• Strategy21
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• s.41
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• pp.261-293
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• 2017

Nuclear power is a way of attaining an enormous amount of energy with relatively small amount of resources and after it has been introduced to the submarine since 1954, there are approximately 150 of nuclear powered submarine currently on a mission around the world. This is due to the maneuverability, mountability and covertness of nuclear submarines. However, there are other tasks, not only the high level of nuclear technology that are needed to be dealt with in order to construct nuclear powered submarine. The biggest task of all is to secure the enriched uranium. Accordingly, this research is about the way of enriching and securing the nuclear fuel that are used in the nuclear submarine with the characteristics, merits and demerits of the nuclear submarine. Due to the fact that the pressurized water reactor in South Korea is the reactor that was originally built for the development of nuclear powered submarine, many parts is designed to be suitable for the submarine propulsion. However, in order to apply this to submarine it is needed to consider additional requests such as the position of reactor, accident-coping system, radioactive covering, reactor output adjustment and ship's pitch and roll in order to apply this to submarine. Nuclear submarines have much higher speed based on the powerful propulsion in comparison with diesel-electric submarine and also have bigger loading area. Besides, there is no need to snorkel and they also have advantages in covertness with the multi-noise proof system. The nuclear technology in South Korea has seen the dramatic development since 1962 and in 1998 reached to the level that we have succeeded in the localization of nuclear plant and exported the world-class one-piece small-sized reactor (SMART) to UAE. To operate these reactors, we import the whole quantity of low-enriched uranium and having our own uranium enrich facility is not probable because of the budget and international regulations. With the ROK/US nuclear agreement revised on 2015 November, the enrichment of uranium that are available without special permission has changed up to 20%. According to the assumption that we use the 20% enrichment of Uranium on U.S. virginia class submarine, it is necessary to change the fuel after 11 years and it will cause additional cost of 1 billion dollars. But the replace period by the uranium's enrichment rate is not fixed so that it is possible to change according to the design of reactor. Therefore, I would like to make a suggestion on two types of design concepts of nuclear submarine that can be operated for 30 years without nuclear fuel change by using the 20% enriched uranium from ONNp.First of all, it is possible by increasing the size of reactor by 3 times and it results in the 1,000t increase of the weight. And secondly, it is by designing the one piece reactor to insert devices such as steam turbine, condenser into the inside of nuclear core like the Rubis class submarines of France.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.7
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• pp.52-60
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• 2010

In this paper, we propose a dynamic power management framework for multi-core systems. We reduced the power consumption of multi-core processors such as Intel Centrino Duo and ARM11 MPCore, which have been used at the consumer electronics and personal computer market. Each processor uses a different technique to save its power usage, but there is no embedded multi-core processor which has a precise power control mechanism such as dynamic voltage scaling technique. The proposed dynamic power management framework is suitable for smart phones which have an operating system to provide multi-processing capability. Basically, our framework follows an intuitive idea that reducing the power consumption of idle cores is the most effective way to save the overall power consumption of a multi-core processor. We could minimize the energy consumption used by idle cores with application-targeted policies that reflect the characteristics of active workloads. We defined some properties of an application to analyze the performance requirement in real time and automated the management process to verify the result quickly. We tested the proposed framework with popular processors such as Intel Centrino Duo and ARM11 MPCore, and were able to find that our framework dynamically reduced the power consumption of multi-core processors and satisfied the performance requirement of each program.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.9
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• pp.1143-1150
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• 2017

The aim of this study was to determine the chemical and intracellular antioxidant activities of ${\beta}$-carotene and lycopene and to compare their quantitative structure-activity relationship (QSAR). In our previous study, the second ionization energy of lycopene was higher than that of ${\beta}$-carotene, as calculated by QSAR. Chemical antioxidant activities of ${\beta}$-carotene, lycopene, and Trolox were examined by measuring ferric reducing antioxidant power (FRAP) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Intracellular antioxidant activities were evaluated by intracellular reactive oxygen species (ROS) and DNA fragmentation. The FRAP of lycopene was higher than that of ${\beta}$-carotene (P<0.05), and the two carotenoids had similar antioxidant activities in DPPH radical scavenging activity assay. Trolox had the greatest chemical antioxidant activities (P<0.05). When RAW264.7 cells were treated with lipopolysaccharide (LPS) (100 ng/mL) for 20 h, intracellular ROS and DNA fragmentation significantly increased (P<0.05). RAW 264.7 cells pretreated with ${\beta}$-carotene ($4{\mu}M$) and lycopene ($0.4{\sim}2{\mu}M$) for 4 h formed significantly less intracellular ROS than LPS-treated control cells (P<0.05), whereas cells with Trolox did not reduce production of intracellular ROS. In addition, cells pretreated with $2{\mu}M$ lycopene produced less intracellular ROS than those treated with ${\beta}$-carotene (P<0.05). DNA fragmentation of cells with ${\beta}$-carotene and lycopene was similar to that of LPS-treated control cells as measured by Hoechst staining. The antioxidant ability of lycopene was greater than that of ${\beta}$-carotene in the QSAR, FRAP, and intracellular ROS assays (P<0.05). ${\beta}$-Carotene and lycopene had lower antioxidant activities as measured by FRAP (P<0.05) but higher intracellular protective effects against LPS-induced oxidative stress in comparison with Trolox.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.80-87
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• 2018

In recent years, due to the spread of various renewable energy power sources and the pursuit of high efficiency and low-power consumption, not only trends in the electric power industry but also the consumption, control methods, and characteristics are diversified. However, in this diversified electric power industry, the fuse (which is the core part responsible for safety) has not developed significantly in classical operation mode, and thus, fires continue to occur. In this paper, the effects of low melting-point metal plating and high melting-point metal plating on operating characteristics and IT curve movement of the fuse are investigated in a cartridge fuse, which is a classic fuse manufacturing method. The effects of plating on the thickness of the fuse are investigated, and various operating characteristics of the fuse are implemented. In addition, it is suggested that the plating of the low melting-point metal moves the rated current line of the fuse to a low rating, and moves operating characteristics to characteristics of delay operation. It is possible to design various operating characteristics using this characteristic.

• Journal of Engineering Education Research
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• v.18 no.3
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• pp.46-58
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• 2015

Informal engineering education program for high school students was developed to cultivate engineering literacy using the human resources and facilities of university. Plant factory, a smart farming technology, was selected as a main theme, and the novel engineering camp program involving engineering design activities and intra-linter-team works was planned. The camp program was applied to 38 high school students in an active learning classroom. Five teams were constructed according to elemental technologies such as biotechnology, information-communication technology, energy engineering, mechanical engineering and architectural engineering, and the students were participated in intra- and inter-team activities to achieve the final goal of 'the construction of a plant factory in school'. The team works were conducted according to the eight steps of engineering design process (identifying the problem and need, identifying criteria and constraints, brainstorming possible solutions, selecting the best possible solution, constructing a prototype, testing and evaluating the solution, communicating the solution, and refining design). Participants' satisfaction survey showed that the satisfaction on the contents of engineering design was 4.48 on 5-point Likert scale. The participants' satisfaction on creative activity and systematic methodology was 4.43 on 5-point Likert scale. 97% of participants responded positively to team works, and 92% of participants were satisfied with career mentoring activity supplied by undergraduate/graduate students. These results indicates that the engineering camp program involving engineering design activity and intra-/inter-team works can contribute to cultivate engineering literacy such as creativity, problem solving ability, collaboration, communication skills for high school students, and to increase their interests in engineering fields.

• Membrane Journal
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• v.30 no.3
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• pp.190-199
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• 2020

The utilization of multiple water sources becomes important due to the master plan for development of water supply released by Ministry of Environment, Korea in 2018. In this study, therefore, the analysis of comprehensive effect in blending applicable water sources in Daesan where 100,000 ㎥/d seawater desalination plant will be constructed for industrial use was performed. The increase in mixing ratio of other water sources with seawater reduced salinity up to 50%, but negatively impacted the turbid and organic matter. Lab-scale reverse osmosis performance test also found that membrane fouling was exacerbated in blended water condition. The simulation results of reverse osmosis indicated 39% energy saving on average is expected at the one-to-one blending ratio, however, long-term performance test at the pilot-scale plant is highly required to evaluate the inclusive impact of mixing seawater and other water sources.

• Clean Technology
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• v.18 no.3
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• pp.301-306
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• 2012

Rapidly growing mobile machines such as tablet PC and smart phone are equipped with touch screen panel using a sturdy material for products surface protection. Therefore, surge of chemically strengthened glass was increased and the amount of waste matter is proportional to demand. The purpose of this study is environmental impact assessment on touch screen panel of chemically strengthened glass by material life cycle assessment (MLCA). We used CES of Granta, SimaPro and Gabi software for MLCA. Chemically strengthened glass (2.7, 5.7 and 10.3 inch) was calculated to environmental impact assessment by Granta software under two cases. One case is Landfill and the other case is Reuse. As a result, in case of reuse, energy values of 2.7, 5.7 and 10.3 inches were reduced by an average of 51.4%, $CO_2$ values were reduced by an average of 46.6% than Landfill case, respectively. We assessed impact categories of 11 types using SimaPro software. As a result, the contents of fossil fuels, inorganics and climate change have a huge impact than the other impact categories. And the main cause of environmental impact is antimony and hydrogen fluoride in Gabi results.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.616-621
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• 2017

The objective of this study was to investigate the physicochemical properties of domestic strong wheat flour (DSWF). Three commercial DSWFs (D1, D2, and D3) were compared with imported strong wheat flour (ISWF). DSWFs had higher moisture content, crude protein content, lightness, and whiteness than ISWF. DSWFs showed lower solvent retention capacity and water absorption index than ISWF. DSWFs also showed significantly higher water solubility index than ISWF (P<0.05). Setback values by rapid visco analysis were significantly higher in D1 and D2 than in ISWF and D3, which means ISWF and D3 were better in retarding retrogradation. Differential scanning calorimetry results showed that ISWF required 6.2 J/g of energy for phase transition, whereas DSWFs needed 6.67~7.13 J/g. The farinograph results showed that ISWF had higher water absorption, longer dough stability time, and significantly higher softening of dough at 20 min than DSWF (P<0.05). Dough resistance and extensibility were higher in ISWF than in DSWFs.

• KIPS Transactions on Software and Data Engineering
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• v.7 no.4
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• pp.129-134
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• 2018

Recently, the artificial neural network (ANN) model is a promising technique in the prediction, numerical control, robot control and pattern recognition. We predicted the outside temperature of greenhouse using ANN and utilized the model in greenhouse control. The performance of ANN model was evaluated and compared with multiple regression model(MRM) and support vector machine (SVM) model. The 10-fold cross validation was used as the evaluation method. In order to improve the prediction performance, the data reduction was performed by correlation analysis and new factor were extracted from measured data to improve the reliability of training data. The backpropagation algorithm was used for constructing ANN, multiple regression model was constructed by M5 method. And SVM model was constructed by epsilon-SVM method. As the result showed that the RMSE (Root Mean Squared Error) value of ANN, MRM and SVM were 0.9256, 1.8503 and 7.5521 respectively. In addition, by applying the prediction model to greenhouse heating load calculation, it can increase the income by reducing the energy cost in the greenhouse. The heating load of the experimented greenhouse was 3326.4kcal/h and the fuel consumption was estimated to be 453.8L as the total heating time is $10000^{\circ}C/h$. Therefore, data mining technology of ANN can be applied to various agricultural fields such as precise greenhouse control, cultivation techniques, and harvest prediction, thereby contributing to the development of smart agriculture.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.369-377
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• 2013

This paper deals with the state of charge(SOC) and life cycle evaluation algorithm for lead-acid battery, which is essential factor of the electric vehicle(EV) and the stabilization of renewable energy in the smart grid. In order to perform the effective operation of the lead-acid battery, SOC and life cycle evaluation algorithm is required. Specific gravity with the change of electrolyte temperature inside battery case should be obtained to evaluate the SOC of lead-acid battery, however it is difficult to measure the electrolyte temperature of sealed type lead-acid battery. To overcome this problem, this paper proposes the equation of thermal transmission to compensate internal temperature of the lead-acid battery. Also, it is difficult to exactly evaluate the life cycle of battery, depending on the operation conditions of lead-acid battery such as charging and discharging state, self discharging rate and environmental issue. In order to solve the problem, this paper presents the concept for gravity accumulation of charge and discharge cycle, which is the value converted at $20^{\circ}C$. By using the proposed algorithm, this paper propose the test device based on the Labview software. The simulation results show that it is a practical tool for the maintenance of lead-acid battery in the field of industry.