• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.405-407
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• 2003

An attempt has been in this study to delineate the characteristics of spectral signatures of the vegetation in terms of various VIs, particularly made the Normalized Difference Vegetation Index(NDVI), Modified Soil Adjusted Vegetation Index2(MSAVI2) and Enhanced Vegetation Index(EVI). Multitemporal SPOT-4 VEGETATION data from 1998 to 2002 have been used for the analysis. They have been compared with each other for their similarities and differences. The correlations between the vegetation indices observed at various degree of vegetation coverage during their different stages of growth were examined. All of the VIs have shown qualitative relationships to variations in vegetation. Apparently, the NDVI and MSAVI2 are highly correlated for all of the temporal changes, representing the different stages of phenology.

• Ocean Science Journal
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• v.40 no.4
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• pp.201-208
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• 2005

An accurate particle tracking method for a finite difference method model is developed using a constant acceleration method. Being assumed constant temporal and spatial gradients, the new method permits temporal-spatial variability of particle velocity. Test results in a solid rotating flow show that the new method has second-order accuracy. The performance of the new method is compared with that of other methods; the first-order Euler forward method, and the second-order Euler predictor-corrector method. The new method is the most efficient method among the three. It is more accurate and efficient than the other two.

• Journal of Forest and Environmental Science
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• v.33 no.2
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• pp.122-129
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• 2017

Understanding how future climate conditions will be impact on the biodiversity and species composition is important, because biodiversity becomes more important in environment assessment. To understand the biological changes including diversity and species composition over time (temporal variation within a year), the species diversity and composition of ground beetles were investigated in two well-preserved areas in the Sobaeksan National Park using pitfall traps. In addition, relationships between ground beetles and environmental variables were studied by considering temporal variation. We collected 2,146 ground beetle specimens representing 45 species, and individual-based rarefaction curves indicated that similar species richness was found between Geumseon Valley (GV) and Namcheon Valley (NV). The Bray-Curtis matrix comparisons between study sites were characterized by similar ground beetles sample heterogeneity, while temporal variations in abundance, species richness, and ${\beta}-diversity$ of ground beetles showed rather difference over time according to location of study sites. In GV site, minimum temperature was selected as the best predictor for abundance, species richness, and ${\beta}-diversity$ of ground beetles, while those relationships in NV site were more complicated. In conclusion, our study suggests that understanding the different response of ground beetles to climatic variables related to local habitat conditions is important to predict the effect of climate change on biological communities.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1041-1047
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• 2023

Temporal bone CT, which is a high-resolution CT, uses a high tube voltage and a thin section thickness, so the scan dose is higher than that of adjacent areas. Accordingly, we applied changes to the reconstruction algorithm among the test conditions to find an algorithm with excellent sensitivity to lesions while reducing the test dose, and investigated its significance and the possibility of providing basic clinical data. As a result, when the tube voltage was lowered to 100 kVp and applied, the dose was reduced by about 35.6%, and when the definition algorithm was applied to the raw data acquired at 100 kVp, the SNR and CNR were excellent, and a statistically significant difference was shown when compared to other algorithms(p<0.05). And as a result of comparing structural similarity, the SSIM index was analyzed as 0.776, 0.813, and 0.741 for each ROI. Therefore, we believe that applying algorithm changes to temporal bone CT scans can partially reduce the dose generated from CT scans and are very meaningful in terms of basic clinical data.

• Phonetics and Speech Sciences
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• v.7 no.4
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• pp.131-138
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• 2015

The initial syllables of a pair of Sino-Korean words are generally differentiated in their meaning by either short or long durations. They are realized differently by the dialect and generation of speakers. Recent research has reported that the temporal distinction has gradually faded away. The aim of this study is to examine whether college students with Kyungsang dialect made the distinction temporally using a statistical method of Mixed Effects Model. Thirty students participated in the recording of five pairs of Korean words in clear or casual speaking styles. Then, the author measured the durations of the initial syllables of the words and made a descriptive analysis of the data followed by applying Mixed Effects Models to the data by setting gender, length, and style as fixed effects, and subject and syllable as random effects, and tested their effects on the initial syllable durations. Results showed that college students with Kyungsang dialect did not produce the long and short syllables distinctively with any statistically significant difference between them. Secondly, there was a significant difference in the duration of the initial syllables between male and female students. Thirdly, there was also a significant difference in the duration of the initial syllables produced in the clear or casual styles. The author concluded that college students with Kyungsang dialect do not produce long and short Sino-Korean syllables distinctively, and any statistical analysis on the temporal aspect should be carefully made considering both fixed and random effects. Further studies would be desirable to examine production and perception of the initial syllables by speakers with various dialect, generation, and age groups.

• Journal of Haehwa Medicine
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• v.15 no.1
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• pp.1-9
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• 2006

For this study, we carried out dementia assessment examination of 74 patients with memory disturbance who have come to Cheongju oriental hospital of Daejeon university from April 2005 to February 2006. This study classified the patients as none-dementia(ND), questionable dementia(QD), and dementia(DA) groups and analyzed the result of examination. As a result, the following conclusion was drawn. 1. Among the 3 groups, there was no significant differences in the sex distribution. But according to age distribution, the age of QD and DA groups showed significant difference from that of ND group. 2. MMSE-K and HDS-K scores showed the significant differences among all groups, and 7 MS result showed the significant difference between ND and the other groups. 3. The DA group significantly got lower scores than ND group in the items of the MMSE-K, Orientation, Registration, Recall, Attention, Copy two pentagons and Comprehension. Especially, significant difference also was shown in the orientation item between QD and DA groups. 4. The scores in the items of 7 MS, Benton temporal orientation, Enhanced cued recall and Clock drawing showed significant difference among all groups. Category fluency score showed significant difference between ND and the other groups. 5. The results of Brain CT and clinical chemistry test didn't show significant difference among all groups.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.365-372
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• 2016

Recently, UWAC(: UnderWater Acoustic Communication) has been studied by many scholars and researchers. There are several method to estimate the time-difference between the two signals such estimating as the arrival time of the first non-background segment in both signals and calculate the temporal difference, calculating the cross-correlation between the two signal to infer the time-lagged, and estimating the phase delay to infer the time difference. In this paper, we present estimating method by the phase delay to infer the time difference in two signals.

• Proceedings of the IEEK Conference
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• 2000.11c
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• pp.137-140
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• 2000

In this paper, we propose as new algorithm for the selection of key frames in a given video. For the selected key frames to be well defined, the selected key frames need to spread out on the whole temporal domain of the given video and guaranteed not to be duplicate. For this purpose, we take the first frame of each shot of the video as the candidate key frame to represent the video. To reduce the overall processing time, we eliminate some candidate key frames which are visually indistinct in the histogram difference. The key frames are then selected using a clustering processing based on the singly linked hierarchical tree. To make the selected key frames be distributed evenly on the whole video, the deviation and time difference between the selected key frames are used. The simulation results demonstrate that our method provides the better performance compared with previous methods.

• Journal of applied mathematics & informatics
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• v.40 no.1_2
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• pp.25-45
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• 2022

In this study, the non-standard finite difference method for the numerical solution of singularly perturbed parabolic reaction-diffusion subject to Robin boundary conditions has presented. To discretize temporal and spatial variables, we use the implicit Euler and non-standard finite difference method on a uniform mesh, respectively. We proved that the proposed scheme shows uniform convergence in time with first-order and in space with second-order irrespective of the perturbation parameter. We compute three numerical examples to confirm the theoretical findings.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.2
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• pp.113-130
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• 2004

Most multimedia data contain text to emphasize the meaning of the data, to present additional explanations about the situation, or to translate different languages. But, the left makes it difficult to reuse the images, and distorts not only the original images but also their meanings. Accordingly, this paper proposes a support vector machines (SVMs) and spatiotemporal restoration-based approach for automatic text detection and removal in video sequences. Given two consecutive frames, first, text regions in the current frame are detected by an SVM-based texture classifier Second, two stages are performed for the restoration of the regions occluded by the detected text regions: temporal restoration in consecutive frames and spatial restoration in the current frame. Utilizing text motion and background difference, an input video sequence is classified and a different temporal restoration scheme is applied to the sequence. Such a combination of temporal restoration and spatial restoration shows great potential for automatic detection and removal of objects of interest in various kinds of video sequences, and is applicable to many applications such as translation of captions and replacement of indirect advertisements in videos.