• Journal of the Chungcheong Mathematical Society
• /
• v.20 no.3
• /
• pp.203-210
• /
• 2007

Let X be a hyperbolic region in the complex plane C such that the hyperbolic metrix ${\lambda}_X(w){\mid}dw{\mid}$ exists. Let $R(X)=sup\{{\delta}_X(w):w{\in}X\}$ where ${\delta}_X(w)$ is the euclidean distance from w to ${\partial}X$. Here ${\partial}X$ is the boundary of X. A hyperbolic region X is called a Bloch region if R(X) < ${\infty}$. In this paper, we obtain lower bounds for the hyperbolic metric on Bloch regions in terms of the distance to the boundary.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.2B
• /
• pp.87-96
• /
• 2012

In this paper, we consider a 2-hop relay system where both the relay and destination nodes suffer from the arbitrary number of co-channel interferers. More specifically, assuming that the relay and access channels as well as interference channels are all subject to Rayleigh fading, we derive an exact closed-form expression for outage probability of the amplify-and-forward (AF) relay system, and furthermore compute its upper and lower bounds. Based on these bounds, we derive the upper and lower bounds on the average bit error rate (BER) of the AF relay system. We also confirm the accuracy of our derivation by investigating the performance gap between the performance bounds under consideration and simulation results.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.23 no.5
• /
• pp.1222-1228
• /
• 1998

Most of researchers have tried to find heuristic methods for near-optimal solutions of establishing light paths with minimum number of wavelengths in wavelengh-routed optical networks. In order to provide a performance measure for heuristic approaches, we propose a practical approach for a lower bound of the number of wavelengths which is required to provide full connections in WDM-based optical transport networks. This method is based on a path-flow formulation using K-shortest paths for each connection. Compared with a general link-flow formulation, the proposed method has much lower complexity and so needs much less calcuation tiem while it gives the same results as a general link-flow formulation in some sample networks.

• Geomechanics and Engineering
• /
• v.23 no.1
• /
• pp.15-30
• /
• 2020

The probabilistic bearing capacity of a strip footing placed on the edge of a purely cohesive reinforced soil slope is computed by combining lower bound finite element limit analysis technique with random field method and Monte Carlo simulation technique. To simulate actual field condition, anisotropic random field model of undrained soil shear strength is generated by using the Cholesky-Decomposition method. With the inclusion of a single layer of reinforcement, dimensionless bearing capacity factor, N always increases in both deterministic and probabilistic analysis. As the coefficient of variation of the undrained soil shear strength increases, the mean N value in both unreinforced and reinforced slopes reduces for particular values of correlation length in horizontal and vertical directions. For smaller correlation lengths, the mean N value of unreinforced and reinforced slopes is always lower than the deterministic solutions. However, with the increment in the correlation lengths, this difference reduces and at a higher correlation length, both the deterministic and probabilistic mean values become almost equal. Providing reinforcement under footing subjected to eccentric load is found to be an efficient solution. However, both the deterministic and probabilistic bearing capacity for unreinforced and reinforced slopes reduces with the consideration of loading eccentricity.

• Clinical and Experimental Reproductive Medicine
• /
• v.24 no.3
• /
• pp.385-391
• /
• 1997

The purpose of this study was to examine the effects of anti-sperm antibody (ASA) on the fertilization processes using conventional IVF and ICSI procedure in human and hamster oocytes. In human IVF, we have observed restricted fertilization with sperm testing positive for ASA. ($23{\sim}90%$ IgA, 60-97 % IgG). However, if ICSI was perform in the next IVF cycle with the same patients, we could successfully fertilize the oocytes (37%; p<0.001), thus achieving pregnancy and delivery. When the sperm were cocultured in medium containing ASA, there were binding of ASA to sperm surface. In addition, the mean rate of the acrosomal reaction in an in vitro acrosome reaction test was lower for Ab-bound sperm (43.5%) than for Ab-free sperm group (51.3%, p<0.05). We used human sperm and hamster oocytes to confirm the negative effects of the ASA on fertilization. The sperm and/or oocytes have been expose to medium containing ASA before IVF and ICSI. In this experiment, the ASA was bound to the oocyte and sperm surface. The following results were obtain by using various combinations of ASA free or ASA bound sperm with ASA free or ASA bound oocytes for IVF. When ASA free sperm were inseminate with ASA free and ASA bound hamster oocytes, the fertilization rates are 89.6% and 74.3% respectively. However, when ASA bound human sperm were use the results were 62.5% and 55.6% respectively. These shows the fertilization rate was significantly decreased in both ASA bound and ASA free oocytes when using ASA bound sperm. No difference found when ASA are present on the oocyte surface. When the hamster oocytes was treated by ICSI with ASA free or ASA bound human spermatozoa, no significant difference was found. These results showed that ICSI is the most promising method for couples who fertilization was not possible by conventional IVF because of ASA.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.27 no.3
• /
• pp.145-156
• /
• 2002

Business managers are often required to use LP problems to deal with uncertainty inherent in decision making due to rapid changes in today＇s business environments. Uncertain parameters can be easily formulated in the two-stage stochastic LP problems. However, since solution methods are complex and time-consuming, a common approach has been to use modified formulations to provide upper and lower bounds on the two-stage stochastic LP problem. One approach is to use an expected value problem, which provides upper and lower bounds. Another approach is to use “walt-and-see” problem to provide upper and lower bounds. The objective of this paper is to propose a modified approach of “wait-and-see” problem to provide an upper bound and to compare the relative error of optimal value with various upper and lower bounds. A computing experiment is implemented to show the relative error of optimal value with various upper and lower bounds and computing times.

• Journal of Food Hygiene and Safety
• /
• v.25 no.4
• /
• pp.289-293
• /
• 2010

3-MCPD created in manufacture process was regulated in our country about soy sauce and HVP. The latest paper reported that Bound 3-MCPD is created as intermediate. Germany common risk assesment reported that Bound 3-MCPD must be reduced because Bound 3-MCPD can be created in estimation circle when this is hydrolyzed in human body, but the data about the toxity of Bound 3-MCPD is lack. Therefore, We analysis about 209 items food such as soy sauce, seasoning food and meat-eating manufactured goods using bound 3-MCPD analysis method developed recently. As result of survey, bound 3-MCPD detected in 8 items among 44 traditional sauce (0.02~0.28ppm), 8 of soup 12 items (0.01~0.96ppm), in 22 items of sauce 60 items (0.01~0.55ppm), in 16 items of meat-eating manufactured foods 30 items (0.04~0.18ppm), in 20 items of snack cookies 28 items (0.09~1.43ppm), in 8 in roasted oil foods 10 items (0.04~1.22ppm), in 6 items of peanut processed food 10 items (0.06~0.25ppm), in 1 of vegetable cream 15 items (0.05ppm). Detected level was lower than the result of monitored by other countries.

• Journal of applied mathematics & informatics
• /
• v.33 no.5_6
• /
• pp.627-633
• /
• 2015

In this paper, we generalize the concept of the energy of Seidel matrix S(G) which denoted by S^α(G) and obtain some results related to this matrix. Also, we obtain an upper and lower bound for S^α(G) related to all of graphs with |detS(G)| ≥ (n - 1); n ≥ 3.

• Communications of the Korean Mathematical Society
• /
• v.10 no.2
• /
• pp.461-469
• /
• 1995

Some bounds for anisotropic torsional rigidity with one plane of elastic symmetry perpendicular to the axis of the beam are derived by making use of the isoperimetric inequalities, complementary variational principles, and the maximum principle. Upper and lower bounds are obtained by applying the isoperimetric inequalities. While the upper bound investigated by the variational principles and maximum principle. The analysis is patterned after the work of Payne and Weinbeger [J. Math. Anal. Appl. 2(1961). pp. 210-216].

• Journal of applied mathematics & informatics
• /
• v.27 no.3_4
• /
• pp.943-953
• /
• 2009

In this paper, we give the lower and upper bounds for inverse elements of strictly diagonally dominant seventh-diagonal matrices, and improve the bounds on [SIAM. J. matrix Anal.App1.20(1999)820-837].