• Bulletin of the Korean Mathematical Society
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• v.53 no.6
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• pp.1671-1683
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• 2016

Abstract. In this paper, for $a{\in}C$, we investigate functions $g_a$ and ${\psi}_a$ associated with three term relations. $g_a$ is defined by means of function ${\psi}_a$. By using these functions, we obtain some functional equations related to the Eisenstein series and the Riemann zeta function. Also we find a generalized difference formula of function $g_a$.

• Korean Journal of Biological Psychiatry
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• v.1 no.1
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• pp.109-116
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• 1994

It is not known whether negative symptoms and cognitive functions are dissociable or improvements in symptoms are reflected in improvements in cognitive functions in chronic schizophrenic patients. We administered clozapine to evaluate its effect on cognitive functions in chronic schizophrenic patients and to show correlations between improvement in psychotic symptoms and in cognitive functions. Neuropsychological tests such as Wisconsin Card Sorting Test, Digit Span test and Judgment of Line Orientation Test were applied to 16 chronic schizophrenic patients at baseline and after 9 months of treatment with clozapine. Using BPRS we assessed psychopathology before initiation of clozapine and at 9 months. Clozapine improved both positive and negative symptoms in chronic schizophrenic patients significantly. After nine months of clozapine treatment, significant improvements occurred in attention, short-term memory and visual perception ability. And interestingly we noted the trend of improvement in executive functions even though they were not statistical significant. Any significant correlations between the clinical improvement and change in congnitive functions were not observed. Long-term treatment with clozapine improved parts of cognitive functions of chronic schizophrenics. The results of the study suggest that deficits in simple cognitive functions as well as psychotic symptoms are improved after 3 month period of short-term treatment, but executive functions requiring more sophisticated processing of information could be improved after more than 9 months of long-term treatment.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.12
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• pp.54-60
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• 1997

A new method to neglect the third term of the computational energy expression in the single-layer neural network with feedback is introduced. The system often converges to local minima instead of to global minima, because the computational energy is not matched exactly with the cost function being optimized. One of the factors causing these tow functions different is the third term of computational enegy expression. Regarding this third term energy very small, it is always ignored in designing the system. However, a sthe system growing, this third term energy is also growing and this grown term makes the computational energy function much different from the cost function. In results of differency between two functions, system converges to local minima more than before. In this paper, a new method to neglect te third term energy is introduced, so that the system with tis new method has been imroved.

• Communications for Statistical Applications and Methods
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• v.24 no.4
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• pp.325-337
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• 2017

In this paper, we proposed a new long-term lifetime distribution with four parameters inserted in a risk competitive scenario with decreasing, increasing and unimodal hazard rate functions, namely the Weibull-Poisson long-term distribution. This new distribution arises from a scenario of competitive latent risk, in which the lifetime associated to the particular risk is not observable, and where only the minimum lifetime value among all risks is noticed in a long-term context. However, it can also be used in any other situation as long as it fits the data well. The Weibull-Poisson long-term distribution is presented as a particular case for the new exponential-Poisson long-term distribution and Weibull long-term distribution. The properties of the proposed distribution were discussed, including its probability density, survival and hazard functions and explicit algebraic formulas for its order statistics. Assuming censored data, we considered the maximum likelihood approach for parameter estimation. For different parameter settings, sample sizes, and censoring percentages various simulation studies were performed to study the mean square error of the maximum likelihood estimative, and compare the performance of the model proposed with the particular cases. The selection criteria Akaike information criterion, Bayesian information criterion, and likelihood ratio test were used for the model selection. The relevance of the approach was illustrated on two real datasets of where the new model was compared with its particular cases observing its potential and competitiveness.

• Research in Community and Public Health Nursing
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• v.19 no.2
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• pp.260-269
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• 2008

Purpose: The purpose of this study was to identify differences in health status and the utilization of long-term care service between urban and rural aged residents in Korea. Methods: Through convenience sampling, 1,405 elders (829 from urban areas and 576 from rural areas) were selected during March 1 to May 31 in 2004. All the subjects agreed to participate and filled out the survey questionnaire after signing the consent form. The instruments utilized in this study were the impairment of physio-sensory function, ADL IADL, cognitive function, and psycho-social function scale. This instrument was developed by modifying the scab developed by Gurland & Wilder (1984). Data was analyzed using the SPSS Win program. Results: There were significant differences in economic status, duration of living and type of medical insurance between rural and urban elderly(p<.05). Physio-sensory functions (t=4.53. p<.001), ADL (t=3.61. p<.001), IADL (t=2.45, p=.014), cognitive functions (t=-2.63. p=.024) and psycho-social functions (t=3.69. p<.001) were significantly different between the two groups. The utilization of long-term care facility in the urban elderly was significantly higher than that in the rural elderly ($x^2=10.14$, p<.001). Conclusion: Considering these findings. the need for long-term care should be assessed by residence characteristics. Because of different utilization of long term care facility according to the elderly's needs, long-term care services should be considered the residence characteristics.

• Bulletin of the Korean Mathematical Society
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• v.50 no.1
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• pp.233-240
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• 2013

In this paper, we use the elementary method and the theory of complex functions to study the computational problem of the fourth power mean of the generalized two-term exponential sums, and give two exact identities for them.

• Journal of the Korean Data and Information Science Society
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• v.14 no.3
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• pp.623-630
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• 2003

Recently, Tanaka(1988) derived two influence functions related to an eigenvalue problem $(A-\lambda_sI)\upsilon_s=0$ of real symmetric matrix A and used them for sensitivity analysis in principal component analysis. In this paper, we deal with the perturbation expansions up to quadratic terms of the same functions and discuss the application to sensitivity analysis in principal component regression analysis(PCRA). Numerical example is given to show how the approximation improves with the quadratic term.

• Structural Engineering and Mechanics
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• v.62 no.6
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• pp.725-737
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• 2017

An analytical method considering axial equilibrium is proposed for the short- and long-term analyses of shear lag effect in reinforced concrete (RC) box girders. The axial equilibrium of box girders is taken into account by using an additional generalized displacement, referred to as the longitudinal displacement of the web. Three independent shear lag functions are introduced to describe different shear lag intensities of the top, bottom, and cantilever plates. The time-dependent material properties of the concrete are simulated by the age-adjusted effective modulus method (AEMM), while the reinforcement is assumed to behave in a linear-elastic fashion. The differential equations are derived based on the longitudinal displacement of the web, the vertical displacement of the cross section, and the shear lag functions of the flanges. The time-dependent expressions of the generalized displacements are then deduced for box girders subjected to uniformly distributed loads. The accuracy of the proposed method is validated against the finite element results regarding the short- and long-term responses of a simply-supported RC box girder. Furthermore, creep analyses considering and neglecting shrinkage are performed to quantify the time effects on the long-term behavior of a continuous RC box girder. The results show that the proposed method can well evaluate both the short- and long-term behavior of box girders, and that concrete shrinkage has a considerable impact on the concrete stresses and internal forces, while concrete creep can remarkably affect the long-term deflections.

• Journal of the Korean Mathematical Society
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• v.55 no.6
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• pp.1469-1483
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• 2018

We study a subclass of p-ary functions in n variables, denoted by ${\mathcal{A}}_n$, which is a collection of p-ary functions in n variables satisfying a certain condition on the exponents of its monomial terms. Firstly, we completely classify all p-ary (n - 1)-plateaued functions in n variables by proving that every (n - 1)-plateaued function should be contained in ${\mathcal{A}}_n$. Secondly, we prove that if f is a p-ary r-plateaued function contained in ${\mathcal{A}}_n$ with deg f > $1+{\frac{n-r}{4}}(p-1)$, then the highest degree term of f is only a single term. Furthermore, we prove that there is no p-ary r-plateaued function in ${\mathcal{A}}_n$ with maximum degree $(p-1){\frac{n-4}{2}}+1$. As application, we partially classify all (n - 2)-plateaued functions in ${\mathcal{A}}_n$ when p = 3, 5, and 7, and p-ary bent functions in ${\mathcal{A}}_2$ are completely classified for the cases p = 3 and 5.

• Communications of Mathematical Education
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• v.23 no.3
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• pp.923-951
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• 2009

In this paper, we have analyzed the term examinations on quadratic equations and functions in middle schools based on the object of evaluations given by the ministry of education, science and technology of Korea.