• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제8권2호
• /
• pp.111-115
• /
• 2008

By generalizing the definition of fuzzy weakly semicontinuous mappings by B. S. Zhong, we introduce the concept of fuzzy weakly r-semicontinuous mappings in fuzzy topology of Chattopadhyay. Then the concept introduced by B. S. Zhong becomes a special case of our definition. Also, we show that fuzzy weakly r-semicontinuity and fuzzy weakly r-continuity are independent notions.

• 한국지능시스템학회:학술대회논문집
• /
• 한국퍼지및지능시스템학회 2006년도 추계학술대회 학술발표 논문집 제16권 제2호
• /
• pp.149-152
• /
• 2006

By generalizing the definition of B. S. Zhong, we introduce the concept of fuzzy weakly ${\gamma}-semicontinuous$ maps in fuzzy topology of Chattopadhyay. Then the concept introduced by B. S. Zhong become special case of our definition. Also, we show that fuzzy weakly ${\gamma}-semicontinuity$ and fuzzy weakly ${\gamma}-continuity$ are independent notions.

• 대한기계학회논문집B
• /
• 제21권3호
• /
• pp.414-426
• /
• 1997

Numerical computations were conducted to characterize the three-dimensional laminar flow through an injector orifice having an inclined angle of 30 .deg.. For this study, the incompressible Navier-Stokes equations in generalized curvilinear coordinates, using a pseudocompressibility approach for continuity equation, were solved. The computations were performed using the finite difference implicit, approximately factored scheme of Beam and Warming and multi-block grids of complete continuity at block interfaces. The multi-block computations were validated for the steady state using direct comparison of multi-block solutions with equivalent single-block ones, including 2-D 180.deg. TAD and 3-D 90.deg. pipe bend. The comparisons between the numerical solutions and the flow field measurements for a tube with sudden contraction were presented in this work for solution validation. Computational results showed the nature of complex flow fields within the inclined injector orifice, including strong pressure-driven secondary flows in the cross stream induced by the effect of streamline curvature. In addition, asymmetric secondary flows were induced in the Reynolds number range above assumed laminar flow regime considered. However, turbulence calculations and grid dependency studies are needed for more accurate computations.

• 동력기계공학회지
• /
• 제5권1호
• /
• pp.50-56
• /
• 2001

Jet pumps are used in a great number of engineering applications. In the present study, jet shapes, mixing chamber shapes, and numerical methods for predicting the performance of an annular-type jet pump are investigated to determine the optimal turbulence model. The flow fields are simulated by solving the momentum and the continuity equations with the standard ${\kappa}-{\epsilon}$ and the RNG ${\kappa}-{\epsilon}$ turbulence models at different Reynolds numbers. After that, they are compared with the corresponding experimental data to determine the optimal model. Next, various calculations are conducted to find an optimal shape using the selected turbulence model. The study shows us that the RNG ${\kappa}-{\epsilon}$ model predicts the performance more exactly, and also shows that the most effective performance can be achieved with $12^{\circ}$ reducing angle and 130mm throat length.

• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제12권1호
• /
• pp.47-55
• /
• 2005

For topological spaces X, Y and the function f : X → Y, it induces a function gr(f) : X → X x Y defined as gr(f)(χ) = (χ, f(χ)), for every χ ∈ X. It deals with some preliminary investigations relating to the behavior of functions and its graph functions. It has also been found that continuous functions are homotopic if and only if their graph functions are homotopic.

• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제10권2호
• /
• pp.133-144
• /
• 2003

The aim of this paper is to prove some common fixed point theorems for the class of compatible maps to larger class of weakly compatible maps without appeal to continuity in Monger spaces and we also give a set of alternative conditions in place of completeness of the space. We improve and extend the results of Dedeic & Sarapa ［A common fixed point theorem for three mappings on Monger spaces. Math. Japon. 34 (1989), no. 6,919-923］ and Rashwan & Hedar ［On common fixed point theorems of compatible mappings in Monger spaces. Demonstratio Math. 31 (1998), no. 3, 537-546］.

• 대한수학회보
• /
• 제30권1호
• /
• pp.109-115
• /
• 1993

In 1940 Eidelheit showed that every homomorphism of a Banach algebra onto the Banach algebra B(X) of all bounded linear operators on a Banach space X is continuous. At about the same time, Gelfand proved that every homomorphism of a commutative Banach algebra into a commutative semi-simple Banach algebra is continuous. In [7] Johnson proved that every homomorphism of a Banach algebra onto non-commutative semi-simple Banach algebra is continuous, and this is still the most important result of this type. In this paper we are concerned with continuity of derivations on commutative Banach algebras and of homomorphisms into commutative Banach algebras. Throughout this paper we suppose that A is a commutative Banach algebra. R will denote the redical of A.

• Structural Engineering and Mechanics
• /
• 제7권6호
• /
• pp.561-573
• /
• 1999

A $C^*$-convergence algorithm for finite element analysis has been proposed by Bigdeli and Kelly (1997) and elements for the first three levels applied to planar elasticity have been defined. The fourth level element for the new family is described in this paper and the rate of convergence for the $C^*$-convergence algorithm is investigated numerically. The new family adds derivatives of displacements as nodal variables and the number of nodes and elements can therefore be kept constant during refinement. A problem exists on interfaces where the derivatives are required to be discontinuous. This problem is addressed for curved boundaries and a procedure is suggested to resolve the excessive interelement continuity which occurs.

• International Journal of CAD/CAM
• /
• 제9권1호
• /
• pp.55-60
• /
• 2010

Quadratic B$\acute{e}$zier curves are important geometric entities in many applications. However, it was often ignored by the literature the fact that a single segment of a quadratic B$\acute{e}$zier curve may fail to fit arbitrary endpoint unit tangent vectors. The purpose of this paper is to provide a solution to this problem, i.e., constructing $G^1$ quadratic B$\acute{e}$zier curves satisfying given endpoint (positions and arbitrary unit tangent vectors) conditions. Examples are given to illustrate the new solution and to perform comparison between the $G^1$ quadratic B$\acute{e}$zier cures and other curve schemes such as the composite geometric Hermite curves and the biarcs.

• 한국환경과학회지
• /
• 제25권9호
• /
• pp.1241-1251
• /
• 2016

A minimum threshold for the signal to noise ratio ($SNR_{min}$) has to be set in the data processing system of wind profiler radar (WPR). The data collection rate and the accuracy of the WPR wind vector depend on the $SNR_{min}$. The WPR at Uljin is operated with an $SNR_{min}$ of 1 dB which is a relatively large threshold. We found that the accuracy and the continuity of the WPR wind vector with height were directly related to the variability of the SNR and vertical gradient of the squared refractive index. We investigated a quantitative method for determining a new $SNR_{min}$ for the WPR at Uljin and it was evaluated with radiosonde data. The accuracy and continuity of the wind vector from an SNR of less than 1 dB, began to decrease at an altitude of 3.5 km. Most of the SNR values were less than -3.5 dB in altitudes higher than 3.5 km. We retrieved high-accuracy wind vectors at altitudes over 3 km where measurements were deficient with an $SNR_{min}$ of 1 dB.