• Title, Summary, Keyword: curve expression

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A Determination of the Rainfall Durations of Various Recurrence Intervals (재현기간별 설계유효우량의 지속기간결정)

  • 윤용남;전병호
    • Water for future
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    • v.12 no.2
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    • pp.56-62
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    • 1979
  • Many methods of estimating design floods from rainfall data involve a trial and error procedure to determine the duration of the design rainfall, which is very complicated and time-consuming. In this study, an effort was given to derive an analytical expression for estimating the appropriate duration for use with a particular unit hydrograph. According to the so-derived analytical expression the coordinateds of hvdrograph curve and rainfall curve for the Musim Representative Basin were computed and then plotted on a same scal graph paper on which the critical durations of design rainfall excess of various recurrence intervals were determined by the point of intersection of the tow curves.

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Explicit Matrix Expressions of Progressive Iterative Approximation

  • Chen, Jie;Wang, Guo-Jin
    • International Journal of CAD/CAM
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    • v.13 no.1
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    • pp.1-11
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    • 2013
  • Just by adjusting the control points iteratively, progressive iterative approximation (PIA) presents an intuitive and straightforward scheme such that the resulting limit curve (surface) can interpolate the original data points. In order to obtain more flexibility, adjusting only a subset of the control points, a new method called local progressive iterative approximation (LPIA) has also been proposed. But to this day, there are two problems about PIA and LPIA: (1) Only an approximation process is discussed, but the accurate convergence curves (surfaces) are not given. (2) In order to obtain an interpolating curve (surface) with high accuracy, recursion computations are needed time after time, which result in a large workload. To overcome these limitations, this paper gives an explicit matrix expression of the control points of the limit curve (surface) by the PIA or LPIA method, and proves that the column vector consisting of the control points of the PIA's limit curve (or surface) can be obtained by multiplying the column vector consisting of the original data points on the left by the inverse matrix of the collocation matrix (or the Kronecker product of the collocation matrices in two direction) of the blending basis at the parametric values chosen by the original data points. Analogously, the control points of the LPIA's limit curve (or surface) can also be calculated by one-step. Furthermore, the $G^1$ joining conditions between two adjacent limit curves obtained from two neighboring data points sets are derived. Finally, a simple LPIA method is given to make the given tangential conditions at the endpoints can be satisfied by the limit curve.

A Study on the Application of S-curve for Basic Plan in a Shipbuilding Yard (조선 기본계획을 위한 S-커브 활용에 관한 연구)

  • Park, Ju-Chull;Lee, Kang-Ryol;Moon, Dong-Ug;Song, Chi-Oun
    • IE interfaces
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    • v.7 no.3
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    • pp.201-212
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    • 1994
  • In this paper, we develop computerized procedures of the S-Curve, the cumulative progress rates of load input, applied to shipbuilding basic plan. For a real world ship yard, we study the application related problems and develop more efficient procedures of applying the curves in terms of usability and computerization. The yard currently do not have any mathematical expression for the S-Curve. They express the curves using data tables which represents data points of the manually drafted S-Curve graphs, which causes the difficulties in efficient computerization. Another problem the yard has is the lack of the feedback procedure of the actual load different from the initial plan. Due to those problems, the application procedures of the S-Curve require much time and endeavor amounting two full time employees. To resolve the problems, we develop the mathematical expression of the S-Curve using beta distribution function and the feedback procedure regenerating the planned load reflecting the difference between the initial plan and its realization. To build user friendly program, the graphic user interface is also developed using OSF/MOTIF toolkits. Through the development, we reduce the burden required in applying the curves to a part-time job of one employee.

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Human Emotion Recognition based on Variance of Facial Features (얼굴 특징 변화에 따른 휴먼 감성 인식)

  • Lee, Yong-Hwan;Kim, Youngseop
    • Journal of the Semiconductor & Display Technology
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    • v.16 no.4
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    • pp.79-85
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    • 2017
  • Understanding of human emotion has a high importance in interaction between human and machine communications systems. The most expressive and valuable way to extract and recognize the human's emotion is by facial expression analysis. This paper presents and implements an automatic extraction and recognition scheme of facial expression and emotion through still image. This method has three main steps to recognize the facial emotion: (1) Detection of facial areas with skin-color method and feature maps, (2) Creation of the Bezier curve on eyemap and mouthmap, and (3) Classification and distinguish the emotion of characteristic with Hausdorff distance. To estimate the performance of the implemented system, we evaluate a success-ratio with emotional face image database, which is commonly used in the field of facial analysis. The experimental result shows average 76.1% of success to classify and distinguish the facial expression and emotion.

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A Proposal on the Stress-Strain Curve of Stainless Steel STS 304 (STS 304 스테인리스강의 응력도-변형도 곡선에 관한 제안)

  • Shin, Tae Song
    • Journal of Korean Society of Steel Construction
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    • v.18 no.2
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    • pp.271-278
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    • 2006
  • This paper is to investigate into the stress-strain curves for austenite stainless steel STS 304 over the full strain range. The Ramberg-Osgood expression is useful up to the beyond the0.2% proof stress in the ultimate state. The Rasmussen curve has developed for stresses beyond 0.2% proof stress, based on the Ramberg-Osgood concept. These expressed curves don't good agree with the test results. It is here proposed the based on the analysis of the test results better curve.

Upregulation of the RNF8 gene can predict the presence of sperm in azoospermic individuals

  • Nazari, Majid;Babakhanzadeh, Emad;Zarch, Mohsen Aghaei;Talebi, Mehrdad;Narimani, Nima;Dargahi, Mandana;Sabbaghian, Marjan;Ghasemi, Nasrin
    • Clinical and Experimental Reproductive Medicine
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    • v.47 no.1
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    • pp.61-67
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    • 2020
  • Objective: In this study, specimens from testicular biopsies of men with nonobstructive azoospermia (NOA) were used to investigate whether RNF8 gene could serve as a biomarker to predict the presence of sperm in these patients. Methods: Testicular biopsy specimens from 47 patients were classified according to the presence of sperm (positive vs. negative groups) and investigated for the expression of RNF8. The level of RNF8 gene expression in the testes was compared between these groups using reverse-transcription polymerase chain reaction. Results: The expression level of RNF8 was significantly higher in testicular samples from the positive group than in those from the negative group. Moreover, the area under the curve of RNF8 expression for the entire study population was 0.84, showing the discriminatory power of RNF8 expression in differentiating between the positive and negative groups of men with NOA. A receiver operating characteristic curve analysis showed that RNF8 expression had a sensitivity of 81% and a specificity of 84%, with a cutoff level of 1.76. Conclusion: This study points out a significant association between the expression of RNF8 and the presence of sperm in NOA patients, which suggests that quantified RNF8 expression in testicular biopsy samples may be a valuable biomarker for predicting the presence of spermatozoa in biopsy samples.

The solar cell modeling using Lambert W-function (Lambert W 함수를 이용한 태양전지 모델링)

  • Bae, Jong-Guk;Kang, Gi-Hwan;Kim, Kyung-Soo;Yu, Gwon-Jong;Ahn, Hyung-Geun;Han, Deuk-Young
    • 한국태양에너지학회:학술대회논문집
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    • pp.278-281
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    • 2011
  • This system can predict the maximum output about all illumination levels so that the PV system designer can design the system having the best efficiency. For the output prediction exact about the solar cell, that is the device the basis most in the PV system, the basis has to be in order to try this way. The solution based on Lambert W-function are presented to express the transcendental current-voltage characteristic containing parasitic power consuming parameters like series and shunt resistances. A simple and efficient method for the extraction of a single current-voltage (I-V) curve under the constant illumination level is proposed. With the help of the Lambert W function, the explicit analytic expression for I is obtained. And the explicit analytic expression for V is obtained. This analytic expression is directly used to fit the experimental data and extract the device parameters. The I-V curve of the solar cell was expressed through the modeling using Lambert W-function and the numerical formula where there is the difficulty could be logarithmically expressed This method expresses with the I-V curve through the modeling using Lambert W-function which adds other loss ingredients to the equation2 as to the research afterward. And the solar cell goes as small and this I-V curve can predict the power penalty in the system unit.

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A Study on the Characteristics of Abstractive Form Expression in Contemporary Housing Architectures (현대 주거건축에 있어서 추상적 형태 표현 특성에 관한 연구)

  • Jang Hoon-Ick
    • Journal of the Korean housing association
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    • v.15 no.6
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    • pp.15-25
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    • 2004
  • This study examined how the characteristics of abstractive form among various contenporary housing architecture have been expressed. The conclusions were: First, abstractive characteristics and types related to from expression of contemporary housing architectures were minimal form and absolute form of geometrical abstraction, plastic form and atypical form of expressive abstraction and mechanical aesthetics of industrial abstraction. Second, the typological form expression characteristics in minimal expression related to geometrical abstraction were simplicity, purity, and the properties of matter, and the characteristics in absolute expression were overlapping, obliqueness and dispensability. On the other hand, plasticity and mobility of materials were distinctive in plastic form expression, and inclination, curve and asymmetry were distinctive in atypical expression. The distinctive nature of mechanical aesthetics related to industrial abstraction included transparency, simplicity and. the properties of matter Funhermore, the study aimed at the understanding of various from expressions showed up in contemporary housing architecture, revealing the aspects of abstractive form expression characteristics.

IMPLICITIZATION OF RATIONAL CURVES AND POLYNOMIAL SURFACES

  • Yu, Jian-Ping;Sun, Yong-Li
    • Bulletin of the Korean Mathematical Society
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    • v.44 no.1
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    • pp.13-29
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    • 2007
  • In this paper, we first present a method for finding the implicit equation of the curve given by rational parametric equations. The method is based on the computation of $Gr\"{o}bner$ bases. Then, another method for implicitization of curve and surface is given. In the case of rational curves, the method proceeds via giving the implicit polynomial f with indeterminate coefficients, substituting the rational expressions for the given curve and surface into the implicit polynomial to yield a rational expression $\frac{g}{h}$ in the parameters. Equating coefficients of g in terms of parameters to 0 to get a system of linear equations in the indeterminate coefficients of polynomial f, and finally solving the linear system, we get all the coefficients of f, and thus we obtain the corresponding implicit equation. In the case of polynomial surfaces, we can similarly as in the case of rational curves obtain its implicit equation. This method is based on characteristic set theory. Some examples will show that our methods are efficient.