• Journal of Korean Society for Geospatial Information Science
• /
• v.25 no.2
• /
• pp.67-74
• /
• 2017

The D-InSAR is a technique for precisely measuring the subsidence of subsidence using difference of two SAR images. In order to calculate the subsidence using D-InSAR, a high coherence between master image and the slave image is essential. Since the existing D-InSAR method calculates the displacement based on the total coherence, the accuracy of the subsidence is lowered when the coherence map contains mountains or bare-land. In order to solve this problem, in this study, a point having a temporal coherence and spatial coherence of 0.7 or more was extracted to form TIN, and the subsidence was calculated based on this TIN. In addition, we compared the existing D-InSAR technique with the new D-InSAR technique considering spatial and temporal coherence. As a result, the new D-InSAR technique showed smaller standard deviation, relative variance, variation coefficient and quadrature deviation than the existing D-InSAR technique. It is also easy to grasp the trend of the subsidence.

• Communications of Mathematical Education
• /
• v.35 no.1
• /
• pp.75-96
• /
• 2021

This study aims to drive the implications for the structure of mathematics curriculum documents in Korea, exploring the coherence in the documental structure of the IB DP mathematics curriculum, which is gaining international attention. The documents of the IB DP mathematics curriculum were analyzed based on the coherence of external and internal structures. First, the curriculum was consistently described by subject and topic, presenting the table of contents and structure of the documents in the same format. Second, the descriptions of the curriculum between subjects and within the subjects were consistent through the same composition of the subject and assessment methods, the presentation of big ideas, and 'Guidance, clarification and syllabus links'. Third, in 'Connections', the curriculum documents were described with coherence through linking with other subjects by describing the connection plan with the real-world contexts, other subjects, and the 'Theory of Knowledge' in the IB curriculum. Based on these findings and implications for the concreteness and consistency of the components in mathematics curriculum documents, we propose the coherence between the presentation of subject areas and assessment methods of the revised curriculum, and the implementation of coherence in documental structure through links with other subjects.

• Journal of the Korean Data and Information Science Society
• /
• v.25 no.4
• /
• pp.807-817
• /
• 2014

This paper considers multivariate time series modelling of PM10 data in Korea collected from 2008 to 2011. We consider both temporal and spatial dependencies of PM10 by applying the sparse vector autoregressive (sVAR) modelling proposed by Davis et al. (2013). It utilizes the partial spectral coherence to measure cross correlation between different regions, in turn provides the sparsity in the model while balancing the parsimony of model and the goodness of fit. It is also shown that sVAR performs better than usual vector autoregressive model (VAR) in forecasting.

• Korean Journal of Remote Sensing
• /
• v.26 no.5
• /
• pp.497-510
• /
• 2010

In this study, comparisons of the backscattering coefficients and the coherence values which had been extracted from SAR (Synthetic Aperture Radar) images such as JERS-1, ENVISAT and ALOS satellites with surface roughness, surface geometric and soil moisture content were carried out. As the results of analysis using the backscattering coefficient and coherence values from SAR images, the coherence was shown high in the region containing more of mud fraction due to higher viscosity of fine grain-size. A lot of tidal channels were well developed in the Ganghwa tidal flat, affecting the drainage of seawater and subsequent soil moisture content by exposure time of tidal flat. The backscattering coefficient. consequently, appeared to be lower in sand flat and mix flat with decrease of soil moisture. In contrast, most mud flats were distributed at high elevation so that soil moisture was not much influenced by seawater. The backscattering coefficient in mud flat seemed to have a relationship with the density of tidal channel. In addition, lowering backscattering coefficients in the all Ganghwa tidal flat was observed when surface remnant water increased according to the amount of rainfall. The correlation between backscattering coefficient, coherence and sediment environment factors in the Ganghwa tidal flat was investigated. In the future, more quantitative spatial analysis will be helpful to well understand the sedimentary influence of various sediment environment factors.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.6
• /
• pp.48-55
• /
• 2009

The feedback interference channels are those made through the multipaths that are built by moving and stationary objects around transmit and receive antennas mounted at the same point. This paper describes the method to measure the feedback interference channels in the rural regions and sides of highways and the analysis on channel characteristic parameters. Using the measured samples, we estimated scattering functions, delay power spectra, and Doppler power spectra, and we analyzed the channels using eight parameters including coherence bandwidth, coherence time, maximum excess delay, average excess delay, rms delay spread, Doppler shift, Doppler spread, and spread factor, and delay and Doppler cumulative distributions. Even though many observations are made, note that the feedback signals of high Doppler frequencies and large energy are observed in the sides of highways due to high speed vehicles while low Doppler frequencies occurred in the rural region due to rare traffic.

• Journal of Korea Multimedia Society
• /
• v.2 no.4
• /
• pp.409-418
• /
• 1999

The fractal image compression is based on the self-similarity that some area in an image exhibits a very similar shape with other areas. This compression technique has very long encoding time although it has high compression ratio and fast decompression. To cut-off the encoding time, most researches have restricted the search of domain blocks for a range block. These researches have been mainly focused on the coherence between a domain block and a range block, while they have not utilized the coherence among range blocks well. Therefore, we give an analysis on the coherence among range blocks in order to develope an efficient fractal Image compression algorithm. We analysis the range blocks according to not only measures for defining the range block coherence but also threshold of each measure. If these results are joined in a prior work of other fractal compression algorithms, it will give a great effectiveness in encoding time.

• Science of Emotion and Sensibility
• /
• v.16 no.4
• /
• pp.527-534
• /
• 2013

In this study, we analyzed spatial-frequency relationship related brain function for change of the time during attentional visual stimulus through the analysis of Coherence. With experimentation about ERP(Event Related Potential)data, it revealed that change of the phase synchronization between different scalp locations at ${\theta}$, ${\alpha}$ band. ERP between left and right frontal lobes, between the frontal and central lobes showed the phase synchronization at the P100, N200, ERP between the frontal and occipital lobes showed the phase synchronization at the P300 related information of visual stimulus. Compared to STFT using the window of a fixed length, CWT is able to multi-resolution analysis with the adjustment of parameters of mother wavelet. Thus, coherence results with CWT was found to be effective for analysis of time-varying spatial-frequency relationship in ERP. The phase synchronization for inattentional visual stimulus was not observed.

• Aerospace Engineering and Technology
• /
• v.8 no.1
• /
• pp.132-137
• /
• 2009

This study has regard to classification by using multi-temporal SAR data. Multi-temporal JERS-1 SAR images are used for extract the land cover information and possibility. So far, land cover information extracted by high resolution aerial photo, satellite images, and field survey. This study developed on multi-temporal land cover status monitoring and coherence information mapping can be processing by L band SAR image. From July, 1997 to October, 1998 JERS SAR images (9 scenes) coherence values are analyzed and then extracted land cover information factors, so on. This technique which forms the basis of what is called SAR Interferometry or InSAR for short has also been employed in spaceborne systems. In such systems the separation of the antennas, called the baseline is obtained by utilizing a single antenna in a repeat pass.

• Research in Community and Public Health Nursing
• /
• v.31 no.3
• /
• pp.223-233
• /
• 2020

Purpose: The purpose of this study was to construct a model that describes the health related quality of life in working women with preschool children and to verify the goodness of fitness of the model. Methods: The data were collected with a structured self-report questionnaire from 483 working women with preschool children. Results: The modified model showed a reasonable fitness to the data. Social support, job satisfaction, parenting stress, sense of coherence and depression accounted for 78% of the health related quality of life in working women with preschool children. Conclusion: This study suggests that the health related quality of life in working women with preschool children can be improved by reducing parenting stress and depression level, and by increasing social support, job satisfaction, and sense of coherence. Depression can also be managed by reducing parenting stress and by increasing job satisfaction and sense of coherence. Based on the results of this study, it is necessary to develop intervention programs to increase the health related quality of life or to decrease depression in working women.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.6 no.3
• /
• pp.431-438
• /
• 1996

Transmission electron microscopy has been used to investigate the microstructure of hot-pressed $TiB_{2}$. Thin foil specimens, prepared by conventional ion beam thinning, revealed many features which originated from the crystallographic anisotropy of hexagonal $TiB_{2}$. It was observed that in these specimens Fe-impurities are precipitated to form secondary Fe-rich phases at grain triple edges, in grain boundaries and sometimes in-grain. These Fe-rich precipitates were characterised by their coherence or semi-coherence to a favourably oriented grain at a grain triple edge or grain boundaries or to the matrix $TiB_{2}$ phase.