• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅲ
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• pp.1549-1552
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• 2003

Semiconductor gas sensor using tin oxide as sensing material has been used to detect gases based on the fact that impedance of the sensing material varies when the gas sensor is exposed to the gases. This variation comprises of two parts. The first one is variation in resistance of the sensing material and the other is expressed in terms of the sensor capacitance variation. Normally, only variation of the sensor resistance is considered. In this paper, using AC measurement with a capacitor-coupled inverting amplifier circuit, both changes in the sensor resistance and variations in the sensor capacitance were investigated. These characteristics were represented as magnitude gain and phase shift of AC signal at a specific frequency after passing it through the sensor and the designed circuit. A two-stage artificial neural network, which utilized the information above, was employed to identify and quantify three combustible gases: methane, propane and butane. The network outputs were approximately proportional to concentrations of test gases with reasonable level of error.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권11호
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• pp.2160-2174
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• 2011

In this paper, a new technique for color reproduction based on color variation characteristics of digital camera under a dim light condition is proposed. Generally, photographers should adjust a camera exposure properly for obtaining an image with real color tone of subjects. Thus, in case of taking a picture under a dim light condition, the exposure time of a camera has to be relatively longer than the one under a bright light condition. Although images with real color tone of the subject are obtained, the images may get blurred due to the shaky hands of photographer holding the camera. In order to avoid the blur effect, an input image is captured from a camera set as a short exposure time under a dim light condition. Then we propose a method to reproduce color tone of the dim input image. To this end, color variation characteristics which represent color variations of a digital camera are first extracted by analyzing the Macbeth color checker images taken under various exposure values. Then, a color reproduction is performed by an estimation based on the color variation characteristics. Experimental results have shown that the proposed method has achieved better performance of color reproduction, compared with existing methods.

• 한국공간구조학회논문집
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• 제8권4호
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• pp.57-64
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• 2008

본 연구는 설치와 해체가 용이하여 간이식 구조에서 활용되는 시저스 전개형 구조에 관한 것으로, 입면상의 곡률변화 방법을 고찰하고 그에 따른 구조특성을 파악하고자 한 것이다. 먼저 시저스 구조의 입면상 곡률과 시저스부재의 내부절점 편심거리와의 관계를 식과 그래프를 이용하여 나타내었다. 이에 따라, 동일한 시저스부재에서 내부절점 편심거리를 조절하여 곡률을 변화시킬 수 있는 해석모델을 고찰함으로써, 곡률변화에 따른 시저스 구조부재들의 구조적 특성을 고찰하였다. 또한 고찰된 구성방식에 근거하여 실 모델을 제작하고 전개과정을 살펴봄으로써 실제 전개가능성을 검토하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.285-288
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• 2008

We analyzed evaporation data in the Japanese Ocean Flux Data Sets with Use of Remote Sensing Observations (J-OFURO) Ver.2. There exists huge evaporation in Gulf Stream, Kuroshio Extension, the ocean dessert and the southern part of the Indian Ocean. The temporal variation of evaporation is overwhelmingly large, of which the standard deviation is more than 120(mm), in the Kuroshio Extension region. Also, the result of harmonic analysis gives that this large variation is closely related to annual variation. In addition, the first EOF mode shows long-term variation showing the maximum amplitude between 1992 and 1994 and remarkable decrease after 1994, and large amplitude in the equatorial region and northeast of Australia. The second and third modes were strongly influenced by El Nino. Moreover, we compared J-OFURO2 evaporation product with other products. We used six kinds of data sets (HOAPS3 and GSSTF2 of satellite data, NRA1, NRA2, ERA40 and JRA25 of reanalysis data) for comparison. Most products show underestimation in the most regions, in particular, in the northern North Pacific, mid-latitudes of the eastern South Pacific, and high-latitudes of the South Pacific compared with J-OFUR02. On the other hand, JRA25 and NRA2 show large overestimation in the equatorial regions. RMS difference between NRA2 and J-OFURO2 in the Kuroshio Extension was significantly large, more than 120(mm).

• Computers and Concrete
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• 제26권5호
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• pp.385-395
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• 2020

The influence of combination of nano silica and silica fume, as partial cement replacement materials, on the properties of concrete has been studied through the measurement of compressive strength. The compressive strength of concrete in terms of mean, standard deviation and with-in-test coefficient of variation related to the variation in the nominated parameters have also been developed. The compressive strength data developed experimentally has been analyzed using normal-probability distribution and partial safety factors of composite concretes have been evaluated by using first order second moment approach with Hasofer Lind's method. The use of Nano silica and silica fume in concrete decreases the partial safety factor of concrete i.e., increase the reliability of concrete. The experimental results show that the properties of concrete having nano silica and silica fume in combination were better than that of a plain concrete. The SEM test results showing the level of Ca(OH)₂ in plain concrete and consumption level Ca(OH)₂ of concrete containing nano silica & silica fume have also been presented.

• 한국해양공학회지
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• 제30권4호
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• pp.235-242
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• 2016

In general, ship hull form design is carried out in two stages. In the first stage, the longitudinal variation of the sectional area curves is adapted from a similar mother ship to determine the volume distribution in ships. At this design stage, the initial design conditions of displacement, longitudinal center of buoyancy, etc. are satisfied and the global hydrodynamic properties of the structure are optimized. The second stage includes the local designing of the sectional forms. Sectional forms are related to the local pressure resistance in the fore- and aft-body shapes, cargo boundaries, interaction between the hull and propeller, etc. These relationships indicate that the hull sections need to be optimized in order to minimize the local resistance. The volumetric balanced (VOB) variation of ship hull forms has been suggested by Kim (2013) as a generalized, systematic variation method for determining the sectional area curves in hull form design. This method is characterized by form parameters and is based on an optimization technique. This paper emphasizes on an extensional function of the VOB considering a geometrical wave profile. We select a container ship and an LNG carrier to demonstrate the applicability of the proposed technique. Through analysis, we confirm that the VOB method, considering the geometrical wave profile, can be used as an efficient tool in the hull form design for ships.

• 대한건축학회논문집:계획계
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• 제35권1호
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• pp.83-92
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• 2019

Advertising signboards are designed for the visibility to affects recall and recognition of costumers. It is well know that the visibility from images is created by the value difference among colors. The research defines whether the background color combination of outdoor signboards is configured to maximize visibility, by a series of color value variation in complex commercial facilities. The subject of study is to examine how the visibility is made by the color combination since visibility cannot be obtained independently. Two steps of analysis were performed to confirm that the color composition of signboards was based on the color value difference. The first is to analyze that the entire colors of signboards are clearly categorized as different value groups. All components of colors, hue, value and chroma had been analyzed by color aesthetic measures to prove that the value variation has the only regularity and the principle of composition. The second step is a further verification with an ample amount of samples to determine whether series of signboards create a value altering pattern. The data for analysis is gained by colorimetric survey and the color data are used for exponentializing the degree of combining, which shows selective affinity between each pair colors.

• Journal of Plant Biotechnology
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• 제47권4호
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• pp.289-297
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• 2020

The genetic diversity of two subpopulations of Corynandra chelidonii, one of terrestrial and the other of aquatic environments, was measured with molecular markers, such as start codon targeted (SCoT), inter simple sequence repeats (ISSR), and random amplification of polymorphic DNA (RAPD). The traditional morphological traits such as habitat, habit, leaf morphology, the colour of the sepals and petals, number of stamens, and seed morphology formed the base for their realization as two varieties, C. chelidonii var. pallae and C. chelidonii var. chelidonii. The polymorphism between the two variants was 100% with the primers SCoT-2 and OPA-1 and 4, while maximum polymorphism was detected with ISSR-2, SCoT-3, and OPA-3. The study used, for the first time, more than one molecular marker to assess the genetic variation underscoring the morphological variation in Corynandra chelidonii (L.f.) Cochrane & Iltis. The study justifies the recognition of the two subpopulations of Corynandra chelidonii from aquatic and terrestrial environments as two distinct varieties, C. chelidonii var. pallae (Reddy & Raju) V.S.Raju and C. chelidonii var. chelidonii, respectively, based on the traditional taxonomic evidence.

• Journal of Microbiology and Biotechnology
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• 제33권3호
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• pp.348-355
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• 2023

Epifluorescence microscopy with image analysis was evaluated as a biofilm quantification method (i.e., quantification of surface area colonized by biofilms), in comparison with crystal violet (CV) staining. We performed different experiments to generate multispecies biofilms with natural and artificial bacterial assemblages. First, four species were inoculated daily in 16 different sequences to form biofilms (surface colonization, 0.1%-56.6%). Second, a 9-species assemblage was allowed to form biofilms under 10 acylase treatment episodes (33.8%-55.6%). The two methods comparably measured the quantitative variation in biofilms, exhibiting a strong positive relationship (R² ≥ 0.7). Moreover, the two methods exhibited similar levels of variation coefficients. Finally, six synthetic and two natural consortia were allowed to form biofilms for 14 days, and their temporal dynamics were monitored. The two methods were comparable in quantifying four biofilms colonizing ≥18.7% (R² ≥ 0.64), but not for the other biofilms colonizing ≤ 3.7% (R² ≤ 0.25). In addition, the two methods exhibited comparable coefficients of variation in the four biofilms. Microscopy and CV staining comparably measured the quantitative variation of biofilms, exhibiting a strongly positive relationship, although microscopy cannot appropriately quantify the biofilms below the threshold colonization. Microscopy with image analysis is a promising approach for easily and rapidly estimating absolute quantity of multispecies biofilms.

• Korean Journal of Mathematics
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• 제20권1호
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• pp.1-18
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• 2012

We study various relationships that exist among generalized conditional integral transform, generalized conditional convolution and generalized first variation for a class of functionals defined on K[0, T], the space of complex-valued continuous functions on [0, T] which vanish at zero.