, and that the difference is significant (p<0.0001). When type 3 was 0, type 1 significantly increased by 99.4 days, and type 2 by 36.6 days (p<0.0001). Conclusion: A model that can comprehensively view factors, such as provider factors and institutional factors, needs to be designed. In addition, to reduce long stays for medical aid patients, a mechanism to establish an early discharge plan should be prepared and concerns about underutilization should be simultaneously addressed.

• International Journal of Computer Science & Network Security
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• v.21 no.1
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• pp.137-142
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• 2021

The Internet of Things (IoT) paradigm is at the forefront of present and future research activities. The huge amount of sensing data from IoT devices needing to be processed is increasing dramatically in volume, variety, and velocity. In response, cloud computing was involved in handling the challenges of collecting, storing, and processing jobs. The fog computing technology is a model that is used to support cloud computing by implementing pre-processing jobs close to the end-user for realizing low latency, less power consumption in the cloud side, and high scalability. However, it may be that some resources in fog computing networks are not suitable for some kind of jobs, or the number of requests increases outside capacity. So, it is more efficient to decrease sending jobs to the cloud. Hence some other fog resources are idle, and it is better to be federated rather than forwarding them to the cloud server. Obviously, this issue affects the performance of the fog environment when dealing with big data applications or applications that are sensitive to time processing. This research aims to build a fog topology job scheduling (FTJS) to schedule the incoming jobs which are generated from the IoT devices and discover all available fog nodes with their capabilities. Also, the fog topology job placement algorithm is introduced to deploy jobs into appropriate resources in the network effectively. Finally, by comparing our result with the state-of-art first come first serve (FCFS) scheduling technique, the overall execution time is reduced significantly by approximately 20%, the energy consumption in the cloud side is reduced by 18%.

• Journal of Oriental Neuropsychiatry
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• v.33 no.3
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• pp.259-266
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• 2022

Objectives: The combination of Harm-Avoidance (HA) and Self-Directedness (SD) of Temperament and Character Inventory (TCI) has been reported pivotal for mental health; however its clinical usefulness in integrative medicine has not sufficiently reported. The purpose of this study was to illustrate multi-phasic mental health of subjective satisfaction with life, emotional well-being, and psychopathology, following the HA-SD profile groups. Methods: A total of 527 Korean university students reported HA and SD scores as to render their HA-SD profile, and multi-phasic mental health characteristics using Satisfaction with Life Scale (SWLS), Positive Affect and Negative Affect Schedule (PANAS), and Beck Depression Inventory (BDI) with composite well-being scales of SC (Sum of Self-Directedness and Cooperativeness score) and HI (Happiness Index, subtraction of Negative Affect (NA) score from Positive Affect (PA) score) as standardized. Pearson's correlation was used to report correlation coefficient, and the ANCOVA with age and sex as covariates, to show significant differences in mental health and well-being between the HA-SD profile groups. Results: The HA-SD profile groups showed distinctive multi-phasic mental health characteristics; health related scores of SWLS, PA, SC and HI decreased following the order of hS (low HA and high SD), HS (high HA and high SD), hs (low HA and low SD) and Hs (high HA and low SD) profile groups; however the non-health related scores of NA and BDI showed contrasting order. Conclusions: The HA-SD profile was found to be clinically useful for examining multi-phasic mental health and well-being status, and the TCI may be an imperative personality inventory for integrative medicine.