• Geophysics and Geophysical Exploration
• /
• v.4 no.3
• /
• pp.70-79
• /
• 2001

The integral equation method is a powerful tool for numerical electromagnetic modeling. But the difficulty of this technique is the size of the linear equations, which demands excessive memory and calculation time to invert. This limitation of the integral equation method becomes critical in inverse problem. The conventional Born approximation, where the electric field in the anomalous body is approximated by the background field, is very rapid and easy to compute. However, the technique is inaccurate when the conductivity contrast between the body and the background medium is large. Quasi-linear, quasi-analytical and extended Born approximations are novel approaches to 3-D EM modeling based on the linearization of the integral equations for scattered EM field. These approximation methods are much less time consuming than full integral equation method and more accurate than conventional Born approximation. They we, however, still approximate methods for 3-D EM modeling. Iterative series methods such as modified Born, quasi-linear and quasi-analytical can be used to increase the accuracy of various approximation methods. Comparisons of numerical performance against a full integral equation and various approximation codes show that the iterative series methods are very accurate and almost always converge. Furthermore, they are very fast and easy to implement on a computer. In this study, extended Born series method is developed and it shows more accurate result than that of other series methods. Therefore, Iterative series methods, including extended Born series, open principally new possibilities for fast and accurate 3-D EM modeling and inversion.

• Neonatal Medicine
• /
• v.18 no.2
• /
• pp.197-203
• /
• 2011

Purpose: The purpose of this study is to compare perinatal outcomes between in vitro fertilization (IVF) twins and naturally conceived twins born to women aged 35 years or older and to provide basic information for taking care of IVF twins born to women aged 35 years or older. Methods: We reviewed the records of perinatal and neonatal outcomes in 288 IVF twins and 220 naturally conceived twins born to women aged 35 years or older between January 2001 and December 2010 at CHA Bundang Medical Center. Results: No difference was observed in the maternal ages of mothers giving birth to IVF twins and those giving birth to naturally conceived twins. Gestational ages and birth weights of IVF twins were not different from those of naturally conceived twins. Various perinatal outcomes, including gestational diabetes mellitus, pregnancy-induced hypertension, placenta previa, premature amniotic membrane rupture, and need for a Cesarean section did not differ between the 2 groups. However, the 1-min and 5-min Apgar scores (P=0.019 and P=0.045, respectively) were different between the 2 groups. The incidence of early-onset sepsis was lower in the IVF twins than in the naturally conceived twins (P=0.02). However, the 2 groups did not show any difference in the incidence of respiratory distress syndrome, bronchopulmonary dysplasia, patent ductus arteriosus, necrotizing enterocolitis, intraventricular hemorrhage, and other congenital anomalies. Conclusion: The perinatal outcomes in IVF twins born to women aged 35 years or older were not significantly different from those of naturally conceived twins.

• Korean Journal of Animal Reproduction
• /
• v.24 no.2
• /
• pp.171-178
• /
• 2000

To improve the pig farm management and efficiency of swine industry by inducing the farrowing to day-time from night, In the first experiment, reproduction records of purebred and crossbred pigs were collected and analyzed to estimate the $\varepsilon$ ffec 잉 of factors affecting day and night farrowing. The general linear model was used to estimate the least square means of the factors affecting various reproductive characteristics. And also, chi-square tests were used to examine the independence of the reproductive traits and environmental factors using the SAS (1992). The comparisons between pure and crossbred pigs for total number born, percentage of number born alive, gestation length, time length for farrowing were determined. The results indicated that the gestation length of crossbred (115.11 d) was slightly longer than that of purebred (114.89 d, p＜0.05). For the seasonal effects on total number born, the largest was found in spring and no differences were found among summer, fall and winter. The average gestation length was 1 day longer in spring and winter than in summer and fall. The total number born and number born alive were smaller in first, second, and greater or equal to sixth parity than other parities. And also, the percentage of no. born alive was least in greater or equal to sixth parity. For the effect of mating methods, natural and artificial insemination, on total number born and number born alive, no differences between the two methods were found. However, the percentage of number born alive for natural mating was 98.06% and was higher than artificial insemination(93.75%). The time length for farrowing was I hour were found for the 6 hrs of farrowing time. In general situation of pig farms, day-time farrowing was 34.8% and night farrowing was 65.2%, indicating that night farrowing was almost double of the night farrowing.

• ANNALS OF ANIMAL RESOURCE SCIENCES
• /
• v.29 no.4
• /
• pp.158-165
• /
• 2018

The present study was undertaken to investigate the reproductive performance of the female breeding pigs after artificial insemination (AI) using the frozen boar semen imported from Canada, thereby finding insights into improving the efficiency of AI using the frozen semen (FSAI). Analyzed in the present study were the records of a total of 626 FSAI in a great grandparent (GGP) farm beginning from May through November of the year of 2016 (Farm A) and 2,024 FSAI beginning from 2015 through 2017 from a second GGP farm (Farm B). Both the total number of piglets born (TNB) and the number born alive (NBA) were greater during May than during September within FSAI (p<0.05) in Farm A (p<0.01 for the effect of the month). In Farm B, no difference was detected between the years in any of the farrowing rate, TNB, and NBA. When the records from Farm A and Farm B were pooled, the farrowing rate was greater for Farm A vs. Farm B (p<0.01), with no difference between the two farms in TNB and NBA. Moreover, TNB and NBA were less for FSAI than for AI using the liquid semen (LSAI; $10.9{\pm}0.3$ vs. $13.4{\pm}0.1$ and $10.0{\pm}0.3$ vs. $12.0{\pm}0.1$ piglets, respectively, for FSAI vs. LSAI in TNB and NBA, respectively; p<0.01). In conclusion, these results suggest that the reproduction efficiency for FSAI, which is lower than that for LSAI, could be improved by selecting an optimal period of the year for the use of the former.

• Korean Journal of Animal Reproduction
• /
• v.25 no.3
• /
• pp.227-230
• /
• 2001

To know and apply the factors affecting calf's gender may increase our competitiveness of Hanwoo industry. Thus, this study was carried out to analyse the effect of expected factors on calf's gender and to make an alternative idea for desired calf's gender. Gender of calves born by AI was not affected by AI year and cow parity, but significantly affected by sire and farm. Therefore, to obtain calves' gender that we want, both selecting optimum sire for AI and providing optimum feeding environment for cow should be required.

• Journal of Embryo Transfer
• /
• v.17 no.1
• /
• pp.7-12
• /
• 2002

This study was carried out to investigate the possibility of porcine artificial insemination (A·I) on fertilizing capacity using intrauterine inseminator (IUI) method and conventional A·I (CAI) method. Number of sows used in this study was 15 far IUI and 59 fur (CAI), respectively. The results obtained are as fellows: 1 . The frozen and liquid semen used for A·I showed the higher farrowing rate in liquid semen (86.4%) than frozen semen (67%). Number of pigs born per semen type showed the higher values of number of piglets with no statistical significance using frozen semen (9.7) than liquid semen (9.3). 2. The farrowing rate per parity was highest in the 3∼5th parities (100%), f311owe4 by 0∼ 2th parities (60%), and was the smallest in 6 ∼ 10th parities (25%). Number of pigs born per litter was highest in 0∼2th parities (11.3), followed by 3 ∼ 5th parities (9.2) and lowest in 6∼ 10th parities. In the number of pigs bort per litter, the sow s in the high parities delivered lower number of piglets than those in low parities with no significant difference. These results indicated that fertilizing capacity could be improved by using IUI method.

• Journal of Family Relations
• /
• v.21 no.2
• /
• pp.129-147
• /
• 2016

Objective: This study examined the role of siblings with respect to living arrangements between married children and their parents. Previous studies have rarely considered the possibility that family context such as siblings may be associated with intergenerational residential proximity. Method: Using data from first wave of the Korean Longitudinal Study of Ageing (2006), I investigated if, among married children, their sibling characteristics may be associated with the probability of their coresiding with the parent(s), living nearby (within a 30-minute distance from parent(s) by public transportation), or living further away. Specifically, the total numbers of sisters and brothers, the numbers of siblings coresiding with the parent(s) and living nearby, their relative position in the sibling network (first-born son, later-born son, first-born daughter, later-born daughter), and sibship existence and gender configurations (only child, son with brother(s) only, son with sister(s) only, son with both brother(s) and sister(s), daughter with brother(s) only, daughter with sister(s) only, daughter with both brother(s) and sister(s)) were evaluated in the study. For data analysis, multinomial logit models with robust standard errors were estimated using the Stata mlogit procedure. Results: Results suggest that the probability of a married child living together with the parent(s), relative to living close by, was significantly higher the more sisters he or she has. Being a son, especially first-born son, was associated with a higher probability of intergenerational coresidence compared to near residence, respectively. Also, the numbers of siblings coresiding with the parent(s) and living in close proximity were linked to a higher risk of intergenerational coresidence and near residence. Supplementary analyses revealed that the last finding was held over and above the total number of siblings, their relative position in the sibling network, as well as sibling existence and gender configurations. Conclusion: Overall, the study findings indicate that sibling characteristics have significant impacts on intergenerational living arrangement. The influence of traditional patrilineal norm of intergenerational coresidence and a trend towards modified extended family have emerged when siblings characteristics are taken into consideration as determinants of intergenerational living arrangement.

• Korean Journal of Animal Reproduction
• /
• v.26 no.2
• /
• pp.111-117
• /
• 2002

This study was carried out to investigate the effects of frozen boar semen on reproductive performance in swine artificial insemination (AI). Many factors, which were breeds, time of insemination, sperm concentration per dose, farm and year were investigated to improve reproductive performance efficiency. Boars were raised at Swine Artificial Insemination Center in National Livestock Research Institute, Sunghwan, Chungnam, Korea. This experiment was carried out from 1995 to 2000. There were no differences in swine AI with frozen boar semen using 5$m\ell$ maxi-straw among 3 breeds (Landrace, Yorkshire, Duroc), 2 or 3 times insemination per estrus, and 3 different sperm numbers of 3.0, 4.0, and 5.0$\times$10$^{9}$ per dose of insemination. However, non-return rate and litter size of sows inseminated with frozen boar semen of commercial farms were different according to farm management system and inseminator's skill. Conception rate, farrowing rate and number of pigs born alive per litter by artificial insemination with frozen boar semen (5$m\ell$ maxi-straw) from 1995 to 1999 was 68.3~74.6%, 61.7~67.6% and 8.1~8.7 heads.

• Clinical and Experimental Pediatrics
• /
• v.46 no.3
• /
• pp.224-229
• /
• 2003

Purpose : To examine various neonatal outcomes and perinatal factors resulting from assisted reproduction compared to that of spontaneous conception. Methods : This is a retrospective study. The control cases were all twins of spontaneous conception born between periods from January 1995 to June 2000. The study cases were identified from twins conceived by assisted reproduction in the same time peried. A total of 460 sets of twins consisted of 250 twins of spontaneous conception and 156 twins of assisted reproduction were studied. The primary outcomes were neonatal morbidity and mortality and the secondary outcomes were perinatal factors including number, length and cost of hospitalization for the delivery. Results : No differences were seen in various neonatal factors including gestational age, birth weight and incidences of respiratory distress syndrome, patent ductus arteriosus, necrotizing enterocolitis, hyperbilirubinemia, sepsis, intraventricular hemorrhage and the length of hospitalizations. Lower one minute and five minute Apgar scores and frequently encountered electrolyte abnormalities were observed in neonates of assisted reproduction. In general, the second twin of assisted reproduction had increased incidences of respiratory distress syndrome, sepsis and necrotizing enterocolitis than the first twin. Increased frequencies of preterm labor, hospitalization and elective cesarean section were seen among mothers who underwent artifical conception. However, overall hospital costs in terms of mothers hospitalization for the delivery and neonates hospitalization did not show differences. Conclusion : Assisted reproduction twins had similar neonatal morbidities, mortalities and perinatal morbidities compared to those born by spontaneous conception.

• Journal of Korean Society of Archives and Records Management
• /
• v.17 no.4
• /
• pp.87-107
• /
• 2017

Because of the creation and transfer of born-digital records, file unit-based record description practices have changed fundamentally. In this study, we analyzed the archival description practices of The National Archives (TNA) to maintain intellectual control in the digital records management environment and to support the access to records of users. TNA has created an archival description based on ISAD(G) but, for describing born-digital records, it changed the guideline for descriptive cataloging practices. As the method of ISAD(G) cannot adhere to born-digital records, the next-generation descriptive standard, Records in Contexts (RiC), is still being developed by ICA. In addition to international efforts, we need to build an archival description system that fits our environment, especially because since the year 2000, TNA's online cataloging system has changed and ISAD(G) has been modified in this process. This study also proposed continuous monitoring of digital archival descriptions, provides an integrated approach to analog records and digital content and strengthens experimentation and cooperation toward an uncertain digital future.