• Korean Security Journal
• /
• no.28
• /
• pp.7-31
• /
• 2011

The purpose of this study was to examine the relationship of the psychological empowerment of security guards to their service orientation and organizational performance. The subjects in this study were 300 security guards who were selected by purposive sampling from the population that consisted of the workers in private security agencies located in the cities of Chungan and Ahsan in 2011. After a survey was conducted, the answer sheets from 271 respondents were analyzed. The statistical package SPSS WIN 18.0 was employed to make a factor analysis, reliability analysis, multiple regression analysis and path analysis. The findings of the study were as follows: First, psychological empowerment affected service orientation. Better meaning and better self-determination led to better service human resources management, better service leadership and better service encounter management. Second, psychological empowerment exerted an influence on organizational performance. Stronger impact and better meaning led to stronger organizational commitment, higher job satisfaction and better performance. Third, service orientation had an impact on organizational performance. Better service human resources management, better service leadership and better service encounter management were followed by stronger organizational commitment, better job satisfaction and higher performance. Fourth, psychological empowerment exercised a firsthand and secondhand influence on service orientation and organizational performance. Given the findings of the study, managers of security agencies should keep in mind the unique working environments of employees, and they should empower employees to show what they can do in consideration of their changing working environments and let them assume the responsibility for their own job performance. That will encourage them to provide better service for customers, which will serve, in turn, to bolster the organizational performance.

• Journal of Soil and Groundwater Environment
• /
• v.19 no.2
• /
• pp.7-15
• /
• 2014

This study was conducted to understand the chemical characteristics of groundwater in carbonate areas of Korea. In this study, data on pH, electric conductivity (EC), $Ca^{2+}$, $Mg^{2+}$, $Na^+$, $K^+$, $Cl^-$, $SO_4{^{2-}}$, and $HCO_3{^-}$ were collected from 97 wells which were installed in various carbonate rock regions of Korea. The pH values ranged from 5.7 to 9.9, and the average value was 7.3. The concentration range showed differences between the maximum value of $HCO_3{^-}$ and the medium to minimum values of $Ca^{2+}$, $Mg^{2+}$, $Na^+$, $Cl^-$, $SO_4{^{2-}}$, and $K^+$ in the study area. The average value of EC was $374{\mu}S/cm$, higher than in granite and gneiss areas, where the value is $176{\mu}S/cm$. Most of the groundwater was type $Ca-HCO_3$, and some was type $Mg-HCO_3$. The relationship between $Ca^{2+}$, $Cl^-$, and $HCO_3{^-}$, respectively, and EC showed relatively significant positive correlations compared to the other dissolved components. However, the determination coefficients for $Mg^{2+}$, $Na^+$, $SO_4{^{2-}}$, and $K^+$ were very low less than 0.2. These results indicate that the source of $Ca^{2+}$ and $Mg^{2+}$ is relatively simple (carbonate dissolution) compared to other sources. The sources of $Na^+$, $K^+$, $Cl^-$, $SO_4{^{2-}}$, and $HCO_3{^-}$ might be not only water-rock interactions, but also irrigation return flow, because many groundwater wells had been developed for irrigation purposes. Subsequently, the influence of agriculture on groundwater chemistry was evaluated using a cumulative plot of $SO_4{^{2-}}$. The threshold value of $SO_4{^{2-}}$ calculated from the cumulative frequency curve was 29.2 mg/L. Therefore, 12.4% of all the groundwater wells were affected by agricultural activity.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.10
• /
• pp.403-411
• /
• 2016

Recently, the number of occurrences of inundation and the severity of flood damage has increased rapidly as the frequency of localized heavy rainfall and the ratio of impervious area increased in urban areas. Most local governments focus on employing structural measures (e.g., the construction of detention reservoirs/pump stations, rehabilitation of drainage and sewer pipes) to prevent urban inundation. On the other hand, the effectiveness of implementing such structural measures is being dimished because there are already many inundation prevention facilities. The limitation of structural measures can be overcoming by employing non-structure measures, such as flood alerts and the operation of drainage facilities. This study suggests the pump operation rule (i.e., suggesting pump stop level) for a new detention reservoir operating method, which triggers the operation of a pump based on the water level at the monitoring node in urban drainage system. In the new reservoir operation, a total of 48 rainfall events are generated by the Huff distribution for determining the proper pump stop level. First, the generated rainfall events are distributed as frequencies, quartiles, and durations. The averaged system resilience value was determined to range from 1.2 m to 1.5 m is based on the rainfall-runoff simulation with rainfall generated by the Huff distribution. In this range, 1.2 m was identified considering the safety factor of 1.25 by the Standard on sewer facilities in 2011.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.17 no.2
• /
• pp.47-57
• /
• 2019

Purpose: Osmolar gap (OG) has been used for decades to screen for toxic alcohol levels. However, its reliability may vary due to several reasons. We validated the estimated ethanol concentration formula for patients with suspected poisoning and who visited the emergency department. We examined discrepancies in the ethanol level and patient characteristics by applying this formula when it was used to screen for intoxication due to toxic levels of alcohol. Methods: We retrospectively reviewed 153 emergency department cases to determine the measured levels of toxic ethanol ingestion and we calculated alcohol ingestion using a formula based on serum osmolality. Those patients who were subjected to simultaneous measurements of osmolality, sodium, urea, glucose, and ethanol were included in this study. Patients with exposure to other toxic alcohols (methanol, ethylene glycol, or isopropanol) or poisons that affect osmolality were excluded. OG (the measured-calculated serum osmolality) was used to determine the calculated ethanol concentration. Results: Among the 153 included cases, 114 had normal OGs (OG≤14 mOsm/kg), and 39 cases had elevated OGs (OG>14). The mean difference between the measured and estimated (calculated ethanol using OG) ethanol concentration was -9.8 mg/dL. The 95% limits of agreement were -121.1 and 101.5 mg/dL, and the correlation coefficient R was 0.7037. For the four subgroups stratified by comorbidities and poisoning, the correlation coefficients R were 0.692, 0.588, 0.835, and 0.412, respectively, and the mean differences in measurement between the measured and calculated ethanol levels were -2.4 mg/dL, -48.8 mg/dL, 9.4 mg/dL, and -4.7 mg/dL, respectively. The equation plots had wide limits of agreement. Conclusion: We found that there were some discrepancies between OGs and the calculated ethanol concentrations. Addition of a correction factor for unmeasured osmoles to the equation of the calculated serum osmolality would help mitigate these discrepancies.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.6
• /
• pp.822-831
• /
• 2021

Although programs have been developed to evaluate the risk of dragging anchors, it is practically difficult for VTS(vessel traffic service) operators to calculate and evaluate these risks by obtaining input factors from anchored ships. Therefore, in this study, the gross tonnage (GT) that could be easily obtained from the ship by the VTS operators was set as an independent variable, and linear and nonlinear regression analyses were performed using the input factors as the dependent variables. From comparing the fit of the polynomial model (linear) and power series model (nonlinear), the power series model was evaluated to be more suitable for all input factors in the case of container ships and bulk carriers. However, in the case of tanker ships, the power supply model was suitable for the LBP(length between perpendiculars), width, and draft, and the polynomial model was evaluated to be more suitable for the front wind pressure area, weight of the anchor, equipment number, and height of the hawse pipe from the bottom of the ship. In addition, all other dependent variables, except for the front wind pressure area factor of the tanker ship, showed high degrees of fit with a coefficient of determination (R-squared value) of 0.7 or more. Therefore, among the input factors of the dragging anchor risk assessment program, all factors except the external force, seabed quality, water depth, and amount of anchor chain let out are automatically applied by the regression analysis model formula when only the GT of the ship is provided.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
• /
• v.55 no.6
• /
• pp.527-537
• /
• 2018

Column tests of a sulfate reducing bacteria (SRB) bioreactor were conducted to determine the design factors for sulfate-rich mine drainage. Various substrates were applied to the bioreactor, including cow manure and its mixture with a mushroom compost, with rice straw and limestone as subsidiary materials. This procedure provided a removal efficiency of up to 82% of the total sulfur with the mixture of cow manure (70%), mushroom compost (10%) and rice straw (20%), and higher efficiencies were observed after 2 days of retention time. In the downflow condition of the flow direction, oxygen supply and re-oxidation of the sulfates occurred, causing a decrease in sulfate removal efficiency. The addition of an inorganic sludge containing heavy metals, which was intended for production of metal-sulfides in the bioreactor, had a negative effect on the long-term operation owing to arsenic release and toxicity to the SRB. The results thus show that a bioreactor using a mixed substrate with cow manure and operating in the downflow direction could reduce sulfates and total dissolved sulfur content; this process confirms the applicability of the SRB bioreactor to sulfate-rich saline drainage.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.9
• /
• pp.341-350
• /
• 2019

This research study was conducted to investigate the effect of knowledge, attitude and nursing professionalism on the confidence of the performance of nursing students who had experience with clinical practice and also to provide basic data for the development of nursing students' curriculum. The subjects who participated in this study were 286 students in the 4th year of nursing at two colleges in the Daegu and Gyeongbuk regions. The research data was analyzed using the SPSS 22.0 program. Confidence in performance of patient safety was higher for the women than for men, and for the students of an older age and higher academic achievement. Confidence in performance of patient safety was positively related to knowledge (r=.25, p=.000), attitude (r=.39, p=.000), nursing professionalism (r=.33, p=.000) and all these had statistical significance. On the multiple regression analysis, the coefficient of determination ($R^2$) was .49 and the explanatory power of the model was 49.2% (F=24.04, p=.000). The most important factor affecting confidence in performance of patient safety was the experience of having undergone patient safety education. Based on these results, it is necessary to seek various educational methods to expand the concept of patient safety from the beginning of the undergraduate course work. Especially, we think that various education strategies such as simulation education methods or information videos are needed to develop scenarios related to patient safety.

• Journal of Mushroom
• /
• v.19 no.1
• /
• pp.71-75
• /
• 2021

We analyzed the relationship between the main chemical properties (pH, total nitrogen content, total carbon content, and CN ratio) of sterilized medium and mushroom yields in 1 kg bag culture of Pleurotus ostreatus. The mushroom yields appeared to be highly correlated with the pH, total nitrogen content, and CN ratio, and were the highest under a total nitrogen content of 2.0-2.2% and a the CN ratio of 20-22.5. However, of the three parameters, total nitrogen content showed the highest correlation with the mushroom yield. The coefficient of determination(r2) between the total nitrogen content and the sum of the yield was 0.931, while that of the pH and CN ratio was relatively low. The nitrogen content of the medium was the most important factor in determining the yield of oyster mushrooms.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.29 no.4
• /
• pp.55-65
• /
• 2021

This study investigated methane productions and a degradation rate of organic matters by German standard method, VDI4630 test. In this study, 11 waste biomasses from agricultural fields were selected for the investigation. The objective of this study was to estimate a distribution of organic matters by using the Double first-order kinetics model in order to calculate the rate of biodegradable organic matters which degrade rapidly in the initial stage and the persistently biodegradable organic matters which degrade slowly later. As a result, all the biomasses applied in this study showed rapid decomposition in the initial stage. Then the decomposition rate began to slow down for a certain period and the rate became 10 times slower than the initial decomposition rate. This trend of decomposition rate changes is typical conditions of biomass decompositions. The easily degradable factors (k₁) were raged between 0.097~0.152 day^-1 from vegetable crops and persistent degradable factor (k₂) were 0.002~0.024 day^-1. Among these results, greater organic matter decomposition rates from VDI4630 had greater k₁ values (0.152, 0.144day^-1) and smaller k₁ values (0.002, 0.005day^-1) from cucumbers and paprika. In a meanwhile, radishes and tangerine rinds which had low decomposition rates showed 0.097 and 0.094 day^-1 of k₁ values and decomposition rates seems to affect k₁ values.

• Smart Media Journal
• /
• v.11 no.5
• /
• pp.75-81
• /
• 2022

In order to respond to carbon neutrality and climate change in agriculture, agricultural machinery, which has been developed centered on internal combustion engines, needs to be converted to an electric-based technology that does not emit greenhouse gases. In this study, simulations for electric UTV suspension design were performed to reduce vibration and shock of electric UTV for agricultural use and to improve driving stability and control performance of the vehicle. The simulation was performed by dividing the tolerance load of the vehicle body and the loaded load state. The range of motion of the suspension spring of UTV is within 30% of the range of motion under condition B under tolerance, the displacement of the UTV suspension with full load is reduced from 264mm to 121mm, and the damping speed is 260mm/s to 300mm/s that it can be seen that the range of motion is within 60%. Suspension design of electric UTV for multi-purpose agricultural work is a very important factor for maintaining agricultural work ability in towing work such as tillage as well as driving and terrain adaptation. The results of this study can be usefully used to determine the spring parameters with the appropriate damping range so that the electric UTV can be used for various agricultural tasks.