• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.1
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• pp.87-93
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• 2008

Seismic control performance of MR dampers, which have severe nonlinearity, varies with respect to the dynamic characteristics of an earthquake such as magnitude, frequency and duration. In this study, the effects of excitation characteristics on the equivalent linear system of a building structure with the MR damper are investigated through numerical analysis for artificial ground motions generated from different response spectrums. The equivalent damping ratio of the structure with the MR damper is calculated using Newmark and Hall's equations for ground motion amplification factors. It is found that the equivalent damping ratio of the structure with the MR damper is dependent on the ratio of the maximum friction force of the MR damper over excitation magnitude. Frequency contents of the earthquake ground motion affects the equivalent damping ratio of long-period structures considerably. Also, additional damping effect caused by interaction between the viscousity and friction of the MR damper is observed. Finally. response reduction factors for equivalent linear systems are proposed in order to improve accuracy in the prediction of the actual nonlinear response.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.103-109
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• 2013

Estimating the high tuber solids needs a simulation system on potato growth, and its development should be obtained by using agricultural elements which analyze the relationship between crop growth and agricultural factors. An accurate simulation to predict solids level against climatic change employs a calculation of in vivo energy consumption and bias for growth and induction shape in a slight environmental adaptation. So, to calculate in vivo energy consumption, this study took a concept of estimate of the amount of basal metabolism in each tuber. In the validation experiments, the results of measuring solid accumulation of potatoes harvested at dates suggested by simulation agreed with the actual measured values in each regional field during the growth period of years from 2006 till 2010. The mean values of tuber solids level and inter-annual level variation in validation experiments were predicted well by the simulation model. And also, the results of validation experiments represent that concentration of tuber solids were due mainly to the duration of sunshine, above 190 hours per a month, and the cumulative amount of radiation, above 2,200 $MJ{\cdot}m^{-2}$, of the effective growth period.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.5 s.143
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• pp.542-549
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• 2005

Naval ships are complex weapon systems which play the integrated performance by system integration of many kinds of weapon systems and their leading ships are usually not disposed after test and evaluation but militarised. Then, strict project management is required for naval ship building projects by identifying problems early and by taking prefer measures in time against unexpected situations encountered in the process of the projects. EVMS is a project management system which can manage the schedule and the budget of a project concurrently and estimate the project's time duration and the cost at project completion. In this paper, the applicability and usefulness of WMS is studied for a assumed navai ship building project, in the environment of monetary fluctuations such as price index, wage increase rate and exchange rate.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.11
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• pp.297-305
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• 2021

The study aims to investigate loyalty rewards programs on customers' satisfaction in Jordanian banks, and to investigate the statistical differences in loyalty rewards programs and customers' satisfaction according to demographics such as age, sex, education level, duration of engagement with bank, and the type of bank. The study is based on the data obtained from the sample. The questionnaire is the tool for collecting data from the respondents. The study materials include website resources, regular books, journals, and articles. The study population consists customers in the banking sector. The figures indicate that number of actual customers reaches 2.06 million. The sample size requirement is 386 items. Customers are split between traditional and Islamic banks, with 231 and 155 customers respectively. The stratified random sampling technique and the structural equations modeling methodology were used. The results show moderated impact of the loyalty rewards programs on customers' satisfaction. The results show statistical differences in the loyalty rewards programs and customers' satisfaction according to the engagement period with the bank only. The findings suggest better managing the loyalty programs and developing one credit card for all banks in Jordan.

• Environmental Engineering Research
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• v.24 no.2
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• pp.339-346
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• 2019

In this research, applicability of electrochemical technology in removing nitrogenous compounds from solid waste landfill leachate was examined. Novel cathode material was developed at laboratory by introducing a Cu layer on Al substrate (Cu/Al). Al and mild steel (MS) anodes were investigated for the efficiency in removing nitrogenous compounds from actual leachate samples collected from two open dump sites. Al anode showed better performances due to the effect of better electrocoagulation at Al surface compared to that at MS anode surface. Efficiency studies were carried out at a current density of $20mA/cm^2$ and at reaction duration of 6 h. Efficiency of removing nitrate-N using Al anode and developed Cu/Al cathode was around 90%. However, for raw leachate, total nitrogen (TN) removal efficiency was only around 30%. This is due to low ammonium-N removal as a result of low oxidation ability of Al. In addition to the removal of nitrogenous compounds, reactor showed about 30% removal of total organic carbon. Subsequently, raw leachate was diluted four times, to simulate pre-treated leachate. The diluted leachate was treated and around 88% removal of TN was achieved. Therefore, it can be said that the reactor would be good as a secondary or tertiary treatment step in a leachate treatment plant.

• Atmosphere
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• v.28 no.4
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• pp.491-507
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• 2018

This study collected and analyzed records related to the Asian dust phenomenon in Korean history books. I collected a wide range of records from diverse sources and identified data for analysis. 290 records were selected through this process. These records provide a variety of information including the occurrence time and duration of the phenomenon, other natural phenomenon occurring at the same date, descriptions of the phenomenon, and so on. Reports on, Asian dust in the historical records was not continuous or uniform. However, their appearance in certain months of the year is similar to that observed in modern times. In addition, I collected 90 records showing it that can be largely divided into two viewpoints which they were a natural calamity or an unusual phenomenon. Generally, natural phenomenons in historical books are mostly recorded in viewpoint of unusual phenomenon. Nevertheless, research result verified the record as actual observational data. Consequentially, it also indicates that this data is important for research from a meteorological point of view. I think that the data collected through this study can be helpful to modern meteorological studies related to the Asian dust phenomenon.

• Journal of Ocean Engineering and Technology
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• v.35 no.3
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• pp.203-215
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• 2021

Current industrial practices and approaches are simplified and do not describe the actual behavior of plated elements of offshore topside structures for safety design due to fires. Therefore, it is better to make up for the defective methods with integrated fire safety design methods based on fire resistance characteristics such as residual strength capacity. This study numerically investigates the residual strength of steel stiffened panels exposed to hydrocarbon jet fire. A series of nonlinear finite element analyses (FEAs) were carried out with varying probabilistic selected exposures in terms of the jet fire location, side, area, and duration. These were used to assess the effects of exposed fire on the residual strength of a steel stiffened panel on a ship-shaped offshore structure. A probabilistic approach with a feasible fire location was used to determine credible fire scenarios in association with thermal structural responses. Heat transfer analysis was performed to obtain the steel temperature, and then the residual strength was obtained for the credible fire scenarios under compressive axial loading using nonlinear FEA code. The results were used to derive closed-form expressions to predict the residual strength of steel stiffened panels with various exposure to jet fire characteristics. The results could be used to assess the sustainability of structures at risk of exposure to fire accidents in offshore installations.

• Journal of Engineering Education Research
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• v.24 no.2
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• pp.3-11
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• 2021

In the COVID-19 era, it was implemented to be used as a basic material for setting the direction of learning support and student guidance for university institutions and professors who are experiencing confusion. The purpose of this study is to compare the actual status of daily-routines of COVID-19 period, general semester period, and vacation period, and to examine whether there is a difference between the period of general semester and COVID-19 period, and whether there is a difference in daily use of COVID-19 period depending on grade. For this reason, a questionnaire survey was conducted from April 23 to 29, 2020, targeting students of University A, which is a small-scale technical centered university in the region, and 754 students answered. As a result of the study, first of all, when we looked at the trends in the use of daily-routines by period of general semester, vacation period, and COVID-19 period, the trends of the general semester period and COVID-19 period were similar in the areas of learning and self-development. Second, there were statistically significant differences in sleep, relaxation, learning and other areas between the period of the general semester and the duration of COVID-19. Third, there were statistically significant differences over grade in relaxation, learning, development, and other areas.

• Geomechanics and Engineering
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• v.28 no.1
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• pp.65-75
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• 2022

Time and cost of construction are key factors in decision-making during a tunnel project's planning and design phase. Estimations of time and cost of tunnel construction projects are subject to significant uncertainties caused by uncertain geotechnical and geological conditions. The Gaussian Process Regression (GPR) technique for predicting ground condition and construction time and cost of mountain tunnel projects is used in this work. The GPR model is trained with data from past mountain tunnel projects. The model is applied to a case study in which the predicted time and cost of tunnel construction using the GPR model are compared with the actual construction time and cost for model validation and reducing the uncertainty for the future projects. In addition, the results obtained from the GPR have been compared with to other models of artificial neural network (ANN) and support vector regression (SVR) that the GPR model provides more accurate results.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.639-640
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• 2015

Traditional construction planning based on historical data and heuristic adjustment can no longer incorporate all the operational details and guarantee the expected performance. The variation between the expected and the actual production leads to cost overruns or delay. Although predicting reliable productivity on construction site is getting more important, the difficulty of this increases. In this regard, this paper suggested to develop BIM-integrated simulation framework. This framework could predict productivity dynamics by considering factors affecting on construction productivity at operational phase. We developed the following processes; 1) enabling a BIM model to produce input data for simulation; 2) developing the construction operation simulation; 3) running simulation using BIM data and obtaining productivity results. The BIM-integrated simulation framework was tested with structural steel erection model because steel erection work is one of the most critical process influencing on the whole construction budget and duration. We could improve to predict more dynamic productivity from this framework, and this reliable productivity helps construction managers to optimize resource allocation, increase schedule reliability, save storage cost, and reduce material loss.