• The Journal of the Acoustical Society of Korea
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• v.30 no.1
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• pp.9-16
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• 2011

When a hydrofoil ship plies at high speed, there exist possibilities of collision with ocean mammals dwelling near the surface. An active sonar located within the immersed hydrofoil structure that provides the lift for the vessel, can be used for early warning of their presence. The proper functioning of the active sonar system depends on its ability to reject noise and pick up the target signal. In this article, we measured the noise on a hydrofoil of an operating ship with two flush-mounted hydrophones. The measurements were conducted for the purpose of (1) identifying the effect of operating state of machinery likes engine, cooler and generator (2) observing the change of noise depending on the measuring position (3) observing the change of noise with increasing ship speed. To verify our experiment, experiments were performed three times and the measured results are compared with other investigations and they show similarity to each other. The results are analyzed with frequency domain in order to apply to operating active sonar detecting system and focus on high frequency band within sonar's operating frequency region. Through these experiments and analysis, it is expected that we can identify the generated noise around hydrofoil where active sonar is installed and these results lead us to design active sonar that could distinguish target signal from noise more effectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.151-157
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• 2017

Recently, the retail industry has created efficient store operations, and has differentiated customer service through the future store. The intelligence of these stores is being applied by using technologies such as the Internet of Things (IoT), and the business process is being improved through this. The process also focuses on efficient store operations and service developments to provide customers with shopping convenience. The change in trends in the industry means that domestic distribution has already reached maturity. Even in countries where retail industries are mature, such as the U.S. and Europe, recent trends are moving toward maximizing operational efficiency and customer service. The reason is that many retailers have already reached saturation and survived the competition. This paper is a study of a drive-through service for automation and efficiency in receiving service after ordering by a customer of the distribution store. When ordering a product being purchased by a customer, the product picking process is done in a timely fashion through a picking scheduling agent. When the customer enters the store parking lot, a service supports the entry of information and finding a parking place so the customer can quickly pick up the goods. The proposed service can be applied to a retail store drive-through system, the distribution store's delivery system, the digital picking system, and indoor/outdoor large parking management systems, and it is possible to provide one-dimensional customer service through the application of IoT technology.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.3
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• pp.251-260
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• 1998

It is well known that the clinical test for responsibility of accurate fertilization capacity in male partners is very important to diagnose and treat the infertility. However, it has been reported that the traditional semen analysis cannot accurately predict fertilization and pregnancy potential. The present study was performed to evaluate the acrosomal reaction to ionophore challenge (ARIC) test as a prognostic indicator for fertilization of sperm and oocyte in an in vitro fertilization and embryo transfer (IVF-ET) program. From March 1996 to Februry 1997, 30 couples undergoing IVF program were allocated to this study group. All female partners in the study group were 35 years old or less and their serum level of basal follicle stimulating hormone (FSH) and estradiol $(E_2)$ were normal. All the male partners have normal parameters of semen analysis. The ARIC tests were performed on the day of ovum pick up and in vitro insemination in all the male partners. The controlled ovarian hyperstimulation (COH) using luteal long protocol of gonadotropin releasing hormone (GnRH) agonist was used in all couples for IVF-ET. The acrosomal reaction with $10{\mu}l$ of 10% DMSO was induced spontaneously in $10.1{\pm}9.8%$, and acrosomal reaction with calcium ionophore A 23187 was induced in $27.4{\pm}18.1%$, and the ARIC value was $17.4{\pm}16.2%$. There were no significant correlation between the ARIC value and the fertilization rate ($r^2$=0.044, p=0.268). There were also no significant correlation between the ARIC value and the percentage of the grade I, II embryos ($r^2$=0.046, p=0.261). On the basis of above results, it was suggested that ARIC test might not be a useful prognostic indicator for fertilization in IVF-ET in male partners with normal parameters of conventional semen analysis. We guessed that IVF-ET could be performed to the patients primarily without universal appilcation of ARIC test to all male partenrs, and if fertilization failure occurs, the micro assisted fertilization (MAF) such as intracytoplsmic sperm injection (ICSI) might be used as an alternative mode of treatment with acceptable success rate.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.107-110
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• 2001

제철소에서 매년 대량 발생되어 주로 매립처분되고 있는 제강분진의 재활용 방안으로서, 폐수처리분야에 널리 사용되고 있는 펜톤산화공정의 반응촉매원인 Fe 공급원으로서 제강분 진의 활용 가능성에 대한 연구를 수행하였다. 본 연구에서는 포항제철소에서 제철부산물로 발생되는 제강분진을 전처리 없이 산화촉매로 사용하여 김포 수도권 매립지의 침출수 처리 공정에서 펜톤산화조에 유입되는 원수를 대상으로 과산화수소에 의한 산화처리 실험을 수행하였다. 반응은 회분식으로 수행하였으며, 일반적으로 알려진 펜톤산화반응의 주요 반응조 건인 운전 pH, 과산화수소 주입량 및 분할주입, 제강분진의 주입량 등의 변화에 따른 각 조 건별 시간에 따른 반응결과를 알아보았다. 또한 기존의 Fe 공급원으로 사용되고 있는 FeSO$_4$와 처리성능 및 적용조건에 대한 비교 실험도 수행하였다. 침출수 수질변화는 TOC (Total Organic Carbon) analyzer를 사용하여 측정한 TOC값으로 나타냈으며, pH controller 와 정량펌프를 사용하여 HCl과 NaOH주입을 통해 반응기간동안 일정 pH를 유지하였다. 본 연구결과, 최적 pH 조건인 4에서 최대 75% TOC 제거율을 나타내었으며, 대부분의 반응은 30분 이내에 이루어졌다. 주어진 실험조건에서 FeSO$_4$와 비교하여 반응속도와 처리효율에서 향상된 결과를 나타내었으며 반응 후 응집침전실험에서도 보다 높은 처리효과를 얻을 수 있었다. 결론적으로, 과산화수소/제강분진 시스템을 이용한 화학적 산화처리방법은 경제성과 처리성능에서 기존의 펜톤산화공정의 대체방안으로서 향 후 적용가능성이 높을 것으로 기대된다.g, 200 mg/kg, 300 mg/kg의 순서로 함량이 점차 감소하는 결과를 얻을 수 있었다. 이상의 결과를 종합하여 볼 때 가자 메탄올추출물은 PQ 유도독성을 신장 및 폐조직에서 효과적으로 경감시키는 것으로 나타났다.ted retailers ("sellers") must accept end-of-life items returned to them by the consumers. At the local level, Taipei City implements a pay-as-you-throw program, whereby citizens pay waste collection and treatment fees through the purchase of special trash bags approved by the Taipei City Government. However. recyclables that are separated by citizens are collected free-of-charge by the City. Taichung City and Kaohsiung City, on the other hand, enforce mandatory sorting schemes, whereby citizens face penalties if they don't separate recyclables from the trash before pick-up. These programs have resulted in a significant reduction in municipal waste. Per capita waste collected per day has dropped from 1.143

• Clinical and Experimental Reproductive Medicine
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• v.44 no.1
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• pp.33-39
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• 2017

Objective: The aim of this study was to assess the changes of follicular fluid (FF) and serum levels of cerebellin precursor protein 1 (cbln1) and betatrophin in patients with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) with a gonadotropin-releasing hormone (GnRH) antagonist protocol. Methods: Twenty infertile women with PCOS and 20 control women diagnosed as poor responders undergoing ovarian stimulation with a GnRH antagonist were included. Blood samples were obtained during ovum pick-up. Follicular fluid from a dominant follicle was collected from the subjects. Using enzyme-linked immunosorbent assays, FF and serum levels of cbln1 and betatrophin were measured in both groups of participants. Metabolic and hormonal parameters were also determined and correlated with each other. Results: Both groups of women had similar serum and FF betatrophin levels ($55.0{\pm}8.9ng/mL$ vs. $53.1{\pm}10.3ng/mL$, p=0.11). The serum and FF betatrophin levels of poor responders were found to be similar ($49.9{\pm}5.9ng/mL$ vs. $48.9{\pm}10.7ng/mL$, p=0.22). Conversely, the FF cbln1 levels of PCOS women were found to be significantly higher than the serum cbln1 levels ($589.1{\pm}147.6ng/L$ vs. $531.7{\pm}74.3ng/L$, p<0.02). The FF cbln1 levels of control participants without PCOS were significantly higher than their serum cbln1 levels ($599.3{\pm}211.5ng/L$ vs. $525.3{\pm}87.0ng/L$, p=0.01). Positive correlations were detected among body mass index, insulin resistance, serum insulin, total testosterone, and betatrophin levels in the PCOS group. Conclusion: Follicular fluid betatrophin and cbln1 concentrations may play a pivotal role on follicular growth in PCOS subjects undergoing IVF/ICSI with an antagonist protocol.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.258-263
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• 1995

미래 정보와 시대에서 중추적인 역할을 할 광관련 멀티미디어 장비들은 최근 관련 산업계에서 주목을 받기 시작하고 있고 특히 기존 VTR(Video Tape Recorder) 시장을 대체할 차세대 DVDR(Digital Video Disk Recorder)는 기술전쟁이라고 할 정도로 선진 기업의 연구가 치열해지고 있다. DVDR 시스템에서는 필요한 정보들을 레이저빔을 이용한 광학신호로 바꾸어 광디스크에 기록, 재생하는 광픽업이 절대적으로 필요하게 된다. 그런데 광픽업의 위치추종기구인 Actuator는 정확한 위치추종(.+-.1.$\mu$m 오차이내)을 할 수 있는 성능이 요구되며 서보의 특성상 20KHz 이하에서 불필요한 모우드가 가진되지 않는 정밀부품이어야 하므로 Actuator 각 부품의 동적인 특성을 명확히 규명할 필요가 있다. 따라서 본 연구에서는 우선 Actuator 각 부품과 가동부 전체의 중량 및 진동해석을 통해 동특성을 조사하였다. 그리고 Actuator의 중요한 기본성능중 하나인 구동감도 확보여부를 검토할 필요가 있기 때문에 유한요소법 프로그램인 ANSYS를 이용하여 자기회로 부분에 대한 해석을 구하였다. 또한 가동부와 자기회로 등 하위부품을 조립하는 과정에서 발생하는 조립오차로 인해 불필요한 공진과 회전형상이 야기될 수 있으므로 동특성 및 문제점 파악을 위한 민감도 분석이 필요하다. 따라서 본 연구에서는 가동부의 관성 모멘트 값과 강체에 대한 일반식을 이용한 자체 프로그램을 작성하여 조립공차를 구하였다. 이와같은 과정을 통해 구해진 설계값을 바탕으로 실제 제작된 Actuator에 대해서는 비접촉식 측정방법을 통해 동특성값을 측정하였고 이를 해석값과 상호 비교하였다.동강성행렬법(dynamic stiffness matrix method)을 이용하여 해석하고자 한다. 수준임이 입증되었다. 본 연구의 결과를 토대로우리나라 젊고 건강한 남성에게 적합한 무게상수는 작업자군에 대하여 25.05kg, 학생군에 대하여 20.24kg 으로 나타나 이는 미국 NIOSH 안전기준과 대체로 일치함을 발견하였다.ive structures utilized in Client/server architecture for distribution and cooperative processing of application between server and client this study presents two different data management methods under the Client/server environment; one is "Remote Data Management Method" which uses file server or database server and. the other is "Distributed Data Management Method" using distributed database management system. The result of this study leads to the conclusion that in the client/server environment although distributed application is assumed, the data could become centralized (in the case of file server or database server) or decentralized (in the case of distributed

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.293-307
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• 2020

Every year, the floating macroalgae, green and golden tide, are massively detected at the Yellow Sea and East China Sea. After influx of them to the aquaculture facility or beach, it occurs enormous economic losses to remove them. Currently, remote sensing is used effectively to detect the floating macroalgae flowed into the coast. But it has difficulties to detect the floating macroalgae exactly because of the wavelength overlapped with other targets in the ocean. Also, it is difficult to distinguish between green and golden tide because they have similar spectral characteristics. Therefore, we tried to distinguish between green and golden tide applying the Deep learning method to the satellite images. To determine the network, the optimal training conditions were searched to train the AlexNet. Also, Gaofen-1 WFV images were used as a dataset to train and validate the network. Under these conditions, the network was determined after training, and used to confirm the test data. As a result, the accuracy of test data is 88.89%, and it can be possible to distinguish between green and golden tide with precision of 66.67% and 100%, respectively. It is interpreted that the AlexNet can be pick up on the subtle differences between green and golden tide. Through this study, it is expected that the green and golden tide can be effectively classified from various objects in the ocean and distinguished each other.

• Korean Journal of Materials Research
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• v.8 no.3
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• pp.268-273
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• 1998

Standard Zircaloy-4 sheets, charged with 230-250ppm hydrogen by the gas-charging method and homogenized at $400^{\circ}C$ for 72hrs in a vacuum, were corroded in pure water and aqueous LiOH solutions using static autoclaves at $350^{\circ}C$. Their corrosion behaviors were characterized by measuring their weight gains with the corrosion time and observing their microstructures using an optical microscope and a scanning electron microscope. The elemental depth profiles for hydrogen and lithium were measured using a secondary ion mass spectrometry(S1MS) to confirm their distributions at the oxidelmetal interface. The normal Zircaloy-4 specimens corroded abruptly and heavily at the concentration of Li ions more than 30ppm in the aqueous solution. This is due to accelerations by the rapid oxidation of many Zr- hydrides formed by the large amount of absorbed hydrogen, resulting from the increased substitution of $Li^{+}$ ions with $Zr^{4+}$-sites in the oxide as the Li ion concentration increased. The specimens that had been charged with amounts of hydrogen greater than its solubility corroded early with a more rapid acceleration than normal specimens, regardless of the corrosion solutions. At longer corrosion times. however, normal specimens showed a rather accelerated corrosion rate compared to the hydrogen-charged specimens. These slower corrosion rates of the hydrogen-charged specimens at the longer corrosion times would be due to the pre-existent Zr-hydride in the matrix, which causes the hydrogen pick- up into the specimen to be depressed, when the oxide with an appropriate thickness formed.

• Korean Journal of Animal Reproduction
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• v.24 no.1
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• pp.83-88
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• 2000

This study was conducted to determine the effect of repeated ultrasound-guided transvaginal retrieval of oocytes recovery, estrous cycle and ovarian adhesion in Korean native, Hanwoo heifers. Heifers were at unknown stages of the estrous cycle at the start of experiments in which all follicles $\geq$6mm in diameter were ablated. The results obtained in this study were as follows; Follicle developing number and oocytes collected number were no effected to repeated OPU to nine session, 4 e.a range oocytes collected to repeated OPU session. Oocytes were observated follicles were 8.7$\pm$4.2 e.a, collected oocytes were 4.1$\pm$3.4 e.a to two times collected per week and observated follicles was 10.2$\pm$6.1 e.a, collected oocytes were 4.3$\pm$2.9 e.a to one times collected per week, but no difference significantly(P＜0.05). Ovaries adhesive percentage to repeated OPU was eight ovaries adhisived(20%) of forty ovaries, three ovaries(7.5%) to 1~3 times oocytes collected, four ovaries(l0%) to 4~6 times, one ovaries(2.5%) to 7~9 times oocytes collected session. To repeated OPU effection, ovaries adhisive heifers were long estrous cycle(＞25 day) to 7 heads(87.5%) of 8 head, non-adhesive ovaries heifers were 5 heads(41.7%) were long estrous cycle to repeated OPU 12 heads. Although, now unknown about the dynamics of follicles wave and about functional changes to repeated OPU ovaries, more question about ovaries adhesive cause remain.

• Journal of Korean Public Health Nursing
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• v.16 no.1
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• pp.45-63
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• 2002

The purpose of this study is to understand the current status of high school students' exposure to pornographic materials as well as to provide basic data to develop sex education programs. This study was conducted through a self-administered questionnaire survey of 774 students of six high schools in Seoul, three boys' and three girls' respectively, from August 22 to August 25, 2000. This study shows that high school students' exposure to pornographic materials such as CD-ROMs, internet, video tapes and adult movies has become very serious. The results of this study are as follows. 1. Among the students surveyed, $23.5\%$ of them currently has opposite-sex friends, while $42.2\%$ used to have and $34.2\%$ has never had opposite-sex friends. 2. $55.3\%$ of the students pick up their sexual knowledge from their friends, followed by mass media $(47.5\%),\;school (21.1\%),\;adult\; magazines (17.1\%)\;, internet (14.1\%)$, pornography visual $materials (11.5\%),\; sexual\; books (3.6\%)$ and pornography printed $materials (2.4\%).$ 3. Regarding the frequency of sexual education taken in school, $54.2\%$ of the students answered 'often', while $37.6\%$ answered 'almost none', 'several times' $(4.4\%)$, 'never' $(2.9\%)$ and 'frequently' $(0.9\%)$, respectively. Regarding sexual education at home, $42.2\%$ answered 'almost none', followed by 'never' $(36.3\%)$, 'often' $(16.3\%)$, 'several times' $(3.3\%)$ and 'frequently' $(1.8\%)$, respectively. 4. $68.2\%$ of the students have been exposed to adult movies, followed by pornography videos $(60.1\%)$, internet chatting $(50.2\%)$ and pornography computer diskettes $(38.0\%)$. 5. The degree of exposure to pornographic materials of boy students is much higher than that of girl students. 6. It appears that there is an interrelation between the kind of schools and the degree of the students' exposure to pornographic materials. 7. The higher the students' grade is. the more they have been exposed to pornographic materials. 8. It shows that there is an interrelation between the students' academic performance and the degree of their exposure to pornographic materials. 9. There is also an interrelation between the amount of students' pocket money and the degree of their exposure to pornographic materials. 10. There is an interrelation between the degree of their adaptation to school life and the degree of their exposure to pornographic materials. 11. It appears that there is an interrelation between their parents' relations with them and the degree of the students' exposure to pornographic materials. 12. There is a significant difference in the degree of their exposure to pornographic materials in accordance with their residential area. 13. There is also a significant difference in the degree of their exposure to pornographic materials in accordance with the average income of their families. 14. There is also a significant difference in the degree of their exposure to pornographic materials in accordance with the mean sexual education at home.