• Proceedings of the Korea Contents Association Conference
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• 2012.05a
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• pp.249-250
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• 2012

현재 도서관 통합관리시스템의 소프트웨어 사용 방식은 클라이언트/서버 및 ASP 방식으로 서비스를 제공함으로써 하드웨어 및 소프트웨어 구매비, 설치 및 배포, Customization, Upgrade, 문제점 관리, 라이센스의 고비용 등 소프트웨어 전반에 걸쳐 관리가 힘들고 고비용의 문제점이 있다. 이러한 문제점을 해결하기 위해 모바일 클라우드 기반의 스마트도서관 정보서비스시스템에서는 멀티테넌트 환경에서 구현이 가능한 핵심요소들을 개발하였다. 그러므로 초기 투자비용이 거의 없고, 쉽고, 간편하며, 저비용 IT 서비스가 가능한 SaaS 기반의 소프트 웨어 온-디멘드 방식의 서비스 모델로 시스템을 구현하였다. 제안 시스템은 연결방식으로는 N고객:1인스턴스, 제공 프로그램은 동일한 코드 사용, 커스터마이징은 고객이 테넌트별 환경 설정을 통해서 직접 수정가능, 데이터는 테넌트별 자료를 공유해서 사용할 수 있으며 기존의 ASP 서비스의 단점을 해결할 수 있도록 성능을 개선하였다.

• Proceedings of the Korea Contents Association Conference
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• 2013.05a
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• pp.263-264
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• 2013

기존의 도서관 정보서비스는 도서관 업무담당자에 의한 1:n 방식의 온라인 지식서비스만을 강조하였다면 스마트 도서관시스템에서는 빅데이터를 통해 지식을 생성, 검증, 분류하여 지능형지식, 실감형지식, 맞춤형지식, 체험형지식 등을 제공할 수 있다. 또한 빅데이터를 활용한 다자간 콘텐츠 공유, 상호 의견 교환이 가능하며, 집단지성에 의해 구축되는 학습 콘텐츠 및 지식 베이스는 국가의 지식자원 경쟁력을 향상시킬 수 있으며, 차세대 이러닝 환경에서의 지능형 튜터링을 통해 창의적 인재육성, 공교육의 질적 향상, 사교육비 절감, 교육 기회 균등 배분, 지역 및 계층 간 위화감 해소 등 국가정책 목표 실현할 수 있다. 제안된 빅데이터 기반의 스마트도서관 정보서비스시스템에서는 멀티테넌트 환경에서 구현이 가능한 핵심요소들을 개발하였다. 그러므로 초기 투자비용이 거의 없고, 쉽고, 간편하며, 저비용 IT 서비스가 가능한 SaaS 기반의 소프트웨어 온-디멘드 방식의 서비스 모델로 시스템을 구현하였다. 또한 연결방식으로는 N고객:1인스턴스, 제공 프로그램은 동일한 코드 사용, 커스터마이징은 고객이 테넌트별 환경 설정을 통해서 직접 수정가능, 데이터는 테넌트별 자료를 공유해서 사용할 수 있으며 기존의 디지털도서관 시스템 서비스의 단점을 해결할 수 있도록 성능을 개선하였다.

• Electronics and Telecommunications Trends
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• v.19 no.5 s.89
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• pp.114-124
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• 2004

유선 네트워크, 무선 이동통신 네트워크, 인터넷 등을 통합하는 유무선 통합 네트워크(BcN)에서는 VoIP기술을 사용하게 될 것이다. TTA 표준으로 2004년 7월에 제정된 VoIP 계층형 광대역 고품질 음성 코덱은 핵심계층에 G.711, G.723.1, G.729를 사용하므로 10종의 PT 를 설정하여 코덱을 협상한다. 이로 인하여 자기자신의 코덱 이외에도 G.711, G.723.1, G.729 등과 상호 호환이 되는 장점을 갖는다. 본 고는신규로 제정된 VoIP 계층형 광대역 고품질 음성 코덱을 네트워크에서 사용할 수 있도록 호 처리에 대한표준화를 추진하여야 하는데 이를 위한 표준 기술을 설명하고, 코덱과 호처리 관계 및 표준화 기술을 근거로 한 코덱 협상 처리 기술을 설명한다. 코덱 협상 처리 기술로서 PSTN/MSC 연동 코덱 협상 방안과All IP 코덱 협상 방안으로 구분하였다. All IP 코덱 협상 방안에서는 발신, 착신, MGC, 착신서버에서 호환성을 위한 호 처리 기능을 제공한다. 본 고의 호 처리 기술을 적용하면, VoIP 계층형 광대역 고품질 음성코덱은 기존 네트워크 장치 기능을 수정하지 않고 사용할 수 있다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.177-183
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• 1999

In this paper, we analyze transmission characteristics of ultrashort laser pulses using the property of Raised-cosine pulse which are systematically obtained following Class-2 PRS model. The high-order pulses are easily derived front a modified PRS system model as Class-1 PRS model. This may be based on the fact that the spectra and bandwidths of the high-order pulses are beautifully related to their orders. And we make clear they are very useful to cover wider area and more accurate transmission characteristics of ultrashort pulses than Gaussian or Sech pulse approximations used conventionally. First modifying the generalized PRS system model, we propose a new model for deriving any type of high-order pulse. And we offer a novel analysis method of ultrashort pulse transmission which has any shape and FWHM, using the proposed model. In addition, by fixing the pulse range $\tau$=1(ps) and varying the order of the pulse from n=1 to n=100, we obtain spectra of ultrashort pulses with 1(ps)-100(fs) FWHM's, and width of FWHM in the Class-2 PRS model 50~100(fs) smaller than Class-1 PRS model. As a one-step further, we derive PSD's of their pulse trains when they are applied to Unipolar signaling scheme. These PSD's are derided in the range of possible pulse intervals. All of these results are not only coincided with some conventional experimental works but also will to applied to any pioneering ultrashort pulse in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.237-242
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• 1999

In this paper, we analyze transmission characteristics of ultrashort laser pulses using the property of high-order pulses which are systematically obtained following their orders. The high-order pulses are easily derived from a modified PRS system model. But we make clear they are very useful to cover wider area and more accurate transmission characteristics of ultrashort pulses than Gaussian or Sech pulse approximations used conventionally. This may be based on the fact that the spectra and bandwidths of the high-order pulses are beautifully related to their orders. first modifying the generalized PRS system model, we propose a new model for deriving any type of high-order pulse. And we offer a novel analysis method of ultrashort pulse transmission which has any shape and FWHM, using the proposed model. In addition, by fixing the pulse range $\tau$=1(ps) and varying the order of the pulse from n:1 to n=100, we obtain spectra of ultrashort pulses with 1(ps)-150(fs) FWHM's, which are widely used in fiber communications. As a one-step further, we derive PSD's of their pulse trains when they are applied to Unipolar signaling scheme. These PSD's are decided in the range of possible pulse intervals. All of these results are not only coincided with some conventional experimental works but also will be applied to any pioneering ultrashort pulse in the future.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.2
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• pp.135-142
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• 2010

Objective: To evaluate the effectiveness of soft stimulation protocol using GnRH antagonist/clomiphene citrate (CC)/recombinant FSH (rFSH) in patients undergoing controlled ovarian stimulation (COS) with intrauterine insemination (IUI), compared with GnRH antagonist multiple dose protocol (MDP) using GnRH antagonist/rFSH. Methods: Eighty infertile women were randomized to soft stimulation protocol group (n=40) or GnRH antagonist MDP group (n=40). In both groups, IUI was performed 36~40 hours after hCG injection. Statistical analysis was performed using Student's t-test, $\chi^2$ test or Fisher's exact test as appropriate. Results: Total dose and days of rFSH required for COS were significantly fewer in soft stimulation protocol group (p<0.001, p<0.001). A premature LH surge did not occur in any patients of both groups. Clinical pregnancy rate per cycle was similar between the two groups. Conclusion: Soft stimulation protocol provides comparable pregnancy rates to GnRH antagonist MDP despite fewer total dose and days of rFSH, and so can become one of the patient-friendly, cost-effective alternatives for infertile patients undergoing COS with IUI.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.4
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• pp.1-6
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• 1992

The finite difference simulation method for ship waves is introduced for hull form improvement. Numerical simulations were performed for a series of modified hull forms and the simulated results were used for the determination of the better hull forms. A 4,400 TEU container carrier which was designed and experimented in towing tank was chosen for the purpose. The calculation results are compared with those of model test, of simplified Neumann-kelvin problems and of Rankine source method. In this study, it is shown that the combination of the computer simulation by our method with the experiment provides one of the most economical and reliable procedures of hull form improvement and that the degree of accuracy of this method is so high that it can cope with very practical design purposes.

• Composites Research
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• v.19 no.4
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• pp.1-6
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• 2006

The effects of aging on fatigue of PSF/AS4 laminates tvas studied using the new energy release rate analysis. The analysis by the variational mechanics has been useful in providing fracture mechanics interpretation of matrix microcracking in cross-ply laminates. This paper describes the changes of the critical energy release rate ${\Delta}Gmc$(microcracking toughness) about the variation of the aging period during fatigue loading. The master plot by modified Pans-law gives a characterization of a material system's resistance to microcrack formation. PSF/AS4 $[0/902]_s$ laminates were aged at four different temperatures based on the glass transition temperature for 60 days. At all temperatures, the toughness decreased with aging time. The decrease of the toughness at higher temperature was faster than at lower temperature. To assess the effects of aging on fatigue, the unaged laminates were compared with the laminates which were aged for 60 days at $170^{\circ}C$ near $180^{\circ}C\;T_g$. The slope of dD/dN versus A 6u, of the aged laminates was lower than that of the unaged laminates. There was a significant shift of the aged data to formation of microcracks at the lower values of ${\Delta}G_m$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.214-222
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• 2008

The equivalent circuit for the RLH-TL is proposed considering radiation effects due to the inclusion of a series capacitor and shunt inductor in a unit cell for the right/left-handed transmission line(RLH-TL). The design equations to realize a specific phase shift at a given frequency is also provided. The S-parameters for unit cells with N=1, 3, 5, and 10 are analyzed in various aspects based on the EM and circuit simulations especially for the purpose of controlling radiation along RLH-TL's. A modification formula for the radiation rate per unit cell is also proposed for good agreement between the EM and circuit simulation results.

• Clinical and Experimental Reproductive Medicine
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• v.36 no.2
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• pp.111-119
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• 2009

Objective: The aim of this study was to compare the clinical efficacy of clomiphene citrate (CC) and letrozole combined with gonadotropins for controlled ovarian stimulation (COS) in patients with CC-induced thin endometrium Methods: Fifty-one intrauterine insemination cycles performed in patients who previously had a thin endometrium (<8 mm) to ovulation induction using CC were included in this study. A CC 100 mg/day (CC+gonadotropin group, n=26) or letrozole 2.5 or 5 mg/day (letrozole+gonadotropin group, n=25) was administered on day 3~7 of the menstrual cycle, combined with gonadotropins at dose 75~150 IU every other day starting on day 5~7. We compared total dose of gonadotropin used, endometrial thickness, endometrial pattern, number of follicles ${\geq}14\;mm$ on hCG day, pregnancy rate and multiple pregnancy rate between the two groups, which were statistically analyzed using Mann-Whitney U test or Fisher's exact test, where appropriate. Results: There were no significant differences in clinical characteristics such as age, duration of infertility, number of previous IUI cycles, basal serum hormone levels and cause of infertility between the two groups. In both groups, the endometrium was significantly thicker than that of previous ovulation induction cycles using CC. No significant differences were found in the total dose of gonadotropin used, day of hCG administration, the rate of triple endometrium and pregnancy rate. The number of follicles ${\geq}14\;mm$ was significantly lower ($3.7{\pm}1.7$ vs. $2.8{\pm}1.7$, p=0.03) and the endometrium on hCG day was significantly thicker ($7.7{\pm}1.5$ vs. $9.1{\pm}1.7$, p=0.001) in letrozole+gonadotropin group compared to CC+gonadotropin group. Conclusion: The clomiphene citrate and letrozole combined with gonadotropins appear to avoid the undesirable effects on the endometrium frequently seen with CC for ovulation induction. However, in terms of adequate endometrial development or optimal follicular growth, letrozole may be more beneficial than CC for gonadotropin-combined COS in patients with CC-induced thin endometrium. Further prospective randomized controlled studies in a larger scale will be necessary to confirm our findings.