• Journal of the Chungcheong Mathematical Society
• /
• v.16 no.1
• /
• pp.49-60
• /
• 2003

In this note, we introduce the concept of the extremal length of a curve family in the complex plane and apply the extremal length to the boundary behavior of analytic functions. We consider some geometric applications of extremal length and establish applications connected with the logarithmic capacity.

• Journal of the Chungcheong Mathematical Society
• /
• v.23 no.3
• /
• pp.463-470
• /
• 2010

If P(f, r) is the set of endpoints of radii which have length greater than or equal to r > 0 under a conformal mapping f of the unit disc. Then for large r, the logarithmic capacity of P(f, r), $\frac{1}{\sqrt[2]{r}}{\leq}cap(P(f,r)){\leq}\frac{k}{\sqrt{r}}$. Where k is the positive constant.

• Journal of applied mathematics & informatics
• /
• v.20 no.1_2
• /
• pp.647-655
• /
• 2006

We consider the applications of modulus to the boundary behavior of meromorphic functions in connection with the singularities. The proofs are based on the method of modulus. The relations between the moduli and the logarithmic capacities shall be introduced and we have shown that the conformal capacity is related to the modulus.

• Journal of applied mathematics & informatics
• /
• v.15 no.1_2
• /
• pp.495-502
• /
• 2004

We consider the applications of extremal length to the boundary behavior of analytic functions and derive a theorem in connection with the capacity. This theorem applies the extremal length to the analytic functions defined on the domain with a number of holes. So it shows us the usefulness of the method of extremal length.

• Journal of the Korean Society for Heat Treatment
• /
• v.11 no.1
• /
• pp.27-34
• /
• 1998

Effects of different heat treatments on microstructure and damping capacity of Cu-55%Mn alloy were investigated to find an optimum heat treatment condition for a maximum damping capacity. The alloy showed the high level of damping capacity in case of the aging at 375 and $400^{\circ}C$. This is ascribed to the FCC${\rightarrow}$FCT martensitic transformation and microstructural changes from mottled to tweed band type. The damping capacity had a maximum value of 0.33 in logarithmic decrement when the alloy was aged at $375^{\circ}C$ for 14 hours followed by 20 times of thermal cycling between room temperature and $250^{\circ}C$. The refinement of tweed structure by thermal cycling is thought to be responsible for the highest damping capacity.

• ETRI Journal
• /
• v.30 no.3
• /
• pp.483-485
• /
• 2008

A micro-sensor network is comprised of a large number of small sensors with limited memory capacity. Current key-establishment schemes for symmetric encryption require too much memory for micro-sensor networks on a large scale. In this paper, we propose a memory-efficient hypercube key establishment scheme that only requires logarithmic memory overhead.

• Honam Mathematical Journal
• /
• v.28 no.2
• /
• pp.213-219
• /
• 2006

We will investigate whether Jucha's result on the Zalcman type domain can be extended to an arbitrary domain in C.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.1
• /
• pp.75-80
• /
• 2016

Numerical modeling based on the finite difference method has been widely used with improved computer technology. However, high-capacity computing resources are required for this technique. To overcome this limitation, we propose an algorithm the employs a logarithmic grid in conjunction with the expanding domain method. The proposed algorithm was verified through comparison with numerical results obtained with a conventional method. The results confirmed that our algorithm can improve computational efficiency.

• Earthquakes and Structures
• /
• v.3 no.6
• /
• pp.821-838
• /
• 2012

This paper proposes a new three-layer pillar-type hysteretic damper system for residential houses. The proposed vibration control system has braces, upper and lower frames and a damper unit including hysteretic dampers. The proposed vibration control system supplements the weaknesses of the previously proposed post-tensioning vibration control system in the damping efficiency and cumbersomeness of introducing a post-tension. The structural variables employed in the damper design are the stiffness ratio ${\kappa}$, the ductility ratio ${\mu}_a$, and the ratio ${\beta}$ of the damper's shear force to the maximum resistance. The hysteretic dampers are designed so that they exhibit the targeted damping capacity at a specified response amplitude. Element tests of hysteretic dampers are carried out to examine the mechanical property and to compare its restoring-force characteristic with that of the analytical model. Analytical studies using an equivalent linearization method and time-history response analysis are performed to investigate the damping performance of the proposed vibration control system. Free vibration tests using a full-scale model are conducted in order to verify the damping capacity and reliability of the proposed vibration control system. In this paper, the damping capacity of the proposed system is estimated by the logarithmic decrement method for the response amplitudes. The accuracy of the analytical models is evaluated through the comparison of the test results with those of analytical studies.

• Journal of Communications and Networks
• /
• v.6 no.4
• /
• pp.352-361
• /
• 2004

In this paper, we study how to achieve the maximum capacity under delay constraints for large mobile wireless networks. We develop a systematic methodology for studying this problem in the asymptotic region when the number of nodes n in the network is large. We first identify a number of key parameters for a large class of scheduling schemes, and investigate the inherent tradeoffs among the capacity, the delay, and these scheduling parameters. Based on these inherent tradeoffs, we are able to compute the upper bound on the maximum per-node capacity of a large mobile wireless network under given delay constraints. Further, in the process of proving the upper bound, we are able to identify the optimal values of the key scheduling parameters. Knowing these optimal values, we can then develop scheduling schemes that achieve the upper bound up to some logarithmic factor, which suggests that our upper bound is fairly tight. We have applied this methodology to both the i.i.d. mobility model and the random way-point mobility model. In both cases, our methodology allows us to develop new scheduling schemes that can achieve larger capacity than previous proposals under the same delay constraints. In particular, for the i.i.d. mobility model, our scheme can achieve (n-1/3/log3/2 n) per-node capacity with constant delay. This demonstrates that, under the i.i.d. mobility model, mobility increases the capacity even with constant delays. Our methodology can also be extended to incorporate additional scheduling constraints.