• Korean Journal of Mathematics
• /
• v.28 no.2
• /
• pp.295-309
• /
• 2020

In this paper we study the growth of solutions of some non-linear complex differential equations in connection to Brück conjecture using the theory of complex differential equation.

• Korean Journal of Mathematics
• /
• v.29 no.1
• /
• pp.65-73
• /
• 2021

In this paper, we investigate the growth properties of solutions of the non-homogeneous linear complex differential equation L(f) = b (z) f + c (z), where L(f) is a linear differential polynomial and b (z), c (z) are entire functions and give some of its applications on sharing value problems.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.7
• /
• pp.718-726
• /
• 2009

The objective of this study was to develop and validate secondary models that can predict growth parameters of L. monocytogenes Scott A as a function of concentrations (0-3%) of a commercial potassium lactate (PL) and sodium diacetate (SDA) mixture, pH (5.5-7.0), and temperature (4-37DC). A total of 120 growth curves were fitted to the Baranyi primary model that directly estimates lag time (LT) and specific growth rate (SGR). The effects of the variables on L. monocytogenes Scott A growth kinetics were modeled by response surface analysis using quadratic and cubic polynomial models of the natural logarithm transformation of both LT and SGR. Model performance was evaluated with dependent data and independent data using the prediction bias ($B_f$) and accuracy factors ($A_f$) as well as the acceptable prediction zone method [percentage of relative errors (%RE)]. Comparison of predicted versus observed values of SGR indicated that the cubic model fits better than the quadratic model, particularly at 4 and $10^{\circ}C$. The $B_f$and $A_f$for independent SGR were 1.00 and 1.08 for the cubic model and 1.08 and 1.16 for the quadratic model, respectively. For cubic and quadratic models, the %REs for the independent SGR data were 92.6 and 85.7, respectively. Both quadratic and cubic polynomial models for SGR and LT provided acceptable predictions of L. monocytogenes Scott A growth in the matrix of conditions described in the present study. Model performance can be more accurately evaluated with $B_f$and $A_f$and % RE together.

• Journal of Satellite, Information and Communications
• /
• v.3 no.1
• /
• pp.15-21
• /
• 2008

The high peak to average power ratio (PAPR) of OFDM (Orthogonal Frequency Division Multiplexing) system introduces inevitable non-linear distortion in the transmission due to the amplifier non-linear property. This causes both in-band distortion and out of band spectrum re-growth. In this paper we tried to compensate the problem by using polynomial based pre-distortion. Estimation of both the non-linear and inverse non-linear polynomial is achieved using the Least Square Error (LSE) method. Using these parameters closed form pre-distorter can be easily created. We also used the 'partial peak cancellation and clipping' method to remove the high peak present in the non constant amplitude of the OFDM signal responsible to drive the amplifier in near saturation region for better performance of the system

• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2627-2629
• /
• 2003

In this paper, we propose a new architecture of Genetic Algorithms(GAs)-based Self-Organizing Polynomial Neural Networks(SOPNN). The conventional SOPNN is based on the extended Group Method of Data Handling(GMDH) method and utilized the polynomial order (viz. linear, quadratic, and modified quadratic) as well as the number of node inputs fixed (selected in advance by designer) at Polynomial Neurons (or nodes) located in each layer through a growth process of the network. Moreover it does not guarantee that the SOPNN generated through learning has the optimal network architecture. But the proposed GA-based SOPNN enable the architecture to be a structurally more optimized networks, and to be much more flexible and preferable neural network than the conventional SOPNN. An aggregate performance index with a weighting factor is proposed in order to achieve a sound balance between approximation and generalization (predictive) abilities of the model. To evaluate the performance of the GA-based SOPNN, the model is experimented with using nonlinear system data.

• Journal of the Korean Society of Safety
• /
• v.8 no.4
• /
• pp.183-188
• /
• 1993

Anthropometric characteristics and considerations of sex differences are essential for the correct design of ergonomic work spaces. This paper is concerned with longitudinal study on the physical growth in Korean youth. Three hundred eighty-seven subjects were selected from third year students of high schools, and their records on physical examination during the last twelve years were surveyed by longitudinal method. For boys and girls, this study investigated the anthropometric characteristics of physical structure and the shape of physical growth. The result showed that the physical growth spurt of girl occurred earlier than that of boy. Also, by regression analysis, the third-order polynomial function was suitable for the growth curves of stature and weight, and there were significant sex differences in the fitted curves.

• Journal of the Korean Society of Tobacco Science
• /
• v.2 no.2
• /
• pp.44-50
• /
• 1980

The growth of flue-cured tobacco was analyzed with the mathematical treatment. The results are summarized as followings: 1. The growth curve was fitted to the quadratic polynomial equation in improved-mulching cultivation, blot to the Gompertz equation in the other cultivations. 2. The initial point of the maximum growth phase for dry weight was about 50 days after transplanting in improved-mulching cultivation, but about 40 days in the other cultivations, and the maximum growth period was for 25 days in all cultivations. 3. The growth rate of the maximum growth period in dry weight decreased in the order of improved-mulching cultivation, mulching cultivation, and non-mulching cultivation. 4. A relative growth amount in the maximum growth period was higher in later sowing. 5. The length of maximum growth was 5 days shorter in leaf area than in dry weight. The maximum growth phase was 7 days earlier in leaf area than in dry weight.

• Journal of the korean Society of Automotive Engineers
• /
• v.14 no.2
• /
• pp.65-75
• /
• 1992

An analytical scheme for predicting the crack aspect pattern of materials which contain twin surface cracks was developed. Fatigue tests were performed on twin surface cracked PMMA plate specimens to obtain the interaction factor accounting for the interference effect of adjacent cracks. Here, the interaction factor is defined as the ratio of the stress intensity factor for twin surface cracks to that for a single surface crack. From the analysis of the fatigue test result, the interaction factor was presented as the ninth-order polynomial expression having a function of dimensionless crack spacing ratio. Then the polynomial expression was incorporated into the prediction program of the crack aspect pattern for twin surface cracked materials. And, the interaction effect and the coalescence condition of adjacent cracks were simplified in the newly developed prediction scheme of the crack aspect pattern. The predicted crack growth pattern using the prediction scheme was compared with test data from PMMA specimen. The predicted pattern agreed well with the test data.

• Bulletin of the Korean Mathematical Society
• /
• v.39 no.4
• /
• pp.687-704
• /
• 2002

We show that the class of inner chordarc domains is properly contained in the class of exterior quasiconvex domains. We also show that the class of exterior quasiconvex domains is properly contained in the class of John disks. We give the conditions which make the converses of the above results be true. Next , we show that an exterior quasiconvex domain satisfies certain growth conditions for the exterior Riemann mapping. From the results we show that the domain satisfies the Bernstein inequality and the integrated version of it. Finally, we assume that f is a function which is continuous in the closure of a domain D and analytic in D. We show connections between the smoothness of f and the rate at which it can be approximated by polynomials on an exterior quasiconvex domain and a $Lip_\alpha$-extension domain.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.3 no.3
• /
• pp.309-330
• /
• 2009

In this paper, we introduce the architecture of Genetic Algorithm(GA) based Feed-forward Polynomial Neural Networks(PNNs) and discuss a comprehensive design methodology. A conventional PNN consists of Polynomial Neurons, or nodes, located in several layers through a network growth process. In order to generate structurally optimized PNNs, a GA-based design procedure for each layer of the PNN leads to the selection of preferred nodes(PNs) with optimal parameters available within the PNN. To evaluate the performance of the GA-based PNN, experiments are done on a model by applying Medical Imaging System(MIS) data to a multi-variable software process. A comparative analysis shows that the proposed GA-based PNN is modeled with higher accuracy and more superb predictive capability than previously presented intelligent models.