In this study, we examined the effectiveness of in vitro fertilization of porcine immature oocytes on the embryo development of blastocysts or hatched blastocysts and the number of cells according to the in vitro fertilization conditions. In the in vitro fertilization of in vitro matured porcine oocytes, there were no significant differences between treatment groups regarding fertilization rate, blastocyst rate, and embryo development of hatched blastocysts according to the storage periods of liquid sperm of 24, 48, and 72 hours. The embryo development rate of hatched blastocysts after the fertilization according to different spermatozoa concentrations (, , and cells/ml) showed the highest rate in the group with a spermatozoa concentration of cells/ml; in particular, this rate was significantly higher than that in the cells/ml group (p<0.05). The total number of blastocysts cells as well as trophectoderms (TE) that developed in each treatment group were also significantly higher in the cells/ml group than in any other groups (p<0.05). In contrast, the embryo development rate of blastocysts according to different co-incubation periods of sperm and oocyte (1, 3, and 6 hr) was high in the 6-hour group; in particular, the rate was significantly higher than that of the I-hour group (p<0.05). Furthermore, the total number of oocytes cells and TEs that developed was significantly higher in the 6-hour group than any other group (p<0.05). In this study, the most effective treatment conditions for porcine embryo development and high cell number were found to be as follows: a sperm storage period of less than 72 hours, a spermatozoa concentration of cells/ml, and a 6-hour co-incubation period for sperm and ooocyte.

In a pretensioned concrete member, the effective prestress is not fully developed in a certain length from the end of the member, which is defined as transfer length. Because of its complex mechanism, previous transfer length models are mostly empirical and provide very different results. In this study, the Adaptive Neuro-Fuzzy Inference System(ANFIS) was introduced to estimate the transfer lengths of pretensioned concrete members. A total of 209 experimental data has been used to train ANFIS, and the trained ANFIS algorithm estimated the transfer lengths of test specimens very accurately.

The volume expansion of corroded steel reinforcement produces tensile stress on the surrounding concrete, which causes splitting cracking of concrete cover, and deteriorates the service ability and durability of reinforced concrete(RC) members. In addition, since the steel corrosion induces bond strength degradation between steel bar and concrete, the structural performance of RC members can be deteriorated significantly. In this study, the theoretical study was performed to probe the mechanism of the bond strength reduction due to steel corrosion. The bond strength between corroded steel bar and concrete was calculated by mathematically formulating the expansion pressure of corroded steel reinforcement. The proposed model was verified by comparing with the existing test results, and it showed that the proposed model estimate the bond strength reduction of corroded RC elements very closely.