• Journal of the Korean Magnetic Resonance Society
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• v.24 no.4
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• pp.96-103
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• 2020

A new NMR method to monitor solvent-localized NMR signals in the two-phase liquid system is suggested. This method based on intermolecular single-quantum coherence (iSQC). Here, we exploited the feature of the local action of distant dipolar field (DDF) effect in order to filter out specific NMR signals dissolved in different solvents. This solvent specific iSQC spectroscopy was carried out on a model two-phase liquid system (D-glucose in water/palmitic acid in chloroform), and showed solvent-localized NMR signals. We believe our approaches might be useful in metabolic analysis such as two-phase liquid extraction scheme for labile chemical species.

• The Journal of the Acoustical Society of Korea
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• v.20 no.8
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• pp.44-57
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• 2001

This paper analyses the performance of FFTSA (Fast Fourier Transform Synthetic Aperture) in the effects of temporal coherence and oscillatory towed course, which is one of the techniques for passive synthetic aperture SONAR process using linearly distributed towed array. Also this paper proposes the FFTSA technique using towed array having conformal shape to alleviate the performance degradation for estimating the incident angle under inconsistent under water environments. And this paper analyses the performance of the proposed FFTSA technique making use of conformal structure throughout exhaustive computer simulations.

• Wind and Structures
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• v.9 no.5
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• pp.387-396
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• 2006

This paper presents the wind characteristics of Typhoon Dujuan as measured at a 50 m guyed mast in Hong Kong. The basic wind speed, wind direction and turbulent intensity are studied at two measurement levels of the structure. The power spectral density of the typhoon is compared with the von Karman prediction, and the coherence between wind speeds at the two measurement levels is found to This paper presents the wind characteristics of Typhoon Dujuan as measured at a 50 m guyed mast in Hong Kong. The basic wind speed, wind direction and turbulent intensity are studied at two measurement levels of the structure. The power spectral density of the typhoon is compared with the von Karman prediction, and the coherence between wind speeds at the two measurement levels is found to compare with Davenport's prediction. The effect of typhoon Dujuan on the response of the structure will be discussed in a companion paper (Law, et al. 2006).with Davenport's prediction. The effect of typhoon Dujuan on the response of the structure will be discussed in a companion paper (Law, et al. 2006).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.2
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• pp.1-8
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• 1987

Recently, as subway traffic have been increased, vibration of each parts of subway influence on structures above subway tunnel. This paper presents a new method to reduce which was generated by subway traffic. By comparing directional coherence relationship of X, Y, Z-axis and vibrational coherence relationship of spherical signal which was unified by three directional signals, effective vibration diminishing method was proposed. It can be found that locomotive vibration(specially 1-2Hz) have the worst effect on the vibration of structures and the vibration of subway box ranked 2nd, the vibration of earth ranked 3rd.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.5 s.305
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• pp.1-10
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• 2005

Content-based image retrieval systems are being actively investigated owing to their ability to retrieve images based on the actual visual content rather than by manually associated textual descriptions. In this paper, we propose a novel approach for image retrieval based on edge structural features using edge correlogram and color coherence vector. After color vector angle is applied in the pre-processing stage, an image is divided into two image parts (high frequency image and low frequency image). In low frequency image, the global color distribution of smooth pixels is extracted by color coherence vector, thereby incorporating spatial information into the proposed color descriptor. Meanwhile, in high frequency image, the distribution of the gray pairs at an edge is extracted by edge correlogram. Since the proposed algorithm includes the spatial and edge information between colors, it can robustly reduce the effect of the significant change in appearance and shape in image analysis. The proposed method provides a simple and flexible description for the image with complex scene in terms of structural features of the image contents. Experimental evidence suggests that our algorithm outperforms the recently histogram refinement methods for image indexing and retrieval. To index the multidimensional feature vectors, we use R*-tree structure.

• Korean Journal of Social Welfare Studies
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• v.49 no.2
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• pp.181-209
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• 2018

This study aims to examine the relationship between physical environment and depression symptoms of middle-aged and older adults in metro city. To verify correlates of community environment and depression, mediating effect model structured by social capital and sense of coherence(SOC) were used. For the purpose, a survey was conducted aged 48 - 70 from the local community centers and senior welfare centers in Seoul, and the total collected cases were 331. After data cleaning, total 309 cases were used. The structured equation modeling applied to analyse the direct and indirect effects. The findings were followed : First, the community environment did not directly affect level of depression. Second, in the indirect effect analysis, social capital was not statistically significant, thus indirect effect was confirmed only through the SOC. To be specific, the higher the satisfaction of the physical environment increased SOC, and decreased the level of depression. The results of this study shed lights on practical interventions to promote mental health of the middle-aged and older adults those who are exposed to poor community environment.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.1
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• pp.1-8
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• 2011

In this paper, a water tank experiment using Binary Frequency Shift Keying (BFSK) method for text transmission performance by water surface fluctuation is conducted. Water surface fluctuation and delay spread which affect the channel coherence bandwidth is a limiting factor in underwater acoustic communication. The amplitude fluctuation and delay spread the smooth surface and fluctuation surface, were identified. The effective delay spread of both cases are 5ms, 4ms corresponding to the coherence bandwidth of 200Hz, 250Hz, respectively. The bit error rate of BFSK modulated text transmission is about $10^{-4}$ in less than 200bps in smooth surface but less than 250bps in fluctuation surface. Therefore, this experiment shows that the water surface fluctuation is important factor determining the performance of the underwater acoustic transmission.

• Architectural research
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• v.4 no.1
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• pp.7-16
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• 2002

In order to examine theoretical underpinnings of preference for built forms, 129 subjects are asked to rate a series of 9 slides of residential houses depicting a wide range of architectural styles on a 5 point scale, for coherence, complexity, excitement, familiarity, and natural harmony, respectively. Based on Lee's (2002a, 2002b) two previous studies addressing the issue of aesthetic beauty evaluation for man-made creatures (e.g., residential housing scenes), this study summarizes several meaningful findings. As reported by all the subjects, first, both "desire to visit" and "desire to live in" turned out to be a good predictor of preference as the two measures are highly correlated in statistically significant levels (99.9%). People who desire to visit a spot are more likely to desire to live in it. Second, Pearson's correlations showed that coherence is the opposite end of complexity. The more likely a housing setting is hanging together, the less likely it looks to be complex. Overall, though, it is not clear that the two variables work directly in that way, as weighted on preference ratings. That is, coherence and complexity are likely to be totally two independent systems that affect the ratings of preference. Third, both excitement and environmental sensitivity (e.g., harmony of a house with its surrounding nature) most highly account for the preference for various housing scenes, while familiarity has only a little effect on preference ratings. Possibly, people like or dislike a visual thing, no matter how much they are familiar with it. Finally, this study suggested that design professionals could communicate effectively with their clients if sets of visual standards as an appropriate communication tool for better design are properly established.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.6
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• pp.19-28
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• 2007

The purpose of this paper is to present a new measure for fingerprint image quality assessment that has a considerable effect on evaluation of fingerprint databases. This paper introduces a hybrid segmentation method for measuring an image quality and evaluates the experimental results using various fingerprint databases. This study compares the performance of the proposed hybrid segmentation using variance and coherence of fingerprints against the NIST's NFIQ program. Although NFIQ is a most widely used tool, it classifies the image quality into 5 levels. However, the proposed hybrid method is developed to be conformant to the ISO standards and accordant to human visual perception. The experimental results demonstrate that the hybrid method is able to produce finer quality measures.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.7
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• pp.1127-1140
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• 1997

With the study for identifying the transmission characteristics of vibration and noise generated by operating engine system of a vehicle, recently many engineers have studied actively the reduction of vibration and noise inducing uncomfortableness to the passenger. In this study, output noise was analyzed by multi-dimensional spectral analysis and vector synthesis method. The multi-dimensional analysis method is very effective in case of identification of primary source, but this method has little effect on suggestion for interior noised reduction. For compensation of this, vector synthesis method was used to obtain effective method for interior noise reduction, after identifying primary source for output noise. In this paper, partial coherence function of each input was calculated to know which input was most coherent to output noise, then with simulation of changes for input magnitude and phase by vector synthesis diagram, the trends of synthesized output vector was obtained. As a result, the change of synthesized output vector could be estimated.