• Journal of applied mathematics & informatics
• /
• v.24 no.1_2
• /
• pp.305-312
• /
• 2007

Using a weaker version of the Newton-Kantorovich theorem [6] given by us in [3], we show how to refine the results given in [8] dealing with the analyzing of the effect of small perturbations in problem data on the solution. The new results are obtained under weaker hypotheses and the same computational cost as in [8].

• Communications of the Korean Mathematical Society
• /
• v.26 no.2
• /
• pp.237-251
• /
• 2011

In this paper, we determine some stability results concerning the 2-dimensional vector variable quadratic functional equation f(x+y, z+w) + f(x-y, z-w) = 2f(x, z) + 2f(y, w) in intuitionistic fuzzy normed spaces (IFNS). We dene the intuitionistic fuzzy continuity of the 2-dimensional vector variable quadratic mappings and prove that the existence of a solution for any approximately 2-dimensional vector variable quadratic mapping implies the completeness of IFNS.

• Communications of the Korean Mathematical Society
• /
• v.28 no.4
• /
• pp.751-766
• /
• 2013

We study the existence and long-time behavior of solutions to the following semilinear degenerate parabolic equation on $\mathbb{R}^N$: $$\frac{{\partial}u}{{\partial}t}-div({\sigma}(x){\nabla}u+{\lambda}u+f(u)=g(x)$$, under a new condition concerning a variable non-negative diffusivity ${\sigma}({\cdot})$. Some essential difficulty caused by the lack of compactness of Sobolev embeddings is overcome here by exploiting the tail-estimates method.

• Journal of the Korea Safety Management & Science
• /
• v.2 no.2
• /
• pp.1-10
• /
• 2000

This study deals with the application of knowledge engineering and a methodology for the assessment and measurement of reliability, availability, maintainability, and safety of industrial systems using fault-tree representation. A fuzzy methodology for fault-tree evaluation seems to be an alternative solution to overcome the drawbacks of the conventional approach (insufficient information concerning the relative frequence of hazard events). To improve the quality of results, the membership functions must be approximated based on heuristic considerations. The purpose of this study is to describe the knowledge engineering approach, directed to integrate the various sources of knowledge involved in a FTA.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.8 no.4
• /
• pp.266-280
• /
• 1979

The renewed interest in the utilization of solar energy has revealed the need for reliable data concerning the irradiation of surfaces inclined at various angles, This report outlines the mantel in which these data were developed, presents the data in tabulated form and contains illustrative examples of how the data may be applied in the solution of solar energy utilization problems. The calculations performed and the data presented apply to latitudes 34 deg through 38 dog in South Korea.

• Korean Journal of Computational Design and Engineering
• /
• v.10 no.4
• /
• pp.293-302
• /
• 2005

The research focused quantitative comparisons of protocols occurring in the architectural massing process using two different tools, three-dimensional(3D) modeler and traditional design tools, to aid architectural massing education. Through the protocol analysis from some experiments, the research identified the following conclusions: 1) Usage of traditional tools produced much higher protocol rate in proposing solution, evaluating proposed solution, explicitness of strategies. This result seemed to be from convenience of traditional tools causing faster visual cognitive cycle. 2) Usage of 3D modeler produced much higher protocol rate concerning attempts of making design vocabulary. The result indicated 3D modeler has relatively effective functions for mass generation and orientation, however it still has some weaknesses on display interface which cause designer's lower idea generations compared to traditional design tools.

• Journal of applied mathematics & informatics
• /
• v.31 no.5_6
• /
• pp.609-621
• /
• 2013

At present, research on providing new methods to solve nonlinear integral equations for minimizing the error in the numerical calculations is in progress. In this paper, necessary conditions for existence and uniqueness of solution for nonlinear 2D Fredholm integral equations are given. Then, two different numerical solutions are presented for this kind of equations using 2D shifted Legendre polynomials. Moreover, some results concerning the error analysis of the best approximation are obtained. Finally, illustrative examples are included to demonstrate the validity and applicability of the new techniques.

• Journal of environmental and Sanitary engineering
• /
• v.10 no.3
• /
• pp.99-104
• /
• 1995

The objective of this study was to investigate the effect on denuclearization and decertification of flue gas by utilizing Mg( OH)$_{2}$ and NaOH as reagents in industrial boiler. We used packed absorber with Tellerette in all cases. And pH of circulation solution, rate of liquid per gas in absorber, COD concentration by pH variation in oxidation basin were inves- tigated. The following conclusions were obtained from experimental results: 1. Concerning running cost for reagents, Mg( OH)$_{2}$ reagent for treatment of flue gas was more economical than NaOH. 2. While Mg( OH )$_{2}$ and NaOH as absorbents were used, then the ratio of denuclearization was 96 and 97% respectively and nitrification was recorded 29 and 25% . 3. In this absorption tests the optimum condition for ratio of liquid per gas, pH and nonregenerable salt concentration of circulation solution were 3.6ℓ /Nm$^{3}$, 6.0, 0.5∼1.0% respectively, 4. Initial COD in oxidation basin was 800 ∼ 1,00099ut after adjusting to pH 7.0, COD of effluent water was less than 20ppm.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.21-22
• /
• 2006

Significant progress has been realized in the design and synthesis of light emitting polymers with emission over the whole range of the visible spectrum. However up to seventy-five percent of charge recombination events can lead to triplet states that decay non-radiatively. Following the pioneering work in the field of small molecule organic light emitting devices it has been found that solution processible iridium polymer complexes can be used to harness the wasted triplet energy. In this paper new results concerning electrophosphorescence of solution processible tethered iridium polymer derivatives will be presented. Furthermore our approaches to the design of new high triplet energy conjugated polymer hosts will be reported.

• The Journal of Korean Academy of Prosthodontics
• /
• v.9 no.1
• /
• pp.41-45
• /
• 1969

A major disadvantage of Dental cements is their solubility. So it is very important to measure the exact amount of solubility to select clinically suitable materials. The most common laboratory test for solubility is the measurement of disintegration in distilled water, as outlined in A.D.A. Specifications 8 and 9, In addition to the possible factors influencing the solubility, the experiments were all conducted in compliance with A.D.A. Specifications. The solubility of 2 Zinc Phosphate cements and 1 Silicate cement in time of dissolution, concentration of solute in dissolving medium, and type of dissolving medium were investigated. The following results were obtained. 1. Generally the materials were more soluble in organic acids than in distilled water. 2. The dissolution cements tends be minimized by tests utilizing prolonged storage in the same media. 3. In Acetic acid solution, Zinc Phosphate cements were more soluble than Silicate cement, and in Citric acid solution both were markedly more soluble. 4. Solubility was increased by continually presenting fresh liquid, unsaturated with solute, to the cement-water interface.