• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.717-723
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• 2020

Determination of local tie vectors between the space geodetic techniques such as VLBI (Very Long Baseline Interferometer), SLR (Satellite Laser Ranging), DORIS (Doppler Orbit determination and Radiopositioning Integrated on Satellite), GNSS (Global Navigation Satellite System) is essential for combination of ITRF (International Terrestrial Reference Frame). Therefore, it is required to compute IVP (Invariant Point) position of each space geodetic technique with high accuracy. In this study, we have computed Sejong VLBI IVP position by using updated mathematical model for adjustment computation so that the improvement on efficiency and reliability in computation are obtained. The measurements used for this study are the coordinates of reflective targets on the VLBI antenna and their accuracies are set to 1.5 mm for each component. The results show that the position of VLBI IVP together with its standard deviation is successfully estimated when they are compared with those of the results from previous study. However, it is notable that additional terrestrial surveying should be performed so that realistic measurement errors are incorporated in the adjustment computation process.

• Journal of Embryo Transfer
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• v.15 no.3
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• pp.255-261
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• 2000

The objective of this study was to improve the efficiency of bovine embryo transfer by transferring of Hanwoo embryos into Hanwoo or Holstein recipients. The cryopreserved or fresh in vitro produced(IVP) embryos were transferred into uterine horn contralaterally or ipsilaterally to the corpus luteum. The recipients were inseminated by artificially on the next day of estrus. The pregnancy was diagnosed by rectal palpation at 60∼90 days after transfer of the embryos. The pregnancy rate by transfer of one or two embryos was 78%(7/9) and 74%(31/42), respectively. The pregnancy rates according to the grade of corpus lutea of recipients was 75% (20/27) and 82.0%(18/22) at the grade of A and B, respectively. Ten(67.0%) of 15 Holstein recipients transferred with IVP Hanwoo embryos and 5(42.0%) of 12 Holstein recipients transferred with frozen IVP Hanwoo embryos were pregnant. The single and twin calving ratio in Hanwoos was 77.0%(10/13) and 23.0%(3.13) in the recipients transferred with IVP embryos and 64.0%(7/10) and 27.0%(3/10) in the recipients transferred with frozen IVP embryos, respectively. Twenty-four pregnant cows following transfer of IVP embryos, 21(88.0%) calved the normal calves, and 2(8.3%) aborted. When the frozen IVP embryos were transferred, 16 pregnant cows calved 14(88.0%) normal calves and 2(13.0%) aborted. In conclusion, when one or two IVP bovine embryos were transferred into recipients, the A and B grade of corpus luteum resulted in high pregnancy rates. For the production of twin calves, transfer of the IVP or frozen IVP embryos could be suitable.

• Educational Technology International
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• v.23 no.2
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• pp.129-155
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• 2022

This study sought to design and develop an interactive video player (IVP) capable of promoting student engagement through the use of online video content. We designed features built upon interactive, constructive, active, passive (ICAP), and crowd learning frameworks. In the development stage of this study, we integrated numerous interactive features into the IVP intended to help learners shift from passive to interactive learning activities. We then explored the effectiveness and usability of the developed IVP by conducting an experiment in which we evaluated students' exam scores after using either our IVP or a conventional video player. There were 158 college students who participated in the study; 76 students in the treatment group used the IVP and 82 students in the control group used a conventional video player. Results indicate that the participants in the experiment group demonstrated better achievement than the participants in the control group. We further discuss the implications of this study based on an additional survey that was administered to disclose how usable the participants perceived the IVP to be.

• Journal of Animal Reproduction and Biotechnology
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• v.38 no.2
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• pp.47-53
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• 2023

Despite numerous advances in in-vitro embryo production (IVP), many documented factors have been shown to influence the development of mammalian preimplantation embryos and the success of IVP. In this sense, elevated levels of reactive oxygen species (ROS) correlate with poor outcomes in assisted reproductive technologies (ART) due to oxidative stress (OS), which results from an imbalance between ROS production and neutralization. Indeed, excessive production of ROS compromises the structural and functional integrity of gametes and embryos both in vivo and in vitro. In particular, OS damages proteins, lipids, and DNA and accelerates cell apoptosis. Several in-vivo and in-vitro studies report an improvement in qualityrelevant parameters after the use of various antioxidants. In this review, we focus on OS and the source of free radicals and their effects on oocytes, sperm, and the embryo during IVP. In addition, antioxidants and their important role in IVP, supplementation during oocyte in vitro maturation (IVM), in vitro culture (IVC), and semen extenders were discussed. Nevertheless, various methods for determining the level of ROS in germ cells have been briefly described. Still, it is crucial to develop standardized antioxidant supplement systems to improve overall IVP success. Further studies should explore the safety, efficacy, mechanism of action, and combination of different antioxidants to improve IVP outcomes.

• Journal of Biomedical Engineering Research
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• v.18 no.1
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• pp.25-36
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• 1997

To regulate cardiac output of the Total Artificial Heart(TAH) physiologically, the hemodynamic information must be toed back to the controller. So far, our group has developed an automatic cardiac output control algorithm using the motor current waveform, It is, however difficult to detect the preload level such as a filling status of ventricular inflow and the variation of atrial pressures within normal physiologic range(0-15 mmHg) by analyzing the motor current which simultaneously reflects the afterload effect. On the other hin4 the interventricular volume pressure(IVP) which is not influenced by arterload but by preload is a good information source for the estimation of preload states. In order to find the relationship between preload and IVP waveform, we set up the artificial heart system on the Donovan type mock circulatory system and measured the IVP waveform, right and left atrial pressures, inflow and outflow waveforms and the signals represented the information of moving actuator's position. We shows the feasibility of estimating the hemodynamic changes of inflow by using IVP waveform. fife found that the negative peak value of IVP waveform is linearly related to atrial pressures. And we also found that we could use the time to reach the negative peak in IVP waveform, the time to open outflow valve, the area enclosed IVP waveform as unfu parameters to estimate blood filling volume of diastole ventricle. The suggested method has advantages of avoiding thrombogenesis, bacterial niche formation and increasing longterm reliability of sensor by avoiding direct contact to blood.

• Journal of Embryo Transfer
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• v.16 no.1
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• pp.29-34
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• 2001

To investigate the effect of co-transfer of trophoblastic vesicle (TV) with frozen-thawed in vitro Produced (IVP) bovine embryo on pregnancy rate, IVP blastocysts were transferred to synchronized recipients. Elongated blastocysts were recovered at Day 13 to 15, and dissected more than 4 pieces to removed the embryonic disc. Throphoblastic fragments were cultured for 48 hours to make throphoblastic vesicles (TVs). TVs were cryopreserved in ethylene glycol or vitrification solution and frozen-thawed TVs were co-transferred to recipients with frozen-thawed IVP embryos. 1 The recovery rate of elongated blastocyst on Day 13 to 15 was 22.5% (18/80) and the size of recovered elongated blastocysts was 0.2∼5.0mm. 2. Eighteen elongated blastocysts were dissected into 88 pieces and 61.4% of those pieces were formed to TV (54/88) 3. The viability of frozen-thawed TV in ethylene glycol was higher than in vitrified solution (92.8% vs. 68.8%) 4. The pregnancy rate in co-transfer with frozen-thawed TV and IVP blastocyst was better than transfer only IVP blastocysts (50.0% vs. 23.1%).

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.8-17
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• 2002

There have been intensive attempts to establish reliable methods far in vitro production (IVP) methods for of porcine embryos. Although a great deal of progress has been made, our current IVP systems still need to be improved. In this review, we focused on studies about in vitro maturation and fertilization (IVM-IVF) of porcine oocytes and their in vitro culture (IVC), especially on an excellent piglets production system using modified IVP system producing porcine blastocysts with high Quality.

• Journal of Embryo Transfer
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• v.30 no.3
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• pp.149-159
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• 2015

This study was designed to know the possibility in repeat uses of elite donor cows for getting mass production of OPU-derived embryo production (OPU-IVP). Ultrasound transvaginal ovum pick-up (OPU) performed in 6 Korean native cows was aged 4 to 10 years old. The aspiration of immature oocytes for OPU derived embryo was carried out 2 times per week, and OPU-IVP of $1^{st}$ period was carried out 22~48 sessions from each donors. And the break time for OPU-IVP of $2^{nd}$ period after $1^{st}$ OPU from each donors were 2~25 months. The OPU-IVP of $2^{nd}$ period each donors conducted total 15~65 times for 2~8 months by an ultrasonographic, was guided follicular aspiration system. The average numbers of collected oocytes, grade 1 + grade 2(G1+G2) oocytes and cleavage embryo from $1^{st}$ period OPU-IVP were significantly differences between donors (p<0.05). Total collected oocytes of donor D were significantly higher compared with donors of A, B, C, E and F (average 17.0 per session vs. 11.2, 10.1, 8.5, 10.2 and 9.6; p<0.05) and also oocytes of G1+G2 were significantly higher compared with r A and D and subsequently to donors of B, C, E and F (average 7.9 and 8.5 per session vs. 5.0, 2.7, 6.0 and 1.6; p<0.05). Cleavage rate of donor D was significantly higher compared with donors of A, B, C, E and F (average 13.1 per session vs. 10.1, 9.1, 6.9, 8.9 and 6.7; p<0.05). The average numbers of OPU-IVP for $1^{st}$ period was significantly higher from donors of B, D and E than those from donors of A, C and F (average 6.5, 7.1 and 6.5 per session vs. 3.5, 4.2 and 2.8; p<0.05). The possibility investigation of $2^{nd}$ OPU-IVP was carried out after 2~25 months rest periods from $1^{st}$ period OPU session. Total average numbers of collected oocytes, cleavages and blastocyst development rates were significantly higher from $1^{st}$ period OPU compared with $2^{nd}$ period one (p<0.05). The OPU-IVP efficiency by break for more embryo production from elite cow was analysis comparing without rest of donor A, under 6 months rest period as B and over 6 months rest period as C and then the average numbers of collected oocytes, cleavages and blastocysts were significantly higher from A group (11.8, 9.5 and 5.2 per session) than those from B and C groups (7.9, 6.2 and 2.6 vs. 9.2, 7.5 and 3.9, p<0.05), and also C group was significantly higher than B group. In conclusion, $1^{st}$ period OPU-IVP was more efficient compared with $2^{nd}$ period repeated uses of donor, and the break times for additional production of embryo on donor were needed more than over 6 months after $1^{st}$ period OPU-IVP. This repeating uses of elite donor cows given more emphasis for getting the opportunity on mass production of elite cow OPU-IVP embryo should be increased G1+G2 possibility of genetic improvement of livestock within short period.

• Reproductive and Developmental Biology
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• v.39 no.2
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• pp.29-36
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• 2015

Pigs are considered an ideal source of human disease model due to their physiological similarities to humans. However, the low efficiency of in vitro embryo production (IVP) is still a major barrier in the production of pig offspring with gene manipulation. Despite ongoing advances in the associated technologies, the developmental capacity of IVP pig embryos is still lower than that of their in vivo counterparts, as well as IVP embryos of other species (e.g., cattle and mice). The efficiency of IVP can be influenced by many factors that affect various critical steps in the process. The previous relevant reviews have focused on the in vitro maturation system, in vitro culture conditions, in vitro fertilization medium, issues with polyspermy, the utilized technologies, etc. In this review, we concentrate on factors that have not been fully detailed in prior reviews, such as the oocyte morphology, oocyte recovery methods, denuding procedures, first polar body morphology and embryo quality.

• Journal of The Korean Astronomical Society
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• v.51 no.5
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• pp.143-153
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• 2018

We present the first results of the invariant point (IVP) coordinates of the KVN Ulsan and Tamna radio telescopes. To determine the IVP coordinates in the geocentric frame (ITRF2014), a coordinate transformation method from the local frame, in which it is possible to survey using the optical instrument, to the geocentric frame was adopted. The least-square circles are fitted in three dimensions using the Gauss-Newton method to determine the azimuth and elevation axes in the local frame. The IVP in the local frame is defined as the mean value of the intersection points of the azimuth axis and the orthogonal vector between the azimuth and elevation axes. The geocentric coordinates of the IVP are determined by obtaining the seven transformation parameters between the local frame and the east-north-up (ENU) geodetic frame. The axis-offset between the azimuth and elevation axes is also estimated. To validate the results, the variation of coordinates of the GNSS station installed at KVN Ulsan was compared to the movement of the IVP coordinates over 9 months, showing good agreement in both magnitude and direction. This result will provide an important basis for geodetic and astrometric applications.