• Structural Engineering and Mechanics
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• 제89권1호
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• pp.1-11
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• 2024

This article introduces a novel analytical model for examining the impact of porosity on shear correction factors (SCFs) in functionally graded porous beams (FGPB). The study employs uneven and logarithmic-uneven modified porosity-dependent power-law functions, which are distributed throughout the thickness of the FGP beams. Additionally, a modified exponential-power law function is used to estimate the effective mechanical properties of functionally graded porous beams. The correction factor plays a crucial role in this analysis as it appears as a coefficient in the expression for the transverse shear stress resultant. It compensatesfor the assumption that the shear strain is uniform across the depth of the cross-section. By applying the energy equivalence principle, a general expression for static SCFs in FGPBs is derived. The resulting expression aligns with the findings obtained from Reissner's analysis, particularly when transitioning from the two-dimensional case (plate) to the one-dimensional case (beam). The article presents a convenient algebraic form of the solution and provides new case studies to demonstrate the practicality of the proposed formulation. Numerical results are also presented to illustrate the influence of porosity distribution on SCFs for different types of FGPBs. Furthermore, the article validates the numerical consistency of the mechanical property changesin FG beams without porosity and the SCF by comparing them with available results.

• 수산해양기술연구
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• 제35권3호
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• pp.335-342
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• 1999

The purpose of present research is to develop and efficient numerical method for the calculation of potential flow and predict the wave-making resistance for the application to ship design of tuna purse seiner. Havelock was considered the wave resistance of a post extending vertically downwards through the water from the surface, its section by a horizontal plane being the same at all depths and having its breadth small compared with its length. This enables us to elucidate certain points of interest in ship resistance. However, the ship has not infinite draft. So, the problem which is investigated ind detail in this paper is the wave resistance of a mathematical quadratic model in a uniform stream. The paper deals with the numerical calculation of potential flow around the series 60 with forward velocity by the new slender ship theory. This new slender ship theory is based on the asymptotic expression of the Kelvin-source, distributed over the small matrix at each transverse section so as to satisfy the approximate hull boundary condition due to the assumption of slender body. The numerical results using the panel shift method and finite difference method are compared with the experimental results for wigley mono hull. There are no differences in the wave resistance. However, it costs much time to compute not only wave resistance but also wave pattern over some range of Froude numbers. More improvements are strongly desired in the numerical procedure.

• 한국작물학회지
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• 제60권1호
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• pp.33-40
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• 2015

재배환경에 따른 단백질 발현을 이차원전기영동을 이용하여 단백질 발현양상을 확인하고 이미지 분석을 통하여 단백질 발현 정도를 수치화하여 비교 분석한 결과, 재배환경에 따른 단백질 발현 양상은 전반적으로 매우 유사하였으며, 주요 단백질의 발현에는 차이가 없었다. 하지만 논과 밭, 즉 재배환경은 단백질의 발현 정도에는 영향을 미치는 것을 확인 할 수 있었다. 공시품종들 중에서 백천콩은 다른 세 품종과는 다르게 논에서 단백질 발현 정도가 밭에서의 단백질 발현 정도보다 높았다. 이 결과로 보아 품종마다 재배환경에 따른 단백질의 발현 정도에 차이가 있는 것으로 사료된다. 향후, 단백질 총 함량을 재배환경에 따라 비교하고 또한 질량분석을 통하여 증가 또는 감소되는 단백질의 기능을 확일 할 필요가 있다고 사료된다.

• 한국실내디자인학회논문집
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• 제16호
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• pp.175-181
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• 1998

The purpose of this study was to analyze the characteristics of expression and formal principle of universalism in Architectural Composition. Theorical category is to find universal system with the connection between idea of society and tradition in compositional frame the results were as follows : First it is the pursuit of divine. Through Middle Age and Renaissance universalism of principles in Architectural Composition is appeared a numerical order and human proportion with applying of cosmology. Second it is the pursuit of schema. With the simplicity of formal image it represented to the geometrical form for its clearness. Third it is the pursuit of typology. As to play a role of decisive factor in formal construction type represented the model with abstraction of shape.

• Journal of electromagnetic engineering and science
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• 제9권3호
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• pp.111-117
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• 2009

This paper presents an energy-efficient and bandwidth-efficient 2-1-1 relaying scheme in which a sensor node(SN) assists two others in their data transmission to a clusterhead in WSNs(Wireless Sensor Networks) using LEACH (Low-Energy Adaptive Clustering Hierarchy). We derive the closed-form BER expression of this scheme which is also a general BER one for the decode-and-forward cooperative protocol and prove that the proposed scheme performs the same as the conventional relaying scheme but obtains higher channel utilization efficiency. A variety of numerical results reveal the relaying can save the network energy up to 11 dB over single-hop transmission at BER of $10^{-3}$.

• 응용통계연구
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• 제24권6호
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• pp.1103-1113
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• 2011

Gene expression data is obtained through many stages of an experiment and errors produced during the process may cause missing values. Due to the distinctness of the data so called 'small n large p', genes have to be selected for statistical analysis, like classification analysis. For this reason, imputation and gene selection are important in a microarray data analysis. In the literature, imputation, gene selection and classification analysis have been studied respectively. However, imputation, gene selection and classification analysis are sequential processing. For this aspect, we compare the performance of classification methods after imputation and gene selection methods are applied to microarray data. Numerical simulations are carried out to evaluate the classification methods that use various combinations of the imputation and gene selection methods.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
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• pp.742-745
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• 2004

Most of options pricing theory including Black and Scholes continuous model and Cox, Ross, and Rubinstein(CRR)'s binomial lattice model were developed based on the notion that continually revised risk-free hedges involving options and stock should earn the risk-free interest rate. This notion is valid with the assumption that the investor's attitude toward risk is neutral. In reality, this assumption may be frequently violated. Therefore, Hodder, Mello, and Sick proposed the way to value real options using the risk-adjusted interest rate. However, they did not show how to derive the mathematical expression for it. In this paper, we will clearly present how to obtain the mathematical expression for the risk-adjusted interest rate for real options and demonstrate two numerical examples to show its applicability.

• Journal of Power Electronics
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• 제18권4호
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• pp.1165-1177
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• 2018

This paper investigates the active damping of grid-connected LCL filter resonance using high-pass filter (HPF) of the grid current. An expression for such HPF is derived in terms of the filter components. This expression facilitates a general study of the actively damped filter behavior in the discrete time domain. Limits for the HPF parameters are derived to avoid the excitation of unstable open loop poles since such excitation can reduce both the damping performance and the system robustness. Based on this study, straightforward co-design steps for the active damping loop along with the fundamental current regulator are proposed. A numerical example along with simulation and experimental results are presented to verify the theoretical analyses.

• International journal of advanced smart convergence
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• 제9권3호
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• pp.49-58
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• 2020

Non-orthogonal multiple access (NOMA) has been recognized as a significant technology in the fifth generation (5G) and beyond mobile communication, which encompasses the advanced smart convergence of the artificial intelligence (AI) and the internet of things (IoT). In NOMA, since the channel resources are shared by many users, it is essential to establish the user fairness. Such fairness is achieved by the power allocation among the users, and in turn, the less power is allocated to the stronger channel users. Especially, the first and second strong channel users have to share the extremely small amount of power. In this paper, we consider the power optimization for the two users with the small power. First, the closed-form expression for the power allocation is derived and then the results are validated by the numerical results. Furthermore, with the derived analytical expression, for the various channel environments, the optimal power allocation is investigated and the impact of the channel gain difference on the power allocation is analyzed.

• Structural Engineering and Mechanics
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• 제4권4호
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• pp.383-396
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• 1996

In this paper, the behavior of plates partially restrained against rotation under stress gradient is investigated. As a first stage, an energy formulation is presented to model this boundary condition and a general expression is derived for the prediction of the elastic buckling of the plate under this general loading condition. The accuracy of the derived expression is compared numerically using the Galerkin method with other available data for the two limiting conditions of rotationally free and clamped boundaries. Results show that the prediction is within a 5% difference. The influence of rotational restraint and stress gradient upon the buckling load and the associated buckling mode is investigated. Numerical results show sensitivity of the buckling mode to the degree of rotational restraint and the variation of the buckling load with the stress gradient.