• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.556-561
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• 2005

The steel shows plastic deformation after the yield point exceeds. The plastic deformation due to overloads occurs at the interior support of a continuous bridge. The plastic deformation is concentrated at the interior support and the permanence deformation at the interior support remains after loads apply. Because local yielding causes the positive moment at the interior support, it is called 'auto-moment'. Auto-moment redistributes the elastic moment. Because of redistribution, auto-moment decreases the negative moment at the interior support of a continuous bridge. In this paper, the plastic rotation is evaluated using the moment-rotation curve proposed by Schalling and Beam-line method. Moreover, auto-moment is derived from the experiment curve.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.443-446
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• 1997

This paper raises issues in testing the absorption coefficients of sound-absorptive samples in the standing wave tube according to the Korean standard of KS F 2814. The code does not consider any effect of air-damping during test. This limitation has been shown to yield much variation of sound absorption coefficients for recent sample tests whose coefficients are less than 10 %. An improved method of calculating the sound absorption coefficients is proposed in this work and its effectiveness in real test is also illustrated. Finally, the guide line for the modification of our national standard code KS F 2814 is suggested for the future.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.33-40
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• 1998

Although a structural analysis based on e linear elastic theory yields good results for deformations and stresses produced by working loads, it fails to assess the teal load-carrying of the plates on the verge of yielding. In case of a limit analysis of plates, the yield line theory is widely used on the basis of the upper bound theorem and theoretically it overestimates the strength of the plate. There is, therefore, a general need for analytical methods of predicting the inelastic behavior and load-carrying capacities of plate subjected to arbitrary loadings and boundary conditions. The $\rho$-version of finite element method has been presented for determining the accurate limit load of plates. The numerical results by $\rho$-version model compares with the results obtained by the h-version software ADINA as well as with the available analytical solutions in literatures.

• 대한조선학회지
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• 제21권2호
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• pp.35-42
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• 1984

A line integral is exhibited which has the same value for all paths surrounding the tip of crack in a two dimensional strain field of elastic-plasticc material. Finite element method was used to determine Rice's J-integral value in centrally cracked plate. These numerical J-integral values were compared with corresponding values of reference with low hardening and high yield strength. The J-integral value was also computed for a crack extension and different load condition. For increasing crack length the value of J-integral also increases, this means that the crack is unstable. To prove path independent, three paths were used in the analysis and proved.

• 한국정밀공학회지
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• 제13권3호
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• pp.80-93
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• 1996

A 2-dimensional FEM/GEM program was developed under the plane strain assumption using linear line elements for analyzing stretch/draw forming operations of an arbitrarily shaped draw-die. FEM formulation adopted a new algorithm for solving force equilibrium as well as non-penetration condition simultaneously. Also, a rigid-viscoplastic material model with Hill's normal anisotropic yield condition and rate-sensitive hardening law is assumed, along with the Coulomb friction law in the contact regions. For the case of numerical divergence at nearly final forming stages, geometric force equilibrium method(GEM) is also introduced. The developed program was tested by simulating the forming processes of cylindrical punch/open die, and the drawing processes of automotive oilpan and hood inner panel in order to verify the usefulness and validity of FEM/GEM formulation. The numerical simulation verified the validity and robustness of developed program.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1992년도 학술논문발표회 논문집 제11권 1호
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• pp.23-28
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• 1992

The purpose of this paper is to develop a new adaptive echo canceller improving convergence speed and near-end-talker detection performance of the conventional echo canceller. In a conventional adaptive echo canceller, an adaptive digital filter with TDL(Tapped-Delay Line) structure modelling the echo path uses the LMS(Least Mean Square) algorithm to cote the coefficients, and NET detector using energy comparison method prevents the adaptive digital filter to update the coefficients during the periods of the NET signal presence. The convergence speed of the LMS algorithm depends on the eigenvalue spread ratio of the reference signal and NET detector using the energy comparison method yields poor detection performance if the magnitude of the NET signal is small. This paper presents a new adaptive echo canceller which uses the pre-whitening filter to improve the convergence speed of the LMS algorithm. The pre-whitening filter is realized by using a low-order lattice predictor. Also, a new NET signal detection algorithm is presented, where the start point of the NET signal is detected by computing the cross-correlation coefficient between the primary input and the ADF(Adaptive Digital Filter) output while the end point is detected by using the energy comparison method. The simulation results show that the convergence speed of the proposed adaptive echo canceller is faster than that of the conventional echo canceller and the cross-correlation coefficient yield more accurate detection of the start point of the NET signal.

• Journal of Positioning, Navigation, and Timing
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• 제5권1호
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• pp.1-9
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• 2016

Range-based wireless localization system must measure accurate range between a mobile node (MN) and reference nodes. However, non-line-of-sight (NLOS) error caused by the spatial structures disturbs the localization system obtaining the accurate range measurements. Localization methods using the range measurements including NLOS error yield large localization error. But filter-based localization methods can provide comparatively accurate location solution. Motivated by the accuracy of the filter-based localization method, a filter residual-based NLOS error estimation method is presented in this paper. Range measurement-based residual contains NLOS error. By considering this factor with NLOS error properties, NLOS error is mitigated. Also a process noise covariance matrix tuning method is presented to reduce the time-delay estimation error caused by the single dynamic model-based filter when the speed or moving direction of a MN changes, that is the used dynamic model is not fit the current dynamic of a MN. The presented methods are evaluated by simulation allowing direct comparison between different localization methods. The simulation results show that the presented filter is more accurate than the iterative least squares- and extended Kalman filter-based localization methods.

• 한국농공학회지
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• 제31권2호
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• pp.82-91
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• 1989

This study was carried out to get the basic information of irrigation plans for the red pepper, such as optimum irrigation level and irrigation requirement in Taegu and Kyungpook province. In this study, red peppers were cultivated in 6 PVC pot lysimeters filled with 60cm deep clay loam soil. Four tensiometers were installed in each plot to measure the soil water pressure head. Field measurements were made during the period June 6 to October 31, 1988 at the experimental farm of Kvungpook National University. Six levels of irrigation were used. They were PF 1.8-2.0, PF 2.2-2.4, PF 2.8-3.0, FC-PF.1.7, FC-PF 2.2, and FC-PF 2.7. The results obtained from this study are summarized as follows : 1. In case of irrigation levels of narrow ranges of water contents, the higher the soil water content was, the larger the ET was. Hut in case of the irrigation levels returning to the field capacity, the lager the PF value of irrigation point was, the larger the ET was. Considering ET, yield and weight per fruit, the latter is much better than the former irrigation method. 2. The mean daily ET and mean ET ratio for each 10-day period showed that the maximum value occured in the last of August. The ranges of those were 3.74-14.64 mm/day and 0.87-3.40, respectively. These values showed that small during the early stage of growth, large during the middle stage and getting smaller in the last stage. 3. In case of irrigation levels of narrow ranges of water contents, the increase of irrigation water supplied increased the ET. The relationship between the two showed nearly straight line. Most of irrigated water was consumed as ET and the rest as percolation. But, in case of irrigation levels returning to the field capacity, the higher the PF value of irrigation point was, the larger the ET ratio was. However, their relationship didn't show straight line. 4. The irrigation level of PC - PP 2.7 was found to be the optimum irrigation level with respect to the yield, the weight per fruit, stem length, irrigation requirement and percolation quantity. In this case, mean daily ET and mean ET ratio were 6.79 mm/day (total 10052 mm) and 1.67, respectively. The maximum mean daily ET and mean ET ratio for 10-day period were 14.64 mm/day and 3.40, respectively, in the last of August, and the maximum daily ET was 2126 mm/day on August 24. 5. In case of PC - PP 2.7 which is found the optimum irrigation level, mean irrigation water required, mean ET and mean percolation water quantity were 7.44 mm/day, 6.79 mm/day(91.3% of irrigation water), and 0.38 mm/day (5.5% of it), respectively.

• 한국육종학회지
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• 제40권4호
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• pp.512-516
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• 2008

'조양'은 우리나라에서 재배가 가능한 조숙 양질 다수성 쌀귀리 품종을 육성하고자 1996년에 조숙성인 '식용귀리'를 모본으로 조숙 대립 겉귀리 계통인 '귀리23호'를 부본으로 인공교배를 하여 계통육종법에 의해 선발된 'SO96025-B-303-44-2-5' 계통이다. 이 계통은 2003년부터 생산력검정시험을 거쳐 계통명이 '귀리57호'로 명명되었고, 2005년부터 지역적응시험을 거쳐 207년에 육성된 품종이며, 그 특성은 다음과 같다. 1. '조양'은 잎색이 농녹색이고 잎폭은 중간 정도이며, 이삭형은 산수형이고, 종실은 길고 담황색이다. 2. '조양'의 출수기는 재배지 3개년 평균 4월 28일로서, 기존에 육성된 선양에 비해 11일 빨랐으며, 지역적응시험에서의 평균 종실 수량은 4,670 kg/ha으로 표준품종인 '선양'보다 38% 많았다. 4. '조양'은 '선양'에 비해 탈부율과 조단백질 함량이 12.9%로 높고, 베타글루캔 함량은 4.7%로서 표준품종인 '선양'과 비슷하였다.

• Applied Biological Chemistry
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• 제25권4호
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• pp.232-238
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• 1982

농가포장(農家圃場)(13개소(個所))에서 중질소비시험결과(重窒素肥試驗結果) 80%의 포장(圃場)에서 이용율(利用率)은 감법(減法)의 경우가 표식법(標識法)의 경우보다 높았으며 비료질소(肥料窒素)에 의(依)한 토양질소흡수(土壤窒素吸收)가 조장(助長)된 것을 나타낸다. 이 두 방법(方法)의 값은 포장간(圃場間)에에 류사(類似)한 경향(傾向)을 보였다. 황피뇨소(黃皮尿素)와 국지시용(局地施用)은 시비효율(施肥效率)(시비질소(施肥窒素) 당증수량(當增收量), Fe)을 분시(分施)의 15에서 23으로 증대(增大)시켰는데 이는 이용율(利用率)(Ef)을 29에서 50으로 증대시킨 때문이며 흡수시비질소효율(吸收施肥窒素效率)(Ef)은 50에서 46으로 감소하는 경향(傾向)을 보였다. 통일계(統一系)의 다수확능(多收穫能)은 흡수시비질소효율(吸收施肥窒素效率), 전이율(轉移率) 및 토양질소선호지수(土壤窒素選好指數)(시비질소흡수증가량(施肥窒素吸收增加量)에 대(對)한 토양질소흡수증가량(土壤窒素吸收增加量)의 비(比) PI)가 큰데 기인한 것 같다. 일련의 본(本) 연구(硏究)는 시비체계하(施肥體系下)의 수량(收量)은 이용율(利用率)과 흡수시비질소효율(吸收施肥窒素效率)의 적(積)인 시비효율(施肥效率)에 의존(依存)하며 비료(肥料)의 형태(形態)나 시비시기(施肥時期) 및 방법(方法) 등(方法) 시비관리(施肥管理)는 주(主)로 이용율(利用率)을 증대(增大)시키고 이용율(利用率)의 한계(限界)는 품종(品種) 특성(特性)에 주(主)로 기인(基因)하는 흡수시비질소효율(吸收施肥窒素效率)에 의(依)하여 조정(調整)됨을 보였다.