• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.147-157
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• 2009

Recently, there has been continued research on UCP from the development effort estimation method to a software development project applying object oriented development methodology. Current research proposes a linear model estimating the developmenteffort by multiplying a constant to AUCP which applies technical and environmental factors. However, the fact that a non-linear regression model is more appropriate as the software size increases, the development period increases exponentially. In addition, in the UCP calculation process the occurrence of FP errors due to the application of TCF and EF, it is unrealistic to estimate the size with AUCP. This paper presents the issue of current research based on UCP without considering problems of the research, for example, TCF and EF and expresses the models (linear, logarithmic, polynomial, power and exponential type) estimating the development effort directly from UUCP. Consequently, the exponential model within non-linear models exhibit more accurate results than the current linear model. Therefore, after calculating the UUCP of the developing software system, using the proposed model to estimate the development effort, it is possible to estimate the direct cost required in development.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.6
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• pp.397-404
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• 2019

Linear Shaped Charge (LSC) that is widely used as separation system in aerospace system has to charge lots of explosives due to lack of uniformity. In addition, it is hard to optimize shape of liner and explosives because of manufacturing process. In order to overcome aforementioned drawbacks, Precision Linear Shaped Charge (PLSC) is currently under development. PLSC is made in two steps: prepare liner independently and charge explosive uniformly. In this study, PLSC is designed to have proper amount of explosives and penetration test of PLSC with different stand-off distance from liner to target is conducted to confirm penetration performance. Based on the penetration test results of PLSC, the numerical analysis method using AUTODYN is established and verified. Penetration mechanism and characteristics of PLSC is analyzed from the numerical and experimental results.

• Journal of Agricultural Extension & Community Development
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• v.13 no.2
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• pp.265-276
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• 2006

This study focused on the trends in recognising an economic concern as the most difficult problem in the farm household that was categorised as a full-time farm household or a part-time household according to income structure from agricultural activity. Log-linear models were suggested to compare the change of recognising an economic problem between year 2003 and 2005. As a result, there was no significant difference in recognising an economic problem between full-time farm household and part-time farm household both in 2003 ($x^2$＝0.04;p＝0.84) and in 2005 ($x^2$＝1.08; p＝0.30). It was revealed, however, that full-time farm household had increasingly recognised an economic problem over years. Log-linear models showed that full-time farm households tended to recognise the economic problem 1.11 times as much as part-time farm households in 2005, compared to 0.97 times in 2003.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.7
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• pp.667-672
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• 2009

This paper is concerned with the development of linear magnetic actuator for active vibration control. The newly developed linear magnetic actuator consists of permanent magnets and copper coils. On the contrary to the voice-coil type actuator, the linear magnetic actuator utilizes magnetic flux to generate the shaft movement. In this study, experiments on the prototype linear magnetic actuator were carried out to investigate its dynamic characteristics. Block and inertia forces generated by the actuator were measured. The experimental results show that the actuator can be used as both actuator and active tuned-mass damper. The linear magnetic actuator was attached to a cantilever as the active-tuned mass damper and active vibration control experiment was carried out. The experimental results show that the newly developed linear magnetic actuator can be effectively used for the active vibration control of structures.

• The Korean Journal of Applied Statistics
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• v.13 no.2
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• pp.541-562
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• 2000

The generalized linear mixed model framework is for handling count-type categorical data as well as for clustered or overdispersed non-Gaussian data, or for non-linear model data. In this study, we review its general formulation and estimation methods, based on quasi-likelihood and Monte-Carlo techniques. The current research areas and topics for further development are also mentioned.

• Journal for History of Mathematics
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• v.37 no.2
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• pp.21-38
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• 2024

In this article, we study the historical development of how the main concepts of linear algebra - matrices, vectors, and transformations - arise, are connected then integrated into a category. Also we study how linearity is recognized and integrated into algebraic and geometric viewpoint. Furthermore, we discuss, based on this, the role of linear algebra as a unifying concept in a school mathematics.

• The KIPS Transactions:PartD
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• v.11D no.1
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• pp.163-172
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• 2004

In the software development project applying object-oriented development methodology, the research on the UCP(Use Case Point) as a method to estimate development effort is being carried on. The existing research proposes the linear model calculating the development effort that multiplies an invariant on AUCP(Adjusted Use Case Point) which applied technical and environmental factors. However, the statistical model that estimates the development effort using AUCP and UUCP(Unadjusted Use Case Point) is not being studied. The irrelevant relationship of the linear regression model, whose development period is increasing tremendously as the software size increases, is confirmed. Moreover, during the UCP calculating process, there can be errors in FP by applying the TCF(Technical Complexity Factor) and EF(Environmental Factor). This paper presents a non-linear regression model, that does not consider the TCF and EF, and that estimate the development effort from UUCP directly by utilizing the exponential function. An exponential function is selected among the linear, logarithm, polynomial, power, and exponential model via statistical evaluations of the models mentioned above.

• Journal of Agricultural Extension & Community Development
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• v.23 no.2
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• pp.123-133
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• 2016

According to increasing the number of rice farm households, it is important to find optimal farm scale, farm crops, and labour constraints depending on growth time. The study aims to analyze the optimal farming system using the linear programming in Seosan county, Chungnam. The survey was conducted in-depth interview to collect data from one farm household. Results show that farmers change their some crops in dry filed into ginger and hire farm labours in April. The findings should be of interest to rice farmers and policy makers to manage their farm effectively and to support them.

• Animal Bioscience
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• v.37 no.4
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• pp.622-630
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• 2024

Objective: Pig breeders cannot obtain phenotypic information at the time of selection for sow lifetime productivity (SLP). They would benefit from obtaining genetic information of candidate sows. Genomic data interpreted using deep learning (DL) techniques could contribute to the genetic improvement of SLP to maximize farm profitability because DL models capture nonlinear genetic effects such as dominance and epistasis more efficiently than conventional genomic prediction methods based on linear models. This study aimed to investigate the usefulness of DL for the genomic prediction of two SLP-related traits; lifetime number of litters (LNL) and lifetime pig production (LPP). Methods: Two bivariate DL models, convolutional neural network (CNN) and local convolutional neural network (LCNN), were compared with conventional bivariate linear models (i.e., genomic best linear unbiased prediction, Bayesian ridge regression, Bayes A, and Bayes B). Phenotype and pedigree data were collected from 40,011 sows that had husbandry records. Among these, 3,652 pigs were genotyped using the PorcineSNP60K BeadChip. Results: The best predictive correlation for LNL was obtained with CNN (0.28), followed by LCNN (0.26) and conventional linear models (approximately 0.21). For LPP, the best predictive correlation was also obtained with CNN (0.29), followed by LCNN (0.27) and conventional linear models (approximately 0.25). A similar trend was observed with the mean squared error of prediction for the SLP traits. Conclusion: This study provides an example of a CNN that can outperform against the linear model-based genomic prediction approaches when the nonlinear interaction components are important because LNL and LPP exhibited strong epistatic interaction components. Additionally, our results suggest that applying bivariate DL models could also contribute to the prediction accuracy by utilizing the genetic correlation between LNL and LPP.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.6
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• pp.531-540
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• 2007

While determination of the solid propellant burning rates by ultrasound, it has been reported that the frequent data scatters were caused by two major factors; 1) variation in the acoustical properties, and 2) non-linear burning of a solid propellant sample under investigation. This work is carried out for the purpose of investigating the effect of non-linear burning of solid propellant samples. Specifically, we propose an ultrasonic measurement model that can predict the reflections from solid propellant surfaces with non-linear burning by the combination of two ingredients; 1) a pulse-echo ultrasonic measurement model for a planar, circular reflector imbedded in the second medium in an immersion set-up, and 2) an efficient model of non-linear burning surfaces with a number of small, planar circles. Then, we demonstrate the capability of the proposed measurement model by simulation of the surface echo signals from four different burning surfaces that have been generated by the combination of two factors; the base shape (flat or paraboloidal) and the surface roughness (perfectly smooth or randomly rough). From the simulation presented here, we can confirm the fact that the non-linear burning of the propellant can cause the waveform change of the burning surface echo and the corresponding spectrum variation.