• Structural Engineering and Mechanics
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• 제20권3호
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• pp.363-380
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• 2005

The cable tension plays an important role in the construction, assessment and long-term health monitoring of cable structures. The cable vibration equation is nonlinear if cable sag and bending stiffness are included. The engineering implementation of a vibration-based cable tension evaluation is mostly carried out by the simple taut string theory. However, the simple theory may cause unacceptable errors in many applications since the cable sag and bending stiffness are ignored. From the practical point of view, it is necessary to have empirical formulas if they are simple and yet accurate. Based on the solutions by means of energy method and fitting the exact solutions of cable vibration equations where the cable sag and bending stiffness are respectively taken into account, the empirical formulas are proposed in the paper to estimate cable tension based on the cable fundamental frequency only. The applicability of the proposed formulas is verified by comparing the results with those reported in the literatures and with the experimental results carried out on the stay cables in the laboratory. The proposed formulas are straightforward and they are convenient for practical engineers to fast estimate the cable tension by the cable fundamental frequency.

• Structural Engineering and Mechanics
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• 제49권1호
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• pp.129-145
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• 2014

In order to investigate the characteristics of torsional wind loads on rectangular tall buildings, five models with different rectangular cross-sections were tested in a boundary wind tunnel. Based on the test results, the RMS force coefficients, power spectrum densities as well as vertical correlation functions of torsional wind loads were analyzed. Formulas that took the side ratio as parameters were proposed to fit the test results above. Comparisons between the results calculated by the formulas and the wind tunnel measurements were made to verify the reliability of the proposed formulas. An simplified expression to evaluate the dynamic torsional wind loads on rectangular tall buildings in urban terrain is presented on basis of the above formulas and has been proved by a practical project. The simplified expressions as well as the proposed formulas can be applied to estimate wind-induce torsional response on rectangular tall buildings in the frequency domain.

• 대한한의학방제학회지
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• 제18권2호
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• pp.109-124
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• 2010

In this study, we considered the usecase of formulas containing either Fritillaria Bulb (川貝母) or Fritillaria Thunbergii Bulb (浙貝母). These two medicinal materials are distinguished in the Korea Pharmacopoeia and circulating the market separately. But only term "貝母" is traditionally written for describing formulas, and the proper material will have to be determined by a subjective point of view. So, we have comparatively studied the nature, flavor, meridian entry, effect and indication of two materials first. Then we have chosen 54 formulas that "貝母" was used as a primary material from the Donguibogam and the Bangyachappyun, and we have compared effects, indications of two materials and indication of 54 formulas. Finally, we have suggested proper materials for each formula by referring the results above and sentences, which is explaining formulas and the roles of materials in the combination for treatment. The analysis showed that Fritillaria Bulb is proper to 15 formulas, Fritillaria Thunbergii Bulb is proper to 31 ones. This number is 85.2% of 54 formulas and this result shows that we need to distinguish between two materials for "貝母" in the formulas from old traditional literature. For the rest 8 formulas (14.8%), we could not analyze which material is proper or not.

• 콘크리트학회논문집
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• 제18권1호
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• pp.3-12
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• 2006

화해를 입은 콘크리트 구조물의 거동은 많은 변수에 따라 영향을 받는 복잡한 현상을 나타낸다. 연구에서 고려되는 변수들은 콘크리트 및 철근이 받는 온도크기 및 가열시간, 콘크리트와 철근의 기계적 물성, 함수율, 피복두께, 편심유무, 기둥단면형상 등을 들 수 있다. 이러한 주요변수들이 화해를 입은 기둥의 잔존내력에 미치는 영향을 추적할 수 있는 수치해석 모델이 존재하나 실무에서 용이하게, 그러나 어느 정도 정확성을 갖고 화해 입은 기둥의 잔존내력을 예측할 수 있는 실용예측식이 필요하다. 본 연구에서는 이 목적을 위하여 화해를 입은 보통강도 철근콘크리트 정방형 기둥에 대하여 수치해석적 모델에 의한 잔존내력 예측치를 근사적으로 산정할 수 있는 실용예측식을 개발하였다. 개발된 식은 화해시간, 콘크리트강도, 철근비, 기둥단면크기의 영향을 고려한다. 개발된 실용예측식에 의한 잔존내력값은 수치해석 모델에 의한 잔존내력값을 비교적 근접하게 예측하였다. 화해를 입은 보통강도 철근콘크리트 기둥에 대한 잔존내력, 안정성 및 추가 필요내력의 산정 등에 대한 예제를 수록하였다.

• Transactions on Electrical and Electronic Materials
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• 제4권6호
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• pp.21-27
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• 2003

Methods of calculation of polarizers and splitters for visible spectra based on a multi-layer dielectric system are considered. Practical formulas for calculation are given. For example the cases of a splitter calculation when R$\_$s/ > 70% and R$\_$p/$\leq$ 30% or R$\_$s/=R$\_$p/ were considered. The formulas of the effective layers method are of practical use. The optical characteristics of calculated and fabricated polarizers and splitters for 650nm and 780nm wavelengths are presented.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.817-832
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• 2021

In this paper, a simple practical method to estimate the drag of Super-Cavitating Underwater Vehicles (SCUV) is proposed that can obtain the drag with only principal dimensions in an initial design stage. SCUV is divided into cavitator, forebody, afterbody, base, and control fin and the drag of each part is estimated. The formulas for the drag coefficient are proposed for the disk and cone type cavitators and wedges used as control fins. The formulas are a function of cavitation number, cone or wedge angle, and Reynolds number. This method can confirm the drag characteristics of SCUV that the drag hump appears according to the coverage of the body by the cavity and the cavitator drag remains only when the entire body is covered by cavity. Applying this method to SCUV of various shapes, it is confirmed that the effects of cavitating and non-cavitating conditions, cavitator and body shape, and speed could be found.

• Steel and Composite Structures
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• 제5권1호
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• pp.71-86
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• 2005

Based on the test data of Nippon Steel Corporation, the formulas for calculating mechanical properties of fire-resistant (FR) steel at elevated temperatures have been established. A practical approach for fire safety design of FR steel members, including axially compressed members, flexural members and eccentrically compressed members, is developed in this paper. Compared with the full-scale specimen experiments and FEM numerical analysis, this practical approach for fire safety design of FR steel members is demonstrated to be effective and precise.

• Korean Journal of Acupuncture
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• 제27권3호
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• pp.79-95
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• 2010

Objective : In this study, we try to identify the herbal formulated by Heo Im from Kyeongheombang(經驗方), and investigate its medical property. Method : Those articles referenced from Heo Im's herbal formulas in "Sauikyeongheombang(四醫經驗方)" were extracted and results were quantitatively analyzed. From extracted empirical formulas, those categorized as externally applicable formulas were grouped by several standards and their medical significance was analyzed. Results and Conclusions : 85 and 66 articles were designated to be referred from Heo(許) in "Sauikyeongheombang" and "Uibanghapbu(醫方合部)" in each category, and 263 and 155 were identified to be Heo Im formulas, respectively. Externally applicable formulas in Heo Im's empirical recipes have following characteristics. First, various methods were used by Heo Im. Second, Heo Im's empirical formulas suggest useful clinical information maximizing therapeutic effect, which is of much value, originated from his practical experiences as a clinician. Third, Heo Im's therapy favorably succeeds the tradition of Hyangyak-medicine and Empirical -medicine. From this information, Heo Im is thought to have had rich insight and experience, not only in acupuncture but also in the prescription of herbal formulas at those days.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.370-377
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• 2002

Hwang et al (2001) proposed a new method for an evaluation of equivalent damping ratios of a linear structure with linear or nonlinear damping devices. This procedure has a disadvantage that it requires time history analysis for the whole system including damping devices, which may be troublesome for practical application. To tackle this problem closed form formulas for equivalent damping ratios are proposed in this study. It is assumed that the responses of MDOF system can be reproduced by an equivalent SDOF system which vibrates in a fundamental mode. The numerical analyses of a ten-story building equipped with linear viscous damper or active mass damper or friction damper show the effectiveness of equivalent SDOF model and closed form formulas.

• 한국항해학회지
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• 제24권3호
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• pp.123-132
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• 2000

In order to improve the ship maneuverability, It is important to estimate precisely the hydrodynamic coefficients of added mass forces acting on a ship especially in shallow waters, and simple methods for predicting such hydrodynamic forces Is also very desirable. In the previous paper using 3-Dimension potential flow theory, it has been demonstrated that potential calculation is available to estimate added mass coefficients. The present work is aimed at the suggestion of the simplified formulas for predicting the translation and lateral motion of added mass coefficients in shallow water. So, 3-D potential flow theory is also used to calculate the added mass coefficients in deep and shallow waters for Series 60 model which has 5 different kinds of block coefficients (0.6-0.8), SR196 model and T/S HANNARA. After some series computation, simplified formulas for Predicting the added mass force in shallow waters is suggested based on the computation results of Series 60 model. The formulas consist of the combination of principal dimensions and the water depth; d/B, Cb, d/H. The predicted results are compared with the Computation results for SR196 model and T/S HANNARA. The precision of predicted results by simplified formulas are good enough for the practical use. (d/B : draft-Breadth ratio, d/H draft-Water depth ratio, Cb : Block coefficients).