• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.4
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• pp.25-34
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• 2010

This study was conducted to develop evaluation indicators to improve athletic performance and operational management of golf courses and the results of the research are as follows. Through theoretical research and a preliminary professional survey, 15 on-going evaluations of golf course composition and operational management and 55 sub-evaluation indices were rejected while 10 on-going evaluations and 52 sub-evaluation indicators were reconfigured as final for environmental-friendliness, level of member services, level of human service of game personnel, difficulties of course, management level of the course, fairness of operational management, accessibility and location characteristic, traditions and ambiance of the golf club, quality of course, and course layout. When analyzing the important decision factors in golf course user preference evaluation indicators, the following contributed in the order of higher to lower contributions: the management level of the course, excellence of the course, level of human services for personnel, course layout and environmental-friendliness. When identifying the path coefficient of golf course evaluation indicators, the curvature of a hole and the length of the course had a causal effect on the 'course layout' section. Tournament facilities and various shot values had a causal relationship with 'excellence of the course', in the order of higher to lower, and convenience of waiting and fair allocation of reservations for 'fairness of operational management'. The history of the golf course and its environmental characteristics, history and culture of the region have relatively higher causal effects on 'traditions of the golf club' and geographical conditions on 'accessibility and location characteristics', pesticide and fertilizer usage and water pollution on 'environmental-friendliness', and member benefit and kindness of employees on 'level of member services'. The kindness and expertise of the game personnel had a relatively higher causal effect on the 'level of human services of game personnel', the location of tenning area, and location of OB and hazards on 'difficulties of course', and rough conditions and obstacles management on 'management level of the course'. There is a need to complete a systematic evaluation index system for golf course user preferences through future studies for a more detailed assessment, as well as a process to verify these evaluation indicators by application to domestic and international golf courses.

• Safety and Health at Work
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• v.12 no.4
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• pp.462-470
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• 2021

Background: Fatigue is pervasive, under-reported, and potentially deadly where flight operations are concerned. The aviation industry appears to lack a standardized, practical, and easily replicable protocol for fatigue risk assessment which can be consistently applied across operators. Aim: Our paper sought to present a framework, supported by real-world data with subjective and objective parameters, to monitor aircrew fatigue and performance, and to determine the safe crew configuration for commercial airline operations. Methods: Our protocol identified risk factors for fatigue-induced performance degradation as triggers for fatigue risk and performance assessment. Using both subjective and objective measurements of sleep, fatigue, and performance in the form of instruments such as the Karolinska Sleepiness Scale, Samn-Perelli Crew Status Check, Psychomotor Vigilance Task, sleep logs, and a wearable actigraph for sleep log correlation and sleep duration and quality charting, a workflow flagging fatigue-prone flight operations for risk mitigation was developed and trialed. Results: In an operational study aimed at occupational assessment of fatigue and performance in airline pilots on a three-men crew versus a four-men crew for a long-haul flight, we affirmed the technical feasibility of our proposed framework and approach, the validity of the battery of assessment instruments, and the meaningful interpretation of fatigue and work performance indicators to enable the formulation of safe work recommendations. Conclusion: A standardized occupational assessment protocol like ours is useful to achieve consistency and objectivity in the occupational assessment of fatigue and work performance.

• Journal of Digital Convergence
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• v.20 no.1
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• pp.107-117
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• 2022

This study aims to examine the relationship between the economic, environmental and social activities of sustainable supply chains and the customer satisfaction and customer retention rate, which are the final results in the supplier's operational performance and the buyer's market performance. The survey was conducted on employees in charge of supply chain management, purchasing company, partner company, and logistics management in the company. The final 193 valid data were analyzed to verify the research hypothesis. The results of the study showed that the economic and social activities of the sustainable supply chain had a positive effect on the supplier performance and the purchaser performance, but environmental activities had a negative effect on the supplier performance. In addition, the purchasing company performance has a positive effect on customer satisfaction and customer retention rate. This study provides a theoretical basis for sustainable supply chain activities to affect the operating performance of suppliers and the market performance of buyers, and suggests implications for enhancing the competitiveness of companies through the performance creation process that affects customer performance.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.4
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• pp.20-29
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• 2022

The operational modal analysis (OMA) technique, which extracts the modal parameters of a structural system using ambient vibrations, has been actively developed as a field of structural health monitoring of cable-supported bridges. In this paper, the short and long-term modal parameters of a cable-stayed bridge were evaluated using the acceleration data obtained from the two ambient vibration tests (AVTs) and three years of continuous measurements. A total of 27 vertical modes and 1 lateral mode in the range 0.1 ~ 2.5 Hz were extracted from the high-resolution AVTs which were conducted in the 6th and 19th years after its completion. Existing OMA methods such as Peak-Picking (PP), Eigensystem Realization Algorithm with Data Correlation (ERADC), Frequency Domain Decomposition (FDD) and Time Domain Decomposition (TDD) were applied for modal parameters extraction, and it was confirmed that there was no significant difference between the applied methods. From the correlation analysis between long-term natural frequencies and environmental factors, it was confirmed that temperature change is the dominant factor influencing natural frequency fluctuations. It was revealed that the decreased natural frequencies of the bridge were not due to changes in structural performance and integrity, but to the environmental effects caused by the temperature difference between the two AVTs. In addition, when the TDD technique is applied, the accuracy of extracted mode shapes is improved by adding a proposed algorithm that normalizes the sequence so that the autocorrelations at zero lag equal 1.

• Environmental Engineering Research
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• v.25 no.2
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• pp.243-250
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• 2020

A down-flow hanging sponge (DHS) bioreactor was operated for the treatment of domestic wastewater. The Stover-Kincannon model was applied for kinetic evaluation of the reactor performance during the operational period. As a result, the coefficient of determination (R²) for straight lines of effluent concentration from the experimental data and from the predictive data of BOD₅; NH₄⁺-N; and TN were 0.9727; 0.9883; and 0.9934, respectively. The calculation of saturation value constant (Umax - g L^-1 d^-1) and maximum utilization rate constant (KB - g L-1 d-1) were 56.818 and 75.034 for BOD₅; 2.960 and 4.713 for NH₄⁺-N; 2.810 and 8.37 for TN, respectively. The study suggests that Stover-Kincannon model can be used for effective evaluation of kinetic removal of BOD₅; NH₄⁺-N; and TN from domestic wastewater treated in a DHS bioreactor.

• Journal of Environmental Science International
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• v.25 no.4
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• pp.603-613
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• 2016

Fog may have a significant impact on road conditions. In an attempt to improve fog predictability in Jeju, we conducted machine learning with various data mining techniques such as tree models, conditional inference tree, random forest, multinomial logistic regression, neural network and support vector machine. To validate machine learning models, the results from the simulation was compared with the fog data observed over Jeju(184 ASOS site) and Gosan(185 ASOS site). Predictive rates proposed by six data mining methods are all above 92% at two regions. Additionally, we validated the performance of machine learning models with WRF (weather research and forecasting) model meteorological outputs. We found that it is still not good enough for operational fog forecast. According to the model assesment by metrics from confusion matrix, it can be seen that the fog prediction using neural network is the most effective method.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.3
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• pp.173-179
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• 2012

The purpose of this paper is to examine the effects on reliability of equipment or product which spends a great deal of its time in the dormant condition. Many systems experienced periods of dormancy throughout their life cycle, such as periods of operational storage where the system waits, ready for use. The design of such systems must account for how these period of dormant effects system performance. The methodology for predict and analysis was developed to support the evaluation of dormant modes of operation of systems and subsystems. For proper handling of the dormant environment, issues relating to dormant failures need to be taken into consideration from design stage of the lifecycle. Furthermore, the relevant environmental concerns that need to be taken into consideration depend on the environmental factors associated with each different target environment. This paper will look at dormant reliability, the possible dormant reliability models and the methodology on life cycle reliability which has different dormant phase.

• Membrane and Water Treatment
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• v.6 no.1
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• pp.53-75
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• 2015

This paper provides an overview of the role of membranes in bioelectrochemical systems (BESs). Bioelectrochemical systems harvest clean energy from waste organic sources by employing indigenous exoelectrogenic bacteria. This energy is extracted in the form of bioelectricity or valuable biofuels such as ethanol, methane, hydrogen, and hydrogen peroxide. Various types of membranes were applied in these systems, the most common membrane being the cation exchange membrane. In this paper, we discuss three major bioelectrochemical technology research areas namely microbial fuel cells (MFCs), microbial electrolysis cells (MECs) and microbial desalination cells (MDCs). The operation principles of these BESs, role of membranes in these systems and various factors that affect their performance and economics are discussed in detail. Among the three technologies, the MFCs may be functional with or without membranes as separators while the MECs and MDCs require membrane separators. The preliminary economic analysis shows that the capital and operational costs for BESs will significantly decrease in the future due mainly to differences in membrane costs. Currently, MECs appear to be cost-competitive and energy-yielding technology followed by MFCs. Future research endeavors should focus on maximizing the process benefits while simultaneously minimizing the membrane costs related to fouling, maintenance and replacement.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.566-571
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• 2006

A sequencing batch biofilm reactor (SBBR) operated with a cycle of anaerobic - aerobic - anoxic - aerobic has been evaluated for the nutrient removal characteristics. The sponge-like moving media was filled to about 10% of reactor volume. The sewage was the major substrate while external synthetic carbon substrate was added to the anoxic stage to enhance the nitrogen removal. The operational results indicated that maximum T-N and T-P removal efficiencies were 97% and 94%, respectively were achieved, while COD removal of 92%. The observations of significant nitrogen removal in the first aerobic stage indicated that nitrogen removal behaviour in this SBBR was different to conventional SBR. Although the reasons for aerobic nitrogen removal has speculated to either simultaneous nitrification and denitrification or anoxic denitrification inside of the media, further researches are required to confirm the observation. The specific oxygen uptake rate (SOUR) test with biofilm and suspended growth sludge indicated that biofilm in SBBR played a major role to remove substrates.

• Journal of Drive and Control
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• v.20 no.3
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• pp.1-8
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• 2023

The purpose of this study was to investigate and compare the impact of engine load on the emission characteristics of excavator engines, with the aim of improving the method for calculating the emission inventory of construction machinery. The engine load in excavators is directly correlated with the operational workload, and variations in the load factor (LF) can significantly influence the emission inventory. Thus, on-board diagnostic (OBD) data from an excavator at a construction site were systematically collected to measure engine output and emissions. The results revealed discernible differences in emissions based on engine load, even when the average excavator engine performance remained constant. This highlights the significant influence of the type and characteristics of the work being carried out on emission characteristics. Making realistic adjustments to the LF used in emission calculation formulas emerges as a crucial strategy for environmental improvement. Moreover, the analysis of the effects of engine load on emissions from excavators provides valuable insights for enhancing environmental protection measures.