• Animal Bioscience
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• v.36 no.12
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• pp.1806-1820
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• 2023

Objective: The present study was aimed primarily for estimating various genetic parameters (heritability, genetic correlations) of reproduction (age at first calving [AFC], first service period [FSP]); production (first lactation milk, solid-not fat, and fat yield) and lifetime traits (lifetime milk yield, productive life [PL], herd life [HL]) in Tharparkar cattle to check the association of reproduction traits with lifetime traits through two different methods (Frequentist and Bayesian) for comparative purpose. Methods: Animal breeding data of Tharparkar cattle (n = 964) collected from Livestock farm unit of ICAR-NDRI Karnal for the period 1990 through 2019 were analyzed using a Frequentist least squares maximum likelihood method (LSML; Harvey, 1990) and a multi-trait Bayesian-Gibbs sampler approach (MTGSAM) for genetic correlations estimation of all the traits. Estimated breeding values of sires was obtained by BLUP and Bayesian analysis for the production traits. Results: Heritability estimates of most of the traits were medium to high with the LSML (0.20±0.44 to 0.49±0.71) and Bayesian approach (0.24±0.009 to 0.61±0.017), respectively. However, more reliable estimates were obtained using the Bayesian technique. A higher heritability estimate was obtained for AFC (0.61±0.017) followed by first lactation fat yield, first lactation solid-not fat yield, FSP, first lactation milk yield (FLMY), PL (0.60±0.013, 0.60±0.006, 0.57±0.024, 0.57±0.020, 0.42±0.025); while a lower estimate for HL (0.38±0.034) by MTGSAM approach. Genetic and phenotypic correlations were negative for AFC-PL, AFC-HL, FSP-PL, and FSP-HL (-0.59±0.19, -0.59±0.24, -0.38±0.101 and -0.34±0.076) by the multi-trait Bayesian analysis. Conclusion: Breed and traits of economic importance are important for selection decisions to ensure genetic gain in cattle breeding programs. Favourable genetic and phenotypic correlations of AFC with production and lifetime traits compared to that of FSP indicated better scope of AFC for indirect selection of life-time traits at an early age. This also indicated that the present Tharparkar cattle herd had sufficient genetic diversity through the selection of AFC for the improvement of first lactation production and lifetime traits.

• Journal of Technology Innovation
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• v.31 no.3
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• pp.139-169
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• 2023

This study analyzes the effects of firms' technology innovation(patent applications) on employment(number of workers and proportion of high-skilled workers) and corporate performance(sales per worker), while considering the two-way causal relationships between these variables. We used the three-stage least squares(3SLS) estimation to examine system of equations in which the dependent variables affect each other with a two-year lag wherever relevant, and applied it to firm-level panel data of Korean manufacturers with 100 or more workers. Our data covered the period of 2005-2017. Exogenous variables, such as firms' managerial and other characteristics, were controlled as explanatory variables. The identification variables for each equation included firms' R&D intensity, labor cost per worker(or operation of firms' own R&D center), and investment on worker training. We find that firms' patent applications increased number of workers, proportion of high-skilled workers, and sales per worker; the causal relationships in the opposite direction were also significant. Evidently, firms' technology innovation is critical to the growth and quality improvement of employment as well as sustainable corporate growth.

• Journal of the Korean Regional Science Association
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• v.40 no.1
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• pp.3-17
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• 2024

Despite extensive discussions on the repercussions of the prolonged COVID-19 pandemic, there is a lack of analysis on the relationships and changes in relationships between business districts Therefore, this study aims to understand the impact of COVID-19 on retail business districts in Seoul by considering the geographical dependency and interactions of these districts. Using data from the fourth quarters of 2019 to 2021 for 1,490 retail business districts in Seoul, we employed the 3-Stage Least Squares (3SLS) estimation method for simultaneous equation modeling to empirically examine how spatial dependencies among retail business districts in Seoul have evolved due to the influence of COVID-19. The results indicate the existence of spatial dependence among retail business districts in Seoul, with developmental districts exerting a negative influence on nearby districts. Furthermore, the analysis reveals changes in dependency patterns after the onset of COVID-19, interpreted as a decrease in commercial activities in developmental districts due to the impact of the pandemic. The significance of this study lies in providing new insights into Seoul's retail business districts through a spatially dependent analysis, offering a foundation for various stakeholders, including government, local authorities, and small business owners, to respond appropriately to changes in business districts by considering their interrelationships.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.3
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• pp.295-303
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• 2012

Clarify wind energy productivity depends on three factors: the wind probability density function(PDF), the turbine's power curve, and the air density. The wind PDF gives the probability that a variable will take on the wind speed value. Wind shear refers to the change in wind speed with height above ground. The wind speed tends to increase with the height above ground. also, Wind PDF refers to the change with height above ground. Wind analysts typically use the Weibull distribution to characterize the breadth of the distribution of wind speeds. The Weibull distribution has the two-parameter: the scale factor c and the shape factor k. We can use a linear least squares algorithm(or Ln-least method) and moment method to fit a Weibull distribution to measured wind speed data which data was located same site and different height. In this study, find that the scale factor is related to the average wind speed than the shape factor. and also different types of terrain are characterized by different the scale factor slop with height above ground. The gross turbine power output (before accounting for losses) was caculated the power curve whose corresponding air density is closest to the air density. and air desity was choose two way. one is the pressure of the International Standard Atmosphere up to an elevation, the other is the measured air pressure and temperature to calculate the air density. and then each power output was compared.

• Journal of Biosystems Engineering
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• v.37 no.4
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• pp.252-257
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• 2012

Purpose: The net rind pattern and color of melon surface are important for a high market value of melon fruits. The development of the net and color are closely related to the changes in shape, size, and maturing. Therefore, the net and color characteristics can be used indicators for assessment of melon quality. The goal of this study was to investigate the possibility of estimating melon soluble solids content (SSC) and firmness by analyzing the net and color characteristics of fruit surface. Methods: The true color images of melon surface obtained at fruit equator were analyzed with 18 color features and 9 texture features. The partial least squares (PLS) method was used to estimate SSC and firmness in melons using their color and texture features. Results: In sensing melon SSC, the coefficients of determination of validation (${R_v}^2$) of the prediction models using the color and texture features were 0.84 (root mean square error of validation, RMSEV: 1.92 $^{\circ}Brix$) and 0.96 (RMSEV: 0.60 $^{\circ}Brix$), respectively. The ${R_v}^2$ values of the models for predicting melon firmness using the color and texture features were 0.64 (RMSEV: 4.62 N) and 0.79 (RMSEV: 2.99 N), respectively. Conclusions: In general, the texture features were more useful for estimating melon internal quality than the color features. However, to strengthen the usefulness of the color and texture features of melon surface for estimation of melon quality, additional experiments with more fruit samples need to be conducted.

• The Korean Journal of Applied Statistics
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• v.21 no.2
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• pp.201-210
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• 2008

The government employment statistics show the close comovement of the whole domestic unemployment rate with the youth unemployment rate for the past 10 years, implying the dominant influence of the unemployment of the youth age. This study investigates the structure of the short-run variation and the process of the long-run adjustment in the unemployment rates of the youth and middle ages by formulating the dynamic equation system. The estimation result consistently reflects the vulnerability of the youth class in the aggravation of the employment condition. The effect of exogenous changes is found to be persistent in the unemployment rates of both ages, which appear to have similar structures of the long-run time path. However, the youth unemployment rate turns out to have a relatively long adjustment process to the long-run equilibrium.

• International Journal of Safety
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• v.1 no.1
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• pp.36-42
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• 2002

This paper is aimed at predicting the life of rubber insulating gloves under normal operating stresses from relatively rapid test performed at higher stresses. Specimens of rubber insulating gloves are subject to multiple stress conditions, i.e. combined electrical and thermal stresses. Two modes of electrical stress, step voltage stress and constant voltage stress are used in specimen aging. There are two types of test for electrical stress in this experiment: the one is Breakdown Voltage (BDV) test under step voltage stress and thermal stress and the other is lifetime test under constant voltage stress and temperature stress. The ac breakdown voltage defined as the break-down point of insulation that leakage current excesses a limit value, l0mA in this experiment, is determined. Because the very high variability of aging data requires the application of statistical model, Weibull distribution is used to represent the failure times as the straight line on Weibull probability paper. Weibull parameters are deter-mined by three statistical methods i.e. maximum likelihood method, graphical method and least squares method, which employ SAS package, Weibull probability paper and FORTRAN, respectively. Two chosen models for predicting the life under simultaneous electrical and thermal stresses are inverse power model and exponential model. And the constants of life equation for multistress aging are calculated using numerical method, such as Gauss Jordan method etc.. The completion of life equation enables to estimate the life at normal stress based on the data collected from accelerated aging test. Also the comparison of the calculated lifetimes between the inverse power model and the exponential model is carried out. And the lifetimes calculated by three statistical methods with lower voltage than test voltage are compared. The results obtained from the suggested experimental method are presented and discussed.

• Journal of Biosystems Engineering
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• v.33 no.4
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• pp.260-268
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• 2008

Optical diffuse reflectance sensing has potential for rapid and reliable on-site estimation of soil properties. For good results, proper calibration to measured soil properties is required. One issue is whether it is necessary to develop calibrations using samples from the specific area or areas (e.g., field, soil series) in which the sensor will be applied, or whether a general "factory" calibration is sufficient. A further question is if specific calibration is required, how many sample points are needed. In this study, these issues were addressed using data from 42 paddy fields representing 14 distinct soil series accounting for 74% of the total Korean paddy field area. Partial least squares (PLS) regression was used to develop calibrations between soil properties and reflectance spectra. Model evaluation was based on coefficient of determination ($R^2$) root mean square error of prediction (RMSEP), and RPD, the ratio of standard deviation to RMSEP. When sample data from a soil series were included in the calibration stage (full information calibration), RPD values of prediction models were increased by 0.03 to 3.32, compared with results from calibration models not including data from the test soil series (calibration without site-specific information). Higher $R^2$ values were also obtained in most cases. Including some samples from the test soil series (hybrid calibration) generally increased RPD rapidly up to a certain number of sample points. A large portion of the potential improvement could be obtained by adding about 8 to 22 points, depending on the soil properties to be estimated, where the numbers were 10 to 18 for pH, 18-22 for EC, and 8 to 22 for total C. These results provide guidance on sampling and calibration requirements for NIR soil property estimation.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.166-175
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• 1989

In this paper, we present a method which is based on the concept of the rotation of subspaces. This method is highly related to the angle (or distance) between subspaces arising in many applications. An effective procedures is first derived for finding the optimal transformation matrix which rotates one subspace into another as closely as possible in the least squares sense , and then this algorithm is applied to the solution to general direction-of-arrival estimation problem of multiple broadband plane waves which may be a mixture of incoherent, partially coherent or coherent. In this typical application, the rotation of signal subspaces (ROSS) algorithm is effectively developed to achieve the high performance in the active systems for the case in which the noise field remains invariant with the measurement of the array spectral density matrix (or data matrix). It is not uncommon to observe this situation in sonar systems. The advantage of this techniques is not to require the preliminary processing and spatial prefiltering which is used in Wang-Kaveh's CSS focusing method. Furthermore, the array's geometry is not restricted. Simulation results are presented to illustrate the high performance achieved with this new approach relative to that obtained with Wang-Kaveh's CSS focusing method for incoherent sources and forward-backward spatial smoothed MUSIC for coherent sources including the signal eigenvector method (SEM).

• Convergence Security Journal
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• v.17 no.3
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• pp.95-101
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• 2017

Reliability is the priority matter in guided weapon systems. The reliability prediction data is used during the devel opment stage as the manufacturing cost is very high and the production quantity if quite limited. At the same time it takes relatively a long period of time to acquire a reliable operation data set after deployment such that in order t o determine the operational reliability, weapons must be tested and analyzed in real operating environments. For the research, the life distributions were estimated by using actual operation data and the reliability was calculated by ap plying the method of least squares and maximum likelihood estimation. Also, the comparisons were made between pr edicted reliability and actual operational reliability. As a result, the actual reliability of each system was higher than predicted reliability and it was considered that such a difference was caused by the fact that the application of the l atest designing technology and improved parts to the guided weapon systems was not reflected on the estimation of predicted reliability. It was possible to confirm the actual operational reliability of domestic (ROK) guided weapon sy stems through this research and the methods used here will contribute to the reliability analyses for the future guide d weapon systems to be developed.