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        검색결과 45

        21.
        2003.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Databases are central to business information systems and RDBMS is most widely used for the database system. Normalization was designed to control various anomalies (insert, update, delete anomalies). However, normalized database design does not account f
        4,000원
        22.
        2002.10 구독 인증기관 무료, 개인회원 유료
        Databases are central to business information systems and RDBMS is most widely used for the database system. Normalization was designed to control various anomalies (insert, update, delete anomalies). However, normalized database design does not account for the tradeoffs necessary for performance. In this research, we model a database design method considering denormalization of duplicating attributes in order to reduce frequent join processes. This model considers response time for processing each select, insert, update, delete transaction, and for treating anomalies. A branch and bound method is proposed for this model.
        4,000원
        23.
        2002.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        24.
        2001.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        상부벽식-하부골조구조(복합구조)는 상.하부 구조물의 서로 다른 구조형식으로 인해 전이층 부근에서 질량 및 강성의 큰 차이를 보인다. 이러한 복합구조의 특징은 일반적으로 강성, 질량 및 기하학적 수직 비정형성을 갖게 된다. 본 연구에서는 복합구조물의 상부층수가 변화하는 네 가지 해석모델을 선정하여 탄소성 정적 및 동적 해석을 수행하고 해석결과를 통해 구조물의 탄소성 응답특성을 살펴보고자 한다. 본 연구의 결론은 다음과 같다. 1) 탄소성 정적해석에서는 하부골조 구조의 보와기둥의 항복힌지가 상부벽식구조의 층수 변화에 상관없이 전 모델에 걸쳐 비슷한 크기의 설계용 밑면전단력에서 항복이 발생되었고 그 분포 또한 비슷하였다. 그러나 상부벽식구조의 경우 전단벽이 고층화될수록 coupling beam에서 설계용 밑면전단력 V에 대해서도 휨항복한지가 발생되었다. 2) 탄소성 동적해석으로부터는 하부골조의 일부층의 보는 55gal의 작은 지진동에서 소성이 발생되었고 상부벽식구조의 경우 coupling beam과 전이층 상부의 전단벽에서 소성변형이 집중되었다. 3) 탄소성 해석으로부터 상부벽식구조의 층수가 낮아질수록 하부골조구조의 층강성이 상대적으로 줄어들게 되어 하부골조에서 연약층(soft story) 현상이 나타났다.
        4,200원
        25.
        1999.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문의 목적은 탄소성 지진 응답해석을 수행하여 고층 벽식 아파트의 내진성능을 평가하는 것이다 먼저 구조물을 3차원 입체 모델화 하여 정적 탄소성 해석을 수행하고 층강성 및 항복 충전단력을 평가한 후 그 결과를 이용하여 집준 질량계 모델을 사용한 시간 이력 지진 응답해석을 수행한다 탄소성 이력 모델로는 bi-linear 모델 및 Clough 모델을 입력 지진동파형으로는 4종류의 기록 지진동 띠 Centro 1940 NS, Taft 1952 EW Hachinohe 1968 NSm Kobe 1995 NS를 사용하고 입력 지진동의 강도는 최대 지반속도치 12Kine이 되도록 크기를 조절하여 입력한다 탄소성 지진응답 해석결과 고층 벽식 아파트는 진도 5정도의 지진동 크기에서 전층에소성 변형이 발생하여 취약한 내진성능을 보여준다.
        4,000원
        26.
        1997.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 집중 질량 구조물의 천이응답에 대한 시간영역 민감도 해석의 기본 개념을 설명한다. 외부 가진에 따른 구조물의 응답에 미치는 설계변수 변화의 영향을 구하기 위해 시간영역 민감도 함수를 구하는 방법을 제시하였다. 시간영역에서 구조물의 설계변수 민감도는 1차 표준 민감도 함수와 백분율 민감도 함수를 통해 확인하였다. 이러한 민감도 함수와 그 계산은 설계변수에 대한 시스템 상태변수의 편미분에 의한 것이다. 또한, 직접 미분법에 의한 해석적 방법의 편미분 결과와 수치적 방법에 의한 결과를 비교하였다.
        4,000원
        27.
        1989.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experiment 'was conducted to investigate the grazing cattle's palatability by the method of grazing time on the pasture dominated orchardgrass and on the pasture dominated perennial ryegrass from June to October, 1987. The experiment was carried out
        4,000원
        28.
        1985.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        파종기(播種期) 이동(移動)에 따른 사일리지용 옥수수의 생장반응(生長反應)을 알아 보고자 1980년(年) 4월(月) 25일(日)부터 6월(月) 24일(日)까지 12일(日) 간격(間隔)으로 6회(回)의 파종기(播種期)를 두고 축산시험장(畜産試驗場) 사료포장(飼料圃場)에서 조생종(早生種) MTC-1과 만생종(晩生種) 수원(水原) 19호(號)를 가지고 시험(試驗)한 결과(結果)는 아래와 같다. 1. 파종기(播種期)가 늦어질수록 출현일수(出現日數)는 단축(短縮
        4,000원
        29.
        2019.08 KCI 등재 서비스 종료(열람 제한)
        『네 사중주』의 주제는 매우 단순하다. 그것은 인간과 하나님 사이의 바람직한 관계설정으로 요약된다. 간단한 주제임에도 불구하고 『네 사중주』의 핵심 내용을 파악하기란 결코 쉽지 않다. 그 어려움 중의 하나가 시간에 대한 엘리엇의 정의이다. 엘리엇은 시간을 우리가 생활기준으로 삼는 물리적 기준과는 달리 형이상학적으로 정의한다. 그는 물리적 시간에 익숙한 인간에게 시간에서 해방되는 방법으로서 하나님의 시간에 인간의 그것을 맞출 것을 제안한다. 이것이 곧 과거, 현재, 미래에서 해방되어 무시간에 접근할 수 있는 방법이라 할 수 있다. 그러나 인간은 이를 부인하고 시간을 물리적이나 과학적으로 측정하려고 애쓴다. 그 결과 하나님이 아닌 다른 일종의 점술 행위에 의존함으로써 구원에 이르지 못한다.
        30.
        2017.04 서비스 종료(열람 제한)
        This paper aims to develop a wireless unified-maintenance system(WUMS) to obtain real-time structural response of civil structures. The WUMS integrates the GPS module, the strain module and the acceleration module based on the standalone controller, and includes the RF module for remote measurement and the battery for long term operation. In order to evaluate the performance of the WUMS, a response test using a modal shaker and a modal test using a model bridge were performed. The test results using USMS were compared with those measured by wired system. Finally, the developed WUMS was appropriate to obtain the structural response of the civil structure in real-time, unified, and wirelessly.
        31.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        This paper aims to develop a wireless unified-maintenance system(WUMS) to obtain real-time structural response of civil structures. The WUMS integrates the GPS module, the strain module and the acceleration module based on the standalone controller, and includes the RF module for remote measurement and the battery for long term operation. In order to evaluate the performance of the WUMS, a response test using a modal shaker and a modal test using a model bridge were performed. The test results using USMS were compared with those measured by wired system. Finally, the developed WUMS was appropriate to obtain the structural response of the civil structure in real-time, unified, and wirelessly.
        32.
        2016.10 서비스 종료(열람 제한)
        Extended Accumulated SIBIE in order to improve the limit of visibility of Accumulated SIBIE method is a method to significantly improve the performance of measurements by extension the region of visibility to a low-frequency region. Decrease of resonant frequency displayed in the lower frequency region than the thickness frequency is due to reduction in rigidity by essentially degradation and cross-sectional loss of members. It is necessary to clarify the relationship between the resonance frequency and the deterioration or damage patterns to learn these patterns. In this research, by obtaining the vibration mode and the natural frequency by the eigenvalue analysis, it was confirmed that dynamic analysis which take time and effort can be minimized.
        33.
        2016.08 KCI 등재 서비스 종료(열람 제한)
        Purpose: Introduction of the LEGO Mindstorms EV3 as a low cost research tool for various studies and to show how study tools could be built using the LEGO with ease. Methods: To show what the LEGO Mindstorms EV3 could do for studies, programming method was described and some example devices used previous papers were reconstructed; EX1 - Selection of left right device for Stoet(2010), EX2 - Time expectation device for Kim and Ryu(2015), and EX3 - Four digits random number generator for Huh and Lee(2015). Time delay of each example device was tested to evaluate effectiveness of the LEGO Mindstorms EV3 as research device. Results: Combination of single execution structure and button switch on the EV3 brick showed 1 ms error of time measurement, and combination of single execution structure and touch sensor showed 10 ms error of time measurement. 1 ms error of time measurement is same accuracy achieved by Windows based computer system.
        34.
        2015.11 KCI 등재 서비스 종료(열람 제한)
        Purpose: The purpose of this study was to determine whether yaw head rotational reaction time and premotor time to visual stimuli in central and peripheral visual fields would improve with practice. Method: The task was to make a complete horizontal head rotation regardless of target eccentricity in two response conditions: TOWARD and AWAY conditions. In the TOWARD condition subjects rotated their head in the direction ipsilateral to target appearance for a congruent S-R response. In the AWAY condition subjects rotated their head contralateral to target appearance for an incongruent S-R response. All subjects participated in the following sequence of testing and training: (1) Pre-test, (2) Training (6 days over 2 weeks), and (3) Post-test. Measures associated with yaw head rotations involved with reaction time, premotor time and electromechanical delay. Results: Results revealed shorter yaw head rotation RT in TOWARD and AWAY conditions after 6 days of practice in TOWARD and AWAY conditions. We found the greater observations especially for the centrally placed target. Conclusion: These results suggest greater performance improvements were observed for most subjects when practice and testing were within the same condition, indicating support for the well-known learning specificity phenomena.
        35.
        2014.10 서비스 종료(열람 제한)
        Although accelerators can be utilized for the prevention of early frost by developing the strength of concrete in cold weather, no security of workability occurs because early hydration makes them react rapidly. In this study, granulation was used as a method as it can control the response time of the accelerator to secure the workability of fresh concrete.
        36.
        2009.08 KCI 등재 서비스 종료(열람 제한)
        본 연구의 목적은 장기간 저항운동 강도별 스트레스를 지칭하는 호르몬의 분비 차이를 제시하는 것이며, 타 연구 논의의 차별화로 배제된 심리적 관련 변인을 기술하였다. 연구대상은 C 대학교 남자대학생 17명으로 최대하 및 최대운동 강도별로 각각 6주간의 저항운동 실시 후 네 시점별 성장호르몬과 테스토스테론 및 코르티솔의 차이 결과, 남성호르몬을 제외한 성장 및 코르티솔 변화는 안정시에 비해 운동직후 유의하게 증가하였으며, 6주 전후 변화는 코르티솔만이 네 시점별 유의한 증가가 있었다. 분비 차이의 의미로, 성장호르몬 증가는 운동 강도별 모두 유의하게 증가하였으며, 남성호르몬은 유의한 변화가 없었으며, 최대강도 운동의 경우 코르티솔은 6주 후 평소 안정 시에도 증가되어 있었다. 장기간 운동처치의 생리적인 결과 해석에 심리적 변화를 고려하여야 하며 부정적인 스트레스로 변환되지 않도록 심리적인 여러 변인 연구가 병행되어야 하겠다.
        37.
        2008.06 KCI 등재 서비스 종료(열람 제한)
        Gene-expression analysis is increasingly important in biological research, with real-time reverse PCR (RTPCR) becoming the method of choice for high-throughput and accurate expression profiling of selected genes. However, this technique requires important preliminary work for standardizing and optimizing the many parameters involved in the analysis. Plant stress studies are more and more based on gene expression. The analysis of gene expression requires sensitive and reproducible measurements for specific mRNA sequence. Several genes are regulated in response to abitoic stresses, such as salinity, and their gene products function in stress response and tolerance. The design of the primers and TaqMan probes for real-time PCR assays were carried out using the Primer ExpressTM software 3.0. The PCR efficiency was estimated through the linear regression of the dilution curve. To understand the expression pattern of various genes under salt stressed condition, we have developed a unique public resource of 9 stress-related genes in poplar. In this study, real-time RT-PCR was used to quantify the transcript level of 10 genes (9 stress-related genes and 1 house keeping gene) that could play a role in adaptation of Populus davidiana. Real-time RT-PCR analyses exhibited different expression ratios of related genes. The data obtained showed that determination of mRNA levels could constitute a new approach to study the stress response of P. davidiana after adaptation during growth in salinity condition.
        38.
        2006.05 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 자료수집과 적용에 상당한 시간과 노력이 요구되는 기존의 수치모형들 대신에 최소한의 유역정보를 이용해 오염물질의 이동시간과 확산을 예측할 수 있는 방법을 제시하고자 하였다. 즉, 하천에서 오염물질의 이동속도, 시간에 따른 오염물질의 첨두농도, 오염물질이 하천의 한 점을 통과하는데 소요되는 시간장경 등의 요소들을 이용한 단위오염도의 개념을 도입하였으며, 이들 요소들의 추정을 위해서는 미국 내의 수많은 하천을 대상으로 개발된 회귀방정식을 이용하
        39.
        2002.09 KCI 등재 서비스 종료(열람 제한)
        Planting date of soybeans [Glycine max (L.) Merr.] is one of production components in cultural systems. The objective of the current study was to identify the components of soybean production and cultural practices encompassing planting dates and cultivars that respond to dry matter accumulation, harvest index and yield components. Three determinate soybean cultivars were planted on May 13 (early), June 3 (mid), and June 24 (late). Planting density was 60~times 15cm with 2 seeds (222,000 plants per ha). Soybean plants were sampled every 10 days interval from the growth stages of V5 to R8 and separated into leaves including petioles, stems, pods, and seeds. Dry matter accumulations, harvest indices, and yield components were measured. Early planting had taken 55 days from VE to R2 and late planting taken 39 days indicating reduced vegetative growth. Early planting showed higher leaf, stem, pod and seed dry weights than late planting. However, late planting appeared to be higher harvest index and harvesting rate. Vegetative mass including leaf and stem increased to a maximum around R4/R5 and total dry weight increased to a maximum around R5/R6 and then declined slightly at R8. The highest seed yield was obtained with mid planting and no difference was found between early and late plantings. Cultivar differences were found among planting dates on growth characteristics and yield components. The results of this experiment indicated that soybean yield in relation to planting dates examined was mainly associated with harvest index and harvesting rate, and planting date of cultivars would be considered soybean plants to reach the growth stage of R4/R5 after mid August for adequate seed yield.
        40.
        2002.09 KCI 등재 서비스 종료(열람 제한)
        Seedling establishment of soybean [Glycine max (L.) Merr.] is a critical factor in production system and cultural practices. The objective of this study was to identify the components of soybean seedling developments encompassing planting dates and cultivars that respond to emergence, early growth stage and dry matter accumulation. Three soybean cultivars, Hwangkeumkong, Shinpaldalkong 2, and Pungsannamulkong, were planted at Baegsan silty loam soil. Planting date was May 13, June 3, and June 24 in 2001. Sprinkler irrigation was accompanied with 30mm after seeding for three planting dates. Soybean seedlings were sampled at the growth stages from VE to V5. Days to emergence of soybean seedlings were taken 8 at May 13 and 5 at June 24 plantings. Emergence percentage was over 90 at three planting dates. May 13 planting took 33 days and June 24 planting was 25 days for reaching V5 growth stage. Cotyledon number was decreased after V2. Significant cultivar difference was found in cotyledon dry weight until V2 which differed in seed dry weights at the planting times. Leaf and total dry weights of soybean seedlings were not differed from V1 to V3 among planting dates and cultivars. Leaf water contents were generally ranged 78 to 85%. Branch was appeared from V4. Leaf/stem ratio among cultivars was similar at five growth stages and gradually increased from 2.1 at V1 to 2.8 at V5. The results based on this experiment indicated that seedling establishment of soybean was continued from VE to V3 growth stages affecting mainly by planting date and soil moisture.
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