• Journal of the Korea institute for structural maintenance and inspection
• /
• v.6 no.3
• /
• pp.167-175
• /
• 2002

In this paper, an analytical model is proposed for analyzing the hysteretic behavior of RC beam with relocated plastic hinge region under load reversals. The plastic hinge is modeled not to be concentrated on a point but to be distributed on a finite size in beam. This is based on the assumption that the plastic hinge is formed over a certain region, in which the curvature varies. Tangential matrix is reformed using stiffness coefficients including variales such as the length and location of plastic hinge region. In order to construct the hysteretic rule of hinge, modified Takeda rule is also proposed on the base of regression analysis for the previous test results. Previous specimens are analyzed using the proposed model and the result is compared with test result. On the result of the comparison, it was shown that the hysteretic behavior of beams with different location of plastic hinge region could be prediced using the proposed analytical process.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.30 no.1
• /
• pp.50-62
• /
• 1988

This study refers to the development of a hydrologic model simulating daily inflow and release rates for irrigation reservoirs. A daily - based model is needed for adequate operation of an irrigation reservoir sufficing the water demand for paddy fields which is closely related to meteorological conditions. Inflow rates to a reservoir need to be accurately described, which may be simulated using a hydrologic model from daily rainfall data. And the objective of this paper is to develop, test, and apply a hydrologic model for daily runoff simmulation. A well - known tank model was selected and modified to simulate daily inflow rates. The model parameters were calibrated using observed runoff data from twelve watersheds, Relationships between the parameters and the watershed characteristics were derived by a multiple regression analysis. The simulation results were in agreement with the data. The inflow model was found to simulate low flow conditions more accurately than high flow conditions, which may be adequate for water resources utilization.

• The Journal of Engineering Geology
• /
• v.29 no.4
• /
• pp.417-425
• /
• 2019

Agricultural groundwater use accounts for 51.8% of total groundwater use, so accurate estimation of groundwater use is important for efficient groundwater management. The purpose of this study is to develop a method for estimating the groundwater use of agricultural (rice farming and dry-field farming) wells using regression tree model based on the measured data of 370 wells. Three input variables of the model were evaluated as being significant: well depth, pipe diameter, and pump capacity, and the importance of each variable was 75% for well depth, 17% for pipe diameter, and 8% for pumping capacity. The daily usage of agricultural (rice farming and dry-field farming) wells by the regression tree model was estimated to be very similar to the actual usage, compared to the previous estimation method proposed by the Ministry of Construction and Transportation. In the future, it is expected that the reliability of the usage statistics will be improved if additional observed data is secured and this classification method is modified.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.9
• /
• pp.1605-1614
• /
• 1992

The effects of % overload (% O.L), baseline stress intensity factor range (.DELTA. $K_{b}$) and dimension-less crack depth (a/W) are examined for the retardation behaviors after a single overload and high-low block loads in 7075-T73 aluminum alloy. And wheeler model, which is one of the fatigue life prediction models, is modified to predict retardation life using these test results. The retardation cycles( $N_{d}$) increased with a decrease in a/W and an increase in % O.L. and (.DELTA. $K_{b}$) These effects are more severe after high-low block loads than single overload. In the case of single overload, the main mechanisms of the retardation are the crack closure and the relaxation of K due to crack branching. But in the case of high-low block loads, that of the main mechanism is the crack closure caused by the accumulated compressive residual stree at the crack tip, which is related with the contact of fracture surfaces. Test results were multiple regression analyzed and got regressed shaping correction factors, (n)$_{REG}$, as function of %O.L., a/W and (.DELTA. $K_{b}$) Wheeler model is modified by using these (n)$_{REG}$. The number of delay cycles calculated by modified Wheeler model were in good agreement with the test results of this study.y.udy.y.y.y.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.6B
• /
• pp.399-406
• /
• 2012

The objective of this research is to develop greenhouse gas generation models and estimation method of their parameters for solid waste landfills. Two models obtained by differentiating the Modified Gompertz and Logistic models were employed to evaluate two parameters of a first-order decay model, methane generation potential ($L_0$) and methane generation rate constant (k). The parameters were determined by the statistical comparison of predicted gas generation rate data using the two models and actual landfill gas collection data. The values of r-square obtained from regression analysis between two data showed that one model by differentiating the Modified Gompetz was 0.92 and the other model by differentiating the Logistic was 0.94. From this result, the estimation methods showed that $L_0$ and k values can be determined by regression analysis if landfill gas collection data are available. Also, new models based on two models obtained by differentiating the Modified Gompertz and Logistic models were developed to predict greenhouse gas generation from solid waste landfills that actual landfill generation data could not be available. They showed better prediction than LandGEM model. Frequency distribution of the ratio of Qcs (LFG collection system) to Q (prediction value) was used to evaluate the accuracy of the models. The new models showed higher accuracy than LandGEM model. Thus, it is concluded that the models developed in this research are suitable for the prediction of greenhouse gas generation from solid waste landfills.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.56 no.4
• /
• pp.374-383
• /
• 2020

At ship design stage, the maneuverability is generally estimated based on the empirical formula or the computational fluid dynamic (CFD), which is one of the numerical simulation methods. Using the hydrodynamic derivatives derived through these methods can quantitatively estimate the maneuverability of target vessels and evaluate indirect maneuverability. Nevertheless, research on estimating maneuverability is insufficient for ships not subject to IMO maneuverability standard, especially fishing vessels, and even at the design stage, the empirical formula developed for merchant ships is applied without modification. An estimation error may occur due to the empirical formula derived from the regression analysis results of a model test if the empirical formula developed for merchant ships with different hull shapes is applied to fishing vessels without any modification. In this study, the modified empirical formula that can more accurately estimate the fishing vessel's maneuverability was derived by including the hull shape parameter of target fishing trawlers in the regression analysis process that derives Kijima et al. (1990) formula. As a result, the modified empirical formula showed an average estimation error of 6%, and the result improved the average error of 49% of Kijima et al. (1990) formula developed for merchant ships.

• Journal of environmental and Sanitary engineering
• /
• v.14 no.1
• /
• pp.97-102
• /
• 1999

This study was carried out view that reuse of sludge of adsorbent for benzene in carbonized cast compare with activated carbon. Not only the carbonized cast is good than carbonized carbon in cation exchange capacity and 12 adsorption capacity, but also benzene adsorption capacity is no differences compare to activated carbon. As results, benzene adsorption capacity of carbonized cast and activated carbon are decreased as temperature increase($25~70^{\circ}C$).It is compatible in Lamgmuir model. Therefore, carbonized cast is applied general adsorbent. From experimental results and data regression, in model concerning effect of temperature, relative errors between the experimental data and those calculated by the model are within the range of 1.2~7.8%. In relative humidity effect (RH 0.25~0.50) of benzene adsorption, modified Freundlich model : $QB_{enzene}{;\}QB_{enzene},{\}_{RH=0}=1-kRH^{IN}$, relative errors between the experimental data and those calculated by the model are within are range of 0.5-5.1%. The constants k and l/n in equation were found to be 1.25, 1.89 in carbonized cast.

• Proceedings of the Korea Association of Information Systems Conference
• /
• 1997.10b
• /
• pp.271-285
• /
• 1997

This paper address the issues of satisfaction factors to measure the service quality in computer communication service users. In order to develope a satisfaction factors' model, we study appropriate quality factors of the service through the focus group interviews with service users, and surveys the quality levels that users have felt in services. It also analyzes the relationship between the user's quality level and the quality factors by the statistical analyses. Based on the optimal regression model, we suggest an appropriate satisfaction model in PC communication service areas. That model shows that most users are interested in the fare for use. Use-fare factor is the most powerful one to the satisfaction model. Second one is usefulness, next is correctness. But connect-status factor is the only negative one. Most users think that its factor is in the way of fluent communication. So to keep the competitiveness in the PC communication service, the sixth negative factor should be modified as soon as possible.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1996.10a
• /
• pp.117-120
• /
• 1996

The objective of this study is to suggest modified Covariance Structure Analysis that combine with existing Multivariate Statistical Method which is used Casual Analysis Method in Management Information. For this purpose, we'll consider special feature and limitation about Correlation Analysis, Regression Analysis, Path Analysis and connect Covariance Structure Analysis with Statistical Factor Analysis so that theoretical casual model compare with variables structure in collecting data. A example is also presented to show the practical applicability of this approach.

• Journal of Korean Academy of Nursing
• /
• v.33 no.6
• /
• pp.705-712
• /
• 2003

Purpose: The purpose of this study was to explore factors that influence care dependency of institutionalized patients with dementia. Method: This study utilized descriptive correlational design. The convenience sample was composed of 110 residents with dementia of two long-term care facilities in Korea. Stepwise multiple regression was used to identify significant factors influencing care dependency in patients with dementia. Care dependency was measured using the Care Dependency Scale, Korean version(CDS-K). Cognition was measured by the MMSE-K. Functional disability was measured by the PULSES Profile. Behavioral dysfunction was measured by the modified E-BEHAVE AD. Result: Care dependency was significantly influenced by cognition, functional disability, behavioral dysfunction, and duration of dementia. This regression model explained 61 % of the variances in care dependency. Cognition explained 37% of the variances, and functional disability explained 21% of the variances. Conclusion: Results of this study suggest that professional caregivers intervene more effectively in caring for their patients with dementia by recognizing the patients cognitive, functional, behavioral disability, and its periodic change. Individually, remaining abilities-focused intervention should be applied to enhance patient to be dependent and to prevent unnecessary independency.