• Journal of Korean Society on Water Environment
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• v.24 no.1
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• pp.44-53
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• 2008

To recognize the spatial and temporal variability of water temperature and dissolved oxygen in the Youngsan reservoir formed after dike construction, water temperature and dissolved oxygen data have been observed and analyzed from April, 2002 until March, 2003. As the results, certain stratifications were not distinctly observed in the Youngsan reservoir during summer, which was estimated due to the drainage characteristic from the Youngsan water gates. The yearly variation of water temperature in the Youngsan reservoir is shown seasonally ups and downs by the heat exchange between the atmosphere and the reservoir. On the other hand, dissolved oxygen and water temperature in the Youngsan reservoir have been shown inversed proportional correlation. As the calculation results of residence time and water exchange rate, it is considered that the feature of oxygen distribution is determined by the drainage characteristics caused the shortest residence time during summer, which also disturbed the formation of stratification in the Youngsan reservoir.

• Atmosphere
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• v.20 no.2
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• pp.91-100
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• 2010

In accordance with the time series of rainfall in summer (June, July and August) in South and North Korea for recent 28 years (1981-2008), rainfall is substantially increased in South Korea since 1996, while it is significantly decreased in North Korea. In particular, the decreasing tendency of rainfall in summer in North Korea is more definitely observed during the $2^{nd}$ rainy season (late August - mid September) in intraseasonal variation. Such a feature is also confirmed in the spatial distribution of oscillation pattern between South and North Korea on the basis of 1996 which is obtained by empirical orthogonal function analysis using the summer rainfall observed in all weather observation stations in South and North Korea. For the decreasing tendency of rainfall in North Korea, it is found that northeasterlies from anticyclonic circulation centered on around Baikal Lake weaken convective activity during summer. On the contrary, the increasing tendency of rainfall in South Korea is related to the strengthened cyclonic circulation in the southern region of China and accordingly, enhances southwesterlies in South Korea.

• Journal of IKEEE
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• v.24 no.1
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• pp.254-259
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• 2020

This paper is the implementation of the conversion system from image to music based on intentional synesthesia. The input image based on color, texture, and shape was converted into melodies, harmonies and rhythms of music, respectively. Depending on the histogram of colors, the melody can be selected and obtained probabilistically to form the melody. The texture in the image expressed harmony and minor key with 7 characteristics of GLCM, a statistical texture feature extraction method. Finally, the shape of the image was extracted from the edge image, and using Hough Transform, a frequency component analysis, the line components were detected to produce music by selecting the rhythm according to the distribution of angles.

• The Journal of Information Technology
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• v.7 no.3
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• pp.113-118
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• 2004

Recently, diagnosis techniques have been investigated to detect a partial discharge associated with a dielectric material defect in a high voltage electrical apparatus. However, the properties of detection technique of PD aren't completely understood because the physical process of PD. Therefore, this paper analyzes the process on Surface Discharge of Polymer Insulator using Wavelet transform. Wavelet transform provides a direct quantitative measure of spectral content in the time frequency domain. As it is important to develop a non-contact method for detecting the Contamination Degree, this research analyzes the electromagnetic waves emitted from PD using Wavelet transform. This result experimentally shows the process of PD as a two-dimensional distribution in the time-frequency domain. The method is shown to be useful for detecting prediction of contamination degree.

• KIEAE Journal
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• v.14 no.5
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• pp.75-80
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• 2014

An attempt has been made to prove the so-called 'feature accumulation theory'. It is the theory describing that people tend to feel the same space with more identifiable objects much larger than that with fewer objects. Applying this theory to our cognition of spatial size, this paper made an experiment. Students were asked that if the lecture room they are sitting becomes a module (module 1), then how large are the questioned spaces in the campus. The result was striking. Through the mental image processing, they answered that the library and the architecture building looks much smaller than they actually are, and more surprisingly the basketball field much more smaller than it really is. This experiment shows that there is a strong tendency by which people regard the space much larger when there are more occupiable or behavior-causing elements in the space. In the case of basketball field, since there is nothing that can be occupied, this open space is seen as a small space for the subjects. This line of cognitive perception can be applied to the practice of urban planning and architectural planning. With the same size of given space, we can make it feel more rich and larger.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8B
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• pp.1413-1423
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• 2000

Color distribution is changed according to the variation of illumination position and illumination color. Therefore, even if images are relevant each other, retrieval accuracy is degraded. In this paper, we propose the image retrieval method using color information excluded illumination component. The proposed dynamic range control method removes the shadow region generated by change of illumination position to increase the color discrimination power. To exclude the illuminant color, we use the diffuse reflection component of object and gray world assumption. The experimental results show that the color histogram method using color information excluded illuminant has higher retrieval accuracy than conventional color histogram using the color information of input image.

• Smart Structures and Systems
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• v.15 no.3
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• pp.699-715
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• 2015

A modal parameter based damage sensitive feature (DSF) is defined to mimic the relative change in any diagonal element of the stiffness matrix of a model of a structure. The damage assessment is performed in a statistical pattern recognition framework using empirical complementary cumulative distribution functions (ECCDFs) of the DSFs extracted from measured operational vibration response data. Methods are discussed to perform probabilistic structural health assessment with respect to the following questions: (a) "Is there a change in the current state of the structure compared to the baseline state?", (b) "Does the change indicate a localized stiffness reduction or increase?", with the latter representing a situation of retrofitting operations, and (c) "What is the severity of the change in a probabilistic sense?". To identify a range of normal structural variations due to environmental and operational conditions, lower and upper bound ECCDFs are used to define the baseline structural state. Such an approach attempts to decouple "non-damage" related variations from damage induced changes, and account for the unknown environmental/operational conditions of the current state. The damage assessment procedure is discussed using numerical simulations of ambient vibration testing of a bridge deck system, as well as shake table experimental data from a 4-story steel frame.

• Earthquakes and Structures
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• v.7 no.1
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• pp.57-82
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• 2014

The heritage value of the mixed wood-masonry 18th century Pombalino buildings of downtown Lisbon is recognized both nationally and internationally. The present paper focuses on the seismic assessment of global response and retrofitting of a typical Pombalino building by nonlinear static analyses, performed by the research software Tremuri, which is able to model 3D configurations. The structure is modelled using nonlinear beams for masonry panels, while in case of the internal walls (frontal walls) an original formulation has been developed in order to take into account their specific seismic behaviour. Floors are modelled as orthotropic membrane finite elements: this feature allows to simulate the presence of both flexible and rigid diaphragms, being the first ones more representative of the original state while the second ones of retrofitted configurations. Seismic assessment has been evaluated by applying nonlinear static procedure and comparing the performance of different configurations (by considering various retrofitting strategies). Finally, assuming a lognormal cumulative distribution, fragility curves are obtained to be representative of Pombalino buildings: the most important application of such curves is for seismic risk and loss estimation analyses.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.3
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• pp.747-756
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• 2015

Brown alga Undaria peterseniana has been interested in the commercial scale aquaculture for warm water species development in southern coastal area of Korea. However, this species was classified an endangered species caused by a decrease in habitat and natural population. In this study, inhabit characteristics of U. peterseniana was investigated in their natural habitat of Ulleung Island, Korea. The U. peterseniana population was occurred dense patches at 20~30m depth. Total length of the alga reached 1.0~2.0m and the largest width ranged 10.0~35.0cm during the study. In 2013, habitats of this species increased two sites compared with the previous year and their distribution extended to low depth (10m) of coastal area. In long-term data, seawater temperature revealed a continuous increment by strong going north of East Korea Warm Current or Ulleung Warm Eddy turning around the coast of Ulleung Island. It suggested that habitat extension of U. peterseniana may be caused by suitable settlement condition and increase of warm water around the coastal area. Current studies of this species may be continuously required in the possibility of fisheries resources as aquaculture species and index species of increment of water temperature at the fixed monitoring site in East Sea. This is the first study to research ecological feature U. peterseniana population at the natural habitat of Ulleung Island.

• Journal of the Korean Magnetics Society
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• v.24 no.2
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• pp.66-69
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• 2014

The spreading tube of X-ray cathode tube displayed with an electromagnetic finite element method was designed. To analyze a feature design and the concrete coordinate performance of soft X-ray tube modeling, the orbit of electron beam was simulated by OPERA-3D SW program. The fixed conditions were the applied voltage, the temperature, the work function of thermal electron between cathode and anode of tungsten. Through the analysis of distribution of electron beam and the variation of dividing region, the design of soft X-ray spreading tube equipped with two cross filaments was optimized.