• Computers and Concrete
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• 제19권6호
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• pp.725-736
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• 2017

This paper presents the two-, three-, and four-lane transverse reduction factor based on FEA method, probability theory, and the recently actual traffic flow data. A total of 72 composite girder bridges with various spans, number of lanes, loading mode, and bridge type are analyzed with time-varying static load FEA method by ANSYS, and the probability models of vehicle load effects at arbitrary-time point are developed. Based on these probability models, in accordance to the principle of the same exceeding probability, the multi-lane transverse reduction factor of these composite girder bridges and the relationship between the multi-lane transverse reduction factor and the span of bridge are determined. Finally, the multi-lane transverse reduction factor obtained is compared with those from AASHTO LRFD, BS5400, JTG D60 or Eurocode. The results show that the vehicle load effect at arbitrary-time point follows lognormal distribution. The two-, three-, and four-lane transverse reduction factors calculated by using FEA method and probability respectively range between 0.781 and 1.027, 0.616 and 0.795, 0.468 and 0.645. Furthermore, a correlation between the FEA and AASHTO LRFD, BS5400, JTG D60 or Eurocode transverse reduction factors is made for composite girder bridges. For the two-, three-, and four-lane bridge cases, the Eurocode code underestimated the FEA transverse reduction factors by 27%, 25% and 13%, respectively. This underestimation is more pronounced in short-span bridges. The AASHTO LRFD, BS5400 and JTG D60 codes overestimated the FEA transverse reduction factors. The FEA results highlight the importance of considering span length in determining the multi-lane transverse reduction factors when designing two-lane or more composite girder bridges. This paper will assist bridge engineers in quantifying the adjustment factors used in analyzing and designing multi-lane composite girder bridges.

• Structural Engineering and Mechanics
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• 제42권5호
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• pp.715-728
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• 2012

This paper deals with determining the fundamental frequency of tall buildings that consist of framed tube, shear core, belt truss and outrigger systems in which the framed tube and shear core vary in size along the height of the structure. The effect of belt truss and outrigger system is modeled as a concentrated rotational linear spring at the belt truss and outrigger system location. Many cantilevered tall structures can be treated as cantilevered beams with variable cross-section in free vibration analysis. In this paper, the continuous approach, in which a tall building is replaced by an idealized cantilever continuum representing the structural characteristics, is employed and by using energy method and Hamilton's variational principle, the governing equation for free vibration of tall building with variable distributed mass and stiffness is obtained. The general solution of governing equation is obtained by making appropriate selection for mass and stiffness distribution functions. By applying the separation of variables method for time and space, the governing partial differential equation of motion is reduced to an ordinary differential equation with variable coefficients with the assumption that the transverse displacement is harmonic. A power-series solution representing the mode shape function of tall building is used. Applying boundary conditions yields the boundary value problem; the frequency equation is established and solved through a numerical process to determine the natural frequencies. Computer program has been developed in Matlab (R2009b, Version 7.9.0.529, Mathworks Inc., California, USA). A numerical example has been solved to demonstrate the reliability of this method. The results of the proposed mathematical model give a good understanding of the structure's dynamic characteristics; it is easy to use, yet reasonably accurate and suitable for quick evaluations during the preliminary design stages.

• 한국의사학회지
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• 제34권2호
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• pp.89-96
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• 2021

This research aims to find a way to utilize the literature to select the herbs to be added or subtracted according to the condition of the patient after determining the basic prescription to be used for the patient. The study is based on data concerning the herbal composition and application of prescriptions described in the Donguibogam. The composition herbs was expressed as a weight ratio, the standard deviation of the weight ratio was calculated for each prescription, and the case where the weight ratio was greater than the base value (highest weight ratio - standard deviation) was designated as a principal herb. The various expressions of applications were changed to representative terms by the researcher and used to calculate the frequency. Of the 4,373 prescriptions for Donguibogam, 3,307 were able to be expressed in terms of weight ratios with 640 prescriptions using Rehmannia glutinosa, Cnidium officinale, Angelica gigas and Paeonia lactiflora as the principle herb. Of the 640 prescriptions, 508 prescriptions included applied information. Rehmannia glutinosa can also be used for symptoms such as fetal leakage(胎漏), short ingestion(食少), fever(發熱), dazed expression(眼花). Cnidium officinale can also be used for symptoms such as migraine(偏頭痛), stroke(中風癱瘓), tetanus(破傷風). Angelica gigas can also be used for symptoms such as forgetfulness(健忘), incontinence of urination(小便不通), palpitations(驚悸). Paeonia lactiflora can also be used for symptoms such as heart pain and abdominal pain(心腹痛), cough(咳嗽).

• Structural Engineering and Mechanics
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• 제86권3호
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• pp.291-309
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• 2023

This paper addresses the finite element modeling of functionally graded porous (FGP) beams for free vibration and buckling behaviour cases. The formulated finite element is based on simple and efficient higher order shear deformation theory. The key feature of this formulation is that it deals with Euler-Bernoulli beam theory with only three unknowns without requiring any shear correction factor. In fact, the presented two-noded beam element has three degrees of freedom per node, and the discrete model guarantees the interelement continuity by using both C⁰ and C¹ continuities for the displacement field and its first derivative shape functions, respectively. The weak form of the governing equations is obtained from the Hamilton principle of FGP beams to generate the elementary stiffness, geometric, and mass matrices. By deploying the isoparametric coordinate system, the derived elementary matrices are computed using the Gauss quadrature rule. To overcome the shear-locking phenomenon, the reduced integration technique is used for the shear strain energy. Furthermore, the effect of porosity distribution patterns on the free vibration and buckling behaviours of porous functionally graded beams in various parameters is investigated. The obtained results extend and improve those predicted previously by alternative existing theories, in which significant parameters such as material distribution, geometrical configuration, boundary conditions, and porosity distributions are considered and discussed in detailed numerical comparisons. Determining the impacts of these parameters on natural frequencies and critical buckling loads play an essential role in the manufacturing process of such materials and their related mechanical modeling in aerospace, nuclear, civil, and other structures.

• 대한토목학회논문집
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• 제5권3호
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• pp.31-38
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• 1985

아치의 미소요소(微小要素)에 작용(作用)하는 합응력(合應力)들의 평형방정식(平衡方程式)과 D'Alembert의 원리(原理)를 이용(利用)하여 회전관성(回轉慣性)을 고려(考慮)한 포물선(抛物線)아치의 자유진동(自由振動)에 대한 미분방정식(微分方程式)을 유도(誘導)하였다. 본(本) 연구(硏究)에서 유도(誘導)한 미분방정식(微分方程式)을 검증(檢證)하기 위하여 포물선(抛物線)아치의 미분방정식(微分方程式)을 보의 미분방정식(微分方程式)으로 수렴(收斂)시킨 결과(結果), 포물선(抛物線)아치의 미분방정식(微分方程式)이 보의 미분방정식(微分方程式)으로 수렴(收斂)되는 것을 보였다. 본(本) 연구(硏究)에서 유도(誘導)한 미분방정식(微分方程式)을 시행착오적(試行錯誤的) 고유치문제(固有値問題)와 Runge-Kutta method를 이용(利用)하여 수치해석(數値解析)하였으며, 본(本) 연구(硏究)의 수치해석(數値解析) 결과(結果)와 SAP IV의 결과(結果)가 잘 일치(一致)함을 보였다.

• 산학경영연구
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• 제17권
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• pp.111-136
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• 2004

양도소득세의 과세대상은 토지 또는 건물의 양도, 부동산에 관한 권리의 양도, 비상장주식의 양도 및 기타자산의 양도로 규정하고 있다. 부동산과 관련된 양도소득과세에서 양도차익의 계산은 양도가 액과 취득가액의 결정이 매우 중요하다. 우리나라에서 양도차익의 결정방법은 기준시가를 적용하는 방법과 실지거래가액을 적용하여 계산하는 방법이 있으나 세법에서는 부동산의 양도에 따른 양도차익의 산정은 원칙적으로 기준시가의 방법을 적용하고 예외적으로 실지거래가액에 의한 방법을 적용하고 있다. 본 연구에서는 기준시가방법과 실지거래가액방법 중 어떠한 방법이 조세이론상으로 적정하며 또한 소득의 재분배기능에 기여하는가를 검토하여 그에 대한 개선방안을 제시하였다. 실지거래가액에 의한 양도차익의 평가방법은 실지로 거래한 금액을 기준으로 양도가액 취득가액으로 확정시키는 것으로 실질과세의 원칙을 비롯한 조세원칙에 타당성이 있다. 기준시가제도를 채택하는 이유는 양도자와 양수자간의 단합으로 세액을 낮게 신고하거나, 관계공무원과 양도자와의 통정으로 세정이 문란해지 등의 여러 가지 이유에서 기준시가를 채택하고 있어나 이는 실질과세의 원칙과 근거과세에 위배되어 조세의 불균형이 이루어지고 있다. 따라서 양도차익결정방법을 기준시가의 원칙에서 실지거래가액으로 개정하여야 실질과세 원칙과 근거과세의 원칙에 합당하다고 할 것이다.

• 대한한의학원전학회지
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• 제33권4호
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• pp.147-165
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• 2020

Objectives : The meaning of the verses '久而增氣' and '氣增而久' from the 『Suwen·Zhizhenyaodalun』 were studied to complement previous annotations. Methods : Based on problems uncovered in previous annotations, the verses "久而增氣, 物化之常也" and "氣增而久, 夭之由也" were examined in detail. Results & Conclusions : Previous annotations on the verse "久而增氣, 物化之常也" have conflicting opinions. Therefore, related contents in the 『Huangdineijing』 were examined to resolve and complement existing interpretations. The meaning of '久' in the phrase "久而增氣, 物化之常也," not only has a temporal meaning but also refers to the Jing process[精化｣. The Jing process is where the Jing Qi is used to produce Jing through a feedback process that results in enlivening materials such as Jing, Qi, and Blood. The phrase "氣增而久, 夭之由也" refers to an early death caused by expansion of rough Qi that has failed to go through the Jing process because of excessive greed and failure to follow the seasonal principle. These phrases from the 『Suwen·Zhizhenyaodalun』 reminds us that the Qi's Jing process is an important factor in determining longevity, shedding new light on themes such as the pattern of food intake, cultivation, longevity, treating before illness, prevention, etc., for today.

• 펄프종이기술
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• 제34권5호
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• pp.39-48
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• 2002

The water retention of coating colors can be accurately measured by devices such as an AA-GWR water retention meter whose principle of measurement Is based on pressure filtration of coatings under an externally applied air pressure over a certain period of time. It was hypothesized that such devices could be also used to determine the immobilization solids (IMS) of coating colors by determining a sudden drop in the rate of dewatering, that is, a sudden change in the drainage curves. To test this hypothesis, the immobilization solids of coating colors containing various thickeners and water retention additives at different levels were first accurately measured by a modified immobilization tester based on the well-known gloss drop method, and then their values were compared with those obtained by an AA-GWR water retention tester. They agreed very well and showed that the standard deviation is only 0.14% in the IMS points between both methods. This good agreement was not surprising because both test methods are based on the same end-point, that is, the immobilization solids point at which menisci begin to form at the coating surface. Theoretical considerations supporting this new method for measuring the immobilization solids of coating colors are presented and some recommendations for the test method are discussed. Also, the effect of various thickeners and water retention additives on the properties and printability of coated papers is discussed.

• 한국지구과학회지
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• 제29권2호
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• pp.117-127
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• 2008

한반도와 그 주변에서 발생한 44개의 지진에 대한 지진원 상수들을 결정하여 그들 사이의 관계를 조사하였다. 모서리 주파수와 지진모멘트의 결정에는 Snoke(1987)의 방법을 적용하였다. 일반적으로 하나의 지진에 대하여 다른 관측소에서 결정된 지진원 상수들은 서로 다른 값을 보여 준다. 이러한 불일치는 지진원에서의 에너지 확산과 전파과정중의 감쇠 및 증폭의 방향별 차이에 대한 불충분한 고려에서 기인하는 것으로 해석된다 이러한 방향에 따른 효과를 제거하기 위하여 모서리 주파수와 지진모멘트는 평균값을 취했으며, 이 평균값으로부터 다른 지진원 상수들을 결정하였다. 이 연구에서 구한 정적인 응력강하량은 일정한 크기 이상의 지진에 대하여 지진모멘트와 무관한 경향을 보여 준다. 지진모멘트가 대략 $1.0{\times}10^{22}$ dyne-cm($M_L = 4.0$에 대응) 이하인 지진은 지진모멘트가 감소함에 따라 응력강하량이 감소하는 경향을 보여준다. 이 사실은 어떤 한계규모 이하의 지진에서 지진원 상수들 사이의 비례법칙이 깨짐을 의미한다.

• Steel and Composite Structures
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• 제51권2호
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• pp.185-202
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• 2024

In this research paper, and for the first time, wave propagations in sigmoidal imperfect functionally graded material plates are investigated using a simplified quasi-three-dimensionally higher shear deformation theory (Quasi-3D HSDTs). By employing an indeterminate integral for the transverse displacement in the shear components, the number of unknowns and governing equations in the current theory is reduced, thereby simplifying its application. Consequently, the present theories exhibit five fewer unknown variables compared to other Quasi-3D theories documented in the literature, eliminating the need for any correction coefficients as seen in the first shear deformation theory. The material properties of the functionally graded plates smoothly vary across the cross-section according to a sigmoid power law. The plates are considered imperfect, indicating a pore distribution throughout their thickness. The distribution of porosities is categorized into two types: even or uneven, with linear (L)-Type, exponential (E)-Type, logarithmic (Log)-Type, and Sinus (S)-Type distributions. The current quasi-3D shear deformation theories are applied to formulate governing equations for determining wave frequencies, and phase velocities are derived using Hamilton's principle. Dispersion relations are assumed as an analytical solution, and they are applied to obtain wave frequencies and phase velocities. A comprehensive parametric study is conducted to elucidate the influences of wavenumber, volume fraction, thickness ratio, and types of porosity distributions on wave propagation and phase velocities of the S-FGM plate. The findings of this investigation hold potential utility for studying and designing techniques for ultrasonic inspection and structural health monitoring.