• Journal of Positioning, Navigation, and Timing
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• v.12 no.3
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• pp.245-255
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• 2023

Time comparison techniques are necessary for generating and keeping Coordinated Universal Time (UTC) and distributing standard time clocks. Global Navigation Satellite System (GNSS) Common View, GNSS All-in-View, Two-Way Satellite Time and Frequency Transfer (TWSTFT), Very Long Baseline Interferometry (VLBI), optical fiber, and Network Time Protocol (NTP) based methods have been used for time comparison. In these methods, GNSS based time comparison techniques are widely used for time synchronization in critical national infrastructures and in common areas of application such as finance, military, and wireless communication. However, GNSS-based time comparison techniques are vulnerable to jamming or interference environments and it is difficult to respond to GNSS signal disconnection according to the international situation. In response, in this paper, Code-Division Multiple Access (CDMA) based All-to-All TWSTFT operation method is proposed. A software-based simulation platform also was designed for performance analysis in multi-TWSTFT signal environments. Furthermore, code and carrier measurement jitters were calculated in multi-signal environments using the designed simulation platform. By using the technique proposed in this paper, it is anticipated that the TWSTFT-based time comparison method will be used in various fields and satisfy high-performance requirements such as those of a GNSS master station and power plant network reference station.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.233-238
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• 2010

The geotechnical engineering research group in Korea Institute of Construction Technology(KICT), which was first started as a small sub-division of the civil research group in KICT, became an independent research cluster with nearly 90 researchers including 25 doctors(Ph.Ds). Our geotechnical engineering research group has developed to be the best research center related to geotechnical engineering in Korea in terms of number of budget of projects performed annually. As a reaction to the rapid changes of domestic and international issues regarding geotechnical practices, our group established long-term plans which will lead national research projects. For the successful and efficient research and technology development, the group is subdivided by several specialty-divisions. The divisions under the geotechnical engineering research group are tunnels and underground structures, slopes and embankments, geo-environment, foundations, soil reinforcements, and constructions in extremely cold regions. Our research scopes includes planning, site investigation, design, construction, maintenance and management. The geotechnical engineering research group is continuously and successfully examining and analyzing the most recent trends of technology and is predicting and focusing on the researches of newly-developing fields; therefore, the group has been a leading research group in geotechnical engineering nationally.

• Korean Journal of Medicinal Crop Science
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• v.21 no.4
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• pp.247-254
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• 2013

Collected germplasms of five representative dandelion species (Taraxacum ohwianum, T. platycarpum, T. platypecidum, T. officinale, and T. coreanum) were 104 lines from different habitates in Korea and China. Their genetic diversity was analyzed by genomic fingerprinting method using amplified fragment length polymorphism (AFLP). AFLP results of 6 primer combinations were revealed 1,176 total DNA fragments and 523 polymorphic bands with a 44.4% ratio of polymorphism. On the basis of similarity coefficient analysis by unweight pair group method with arithmetic averages (UPGMA), 104 dandelion germplasm lines were ranged from 0.64 to 0.99 and clustered distinct five group depending on the species. Furthermore, a principal coordinate analysis (PCA) by the application of multi-variate analysis indicated significantly greater differences among species than geographical origins.

• Reproductive and Developmental Biology
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• v.36 no.4
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• pp.249-254
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• 2012

This study aimed at investigating whether a porcine follicular fluid (pFF) supplementation positively affects the characteristics of donor cells and the developmental competence of porcine cloned embryos. Ear fibroblast cells (donor cell) from an Massachusetts General Hospital miniature pig were cultured in different culture methods: (1) Dulbecco's modified Eagle's medium (DMEM)+10% FBS (Control); (2) DMEM+0.5% FBS (SS); and (3) DMEM+10% FBS+10% pFF (pFF) for 72 h. In each conditioned medium, the concentrations of 4 amino acids (Thr, Glu, Pro, and Val) in the pFF group were significantly different from those in the control group (p<0.05 or p<0.01). The proliferation of the cells cultured in the SS group was significantly lower than that of the other treatment groups (p<0.01). The population of apoptotic and necrotic cells in the SS group was significantly higher than that of either the control or the pFF group (p<0.01). The number of embryos that cleaved (p<0.05) and developed into blastocysts (p<0.01) in the SS group was significantly lower than that of either the control or the pFF group. Compared to other groups, the blastocysts produced from the donor cells in the pFF group had higher total cells and lower apoptotic cells (p<0.05). It can be concluded that pFF supplementation in the donor cell culture medium positively affects cell death, cell cycle and quality of the cloned blastocyst.

• The Journal of Internal Korean Medicine
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• v.33 no.4
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• pp.418-428
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• 2012

Objectives : Ojeok-san, a traditional herbal formula, has been used for the treatment of cold illness and its related symptoms such as headache, nausea and indigestion. This study was performed to compare effects of water (OJSW) and 70% ethanol extracts (OJSE) of Ojeok-san on inflammation and its related diseases atopy, asthma and obesity in vitro. Methods : We performed HPLC to investigate contents of index components of OJSW and OJSE. We investigated the effects of OJSW and OJSE with an in vitro model, using 5 cell lines, specifically RAW 264. 7, HaCaT, MC/9, BEAS-2B and 3T3-L1. Results : HPLC analysis displayed that the contents of index components were higher in OJSE than OJSW. In lipopolysaccharide (LPS)-treated RAW 264.7 macrophages, OJSE significantly inhibited productions of interleukin (IL)-6, nitrite and prostaglandin $E_2$ ($PEG_2$). In TNF-${\alpha}$/IFN-${\gamma}$-treated HaCaT keratinocytes, OJSE significantly lowered levels of macrophage-derived chemokine (MDC) as well as regulated and normal T cell expressed and secreted (RANTES). OJSE also had a protective effect on inflammatory response by decreasing RANTES secretion in TNF-${\alpha}$-stimulated BEAS-2B cells. Conclusions : We conclude that OJSE could be more appropriate to enhance the biological activities against inflammation and its related diseases, and could be applied as a bioactive material for developing the potent anti-inflammatory agents.

• Korean Journal of Pharmacognosy
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• v.43 no.4
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• pp.328-337
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• 2012

In order to investigate anti-inflammatory, anti-allergic and anti-obesity activities of Samchulkunbi-tang (SCT; Shen zhu jian pi-tang) water and 70% ethanol (EtOH) extracts, in vitro inhibitory activities against nitric oxide (NO), prostaglandin $E_2$ $PGE_2$), interleukin (IL)-6 and tumor necrosis factor (TNF)-${\alpha}$ production in lipopolysaccharide-stimulated RAW 264.7 cells, and macrophage-derived chemokine (MDC/CCL22) and regulated on activation of normal T-cell-expressed and -secreted (RANTES/CCL5) production in TNF-${\alpha}$/interferon-${\gamma}$-stimulated HaCaT and BEAS-2B cells as well as glycerol-3-phosphate dehydrogenase (GPDH) activity and leptin production in 3T3-L1 cells were determined. A HPLC was used for quantification of the seven marker components (albiflorin, paeoniflorin, liquiritin, naringin, hesperidin, poncirin and glycyrrhizin) of SCT water and 70% EtOH extracts. SCT showed inhibitory effects against MDC and RANTES production in HaCaT cells, as well as RANTES production in BEAS-2B cells. In addition, SCT reduced not only NO, $PGE_2$, IL-6 and TNF-${\alpha}$ production in RAW 264.7 cells, but also GPDH activity and leptin production in 3T3-L1 cells. Furthermore, the biological activities and the contents of six compounds (except paeoniflorin) were higher in 70% EtOH extract than water extract. These results suggest that SCT has anti-inflammatory, anti-allergic and anti-obesity activities. These efficacies of 70% EtOH extract are relatively higher than that of water extract.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.6
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• pp.908-914
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• 2012

To investigate the difference and change of ingredient and efficacy of Galgeun-tang (GGT) according to extraction solvent, water and 70% EtOH, the quantities of index components and the several in vitro activities of two kinds of GGT extract were compared. The contents of extracts were analyzed with HPLC. The biological activities such as anti-inflammatory and anti-obesity effects were measured through cell line-based in vitro assay. The cytotoxicity was measured by CCK-8 assay in RAW 264.7 cell, BEAS-2B cell, HaCaT cell and 3T3-L1 cell. We compared effects of two kinds of extract by measuring NO, PGE2, IL-6 and TNF-${\alpha}$ in RAW264.7 cell, RANTES in BEAS-2B cell, MDC and RANTES in HaCaT cell and GPDH activity and leptin level in differentiated 3T3-L1. 70% EtOH extract of GGT contained more compositions than water extract. The inhibitory effect of water extract of GGT on NO in RAW 264.7 cell and GPDH activity in 3T3-L1 was stronger than that of 70% EtOH. 70% EtOH has a stronger inhibitory effect on PGE2 in RAW264.7 cell, RANTES in BEAS-2B cell, MDC, RANTES in HaCaT cell, leptin in 3T3-L1 cell than water extraction. These results suggest that the ingredient and efficacy from 70% EtOH extract of GGT are more effective than water extract.

• The Korea Journal of Herbology
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• v.27 no.6
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• pp.115-122
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• 2012

Objectives : This study evaluated activities and ingredient contents concerning extracts according to extraction solvents of Insampaedok-san (IS, Renshen bai du-san). Methods : The herbal constituents of IS were extracted with water and 70% ethanol at $100^{\circ}C$ for 2 hr. Using the HPLC system, the six ingredient contents of different solvent extracts of IS were analyzed. The nitric oxide (NO), prostaglandin $E_2$ ($PGE_2$) production and proinflammatory cytokines were measured in RAW264.7 cells stimulated with lipopolysaccharide (LPS). The macrophage-derived chemokine (MDC/CCL22) and regulated on activation normal T-cell expression and secreted (RANTES/CCL5) production were measured in HaCaT and BEAS-2B cells stimulated tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and interferon-${\gamma}$ (IFN-${\gamma}$). The activities of glycerol-3-phosphate dehydrogenase (GPDH) and leptin level were measured in 3T3-L1 cells. Results : The calibration curves showed good linearity ($r^2$=1.0000) for different concentration ranges. The contents of liquiritin, naringin, hesperidin, neohesperirin and glycyrrizin in 70% ethanol extracts of IS were relatively higher than that of water extract, however the content of ferulic acid in 70% ethanol and water extract of IS were similar. The extraction solvents of water and 70% ethanol were evaluated inhibitory effect on the production of NO, $PGE_2$, TNF-${\alpha}$ and IL-6 in RAW 264.7 cells. Their extractions were inhibitory effect on production of MDC/CCL22 and RANTES/CCL5 in HaCaT cell and BEAS-2B cell, respectively. In addition, evaluated reduced on GPDH activity and leptin level in 3T3-L1 preadipocyte cell. Conclusions : Our results suggest that IS extracts were inhibitory effects of disease such as inflammation, allergies and obesity.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1099-1102
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• 2007

• Korean Journal of Metals and Materials
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• v.46 no.1
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• pp.6-12
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• 2008

Peptides with specific sequences against $LaPO_4$ and $TiO_2$ nanoparticles were discovered through peptide phage display technique as an application to biomolecular recognition of inorganic materials. Sequencing results showed that a motif consisting of serine and proline was commonly expressed in specific sequences. It was postulated that serine directly bound to nanoparticles using its terminal hydroxyl (OH) group. In this sense, oxygen atom seemed to work as a ligand to metal ions and hydrogen atom as a H-bond donor, was thought to bind to the oxygen atoms or the hydroxyl groups on particle surface. Also, it was expected that proline assists serine to make an ideal van der Waals contact between serine and nanoparticles, which optimizes the binding of peptide onto surface.