• Title/Summary/Keyword: Data Assimilation

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Some articulatory reflexes observed in intervocalic consonantal sequences: Evidence from Korean place assimilation

  • Son, Minjung
    • Phonetics and Speech Sciences
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    • v.12 no.2
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    • pp.17-27
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    • 2020
  • This paper examines kinematic characteristics of /pk/ clusters, as compared to /kk/ and /pp/ with varying vowel contexts and speech rate. The results of EMMA data from eight Seoul-Korean speakers indicate as follows. Firstly, comparing /pk/ to /pp/ sequences, lips closing movement was faster and spatially greater in the /a/-to-/a/ context while temporally longer in the /i/-to-/i/ context. It was smaller in spatial displacement and shorter in temporal duration in /pk/ sequences. Peak velocity did not vary. Secondly, comparing /pk/ with /pp/ and /kk/ controls, lip aperture was less constricted in the /a/-to-/a/ context than /i/-to-/i/, but the maximum contact between the upper and lower lips was invariant across different vocalic contexts within /pk/ sequences (/apka/=/ipki/). Categorical reduction of C1 in /pk/ sequences fell in with the low-vowel and fast-rate conditions with across-/within-speaker variability. Gradient reduction of C1 was observed in all C1C2 types, being more frequent in fast rate. Lastly, the jaw articulator was a stable indicator of rate effects. The implication of the current study is that gestural reduction occurs with categorical reduction and general spatiotemporal weakening in the assimilating contexts, while quantitative properties of gestures may be a reason for gradient reduction, not necessarily confined to place assimilation.

A Monitoring System of Ensemble Forecast Sensitivity to Observation Based on the LETKF Framework Implemented to a Global NWP Model (앙상블 기반 관측 자료에 따른 예측 민감도 모니터링 시스템 구축 및 평가)

  • Lee, Youngsu;Shin, Seoleun;Kim, Junghan
    • Atmosphere
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    • v.30 no.2
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    • pp.103-113
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    • 2020
  • In this study, we analyzed and developed the monitoring system in order to confirm the effect of observations on forecast sensitivity on ensemble-based data assimilation. For this purpose, we developed the Ensemble Forecast Sensitivity to observation (EFSO) monitoring system based on Local Ensemble Transform Kalman Filter (LETKF) system coupled with Korean Integrated Model (KIM). We calculated 24 h error variance of each of observations and then classified as beneficial or detrimental effects. In details, the relative rankings were according to their magnitude and analyzed the forecast sensitivity by region for north, south hemisphere and tropics. We performed cycle experiment in order to confirm the EFSO result whether reliable or not. According to the evaluation of the EFSO monitoring, GPSRO was classified as detrimental observation during the specified period and reanalyzed by data-denial experiment. Data-denial experiment means that we detect detrimental observation using the EFSO and then repeat the analysis and forecast without using the detrimental observations. The accuracy of forecast in the denial of detrimental GPSRO observation is better than that in the default experiment using all of the GPSRO observation. It means that forecast skill score can be improved by not assimilating observation classified as detrimental one by the EFSO monitoring system.

Molybdate Alters Sulfate Assimilation and Induces Oxidative Stress in White Clover (Trifolium repens L.)

  • Zhang, Qian;Lee, Bok-Rye;Park, Sang-Hyun;Jeong, Gi-Ok;Kim, Tae-Hwan
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.33 no.3
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    • pp.153-158
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    • 2013
  • Molybdenum (Mo) in rhizosphere influences sulfate assimilation as well as a number of other physiological aspects. In this study, the activity of key enzymes in sulfate assimilatory pathways, such as ATP sulfurylase (ATPs), adenosine 5'-phosphosulphate reductase (APR), as well as the responses of reactive oxygen species (ROS), were analyzed to elucidate the metabolic and physiological effects of external Mo supply to detached leaves of Trifolium repens L. Mo supply with a range from 1 mM to 40 mM depressed the activity of ATPs throughout the entire time course. In the leaves exposed to 1 mM Mo, a continuous decrease in the activity of ATPs was confirmed by Native-PAGE. The APR activity was also declined by Mo treatment. The accumulation of $H_2O_2$ and ${O_2}^{{\cdot}-}$ were not significant up to 10 mM Mo, whereas a remarked accumulation was detected under 40 mM Mo supply. The data suggest that an external supply of Mo has an inhibitory effect on sulfate assimilation, and induces oxidative stress only at an extremely high concentration.

Dynamic Thermal Rating of Overhead Transmission Lines Based on GRAPES Numerical Weather Forecast

  • Yan, Hongbo;Wang, Yanling;Zhou, Xiaofeng;Liang, Likai;Yin, Zhijun;Wang, Wei
    • Journal of Information Processing Systems
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    • v.15 no.4
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    • pp.724-736
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    • 2019
  • Dynamic thermal rating technology can effectively improve the thermal load capacity of transmission lines. However, its availability is limited by the quantity and high cost of the hardware facilities. This paper proposes a new dynamic thermal rating technology based on global/regional assimilation and prediction system (GRAPES) and geographic information system (GIS). The paper will also explore the method of obtaining any point meteorological data along the transmission line by using GRAPES and GIS, and provide the strategy of extracting and decoding meteorological data. In this paper, the accuracy of numerical weather prediction was verified from the perspective of time and space. Also, the 750-kV transmission line in Shaanxi Province is considered as an example to analyze. The results of the study indicate that dynamic thermal rating based on GRAPES and GIS can fully excavate the line power potential without additional cost on hardware, which saves a lot of investment.

Data Assimilation Techniques Applied to Estimate the Dispersion of the Pollutant in the Atmosphere (자료동화기술을 이용한 대기중 오염물질 확산평가)

  • 한문희;정효준;김은한;서경석;황원태;이선미
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2004.06a
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    • pp.368-376
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    • 2004
  • The estimation of the diffusion coefficients of the Gaussian plume model and the release rate by assimilation of tracer-gas measurements on Younggwang site was tested. Diffusion coefficients were modified by linear programming of both the measurements and the simulated using the Gaussian plume model. The application of the modified diffusion coefficients improved the prediction ability of the Gaussian plume model on both 3 km and 8 km arc lines. And, the release rate of tracer gas was estimated using least squares method. The optimal source rate was estimated by minimizing the errors between the measured concentrations and the computed ones by the Gaussian plume model. The obtained release rate showed a good agreement with the real release rate of the Younggwang experiment in 24%.

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The Effect of Individual's on Absorptive Capacity on Process and Product Innovation (개인의 흡수 역량이 프로세스 및 제품 혁신에 미치는 영향에 대한 연구)

  • Jang, Jae-Seung;Lee, Junyeong;Kwak, Chanhee;Lee, Heeseok
    • Knowledge Management Research
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    • v.17 no.1
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    • pp.135-154
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    • 2016
  • Absorptive capacity has been increasingly thought of as a potential source of innovation. From the knowledge management perspective, absorptive capacity is composed of a set of activities dealing with acquisition, assimilation, transformation, and exploitation of external and internal knowledge. This study investigates what relationship the absorptive capacity of individuals who have technical knowledge in the organization has with process innovation and product innovation. Mobile based survey was conducted from the employees working for the largest electronics manufacturer in Korea. The analyzed data was based on 156 responses from 199 participants. The analysis result shows that four phases of absorptive capacity such as acquisition, assimilation, transformation and exploitation have different effects on process innovation and product innovation, respectively. Specifically, transformation is found to be most critical in leading to innovation.

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Gradient Reduction of $C_1$ in /pk/ Sequences

  • Son, Min-Jung
    • Speech Sciences
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    • v.15 no.4
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    • pp.43-60
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    • 2008
  • Instrumental studies (e.g., aerodynamic, EPG, and EMMA) have shown that the first of two stops in sequence can be articulatorily reduced in time and space sometimes; either gradient or categorical. The current EMMA study aims to examine possible factors_linguistic (e.g., speech rate, word boundary, and prosodic boundary) and paralinguistic (e.g., natural context and repetition)_to induce gradient reduction of $C_1$ in /pk/ cluster sequences. EMMA data are collected from five Seoul-Korean speakers. The results show that gradient reduction of lip aperture seldom occurs, being quite restricted both in speaker frequency and in token frequency. The results also suggest that the place assimilation is not a lexical process, implying that speakers have not fully developed this process to be phonologized in the abstract level.

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Development of Meso-scale Short Range NWP System for the Cheju Regional Meteorological Office, Korea (제주 지역에 적합한 중규모 단시간 예측 시스템의 개발)

  • Kim, Yong-Sang;Choi, Jun-Tae;Lee, Yong-Hee;Oh, Jai-Ho
    • Journal of the Korean earth science society
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    • v.22 no.3
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    • pp.186-194
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    • 2001
  • The operational meso-scale short range NWP system was developed for Cheju Regional Meteorological Office located at Cheju island, Korea. The Central Meteorological Service Center, KMA has reported the information on numerical weather prediction every 12 hours. But this information is not enough to determine the detail forecast for the regional meteorological office because the terrain of the Korean peninsula is very complex and the resolution of the numerical model provided by KMA headquarter is too coarse to resolve the local severe weather system such as heavy rainfall. LAPS and MM5 models were chosen for three-dimentional data assimilation and numerical weather prediction tools respectively. LAPS was designed to provide the initial data to all regional numerical prediction models including MM5. Synoptic observational data from GTS, satellite brightness temperature data from GMS-5 and the composite reflectivity data from 5 radar sites were used in the LAPS data assimilation for producing the initial data. MM5 was performed on PC-cluster based on 16 pentium CPUs which was one of the cheapest distributed parallel computer in these days. We named this system as Halla Short Range Prediction System (HSRPS). HSRPS was verified by heavy rainfall case in July 9, 1999, it showed that HSRPS well resolved local severe weather which was not simulated by 30 km MM5/KMA. Especially, the structure of rainfall amount was very close to the corresponding observation. HSRPS will be operating every 6 hours in the Cheju Regional Meteorological Office from April 2000.

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