• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1D
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• pp.43-50
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• 2011

The monitoring system for link travel speed using taxi probe is one of key sub-systems of ITS. Link travel speed collected by taxi probe has been widely employed for both monitoring the traffic states of urban road network and providing real-time travel time information. When sample size of taxi probe is small and link travel time is longer than a length of time interval to collect travel speed data, and in turn the missing state is inevitable. Under this missing state, link travel speed data is real-timely not collected. This missing state changes from single to multiple time intervals. Existing single interval prediction techniques can not generate multiple future states. For this reason, it is necessary to replace multiple missing states with the estimations generated by multi-interval prediction method. In this study, a multi-interval prediction method to generate the speed estimations of single and multiple future time step is introduced overcoming the shortcomings of short-term techniques. The model is developed based on Non-Parametric Regression (NPR), and outperformed single-interval prediction methods in terms of prediction accuracy in spite of multi-interval prediction scheme.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.7
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• pp.4141-4149
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• 2013

Background: Mammography is considered the gold standard of breast cancer mass screening and many countries have implemented this as an established breast cancer screening strategy. However, although the incidence of breast cancer and racial characteristics are different between Western and Asian countries, many Asian countries adopted mammography for mass screening. Therefore, the objective of this research was to determine whether mammography mass screening is cost-effective for both Western and Asian countries. Materials and Methods: A systematic review was performed of 17 national mammography cost-effectiveness data sets. Per capita gross domestic product (GDP), breast cancer incidence rate, and the most optimal cost-effectiveness results [cost per life year saved (LYS)] of a mammography screening strategy for each data set were extracted. The CE/per capita GDP ratio is used to compare the cost-effectiveness of mammography by countries. Non-parametric regression was used to find a cut-off point which indicated the breast cancer incidence rate boundary line determining whether mammography screening is cost-effective or not. Results: We found that the cost-effective cut-off point of breast cancer incidence rate was 45.04; it exactly divided countries into Western and Asian countries (p<0.0014). Conclusions: Mammography screening is cost-effective in most of Western countries, but not in Asian countries. The reason for this result may be the issues of incidence rate or racial characteristics, such as dense breast tissue. The results indicate that mammography screening should be adopted prudently in Asian countries and other countries with low incidence rates.

• Journal of Acupuncture Research
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• v.20 no.1
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• pp.144-158
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• 2003

This study was carried out to investigate what kinds of statistical techniques have been used to analyze data from oriental medicine research, For study, 551 original articles which used statistical techniques in their data analysis were selected form the articles published in The journal of Korean Acupuncture & Moxibustion Society(JKAMS) between 1984 to 2002. among them, 122 articles used descriptive statistics while 429 articles used inferential statistics for data analysis. For that 429 articles, t-test (189 articles), analysis fo variance (111 articles), chi-square test (14 articles), correlation (10 articles), regression analysis (4 articles), factor analysis(5 articles), or nonparametric test (23 articles) were chose to analyze the data. Nonparametric approach has substantial power in case data do not meet the assumption of normality. This method is not only easy to use ut also provides measures of the statistical variation of nominal and ordinal scale. This study shows that more and more recent papers use nonparametric test compared to the old articles. nine different statistical software or packages (SAS, SPSS, Statview, Minitab, Sigma plot, ISP, Graphpad prism, Excel, Access) have been used in the articles published JKMAS. High level statistical techniques such as SAS, SPSS, and Statview are user friendly and used most for acupuncture and Moxibustion research. Including tables and plots in an article facilitates understanding family process data from a descriptive standpoint, minimized erroneous statistical conclusions, and clarifies theoretically important relationships among variables. Table and plots have been used 500 and 233 articles, respectively. A computer procedure is proposed and illustrated with statistical packages using SAS, SPSS, Statview and ISP.

• Journal of Korean Society of Steel Construction
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• v.21 no.6
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• pp.609-618
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• 2009

This paper proposes a versatile formula which can be used to evaluate the fire resistant time of steel beams under various design conditions. Towards this end, the key parameters which affect the fire performance of steel beams were first determined through thermo-mechanical considerations, and classified into two groups: structural parameters and thermal parameters. Then the degree of influence of each parameter on the fire performance was investigated through a fully coupled thermo-mechanical analysis up to the occurrence of run-away deflection. The accuracy of the numerical model used was verified using an available full-scale fire test before conducting an extensive parametric analysis. Multiple linear regression analysis was performed to obtain the formula which can be used to predict the fire resistance time of steel beams under various design conditions. The statistical analysis showed that the proposed formula is very robust. The application of the formula in practical fire design under the current code was illustrated in detail. The economy and other advantages of the proposed formula were clearly shown.

• Journal of the Korean Data and Information Science Society
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• v.21 no.6
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• pp.1171-1180
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• 2010

It is well known that the asymptotic convergence rates of nonparametric regression estimator gets worse as the dimension of covariates gets larger. One possible way to overcome this problem is reducing the dimension of covariates by using single index models. Two coefficient estimation methods in single index models are introduced. One is semiparametric least square estimation method, which tries to find approximate solution by using iterative computation. The other one is weighted average derivative estimation method, which is non-iterative method. Both of these methods offer the parametric convergence rate to normal distribution. However, practical comparison of these two methods has not been done yet. In this article, we compare these methods by examining the variances of estimators in various models.

• Geotechnical Engineering
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• v.13 no.1
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• pp.75-84
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• 1997

This paper presents a bearing capacity determination method for spread footings subjected to vertical central loading and located above underground cavities. For the development of the method, a parametric study on bearing capacity of a spread footing located above an underground cavity was performed by using a threetimensional elasto-plastic finite element computer program. From the results of the finite element analysis, bearing capacity values for the conditions analyzed were determined and used as a data base from which semiempirical equation to for the bearing capacity determination method were formulated by means of a regression analysis. The effectiveness of this method was illustrated by comparing the bearing capacity values computed from this method with those of available model footing tests as well as finite element analysis data. It was concluded that the method presented in this paper can be effectively used for practical applications at least within the conditions investigated.

• Magazine of the Korea Concrete Institute
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• v.10 no.4
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• pp.135-143
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• 1998

The wheel load distribution width for lane load is not specified in current Korea bridge design code(KD code), not like in current AASHTO and AASHTO LRFD specifications which specity it as twice of wheel load distribution width for wheel load. In this study, the wheel load distribution width in continuous reinforced concrete slab bridge is investigated. The major variables affecting the wheel load distribution of a reinforced concrete continuous slab bridge are the span length, bridge width, existence edge beam and boundary condition. From a series of comprehensive parametric study on each variable, the formula for wheel load distribution in continuous reinforced concrete slab bridge is proposed from the nonlinear regression analysis of finite element analysis results. The proposed formulas can be used efficiently in the accurate design of continuous reinforced concrete slab bridges.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.8
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• pp.561-570
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• 2004

In this paper, new architectures and comprehensive design methodologies of Genetic Algorithms(GAs) based Genetically optimized Neurofuzzy Networks(GoNFN) are introduced, and a series of numeric experiments are carried out. The proposed GoNFN is based on the rule-based Neurofuzzy Networks(NFN) with the extended structure of the premise and the consequence parts of fuzzy rules being formed within the networks. The premise part of the fuzzy rules are designed by using space partitioning in terms of fuzzy sets defined in individual variables. In the consequence part of the fuzzy rules, three different forms of the regression polynomials such as constant, linear and quadratic are taken into consideration. The structure and parameters of the proposed GoNFN are optimized by GAs. GAs being a global optimization technique determines optimal parameters in a vast search space. But it cannot effectively avoid a large amount of time-consuming iteration because GAs finds optimal parameters by using a given space. To alleviate the problems, the dynamic search-based GAs is introduced to lead to rapidly optimal convergence over a limited region or a boundary condition. In a nutshell, the objective of this study is to develop a general design methodology o GAs-based GoNFN modeling, come up a logic-based structure of such model and propose a comprehensive evolutionary development environment in which the optimization of the model can be efficiently carried out both at the structural as well as parametric level for overall optimization by utilizing the separate or consecutive tuning technology. To evaluate the performance of the proposed GoNFN, the models are experimented with the use of several representative numerical examples.

• Steel and Composite Structures
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• v.8 no.5
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• pp.403-421
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• 2008

The design provisions for semi-rigid steel frames have been incorporated in codes of practice for steel structures. In order to do the same, it is necessary to know the experimental moment-relative rotation (M-${\theta}_r$) behaviour of beam-to-column connections. In spite of numerous publications and collection of several connection databases, there is no unified approach for the semi-rigid design of steel frames. Amongst the many connection models available, the Frye-Morris polynomial model, with its limitations reported in the literature, is simple to adopt at least for the linear design space. However this model requires more number of connection tests and regression analyses to make it a realistic prediction model. In this paper, 3D nonlinear finite element (FE) analysis of beam-column connection specimens, carried out using ABAQUS software, for evaluating the M-${\theta}_r$ behaviour of semi-rigid top and seat-angle (TSA) bolted connections are described. The finite element model is validated against experimental behaviour of the same connection with regard to their moment-rotation behaviour, stress distribution and mode of failure of the connections. The calibrated FE model is used to evaluate the performance of the Frye-Morris polynomial model. The results of the numerical parametric studies carried out using the validated FE model have been used in proposing modifications to the Frye-Morris model for TSA connection in terms of the powers of the size parameters.

• Journal of Wetlands Research
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• v.20 no.3
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• pp.201-209
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• 2018

In this study, the water quality index was calculated using the water quality monitoring data of the major tributaries of the Nakdong River and long-term trend analysis was performed to identify the tributaries requiring priority management. We used a Real-Time Water Quality Index method implemented by the Ministry of Environment. Linear regression as a parametric method and Mann-Kendall Test and Sen Slope Test as a nonparametric method were applied for the trend analysis. The water quality index of major tributaries except for Migeon2 and Seokyo2 was in the range below Fair grade and there were no significant trends for the rest of the sites except Bukan, Chennae, Hogye, Yongdeok. Therefore, in order to improve the water quality of the main stream, management of the tributaries should be preceded.