• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.8
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• pp.759-769
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• 2013

Electronic equipment has been applied to virtually every area associated with commercial, industrial, and military applications. Specifically, electronics have been incorporated into avionics components installed in aircraft. This equipment is exposed to dynamic loads such as vibration, shock, and acceleration. Especially, avionics components installed in a helicopter are subjected to simultaneous sine and random base excitations. These are denoted as sine on random vibrations according to MIL-STD-810F, Method 514.5. In the past, isolators have been applied to avionics components to reduce vibration and shock. However, an isolator applied to an avionics component installed in a helicopter can amplify the vibration magnitude, and damage the chassis, circuit card assembly, and the isolator itself via resonance at low-frequency sinusoidal vibrations. The objective of this study is to investigate the dynamic characteristics of an avionics component installed in a helicopter and the structural dynamic modification of its tray plate without an isolator using both a finite element analysis and experiments. The structure is optimized by dynamic loads that are selected by comparing the vibration, shock, and acceleration loads using vibration and shock response spectra. A finite element model(FEM) was constructed using a simplified geometry and valid element types that reflect the dynamic characteristics. The FEM was verified by an experimental modal analysis. Design parameters were extracted and selected to modify the structural dynamics using topology optimization, and design of experiments(DOE). A prototype of a modified model was constructed and its feasibility was evaluated using an FEM and a performance test.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.2
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• pp.67-75
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• 2012

Carbon-dioxide capture and storage (CCS) process is consisted by capturing carbon-dioxide from large point source such as power plant and steel works, transporting and sequestrating captured $CO_2$ in a stable geological structure. During CCS process, it is inevitable of introducing impurities from combustion, capture and purification process into $CO_2$ stream. Impurities such as $SO_2$, $H_2O$, CO, $N_2$, Ar, $O_2$, $H_2$, can influence on process efficiency, capital expenditure, operation expense of CCS process. In this study, experimental apparatus is built to simulate the behavior of $CO_2$ transport under various impurity composition and process pressure condition. With this apparatus, $N_2$ impurity effect on $CO_2$ mixture transportation was experimentally evaluated. The result showed that as $N_2$ ratio increased pressure drop per mass flow and specific volume of $CO_2-N_2$ mixture also increased. In 120 and 100 bar condition the mixture was in single phase supercritical condition, and as $N_2$ ratio increased gradient of specific volume change and pressure drop per mass flow did not change largely compared to low pressure condition. In 70 bar condition the mixture phase changed from single phase liquid to single phase vapor through liquid-vapor two phase region, and it showed that the gradient of specific volume change and pressure drop per mass flow varied in each phase.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.3
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• pp.187-197
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• 2010

Carbon dioxide Capture and Storage(CCS) is regarded as one of the most promising options to response climate change. CCS is a three-stage process consisting of the capture of carbon dioxide($CO_2$), the transport of $CO_2$ to a storage location, and the long term isolation of $CO_2$ from the atmosphere for the purpose of carbon emission mitigation. Up to now, process design for this $CO_2$ marine geological storage has been carried out mainly on pure $CO_2$. Unfortunately the $CO_2$ mixture captured from the power plants and steel making plants contains many impurities such as $N_2$, $O_2$, Ar, $H_2O$, $SO_2$, $H_2S$. A small amount of impurities can change the thermodynamic properties and then significantly affect the compression, purification, transport and injection processes. In order to design a reliable $CO_2$ marine geological storage system, it is necessary to analyze the impact of these impurities on the whole CCS process at initial design stage. The purpose of the present paper is to compare and analyse the relevant physical property models including BWRS, PR, PRBM, RKS and SRK equations of state, and NRTL-RK model which are crucial numerical process simulation tools. To evaluate the predictive accuracy of the equation of the state for $CO_2-SO_2$ mixture, we compared numerical calculation results with reference experimental data. In addition, optimum binary parameter to consider the interaction of $CO_2$ and $SO_2$ molecules was suggested based on the mean absolute percent error. In conclusion, we suggest the most reliable physical property model with optimized binary parameter in designing the $CO_2-SO_2$ mixture marine geological storage process.

• Food Science and Preservation
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• v.14 no.3
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• pp.288-293
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• 2007

Intermediate moisture-apple snail products were prepared by adding glycerol, sorbitol, kiwi, or pineapple(2% or 5% w/w), as tenderizers, and by drying at $4^{\circ}C$ for 24 hr. The effects of the tenderizers on textural and sensory properties of the apple snail products at intermediate moisture levels were investigated. Moisture content and water activity of the products were ranged from 26.25 to 34.48% and from 0.83 to 0.87, respectively. The addition of glycerol significantly lowered water activity of apple snail samples compared to control prepared without tenderizers. On the other hand, significant increases in moisture content and water activity were observed in apple snail samples treated with kiwi or pineapple(p<0.05). All apple snail samples treated with tenderizers showed a lower shear force than did the control. Apple snail samples treated with 5%(v/v) glycerol showed a higher equilibrium moisture content than did the other samples. SDS-PAGE indicated that proteolytic enzymes in kiwi and pineapple clearly changed the structure of the myosin heavy chain and actin filaments of myofibrillar protein in apple snail samples. Intermediate moisture apple snail samples treated with tenderizers showed significantly improved overall sensory characteristics. The highest overall acceptability was obtained from apple snail samples treated with 5% pineapple, while the lowest overall acceptability was noted in the control sample. This study demonstrates that an acceptable apple snail, with intermediate moisture content, may be produced by using tenderizers at appropriate concentrations.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.1
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• pp.18-29
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• 2010

Offshore subsurface storage of $CO_2$ is regarded as one of the most promising options to response severe climate change. Marine geological storage of $CO_2$ is to capture $CO_2$ from major point sources, to transport to the storage sites and to store $CO_2$ into the offshore subsurface geological structure such as the depleted gas reservoir and deep sea saline aquifer. Since 2005, we have developed relevant technologies for marine geological storage of $CO_2$. Those technologies include possible storage site surveys and basic designs for $CO_2$ transport and storage processes. To design a reliable $CO_2$ marine geological storage system, we devised a hypothetical scenario and used a numerical simulation tool to study its detailed processes. The process of transport $CO_2$ from the onshore capture sites to the offshore storage sites can be simulated with a thermodynamic equation of state. Before going to main calculation of process design, we compared and analyzed the relevant equation of states. To evaluate the predictive accuracies of the examined equation of states, we compare the results of numerical calculations with experimental reference data. Up to now, process design for this $CO_2$ marine geological storage has been carried out mainly on pure $CO_2$. Unfortunately the captured $CO_2$ mixture contains many impurities such as $N_2$, $O_2$, Ar, $H_{2}O$, $SO_{\chi}$, $H_{2}S$. A small amount of impurities can change the thermodynamic properties and then significantly affect the compression, purification and transport processes. This paper analyzes the major design parameters that are useful for constructing onshore and offshore $CO_2$ transport systems. On the basis of a parametric study of the hypothetical scenario, we suggest relevant variation ranges for the design parameters, particularly the flow rate, diameter, temperature, and pressure.

• Journal of Korean Society of Disaster and Security
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• v.10 no.2
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• pp.7-19
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• 2017

Recently, the incidence of disasters and safety incidents is increasing rapidly, and the interest and demands of the people are increasing. In particular, traffic accidents in Korea are decreasing due to the continuous efforts of the government and the local governments, but still higher than the OECD average. In response to such demands of the times, the 'Regional Safety Index', a numerical value that quantifies the level of safety of each local government, is being publicized every year to awaken public awareness. The Regional Safety Index covers seven categories of accidents (traffic accidents, crimes, suicide, infectious diseases, fire, safety accidents, and natural disasters) in local governments. But, this study focuses on the traffic accident area and analyzed. The target local government is Ulju county of Ulsan Metropolitan City. Based on the traffic accident statistical data of Ulju county, the analysis of the traffic accidents and vulnerable points were analyzed. Among them, 3 key improvement districts were selected and 15 vulnerable branches were selected for each key improvement district. Next, we prepared measures for improvement of each accident vulnerable site through analysis of geographic information through traffic data related to traffic accidents and interview with related organizations. In addition, the improvement measures are divided into the structural infrastructure improvement, the institutional improvement, and the traffic safety culture movement from the viewpoint of traffic accident prevention. Finally, the implications of this study are to clarify the duties and roles of the relevant departments in the municipality, based on the implementation schedule of the improvement projects for the prevention of traffic accidents and the budget plan. In addition, it is very important that the participating agencies involved in traffic accidents and the private sector participate in the project.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.41 no.1
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• pp.47-55
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• 2023

In this study, the following conclusions were drawn by analyzing the size, proportion, shape, angle, distribution, etc. of stones in order to identify the principles of facade molding of stonework of the 5th to 7th centuries of the Silla Dynasty. First, the uniformity of the size of the stones of the stone foundations of the Silla Dynasty was low at -0.8 to 4.1. This means that stones of various sizes were used, from small stones to large stones. In addition, the distribution of large stones in stonework of the Silla Dynasty appeared evenly regardless of height. This was common in the stonework of the Silla Dynasty, regardless of structural classification such as wells and mountain fortresses. It is thought that the Silla people did not only pursue practicality and efficiency in stone construction, but also considered design elements. Second, the proportional deviation of the stones of the stone walls of the Silla Dynasty was high, ranging from 0.861 to 1.515. This means that the stonework of the Silla Dynasty did not use only long flagstone-shaped stones, but used a mixture of long and short stones. Third, the shape average of the stones of the stonework of the Silla Dynasty was low at 0.45, and the shape deviation was high at the maximum of 0.15. This means that the stones as a whole have irregular shapes, and each stone has a high difference in shape. Fourth, the angle deviation of the stones of the Silla Dynasty was 4.3 to 16.2, and the average angle was 2. This means that the angle of each stone on the stone axis of the Silla Dynasty is tilted to the left and right. Fifth, there was no correlation between stone size, slenderness ratio, shape, and angle in the stone axes of the Silla Dynasty. In the case of stone axes in the Joseon Dynasty, there was a positive correlation between stone size and slenderness, and a negative correlation between stone size and shape. It can be said that the stones of the Joseon Dynasty were relatively standardized, but the Silla Dynasty showed the beauty of moderation by keeping the nature of the material and becoming one with the material.

• Asia Marketing Journal
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• v.11 no.3
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• pp.185-203
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• 2009

Yuhan Kimberly, a joint-venture company of Korean Yuhan Company and American Kimberly-Clark, opened a premium diaper market in Korea by launching Pull-Ups which was pants-typed diapers in 1993. Pull-Ups was imported as finished goods from Kimberly-Clark. However, in spite of its huge market share in United States, it failed to land down in Korean market because of wrong positioning strategy which did not consider domestic customers' tastes. In 1996, Yuhan-Kimberly brought out a pants-typed diaper, Huggies-Toddler, to Korean market again. This paved the way for the combination of Kimberly-Clark's production power and Yuhan-Kimberly's marketing power and led to launch new product superior to Pull-Ups. However, this product was unsuccessful in the market because of wrong positioning which did not catch domestic customer's life styles such as cultural, environmental and habitual differences in toilet training, the cost increase coming from IMF crisis in Korea, weak trust within the company, weak trust within the company, and too much higher price than regular diapers. In 2005, Yuhan-Kimberly redeveloped new pants market business strategy. It was organically combined with winning product development plan, winning communication strategy and the market structure change through the pants market creation. Customer's habit, usage and attitude were studied with total 55 times market investigations. Also, all processes from planning to designing were executed in the customer's view by investigating product research, positioning research and advertisement research. Yuhan-Kimberly repositioned new product as a wearing diaper not as a toilet training diaper and launched Huggies Magic Panty as a premium product which had 25% higher price than previous Huggies. Huggies Magic Panty was recognized as a great hit product in domestic diaper market and the sales recorded 37.6 bill won in 2006, 57.2 bill won in 2007, and 90 bill won in 2008 since launching in 2005. The reason of Huggies Magic Panty's success was the repositioning strategy deduced from the precise check of customer's usage habit. It was the winning strategy of Huggies that were market investigation in order to survive in domestic baby goods market where a lot of companies struggled intensively, the exact positioning based on its market investigation and aggressive 360 degree communication strategy to give customers impressions efficiently.

• Journal of The Korean Association For Science Education
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• v.44 no.1
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• pp.11-27
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• 2024

This study aimed to investigate the role of scientific empathy in influencing students' productive disciplinary engagement in scientific activities and analyze the key factors of scientific empathy that manifest during this process. Twelve fifth-grade students were divided into three subgroups based on their general empathic abilities. Lessons promoting productive disciplinary engagement, integrating design thinking processes, were conducted. Subgroup discourse analysis during idea generation and prototype stages, two of five problem-solving steps, enabled observation of scientific empathy and practice aspects. The results showed that applying scientific empathy effectively through design thinking facilitated students' productive disciplinary engagement in science. In the idea generation stage, we observed an initial increase followed by a decrease in scientific empathy and practice utterances, while during the prototyping stage, utterance frequency increased, particularly in the later part. However, subgroups with lower empathic abilities displayed decreased discourse frequency in scientific empathy and practice during the prototype stage due to a lack of collaborative communication. Across all empathic ability levels, the students articulated all five key factors of scientific empathy through their utterances in situations involving productive science engagement. In the high empathic ability subgroup, empathic understanding and concern were emphasized, whereas in the low empathic ability subgroup, sensitivity, scientific imagination, and situational interest, factors of empathizing with the research object, were prominent. These results indicate that experiences of scientific empathy with research objects, beyond general empathetic abilities, serve as a distinct and crucial factor in stimulating diverse participation and sustaining students' productive engagement in scientific activities during science classes. By suggesting the potential multidimensional impact of scientific empathy on productive disciplinary engagement, this study contributes to discussions on the theoretical structure and stability of scientific empathy in science education.