• New Physics: Sae Mulli
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• v.68 no.11
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• pp.1183-1191
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• 2018

The plasmon behaviors in a superlattice of $GaAs/Al_xGa_{1-x}As$ multiple quantum wells with a half-parabolic confining potential due to different dielectric interfaces are studied under magnetic and electric fields perpendicular and parallel to the superlattice axis by using a previously published theoretical framework. From the density-density correlation functions by considering the intrasubband and the inter-subband transitions under the random phase approximation, we calculate the dispersion energies of the surface and the bulk states as functions of the composition of the multiple quantum well structure and of the magnetic field strength and the average electric field strength over the quantum well. The Raman intensities for various magnetic field strengths and average electric field strengths over the quantum well are also obtained as a function of the energy of the incoming light for these states.

• Korean Journal of Remote Sensing
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• v.38 no.5_3
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• pp.811-818
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• 2022

Recently, the number of natural and environmental disasters is rapidly increasing due to extreme weather caused by climate change, and the scale of economic losses and damage to human life is increasing accordingly. In addition, with urbanization and industrialization, the characteristics and scale of extreme weather appearance are becoming more complex and large in different ways from the past, and need for remote sensing and artificial intelligence technology for responding and managing global environmental disasters. This special issue investigates environmental disaster observation and management research using remote sensing and artificial intelligence technology, and introduces the results of disaster-related studies such as drought, flood, air pollution, and marine pollution, etc. in South Korea performed by the i-SEED (School of Integrated Science for Sustainable Earth and Environmental Disaster at Pukyong National University). In this special issue, we expect that the results can contribute to the development of monitoring and management technologies that may prevent environmental disasters and reduce damage in advance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.144-150
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• 2013

From ancient times to the present day, naval warfare in history is deeply connected with the rise and fall of countries. This study examines which countries won wars by tracing naval warfare that they had carried out. Seven Cases are traced for the analysis including the battle of Salamis and the Poeni War in the ancient period, the battle of Calais in the medieval and modern periods, the Russo-Japanese War in the modern period, and the Falklands War in the present age. The results show three fundamental characteristics. First, countries that won naval warfare were armed with the state-of-the-art weapon systems and conducted joint operations effectively. Second, countries that fought in the usual ways were defeated by challengers. Third, countries such as Athens, Rome, Britain and the United States ascended to the hegemony by winning major naval warfare and then commanding or controlling the sea at their own free will. Countries defeated in these naval warfare, however, descended to the weak powers. In general, countries that won warfare have a tendency to make light of defeated countries, not to introduce new weapon systems from abroad, and to stick to their traditional ways of fighting. These lessons indicate that the ROK military needs to continue the development of new weapon systems at peacetime. In addition, they show that it needs to focus more on the articulation of military doctrines and training systems so that warriors on the battlefield can fight better.

• Journal of the Korean earth science society
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• v.43 no.6
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• pp.691-711
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• 2022

The state-of-the-art Earth system model as a virtual Earth is required for studies of current and future climate change or climate crises. This complex numerical model can account for almost all human activities and natural phenomena affecting the atmosphere of Earth. The Unified Model (UM) from the United Kingdom Meteorological Office (UK Met Office) is among the best Earth system models as a scientific tool for studying the atmosphere. However, owing to the expansive numerical integration cost and substantial output size required to maintain the UM, individual research groups have had to rely only on supercomputers. The limitations of computer resources, especially the computer environment being blocked from outside network connections, reduce the efficiency and effectiveness of conducting research using the model, as well as improving the component codes. Therefore, this study has presented detailed guidance for installing a new version of the UM on high-performance parallel computers (Linux clusters) owned by individual researchers, which would help researchers to easily work with the UM. The numerical integration performance of the UM on Linux clusters was also evaluated for two different model resolutions, namely N96L85 (1.875° ×1.25° with 85 vertical levels up to 85 km) and N48L70 (3.75° ×2.5° with 70 vertical levels up to 80 km). The one-month integration times using 256 cores for the AMIP and CMIP simulations of N96L85 resolution were 169 and 205 min, respectively. The one-month integration time for an N48L70 AMIP run using 252 cores was 33 min. Simulated results on 2-m surface temperature and precipitation intensity were compared with ERA5 re-analysis data. The spatial distributions of the simulated results were qualitatively compared to those of ERA5 in terms of spatial distribution, despite the quantitative differences caused by different resolutions and atmosphere-ocean coupling. In conclusion, this study has confirmed that UM can be successfully installed and used in high-performance Linux clusters.

• Journal of the Korean earth science society
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• v.41 no.5
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• pp.490-503
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• 2020

Oceanic current and circulation have played an important role as regulators of the earth's energy distribution. The science and earth science textbooks for secondary schools based on the 2015 revised curriculum included a misconception of the seasonal variation of the North Korea Cold Current (NKCC) among the currents around the Korean Peninsula. To analyze this, the contents related to the NKCC were collected in the textbooks of five middle and six high schools, and a questionnaire survey was conducted on 30 middle school science teachers. The survey consisted of questions about whether the textbook mentions the NKCC and whether there is an error in the concept of the temporal variation of the NKCC, and the teachers' free opinions related to the NKCC were collected. The textbooks suggest that the NKCC is strongest in winter, which is not consistent with scientific findings so far. In fact, there is scientific evidence that the NKCC is the strongest in the summer. In this study, the causes and processes of misconceptions were investigated. According to an analysis of the survey, most teachers had an knowledge that the NKCC is stronger in winter. These errors began with a misconception of the terms, which teachers had imprinted on their memory as firm knowledge. These misconceptions originated from the knowledge that teachers themselves acquired from their secondary school years and have long been transferred back to teachers and students without revising the misconceptions of textbooks. This situation is expected to have a seriously recurrent structure that produces students' serious misconceptions in the future. Therefore, this study summarizes existing results on the seasonal variability of the NKCC and suggests the necessity for re-education to improve teachers' professionalism and to eliminate the misconceptions of teachers and students.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.60-76
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• 2022

This study presents a software full setup and the following test execution times in a Linux cluster for the United Kingdom Earth System Model (UKESM) and then compares the model results from control and experimental simulations of the UKESM relative to various observations. Despite its low resolution, the latest version of the UKESM can simulate tropospheric chemistry-aerosol processes and the stratospheric ozone chemistry using the United Kingdom Chemistry and Aerosol (UKCA) module. The UKESM with UKCA (UKESM-UKCA) can treat atmospheric chemistryaerosol-cloud-radiation interactions throughout the whole atmosphere. In addition to the control UKESM run with the default CMIP5 SO₂ emission dataset, an experimental run was conducted to evaluate the aerosol effects on meteorology by changing atmospheric SO₂ loading with the newest REAS data over East Asia. The simulation period of the two model runs was 28 years, from January 1, 1982 to December 31, 2009. Spatial distributions of monthly mean aerosol optical depth, 2-m temperature, and precipitation intensity from model simulations and observations over East Asia were compared. The spatial patterns of surface temperature and precipitation from the two model simulations were generally in reasonable agreement with the observations. The simulated ozone concentration and total column ozone also agreed reasonably with the ERA5 reanalyzed one. Comparisons of spatial patterns and linear trends led to the conclusion that the model simulation with the newest SO₂ emission dataset over East Asia showed better temporal changes in temperature and precipitation over the western Pacific and inland China. Our results are in line with previous finding that SO₂ emissions over East Asia are an important factor for the atmospheric environment and climate change. This study confirms that the UKESM can be installed and operated in a Linux cluster-computing environment. Thus, researchers in various fields would have better access to the UKESM, which can handle the carbon cycle and atmospheric environment on Earth with interactions between the atmosphere, ocean, sea ice, and land.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.12
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• pp.425-435
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• 2018

The purpose of this study is to investigate the cultural value as well as business value of Juk-Bang-Ryeum(fishing instrument made by bamboo weir) by the investigation of remains in Gyeongnam Sacheon area and reviewing various historical literatures. The research will contribute to make back data necessary for the registration of World Heritage(UNESCO) and Globally Important Agricultural Heritage Systems(FAO). Fisheries, along with agriculture, have been great significance in human history. In particular, the Fisheries has been considered very important industry due to the geopolitical characteristics of our country surrounded by the sea. We can imagine may types of fishing practices and instruments at the agricultural age. Nonetheless, there are a few fishery heritages such as collecting and hunting tools that remains today. Fortunately, there are many Juk-Bang-Ryeum which is actually operate now from the past 500 years ago at the The Sacheon and Namhae areas. We could found some literature records about it in the historical ancient literatures. We could also infer that Juk-Bang-Ryeum was an important fishery resource of the country for a long time. It was built on the basis of scientific principles to capture fishes using the rapid tide of the natural geological straits, and it prove the wisdom of our ancestors. We also could found some unique cultural heritages that was important to the local community. Naturally, it has been managed as an important asset for the residents. In addition to such historical and humanistic values, it also has business and educational value. It can be useful to understand scientific fishery principles as well as fishery experience field. It has business value as an important tourism resource in the region in connection with historical relics and geological environment resources. In conclusion, it is a valuable asset to be handed down as a valuable cultural heritage.

• Journal of Fisheries and Marine Sciences Education
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• v.19 no.2
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• pp.197-205
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• 2007

This study was to investigate the chemical content and antioxidant activity by the part of Salicornia herbacea as part of using Salicornia herbacea as materials of functional foods. On a basis of the materials, this study was to clarify the nutritional excellence, chemical composition, and antioxidant activity of Salicornia herbacea. From the result of this research above, it may be summed up as follows.The Salicornia herbacea used in the experiment contained the moisture and crude fiber in the stalks a lot, and the protein, fat, and ash in the branches more. As to the content of free amino acid, the content of arginine took in the branches and stems most. Then, it contained threonine, glycine, tryptophan, valine, isoleucine, and lysine, etc. in the branches a lot. Also, it contained threonine, glutamic acid, tyrosine tryptophan alanine, and isoleucine in the stalks a lot. It was shown to be contained of essential amino acids like isoleucine, leucine, threonine, valine, methionine, lysine, phenylalanine, and tryptophan in the branches and steams more. As to the content of fatty acid in Salicornia herbacea, it found out that it contained the unsaturated fatty acid more than the saturated fatty acid. It took the content of eicosenoic acid(20:1) in the branches and stalks most. And then, it contained linoleic acid(18:2), pehtadecenoic acid(15:1), palmitic acid(16:0), and oleic acid(18:1), etc. a lot. As to the antioxidant activity in Salicornia herbacea using the DPPH radical, it was shown to be existed in the largest antioxidant activity when the concentration of methanolextract from Salicornia herbacea was 1 mM. There was higher antioxidant activity than 100 ppm BHT used as control plot when the concentration of methanol extract from the stalks was $100{\mu}M$. From the result of experiment above, Salicornia herbacea contained the essential amino acid a lot. It will be possible to be used as natural antioxidants because it has excellent antioxidant effect. Therefore, this researcher concludes that it will be available in using it as materials of functional foods.

• Korean Journal of Plant Resources
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• v.36 no.2
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• pp.107-121
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• 2023

This study analyzed the polyphenol, flavonoid contents, antioxidant activity, anti-aging activity and phenol component contents of Saccharina japonica (SJ), Costaria costata (CC) extracts with hot water, 95% methanol, 95% prethanol for investigating possible utilization of SJ and CC extracts. The result revealed that the SJ and CC methanol extracts showed the highest polyphenol and flavonoid contents, 4.63 mg TAN/g, and 4.19 mg QUE/g respectively. Also, the SJ and CC methanol extracts showed higher antioxidant activity than prethanol and hot water extracts, whereas the ABTS radical scavenging activities were the highest in prethanol extracts (IC₅₀ = 15.4, 10.3 ㎍/µL). In anti-aging activity for evaluating the anti-wrinkle activity and skin whitening activity, the CC methanol extracts had high collagenase inhibitory activity (88.3%), and the SJ prethanol extracts showed higher elastase inhibitory activity (19.0%) compared to other extracts. Then the tyrosinase inhibitory activity was significantly higher in the SJ and CC methanol extracts (41.8, 30.3%, respectively), whereas prethanol extracts were the lowest. To identify the phenol component contents of SJ and CC extracts, 4-hydroxybenzoic acid, naringenin, naringin and nicotinic acid were measured using LC-MS/MS. As a result, the phenol contents were the highest in SJ methanol extract (4-hydroxybenzoic acid), SJ and CC prethanol extract (naringin and naringenin) and CC prethanol extract (nicotinic acid). Lastly, the antioxidant activity of SJ and CC showed high correlations with polyphenol and flavonoid contents (R = -0.946~0.883). These results suggest that prethanol or methanol extracts of SJ and CC have higher antioxidant activities, anti-aging activity and the potential to be used as material for health functional food and cosmetics.

• Journal of Life Science
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• v.32 no.4
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• pp.325-330
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• 2022

While swimming is a very popular competitive sports activity, swimming injuries are unique due to the repetitive nature of the swimming stroke and demanding training programs that can result in upper limb overuse. Therefore, the primary objective of this review was to analyze swimmers' injury areas, injury types by stroke type, and swimming rehabilitation, as well as to discuss safety management for improving swimming performance. In this study, the injuries incurred in swimming events were discussed in the order of upper limb injuries (neck, shoulder, arm, and wrist), lower limb injuries (knee and ankle), and waist injuries. An analysis by stroke type found that shoulder injuries occurred most often with freestyle, backstroke, and butterfly strokes, followed by rotator cuff injury, impingement syndrome, and SLAP (superior labral tear from anterior to posterior) lesions. Knee injuries were associated with the breaststroke, whereas spinal cord injuries occurred with the breaststroke and butterfly stroke. Finally, back injuries were associated with the butterfly stroke. During the freestyle stroke, the shoulder undergoes repetitive overhead movement; hence, shoulder and musculoskeletal pain are the most common and well-documented complaints of swimmers. For safety management, coaches and instructors must ensure that athletes do sufficient warm-up and cool-down exercises to avoid injuries. In case of an injury, they should be familiar with first aid measures so that secondary damage can be prevented with its quick application. In addition, coaches and instructors need to be trained in injury prevention and treatment so that they can provide appropriate rehabilitation treatment for athletes. Although swimming-related injuries cannot be completely eliminated, to reduce them to a minimum, leaders need the knowledge to apply scientific and systematic training principles and methods individualized for each athlete.