• Title/Summary/Keyword: assimilation

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Assimilation of Oceanographic Data into Numerical Models over the Seas around Korea

  • Kim, Seung-Bum
    • Korean Journal of Remote Sensing
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    • v.17 no.4
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    • pp.345-357
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    • 2001
  • This review provides a summary of data assimilation applied to the seas around Korea. Currently the worldwide efforts are devoted to applying advanced assimilation to realistic cases, thanks to improvements in mathematical foundations of assimilation methods and the computing capabilities, and also to the availability of extensive observational data such as from satellites. Over the seas around Korea, however, the latest developments in the advanced assimilation methods have yet to be applied. Thus it would be timely to review the progress in data assimilation over the seas. Firstly, the definition and necessity of data assimilation are described, continued by a brief summary of major assimilation methods. Then a review of past research on the ocean data assimilation in the regional seas around Korea is given and future trends are considered. Special consideration is given to the assimilation of remotely-sensed data.

Determinants of E-Government Assimilation in Indonesia: An Empirical Investigation Using a TOE Framework

  • Pudjianto, Boni;Zo, Hangjung;Ciganek, Andrew P.;Rho, Jae-Jeung
    • Asia pacific journal of information systems
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    • v.21 no.1
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    • pp.49-80
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    • 2011
  • E-government needs to be successfully implemented and assimilated into organizations to take advantage of its potential values and benefits for organizations. This study examines factors for e-government assimilation in Indonesia and employs the TOE (Technology-Organization-Environment) framework to develop a theoretical model to explain e-government assimilation. It also investigates how organizational type (central vs. local) plays a role in the assimilation of e-government. One hundred eighteen respondents from the central and local governments in Indonesia participated in the survey and an in-depth analysis based on partial least squares (PLS) was carried out. The results show that ICT infrastructure has the strongest significant relationship with e-government assimilation, Top management support, regulatory environment, ICT expertise, and competitive environment are also significant factors to explain e-government assimilation in Indonesia. Central and local governments Significantly differ in terms of e-government assimilation, so organizational type can be a moderator in the process of e-government assimilation. These findings present the efficacy of the proposed model for analyzing e-government assimilation and contribute additional insights for academia as well as practitioners and policy makers.

Comparison of Acid and Bile Tolerances, Cholesterol Assimilation, and CLA Production in Probiotic Lactobacillus acidophilus Strains

  • Oh, Se-Jong;Chai, Chang-Hun;Kim, Sae-Hun;Kim, Young-Jun;Kim, Hyung-S.;Worobo, Randy W.
    • Food Science of Animal Resources
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    • v.32 no.4
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    • pp.409-413
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    • 2012
  • This study aimed to compare the probiotic characteristics of twelve strains of Lactobacillus acidophilus including cholesterol assimilation and conjugated linoleic acid (CLA) production. Cholesterol assimilation exhibited some variation among L. acidophilus strains, which could be classified into three groups based on their assimilation levels (p<0.05). The high cholesterol assimilation group exhibited a significantly higher tolerance to 0.3 and 0.5% bile acid than the low cholesterol assimilation group (p<0.05). Cholesterol assimilation showed positive correlation with 0.5% bile tolerance, and a negative correlation with acid tolerance (p<0.01). Glycocholate deconjugation activity showed no relationship with cholesterol assimilation, whereas taurocholate deconjugation activity was shown to have negative correlation with cholesterol assimilation (p<0.05). CLA production by L. acidophilus strains exhibited a wide variation, ranging from 2.69 to 5.04 mg/g fat. CLA production of L. acidophilus GP1B was the highest among the tested strains, but there was no evidence for differences in CLA production in strain specificity. Based on these results, the cholesterol assimilation of L. acidophilus strains may not be related to deconjugation activity, but may in-fact be attributed to their bile-tolerance.

The Effect of the Strategical Factors Towards the Assimilation of the Web-Technology (웹기술의 흡수에 전략적 요인이 미치는 영향)

  • Son Dal-Ho
    • Korean Management Science Review
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    • v.21 no.2
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    • pp.27-42
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    • 2004
  • Assimilation is defined as the extent to which the use of a technology diffuses across organizational work processes and becomes routinized in the activities associated with those processes. Assimilation is an important construct in the casual chain of influence from the organizational adoption of an information technology to the evidence of its impacts on business performance. Given a wide range of experiences with the effective assimilation of Web technologies. there is a need to discover how firms can institutionally encourage the managerial activities that will result in greater levels of technology assimilation. This study analyzes or shows which organizational and strategical factors like management belief. management participation. strategic investment rationale and coordination mechanism have impact on the assimilation of web technologies. Moreover. this research is tried under the different types of firms. manufacturing and service firms. The result shows that the management belief among the determinants had a significant effect on the assimilation of web technology. However. the result would be generalized with the inclusion of the psychological factors to the current model.

A Suggestion for Data Assimilation Method of Hydrometeor Types Estimated from the Polarimetric Radar Observation

  • Yamaguchi, Kosei;Nakakita, Eiichi;Sumida, Yasuhiko
    • Proceedings of the Korea Water Resources Association Conference
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    • 2009.05a
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    • pp.2161-2166
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    • 2009
  • It is important for 0-6 hour nowcasting to provide for a high-quality initial condition in a meso-scale atmospheric model by a data assimilation of several observation data. The polarimetric radar data is expected to be assimilated into the forecast model, because the radar has a possibility of measurements of the types, the shapes, and the size distributions of hydrometeors. In this paper, an impact on rainfall prediction of the data assimilation of hydrometeor types (i.e. raindrop, graupel, snowflake, etc.) is evaluated. The observed information of hydrometeor types is estimated using the fuzzy logic algorism. As an implementation, the cloud-resolving nonhydrostatic atmospheric model, CReSS, which has detail microphysical processes, is employed as a forecast model. The local ensemble transform Kalman filter, LETKF, is used as a data assimilation method, which uses an ensemble of short-term forecasts to estimate the flowdependent background error covariance required in data assimilation. A heavy rainfall event occurred in Okinawa in 2008 is chosen as an application. As a result, the rainfall prediction accuracy in the assimilation case of both hydrometeor types and the Doppler velocity and the radar echo is improved by a comparison of the no assimilation case. The effects on rainfall prediction of the assimilation of hydrometeor types appear in longer prediction lead time compared with the effects of the assimilation of radar echo only.

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Development of the Three-Dimensional Variational Data Assimilation System for the Republic of Korea Air Force Operational Numerical Weather Prediction System (공군 현업 수치예보를 위한 삼차원 변분 자료동화 체계 개발 연구)

  • Noh, Kyoungjo;Kim, Hyun Mee;Kim, Dae-Hui
    • Journal of the Korea Institute of Military Science and Technology
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    • v.21 no.3
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    • pp.403-412
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    • 2018
  • In this study, a three-dimensional variational(3DVAR) data assimilation system was developed for the operational numerical weather prediction(NWP) system at the Republic of Korea Air Force Weather Group. The Air Force NWP system utilizes the Weather Research and Forecasting(WRF) meso-scale regional model to provide weather information for the military service. Thus, the data assimilation system was developed based on the WRF model. Experiments were conducted to identify the nested model domain to assimilate observations and the period appropriate in estimating the background error covariance(BEC) in 3DVAR. The assimilation of observations in domain 2 is beneficial to improve 24-h forecasts in domain 3. The 24-h forecast performance does not change much depending on the estimation period of the BEC in 3DVAR. The results of this study provide a basis to establish the operational data assimilation system for the Republic of Korea Air Force Weather Group.

Analysis of the Relation between Spatial Resolution of Initial Data and Satellite Data Assimilation for the Evaluation of Wind Resources in the Korean Peninsula (한반도 풍력자원 평가를 위한 초기 공간해상도와 위성자료 동화의 관계 분석)

  • Lee, Soon-Hwan;Lee, Hwa-Woon;Kim, Dong-Hyuk;Kim, Hyeon-Gu
    • Journal of Korean Society for Atmospheric Environment
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    • v.23 no.6
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    • pp.653-665
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    • 2007
  • Several numerical experiments were carried out to clarify the influence of satellite data assimilation with various spatial resolution on mesoscale meteorological wind and temperature field. Satellite data used in this study is QuikSCAT launched on ADEOS II. QuikSCAT data is reasonable and faithful sea wind data, which have been verified through many observational studies. And numerical model in the study is MM5 developed by NCAR. Difference of wind pattern with and without satellite data assimilation appeared clearly, especially wind speed dramatically reduced on East Sea, when satellite data assimilation worked. And sea breeze is stronger in numerical experiments with RDAPS and satellite data assimilation than that with CDAS and data assimilation. This caused the lower estimated surface temperature in CDAS used cases. Therefore the influence of satellite data assimilation acts differently according to initial data quality. And it is necessary to make attention careful to handle the initial data for numerical simulations.

Coordinations of Articulators in Korean Place Assimilation

  • Son, Min-Jung
    • Phonetics and Speech Sciences
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    • v.3 no.2
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    • pp.29-35
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    • 2011
  • This paper examines several articulatory properties of /k/, known as a trigger of place assimilation as well as the object of post-obstruent tensing (/tk/), in comparison to non-assimilating controls (/kk/ and /kt/). Using EMMA, tongue body articulation in the place assimilation context robustly shows greater spatio-temporal articulation and lower jaw position. Results showed several characteristics. Firstly, constriction duration of the tongue body gesture in C2 of the assimilation context (/tk/) was longer than non-assimilating controls (/kk/ and /kt/). Secondly, constriction maxima also demonstrated greater constriction in the /tk/ sequences than in the control /kk/, but similar values with the control /kt/. In particular, results showed a significant relationship between the two variables - the longer the constriction duration, the greater the constriction degree. Lastly, jaw height was lower for the assimilating context /tk/, intermediate for the control /kk/, and higher for the control /kt/. Results suggest that speakers have lexical knowledge of place assimilation, producing a greater tongue body gesture in the spatio-temporal domains with lower jaw height as an indication of anticipating reduction of C1 in /tk/ sequences.

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The Determinants of IT Assimilation and Its Effect on Organizational Performance : An Innovation Diffusion Theory Perspective (정보기술동화의 결정요인 및 기업성과에 미치는 영향 : 혁신확산이론의 관점)

  • Kwahk, Kee-Young;Im, So-Yeon
    • Journal of the Korean Operations Research and Management Science Society
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    • v.33 no.1
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    • pp.149-168
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    • 2008
  • Many organizations have introduced information technology (IT) as an innovation to gain competitive advantages as business environments have become increasingly complex and rapidly changing. Despite the large investment of IT, there have been mixed results about whether IT creates business values. Considering that IT assimilation may play an important role in explaining IT productivity paradox, this study examines the formation of IT assimilation and its effect on the organizational performance. To do so, this study suggests a research model based on Innovation Diffusion Theory by incorporating organization system, communication channel, change acceptability, and innovation factors, and then attempts to empirically explore the role of IT assimilation for enhanced organizational performance using data collected at the organizational level. Structural equation analysis using AMOS provides significant support for part of proposed relationships. Specifically, we have found encouraging results on the role of IT assimilation by identifying its mediating effect on the organizational performance. Theoretical and practical implications of the findings are discussed accordingly.

Numerical Study on Surface Data Assimilation for Estimation of Air Quality in Complex Terrain (복잡 지형의 대기질 예측을 위한 지상자료동화의 효용성에 관한 수치연구)

  • 이순환;김헌숙;이화운
    • Journal of Korean Society for Atmospheric Environment
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    • v.20 no.4
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    • pp.523-537
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    • 2004
  • In order to raise the accuracy of meteorological data, several numerical experiments about the usefulness of data assimilation to prediction of air pollution was carried out. Used data for data assimilation are surface meteorological components observed by Automatical Weather System with high spatial density. The usage of surface data assimilation gives changes of temperature and wind fields and the change caused by the influence of land-use on meterological simulation is more sensitive at night than noon. The data quality in assimilation it also one of the important factors to predict the meteorological field precisely and through the static IOA (Index of Agreement), simulated meteorological components with selected limited surface data assimilation are agree well with observations.