• Journal of Korea Multimedia Society
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• v.11 no.12
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• pp.1688-1696
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• 2008

We propose a hierarchical service management method using Bloom filters for large MANETs. In this paper, a MANET is comprised of logical grid hierarchy, and each mobile node within the lowest service region multicasts the Attenuated Bloom Filter (ABF) for services itself to other nodes within the region. To advertise and discovery a service efficiently, the server node of the lowest server region sends the Summary Bloom Filter (SBF) for the ABFs to the server node of upper server region. Each upper server has the set of SBFs for lower vicinity service regions. The traffic load of the proposed method is evaluated by an analytical model, and is compared with that of two alternative advertisement solutions: complete advertisement and no advertisement. As a result, we identify that the traffic load of the proposed method is much lower than that of two alternative advertisement solutions.

• Journal of applied mathematics & informatics
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• v.28 no.1_2
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• pp.49-58
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• 2010

In the present article we consider the diffusive Nicholson's blowflies equation with nonlocal delay incorporated into an integral convolution over all the past time and the whole infinite spatial domain $\mathbb{R}$. When the kernel function takes a special function, we construct a pair of lower and upper solutions of the corresponding travelling wave equation and obtain the existence of travelling fronts according to the existence result of travelling wave front solutions for reaction diffusion systems with nonlocal delays developed by Wang, Li and Ruan (J. Differential Equations, 222(2006), 185-232).

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.10a
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• pp.60-64
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• 1997

In a fuzzy relation equation R=U=T, we find the bounde by U* and U* of the equation where U* is lower bound and U* is upper bound.

• Journal of the Korean Geotechnical Society
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• v.27 no.5
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• pp.45-59
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• 2011

This study introduces the diagrammatic Upper and Lower Bound (UB and LB) methods theoretically in order to derive the bearing capacity factor, $N_c$ in undrained clay and to compare with Prandtl's exact solution (1921). As a result of the theoretical study, an exact solution comes out when the UB and LB solutions are the same. In addition, the finite element analyses show that the failure loads approach to the bearing capacity factor of 5.14. Results of the FEA significantly depend on the finite element type, a number of elements, and a number of increments. From this study the exact solution defines that solutions from UB and LB are the same. However, this situation is very difficult to process, so we can confirm the exact solution as a range between UB and LB solutions.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.2
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• pp.458-466
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• 1993

Natural convection in trapezoidal sections of cavity was numerically investigated using a Finite Volume Method. Temperatures of the upper inclined and lower horizontal walls are constant, with vertical side walls being insulated. When the top wall is hotter than the bottom one, a single cell of stratified flow field is obtained and heat transfer occurs only by conduction. For the colder top wall, bifurcation solutions are obtained for the higher Rayleigh numbers, while unique solutions for lower values. Flow structure is strongly dependent on the configuration and the Rayleigh number.

• Structural Engineering and Mechanics
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• v.53 no.1
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• pp.27-40
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• 2015

The rational analytical solutions are presented for functionally graded beams subjected to arbitrary tractions on the upper and lower surfaces. The Young's modulus is assumed to vary exponentially along the thickness direction while the Poisson's ratio keeps unaltered. Within the framework of symplectic elasticity, zero eigensolutions along with general eigensolutions are investigated to derive the homogeneous solutions of functionally graded beams with no body force and traction-free lateral surfaces. Zero eigensolutions are proved to compose the basic solutions of the Saint-Venant problem, while general eigensolutions which vary exponentially with the axial coordinate have a significant influence on the local behavior. The complete elasticity solutions presented here include homogeneous solutions and particular solutions which satisfy the loading conditions on the lateral surfaces. Numerical examples are considered and compared with established results, illustrating the effects of material inhomogeneity on the localized stress distributions.

• Kyungpook Mathematical Journal
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• v.59 no.1
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• pp.191-202
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• 2019

The aim of this paper is to develop a monotone iterative technique by introducing upper and lower solutions to Riemann-Liouville fractional differential equations with deviating arguments and integral boundary conditions. As an application of this technique, existence and uniqueness results are obtained.

• Journal of the KSME
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• v.16 no.1
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• pp.49-53
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• 1976

Groundwater flow in a two-layer aquifer is studied theoretically and experimentally. Nonlinear differential equations are independently linearized for the upper and the lower layer, and approximate solutions are obtained. Fine sands and coarse sands are used in experiments. For steady flow, theoretical solutions agrees excellently with experimental results For unsteady flow, however, agreement is not so good, because the experimental conditions do not match with theoretical assumptions.

• Steel and Composite Structures
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• v.17 no.4
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• pp.535-548
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• 2014

In this paper, the exact closed-form solutions for torsional analysis of heterogeneous magnetostrictive circular cylinder are derived. The cylinder is subjected to the action of a magnetic field produced by a constant longitudinal current density. It is also acted upon by a particular kind of shearing stress at its upper base. The rigidity of the cylinder is graded through its axial direction from one material at the lower base to another material at the upper base. The distributions of circumferential displacement and shear stresses are presented through the radial and axial directions of the cylinder. The influence of the magnetostrictive parameter is discussed. The effects of additional parameters are investigated.

• Journal of the Korean Mathematical Society
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• v.37 no.5
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• pp.823-833
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• 2000

In this paper, we develop the method of quasilinearization comvined with the methos of upper and lower solutions for singular second order boundary value problems in weighted spaces. The sequences constructed converge uniformly and monotonically to the unique of the second singular order boundary value problem. Further we prove the rate of convergence is quadratic.