• Steel and Composite Structures
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• v.4 no.6
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• pp.453-469
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• 2004

In this article, a genetic algorithm based optimum design method is presented for non-linear steel frames with semi-rigid connections. The design algorithm obtains the minimum weight frame by selecting suitable sections from a standard set of steel sections such as European wide flange beams (i.e., HE sections). A genetic algorithm is employed as optimization method which utilizes reproduction, crossover and mutation operators. Displacement and stress constraints of Turkish Building Code for Steel Structures (TS 648, 1980) are imposed on the frame. The algorithm requires a large number of non-linear analyses of frames. The analyses cover both the non-linear behaviour of beam-to-column connection and $P-{\Delta}$ effects of beam-column members. The Frye and Morris polynomial model is used for modelling of semi-rigid connections. Two design examples with various type of connections are presented to demonstrate the application of the algorithm. The semi-rigid connection modelling results in more economical solutions than rigid connection modelling, but it increases frame drift.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.779-783
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• 2021

The amount of sunlight (irradiation) acts as a very important factor for paprika (Capsicum annuum L.) productivity, but there are difficulties in developing a standard model for estimating paprika productivity using irradiation factors. This study was conducted to investigate how to increase the suitability of using irradiation as an independent variable when developing a standard model. In the linear regression analysis using the independent variable (cumulative irradiation) and the dependent variable (cumulative productivity) were classified as the average value of the total farm productivity (MTFP), and above and below (MHFP, MLFP) based on the average value, respectively. The RMSE value of the estimated linear regression model was 0.9418 kg·m^-2 in the MHFP, which was significantly lower than 1.5468 kg·m^-2 in the MTFP and 1.3812 kg·m^-2 in the MLFP. And in due course of time (month), RMSE value was also the lowest in MHFP, below 1.0 kg·m^-2 in all months. Therefore, when developing a regression model for estimating paprika productivity using irradiation, it is judged that it will improve the suitability of the estimation model by classifying and analyzing the difference in productivity of farms with an appropriate method.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.3
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• pp.262-272
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• 2023

A polymer-based mechanical low-pass filter(m-LPF) for high-g accelerometers makes it possible to remove high-frequency transient noises from acceleration signals, thus ensuring repeatable and reliable measurement on high-g acceleration. We establish a prediction model for performance of m-LPF by combining a fundamental vibration model with the fractional derivative standard linear solid(FD SLS) model describing the storage modulus and loss modulus of polymers. Here, the FD SLS model is modified to consider the effect of m-LPF shape factor (i.e., thickness) on storage modulus and loss modulus. The prediction accuracy is verified by comparing the displacement transmissibility(or cut-off frequency) estimated using our model with that measured from 3 kinds of polymers(polysulfide rubber(PSR), silicone rubber(SR), and polydimethylsiloxane(PDMS)). Our findings will contribute a significant growth of m-LPF for high-g accelerometers.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.85-92
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• 2002

To investigate the safety of the in-use vehicles emission against the tail-pipe emission regulation, in-use vehicles emission trend according to vehicle mileage should be known. But it is impossible to collect all vehicles emission data In order to know that. Therefore, it is necessary to establish a statistically meaningful inference method that can be used generally to estimate in-use vehicles emissions distribution according to the vehicle mileage with relatively less in-use vehicles emission data. To do this, a linear regression model that solved the problems of data normality and common variance of error was studied. As a way that can secure the data normality, In(emission) instead of emission itself was used as a sampled data. And a reciprocal of mileage was suggested as a factor to secure common variance of error. As an example, 36 data of FTP-75 test were handled in this study. As a result, using average value and standard deviation at each mileage which were inferred from a linear regression model, probability density distribution and cumulative distribution of emissions according to the vehicle mileage were obtained and it was possible to predict the deterioration factor through full useful life mileage and also possible to decide whether those in-use vehicles will meet the tail-pipe emission regulations or not.

• Journal of the Korean Operations Research and Management Science Society
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• v.14 no.2
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• pp.105-114
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• 1989

The actual working time of jobs, in general, is different to the standard time of jobs. In this paper, in order to analyze the actual working time of each job in production, we use the total production amount and the encessary total working time. The method which analyzes the actual working time is as follows. In this paper, we propose the interval regression analysis for obtaining an interval linear regression model with constraint conditions with respect to interval parameters. The merits of this method are the following.1) it is easy to obtain an interval linear model by solving a LP problem to which the formulation of proposed regression analysis is reduced, 2) it is easy to add constraint conditions about interval parameters, which are a sort of expert knowledge. As an application, within a case which has given certain data, the actual working time of jobs and the number of workers in a future plan are estimated through the real data obtianed from the operation of processing line in a heavy industry company. It results from the proposed method that the actual working time and the number of workers can be estimated as intervals by the interval regression model.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.188-195
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• 2000

This study was conducted to measure the moisture content of powdered food using RF impedance spectroscopic method. In frequency range of 1.0 to 30㎒, the impedance such as reactance and resistance of parallel plate type sample holder filled with wheat flour and red-pepper powder of which moisture content range were 5.93∼-17.07%w.b. and 10.87 ∼ 27.36%w.b., respectively, was characterized using by Q-meter (HP4342). The reactance was a better parameter than the resistance in estimating the moisture density defined as product of moisture content and bulk density which was used to eliminate the effect of bulk density on RF spectral data in this study. Multivariate data analyses such as principal component regression, partial least square regression and multiple linear regression were performed to develop one calibration model having moisture density and reactance spectral data as parameters for determination of moisture content of both wheat flour and red-pepper powder. The best regression model was one by the multiple linear regression model. Its performance for unknown data of powdered food was showed that the bias, standard error of prediction and determination coefficient are 0.179% moisture content, 1.679% moisture content and 0.8849, respectively.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.15 no.2
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• pp.203-214
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• 2011

Objectives: The objective of the current study is to determine whether an ultrasound device system is adequate for measuring distance from the abdominal surface of Sangwan (CV13) to peritoneum in front of anterior surface of liver. Methods: We recruited 3 healthy young male subjects and 2 sonographers. The each sonographer measured vertical shortest distance from the abdominal surface of Sangwan (CV13) to peritoneum in front of anterior surface of liver with a ultrasound device with three methods of 3.5 MHz convex probe and gel, 9 MHz linear probe and gel, and 9 MHz linear probe and solid gel pad, three times in random order. Because the total variation could be divided into repeatability, reproducibility and subject-to-subject variation in Gage R&R method, we compared the sources of variation associated with the measurement system with an analysis of variance model. Results & Conclusions: Number of distinct categories is calculated on the basis of standard deviation of subject-to-subject divided by standard deviation of total Gage R&R. If the number of categories is five or more, the measurement system may be acceptable for the analysis of the process. The number of distinct categories of the ultrasound device system for measuring distance from the abdominal surface of Sangwan (CV13) to peritoneum in front of anterior surface of liver were 9.20 (9 MHz linear probe and gel), 14.70 (9 MHz linear probe and solid gel pad). So we concluded that repeatabilities and reproducibilities of the ultrasound device system for measuring distance from the abdominal surface of Sangwan (CV13) to peritoneum in front of anterior surface of liver with the methods of 9 MHz linear probe and gel, and 9 MHz linear probe and solid gel pad were acceptable.

• Proceedings of the Korean Statistical Society Conference
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• 2000.11a
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• pp.187-191
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• 2000

In the analysis of repeated measurements, multivariate regression models that account for the correlations among the observations from the same subject are widely used. Like the usual univariate regression models, these multivariate regression models also need some model diagnostic procedures. In this paper, we propose a simple graphical method to detect outliers and to investigate the goodness of model fit in repeated measures data. The graphical method is based on the quantile-quantile(Q-Q) plots of the $X^2$ distribution and the standard normal distribution. We also propose diagnostic measures to detect influential observations. The proposed method is illustrated using two examples.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.131-136
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• 1998

Based on the linear model of electromagnetic suspension (EMS) system, it is able to be further simplified into a standard second-order model with a modified PD control. In this paper static and dynamic characteristics of EMS with modified PD control are investigated when suspended weight of steel plate change. A experimental system has been built to verify static and dynamic characteristics of EMS system. Simulation and experiment are both given.

• Journal of Astronomy and Space Sciences
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• v.7 no.2
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• pp.73-103
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• 1990

Morphological luminosity parameters$(\mu_e,\;r_e,\;\mu_0,\;\alpha^{-1})$ and D/B were estimated from the decomposition of surface brightness distributions of 28 extra galaxies. Decomposition was made using the standard non-linear least square fitting method and we used the seeing convolved model to get the central brightness of these galaxies. Masses and $M/L_B$ were calculated using rotational velocities of these galaxies from the fitting to the generalized Toomre's mass model.