• Title/Summary/Keyword: Temporal stability analysis

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Persistent Scatterer Selection and Network Analysis for X-band PSInSAR (X-band PSInSAR를 위한 고정산란체 추출 및 네트워크 분석 기법)

  • Kim, Sang-Wan;Cho, Min-Ji
    • Korean Journal of Remote Sensing
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    • v.27 no.5
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    • pp.521-534
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    • 2011
  • The high-resolution X-band SAR systems such as COSMO-SkyMED and TerraSAR-X have been launched recently. In addition KOMPSAT-5 will be launched in the early of 2012. In this study we developed the new method for persistent scatterer candidate (PSC) selection and network construction, which is more suitable for PSInSAR analysis using multi-temporal X-band SAR data. PSC selection consists in two main steps: first, selection of initial PSCs based on amplitude dispersion index, mean amplitude, mean coherence. second, selection of final PSCs based on temporal coherence directly estimated from network analysis of initial PSCs. To increase the stability of network the Multi- TIN and complex network for non-urban area were addressed as well. The proposed algorithm was applied to twenty-one TerraSAR-X SAR of New Orleans. As a result many PSs were successfully extracted even in non-urban area. This research can be used as the practical application of KOMPSAT-5 for surface displacement monitoring using X-band PSInSAR.

Spatial Variability of Soil Moisture and Irrigation Scheduling for Upland Farming (노지 작물의 적정 관개계획을 위한 토양수분의 공간변이성 분석)

  • Choi, Yonghun;Kim, Minyoung;Kim, Youngjin;Jeon, Jonggil;Seo, Myungchul
    • Journal of The Korean Society of Agricultural Engineers
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    • v.58 no.5
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    • pp.81-90
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    • 2016
  • Due to droughts and water shortages causing severe damage to crops and other vegetations, much attention has been given to efficient irrigation for upland farming. However, little information has been known to measure soil moisture levels in a field scale and apply their spatial variability for proper irrigation scheduling. This study aimed to characterize the spatial variability and temporal stability of soil water contents at depths of 10 cm, 20 cm and 30 cm on flat (loamy soil) and hill-slope fields (silt-loamy soil). Field monitoring of soil moisture contents was used for variogram analysis using GS+ software. Kriging produced from the structural parameters of variogram was applied for the means of spatial prediction. The overall results showed that the surface soil moisture presented a strong spatial dependence at the sampling time and space in the field scale. The coefficient variation (CV) of soil moisture was within 7.0~31.3 % in a flat field and 8.3~39.4 % in a hill-slope field, which was noticeable in the dry season rather than the rainy season. The drought assessment analysis showed that only one day (Dec. 21st) was determined as dry (20.4 % and 24.5 % for flat and hill-slope fields, respectively). In contrary to a hill-slope field where the full irrigation was necessary, the centralized irrigation scheme was appeared to be more effective for a flat field based on the spatial variability of soil moisture contents. The findings of this study clearly showed that the geostatistical analysis of soil moisture contents greatly contributes to proper irrigation scheduling for water-efficient irrigation with maximal crop productivity and environmental benefits.

Reliability and Validity of the Malay Version of the Breast-Impact of Treatment Scale (MVBITS) in Breast Cancer Women undergoing Chemotherapy

  • Zainal, Nor Zuraida;Shuib, Norley;Bustam, Anita Zarina;Sabki, Zuraida Ahmad;Guan, Ng Chong
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.463-468
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    • 2013
  • Background: Body image dissatisfaction among breast cancer survivors has been associated with psychological stress resultant from breast cancer and resultant surgery. This study aimed to examine the psychometric properties of the Malay Version of the Breast-Impact of Treatment Scale (MVBITS) and to investigate the associations of retained factors with the Hospital Anxiety and Depression Scale (HADS) and the Rosenberg Self-Esteem Scale (RSES). Materials and Methods: The MVBITS was 'forward-backward' translated from English to Malay and then administered to 70 female breast cancer patients who came to the Oncology Clinic of University Malaya Medical Centre, Kuala Lumpur, Malaysia to undergo chemotherapy. Principal component analysis (PCA) with varimax rotation was performed to explore the factor structure of the MVBITS. Associations of retained factors were estimated with reference to Spearman correlation coefficients. Results: The internal consistency reliability of MVBITS was good (Cronbach's alpha 0.945) and showed temporal stability over a 3-week period. Principal component analysis suggested two factors termed as 'Intrusion' and 'Avoidance' domains. These factors explained 70.3% of the variance. Factor 1 comprised the effects of breast cancer treatment on the emotion and thought, while Factor 2 informed attempts to limit exposure of the body to self or others. The Factor 1 of MVBITS was positively correlated with total, depression and anxiety sub-scores of HADS. Factor 2 was positively correlated with total and anxiety sub-scores of HADS. MVBITS was also positively correlated with the RSES scores. Conclusions: The results showed that the Malay Version of Breast-Impact of Treatment Scale possesses satisfactory psychometric properties suggesting that this instrument is appropriate for assessment of body change stress among female breast cancer patients in Malaysia.

Comparative Analysis of Transgene Copy Numbers and Expression Characteristics across Multiple Transgenic Marine Medaka Oryzias dancena Strains carrying the β-Actin Promoter-Driven GFP Reporter

  • Cho, Young Sun;Lee, Sang Yoon;Vu, Nguyen Thanh;Kim, Dong Soo;Nam, Yoon Kwon
    • Fisheries and Aquatic Sciences
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    • v.18 no.2
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    • pp.183-193
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    • 2015
  • Several transgenic marine medaka Oryzias dancena strains harboring a green fluorescent protein (GFP) reporter construct regulated by an endogenous ${\beta}$-actin promoter were established and their expression characteristics in relation to transgene copy numbers were examined in 21 transgene genotypes. Most of the transgenic strains displayed transgene insertion patterns typical of microinjection-mediated introduction of foreign DNA into fish embryos, characterized by the random integration of multiple transgene copies (ranging from 1 - 282 copies per cell), often accompanied by the formation of concatemer(s), as assessed by genomic Southern blot hybridization analysis and qPCR. Transgenic strains showed ubiquitous and continued temporal and spatial expression patterns of the transgenic GFP during most of their life cycle, from the embryonic stage to adulthood, enabling assessment of the expression pattern of the endogenous ${\beta}$-actin gene. However, a comparative evaluation of transgene copy numbers and expression levels showed that copy number-dependent expression, the stability of the ubiquitous distribution and expression efficiency per transgene copy varied among the transgenic strains. Fluorescence expression levels were positively correlated with absolute transgene copy numbers, whereas the expression efficiency per transgene copy was inversely related to the number of transgene integrant copies. Data from this study will guide the selection of potentially desirable transgenic strains with ubiquitous expression of a fluorescent transgene, not only in this marine medaka species but also in other related model fish species.

Spatio- and temporal patterns of benthic environment and macrobenthos community on subtidal soft-bottom in Chonsu Bay, Korea (천수만 조하대 연성저질의 저서환경과 저서동물 군집의 시${\cdot}$공간적 양상)

  • PARK Heung-Sik;LIM Hyun-Sig;HONG Jae-Sang
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.33 no.3
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    • pp.262-271
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    • 2000
  • This study was carried out to clarify the spatial and temporal patterns of benthic environments and macrobenthos on the subtidal soft-bottom in Chonsu Bay. Seasonal surface water temperature was similar to the bottom layer, but freshwater discharges into the outlets dereased the surface salinity around the dyke in summer. Bottom dissolved oxygen was decreased deeply around the dyke and created the de-oxygenated layer during summer. Sediment grain size was consisted of finer at the neighboring of the dyke than the mouth of the bay. Organic matters including the sediment were decreased at the mouth of the bay. A total of 311 species ($769\;ind./m^2$) were identified. Polychaetes were the most abundant faunal group in the number of species and densities. The number of species revealed the spatial patterns that it was higher in the mouth of the bay, and their densities showed seasonal changes by mass recruitment occurred at the most of the area in summer, At this time, opportunistic species, Lumbrineris iongifolia and Theora fragilis, were also recruited massively. Chonsu Bay were classified into five station groups by the cluster analysis. The dominant species around the dyke were composed to opportunistic species, those in middle area were Sternaspis scutata, Paraplionospio pinnata, and those in the mouth of the bay were Mediomastus californiensis, Nephtys polybranchia. Seasonal fluctuations and spatial difference of environments seem to have influenced to the species compositions and affected to the stability of benthic ecosystems spatial-temporally In Chonsu nay.

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Study of Characteristics of Self-Excitation in Lifted Laminar Free-Jet Propane Flames Diluted with Nitrogen (질소 희석된 프로판 자유제트 층류부상화염에 있어서 화염 자기진동 특성에 관한 연구)

  • Yoon, Sung-Hwan;Park, Jeong;Kwon, Oh-Boong;Bae, Dae-Seok
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.4
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    • pp.399-408
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    • 2010
  • The characteristics of lifted laminar propane flames diluted with nitrogen have been investigated experimentally to elucidate self-excitation and the effects of flame curvature. Flame oscillation modes are classified as follows: oscillation induced by heat loss, a combination of oscillations induced by heat loss and buoyancy, and a combination of the oscillations induced by heat loss and diffusive thermal instability. It is shown that the oscillation induced only by heat loss is not relevant to the diffusive thermal instability and hydrodynamic instability caused by buoyancy; this oscillation is observed under all lift-off flame conditions irrespective of the fuel Lewis number. These experimental evidences are displayed through the analysis of the power spectrum for the temporal variation of lift-off height. The possible mechanism of the oscillation induced by heat loss is also discussed.

An Analysis of Aerosol-Cloud Relationship Using MODIS and NCEP/NCAR Reanalysis Data around Korea (한반도 주변에서 MODIS와 NCEP/NCAR 재분석 자료를 이용한 에어로졸과 구름의 연관성 분석)

  • Kim, Yoo-Jun;Lee, Jin-Hwa;Kim, Byung-Gon
    • Journal of Korean Society for Atmospheric Environment
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    • v.27 no.2
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    • pp.152-167
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    • 2011
  • MODIS/Terra level 3 and NCEP/NCAR Reanalysis data from 2001 to 2008 have been analyzed to understand long-term aerosol and cloud optical properties, and their relationships around Korea. Interestingly, cloud fraction(CF) has the similar annual variation to aerosol optical depth (${\tau}_a$) without any temporal significant trend. Horizontal distributions of ${\tau}_a$ showed the substantial horizontal gradient from China to Korea, especially with the strong difference over the Yellow Sea, which could represent the evidence of the anthropogenic influence from China in the perspective of long-term average. Specifically the negative correlations between ${\tau}_a$ and liquid-phase cloud effective radius ($r_e$) were shown on the monthly-average basis, only in summer with significant associations over the Yellow Sea, but not in the other seasons and/or specific regions. Relationship between ${\tau}_a$ and CF for the low-level liquid-phase clouds exhibited the overall positive correlation, being consistent with cloud lifetime effect. Meanwhile static stability showed no deterministic relationships with ${\tau}_a$ as well as CF. The dependence of aerosol-cloud relationship on the meteorological conditions should be examined more in detail with the satellite remote sensing and reanalysis data.

A Study of the Characteristics of Input Boundary Conditions for the Prediction of Urban Air Flow based on Fluid Dynamics (유체 역학 기반 도시 기류장 예측을 위한 입력 경계 바람장 특성 연구)

  • Lee, Tae-Jin;Lee, Soon-Hwan;Lee, Hwawoon
    • Journal of Environmental Science International
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    • v.25 no.7
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    • pp.1017-1028
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    • 2016
  • Wind information is one of the major inputs for the prediction of urban air flow using computational fluid dynamic (CFD) models. Therefore, the numerical characteristics of the wind data formed at their mother domains should be clarified to predict the urban air flow more precisely. In this study, the formation characteristics of the wind data in the Seoul region were used as the inlet wind information for a CFD based simulation and were analyzed using numerical weather prediction models for weather research and forecasting (WRF). Because air flow over the central part of the Korean peninsula is often controlled not only by synoptic scale westerly winds but also by the westerly sea breeze induced from the Yellow Sea, the westerly wind often dominates the entire Seoul region. Although simulations of wind speed and air temperature gave results that were slightly high and low, respectively, their temporal variation patterns agreed well with the observations. In the analysis of the vertical cross section, the variation of wind speed along the western boundary of Seoul is simpler in a large domain with the highest horizontal resolution as compared to a small domain with the same resolution. A strong convergence of the sea breeze due to precise topography leads to the simplification of the wind pattern. The same tendency was shown in the average vertical profiles of the wind speed. The difference in the simulated wind pattern of two different domains is greater during the night than in the daytime because of atmospheric stability and topographically induced mesoscale forcing.

A Case Report of RED II Distraction Osteogenesis and Early Rigid Fixation by Minimal Invasive Approach Le Fort III Osteotomy in Crouzon's Disease (크루존씨 병에서 최소침습 절개법 Le Fort III 절골술을 통한 RED II 골 신연술 후 조기 고정 1례)

  • Kim, Young Seok;Lee Linton, Jina;Park, Beyoung Yun
    • Archives of Plastic Surgery
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    • v.34 no.1
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    • pp.123-127
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    • 2007
  • Purpose: Rigid external distraction(RED) is a highly effective technique for correction of maxillary hypoplasia in patients with cleft or syndromic craniosynostosis. Despite many advantages of RED, it also has the problem of relapse as the conventional advancement surgery. Bicoronal approach, that is the common approach to gain access to the craniofacial skeleton, had some morbidity, such as hair loss, sensory loss, wide scar and temporal hollowing. We present our clinical experience of RED distraction with minimal invasive approach and early rigid fixation to overcome these disadvantages. Methods: A 27-year-old female patient with Crouzon's disease underwent Le Fort III osteotomy and RED device application through the minimal invasive direct skin incisions. After the latent period of 5 days, distraction was undertaken until proper convexity and advancement were obtained. During the rigid retention period, inflammation occurred on the right cheek, and proper conservative managements were done including continuous irrigation. To maintain the stability of distraction, early rigid fixation was undertaken on the osteotomy sites through another skin incisions. Preoperative and postoperative orthodontic treatments were performed. Serial photographs and cephalometric radiographs were obtained preoperatively, after distraction and 6 months after distraction. Results: The cephalometric analysis demonstrated postoperatively significant advancement of the maxilla and improvement of facial convexity. After 6-month follow-up period, the maxilla was stable in the sagittal plane and no relapse was found. Facial scars were not noticeable and other deformity and morbidity did not occur. Conclusion: This effective and stable technique will be a good alternative for the patients who need large amount of distraction and for adult patients with severe maxillary hypoplasia or syndromic craniosynostosis.

A merging framework for improving field scale root-zone soil moisture measurement with Cosmic-ray neutron probe over Korean Peninsula

  • Nguyen, Hoang Hai;Choi, Minha
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.154-154
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    • 2019
  • Characterization of reliable field-scale root-zone soil moisture (RZSM) variability contribute to effective hydro-meterological monitoring. Although a promising cosmic-ray neutron probe (CRNP) holds the pontential for field-scale RZSM measurement, it is often restricted at deeper depths due to the non-unique sensitivity of CRNP-measured fast neutron signal to other hydrogen pools. In this study, a merging framework relied on coupling cosmic-ray soil moisture with a representative additional RZSM, was introduced to scale shallower CRNP effective depth to represent root-zone layer. We tested our proposed framework over a densely vegetated region in South Korea covering a network of one CRNP and nine in-situ point measurements. In particular, cosmic-ray soil moisture and ancillary RZSM retrieved from the most time stable location were considered as input datasets; whereas the remaining point locations were used to generate a reference RZSM product. The errors between these two input datasets and the reference were forecasted by a linear autoregressive model. A linear combination of forecasts was then employed to compute a suitable weight for merging two input products from the predicted errors. The performance of merging framework was evaluated against reference RZSM in comparison to the two original products and a commonly used exponential filter technique. The results of this study showed that merging framework outperformed other products, demonstrating its robustness in improving field-scale RZSM. Moreover, a strong relationship between the quality of input data and the performance merging framework in light of CRNP effective depth variation has been also underlined via the merging framework.

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