• Food Engineering Progress
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• v.21 no.1
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• pp.57-63
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• 2017

This study investigated the effects of 27.12 MHz radio frequency (RF) heating on heat transfer phenomena during the thawing process of frozen food. To determine the velocity of the RF thawing machine, samples were frozen at $-80^{\circ}C$ and subjected to different power treatments. The phase change times (-5 to $0^{\circ}C$) of frozen radish were 30, 26, 13, and 8 min; those of pork sirloin were 38, 25, 11, and 5 min; those of rump were 23, 17, 11, and 6 min; those of chicken breast were 42, 29, 13, and 9 min; and those of tuna were 25, 23, 10, and 5 min at 50, 100, 200, and 400 W, respectively. The heating limit temperatures of the radish, pork sirloin, rump, chicken breast, and tuna samples were 19.5, 9.2, 21.8, 8.8, and $16.8^{\circ}C$ at 50 W; 23.5, 15.5, 27.3, 12.3, and $19^{\circ}C$ at 100 W; 42, 26.9, 45.7, 22.1, and $39.4^{\circ}C$ at 200 W; and 48.5, 54.7, 63.6, 57.3, and $44.9^{\circ}C$ at 400 W. These results suggest that high-power RF improves thawing velocity and heating limit temperatures, and that an improvement on the operation of the RF thawing machine, according to food temperatures, is needed.

• Korean Journal of Remote Sensing
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• v.34 no.6_4
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• pp.1503-1517
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• 2018

Mt. Baekdu is a stratovolcano located at the border between China and North Korea and is known to have formed through its differentiation stage after the Oligocene epoch in the Cenozoic era. There has been a growing interest in the magma re-activity of Mt. Baekdu volcano since 2010. Several research projects have been conducted by government such as Korea Meteorological Administration and Korea Institute of Geoscience and Mineral Resources. Because, however, the Mt. Baekdu volcano is located far from South Korea, it is quite difficult to collect in-situ observations by terrestrial equipment. Remote sensing is a science to analyze and interpret information without direct physical contact with a target object. Various types of platform such as automobile, unmanned aerial vehicle, aircraft and satellite can be used for carrying a payload. In the past several decades, numerous volcanic studies have been conducted by remotely sensed observations using wide spectrum of wavelength channels in electromagnetic waves. In particular, radar remote sensing has been widely used for volcano monitoring in that microwave channel can gather surface's information without less limitation like day and night or weather condition. Radar interferometric technique which utilized phase information of radar signal enables to estimate surface displacement such as volcano, earthquake, ground subsidence or glacial movement, etc. In 2018, long-term research project for collaborative observation for Mt. Baekdu volcano between Korea and China were selected by Korea government. A volcanic specialized research center has been established by the selected project. The purpose of this paper is to introduce about remote sensing techniques for volcano monitoring and to review selected studies with remote sensing techniques to monitor Mt. Baekdu volcano. The acquisition status of the archived observations of six synthetic aperture radar satellites which are in orbit now was investigated for application of radar interferometry to monitor Mt. Baekdu volcano. We will conduct a time-series analysis using collected synthetic aperture radar images.

• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.498-506
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• 2019

This study is based on a coating method that provides utilization value as a micronised powder for cosmetic raw materials using natural minerals buried in Bonghwa, Gyeongsangbuk-do in Korea. The mineral powder name is called Buseok, and chemical name is pumice powder. The results of a study on the efficacy of cosmetics are reported by the development of particulate powder to assess the performance of this powder. First of all, in order to coat the surface of this powder with oil, aluminum hydroxide was coated on the particulate surface and then coated with alkylsilan. In addition, it was coated with vegetable oil to prevent condensation of the powder and increase the dispersion in the oil phase. First; the particle size of pumice powder was from 10 to 50mm having porous holes on the surface of the particles. Second; The components of this powder contained $SiO_2$, $Al_2O_3$, $Fe_2O_3$, MgO, CaO, $K_2O_2$, $Na_2O$, $TiO_2$, $TiO_2$, MnO, $Cr_2O_3$, $V_2O_5$. Third: The particles of this powder have a planetary structure and are reddish-brown with porosity through SEM and TEM analysis. Fourth; the far-infrared radiation rate of this parabolic powder was $0.924{\mu}m$, and the radiative energy was $3.72{\times}102W/m^2$ and ${\mu}m$. In addition, the anion emission is 128 ION/cc, which shows that the coating remains unchanged. Based on these results, it is expected to be widely applied to basic cosmetics such as BB cream, cushion foundation, powderfect, and other color-coordinated cosmetics, sunblock cream, wash-off massage pack as an application of cosmetics. (Small and Medium Business Administration: S2601385)

• Economic and Environmental Geology
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• v.52 no.3
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• pp.223-230
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• 2019

The calcination of oyster shells have been studied as the possible substitute for the limestone used as an absorbent of $SO_2$ gas. However, since pure shells can not be used in calcination process, some impurities are contained and the changes in the characteristics of the calcination products are expected. In this study, the surface characteristics of the calcination products are investigated by mineralogical analysis according to the contents of NaCl, which can be derived from sea water, and sediments on the surface of the shell as impurities. The marine sediments on the shells were mainly composed of quartz, albite, calcite, small amounts of amphibole and clay minerals such as ilite, chlorite and smectite. After calcination of oyster shells mixed with 0.2-4.0 wt% sediments at $900^{\circ}C$ for 2 hours, regardless of the dehydration, dehydroxylation, and phase change of these minerals at the lower temperature than this experiment, no noticeable changes were observed on the specific surface area of the calcined product. However, when mixed with 0.1 to 2.0 wt% NaCl, the specific surface area generally increases as compared with the shell sample before calcination. The specific surface area increases with increasing amount of salt, and then decreases again. This is closely related to the changes of surface morphology. As the amount of NaCl increases, the morphology of the surface is similar to that of gel. It changes into a slightly angular, smaller particle and again looks like gel with increasing amount of NaCl. Our results show that NaCl affects morphological changes probably caused by melting of some oyster shells, but may have different effects on the specific surface area of calcination product depending on the NaCl contents.

• Korean Journal of Heritage: History & Science
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• v.39
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• pp.219-242
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• 2006

Quantitative analysis and provenance interpretation of the raw materials for the jade (amazonite) excavated from the Asan Sijeonri site were studied. Geology of the Sijeonri site composed mainly of Precambrian metasedimentary rocks and the alluvium ranges extensively. In the site, amazonite jade was excavated in the Bronze Age No. 4 circular-shaped resident site. The jade has a comma-shaped and shows light green color with so much cracks. The jade is silicate mineral of columnar habits that is shown white streak, and has fine cleavages with vitreous luster. As the analytical results, this jade was identified as a feldspar-group mineral gemologically called amazonite that is mineralogically microcline formed to intergrowth of albite and orthoclase. Internal textures of the amazonite present Na-end member of albite coexisting with K-end member of orthoclase that are replaced each other along the cleavages and twin planes with several ${\mu}m$ scales. Therefore, the amazonite is one mineral phase combined with albite and orthoclase by substitution of $Na_2O$ and $K_2O$, respectively. The Danyang are is an unique producing site of amazonite in South Korea, and Gongju Janggimyeon was known as microcline provenance to the utmost area from the Sijeonri site. In the marginal area of southern coast in Korean Peninsula, Bronze Age amazonite has been excavated in several sites, where original provenance of the raw amazonite is not identified. The Sijeonri site does not show any facilities of producing and processing traces for amazonite jade. Also, only one jade was collected in the Sijeonri site. Therefore, there is not possibility that the provenance of raw jade is the Sijeonri area. To explain original provenance of the amazonite jade, migration path, manufacturing process and archaeological interpretation are required.

• Korean Journal of Heritage: History & Science
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• v.38
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• pp.305-327
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• 2005

Although the stone pagoda in Mireuk Temple site, Iksan, Cholla Province has been collapsed long time ago, few historical record has clearly explained the reason why the pagoda was collapsed and when. The west side of the pagoda have been destroyed from top to the sixth floor and the broken or damaged stone materials have been piled up in disorder. the lower part in the west was reinforced and enclosed by a stone embankment levelled to the height of the first storey of the pagoda. With no record informing the historical fact when it was made and by whom, it is only presumed that the embankment may have been built long time ago in order to prevent remains from further destruction. In the second chapter of the study, it has been tried to restore a reasonable historical background of the pagoda based on records or comments found in literatures such as traditional poetry and essays in chronological order. The collapsed slope in the west side, just above the embankment surrounding the lower part of the pagoda, was concreted in 1915 during the Japanese colonial period. Then in 1998, the Jeollabukdo has examined the structural safety of the pagoda. The Cultural Properties Committee has decided have the concrete layer removed and moreover to take apart the whole pagoda. It is also included that the disassembled stone materials should be given proper conservation treatments before being put into the place where they were in the reassembling process. The front view of the collapsed phase of the pagoda was revealed when the concrete-covered layer was removed. A hypothesis was built that there may be as many different appearances of collapsed pagoda depending on natural causes such as earthquake, sunken foundation, flood and typhoon. In chapter three, characteristic features were classified by examining various images of pagodas destroyed by different natural reasons mentioned in historical records. The chapter four dealt with comparison and analysis on the conditions shown in the stone pagoda in Mireuk Temple site and other examples studied in advance. The result of the study revealed that though having been made higher than the ground surface, the podium or the base of the pagoda actually has been eroded by rain and water. The erosion is supposed not only to have been proceeded for a long time without break but also to have caused the first storey body stone in the west inclined to outward. It has come to a conclusion that the pagoda may have been lead to collapse when the first storey body stone, supporting the whole weight from the upper storeys, became out of upright position and lost its balance. However, no such distinctive features of structural changes shown in pagodas collapsed by natural causes like earthquake, typhoon or sunken basement, have been found in the stone pagoda in Mireuk Temple site.

• Journal of Apiculture
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• v.32 no.3
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• pp.139-146
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• 2017

Floral scent emitted from many plants is the critical factors for pollinator attraction and defense for adaptation in environments. The fragrance components of flowers are different in composition by geographical origins, climate factors and the development stages of flowers. In the present study, we investigated the volatile-floral compounds in flowers of Robinia pseudoacacia L. and defined the chemical contribution for flowering periods. The volatile compounds analysis was performed by gas chromatography with mass selective detector after solid phase microextraction (SPME). We reported different compositional features of fragrance compounds according to flowering periods. The abundant compounds identified in stage 1 were ${\alpha}$-pinene (66.80%) and ${\beta}$-pinene (26.53%). Those of the stage 2 were (Z)-${\beta}$-ocimene (37.57%), ${\alpha}$-pinene (15.16%), benzaldehyde (16.63%), linalool (12.13%). The volatiles of stage 3 comprised an abundance of (Z)-${\beta}$-ocimene (64.94%), ${\alpha}$-pinene (9.84%), linalool (8.92%), benzaldehyde (1.71%). Leaf volatiles were distinct from those in the reproductive plant parts by their high relative amount of (E)-${\beta}$-ocimene (23.50%) and (Z)-3-Hexenyl acetate (27.87%). Differences in flower scents of the different stages and leaves are discussed in light of biochemical constraints on volatile chemical synthesis and of the role of flower scent in evolutionary ecology of R. pseudoacacia.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.3-16
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• 2008

A Wireless Sensor Network (WSN for short) is a wireless network consisting of distributed small devices which are called sensor nodes or motes. Recently, there has been an extensive research on WSN and also on its security. For secure storage and secure transmission of the sensed information, sensor nodes should be equipped with cryptographic algorithms. Moreover, these algorithms should be efficiently implemented since sensor nodes are highly resource-constrained devices. There are already some existing algorithms applicable to sensor nodes, including public key ciphers such as TinyECC and standard block ciphers such as AES. Stream ciphers, however, are still to be analyzed, since they were only recently standardized in the eSTREAM project. In this paper, we implement over the MicaZ platform nine software-based stream ciphers out of the ten in the second and final phases of the eSTREAM project, and we evaluate their performance. Especially, we apply several optimization techniques to six ciphers including SOSEMANUK, Salsa20 and Rabbit, which have survived after the final phase of the eSTREAM project. We also present the implementation results of hardware-oriented stream ciphers and AES-CFB fur reference. According to our experiment, the encryption speeds of these software-based stream ciphers are in the range of 31-406Kbps, thus most of these ciphers are fairly acceptable fur sensor nodes. In particular, the survivors, SOSEMANUK, Salsa20 and Rabbit, show the throughputs of 406Kbps, 176Kbps and 121Kbps using 70KB, 14KB and 22KB of ROM and 2811B, 799B and 755B of RAM, respectively. From the viewpoint of encryption speed, the performances of these ciphers are much better than that of the software-based AES, which shows the speed of 106Kbps.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.3
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• pp.11-28
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• 2021

Due to its size and complex characteristics, it is not often to newly create a large park within an existing urban area. Also, there has been a lack of research on the planting design methodologies for a large park. This study aims to elucidate how ecological ideas can be applied to planting practice from a designer's perspective, and eventually suggest a planting design framework in the actual case, the Central Park in the City of Gwangju. This framework consists of spatial structure of planting area in order to connect and unite the separated green patches, to adapt to the changes of existing vegetation patterns, to maintain the visual continuity of landscape, and to organize the whole open space system. The framework can be provided for the spatial planning and planting design phase in which the landscape designer flexibly uses it with the design intentions as well as with an understanding of the physical, social, and aesthetic characteristics of the site. The significance of this approach is, first that it can maintain ecological and visual consistency of the both existing and introduced landscapes as a whole in spite of its intrinsic complexity and largeness, and second that it can help efficiently respond to the unexpected changes in the landscape. In the case study, comprehensive site analysis is conducted before developing the framework. In particular, wetlands and grasslands have been identified as potential wildlife habitat which critically determines the vegetation patterns of the green area. Accordingly, the lists of plant communities are presented along with the planting scheme for their shape, layout, and relations. The model of the plant community is developed responding to the structure of surrounding natural landscape. However, it is not designed to evolve to a specific plant community, but is rather a conceptual model of ecological potentials. Therefore, the application of the model has great flexibility by using other plant communities as an alternative as long as the characteristics of the communities are appropriate to the physical conditions. Even though this research provides valuable implications for landscape planning and design in the similar circumstances, there are several limitations to be overcome in the further research. First, there needs to be more sufficient field surveys on the wildlife habitats, which would help generate a more concrete planting model. Second, a landscape management plan should be included considering the condition of existing forest, in particular the afforested landscapes. Last, there is a lack of quantitative data for the models of some plant communities.

• Korean Journal of Plant Resources
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• v.35 no.5
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• pp.565-573
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• 2022

Gingival inflammation is one of the main causes that can be related to various periodontal diseases. Human gingival fibroblast (HGF) is the major constituent in periodontal connective tissue and secretes various inflammatory mediators, such as nitric oxide (NO) and prostaglandin E₂ (PGE₂), upon lipopolysaccharide stimulation. This study is aimed at investigating the anti-inflammatory and antioxidative activities of Lotus Root extract (LRE) in Porphyromonas gingivalis derived lipopolysaccharide (LPS-PG)-stimulated HGF-1 cells. The concentration of NO and PGE₂, as well as their responsible enzymes, inducible NO synthase (iNOS), and cyclooxygenase-2 (COX-2), was analyzed by Griess reaction, ELISA, and western blot analysis. LPS-PG sharply elevated the production and protein expression of inflammatory mediators, which were significantly attenuated by LRE treatment in a dose-dependent manner. LRE treatment also suppressed activation of Toll-like receptor 4 (TLR4)/myeloid differentiation primary response gene 88 (MyD88) and nuclear factor-κB (NF-κB) in LPS-PG-stimulated HGF-1 cells. In addition, one of phase II enzyme, NAD(P)H quinone dehydrogenase (NQO)-1, and its transcription factor, Nuclear factor erythroid 2-related factor 2 (Nrf2), were significantly induced by LRE treatment. Consequently, these results suggest that LRE ameliorates LPS-PG-induced inflammatory responses by attenuating TLR4/MyD88-mediated NF-κB, and activating NQO-1/Nrf2 antioxidant response element signaling pathways in HGF-1 cells.