• 한국산업정보학회논문지
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• 제11권2호
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• pp.9-17
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• 2006

차등 인터넷 서비스를 효과적으로 운영하는 접근법에 대한 연구가 최근에 활발히 진행되고 있다. 인터넷 이용자와 공급자(ISP) 각각의 사회적 편익의 변화에 따른 대역폭 시장 참여자들의 관계를 고찰한다. 차별화 된 QoS를 원하는 시간대에 사용하려는 사용자(고객)에게 더 높은 요금지불을 감내해야 한다는 것은 기본적인 경제관점이다 대역폭 리소스의 과다사용, 적절사용, 과소사용에 따른 차등화 된 요금을 적용하기 위해 실질적으로 사용자에 의해 소비된 리소스의 크기 v(t)를 기반으로 하는 누적요금계획(CPS) 기법을 제시한다. CPS는 미래에 상업적 네트워크의 중요한 관리기능을 결정한다. 이 논문에서는 EWM 기법을 적용하여, CPS를 이용하여 유연하면서도 합리적인 인터넷 요금구조, 시장관리기법, 투명성, 예측성, 단순성 등이 고려되는 인터넷 요금부과 시스템의 수정된 구현기법을 제시한다.

• 한국동물학회지
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• 제30권1호
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• pp.1-9
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• 1987

생쥐 난자-난구 복합체를 인공배양하면서 adenylate cyclase의 촉진제인 forskilin과 phosphodiesterase의 저해제인 3-isobutyl-1-methylxanthine(IBMX)을 배양액에 첨가하여 이들이 난구세포의 분산과 난자의 성숙(핵붕괴)에 미치는 효과를 관찰한 결과 다음과 같았다. 1. Forskilin은 0.001$\mu$M에서 부터 난구세포의 분산을 유도하기 시작하여 (36%) 0.1-10$\mu$M 구간에서 최대의 분산율을 나타내었고 (80-90%) 100$\mu$M에서는 그 효과가 줄어들었다(60%). 이때 난자의 핵 붕괴는 10$\mu$M까지 정상으로 일어나다 (75-80%) 100$\mu$M에서 부분적으로 억제되기 시작하였다(40%). 2. IMBX는 0.01$\mu$M에서 부터 난구세포의 분산을 유도하기 시작하여 (30%) 1-1,000$\mu$M의 전 구간에서 최대의 분산율(81-89%)을 나타내었다. 난자들은 10$\mu$M의 농도까지 정상적으로 핵 붕괴를 일으키었으나(90% 이상) 100$\mu$M 이상에서 급격히 억제되었다(14%). 3. 난구세포의 분산을 유도하는데 필요한 최소의 자극기간을 조사해 본 결과 HCG는 2분, FSH와 forskilin은 15-30분, IBMX는 2시간이었다. 위 결과로 부터 생쥐 난구세포에서 cAMP의 농도를 높이는데 adenylate cyclase 와 phosphodiesterase의 두 효소가 모두 중요한 기여를 하며 난구세포는 단 기간에 생긴 cAMP의 peak로서 분산이 유도될 수 있으나 난자의 성숙억제 과정에서는 지속적인 cAMP의 존재가 필요하다는 것을 알았다.

• 한국동물생명공학회지
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• 제35권4호
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• pp.357-365
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• 2020

The aim of present study was to investigate regulatory mechanism of alpha-linolenic acid (ALA) during in vitro maturation (IVM) on nuclear and cytoplasmic maturation of porcine oocytes. Basically, immature cumulus-oocyte complexes (COCs) were incubated for 22 h in IVM-I to which hormone was added, and then further incubated for 22 h in IVM-II without hormone. As a result, relative cumulus expansion was increased at 22 h after IVM and it was enhanced by treatment of ALA compared with control group (p < 0.05). During IVM process within 22 h, cAMP level in oocytes was decreased at 6 h (p < 0.05) and it was recovered at 12 h in ALA-treated group, while oocytes in control group recovered cAMP level at 22 h. In cumulus cells, it was reduced in all time point (p < 0.05) and ALA did not affect. Treatment of ALA enhanced metaphase-I (MI) and MII population of oocytes compared with oocytes in control group at 22 and 44 h, respectively (p < 0.05). Intracellular GSH levels in ALA group was increased at 22 and 44 h after IVM (p < 0.05), whereas it was increased in control group at 44 h after IVM (p < 0.05). In particular, the GSH in ALA-treated oocytes during 22 h of IVM was higher than control group at 22 h (p < 0.05). Lipid amount in oocytes from ALA group was higher than control group (p < 0.05). Treatment of ALA did not influence to absorption of glucose from medium. Cleavage and blastocyst formation of ALA-treated oocytes were enhanced compared with control group (p < 0.05). These findings suggest that supplementation of ALA could improve oocyte maturation and development competence through increasing GSH synthesis, lipid storage, and regulation of cAMP accumulation during early 22 h of IVM, and these might be mediated by cumulus expansion.

• 대기
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• 제21권4호
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• pp.391-404
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• 2011

This study investigates the impact of cumulus parameterization scheme (CPS) with different horizontal grid sizes on the simulation of the local heavy rainfall case over the Korean Peninsula. The Weather Research and Forecasting (WRF)-based real-time forecast system of the Joint Center for High-impact Weather and Climate Research (JHWC) is used. Three CPSs are used for sensitivity experiments: the BMJ (Betts-Miller-Janjic), GD (Grell-Devenyi ensemble), and KF (Kain-Fritsch) CPSs. The heavy rainfall case selected in this study is characterized by low-level jet and low-level transport of warm and moist air. In 27-km simulations (DM1), simulated precipitation is overestimated in the experiment with BMJ scheme, and it is underestimated with GD scheme. The experiment with KF scheme shows well-developed precipitation cells in the southern and the central region of the Korean Peninsula, which are similar to the observations. All schemes show wet bias and cold bias in the lower troposphere. The simulated rainfall in 27-km horizontal resolution has influence on rainfall forecast in 9-km horizontal resolution, so the statements on 27-km horizontal resolution can be applied to 9-km horizontal resolution. In the sensitivity experiments of CPS for DM3 (3-km resolution), the experiment with BMJ scheme shows better heavy rainfall forecast than the other experiments. The experiments with CPS in 3-km horizontal resolution improve rainfall forecasts compared to the experiments without CPS, especially in rainfall distribution. The experiments with CPS show lower LCL(Lifted Condensation Level) than those without CPS at the maximum rainfall point, and weaker vertical velocity is simulated in the experiments with CPS compared to the experiments without CPS. It means that CPS suppresses convective instability and influences mainly convective rainfall. Consequently, heavy rainfall simulation with BMJ CPS is better than the other CPSs, and even in 3-km horizontal resolution, CPS should be applied to control convective instability. This conclusion can be generalized by conducting more experiments for a variety of cases over the Korean Peninsula.

• 한국수정란이식학회지
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• 제12권1호
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• pp.111-116
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• 1997

The present study was carried out to produce in vitro fertilized embryos with immature follicular oocytes collected by transvaginal aspiration from Holstein cows. A simple aspiration apparatus consists of two stainless steel tubes, an inner tube (needle holder; 1.2cmdiameter, 55cm long) and an outer tube (1.5cm diameter, 4Scm long), and a hand-operated vacuum pump was used. Under epidural anesthesia, the needle guide was passed into the vagina of the cow to a point next to the cervix. An ovary was placed against the wall of the vagina over the end of the aspiration needle by rectal manipulation. As the needlepassed into the ovary, an assistant was asked to apply vacuum(l00mrnHg) and the ovary was manipulated back and forth in all directions over the needle. When all sites of the ovary was aspirated, the needle was withdrawn and the needle guide was moved to the other side of ovary and the procedure was repeated. When the oocyte aspiration procedure was finished, collected fluid was transported to laboratory. Oocytes surrounded with at least 1 layer of cumulus cells were matured, fertilized and cultured in vitro. The results were as follows; Ninety seven oocytes were collected by transvaginal aspiration from seventeen Holstein cows(5.7 /head). The number of oocytes surrounded with at least 1 layer of cumulus cells were 60(61.9%). Following in vitro maturation, fertilization and culture, the cleavage and development rate to morula+blastocyst were 83.3% and 30.0%, respectively. From this study, transferable in vitro fertilized embryos could be produced with imma- ture follicular oocytes collected by transvaginal aspiration from Holstein cows using a simple aspiration apparatus.

• 한국수정란이식학회지
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• 제26권4호
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• pp.251-256
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• 2011

Presently, the effect of 0.5 mM dibutyryl cAMP (dbcAMP)-supplemented maturation medium during different incubation time on meiotic arrest (germinal vesicle) and resumption (metaphase II) of porcine oocytes and embryonic development of porcine oocytes following in vitro fertilization (IVF) or parthenogenetic activation (PA) was determined. Porcine cumulus oocyte complexes (COCs) were cultured in 0.5 mM dbcAMP for 17, 22, 27, or 42 h, and an additional 22 h without 0.5 mM dbcAMP. The nuclear status was examined at each time point. Oocytes cultured from 39~49 h displayed more than 80% meiotic resumption. More than 85 % of meiotic arrest was presented at 17~22 h. Oocytes were cultured for 22 h with 0.5 mM dbcAMP and additional 22 h without dbcAMP to assess developmental potential following IVF or PA. There were no significant differences in blastocyst rates among the dbcAMPIVF, IVF, dbcAMP-PA, and PA groups, although cleavage rate of IVF group was significantly higher than those of dbcAMP-PA, and PA groups. In conclusion, 0.5 mM dbcAMP influenced meiotic maturation of porcine oocytes depending on incubation time of oocyte, although embryonic development was not improved in both IVF and PA.

• 한국수정란이식학회지
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• 제33권4호
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• pp.281-286
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• 2018

Zona pellucida (ZP), a primarily representative coat of mammalian egg and embryo, has an extremely heterogeneous morphology during different developmental stages. The objective of the present study was to compare the morphological changes of the ZP surface of immature, in vitro and in vivo matured canine oocytes by using scanning electron microscopy (SEM). Canine ovaries were collected from local veterinary hospitals to recover immature oocytes. The ovaries were sliced and the released cumulus oocyte complexes (COCs) were washed with TL-HEPES. The selected COCs were randomly divided into two groups, first group was processed immediately at immature state and the second group was processed 72 h after in vitro maturation, and compared with in vivo derived oocytes. Oocytes were fixed, critical point dried and examined under SEM. The diameters of oocyte and outer holes of the ZP were measured on a total of 249 oocytes; the results were analyzed using One-way ANOVA. Our results showed that, the diameter of immature oocytes significantly differed (p < 0.05) from that of in vivo matured oocytes ($79.60{\pm}0.77{\mu}m$ vs. $101.46{\pm}1.07{\mu}m$, respectively). Similarly, a significant difference (p < 0.05) in the diameters between those of in vitro and in vivo matured oocytes were found ($79.51{\pm}2.36{\mu}m$ vs. $101.46{\pm}1.07{\mu}m$, respectively). Moreover, the diameters of the outer holes of the ZP were significantly (p < 0.05) larger in in vivo matured ($1.48{\pm}0.42{\mu}m$) than in vitro matured for 72 and immature oocytes ($1.10{\pm}0.16$ and $0.43{\pm}0.12{\mu}m$, respectively). Taken together, these data indicates that the ZP surface is related to oocyte maturity in canine.