• Korean Journal of Mathematics
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• v.25 no.1
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• pp.45-60
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• 2017

This paper focuses on estimation of an non-integral quadratic function (NIQF) and integral quadratic function (IQF) of a random signal in dynamic system described by a linear stochastic differential equation. The quadratic form of an unobservable signal indicates useful information of a signal for control. The optimal (in mean square sense) and suboptimal estimates of NIQF and IQF represent a function of the Kalman estimate and its error covariance. The proposed estimation algorithms have a closed-form estimation procedure. The obtained estimates are studied in detail, including derivation of the exact formulas and differential equations for mean square errors. The results we demonstrate on practical example of a power of signal, and comparison analysis between optimal and suboptimal estimators is presented.

• Journal of Korea Multimedia Society
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• v.20 no.4
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• pp.629-639
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• 2017

Interpolation based information hiding methods are widely used to get information security. Conventional interpolation methods use the neighboring pixel value and simple calculation like average to embed secret bit stream into the image. But these information hiding methods are not appropriate to color images like military images because the characteristics of military images are not considered and these methods are restricted in grayscale images. In this paper, the new information hiding method based on interpolation using RGB pixel values of color image is proposed and the effectiveness is analyzed through experiments.

• Journal of the korean society of oceanography
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• v.35 no.4
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• pp.192-199
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• 2000

Standard CTD data processing recommended by Sea-Bird Electronics produced thermal-lag corrections larger than 0.1 psu for the data taken during the CREAMS expeditions in the northern part of the East/Japan Sea where a vertical temperature gradient frequently exceeds 1.0$^{\circ}$C/m in the upper 100 m near the sea surface. As the standard processing is based upon a recursive filter which was introduced by Lueck and Pickle (1990), coefficients of the recursive filter have been newly derived for the CREAMS data by minimizing the difference between salinities of downcast and upcast in temperature-salinity domain. The new coefficients are validated by comparison with salinities measured by a salinometer, AUTOSAL 8400B. An accurate correction for the thermal-lag is critical in identifying water masses at intermediate depth in the East/japan Sea.

• Korean Journal of Remote Sensing
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• v.30 no.1
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• pp.75-81
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• 2014

Until recently, photogrammetric applications for processing the satellite images and remotely sensed data have been used in different structure of functions and interfaces for sensor modeling by each developer. Thus, a standardized utilization procedure was necessary to solve the problems, such as expandability, cost, inefficiency of sources which were resulted from different approaches. Therefore, National Geospatial Intelligence Agency (NGA) provided unified interfaces by developing Community Sensor Model (CSM) to sensor models in same way. In this study, we suggested the method of design and analyzed main functions needed modeling for the frame sensor using CSM Application Program Interface (API) provided by NGA. We also applied the designed structure to the modeling. The implemented CSM was verified by groundToImage and imageToGround. In the future, the active R&D is expected with using CSM due to the cost saving effect of software development and remarkable expandability of sensor.

• Korean Journal of Plant Resources
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• v.23 no.2
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• pp.172-178
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• 2010

This study was carried out to investigate abiotic and biotic environmental factors affecting homoharringtonine (HHT) contents of Cephalotaxus koreana, whereby, to provide basic information of high value-added industry production of HHT as a promising anti-cancer agent. For correlation between abiotic environmental factors (soil moisture, soil pH, habitat density and temperature) and HHT contents, the contents were highly correlated with soil moisture (0.77) and soil pH (-0.68). For multiple regression analysis of relationship between abiotic environmental factors (soil moisture and soil pH) and HHT contents, soil moisture appeared to be strongly affecting the contents relatively due to being significant at only its regression coefficient ($26.48^{***}$). For the effect of biotic environmental factors (damage index) affecting HHT contents, the contents was quadratic with equation of $H=278.23+1242D-398.87D^2$, also, damage index had strong effect on the contents. Finally, for the result of the most influencing an environmental factor on HHT contents, both damage index and soil moisture were suitable in second polynomial regression, also, damage index ($R^2=0.73^{***}$) was turned out to be more influencing factor than soil moisture ($R^2=0.67^{**}$) on HHT contents relatively. Therefore, we predict that HHT contents in the trees of Cephalotaxus koreana is produced as a chemical defense mechanism triggered by a stress-related damage of fungi or insects.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.5
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• pp.593-600
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• 2014

In this paper, Radar cross section (RCS) calculations of advanced naval vessels model with RCS reduction methods are simulated and RCS results are discussed. Especially, this paper are mainly focusing on the facts influencing on RCS, the ways minimizing RCS and material characteristics of RCS changing-rate. RCS analysis results are given for a DDG-1000 type advanced naval vessels, which show that as the elevation angle increased 10 degree, the mean RCS value increased 23.91 dBsm. Also, as the superstructure angle increased 6 degree, the mean RCS value reduced 1.27 dBsm. Finally, the radar absorbing material attachment at the front and back superstructure have been reduced 2.27 dBsm in terms of mean RCS value.

• Journal of electromagnetic engineering and science
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• v.11 no.3
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• pp.213-219
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• 2011

Simulative target generators are needed for testing and calibrating various radar systems. The generator in this study discriminates the transmitting frequency from a radar and simulates parameters like target range, range rate, and atmospheric attenuation using the digital RF memory technique. The simulative target echo is then sent to the radar for testing and evaluation. This paper proposes a novel architecture for controlling the digital RF memory so it continually writes ADC data to the memory and reads it for the DAC with increasing one step address in order to control the delay of target range in a simple way. The target echo is programmed according to various preprogrammed scenarios and is generated in real time using a wireless local area network (LAN). To analyze the detected and generated target information easily, the system times for the radar and simulative target generator are synchronized using a global positioning system (GPS).

• Journal of Power Electronics
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• v.13 no.3
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• pp.329-338
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• 2013

In this paper, the charging characteristics of series resonant type high voltage capacitor chargers considering the transformer stray capacitance have been studied. The principles of operation for the four operational modes and the mode changes for the four different switching frequency sections are explained and analyzed in the range of switching frequency below the resonant frequency. It is confirmed that the average charging currents derived from the above analysis results have non-linear characteristics in each of the four modes. The resonant current, resonant voltage, charging current, and charging time of this capacitor charger as variations of the switching frequency, series parallel capacitance ratio ($k=C_p/C_s$), and output voltage are calculated. From the calculation results, the advantages and disadvantages arising from the parallel connection of this stray capacitance are described. Some methods to minimize charging time of this capacitor charger are suggested. In addition, the results of a comparative test using two transformers whose stray capacitances are different are described. A 1.8 kJ/s prototype capacitor charger is assembled with a TI28335 DSP controller and a 40 kJ, 7 kV capacitor. The analysis results are verified by the experiment.

• International Journal of Oral Biology
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• v.36 no.3
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• pp.109-116
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• 2011

Periodontitis results from the activation of host immune and inflammatory defense responses to subgingival plaque bacteria, most of which are gram-negative rods with lipopoly-saccharides (LPSs) in their cell walls. LPSs have been known to induce proinflammatory responses and recently it was reported also that they induce the expression of microRNAs (miRNAs) in host cells. In our current study therefore, we aimed to examine and compare the miRNA expression patterns induced by the LPSs of major periodontopathogens in the human gingival epithelial cell line, Ca9-22. The cells were treated with 1 ${\mu}g$/ml of E. coli (Ec) LPS or 5 ${\mu}g$/ml of an LPS preparations from four periodontopathogens Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Aggregatibacter actinomycetemcomitans (Aa), and Fusobacterium nucleatum (Fn) for 24 h. After small RNA extraction from the treated cells, miRNA microarray analysis was carried out and characteristic expression profiles were observed. Fn LPS most actively induced miRNAs related to inflammation, followed by Aa LPS, Pi LPS, and Ec LPS. In contrast, Pg LPS only weakly activated miRNAs related to inflammation. Among the miRNAs induced by each LPS, miR-875-3p, miR-449b, and miR-520d-3p were found to be commonly up-regulated by all five LPS preparations, although at different levels. When we further compared the miRNA expression patterns induced by each LPS, Ec LPS and Pi LPS were the most similar although Fn LPS and Aa LPS also induced a similar miRNA expression pattern. In contrast, the miRNA profile induced by Pg LPS was quite distinctive compared with the other bacteria. In conclusion, miR-875-3p, miR-449b, and miR-520d-3p miRNAs are potential targets for the diagnosis and treatment of periodontal inflammation induced by subgingival plaque biofilms. Furthermore, the observations in our current study provide new insights into the inflammatory miRNA response to periodontitis.

• Corrosion Science and Technology
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• v.9 no.1
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• pp.39-47
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• 2010

Galvanic coupling between GECM(graphite epoxy composite material) and metallic materials can facilitate corrosion of metals and alloys because GECM is noble and electrically conductive. Galvanic corrosion is affected by many factors including metallic materials, area ratio, surface condition, and corrosivity. This work aims to evaluate the effect of area ratio on galvanic corrosion between GECM and several metals. In the case of glavanic coupling of carbon steel and Al to GECM, corrosion rate increased with increasing area ratio. Corrosion rate of sensitized STS 316S stainless steel decreased a little at an area ratio 1:1 but increased at an area ratio 30:1. It is considered to be due to that area ratio affects galvanic corrosion more in less corrosion resistant alloys. However, in case of STS 316 and Ti, galvanic coupling reduces corrosion rate by the formation of passive film.