• Journal of the Korean Data and Information Science Society
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• v.20 no.6
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• pp.1075-1083
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• 2009

The scientific research method went through construction of hypothesis and collection of data by experiment or observation and abstracting the hypothesis based on the experience which uses the data. The statistical methodology plays an important role in this process. The method which acquires a data becomes an initial process of abstraction and a survey research using structured questionnaires is a basic tool. After the data is acquired, the high-class statistical techniques such as the regression analysis and the linear structural equation model are used to abstract a hypothesis. By the way, from time to time the concepts which have become abstractive do not help us to understand an actual phenomena, rather it is need to extract some knowledge from questions themselves. In this article, we review the well known statistical methods providing the ways of finding core questions which possibly answer a researcher wants to know. We deal with course evaluation data as an example and try to set up the strategy for improving course evaluation.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.270-277
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• 2018

The adsorption of Eosin Y by the activated carbon (WCAC) prepared from waste citrus peel was investigated by using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. Experiments were carried out as per BBD with three input parameters, the Eosin Y concentration (Conc. : 30~50 mg/L), the solution temperature (Temp. : 293~313 K), and the adsorbent dose (Dose : 0.05~0.15 g/L). Regression analysis showed a good fit of the experimental data to the second-order polynomial model with coefficients of the determination ($R^2$) value of 0.9851 and P-value (Lack of fit) of 0.342. An optimum dye uptake of 59.3 mg/g was achieved at the dye concentration of 50 mg/L, the temperature of 333 K, and the adsorbent dose of 0.1056 g. The adsorption process of Eosin Y by WCAC can be well described by the pseudo second order kinetic model. The experimental data followed the Langmuir isotherm model.

• The KIPS Transactions:PartC
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• v.14C no.3 s.113
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• pp.305-312
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• 2007

In this paper, we present a received signal strength (RSS) prediction model to timely Initiate link layer triggers for fast handoff in a wireless LAN system. Noting that the distance between a mobile terminal and an access point is not changed abruptly in a short time interval, an adaptive RSS predictor based on a stationary time series model is proposed. RSS data obtained from ns-2 simulations are used to identity the time series model and verify the predictability of the RSS data. The results suggest that an autoregressive process of order 1 (AR(1)) can be used to represent the measured RSSs in a short time interval and predict at least 1-step ahead RSS with a high confidence level.

• The Transactions of the Korea Information Processing Society
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• v.3 no.1
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• pp.211-224
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• 1996

In the research area of estimation of the software development efforts, a number of researches have been accomplished in order to control the costs and to make software more competitive. However, most of them were restricted to the functional algorithm models or the statistic models. Moreover, since they are dealing with the cases of foreign countries, the results are hard to apply directly to the domestic environment for the efficient project management because of lack of accuracy, fitness, flexibility and portability. Therefore, it is appropriate to suggest and propose a new approach supported by artificial neural network which is composed of back propagation and feel-forward algorithms to improve the exactness of the efforts estimation and to advance practical uses. In this study, the artificial neural network approach is used to model the software cost estimation and the results are compared with the revised COCOMO and the multiregression model in order to validate the superiority of the model.

• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.431-442
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• 2018

2-dimensional barcode, QR code has been used for containing various information such as image, video, map, and business cards. Currently, a smartphone is used as a QR code scanner, displaying the code and converting it to a standard URL for a website. However, QR codes are not very common in encrypted application and so have a few applications. This paper proposes a new color-code, which integrates the conventional QR code and color design, and can be effectively used in some product certification system. The proposed method exploits the fact that genuine code is produced by CMYK color model, but the counterfeit is captured by RGB color model and during this process, color information of the code is changed. This paper introduces the color matrix model to measure the distortion between genuine code and counterfeit code. By investigating the statistical characteristics of color matrix, an effective detection of print image forgeries are designed. Various experiments with color codes show that the proposed system can be effectively used in product certification systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5A
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• pp.441-450
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• 2006

Recently, with the exponential growth of the number of Internet users, IP traffic which occupies more than 90 percent of the entire Internet traffic affects significantly to the performance of networks. Therefore, the design of the self-similar traffic generator reflected the feature of IP traffic is very important to design the networks efficiently and evaluate the performance of it correctly. In this paper, we design the self-similar traffic generator using OPNET. In order to implement the self-similar characteristics, ON-OFF sources with Pateto distribution are employed and aggregated. The designed self-similarity traffic generator is evaluated and verified with R/S plot, variance time(VT) plot under the various offered loads and the number of sources. It is expected that the designed self-similar traffic generator can be put to practical use when wire or wireless networks is designed and verified as well as it can be useful to decide the specific parameter value for Internet traffic modeling.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.1
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• pp.27-35
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• 2012

In this study, the ground motion was synthesized using the finite fault model by the stochastic green function method, and the difference in the ground motions was evaluated by using various values of the source parameters. An earthquake with a moment magnitude of 6.5 was assumed for the example fault model. The distribution of the slip in the fault plane was calculated using the statistical data of the asperity area. The source parameters considered in this study were the location of the hypocenter in the fault plane and the ratio of the rupture to the shear wave velocity, the rise time, the corner frequency of the source spectrum, and a high frequency filter. The values of the parameters related to the stochastic element source model were adjusted for different tectonic regions, and the others were selected for several possible cases. The response spectra were constructed from the synthesized ground motion time history and compared with the different parameter values. The frequency range affected by each parameter and the differences of the spectral accelerations were evaluated.

• Journal of the Korea Institute of Building Construction
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• v.14 no.6
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• pp.545-550
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• 2014

The re-locatable military facilities are significant in combat zones with limited infrastructures. Military tents are particularly one of the most essential components in the battlefields, During the offensive operation. This study assesses educational effectiveness of the 4D Building Information Modeling (BIM), which is used to deliver educational information with considering re-locatable military facility construction. Furthermore, the real time for constructing temporary concentration camp was measured, By using analysis of variance associated with the educational effects of the 4D BIM. Statistically, understandability of facility construction using 4D BIM was found to be higher than the conventional educational materials with field manual.

• Journal of the Korean Data and Information Science Society
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• v.28 no.1
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• pp.153-161
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• 2017

Branching processes which is used for epidemic dispersion as stochastic process model have advantages to estimate parameters by real data. We have to estimate both mean and dispersion parameter in order to use the negative binomial distribution as an offspring distribution on branching processes. In existing studies on biology and epidemiology, it is estimated using maximum-likelihood methods. However, for most of epidemic data, it is hard to get the best precision of maximum-likelihood estimator. We suggest a Bayesian inference that have good properties of statistics for small-sample. After estimating dispersion parameter we modelled the posterior distribution for 2015 Korea MERS cases. As the result, we found that the estimated dispersion parameter is relatively stable no matter how we assume prior distribution. We also computed extinction probabilities on branching processes using estimated dispersion parameters.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.4
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• pp.37-48
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• 2010

The seismic control effect of reinforced concrete structures with low energy dissipating capacity due to stiffness degradation is investigated through nonlinear time history analysis. The primary structure is idealized as a SDOF system of modified Takeda hysteresis rule and an elasto-perfectly-plastic nonlinear spring is added to represent a hysteretic damping device. Based on statistics of the numerical analysis, equivalent linearization techniques are evaluated, and empirical equations for response prediction are proposed. As a result, estimation of the ductility demand with proposed empirical equations is more desirable than the equivalent linearization techniques. The optimal yield strengths based on empirical equations are significantly different from the optimal yield strength of elasto-perfectly-plastic systems. Also, the results indicate that the reduction effect of the ductility demand is more remarkable for smaller natural periods.