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

• Journal of the Korean Society for Library and Information Science
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• v.35 no.2
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• pp.151-170
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• 2001

Pricing for e-journals has become more complex than before-certainly much more complex than print pricing has ever been. E-journals charge either a fiat fee based on print, user, library size, usage, and combination. A survey of publisher's pricing structure found that print based model is popular followed by user based model. The current pricing situation is far from equitable and can be improved if publishers can be coerced to change their pricing practices. This study focus on a number of possible pricing models that may supplement and/or possibly replace the current print based model. With the possibility that its pricing will eventually be based strictly according to usage, may lead to the most equitable pricing model as well as the most efficient use of society's resources. Libraries can alleviate the pricing problem by encouraging library organizations and university consortia to exploit their potential monopoly power into a bilateral monopoly situation.

• Journal of Embryo Transfer
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• v.18 no.1
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• pp.61-68
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• 2003

Considerable attention has been focused on the cryopreservation of semen and estrus induction in dog, as consequence of poor productivity caused by long anestrus period, in order to enhance the productivity of youngs and to preserve the breeds. The objectives of this study were to improve reproductive efficiency of artificial insemination with fresh- and frozen-semen following estrus induction in dog. Fifty infertilie dogs (age 2~3 years) were selected fur the study and divided into three different estrus induction treatment groups. Group 1 : dogs (n=15) were given clomifene (0.1 mg/kg) orally f3r five days at 12 hr intervals. Croup 2: dogs (n=15) were given bromocriptine (50 $\mu$g/kg) orally for five days at 12 hr intervals, followed by single injection intravenously of 500 IU GnRH (Croup 3, n=20) when pro-estrus occurred. After being treated, the dogs were evaluated fur the rates of estrus induction and time interval lapses from treatment to beginning of the pro-estrus. The rates of pregnancy in estrus inducted dogs mated naturally compared to those inseminated artificially with ejaculated fresh semen and frozen-thawed semen. Estrus detection was performed using the method of vaginal smear and confirmed by the plasma progesterone assay. Pregnancy was confirmed by ultrasonograpy on day 25, 35 and 55 post insemination. The ejaculated semen was exposed to a mixture of Tris extender with cryoprotectant (Trisma, 81 mM; TES, 209 mM; citric acid, 6 mM; glucose, 5 mM; glycerol, 8%) and cryopreserved gradually by slow-cooling at 17 co above the surface of liquid nitrogen (L$N_2$) for 23 min. The use of fresh semen, the pregnancy rates were observed 66.6, 66.6, 75.0 and 83.3% in natural estrus, clomifene induced, bromocriptine induced and a combination of GnRH and bromocriptine, respectively. The use of frozen-thawed semen, the pregnancy rates were observed 66.6, 33.3, 50.0 and 60.0% in natural estrus, clomifene induced, bromocriptine induced and a combination of GnRH and bromocriptine, respectively. No difference was observed in the number of offspring produced among natural estrus and treated groups inseminated with fresh or frozen-thawed semen. In conclusion, there was no significant differences in the pregnancy rate of dogs between group treated with a combination of GnRH and bromocriptine and group treated clomifene or bromocriptine only. However, frozen-thawed semen can be used successfully fur artificial insemination in dog.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.43-43
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• 2004

국제적인 시각비교를 위해 GPS를 이용하고 있으나, GPS 신호에는 위성까지의 거리정보뿐 아니라 위성시계, 대류층, 이온층, 다중경로 오차 등이 포함되어 있다. 그 중 이온층 지연시간을 측정하기 위해서는 Ll과 L2 반송파 신호로부터 얻어지는 P코드와 위상정보를 이용할 수 있다. 반송파 위상 정보는 P코드보다 해상도가 좋기 때문에 위상정보를 이용하게 되면 고정밀도의 이온층 지연시간을 얻게 된다. 이온층 지연시간을 통해 총전자수를 나타내는 TEC 값을 얻을 수 있는데, 관측지점으로부터 시간에 따라 가장 높은 고도의 위성을 선택하여 P코드와 반송파 위상 정보를 통한 이온층 총전자수를 파악하고 정밀도를 비교분석 하였다. (중략)

• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.231-244
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• 1990

As the complexity of society increases, the demand for the forest-based recreational site is also increased. This, in turn. makes congestion an ubiquitous type of externality in forest-based recreational site. Efficient resource allocation requires this congestion effect to be accounted and considered in the decision making process. In this content, this study was conducted to suggest a process which can be used to measure the congestion and determine the optimal number of users. Willigness to pay(WTP) function obtained from Book Han San National Park users suggested that every 20.000 users increased decrease the satisfaction of users obtained from the site visit be 27.3%. For the purpose of demonstration this WTP function is applied tit determine the optimal number of users which is estimated as about 73,000 persons per day.

• Journal of the Korean Society for Library and Information Science
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• v.54 no.2
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• pp.105-125
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• 2020

This study attempts to identify the influence factors on the numbers of visitors and reference room users of public libraries through log-log multiple regression models, using the Korean National Libraries Statistical Data 2018. The fact found is summarized as follows; Even though books collection and seating capacities might be the most important factors in attraction of visitors and reference room users to public libraries in the past when the storage and propagation of knowledge and information was the top function of public libraries, very various and compound factors such as cultural or lifetime education programs, library operation, and user activities have an effect on inducing people to visit and use public libraries at present. This means that these days, public libraries are being transformed into some kinds of comprehensive cultural center where software elements such as cultural programs, user education, events, budget, membership, opening days, building style and age, and group activities rather than hardware elements such as books, literature material, and facilities constitute their essential parts in connection with visitor and user induction.

• Bulletin of the Korean Space Science Society
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• 1994.04a
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• pp.9-9
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• 1994

• Korean journal of applied entomology
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• v.43 no.3 s.136
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• pp.211-215
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• 2004

Temperature-fecundity of the melon aphid, Aphis gossypii Glover, was studied at constant temperatures ranging from 15 to $32.5^{\circ}C$ under $60-70\%$ RH and a photoperiod of 16 : 8 (L : D) A life table parameters were constructed using the results. The longevity of A. gossypii gradually increased with decreasing temperature below $27.5^{\circ}C$. Also fecundity increased with decreasing temperature and the highest fecundity was 61.8 nymphs per female at $17.5^{\circ}C$. However. daily fecundity increased with increasing temperatures up to $22.5^{\circ}C$ showing 5.9 nymphs per day and thereafter decreased. Longevity and fecundity of the adult in the greenhouse with an average temperature of $21^{\circ}C$ and $65.6\%$ RH, were 20.0 days and 59.6, respectively, which were longer and higher than those in the growth chamber with similar conditions. net reproductive rate (Ro) was 54.9 at $17.5^{\circ}C$ while intrinsic rate of increase ($r_m$) and finite rate of increase ($\lambda$) were the highest 0.5 and 1.6 at $30^{\circ}C$, respectively. doubling time (DT) and mean generation time (T) were the shortest 1.4 and 6.8 at $30^{\circ}C$ indicating that optimal temperature for the development is $30^{\circ}C$.

• Journal of Astronomy and Space Sciences
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• v.16 no.2
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• pp.285-292
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• 1999

To determine a geographical position by GPS signal, the effect of the ionosphere must be considered to improve accuracy. This has led us to continuously try to find the TEC of the ionosphere by using the GPS signal. So far the way to find TEC has been developed and the information obtained from this can be used not only to increase the accuracy of determining the position, but also to study the ionosphere. In this research, the TEC MAP over Korea was obtained by using the data collected from eight GPS stations around the Far East Asia, which is the common way to represent TEC over some regional or global region.

• 정보화사회
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• s.148
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• pp.57-65
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• 2001

한국인터넷정보보호센터는 전문조사기관인 인터넷 메트릭스 사에 의뢰해 지난해 11월20일부터 12월 23일까지 전국 3,452가구 1만 186명을 대상으로 ‘인터넷 이용자 실태조사’를 실시했다. 인터넷을 얼마나 많은 사람들이 이용하는자, 또 어떻게 이용되는지 살펴보기로 한다.