• Title/Summary/Keyword: Rational Function Model

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Multimedia Service Discrimination Based on Fair Resource Allocation Using Bargaining Solutions

  • Shin, Kwang-Sup;Jung, Jae-Yoon;Suh, Doug-Young;Kang, Suk-Ho
    • ETRI Journal
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    • v.34 no.3
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    • pp.341-351
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    • 2012
  • We deal with a resource allocation problem for multimedia service discrimination in wireless networks. We assume that a service provider allocates network resources to users who can choose and access one of the discriminated services. To express the rational service selection of users, the utility function of users is devised to reflect both service quality and cost. Regarding the utility function of a service provider, total profit and efficiency of resource usage have been considered. The proposed service discrimination framework is composed of two game models. An outer model is a repeated Stackelberg game between a service provider and a user group, while an inner model is a service selection game among users, which is solved by adopting the Kalai-Smorodinsky bargaining solution. Through simulation experiments, we compare the proposed framework with existing resource allocation methods according to user cost sensitivity. The proposed framework performed better than existing frameworks in terms of total profit and fairness.

Investigation on spanwise coherence of buffeting forces acting on bridges with bluff body decks

  • Zhou, Qi;Zhu, Ledong;Zhao, Chuangliang;Ren, Pengjie
    • Wind and Structures
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    • v.30 no.2
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    • pp.181-198
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    • 2020
  • In the traditional buffeting response analysis method, the spanwise incomplete correlation of buffeting forces is always assumed to be same as that of the incident wind turbulence and the action of the signature turbulence is ignored. In this paper, three typical bridge decks usually adopted in the real bridge engineering, a single flat box deck, a central slotted box deck and a two-separated paralleled box deck, were employed as the investigated objects. The wind induced pressure on these bridge decks were measured via a series of wind tunnel pressure tests of the sectional models. The influences of the wind speed in the tests, the angle of attack, the turbulence intensity and the characteristic distance were taken into account and discussed. The spanwise root coherence of buffeting forces was also compared with that of the incidence turbulence. The signature turbulence effect on the spanwise root coherence function was decomposed and explained by a new empirical method with a double-variable model. Finally, the formula of a sum of rational fractions that accounted for the signature turbulence effect was proposed in order to fit the results of the spanwise root coherence function. The results show that, the spanwise root coherence of the drag force agrees with that of incidence turbulence in some range of the reduced frequency but disagree in the mostly reduced frequency. The spanwise root coherence of the lift force and the torsional moment is much larger than that of the incidence turbulence. The influences of the wind speed and the angle of attack are slight, and they can be ignored in the wind tunnel test. The spanwise coherence function often involves several narrow peaks due to the signature turbulence effect in the high reduced frequency zone. The spanwise coherence function is related to the spanwise separation distance and the spanwise integral length scales, and the signature turbulence effect is related to the deck-width-related reduced frequency.

KOMPSAT-2 Direct Sensor Modeling and Geometric Accuracy Analysis (다목적실용위성2호 센서모델링 및 기하정확도 분석)

  • Seo, Doo-Chun;Kim, Moon-Gyu;Lee, Dong-Han;Song, Jeong-Heon;Park, Su-Young;Lim, Hyo-Suk;An, Gi-Won;Lee, Hyo-Seong
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2007.04a
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    • pp.149-152
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    • 2007
  • The horizontal geo-location accuracy of KOMPSAT-2, without GCPs (Ground Control Points) is 80 meters CE90 for monoscopic image of up to 26 degrees off-nadir angle, after processing including POD (Precise Orbit Determination), PAD(Precise Attitude Determination) and AOCS (Attitude and Orbit Control Subsystem) sensor calibration. In case of multiple stereo images, without GCPs, the vertical geometric accuracy is less than 22.4 meters LE 90 and the horizontal geometric accuracy is less than 25.4 meters. There are two types of sensor model for KOMPSAT-2, direct sensor model and Rational Function Model (RFM). In general, a sensor model relates object coordinates to image coordinates The major objective of this investigation is to check and verify the geometrical performance when initial KOMPSAT-2 images are employed and briefly introduce the sensor model of KOMPSAT-2.

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A Study on the Systematic Approach for the Management Science Implementation (경영과학의 실행을 위한 체계적 접근에 관한 고찰)

  • 김민성
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.9 no.13
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    • pp.51-61
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    • 1986
  • The management science was concerned about how to use the main point of the management science model and it's technique by the rational primary factors. The problem's definition, estabilished of the model and it's solving. These function are very difficult and important problems, what is more important, are the model of management science's real prosecution to the manager and management scientist. The management science give us a clue to the solution of a business problem. To get needs conclusion and achieving the estabilished object, we must implement a plan, a stratgem, a policy. If we were not implementing the recommended items, we may call the estabilished model and problem solving impractical, ivory-tower theorizing. But, the implementation of management science model is a complicated problem that is involved mutual relations of managers and management scientist, linkage parts member and the resources of organization. And the other problems of implementation are very complicated problems composed of technologic and economic, social and politic, psychological. This paper reports the implementation of a success that possibly studies a fluent and a chief cause to systematic analysis. Then, first of all I will define of implementation and from these, construction of a unity system, I continue with a catch hold of a main point and a fluent for the successful implementation.

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Development of Weigh Calculation Method for Pavement Roughness Index Considering Vehicle Wandering Distribution (원더링 분포를 고려한 도로포장 평탄성 지수의 가중치 산정기법 개발)

  • Lee, Jaehoon;Sohn, Ducksu;Park, Jejin;Cho, Yoonho
    • International Journal of Highway Engineering
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    • v.19 no.5
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    • pp.89-96
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    • 2017
  • PURPOSES: This study aims to develop a rational procedure for estimating the pavement roughness index considering vehicle wandering. METHODS : The location analysis of the passing vehicle in the lane was performed by approximately 1.2 million vehicles for verification of the wandering distribution. According to verification result, the distribution follows the normal distribution pattern. The probability density function was estimated using each lane's wandering distribution model. Then the procedure for applying a weighted value into the lane profile was conducted using this function. RESULTS : The modified index, MRIw, with consideration towards applying the wandering weighted value application was computed then compared with MRI. It was found that the Coefficient of Variation for distribution of lateral roughness index in the lane was high in the case of a large difference between each index (i.e., MRIw and MRI) observed. CONCLUSIONS : This result confirms that the new procedure with consideration of the weight factor can successfully improve the lane representative characteristics of the roughness index.

Modeling of AA5052 Sheet Incremental Sheet Forming Process Using RSM-BPNN and Multi-optimization Using Genetic Algorithms (반응표면법-역전파신경망을 이용한 AA5052 판재 점진성형 공정변수 모델링 및 유전 알고리즘을 이용한 다목적 최적화)

  • Oh, S.H.;Xiao, X.;Kim, Y.S.
    • Transactions of Materials Processing
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    • v.30 no.3
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    • pp.125-133
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    • 2021
  • In this study, response surface method (RSM), back propagation neural network (BPNN), and genetic algorithm (GA) were used for modeling and multi-objective optimization of the parameters of AA5052-H32 in incremental sheet forming (ISF). The goal of optimization is to determine the maximum forming angle and minimum surface roughness, while varying the production process parameters, such as tool diameter, tool spindle speed, step depth, and tool feed rate. A Box-Behnken experimental design (BBD) was used to develop an RSM model and BPNN model to model the variations in the forming angle and surface roughness based on variations in process parameters. Subsequently, the RSM model was used as the fitness function for multi-objective optimization of the ISF process the GA. The results showed that RSM and BPNN can be effectively used to control the forming angle and surface roughness. The optimized Pareto front produced by the GA can be utilized as a rational design guide for practical applications of AA5052 in the ISF process

Design, Analysis, and Equivalent Circuit Modeling of Dual Band PIFA Using a Stub for Performance Enhancement

  • Yousaf, Jawad;Jung, Hojin;Kim, Kwangho;Nah, Wansoo
    • Journal of electromagnetic engineering and science
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    • v.16 no.3
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    • pp.169-181
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    • 2016
  • This work presents a new method for enhancing the performance of a dual band Planer Inverted-F Antenna (PIFA) and its lumped equivalent circuit formulation. The performance of a PIFA in terms of return loss, bandwidth, gain, and efficiency is improved with the addition of the proposed open stub in the radiating element of the PIFA without disturbing the operating resonance frequencies of the antenna. In specific cases, various simulated and fabricated PIFA models illustrate that the return loss, bandwidth, gain, and efficiency values of antennas with longer optimum open stub lengths can be enhanced up to 4.6 dB, 17%, 1.8 dBi, and 12.4% respectively, when compared with models that do not have open stubs. The proposed open stub is small and does not interfere with the surrounding active modules; therefore, this method is extremely attractive from a practical implementation point of view. The second presented work is a simple procedure for the development of a lumped equivalent circuit model of a dual band PIFA using the rational approximation of its frequency domain response. In this method, the PIFA's measured frequency response is approximated to a rational function using a vector fitting technique and then electrical circuit parameters are extracted from it. The measured results show good agreement with the electrical circuit results. A correlation study between circuit elements and physical open stub lengths in various antenna models is also discussed in detail; this information could be useful for the enhancement of the performance of a PIFA as well as for its systematic design. The computed radiated power obtained using the electrical model is in agreement with the radiated power results obtained through the full wave electromagnetic simulations of the antenna models. The presented approach offers the advantage of saving computation time for full wave EM simulations. In addition, the electrical circuit depicting almost perfect characteristics for return loss and radiated power can be shared with antenna users without sharing the actual antenna structure in cases involving confidentiality limitations.

Probability of performance failure of storm sewer according to accumulation of debris (토사 적체에 따른 우수관의 성능불능확률)

  • Kwon, Hyuk-Jae
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.5
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    • pp.509-517
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    • 2010
  • Statistical distribution of annual maximum rainfall intensity of 18 cities in Korea was analyzed and applied to the reliability model which can calculate the probability of performance failure of storm sewer. After the analysis, it was found that distribution of annual maximum rainfall intensity of 18 cities in Korea is well matched with Gumbel distribution. Rational equation was used to estimate the load and Manning's equation was used to estimate the capacity in reliability function to calculate the probability of performance failure of storm sewer. Reliability analysis was performed by developed model applying to the real storm sewer. It was found that probability of performance failure is abruptly increased if the diameter is smaller than certain size. Therefore, cleaning the inside of storm sewer to maintain the original diameter can be one of the best ways to reduce the probability of performance failure. In the present study, probability of performance failure according to accumulation of debris in storm sewer was calculated. It was found that increasing the amount of debris seriously decrease the capacity of storm sewer and significantly increase the probability of performance failure.

Development of Continuous Rainfall-Runoff Model for Flood Forecasting on the Large-Scale Basin (대유역 홍수예측을 위한 연속형 강우-유출모형 개발)

  • Bae, Deg-Hyo;Lee, Byong-Ju
    • Journal of Korea Water Resources Association
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    • v.44 no.1
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    • pp.51-64
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    • 2011
  • The objective of this study is to develop a continuous rainfall-runoff model for flood prediction on a large-scale basin. For this study, the hourly surface runoff estimation method based on the variable retention parameter and runoff curve number is developed. This model is composed that the soil moisture to continuous rainfall can be simulated with applying the hydrologic components to the continuous equation for soil moisture. The runoff can be simulated by linking the hydrologic components with the storage function model continuously. The runoff simulation to large basins can be performed by using channel storage function model. Nakdong river basin is selected as the study area. The model accuracy is evaluated at the 8 measurement sites during flood season in 2006 (calibration period) and 2007~2008 (verification period). The calibrated model simulations are well fitted to the observations. Nash and Sutcliffe model efficiencies in the calibration and verification periods exist in the range of 0.81 to 0.95 and 0.70 to 0.94, respectively. The behavior of soil moisture depending on the rainfall and the annual loadings of simulated hydrologic components are rational. From this results, continuous rainfall-runoff model developed in this study can be used to predict the discharge on large basins.

Accurate FDTD Dispersive Modeling for Concrete Materials

  • Chung, Haejun;Cho, Jeahoon;Ha, Sang-Gyu;Ju, Saehoon;Jung, Kyung-Young
    • ETRI Journal
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    • v.35 no.5
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    • pp.915-918
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    • 2013
  • This work presents an accurate finite-difference time-domain (FDTD) dispersive modeling of concrete materials with different water/cement ratios in 50 MHz to 1 GHz. A quadratic complex rational function (QCRF) is employed for dispersive modeling of the relative permittivity of concrete materials. To improve the curve fitting of the QCRF model, the Newton iterative method is applied to determine a weighting factor. Numerical examples validate the accuracy of the proposed dispersive FDTD modeling.