• Journal of Navigation and Port Research
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• v.42 no.1
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• pp.9-16
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• 2018

The development of limited petroleum resources for use with mankind inevitably explores and seeks to develop oil fields in the deep sea area, under the rise of the oil prices market situation. The use of Oceanic Thermal Energy Conversion (OTEC) technology, which operates the power generation facility using the temperature differences between the deep water and the surface water, is progressing actively as a trend to follow. In this study, the application of the Discharged Thermal Energy Conversion (DTEC) was designed and analyzed under the condition that the supply condition of seawater used in the FPSO installed in the deep sea area is changed up to 400m depth. In this case, it was confirmed that the design of the system that can generate more electric power according to the depth of water is confirmed, by thus applying the DTEC system by taking the cooling water at a deeper water depth than the existing design water depth. The FPSO considers the similarity of the OTEC power generation facilities, and will apply the DTEC system to FPSO in the deep sea area to accumulate technology and the conversion to further utilize the OTEC power generation facilities after the end of life cycle of oil production, which could be a solution to two important issues, namely, resource development and sustainable development.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.44-45
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• 2010

We are currently conducting studies on culturing and biocompatibility assessment of various cells such as neural stem cells and induced pluripotent stem cells(IPS cells) on carbon nanotube (CNT), on nerve regeneration electrodes, and on silicon wafers with a focus on developing nerve integrated CNT based bio devices for interfacing with living organisms, in order to develop brain-machine interfaces (BMI). In addition, we are carried out the chemical modification of carbon nanotube (mainly SWCNTs)-based bio-nanosensors by the plasma ion irradiation (plasma activation) method, and provide a characteristic evaluation of a bio-nanosensor using bovine serum albumin (BSA)/anti-BSA binding and oligonucleotide hybridization. On the other hand, the researches in the case of "novel plasma" have been widely conducted in the fields of chemistry, solid physics, and nanomaterial science. From the above-mentioned background, we are conducting basic experiments on direct irradiation of body tissues and cells using a micro-spot atmospheric pressure plasma source. The device is a coaxial structure having a tungsten wire installed inside a glass capillary, and a grounded ring electrode wrapped on the outside. The conditions of plasma generation are as follows: applied voltage: 5-9 kV, frequency: 1-3 kHz, helium (He) gas flow: 1-1.5 L/min, and plasma irradiation time: 1-300 sec. The experiment was conducted by preparing a culture medium containing mouse fibroblasts (NIH3T3) on a culture dish. A culture dish irradiated with plasma was introduced into a $CO_2$-incubator. The small animals used in the experiment involving plasma irradiation into living tissue were rat, rabbit, and pick and are deeply anesthetized with the gas anesthesia. According to the dependency of cell numbers against the plasma irradiation time, when only He gas was flowed, the growth of cells was inhibited as the floatation of cells caused by gas agitation inside the culture was promoted. On the other hand, there was no floatation of cells and healthy growth was observed when plasma was irradiated. Furthermore, in an experiment testing the effects of plasma irradiation on rats that were artificially given burn wounds, no evidence of electric shock injuries was found in the irradiated areas. In fact, the observed evidence of healing and improvements of the burn wounds suggested the presence of healing effects due to the growth factors in the tissues. Therefore, it appears that the interaction due to ion/radicalcollisions causes a substantial effect on the proliferation of growth factors such as epidermal growth factor (EGF), nerve growth factor (NGF), and transforming growth factor (TGF) that are present in the cells.

• Journal of the HCI Society of Korea
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• v.14 no.2
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• pp.49-60
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• 2019

With the appearance of self-driving cars and electric cars, the automobile industry is rapidly changing. In the midst of these changes, HMI studies are becoming more important as to how the driver obtains safety and convenience with controlling the vehicle. This study sought to understand how automobile manufacturers understand the driving situation, and how they define and limit driver interaction. For this, prior studies about HMI were reviewed and 15 participants performed an on-road study to drive vehicles from five manufacturers with using their interfaces. The results of the study confirmed that buttons and switches that are easily controlled by the user while driving were different from manufacturer to manufacturer. And there are some buttons that are more intensively controlled and others that are difficult to control while driving. It was able to derive 'selection and concentration' from Audi's vehicle, 'optimization of the driving ' from BMW's, 'simple and minimize' from Benz's vehicle, 'remove the manual distraction' from the vehicle of Lexus, and 'visual stability' from KIA's vehicle as the distinctive keywords for the HMI. This shows that each manufacturer has a different definition and interpretation of the driver's driving control area. This study has a distinct value in that it has identified the characteristics of vehicle-specific HMI in actual driving conditions, which is not apparent in appearance. It is expected that this research approach can be useful to see differences in interaction through actual driving despite changes in driving environment such as vehicle platooning and self-driving technology.

• Journal of the Korean GEO-environmental Society
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• v.12 no.1
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• pp.51-60
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• 2011

Electrical resistivity is applied for understanding details about layers and obtaining basic properties of soils to various measurement devices. The objective of this study is development of TRP(Temperature-compensated Resistivity Probe), analysis about effects of temperature changes during cone penetration test, and observation of characteristics of cone penetration. In order to observation of temperature changes according to a diameter difference of resistivity cone probe, the cone which has wedge type cone tip is made to two types, 2mm and 5mm. Temperature sensor is attached at 15mm below from cone tip because of an electrical interference with elecrical resistance probe. Delectrical connector is used to prevent electric disturbance between motor type penetrating machine and electrical resistivity cone probe. Application tests are carried out in acrylic cell whose diameter is 30cm with uniform Jumunjin sand according to densification caused by blows. The test results indicate that the temperature is increased uniformly during penetration and a tendency, characteristics of cone penetration, is discovered during altering state of soils. This study suggests that the temperature effects and characteristics of penetration should be considered in penetrating tests in order to conduct an accurate ground investigation using TRP(Temperature-compensated Resistivity Probe).

• Journal of Environmental Health Sciences
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• v.47 no.3
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• pp.259-266
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• 2021

Objectives: This study was conducted to identify the emissions characteristics of total particulate matter (TPM), fine dust (PM₁₀, PM_2.5), and gaseous pollutants (SOx, NOx) in iron and steel manufacturing facilities in order to investigate emissions factors suitable for domestic conditions. Methods: Total particulate matter (TPM), fine dust (PM₁₀, PM_2.5), and gas phase materials were investigated at the outlet of electric arc furnace facilities using a cyclone sampling machine and a gas analyzer. Results: The concentrations of TPM ranged from 1.64 to 3.14 mg/Sm³ and the average was 2.47 mg/Sm³. Particulate matter 10 (PM₁₀) averaged 1.49 mg/Sm³ with a range of 0.92 to 1.99 mg/Sm³, and the resulting ratio of PM₁₀ to TPM was around 60 percent. PM_2.5/PM₁₀ ranged from 33.7 to 47.9% and averaged 41.6%. Sulfur oxides (SOx) were not detected, and nitrogen oxides (NOx) averaged 6.8 ppm in the range of 5.50 to 8.67 ppm. TPM emission coefficients per product output were in the range of 0.60 to 1.26 g/kg, 0.13 to 0.79 g/kg for PM₁₀ and 0.12 to 0.36 g/kg for PM_2.5, and showed many differences from the emissions coefficients previously announced. An emissions coefficient for NOx is not currently included in the domestic notices, but the results were calculated to be 0.42 g/kg per product output. Conclusions: Investigation and research on emissions coefficients that can reflect the characteristics of various facilities in Korea should be conducted continuously, and the determination and application of unique emissions coefficients that are more suitable for domestic conditions are needed.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.8
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• pp.339-346
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• 2022

Recently, the resource depletion and climate change problem caused by the massive usage of fossil fuels for electric power generation has become a critical issue worldwide. According to this issue, interest in renewable energy resources that can replace fossil fuels is increasing. Especially, photovoltaic power has gaining much attention because there is no risk of resource exhaustion compared to other energy resources and there are low restrictions on installation of photovoltaic system. In order to use the power generated by the photovoltaic system efficiently, a more accurate photovoltaic power forecasting model is required. So far, even though many machine learning and deep learning-based photovoltaic power forecasting models have been proposed, they showed limited success in terms of interpretability. Deep learning-based forecasting models have the disadvantage of being difficult to explain how the forecasting results are derived. To solve this problem, many studies are being conducted on explainable artificial intelligence technique. The reliability of the model can be secured if it is possible to interpret how the model derives the results. Also, the model can be improved to increase the forecasting accuracy based on the analysis results. Therefore, in this paper, we propose an explainable photovoltaic power forecasting scheme based on BiLSTM (Bidirectional Long Short-Term Memory) and SHAP (SHapley Additive exPlanations).

• Journal of Environmental Health Sciences
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• v.40 no.6
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• pp.454-468
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• 2014

Objectives: This study was conducted to investigate the actual condition of the farm work environment and personal protective equipment as part of the effort to improve livestock work for the safety and health of poultry farmers and provide basic data for establishing plans to improve and develop personal protective equipment. Methods: For this purpose, a questionnaire survey on general information about stables, the poultry work environment, accidents, the wearing of work clothes and personal protective equipment, and the level of awareness related to personal protective equipment was conducted among 148 poultry farmers. Results: As a result, it was found that poultry workplace environment was exposed to such risks as fine dusts; organic dusts; poisonous gases; odorous substances; chicken excrement; contact with chickens, bacteria or viruses; and accidents related to machine operation. Thirteen percent of respondents suffered severe respiratory diseases, and the most frequently injured sites due to accidents were the hands (25.7%), knees (23.8%), arms (17.3%), and head (10.9%). The most frequent type of accident was collisions between the body and obstacles or machinery during movement (36.4%), followed by erroneous machine operation such as feeders and electric shocks (8.5%). Regarding the wearing of work clothes and personal protective equipment, 51.7% of the respondents wore worn-out clothing or everyday clothes, whereas only 32.0% wore work clothes. The percentage of farmers who wore proper protective equipment for the work environment during poultry work was 48.4%. The most frequently used type of protective equipment was boots (38.9%), followed by mask (36.7%), gloves (36.3%), appropriate work clothes (22.6%), quarantine clothes (17.6%), helmets (13.4%), and goggles (12.6%). The rate of wearing goggles was low because they were considered inconvenient and lowered work efficiency. Furthermore, they purchased everyday products available on the market for their personal protective equipment which were not appropriate for maintaining safety in an actual harmful environment and its consequent risks. As a result of the survey of the awareness level related to personal protective equipment, their levels of awareness of accidents and attitude proved to be average or higher, but the practice of wearing protective equipment and the level of knowledge and management of personal protective equipment were lower. Conclusion: This survey found that the wearing status of personal protective equipment among poultry farmers was insufficient even though they were exposed to risks. Most respondents were aware of the necessity of wearing personal protective equipment and of the potential for accidents, but they did not wear proper protective equipment. Their wearing rate was low due to a lack of knowledge about protective equipment, as well as the inconvenience of wearing it. Therefore there is a need to improve and develop specialized personal protective equipment for respiration, hands, and eyes, as well as work clothes that can protect farmers from major harmful matter that is generated in the poultry workplace. Based on the results of this investigation, we will conduct further studies on the required performance and design directions of personal protective equipment while collecting more objective data through field-oriented assessments.

• Progress in Medical Physics
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• v.20 no.4
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• pp.235-243
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• 2009

The purpose of this experiment is to know the relation of the detection and characterization of liver's diseases as comparison of finding at MR imaging using a Ferucarbotran (SPIO) and Gd-EOB-DTPA (Primovist) agents in diffuse liver disease. A total of 50 patients (25 men and 25 women, mean age: 50 years) with liver diseases were investigated at 3.0T machine (GE, General Electric Medical System, Excite HD) "with 8 Ch body coil for comparison of diseases and contrast's uptake relation, which used the LAVA, MGRE." All images were performed on the same location with before and after Ferucarbotran and Gd-EOB-DTPA administrations (p<0.05). Contrast to noise ratio of Ferucarbotran and Gd-EOB-DTPA in the HCC were $3.08{\pm}0.12$ and $7.00{\pm}0.27$ with MGRE and LAVA pulse sequence, $3.62{\pm}0.13$ and $2.60{\pm}0.23$ in the hyper-plastic nodule, $1.70{\pm}0.09$ and $2.60{\pm}0.23$ in the meta, $2.12{\pm}0.28$ and $5.86{\pm}0.28$ in the FNH, $4.45{\pm}0.28$ and $1.73{\pm}0.02$ in the abscess and ANOVA test was used to evaluate the diagnostic performance of each disease (p<0.05). In conclusions, two techniques were well demonstrated with the relation of the detection and characterization of liver's diseases.

• Journal of Technologic Dentistry
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• v.20 no.1
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• pp.37-49
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• 1998

The specimens used were Ag-25 Pd-15 Cu ternary alloy and Au addition alloy. These alloys were melted and casted by induction electric furnace and centrifugal casting machine in Ar atmosphere. These specimens were solution treated for 2hr at $800^{\circ}C$ and were then quenched into iced water, and aged at $350{\sim}550^{\circ}C$ Age- hardening characteristics of the small Au-containing Ag-Pd-Cu dental alloys were investigated by means of hardness testing. X-ray diffraction and electron microscope observations, electrical resistance, ergy dispersed spectra and electron probe microanalysis. Principal results are as follows : Hardening occured in two stages, i.e., stage I in low temperature and stage II in high temperature regions, during continuous aging. The case of hardening in stage I was due to the formation of the $L1_0$ type face-centered tetragonal PdCu-ordered phase in the grain interior and hardening in stage I was affected by the Cu concentration. In stage II, decomposition of the ${\alpha}$ solid solution to a PdCu ordered phase($L1_0$ type) and an Ag-rich ${\alpha}2$ phase occurred and a discontinuous precipitation occurred at the grain boundary. From the electron microscope study, it was conclued that the cause of age-hardening in this alloy is the precipitation of the PdCu ordered phase, which has AuCu I type face-centered tetragonal structure. Precipetation procedure was ${\alpha}{\to}{\alpha}+{\alpha}_2+PdCu {\to}{\alpha}_1+{\alpha}_2+PdCu$ at Pd/Cu = 1.7 Ag-Pd-Cu alloy is more effective dental alloy as ageing treatment and is suitable to isothermal ageing at $450^{\circ}C$.

• Journal of Technologic Dentistry
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• v.21 no.1
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• pp.27-41
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• 1999

The Ag-Pd-Cu alloys containing a small amount of Au is commonly used for dental purposes, because this alloy cheaper than Au-base alloys for clinical use. However, the most important characteristic of this alloy is age-hardenability, which is not exhibited by other Ag-base dental alloys. The specimens used were Ag-30Pd-10Cu ternary alloy and Au addition alloy. These alloys were melted and casted by induction electric furnace and centrifugal casting machine in Ar atmosphere. These specimens were solution treated for 2hr at $800^{\circ}C$ and were then quenched into iced water, and aged at 350-$550^{\circ}C$ Age-hardening characteristic of the small Au-containing Ag-Pd-Cu dental alloys were investigated by means of hardness testing, X-ray diffraction and electron microscope observations, electrical resistance, differential scanning calorimetric, energy dispersed spectra and electron probe microanalysis. Principal results are as follows ; Maximum hardening occured in two co-phases of ${\alpha}_2$ + PdCu In stage II, decomposition of the $\alpha$ solid solution to a PdCu ordered phase($L1_o$ type) and an Ag-rich ${\alpha}_2$ phase occurred and a discontinuous precipitation occurred at the grain boundary. From the electron microscope study, it was concluded that the cause of age-hardening in this alloy is the precipitation of the PdCu redered phase, which has AuCu I type face-centered tetragonal structure. Precipitation procedure was ${\alpha}{\to}{\alpha}_1+PdCu{\to}{\alpha}_2+PdCu$ at Pd/Cu = 3 Pd element of Ag-Pd-Cu alloy is more effective dental alloy on anti-corrosion and is suitable to isothermal ageing at $450^{\circ}C$.