• Journal of Korea Water Resources Association
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• v.31 no.6
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• pp.779-793
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• 1998

In this study, for the purpose of water supply planning, we propose a sophisticated multi-period mixed integer programming model that can coordinate the behavior of multi-reservoir operation, minimizing unnecessary spill. It can simulate the system with operating rules which are self- generated by the optimization engine in the algorithm. It is an optimization model in structure, but it indeed simulates the coordinating behavior of multi-reservoir operation. It minimizes the water shortfalls in demand requirements, maintaining flood reserve volume, minimizing unnecessary spill, maximizing hydropower generation release, keeping water storage levels high for efficient hydroelectric turbine operation. This optimization model is a large scale mixed integer programming problem that consists of 3.920 integer variables and 68.658 by 132.384 node-arc incidence matrix for 28 years of data. In order to handle the enormous amount of data generated by a big mathematical model, the utilization of DBMS (data base management system)seems to be inevitable. It has been tested with the Han River multi-reservoir system in Korea, which consists of 2 large multipurpose dams and 3 hydroelectric dams. We demonstrated successfully that there is a good chance of saving substantial amount of water should it be put to use in real time with a good inflow forecasting system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.157-162
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• 2018

The increase of risk in port due to the increase in ship size and sea level rises, the standard crown height will increase. In this study, cruise and container ships will need to raise their crown height due to the projected wind pressure areas becoming larger due to the ships' size increase. The mooring assessment was evaluated with the rise of the crown height. The cruise ship of GT 100,000 tons exceeded the permissible breaking force of the mooring line under the crown height conditions of wind speed of 30 kts when the wind direction was $45^{\circ}$ to the direction of the bow. Also, the elevation angle of the pier and mooring line was analyzed and exceeded the crown height, and it was determined that it is necessary to adjust the crown height. Container ships of DWT 100,000 tons were analyzed to exceed the limit of sway motion at the crown height and it was determined that they need to be adjusted to the minimum crown height standard.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.3
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• pp.227-231
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• 2010

Among various make-up products, foundations are widely used to express clear and flawless skin. Foundations can be classified by its formula to 3 types, liquid foundation, powder foundation, and oil dispersion foundation. Powder foundations are easy to carry and use, so it is commonly possessed. In the R&D point of view, the developing method of powder foundations can be classified again to 3 types. Dry-process, baked-process, and the wet slurry-process. The fact that the wet slurry-process goes through either the back injection method or the front injection method is previously known. The front injection process is used as the main method in this study. We observed the quality dependence on the kind of solvent and the powder coating system. In brief, when water was used as the main solvent, the hardness increased than when volatile silicones or hydrocarbons were used. And the sensory results were shown to prefer volatile solvents (silicones or hydrocarbons) over water. Similarly, when the amino acid-coating system was applied, the hardness was shown to increase, when silicone-coating system shown no specific change. By these results, tailor-made powder foundations targeting specific customer grades can be easily produced.

• Journal of Digital Convergence
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• v.15 no.1
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• pp.227-238
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• 2017

Cardiac arrest is a serious intensive emergency disease that causes death within less than several minutes by depriving the body and brain of blood supply. Survival rate of cardiac arrest patients outside of hospitals is especially low. This is because pedestrians usually do not perceive the patient as a sick person, also, even if they do so, they have no medical knowledge to properly react to such emergency. The purpose of this study is to propose a solution that uses widely spread smart phones to alert pedestrians of the cardiac arrest patient, prevents cardiac arrest, and provides first-aid measures. By applying the proposed solution, cardiac arrest can be prevented in advance, pedestrians can be alerted to keep the golden time(4 minutes), and first witness can quickly proceed with CPR, ultimately enhancing the survival rate of the cardiac arrest patient.

• The Journal of the Acoustical Society of Korea
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• v.39 no.5
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• pp.441-446
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• 2020

In this paper, we propose the α-Feature Map Scaling (α-FMS) method which extends the FMS method that was designed to enhance the discriminative power of feature maps of deep neural networks in Speaker Verification (SV) systems. The FMS derives a scale vector from a feature map and then adds or multiplies them to the features, or sequentially apply both operations. However, the FMS method not only uses an identical scale vector for both addition and multiplication, but also has a limitation that it can only add a value between zero and one in case of addition. In this study, to overcome these limitations, we propose α-FMS to add a trainable parameter α to the feature map element-wise, and then multiply a scale vector. We compare the performance of the two methods: the one where α is a scalar, and the other where it is a vector. Both α-FMS methods are applied after each residual block of the deep neural network. The proposed system using the α-FMS methods are trained using the RawNet2 and tested using the VoxCeleb1 evaluation set. The result demonstrates an equal error rate of 2.47 % and 2.31 % for the two α-FMS methods respectively.

• The Journal of Society for e-Business Studies
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• v.8 no.4
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• pp.129-149
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• 2003

Explosive growth of mobile devices over the past years has greatly increased commercial interests in mobile commerce, but mobile commerce has not yet seen enough increase on demand side as anticipated. Despite the slow start, mobile commerce has a lot of potential from users' perspective. In order to make this potential a reality, businesses must focus on the values from their customers' perspective, not technical competencies. This research employed Keeney's(1992) value focused thinking approach and explore values of mobile commerce from actual users' viewpoint. In depth interviews were conducted with seventy Practical users of mobile commerce. Through an extensive focus group sessions, 748 statements obtained from actual users were classified into 18 categories of means objectives and 12 categories of fundamental objectives of mobile commerce. The means-ends network diagram of values seen in mobile commerce by actual users were presented and compared to typical electronic commerce diagram. Results suggest the mobile commerce needs to be handled differently from the traditional electronic commerce.

• Korean Journal of Optics and Photonics
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• v.17 no.3
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• pp.278-284
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• 2006

We have fabricated and measured electrooptic modulator using coupled stack InAs/InGaAs quantum dots. The height of the quantum dot is 16 nm and quantum dots are stacked including an InGaAs capping layer. The peak wavelength of photoluminescence is 1260 nm at room temperature and 1158 nm at 12 K. The operation characteristics of the quantum dots show high modulation efficiency of electrooptic modulator at 1550 nm compared to that of existing III-V bulk and MQW type semiconductor. The measured switching voltage ($V\pi$) is 540 and 600 mV, for TE mode and TM mode, respectively. From the results, the modulation efficiency can be determined as 333.3 and $300^{\circ}/V{\cdot}mm$ for TE and TM modes. The results reported here may lead to the design and fabrication of a novel electrooptic modulator with low switching voltage and high efficiency.

• Food Science and Preservation
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• v.11 no.2
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• pp.250-256
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• 2004

The objectives of this study were to develop a new commercial grain cooler suited to domestic weather and post-harvesting conditions for paddy, and to evaluate the performance. A prototype grain cooler capable of cooling paddy of 200 tons within 24 hours was developed. The grain cooler was designed to control the refrigeration capacity from 0 to 100% by controlling the capacity of compressor with unloading solenoid valve and by changing the flow rates of hot refrigerant gas flowing into reheater and evaporator from compressor. And a controller with one chip microprocessor was developed to control temperature and relative humidity of cooling air. The maximum cooling capacity of the grain cooler was 35,284㎉/hr at condensing/evaporating pressure of 16.5/3.6 kgf/$\textrm{cm}^2$. Maximum flow rate of cooling air was 120 ㎥/min at static pressure of 279 mmAq. The total maximum required power was 22.8㎾, and total required energy was saved from 26.7 to 33.3% of maximum power depending on operating conditions. The coefficient of performance of refrigeration devices and total coefficient of performance of the grain cooler were 4.71 and 1.8, respectively.

• Korean Journal of Plant Resources
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• v.28 no.5
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• pp.665-674
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• 2015

The final goal of this research is to develop a botanical biofiltration system, which combines green interior, biofiltering, and automatic irrigation, which can purify indoor air pollutants according to indoor space and the size of biofilter. The biofilter used in this experiment was designed as an integral form of water metering pump, water tank, blower, humidifier, and multi-level planting space in order to be more suitable for indoor space utilization. This study was performed to compare indoor air quality between the space adjacent to a botanical biofilter and the space away from the biofilter (control) without generation of artificial indoor air pollutants, and to evaluate plant growth depending on multiple floors within the biofilter. Each concentration of indoor air pollutants such as TVOCs, monoxide, and dioxide in the space treated with the biofilter was lower than that of control. Dracaena sanderiana ‘Vitoria’ and Epipremnum aureum ‘N Joy’ also showed normal growth responses regardless of multiple floors within the biofilter. Hence, it was confirmed that the wall-typed botanical biofilter suitable for indoor plants was effective for indoor air purification.

• The Journal of the Korea Contents Association
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• v.18 no.6
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• pp.353-363
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• 2018

According to the Digi Capital forecast, the global augmented reality market is expected to grow rapidly by 2020 to reach 150 billion dollars. In particular, high value added effects are expected in education. As ICT advances, digital textbooks are also leading innovative education by adding interactive functions. Advanced countries, including the U.S., are already using digital textbooks that use augmented reality technology in their classes. In line with this technological outlook, the ministry proposed a design plan that applies augmented reality technology to middle school science 1 digital textbooks. A study on middle school science 1 digital textbooks showed that each unit provided short videos. In addition, an investigation into the augmented reality class case showed that it was difficult to establish experimental equipment, lack of equipment (devices), and 3D design contents that did not continue despite the excellence of learning effects. Based on this demand, we designed an augmented reality scenario and system configuration to be applied to the instrument-specific experiments of middle school science 1 digital textbooks to explore and explore the contents of augmented reality by students. This research will replace the dangerous experiments and time consuming experiments for teachers and students by applying augmented reality to science subjects that are essential for the development of digital textbooks.