• Journal of the Korea Institute of Information and Communication Engineering
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• v.1 no.2
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• pp.209-220
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• 1997

DBS offers actual services to mass-media and communication system of very broad region in information society. Especially, the DBS is the only system to access TV broadcasting service on a sailing ship. But the ship's DBS receiver is required a complex antenna tracking system because ships are under complex moving such as pitch, roll, and yaw etc. This study is motivated to develop a tracking antenna system to receive the koreasat on small silo ship. Therefore, this system is researched to small size, light weight, simple operation, and low cost of the product. The mount structure have been a compact size and easy operation to the Az/El 2-axis type which is operated by step motor. And it is very useful on a ship in the around sea of korean peninsula. The antenna has a plate type of micro-strip array, and is a domestic production. The vibration sensor is selected to gyro sensor of ultra-sonic rate type for ship's moving control. Tracking method is used the step-tracking algorithm, and the ship's moving compensation is adapted to the closed loop control method by ship's moving detection of gyro sensor. Tracking test is operated by the ship's moving simulator, we examined the actual receiving state on sailing shipboard in the near sea of korean peninsular.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.333-335
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• 2006

Position of surface objects can be fixed in many ways. The most popular radionavigational systems, including satellite systems, make possible obtaining nearly continuous and very precise ship's position. However, under the water application of radionavigational systems is impossible. Underwater navigation requires other tools and solutions then these encountered in surface and air navigation. In underwater environment vehicles and submarines, operate that have to possess alternative navigational systems. Underwater vehicles, in order to perform their tasks require accurate information about their own, current position. At present, they are equipped with inertial navigational systems (INS). Accuracy of INS is very high but in relatively short periods. Position error is directly proportional to time of working of the system. The basic feature of INS is its autonomy and passivity. This characteristic mainly decides that INS is broadly used on submarines and other underwater vehicles. However, due to previously mentioned shortcoming i.e. gradually increasing position error, periodical calibration of the system is necessary. The simplest calibration method is surface or nearly surface application of GPS system. Another solution, which does not require interruption of performed task and emergence on the surface, is application of comparative navigation technique. Information about surrounding environment of the ship, obtained e.g. by means sonic depth finder or board sonar, and comparing it with accessible pattern can be used in order to fix ship's position. The article presents a structure and a description of working of underwater vehicle navigation system simulator. The simulator works on the basis of comparative navigation methods which exploit in turn digital images of echograms and sonograms. The additional option of the simulator is ability to robust estimation of measurements. One can do it in order to increase accuracy of position fixed with comparative navigation methods application. The simulator can be a basis to build future underwater navigation system.

• Microbiology and Biotechnology Letters
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• v.16 no.4
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• pp.293-296
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• 1988

Stability of spheroplasts prepared from Saccharomyces cerevisiae D-71, a thermophilic strain and Zygosaccharomyces rouxii SR-S, an osmotolerant strain were studied. Stability of spheroplast from Saccharomyces cerevisiae D-71 was highest in 0.8M KCI and 1.0M sorbitol ; that from Zygosaccharomyces rouxii SR-S was highest in 0.4M KCI and mannitol and that from both strains was less than 10% for sonic oscillation at 20Kc for 60 sec. In centrifugation at 10000 x g for 10 min., stability of spheroplast from Saccharomyces cerevisiae D-71 was 93% and that from Zygosaccharomyces rouxii SR-S was 84%. Breakage of spheroplast from Saccharomyces cerevisiae D-71 was 99% and that from Zygosaccharomyces rouxii SR-S was 55% for UV irradiation with 15W UV lamp at a distance of 20 cm for 60 min.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.15-21
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• 2013

We previously observed that Bacillus subtilis spores from sspE mutants presented a lower germination capacity in media containing high salt concentrations (0.9M NaCl). This deficiency was attributed to the absence of SASP-E (gamma-type small-acid-soluble protein), rich in osmocompatible amino acids released by degradation. Herein we observed that, in addition, this mutant spore presented a reduced capacity to use L-alanine as germinant (L-ala pathway), required longer times to germinate in calcium dipicolinate ($Ca^{2+}$-DPA), but germinated well in asparagine, glucose, fructose, and potassium chloride (AGFK pathway). Moreover, mild sonic treatment of mutant spores partially recovered their germination capacity in L-ala. Spore qualities were also altered, since sporulating colonies from the sspE mutant showed a pale brownish color, a higher adherence to agar plates, and lower autofluorescence, properties related to their spore coat content. Furthermore, biochemical analysis showed a reduced partition in hexadecane and a higher content of $Ca^{2+}$-DPA when compared with its isogenic wild-type control. Coat protein preparations showed a different electrophoretic pattern, in particular when detected with antibodies against CotG and CotE. The complementation with a wild-type sspE gene in a plasmid allowed for recovering the wild-type coat phenotype. This is the first report of a direct involvement of SASP-E in the spore coat assembly during the differentiation program of sporulation.

• Restorative Dentistry and Endodontics
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• v.40 no.2
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• pp.128-135
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• 2015

Objectives: This study evaluated the effects of the resin thickness on the microhardness and optical properties of bulk-fill resin composites. Materials and Methods: Four bulk-fill (Venus Bulk Fill, Heraeus Kulzer; SDR, Dentsply Caulk; Tetric N-Ceram Bulk Fill, Ivoclar vivadent; SonicFill, Kerr) and two regular resin composites (Charisma flow, Heraeus Kulzer; Tetric N-Ceram, Ivoclar vivadent) were used. Sixty acrylic cylindrical molds were prepared for each thickness (2, 3 and 4 mm). The molds were divided into six groups for resin composites. The microhardness was measured on the top and bottom surfaces, and the colors were measured using Commission Internationale d'Eclairage (CIE) $L^*a^*b^*$ system. Color differences according to the thickness and translucency parameters and the correlations between the microhardness and translucency parameter were analyzed. The microhardness and color differences were analyzed by ANOVA and Scheffe's post hoc test, and a student t-test, respectively. The level of significance was set to ${\alpha}=0.05$. Results: The microhardness decreased with increasing resin thickness. The bulk-fill resin composites showed a bottom/top hardness ratio of almost 80% or more in 4 mm thick specimens. The highest translucency parameter was observed in Venus Bulk Fill. All resin composites used in this study except for Venus Bulk Fill showed linear correlations between the microhardness and translucency parameter according to the thickness. Conclusions: Within the limitations of this study, the bulk-fill resin composites used in this study can be placed and cured properly in the 4 mm bulk.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.139-145
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• 2010

An integrity testing for stone columns was attempted using crosshole S-wave logging. The method is conceptionally quite similar to the crosshole sonic logging (CSL) for drilled piers. The critical difference in the logging is the use of S-wave rather than P-wave, which is used in CSL, because swave is the only wave sensing the stiffness of slower unbounded materials than water. An electro-mechanical source, which can generate reversed Swave signals, was utilized in the logging. The stone column was delineated using the S-wave travel times across the stone column, the S-wave velocity profile of the crushed stone($V_{cs}$-profile) and that of surrounding soil($V_s$-profile). In the calculation of $V_{cs}$-profile of the crushed stone, its friction angle and Ko (coefficient of lateral earth pressure at rest) are recommended to be used. The calculation of the column diameter is not much affected by the values of friction angle and Ko.

• Development and Reproduction
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• v.25 no.4
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• pp.279-291
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• 2021

Hair loss is one of the most common chronic diseases, with a detrimental effect on a patient's psychosocial life. Hair loss results from damage to the hair follicle (HF) and/or hair regeneration cycle. Various damaging factors, such as hereditary, inflammation, and aging, impair hair regeneration by inhibiting the activation of hair follicle stem cells (HFSCs) and dermal papilla cells (DPCs). Formyl peptide receptor 2 (FPR2) regulates the inflammatory response and the activity of various types of stem cells, and has recently been reported to have a protective effect on hair loss. Given that stem cell activity is the driving force for hair regeneration, we hypothesized that FPR2 influences hair regeneration by mediating HFSC activity. To prove this hypothesis, we investigated the role of FPR2 in hair regeneration using Fpr2 knockout (KO) mice. Fpr2 KO mice were found to have excessive hair loss and abnormal HF structures and skin layer construction compared to wild-type (WT) mice. The levels of Sonic hedgehog (Shh) and β-catenin, which promote HF regeneration, were significantly decreased, and the expression of bone morphogenetic protein (Bmp)2/4, an inhibitor of the anagen phase, was significantly increased in Fpr2 KO mice compared to WT mice. The proliferation of HFSCs and DPCs was significantly lower in Fpr2 KO mice than in WT mice. These findings demonstrate that FPR2 impacts signaling molecules that regulate HF regeneration, and is involved in the proliferation of HFSCs and DPCs, exerting a protective effect on hair loss.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.470-476
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• 2019

The braking force for a train is generally provided by compressed air. The pressure valve system that is used to apply appropriate braking forces to trains has a complex flow circuit. It is possible to make a channel shape that can increase the flow efficiency by 3D printing. There are restrictions on the flow shape design when using general machining. Therefore, in this study, the compressed air flow was analyzed in a pressure valve system by comparing flow paths made with conventional manufacturing methods and 3D printing. An analysis was done to examine the curvature magnitude of the flow path, the diameter of the flow path, the magnitude of the inlet and reservoir pressure, and the initial temperature of the compressed air when the flow direction changes. The minimization of pressure loss and the uniformity of the flow characteristics influenced the braking efficiency. The curvilinear flow path made through 3D printing was advantageous for improving the braking efficiency compared to the rectangular shape manufactured by general machining.

• Molecules and Cells
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• v.42 no.9
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• pp.661-671
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• 2019

Adipose tissue-derived mesenchymal stem cells (ADSCs) are promising for regenerating degenerated intervertebral discs (IVDs), but the low efficiency of nucleus pulposus (NP)-specific differentiation limits their clinical applications. The Sonic hedgehog (Shh) signaling pathway is important in NP-specific differentiation of ADSCs, and Smoothened Agonist (SAG) is a highly specific and effective agonist of Shh signaling. In this study, we proposed a new differentiation strategy with the use of the small molecule SAG. The NP-specific differentiation and extracellular matrix (ECM) synthesis of ADSCs were measured in vitro, and the regenerative effects of SAG pretreated ADSCs in degenerated IVDs were verified in vivo. The results showed that the combination of SAG and transforming growth factor-${\beta}3$ ($TGF-{\beta}3$) is able to increase the ECM synthesis of ADSCs. In addition, the gene and protein expression levels of NP-specific markers were increased by treatment with SAG and $TGF-{\beta}3$. Furthermore, SAG pretreated ADSCs can also improve the disc height, water content, ECM content, and structure of degenerated IVDs in vivo. Our new differentiation scheme has high efficiency in inducing NP-specific differentiation of ADSCs and is promising for stem cell-based treatment of degenerated IVDs.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.3
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• pp.341-349
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• 2019

Objective: Internal organs indirectly affect economic performance and well-being of animals. Study of internal organs during later layer period will allow full utilization of layer hens. Hence, we conducted a genome-wide association study (GWAS) to identify potential quantitative trait loci or genes that potentially contribute to internal organ weight. Methods: A total of 1,512 chickens originating from White Leghorn and Dongxiang Blue-Shelled chickens were genotyped using high-density Affymetrix 600 K single nucleotide polymorphism (SNP) array. We conducted a GWAS, linkage disequilibrium analysis, and heritability estimated based on SNP information by using GEMMA, Haploview and GCTA software. Results: Our results displayed that internal organ weights show moderate to high (0.283 to 0.640) heritability. Variance partitioned across chromosomes and chromosome lengths had a linear relationship for liver weight and gizzard weight ($R^2=0.493$, 0.753). A total of 23 highly significant SNPs that associated with all internal organ weights were mainly located on Gallus gallus autosome (GGA) 1 and GGA4. Six SNPs on GGA2 affected heart weight. After the final analysis, five top SNPs were in or near genes 5-Hydroxytryptamine receptor 2A, general transcription factor IIF polypeptide 2, WD repeat and FYVE domain containing 2, non-SMC condensin I complex subunit G, and sonic hedgehog, which were considered as candidate genes having a pervasive role in internal organ weights. Conclusion: Our findings provide an understanding of the underlying genetic architecture of internal organs and are beneficial in the selection of chickens.