• Journal of applied mathematics & informatics
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• 제35권5_6호
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• pp.439-447
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• 2017

This paper investigates the inverse problem of determining an unknown heat radiative coefficient, which is only time-dependent. This is an ill-posed problem, that is, small errors in data may cause huge deviations in determining solution. In this paper, the existence and uniqueness of the problem is established by the second Volterra integral equation theory, and the method of trace-type functional formulation combined with finite difference scheme is studied. One typical numerical example using the proposed method is illustrated and discussed.

• Advances in Computational Design
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• 제5권2호
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• pp.177-193
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• 2020

In the present research, dynamic analysis of functionally graded (FG) graphene-reinforced beams under thermal loading has been carried out based on finite element approach. The presented formulation is based on a higher order refined beam element accounting for shear deformations. The graphene-reinforced beam is exposed to transverse periodic mechanical loading. Graphene platelets have three types of dispersion within the structure including uniform-type, linear-type and nonlinear-type. Convergences and validation studies of derived results from finite element approach are also presented. This research shows that the resonance behavior of a nanocomposite beam can be controlled by the GPL content and dispersions. Therefore, it is showed that the dynamical deflections are notably influenced by GPL weight fractions, types of GPL distributions, temperature changes, elastic foundation and harmonic load excitation frequency.

• 동력기계공학회지
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• 제2권1호
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• pp.59-66
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• 1998

The authors have studied vibration analysis algorithm which was suitable to the personal computer. Recently, we presented the transfer stiffness coefficient method(TSCM). This method is based on the concept of the transfer of the nodal dynamic stiffness coefficients which are related to force and displacement vectors at each node. In this paper, we describes the general formulation for the longitudinal and flexural coupled vibration analysis of a beam type structure by the TSCM. And the superiority of the TSCM to the finite element method(FEM) in the computation accuracy, cost and convenience was confirmed by results of the numerical computation and experiment.

• Structural Engineering and Mechanics
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• 제57권1호
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• pp.91-103
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• 2016

This investigation is concerned with the disturbances in a homogeneous transversely isotropic thermoelastic rotating medium with two temperature, in the presence of the combined effects of Hall currents and magnetic field due to normal force of ramp type. The formulation is applied to the thermoelasticity theories developed by Green-Naghdi Theories of Type-II and Type-III. Laplace and Fourier transform technique is applied to solve the problem. The analytical expressions of displacements, stress components, temperature change and current density components are obtained in the transformed domain. Numerical inversion technique has been applied to obtain the results in the physical domain. Numerically simulated results are depicted graphically to show the effects of Hall current and anisotropy on the resulting quantities. Some special cases are also deduced from the present investigation.

• Journal of applied mathematics & informatics
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• 제41권4호
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• pp.723-739
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• 2023

In this paper, we developed three theoretical models based on prey and predator that exhibit holling-type response functions. In both a fuzzy and a crisp environment, we have provided a mathematical formulation for the prey predator concept. We used the signed distance method to defuzzify the triangular fuzzy numbers using the alpha-cut function. We can identify equilibrium points for all three theoretical models using the defuzzification technique. Utilizing a variational matrix, stability is also performed with the two species model through three theoretical models. Results are presented, followed by discussion. MATLAB software is used to provide numerical simulations.

• Journal of Biosystems Engineering
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• 제19권4호
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• pp.343-357
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• 1994

Current commercial dairy feed has various problems in low feed productivity, inadequate formulation and higher feeding cost due to excessive capital investment and non-specialized system for the end product. To solve those problems, 6 TMR terminal models were developed in this study. The developed TMR terminal system consists of TMR terminal, TMR main center and combined system linked TMR terminal and TMR main center. 15 TMR main center models were developed to support 10, 20, 30, 40, 50 TMR terminal(30 ton/day basis) by 3 different types, and evaluated for capital investment and operation cost by the analysis of the newly developed computer program. Optimum model size is analyzed and suggested for each model. Followings are summary of this study : 1. The capital investment costs of TMR main centers were 1,600 to 3,800 million won for type 1, 2,200 to 4,500 million won for type 2 and 2,200 to 4,800 million won for type 3. Also model MACE30 or bigger were justified as the economical models. 2. The feed production costs of TMR main center models were 3,166 to 4,824 won/ton for type 1, 3,816 to 6,182 won/ton for type 2 and 3,990 to 6,263 won/ton for type 3. So feed production cost range was 3,166 to 6,263 won/ton. 3. The bigger production capacity, the less TMR main center production cost. The feed production cost of the biggest model MACE50 was 62~65% of smallest model MACE10.

• Toxicological Research
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• 제17권3호
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• pp.167-171
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• 2001

Oral mucous membrane test using Syrian hamsters was performed to evaluate the reliability as a model system for the assessment of the potentially irritating substances intended for the mucous membranes, and to determine the irritating potential of a new emulsion-type formulated toothpaste. After test substances were implanted into the cheek pouches of hamsters with diluents (20 mg/kg) under pento-barbital sodium anesthesia, we made the comparison in irritation between emulsion-type and dispersion-type of triclosan (TCS) formulations in the range of 0.2% to 0.3%. The emulsion-type formulations using non-ionic surfactant showed less mucosal lesion than other commercial toothpastes with 0.3% TCS, or dispersion-type ones. However, no significant difference in irritation was detected between 0.2% and 0.3% TCS. We report that this hamster cheek pouch method could be a reliable approach for the evaluation slight difference in the irritating potentials of cosmetics and hygiene products intended for the lips or other mucous membranes, and this method showed that the new emulsion-type formulation significantly lowered the TCS-induced toxicity, compared with other commercial toothpastes.

• Journal of Pharmaceutical Investigation
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• 제29권4호
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• pp.343-348
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• 1999

The purpose of this study is to prepare the controlled release adhesive patch containing naproxen. Pressuresensitive adhesive (PSA)-type patch was fabricated by casting of polyisobutylene (PIE.) and mineral oil in toluene. Membrane-controlled release (MCR)-type patch was prepared by the attachment of the controlled release membrane on the PSAtype patch. The membrane was mainly composed of Eudragit, polyethylene glycol(PEG) and glycerin. The drug release profile and skin permeation test with various patches were evaluated in vitro. The release of naproxen from PIE-based PSAtype patch with various loading doses fitted Higuchi's diffusion equation. However, the permeation of naproxen through hairless mouse skin from PSA-type patch followed zero-order kinetics. In MCR-type patch, thickness of controlled release membrane affected on the drug release rate highly. In the composition of membrane, the release rate was decreased as the ratio of Eudragit increased. The drug release from the MCR-type patch followed zero order kinetics. The permeation of naproxen through hairless mouse skin from MCR-type patch showed lag time for the intial release period and didn't fit the zero-order kinetics

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.620-623
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• 2003

The TAM (Topographic Attentive Mapping) network is a biologically-motivated neural network. Fuzzy rules are acquired from the TAM network by the pruning algorithm. In this paper we formulate a new input layer using Gabor function for TAU network to realize receptive field of human visual cortex.

• 한국경영과학회지
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• 제6권2호
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• pp.25-34
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• 1981

In this paper, we propose a non-edge following method for linear programs. Unlike alledged poor performance of algorithms of this type, this method performs well at least with 25 randomly generated problems. This method is comparable to Rosen's gradient projection method as applied to the dual formulation. The latter is of general purpose, and no implementation rules are available for linear program applications. This paper suggests ways of finding improving dual feasible directions, and of allowing to move across the extreme faces of a higher dimension polyhedron. Rather simple computational rules are provided for projection operations needed at each iteration.