• 한국농공학회지
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• 제38권2호
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• pp.75-86
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• 1996

The formulas for estimating the constants of storage function model including K and TL for runoff analysis and a distributed storage function model are discussed in this study. First, the relations between parameters of the storage function model and the kinematic runoff model are theoretically examined, and then optimum constants of storage function model are obtained by the Standardized Davidson-Fletcher-Powell (SDFP) method. Through this analysis, theoretical formulas were obtained as $K = 0.63 {\alpha} KsB{^0.6}$ and $T_{L}=0.11 {\alpha} KsB{^0.6} r{^0.4} {_e}$, which are difficult to use practically because of the unclarified definition of shape factors. From a practical point of view, empirical formula were derived as $K=15.6{^0.3} {_m}$ and $T_{L}=2.1B{^0.36} {_m} {_e}/r{^0.4} {_e}$ for applied watersheds. The proposed formulas are verified for several recoded floods at a few points of watersheds. It is also found that the distributed storage function. can be applied to flood runoff analysis using the new formulas aboved mentioned.

• Ecology and Resilient Infrastructure
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• 제10권3호
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• pp.51-63
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• 2023

하천내 수목관리는 홍수와 생태 관리의 균형점을 찾는다는 점에서 매우 중요하며 이를 위해서는 수목이 하천 수위에 미치는 영향을 정확하게 평가할 필요가 있다. 본 연구에서 수목에 작용하는 항력을 고려하는 수목조도공식 8개에 대해 검토하여 실무 수리계산의 관점에서 수목 조도계수 공식의 특성과 적용성을 평가하였다. 개별 수목 조도계수 공식의 수심별 조도계수 산정 특성을 비교하고, 수관부 영향, 수목밀도와 직경 영향, 수목 강성계수 영향, 수위 산정 결과 등을 분석하였다. 동일 조건 수심별 조도계수 비교를 통해 Kouwen and Fathi-Moghadam 공식과 Fischenich 공식은 타 공식에 비해 과도한 조도계수를 산정하였다. 수관부, 수목 직경, 수목 밀도 등은 공식에 따라 상이한 경향을 나타내나 과도한 특이점은 없는 것으로 나타났다. 수목 강성계수를 고려하는 Freeman et al. 공식과 Whittaker et al. 공식은 강성계수에 따라 조도계수가 매우 큰 차이를 나타낸다. 8개 공식의 조도계수 산정 결과를 이용하여 국내 중소규모 가상 하천에 적용한 결과 최대 약 0.2 - 0.4 m 정도의 수위 상승효과를 나타내고 있다. 이상의 검토를 통해 유사한 특성을 가지며 입력자료의 불확실성이 낮은 Baptist et al., Huthoff et al., Cheng, Luhar and Nepf 등의 4개 공식이 실무 적용에 적합한 것으로 판단하였다.

• Journal of applied mathematics & informatics
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• 제28권3_4호
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• pp.913-921
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• 2010

The derivative influence measure is adapted to the Cholesky decomposition of a covariance matrix. Formulas for the derivative influence of observations on the Cholesky root and the inverse Cholesky root of a sample covariance matrix are derived. It is easy to implement this influence diagnostic method for practical use. A numerical example is given for illustration.

• Journal of Communications and Networks
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• 제12권6호
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• pp.582-591
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• 2010

Probabilistic modeling and analysis of correlation metrics have been receiving considerable interest for a long period of time because they can be used to evaluate the performance of communication receivers, including satellite broadcasting receivers. Although differential correlators have a simple structure and practical importance over channels with severe frequency offsets, closedform expressions for the output distribution of differential correlators do not exist. In this paper, we present detection error probability expressions for frame synchronization using differential correlation, and demonstrate their accuracy over channel parameters of practical interest. The derived formulas are presented in terms of the Marcum Q-function, and do not involve numerical integration, unlike the formulas derived in some previous studies. We first determine the distributions and error probabilities for single-span differential correlation metric, and then extend the result to multispan differential correlation metric with certain approximations. The results can be used for the performance analysis of various detection strategies that utilize the differential correlation structure.

• 한국의사학회지
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• 제34권2호
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• pp.65-77
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• 2021

Lee Jema said in his book, Dongui Susebowon, that the prescriptions for Soum constitutional type were already developed by doctors during the Song Jin Yuan China around 10th-13th century. Those prescriptions were common techniques that were used throughout the East Asian region. Among them, Lee Jema specially selected some candidate formulas and modified them according to his constitutional theory. This study investigated how similar his modified prescriptions to original formulas through database[ancient formula database] analysis. 24 out of 24 Soum prescriptions selected meaningful ingredient herbs from the original formula. A 50% or higher concordance rate compared to the original formulas. There are only 9 treatment prescriptions that cannot be checked in the ancient formula database. A future task will be to reveal the practical meanings of the ingredients Lee Jema adjusted for the Soum constitutional type patients.

• Steel and Composite Structures
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• 제32권3호
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• pp.347-359
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• 2019

Modular construction has been increasingly used for mid-to-high rise buildings attributable to the high construction speed, improved quality and low environmental pollution. The individual and repetitive room-sized module unit is usually fully finished in the factory and installed on-site to constitute an integrated construction. However, there is a lack of design guidance on modular structures. This paper mainly focuses on the evaluation of the initial stiffness of corrugated steel plate shears walls (CSPSWs) in container-like modular construction. A finite element model was firstly developed and verified against the existing cyclic tests. The theoretical formulas predicting the initial stiffness of CSPSWs were then derived. The accuracy of the theoretical formulas was verified by the related numerical and test results. Furthermore, parametric analysis was conducted and the influence of the geometrical parameters on the initial stiffness of CSPSWs was discussed and evaluated in detail. The present study provides practical design formulas and recommendations for CSPSWs in modular construction, which are useful to broaden the application of modular construction in high-rise buildings and seismic area.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제25권4호
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• pp.224-261
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• 2021

The interest in implicit-explicit (IMEX) integration methods has emerged as an alternative for dealing in a computationally cost-effective way with stiff ordinary differential equations arising from practical modeling problems. In this paper, we introduce implicit-explicit second derivative linear multi-step methods (IMEX SDLMM) with error control. The proposed IMEX SDLMM is based on second derivative backward differentiation formulas (SDBDF) and recursive SDBDF. The IMEX second derivative schemes are constructed with order p ranging from p = 1 to 8. The methods are numerically validated on well-known stiff equations.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.65-68
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• 1997

Vickers hardness is defined as indenting force per unit area indented by a pyramid-shaped diamond at the hardness test. It is well known that Vickers hardness has a direct relation with the flow stress of the strain-hardened material. This relation was theoretically investigated and the result was summerized in a form of algebraic equation in the last paper. In the present paper and experimental validation of this theoretical relation is given along with mathematical formulas for conversion of Vickers hardness into the flow stress in the strain-hardened material for practical use.

• 한국해양공학회지
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• 제5권1호
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• pp.64-70
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• 1991

The design theory of roller gate has been systematized laying more emphasis on practical formulas than theoretical ones and the design procedure of the existing gate facilites is reviewed and analyaed on economical viewpoint and safety factor. The design theory of timoshenko, the thechnical standards for hydraulic gate and penstock of Japan, and the design standards for waterworks structures of Germany are applied to the study of optimal design of a gate leaf. In this study, gate leaf which is now being operated for water control at the seadike, estuary dam and reservoir dam are adopted as a mode, and a new design method by the computer is proposed through the variation of design elements within practical ranges. As a result, safety factor and economical design can be made by using T-beams to the horizontal and vertical beam of the gate leaf instead of H-beams used in the existing seadike roller gate at Asan, and total weight of gate leaf is reduced by the present optimization.

• 대한토목학회논문집
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• 제10권4호
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• pp.25-33
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• 1990

모멘트 분배법(分配法)은 지난 60년(年) 동안 연속(連續)보와 라멘 등의 부정정구조물(不靜定構造物)의 근사해법(近似解法)으로 널리 사용되어 왔다. 이 방법(方法)은 구조부재(構造部材)의 양단(兩端)모멘트를 반복적(反復的)인 수계산(手計算)으로 산정(算定)하는 것이다. 본(本) 연구(硏究)는 모메트 분배법(分配法)을 이용하여 수렴형공식(收斂型公式)을 전개(展開)한 것이다. 이들 공식(公式)은 재래식(在來式) 모멘트 분배법(分配法)의 단점(短點)이라고 할 수 있는 결과(結果)의 근사성(近似性) 및 과정(過程)의 복잡성(複雜性)을 극복(克服)함으로써 간단(簡單)하고도 정확(正確)한 해(解)를 제공(提供)한다. 여기 제안(提案)된 공식(公式)들은 부정정(不靜定) 뼈대의 새로운 해법(解法)의 하나가 될 것이며, 특히 연속(連續)보의 영향선(影響線)의 작도(作圖)에 효과적(效果的)으로 기여(寄與)함으로써 구조설계(構造設計)의 실무(實務)에 큰 도움이 될 것이다.