• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.7
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• pp.921-927
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• 2013

The performance estimation of a landing gear with uncertain parameters is presented. In actual use, many parameters can have certain degrees of variations that affect the energy absorbing performance. For example, the shock strut gas pressure, oil volume, tire pressure, and temperature can deviate from their nominal values. The objective function in this study is the ground reaction during touchdown, which is a function of the abovementioned parameters and time. To consider the uncertain properties, convex modeling and interval analysis are used to calculatethe objective function. The numerical results show that the ground reaction characteristics are quite different from those of the deterministic method. The peak load, which affects the efficiency and structural integrity, is increases considerably when the uncertainties are considered. Therefore, it is important to consider the uncertainties, and the proposed methodology can serve as an efficient method to estimate the effect of such uncertainties.

• Journal of Korea Water Resources Association
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• v.38 no.12 s.161
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• pp.1051-1060
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• 2005

The present study analyzes hydrologic utilization of optimal radar-derived rainfall by using semi-distributed TOPMODEL and evaluates the impacts of radar rainfall and model parametric uncertainty on a hydrologic model. Monte Carlo technique is used to produce the flow ensembles. The simulated flows from the corrected radar rainfalls with real-time bias adjustment scheme are well agreed to observed flows during 22-26 July 2003. It is shown that radar-derived rainfall is useful for simulating streamflow on a basin scale. These results are diagnose with which radar-rainfall Input and parametric uncertainty influence the character of the flow simulation uncertainty. The main conclusions for this uncertainty analysis are that the radar input uncertainty is less influent than the parametric one, and combined uncertainty with radar and Parametric input can be included the highest uncertainty on a streamflow simulation.

• Journal of Korea Technology Innovation Society
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• v.14 no.4
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• pp.761-790
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• 2011

In the knowledge-based economy, firms are increasingly exploiting their intellectual properties, especially patents. However, firms usually fail to commercialize all of their patents and some of them are not used even for strategic purposes. Therefore managing sleeping patents constitutes one important aspect of firms' overall patent strategies. This paper considers market uncertainty, technology uncertainty and strategic uncertainty as the reasons for sleeping patents. We analyze how firms' patent-related activities can reduce sleeping patent ratios. The firms' activities examined in here are patent audit, preliminary evaluation, prior art and cooperation. Noticing the prevalence of sleeping patents, this paper contributes by providing insights into how firm's activities affect the sleeping patent ratios. Insights for practitioners and policy makers have been provided from the empirical results.

• Journal of Science and Technology Studies
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• v.7 no.1
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• pp.5-31
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• 2007

In the catchup stages of technological development, the technology being pursued was well known. The fact that the technology is developable was known, and the fact that it should observe certain design is also known to developers. Therefore the technological and societal uncertainties have been relatively low. Comparatively, in the post-catchup stages of technological development, it is hard to predict if a certain technology is developable at all. And even though it is developable, in many cases the role models to which developers can refer to do not exist. This creates heavy uncertainties in both technological and societal regime. As a result, we need new strategical approaches to deal with the uncertainties that post-catchup technologies co-create. In this paper, we first define the core strategies of managing the techno-economic uncertainties as following: (1) how to deal with technological uncertainties, (2) how to acquire the justification and robustness of new technology. Then new conceptual frameworks to deal with those factors will be suggested.

• The Journal of the Korea Contents Association
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• v.13 no.2
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• pp.62-70
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• 2013

This study proposes smart-phone game applications success model based on mobile internet success model and investigates the effects of cultural propensities especially, uncertainty avoidance and power distance at the individual level. To achieve our research purposes, the study conducted survey in Korea and a total of 221 people participated in the survey. We classified user types by cultural difference as a moderating variable. User's cultural propensity classified two groups: high uncertainty avoidance and high power distance, low uncertainty avoidance and low power distance. This study results reveal that the impact of quality factors on user satisfaction have difference according to cultural propensities.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.11
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• pp.983-989
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• 2007

The bird strike simulation is a problem characterized by a high degree of uncertainty. It deals with nonlinear dynamics, complicated models of bird materials and geometry, as well as a plenty of possible boundary and initial conditions. In this complex field, uncertainty management plays an important role. This paper aims to assess the effect of input uncertainty of bird strike analysis on the impact behavior of the leading edge of the WIG(Wing in Ground Effect) craft obtained with finite element analysis using LS-DYNA 3D. The uncertainties of the bird strike simulation arise due to imprecision or lack of information, due to variability or scatter, or as a consequence of model simplification. These uncertain parameters are represented by fuzzy numbers with their membership functions quantifying an initial guess for the actual value of the model parameter. Using the transformation method as a special implementation of fuzzy arithmetic, the model can be analyzed with the intention of determining the influence of each uncertain parameter on the overall bird strike behavior.

• Journal of Korea Water Resources Association
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• v.51 no.6
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• pp.523-533
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• 2018

The objective of this study is to analyze uncertainties of ensemble-based streamflow prediction method for model parameters and input data. ESP (Ensemble Streamflow Prediction) and BAYES-ESP (Bayesian-ESP) based on ABCD rainfall-runoff model were selected as streamflow prediction method. GLUE (Generalized Likelihood Uncertainty Estimation) was applied for the analysis of parameter uncertainty. The analysis of input uncertainty was performed according to the duration of meteorological scenarios for ESP. The result showed that parameter uncertainty was much more significant than input uncertainty for the ensemble-based streamflow prediction. It also indicated that the duration of observed meteorological data was appropriate to using more than 20 years. And the BAYES-ESP was effective to reduce uncertainty of ESP method. It is concluded that this analysis is meaningful for elaborating characteristics of ESP method and error factors of ensemble-based streamflow prediction method.

• Tunnel and Underground Space
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• v.13 no.2
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• pp.87-99
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• 2003

Geostatistics is defined as the theory of modeling of regionalized variables and is an efficient and elegant methodology for estimation and uncertainty evaluation from limited spatial sample data. In this study, we have made a theoretical comparison between kriging estimation and geostatistical simulation methods. Kriging methods do not preserve the histogram of original data nor their spatial structure, and also provide only an incomplete measure of uncertainty when compared to the simulation methods. A practical procedure of geostatistical simulation is suggested in this study and the technique is demonstrated through an application, in which it was used to identify the spatial distribution of RMR as well as to evaluate the spatial uncertainty. It is concluded that the geostatistical simulation is the appropriate method to quantify the spatial uncertainty of geotechnical variables such as RMA. Therefore, the results from the simulation can be used as useful information for designer's considerations in decision-making under various geological conditions as well as the related terms of contract.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.117-127
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• 2009

This study analyzed the uncertainty of the forecasted link traffic flow, and estimated of the interval link flow using Korea Transport Data Base (KTDB) to consider those risks into the feasibility study. In the paper, the uncertainty was analyzed according to the stochastic variation of the KTDB origin-destination traffic. It was found that the uncertainty of the entire network traffic forecasts was 15.4% in average,. when the stochastic variation of the KTDB was considered. The results showed that the more congested the roads were, the bigger the uncertainty of forecasted link traffic flow were found. In particular, we estimated the variance of the forecasted traffic flow, and suggested interval estimates of the forecasted traffic flow instead of point estimates which were presented in the common feasibility studies. These results are expected to contribute the quantitative evaluation of uncertain road investment projects and to provide valuable information to the decision makers for the transport investment.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.337-344
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• 2019

The purpose of this study is to explore the uncertainty as the healing function in the poetry of Robert Frost. One of the therapeutic functions in poetry therapy is to make us look into life from a new perspective, which appears in the uncertainty of his poetry. His uncertainty is based on his peculiar poetic theory and philosophy of dualism. This paper reviews these things and deals with aspects of the uncertainty in detail through his poems. The result of this study shows that Frost conveys elements of ambiguity, illogical development and unpredictability in our society and fear, loneliness and anxiety in our daily life, and also offers realistic depictions of complex life as a therapeutic medium for overcoming these problems. So it seems that his poetry provides us with a recovery of psychic health and a possibility of healing and personal growth. Furthermore we need a practical in-depth study on the healing function of English poetry.