• 한국농공학회지
• /
• 제42권6호
• /
• pp.72-82
• /
• 2000

Many lot of books introduce the methods to calculate the time of concentration, and these are described as various forms of formulas. There are few formulas appropriate for our basin characteristics Therefone, there are problems to make excessive or less estimation when these formulas are used. To solve these problems, comparison of formulas and sensitivity analysis for them were made with converting parameters. Finally, Time of concentration was estimated to derive Application limits for 3 watersheds by standardized formulas. In the case of input parameters analysis, SCS formula has the highest value by the length, Kerby by the height and SCS by the slope, respectively, while Kraven formula has the lowest value among them. Concerning the relative sensitivity by Taylor series, the time of concentration showed the constant effect while increasing of the length and slope, and the length was more sensitive than the slope in parameters. Finally the standardization formula developed in this study was applied to derive application limits for 3 watersheds(total 17 subbasins). In this case, Rziha(8 subbasins) and SCS(9 subbasins) formulas were the most similar to observed data of total 17 subbasins respectively. Application limits were about 300~500$\textrm{km}^2$ area, 30~60km length and under 0.01 slope for Rziha formula and about 100~200$\textrm{km}^2$ area, 10~30km length, and over 0.01 slope for SCS formula, respectively.

• 한국대기환경학회지
• /
• 제25권6호
• /
• pp.539-549
• /
• 2009

The purpose of this study is to estimate hourly Asian dust emission flux in springtime by using the optimized Weather Research Forecasting model (WRF) in order to accurately predict the horizontal flux of Asian dusts. Asian dust emission flux using 5 empirical formulas such as US EPA, Park and Inn, Wang, The Goddard Chemistry Aerosol Radiation and Transport (GOCART) and Dust Entrainment and Deposition (DEAD) were calculated and compared by using classified land-use types and size distribution at various locations in China and Mongolia together with the hourly meteorological elements of the WRF model. As a result, the empirical formula in US EPA among them, which was considered the various conditions such as vegetation, soil type and terrain, was better than the other 4 empirical formulas. However, these formulas were adjusted hourly and vertically in time and space because there was different order and time resolution of dust emissions from original empirical formulas.

• 대한수학회보
• /
• 제51권4호
• /
• pp.995-1003
• /
• 2014

A remarkably large number of integral formulas involving a variety of special functions have been developed by many authors. Also many integral formulas involving various Bessel functions have been presented. Very recently, Choi and Agarwal derived two generalized integral formulas associated with the Bessel function $J_{\nu}(z)$ of the first kind, which are expressed in terms of the generalized (Wright) hypergeometric functions. In the present sequel to Choi and Agarwal's work, here, in this paper, we establish two new integral formulas involving the generalized Bessel functions, which are also expressed in terms of the generalized (Wright) hypergeometric functions. Some interesting special cases of our two main results are presented. We also point out that the results presented here, being of general character, are easily reducible to yield many diverse new and known integral formulas involving simpler functions.

• 대한전기학회논문지:전력기술부문A
• /
• 제49권1호
• /
• pp.37-42
• /
• 2000

The radio noise produced by corona discharge in high voltage transmission lines is one of the most important line design considerations. Therefore it is necessary for transmission line designers to pre-evaluate radio noise using prediction formulas or field test results. In this paper, more accurate and useful formulas for predicting radio noise during fair and foul weathers in high voltage AC transmission lines were proposed through comparison with the existing formulas. Also it was verified by comparing with the long-term measured data from operating lines that the proposed formulas are more accurate. The proposed prediction formulas are developed by the applications of nonlinear least squares optimization method to radio noise database collected from lines throughout the world.

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

• 대한한의학회지
• /
• 제35권1호
• /
• pp.41-49
• /
• 2014

Objectives: We propose a method to model and represent formulas in Korean medicine information systems. Methods: All the formulas were codified in the form of graphs representing the relationship between a formula and its constituents. To identify a unique formula in a graph, the formula's name, the book in which the formula was written, the book where the formula was extracted, and the page number in the extracted book are used. All the formulas and the relationship between formulas are modelled as an ontology based on graphs. Results: A formula search system was constructed using our ontology, which can represent formula information efficiently by grouping and filtering of formulas. Our formula model was also constructed as a mobile application. Conclusions: The information in our formula search system depends on our ontology. However, our model or our search scenarios could be extended according to formula information.

• 대한한의학원전학회지
• /
• 제31권4호
• /
• pp.69-78
• /
• 2018

Objectives : The aim of this study was to diversify the interpretation of formulas used for insomnia treatment by searching and analyzing herbal combinations in formulas used for insomnia treatment in Korean medicine. Methods : Frequency analysis was conducted on herbal combinations of 255 formulas related with insomnia, along with network analysis using Netminer 4.2.1. Results : This study has found herbal combinations used frequently in Korean medicine formulas used for insomnia treatment, and a result of network analysis composed of four communities. Each community consisted of herbs in affiliation of Yookmijihwangtang(六味地黃湯) and Samultang(四物湯), Bohyulchunghwatang(補血淸火湯) and Ondamtang(溫膽湯), Jungjihwan(定志丸) and Sanjointang(酸棗仁湯). Conclusions : This study could help in assisting researchers to diversify formula analysis in future studies. Moreover, the herbal combination in insomnia formulas could be used to search for insomnia formulas in other databases or creating a new prescription.

• 한국항만학회지
• /
• 제15권1호
• /
• pp.87-97
• /
• 2001

The calculation of earthwork plays a major role in plan or design of many civil engineering projects, and thus it has become very important to advanced the accuracy of earthwork calculation. Current method used for estimating the volume of pit excavation assumes that the ground profile between the grid points is linear(trapezoidal rule), or nonlinear(simpson's formulas). In this paper the spot height method, least square method, and chamber formulas, Chen and Lin method are compared with the volumes of the pits in these examples. As a result of this study, algorithm of chen and Lin me쇙 by spline method should provide a better accuracy than the spot height method, least square method, chamber formulas. The Chen and Lin formulas can be used for estimating the excavation volume of a pit divide into a grid with unequal intervals. From the characteristics of the cubic spline polynomial, the modeling curve of the Chen and Lin method is smooth and matches the ground profile well. Generally speaking, the nonlinear profile formulas provide better accuracy than the linear profile formulas. The mathematical model mentioned make an offer maximum accuracy in estimating the volume of a pit excavation.

• Smart Structures and Systems
• /
• 제17권2호
• /
• pp.231-256
• /
• 2016

This study concerns the derivation of optimum tuning formulas for a passive Tuned Mass Damper (TMD) device, for the case of benchmark ideal excitations acting on a single-degree-of-freedom (SDOF) damped primary structure. The free TMD parameters are tuned first through a non-linear gradient-based optimisation algorithm, for the case of harmonic or white noise excitations, acting either as force on the SDOF primary structure or as base acceleration. The achieved optimum TMD parameters are successively interpolated according to appropriate analytical fitting proposals, by non-linear least squares, in order to produce simple and effective TMD tuning formulas. In particular, two fitting models are presented. The main proposal is composed of a simple polynomial relationship, refined within the fitting process, and constitutes the optimum choice. A second model refers to proper modifications of literature formulas for the case of an undamped primary structure. The results in terms of final (interpolated) optimum TMD parameters and of device effectiveness in reducing the structural dynamic response are finally displayed and discussed in detail, showing the wide and ready-to-use validity of the proposed optimisation procedure and achieved tuning formulas. Several post-tuning trials have been carried out as well on SDOF and MDOF shear-type frame buildings, by confirming the effective benefit provided by the proposed optimum TMD.

• 대한한의학회지
• /
• 제44권3호
• /
• pp.29-38
• /
• 2023

Objectives: This study aimed to investigate the acute oral toxicity of 77 herbal formulas and performed in male and female Sprague-Dawley (SD) rats as per the guidelines mentioned in Ministry of Food and Drug Safety. Methods: Each sex of SD rat were administered a single dose (2000 or 5000 mg/kg) of 77 herbal formulas via oral gavage; the control group received vehicle only. After administration, the mortality, clinical signs, gross findings, and body weight were followed up for 15 days. Results: After administration of 77 herbal formulas, mortality, clinical signs, body weight changes, and gross findings related to the test substances were not observed in both male and female groups. Conclusion: Our results demonstrate the single-dose oral administration of 77 herbal formulas produced no mortality indicating the approximate lethal dose is greater than 2000 or 5000 mg/kg body weight.