• Economic and Environmental Geology
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• v.55 no.5
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• pp.531-540
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• 2022

Various iron minerals that precipitate in acid mine drainage have a great influence on the concentration change and mobility of trace elements in the drainage during phase transition to other minerals as well as the precipitation process. This study investigated the change of mineral properties and the behaviors of trace elements influenced by pH and time for the precipitates collected from the acid mine drainage treatment system of the Dalsung mine, where schwertmannite is mainly precipitated. However, the main mineral precipitated in the drainage was goethite, suggesting schwetmannite has already undergone a phase transition to goethite to some extent, and it was observed that at higher pH, the peak width at half maximum of XRD peak was narrower. This can be interpreted as the transformation of small amount of amorphous schwetmannite to goethite or an increase in the crystallinity of goethite, and it showed that the higher the pH, the greater this change was. The concentration of Fe was also greatly affected by the pH values, and as the pH increased, the concentration of Fe in the drainage decreased. With increasing time, the Fe concentration increased and then decreased, which can be interpreted to indicate the dissolution of schwertmannite and precipitation of goethite. This mineral change probably resulted in the rapid increase of the concentration of S at initial stage, but its concentration was stabilized later. The concentration of S is also related to the stability of schwetmannite, showing a high concentration at a low pH at which schwertmannite is stable and a low concentration at a high pH at which goethite is stable. The trace elements present as cations in the drainage also showed a close relationship with the pH, generally the lower the pH, the higher the concentration, due to the solubility changes by the pH, and the precipitation and the changes in mineral surface charge at high pH. On the other hand, in the case of As, existing as an anion, although it showed a high concentration at low pH, its concentration increased with time at all pH values, which is probably related to the concentration of Fe which can be coprecipitated in the drainage, and the increase of As concentration with time is also considered to be related to the decrease in schwertmannite rather than the mineral surface charge.

• Journal of Environmental Health Sciences
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• v.25 no.3
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• pp.94-102
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• 1999

To estimate the effects of environmental noise on inhabitants' life in an apartment area at Taejon, noise levels and traffic volume of major roads were measured. 203 housewives were surveyed by questionaires including general factors, noise related factors and three items of life effects: subjective evaluations on the general environment, annoyance, and life disturbance due to environmental noise. At the boundary adjacent to the road with more traffic volume, noise level was higher; according to the time, the amount of noise level was in the morning, in the evening, at noon, and at night in order. Most of boundary noise levels were higher than those of recommended standard environmental noise levels in a residential area. The boundary noise level showed a very significant linear relationship with traffic volume of near roads. Noise level difference in the apartments adjacent to three roads was ranged 2.4~6.7dB between in windows open and close state. The apartments adjacent to 9 lane or 6 lane-road, which were protected by noise prevention wall and 20m or more distance from the roads, showed higher noise level at middle floors and high floors than those of low floors; but the buildings adjacent to 4 lane-road, with no protection, showed higher noise level at low and middle floors than those of high floors. Among 203 housewives, 120(59.1%) participated in this study, and 86(73.2%) of them answered that the most serious environmental noise was traffic noise from near roads. Comparing traffic noise levels with those of before-migration, 67.0% participants found the environmental noise became louder. Fifty eight(49.5%) of the participants wanted noise protection wall and 15(25.9%) of them were willing to charge the fee. Less perception on the present noise comparing to those before-migration, less traffic volume, and lower noise levels in the apartments were related to higher scores of self-evaluation on the environment. Higher susceptibility on the present noise, areas with more traffic volume, higher boundary noise levels, and higher noise levels showed higher scores of annoyance on environmental noise and life disturbance. Considering above all things, it was suggested that traffic noise in this area was the major problem of environmental noise, and its' effect was so serious that inhabitants needed some preventive measures for better life quality.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.461-467
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• 2020

Industrial consultation is a kind of personal service for companies. The Industry-Academic Cooperation Foundation sets up a consultation contract in which a professor performs the consultation as the person in charge. Recently, there is an issue regarding taxation of the consulting fee paid to the professor; in short, there is no standardized practice for the imposition of income tax. In this study, we examine the characteristics of industrial consultation and present an acceptable taxation rule based on related laws. First, it is not appropriate to regard consulting fees as wage income, considering that there is no employment relationship between the Industry-Academic Cooperation Foundation and the professor. Considering that the base consulting fee amount is the same as the invention compensation, according to accounting practices, and that an employee invention is apt to be derived in the consultation, it is reasonable that the consulting fee should be regarded as wage income similar to employee invention compensation. As treating the consulting fee as wage income could end up reducing industrial consultations, the government should amend the income tax law to include industrial consultation as a type of other income.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.71-78
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• 2020

In the case of power generation using renewable energy, power production may not be smooth due to the influence of the weather. The energy storage system (ESS) is used to increase the efficiency of solar and wind power generation. ESS has been continuously fired due to a lack of battery protection systems, operation management, and control system, or careless installation, leading to very big casualties and economic losses. ESS stability and battery protection system operation management technology is indispensable. In this paper, we present a battery level calculation algorithm and a failure prediction algorithm for ESS optimization and stable operation. The proposed algorithm calculates the correct battery level by accumulating the current amount in real-time when the battery is charged and discharged, and calculates the battery failure by using the voltage imbalance between battery cells. The proposed algorithms can predict the exact battery level and failure required to operate the ESS optimally. Therefore, accurate status information on ESS battery can be measured and reliably monitored to prevent large accidents.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.478-485
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• 2011

Merocyanine derivatives transformed from spiropyran-containing compounds by irradiating the light of ultraviolet (UV) include zwitterion of phenolate anion and amine cation. Complexation of this phenolate anion on merocyaninemodified surface and Ni ion among metal ions led to a change of surface charge and it was measured with kelvin prove force microscopy (KFM). We found that the resultant surface potential decreased linearly as UV-exposed time increased, and finally were saturated. Also it was analyzed through XPS the immobilized amount of Ni ions was increased according to increase of UV-exposed time. It is considered that these properties could be applied for detection and a quantitative control of different metal ions. Further research is to aim construct specific scaffold/matrix which enable high selective, high sensitive and, especially, a quantitative immobilization of metal ions-binding biomaterials such as proteins and cells.

• Journal of Digital Convergence
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• v.11 no.5
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• pp.347-354
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• 2013

In contrast to the increase in demand for high quality healthcare, there is limited medical human resources such as doctors and nurses so an excessive amount of workload is being forced to them. Therefore, a patient monitoring system using USN(Ubiquitous Sensor Network) is becoming a solution. This paper proposes a patient monitoring system applying USN in maternity hospital to reduce the workload of nurses. According to the efficiency evaluation test based on the model of two university hospitals(S, K University Hospital) and their doctor's diagnosis, the results showed that under the circumstances that one nurse is in charge of 12 patients(6 normal delivery patients and 6 cesarean delivery patients), a total of 1,260 minutes of workload was saved during hospitalization period(5 days). Also, we compared the workload of nurses with or without our proposed system, and the figures showed that in case of normal delivery patients, the workload of nurses decreased by 50 minutes per patient, whereas in case of cesarean delivery patients, the workload of nurses decreased by 130 minutes per patient.

• The Journal of Society for e-Business Studies
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• v.15 no.2
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• pp.37-53
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• 2010

As mobile communications service is growing every single year in Korea, it has pulled the interest of many researchers as wells as the executives. This research is aimed to find out factors of the mobile market that affect the utilization of mobile communication. We adopted a survey method with a pinpointed focus on how users' profile and individual experience relates with the utilization of mobile communication. For this objective, first, we primarily analyzed the mobile users' characteristics and service usage patterns. Then, we developed a conceptual model and hypotheses that are empirically examined using a covariance structure analysis, which will contribute to investigating critical success factors in mobile business. Some suggestions constitute the remaining part of this research. First, user characteristic is an important factor that affects the amount expended for mobile service. Second, user experience is another critical aspect that is highly linked with mobile payment. In alignment with our research, we propose user characteristics such as age and income, and user experience about mobile internet usage and mobile contents usage are of great significance in devising both near- and long-term mobile business strategy.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.3
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• pp.83-93
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• 2013

This study has been performed to analyze and consider the problems after 30 years in terms of landscape design competition process in Korea, so that it can provide the basic data, which can improve the future landscape design competition. We have used Delphi Investigation to carry out a survey that targets professionals and identifies problems. The results are summarized as follows. Firstly, the results of the analysis of Landscape Design Competition for institution theory and case studies showed that there is an issue from four perspectives which are 'method of design competition', 'guidelines for design competition', 'winner selection process', and 'design changes after winning' Secondly, the process by professional Delphi performed expert analysis, and agree with expert opinion. As a result, we derived the problems of a landscape design competition system with the 12 items. Third, in the 'design competition style', two items, the 'design competition style' and 'problem of design public offering period' had become a problem. Fourth, the 'Guidelines for design competition', 'non-hierarchical excess of the amount of instructions', 'directive determined the guidelines', and the 'provision of confusion' three items had also become a problem. Fifth, 'sex expert committee review selection process winning work', 'Problems of participation', 'examination scoring system experts lack', and 'non-landscaping' had become a problem. Sixth, 'The design of the original order' as much as possible 'design changes after the winning work' Four 'order to Comments to reduce the creativity of the design of the climate', 'original extension', 'contractor feedback of excess without the promise of frequent personnel changes', design period of the person in charge is reflected in excess item has become a problem. I considered that a continuous research on the improvement of the problems of the landscape design competition system based on the results must be performed.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.1
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• pp.132-137
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• 2020

Lithium secondary batteries have become an important power source for portable electronic devices such as cellular phones, laptop computers. Presently, commercialized lithium-ion batteries use a LiCoO₂ cathode. However, due to the high cost and environmental problems resulting from cobalt, an intensive search for new electrode materials is being actively conducted. Recently, solid solution LiMn_1-xNi_xO₂ have become attractive because of high capacity and enhanced safety at high voltages over 4.5 V. The Li_1.6Ni_0.35Mn_0.65O₂ compounds were conventionally prepared by a sol-gel method, which can produce the layered Li-Ni-Mn-O compounds with a high homogeneity. And by adding a graphene 2wt% the first charge-discharge voltage profiles was increased over Li_1.6Ni_0.35Mn_0.65O₂ compound. Also, the variation s of the discharge capacities with cycling showed a higher capacity retention rater. In this study, material lifecycle evaluation was performed to analyze the environmental impact characteristics of Li_1.6Ni_0.35Mn_0.65O₂ & graphene 2wt% half-cell manufacturing process. The software of material life cycle assessment was Gabi. Through this, environmental impact assessment was performed for each process. The environmental loads induced by Li_1.6Ni_0.35Mn_0.65O₂ & graphene 2wt% synthesis process were quantified and analyzed, and the results showed that the amount of power had the greatest impact on the environment.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.626-632
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• 2015

The International Maritime Organization (IMO) has adopted several regulations for the prevention of air pollution from ships. In addition, there is a requirement for shipping liners to reduce greenhouse gas emissions. Accordingly, we need to take measurements to ensure that the steps taken are both efficient and environmentally friendly. It has been determined that the application of the Miller cycle in diesel engines has the effect of both reducing the amount of NOx and improving thermal efficiency. However, this method requires a considerably larger charge air pressure. Therefore, we consider a two-stage turbo-charging system, which not only results in a high charging pressure, but also improves the part load performance with an exhaust-gas bypass system or the application of the Miller cycle. Because of complications associated with the two-stage turbo-charging system, it is complex and difficult to realize a design that optimizes matching between diesel engine and turbo-chargers. Accordingly, it is necessary to perform a quantitative analysis to determine the effects and optimal conditions of these different systems in the early stage of system design. In this paper, we develop a simulation program to model these systems, and we verify that the results of this program are reliable. Further, we discuss methods that can be employed to improve its efficiency.