• 한국식품영양과학회지
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• 제34권3호
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• pp.403-407
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• 2005

구기자의 기능성을 지닌 케이크의 제조를 위해서 밀가루의 4%, 0%, 12%, 16%, 20%를 구기자 분말로 대체한 후에, 케이크의 물리적, 관능적 특성을 조사하였다. 또한 저장기간 동안의 케이크의 경도와 수분함량의 변화를 측정하여, 케이크의 품질변화에 미치는 영향을 검토하였다. 구기자 함량이 12%, 16%, 20%인 반죽의 비중은 유의성 있게 감소하였지만, 케이크의 비 체적은 20% 첨가구를 제외하고는 차이를 나타내지 않았다. 껍질색은 구기자의 첨가량이 증가함에 따라 갈색이 진해지괴 어두워졌으며, 내부색은 첨가량이 증가함에 따라 어둡고 주황색이 진해졌다. 구기자를 4%, 8% 함유한 케이크는 촉촉함과 부드러움성, 기호도에서 대조구와 차이가 없는 것으로 평가되어 케이크에 대한 구기자 분말의 최적 대체비율은 4-8%로 나타났다.

• Steel and Composite Structures
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• 제34권1호
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• pp.123-139
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• 2020

The tube outward local buckling of Concrete-Filled Steel Tube (CFST) beam under high compression stress is still considered a critical problem, especially for steel tubes with a slender section compared to semi-compact and compact sections. In this study, the flexural performance of stiffened slender cold-formed square tube beams filled with normal concrete was investigated. Fourteen (14) simply supported CFST specimens were tested under static bending loads, stiffened with different shapes and numbers of steel stiffeners that were provided at the inner sides of the tubes. Additional finite element (FE) CFST models were developed to further investigate the influence of using internal stiffeners with varied thickness. The results of tests and FE analyses indicated that the onset of local buckling, that occurs at the top half of the stiffened CFST beam's cross-section at mid-span was substantially restricted to a smaller region. Generally, it was also observed that, due to increased steel area provided by the stiffeners, the bending capacity, flexural stiffness and energy absorption index of the stiffened beams were significantly improved. The average bending capacity and the initial flexural stiffness of the stiffened specimens for the various shapes, single stiffener situations have increased of about 25% and 39%, respectively. These improvements went up to 45% and 60%, for the double stiffeners situations. Moreover, the bending capacity and the flexural stiffness values obtained from the experimental tests and FE analyses validated well with the values computed from equations of the existing standards.

• 대한기계학회논문집A
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• 제28권5호
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• pp.489-494
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• 2004

Long Period Gratings (LPG) is currently receiving considerable attention because of their consistent measuring results fur pressure, temperature, strain and flow. LPG is easier to prepare and has a high sensitivity compared with Fiber Bragg Gratings (FBG). In addition, this kind of optical fiber sensors could be used for implementations in various structures. In this paper, LPG was used to monitor in situ the resin flow and the curing process in VARTM (Vacuum Assisted Resin Transfer. Molding). In order to demonstrate the effectiveness of the method, FBG is inserted into the glass mat to monitor the resin flow using optical spectrum analyzer (OSA). The curing reactions in VARTM are also observed using the same method. From the results, the attenuation wavelength shift and the loss change of attenuation band can be obtained from the status of the RTM (Resin Transfer Molding) sample owing to the internal variations of the .effective index, temperature, and pressure. It is shown that the proposed LPG is more effective in monitoring the curing reaction than FBG.

• 한국응용곤충학회지
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• 제51권4호
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• pp.331-342
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• 2012

본 연구는 먹이식물과 흡밀식물의 수 그리고 식생이 나비의 개체수 및 다양성에 미치는 영향을 조사하기 위하여 2008-09년까지 충북 보은군 속리산 법주사 지역을 4개 구간으로 나누어 모니터링을 실시하였으며 이를 단순회귀분석 및 다중회귀분석하였다. 그 결과 나비 개체수와 식물종수, 흡밀식물 그리고 먹이식물 수를 다중회귀분석 한 결과에서 상관관계를 보였으며, 서식지 면적이 클수록 개체수는 많아지는 것으로 나타났다. 그러나 단순회귀 분석 시 나비의 종수와 다양도지수는 먹이식물 수 및 구간면적과 각각 낮은 상관관계를 나타냈다. 또한 보다 다양한 식생을 보이는 구간에서 나비 종수가 증가하였다. 나비의 다양성과 개체군 보전을 위해서는 다양한 수종의 식물과 함께 나비의 먹이식물과 흡밀식물이 복합적으로 분포하고, 식생은 각각의 요소들이 서로 보완관계를 유지할 수 있도록 다른 형태로 존재하는 것이 필요함을 시사한다.

• Steel and Composite Structures
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• 제20권2호
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• pp.227-249
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• 2016

The objective of this work is to present a zeroth-order shear deformation theory for free vibration analysis of functionally graded (FG) nanoscale plates resting on elastic foundation. The model takes into consideration the influences of small scale and the parabolic variation of the transverse shear strains across the thickness of the nanoscale plate and thus, it avoids the employ use of shear correction factors. Also, in this present theory, the effect of transverse shear deformation is included in the axial displacements by using the shear forces instead of rotational displacements as in available high order plate theories. The material properties are supposed to be graded only in the thickness direction and the effective properties for the FG nanoscale plate are calculated by considering Mori-Tanaka homogenization scheme. The equations of motion are obtained using the nonlocal differential constitutive expressions of Eringen in conjunction with the zeroth-order shear deformation theory via Hamilton's principle. Numerical results for vibration of FG nanoscale plates resting on elastic foundations are presented and compared with the existing solutions. The influences of small scale, shear deformation, gradient index, Winkler modulus parameter and Pasternak shear modulus parameter on the vibration responses of the FG nanoscale plates are investigated.

• 한국작물학회지
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• 제55권2호
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• pp.105-110
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• 2010

도복과 관련된 주요 형질인 초장, 3절간장, 좌절중 등에 대한 QTL을 분석을 수행하였으며 도복과 벼멸구 저항성과의 연관 관계에 대한 QTL 및 유의성을 분석하였다. 1. 초장, 3절간장, 모멘트, 도복지수, 좌절중과 같은 도복관련 형질에 대한 QTL을 분석하여 총 13개의 유의성 있는 QTL이 6개의 염색체상에서 확인되었다. 2. 벼멸구 저항성과 주요 농업형질관련 QTL과의 연관관계를 분석한 바, 7번과 8번 염색체 상의 qBPR7, qBPR8은 각각 모멘트(qMo7)와 도복(q3rdin8) 관련 QTL에 연관되어 있었다. 3. Mapping 집단을 저항성 계통군과 감수성 계통군으로 나누어 8개 형질에 대한 차이를 조사한 바, 3절간장과 도복 지수에서 두 집단간에 유의성이 인정되었다. 4. 저항성을 가지는 계통은 간장 및 3절간장 등이 ‘삼강’의 영향으로 ‘낙동’에 비하여 짧은 경향이었으며 이는 신장과 관련된 도복성향에 있어 본 집단에서는 벼멸구 저항성이 강하게 연관이 되었다는 분석결과를 찾을 수 없었다.

• 한국지능시스템학회논문지
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• 제19권5호
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• pp.689-694
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• 2009

본 논문은 일별 및 주별로 시계열 주가를 예측할 수 있는 퍼지 모델을 구성하는 방법을 제안한다. 전통적인 시계열 분석으로 주가를 예측하는 것은 어렵지만 퍼지 모델은 비선형적인 주가 데이터의 특성을 잘 기술할 수 있는 장점을 갖고 있다. 주가 예측 모델에 사용될 입력 정보를 결정하는 데는 상당한 수고가 필요한데, 본 논문에서는 전통적인 캔들 스틱 차트의 정보를 입력변수로 고려한다. 주가 예측 퍼지 모델은 사다리꼴 멤버쉽함수를 갖는 전건부와 비선형식인 후건부로 된 퍼지 규칙으로 구성된다. 차분 진화를 통해 퍼지 모델은 최적화된다. 일별 및 주별로 코스피 지수의 시가, 고가, 저가 및 종가를 예측하는 모델을 만들고 그 성능을 평가한다.

• 한국농공학회논문집
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• 제61권6호
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• pp.123-132
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• 2019

This study is to estimate the spatial soil moisture using Terra MODIS (Moderate Resolution Imaging Spectroradiometer) satellite data and machine learning technique. Using the 3 years (2015~2017) data of MODIS 16 days composite NDVI (Normalized Difference Vegetation Index) and daily Land Surface Temperature (LST), ground measured precipitation and sunshine hour of KMA (Korea Meteorological Administration), the RDA (Rural Development Administration) 10 cm~30 cm average TDR (Time Domain Reflectometry) measured soil moisture at 78 locations was tested. For daily analysis, the missing values of MODIS LST by clouds were interpolated by conditional merging method using KMA surface temperature observation data, and the 16 days NDVI was linearly interpolated to 1 day interval. By applying the RNN-LSTM (Recurrent Neural Network-Long Short Term Memory) artificial neural network model, 70% of the total period was trained and the rest 30% period was verified. The results showed that the coefficient of determination ($R^2$), Root Mean Square Error (RMSE), and Nash-Sutcliffe Efficiency were 0.78, 2.76%, and 0.75 respectively. In average, the clay soil moisture was estimated well comparing with the other soil types of silt, loam, and sand. This is because the clay has the intrinsic physical property for having narrow range of soil moisture variation between field capacity and wilting point.

• Steel and Composite Structures
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• 제25권2호
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• pp.157-175
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• 2017

The novelty of this work is the use of a new displacement field that includes undetermined integral terms for analyzing thermal buckling response of functionally graded (FG) sandwich plates. The proposed kinematic uses only four variables, which is even less than the first shear deformation theory (FSDT) and the conventional higher shear deformation theories (HSDTs). The theory considers a trigonometric variation of transverse shear stress and verifies the traction free boundary conditions without employing the shear correction factors. Material properties of the sandwich plate faces are considered to be graded in the thickness direction according to a simple power-law variation in terms of the volume fractions of the constituents. The core layer is still homogeneous and made of an isotropic material. The thermal loads are assumed as uniform, linear and non-linear temperature rises within the thickness direction. An energy based variational principle is employed to derive the governing equations as an eigenvalue problem. The validation of the present work is checked by comparing the obtained results the available ones in the literature. The influences of aspect and thickness ratios, material index, loading type, and sandwich plate type on the critical buckling are all discussed.

• Smart Structures and Systems
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• 제19권1호
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• pp.21-31
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• 2017

To control the stochastic vibration of a vibration-sensitive instrument supported on a beam, the beam is designed as a sandwich structure with magneto-rheological visco-elastomer (MRVE) core. The MRVE has dynamic properties such as stiffness and damping adjustable by applied magnetic fields. To achieve better vibration control effectiveness, the optimal bounded parametric control for the MRVE sandwich beam with supported mass under stochastic and deterministic support motion excitations is proposed, and the stochastic and shock vibration suppression capability of the optimally controlled beam with multi-mode coupling is studied. The dynamic behavior of MRVE core is described by the visco-elastic Kelvin-Voigt model with a controllable parameter dependent on applied magnetic fields, and the parameter is considered as an active bounded control. The partial differential equations for horizontal and vertical coupling motions of the sandwich beam are obtained and converted into the multi-mode coupling vibration equations with the bounded nonlinear parametric control according to the Galerkin method. The vibration equations and corresponding performance index construct the optimal bounded parametric control problem. Then the dynamical programming equation for the control problem is derived based on the dynamical programming principle. The optimal bounded parametric control law is obtained by solving the programming equation with the bounded control constraint. The controlled vibration responses of the MRVE sandwich beam under stochastic and shock excitations are obtained by substituting the optimal bounded control into the vibration equations and solving them. The further remarkable vibration suppression capability of the optimal bounded control compared with the passive control and the influence of the control parameters on the stochastic vibration suppression effectiveness are illustrated with numerical results. The proposed optimal bounded parametric control strategy is applicable to smart visco-elastic composite structures under deterministic and stochastic excitations for improving vibration control effectiveness.