• 한국도서관정보학회지
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• 제21권
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• pp.253-289
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• 1994

The purpose of this study is about the search pattern of LINNET (Library Information Network System) OPAC users by transaction log, maintained by POSTECH(Pohang University of Science and Technology) Central Library, to provide feedback information of OPAC system design. The results of this study are as follows. First, for the period of this analysis, there were totally 11, 218 log-ins, 40, 627 transaction logs and 3.62 retrievals per a log-in. Title keyword was the most frequently used, but accession number, bibliographic control number or call number was very infrequently used. Second, 47.02% of OPAC, searches resulted in zero retrievals. Bibliographic control number was the least successful search. User displayed 2.01% full information and 64.27% local information per full information. Third, special or advanced retrieval features are very infrequently used. Only 22.67% of the searches used right truncation and 0.71% used the qualifier. Only 1 boolean operator was used in every 22 retrievals. The most frequently used operator is 'and (&)' with title keywords. But 'bibliographical control number (N) and accessionnumber (R) are not used at all with any operators. The causes of search failure are as follows. 1. The item was not used in the database. (15, 764 times : 79.42%). 2. The wrong search key was used. (3, 761 times : 18.95%) 3. The senseless string (garbage) was entered. (324 times : 1.63%) On the basis of these results, some recommendations are suggested to improve the search success rate as follows. First, a n.0, ppropriate user education and online help function let users retrieve LINNET OPAC more efficiently. Second, several corrections of retrieval software will decrease the search failure rate. Third, system offers right truncation by default to every search term. This methods will increase success rate but should considered carefully. By a n.0, pplying this method, the number of hit can be overnumbered, and system overhead can be occurred. Fourth, system offers special boolean operator by default to every keyword retrieval when user enters more than two words at a time. Fifth, system assists searchers to overcome the wrong typing of selecting key by automatic korean/english mode change.

• 한국음향학회지
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• 제19권7호
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• pp.42-47
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• 2000

본 논문에서는 DSP Group사의 16비트 고정 소수점 DSP(Digital Signal Processor)인 OakDSP Core를 사용하여 유럽의 이동통신에서 표준으로 사용되고 있는 음성 부호화기 알고리즘인 GSM-EFR (Global System for Mobile communications-Enhanced Full Rate)을 실시간으로 구현하였다. 실시간 구현된 GSM-EFR 음성 부호화기의 계산량은 약 24MIPS가 소요 되며, 7.06K 워드의 코드 메모리와 12.19K 워드의 데이터 메모리를 사용하였다. 구현된 음성 부호화기는 ETSI에서 제공하는 시험 벡터 샘플을 모두 통과하였으며, 객관적 평가툴을 이용하여 지각 평가를 수행한 결과, 32kbps ADPCM과 비슷한 음질을 보였다. 본 논문에서 실시간으로 구현된 GSM-EFR 음성 부호화기는 IMT2000 비동기 방식의 음성 부호화기 표준인 GSM-AMR의 최상위 전송률 모드로서, 앞으로 IMT-2000 비동기식 단말기용 모뎀 ASIC에 탑재할 GSM-AMR 음성 부호화기의 구현을 위한 기본 구조로 이용될 예정이다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 춘계종합학술대회
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• pp.389-393
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• 1999

디바이스 효율에 커다란 영향을 미치고 있는 임팩트이온화현상의 정확한 모델이 디바이스 시뮬레이션에 필수적인 요소가 되고 있다. 최근에는 정확한 GaAs 임팩트이온화 모델을 위해 각 에너지 범위에 파라서 7.8과 5.6의 지수를 갖는 수정된 Keldysh 공식이 사용되고 있다. 그러나 이 모델 또한 임팩트이온화의 방향성을 무시한 등방성 모델로서 저에너지에서 이방성을 보이는 임팩트이온화모델로서는 부적합하다. 임팩트이온화율은 낮은 전자에너지에서는 강한 이방성 성질을 나타내는 반면에, 임팩트이온화현상이 자주 발생하는 높은 에너지 범위에서는 등방성이 된다. 임팩트이온화율을 계산하기 위하여 Fermi 황금법칙과 의사 포텐셜방법에 의하여 계산된 full 에너지 밴드구조를 사용하였다. Form factor 및 실험값을 비교하였으며, 방향에 따른 전도대의 에너지 밴드 구조를 <100>, <110>, <111>의 방향에 대하여 조사하였다. 결과적으로, 임팩트이온화의 문턱에너지가 이방성을 갖음을 알 수 있었다. 또한 상대적으로 낮은 에너지 즉, 문턱에너지 근처에서 임팩트이온화율이 더욱 심하게 변화함을 알 수 있다.

• 한국약용작물학회지
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• 제20권5호
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• pp.320-330
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• 2012

This study was conducted to investigate the changes of chlorophyll contents, chlorophyll fluorescence, photosynthetic parameters, and leaf growth of Synurus deltoides under different shading treatments. S. deltoides was grown under non-treated (full sunlight) and three different shading conditions (Shaded 88~93%, 65~75%, and 45%~55%). Light compensation point ($L_{comp}$), dark respiration ($D_{resp}$), maximum photosynthesis rate ($Pn_{max}$), photo respiration rate ($P_{resp}$), carboxylation efficiency ($\Phi_{carb}$), and photochemical efficiency were decreased with increasing shading level; However, $CO_2$ compensation point ($CO_{2\;comp}$), total chlorophyll content, and specific leaf area (SLA) were shown the opposite trend. S. deltoides under 88~93% treatment showed the lowest photosynthetic activity such as maximum photosynthetic rate ($Pn_{max}$), photochemical efficiency, and $CO_2$ compensation point ($CO_{2\;comp}$). Therefore, photosynthetic activity will be sharply decreased with a long period of 8~12% of full sunlight. With the shading level decreased, carotenoid content and non-photochemical fluorescence quenching (NPQ) increased to prevent excessive light damage. This result suggested that growth and physiology of S. deltoides adapted to high light intensity through regulating its internal mechanism.

• 한국추진공학회지
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• 제9권4호
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• pp.1-8
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• 2005

과산화수소를 단일추진제로 사용하는 마이크로 추력기를 위한 실험적 연구를 수행하였다. 연구에서 은 촉매 활성화 방법과 메조스케일 반응기의 성능평가에 관한 실험을 하였다. 시도한 여러 가지 활성 방법 중, $500^{\circ}C$의 수소 환원법의 경우 가장 좋은 반응성을 가짐을 확인 하였다. 추진제의 완전한 분해 조건을 찾기 위해 메조스케일 반응기가 제작되었다. 촉매 베드를 위해 지지체로 20 mm 길이의 유리 웨이퍼를 준비하여 은 촉매를 스퍼터링 하였다. 과산화수소 공급 유량에 따라 반응기내 공간시간이 변하므로 유량을 변화시키며 반웅기 실험을 수행하였고 전환율을 측정 하였다. 20 mm 베드 길이에서 추진제의 완전한 분해를 위해 480초 이상의 공간시간이 요구된다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권4호
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• pp.303-317
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• 2013

Two novel clocking strategies for a high-speed multi-channel serializer-deserializer (SERDES) are proposed in this paper. Both of the clocking strategies are based on groups, which facilitate flexibility and expansibility of the SERDES. One clocking strategy is applicable to moderate parallel I/O cases, such as high density, short distance, consistent media, high temperature variation, which is used for the serializer array. Each group within the strategy consists of a full-rate phase-locked loop (PLL), a full-rate delay-locked loop (DLL), and two fixed phase alignment (FPA) techniques. The other is applicable to more awful I/O cases such as higher speed, longer distance, inconsistent media, serious crosstalk, which is used for the deserializer array. Each group within the strategy is composed of a PLL and two DLLs. Moreover, a half-rate version is chosen to realize the desired function of 1:2 deserializer. Based on the proposed clocking strategies, two representative ICs for each group of SERDES are designed and fabricated in a standard $0.18{\mu}m$ CMOS technology. Measurement results indicate that the two SERDES ICs can work properly accompanied with their corresponding clocking strategies.

• 한국전산구조공학회논문집
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• 제20권2호
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• pp.207-216
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• 2007

본 논문에서는 볼트로 체결된 강재 조립 합성보의 휨거동에 대한 유한요소해석을 통하여 휨거동 특성을 분석하였다. 두개의 강재보가 볼트로 체결되어 횡하중을 받을 때 발생하는 볼트의 합성효과, 강판사이의 마찰특성을 고려하였다. 체결에 사용된 볼트의 갯수 및 마찰계수의 변화에 따른 변위, 휨응력 그리고 전단응력을 쉘 요소를 사용한 유한요소해석에 의해 계산하였다. 이런 결과들은 완전 비합성보, 부분 합성보와 완전 합성보의 해석치와 비교되었다. 해석결과 합성보의 거동은 강재의 마찰보다 볼트의 갯수로 표현되는 합성률에 크게 영향을 받았다. 합성률이 $50{\sim}60%$에 도달할 때 합성보의 거동은 완전 합성보와 유사함을 보였다.

• 한국약용작물학회지
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• 제21권5호
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• pp.394-400
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• 2013

This study was carried out in order to examine the germination characteristics of Atractylodes japonica seeds, and it was to develop the more efficient pre-treatment and production system of the seeds. Experiment was performed by two ways-temperature control (10, 15, 20, $25^{\circ}C$) and shading treatment (full sunlight, 35, 50, 75, 95% of full sunlight). Seed pre-treatment before the each experiment was carried out by temperature (with low temperature and wetting treatment (LTW) for 0, 15, 30, 45 and 60 days) and shading treatment (with drying at room temperature (DRT), drying at low temperature (DLT) and water soaking (WS) for 48 hours). Seeds of A. japonica were germinated well under temperature control (overall 85.3~100%), especially high temperature. And, the seeds pre-treated with LTW for 45 days germinated with a 100% success rate. Under the surveying shading treatment, the highest germination rate was 95.8% with DRT and overall 63.2~95.8%. Germination rate under seeds with WS was 63.2~7.8%. As a result of surveying the whole experiment, A. japonica seeds don't need to pre-treat cause of high germination, but if it is performed with LTW for a certain period of time, it would be more productive.

• 대한영양사협회학술지
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• 제14권4호
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• pp.361-370
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• 2008

The purpose of this study is to provide basic data for the medical nutrition therapy of premature infants. The general characteristics, presence of metabolic disorders, hematological profile and feeding methods were compared between the premature infant group (<37 weeks, n=61) and the full-term infant group (37$\sim$42 weeks, n=165). Birth weight (p<0.0001), birth length (p<0.005), head circumference (p<0.0001), chest circumference (p<0.0001), and Apgar scores (p<0.0001) of the neonates were all statistically lower in the premature infant group. Jaundice cases (p<0.0001) were statistically higher in the premature infant group. White blood cell counts (WBC: p<0.005), mean corpuscular volume (MCV: p<0001), mean corpuscular hemoglobin (MCH: p<0.005), mean corpuscular hemoglobin concentration (MCHC: p<0.005), and mean platelet volume (MPV: p<0.05) were statistically lower in the premature infant group. The premature infant group were fed a higher rate of premature formula than breast milk and the full-term infant group were fed a high rate of human milk at a higher rate, showing differences in kinds of feeding methods (p<0.0001) between the two groups. An infant's birth weight showed a significantly positive correlation with the infant's birth length (p<0.0001), head circumference (p<0.0001), chest circumference (p<0.0001), and Apgar scores(p<0.0001). The birth length also showed a significantly positive correlation with both head circumference (p<0.05) and chest circumference (p<0.05). Head circumference showed a significantly positive correlation with chest circumference (p<0.0001) and Apgar scores (p<0.0001). Chest circumference showed a significantly positive correlation with Apgar scores (p<0.0001). In addition, the Apgar Score at of 1 minute after birth showed a significantly positive correlation with the Apgar score at of 5 minute after birth (p<0.0001).

• Plant Biotechnology Reports
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• 제3권3호
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• pp.259-266
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• 2009

A plantlet regeneration protocol was developed on pot-grown mature plants of Elaeocarpus robustus Roxb. cv. Dwarf from nodal and leaf explants. The best yield of adventitious shoots was achieved from the leaf-derived calli in a modified MS ($MMS_1$, half strength of major salts, full strength of minor salts, and vitamins) medium containing $4.0{\mu}M$ BA + $4.0{\mu}M$ Kn + $0.5{\mu}M$ NAA + 15% coconut water (CW). The shoot multiplication rate was amplified about twofold per culture after the addition of 15% CW to the medium. The rate of shoot multiplication reached maximum at the 5th subculture, and it maintained this rate throughout the 3 subsequent subcultures. The best rooting in vitro was investigated by subculturing the microcuttings in an $MMS_2$ (half strength of both major salts and minor salts and full strength of vitamins) medium containing $1.0{\mu}M$ IBA in the dark for one initial week at $30^{\circ}C$, followed by subculturing them in a plant-growth regulator (PGR)-free medium in the light. The plantlets raised in vitro were successfully established under ex vitro conditions.