• 제목/요약/키워드: Equilibrium function

검색결과 703건 처리시간 0.028초

A Genetic Algorithm for Trip Distribution and Traffic Assignment from Traffic Counts in a Stochastic User Equilibrium

  • Sung, Ki-Seok;Rakha, Hesham
    • Management Science and Financial Engineering
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    • 제15권1호
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    • pp.51-69
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    • 2009
  • A network model and a Genetic Algorithm (GA) is proposed to solve the simultaneous estimation of the trip distribution and traffic assignment from traffic counts in the congested networks in a logit-based Stochastic User Equilibrium (SUE). The model is formulated as a problem of minimizing a non-linear objective function with the linear constraints. In the model, the flow-conservation constraints are utilized to restrict the solution space and to force the link flows become consistent to the traffic counts. The objective of the model is to minimize the discrepancies between two sets of link flows. One is the set of link flows satisfying the constraints of flow-conservation, trip production from origin, trip attraction to destination and traffic counts at observed links. The other is the set of link flows those are estimated through the trip distribution and traffic assignment using the path flow estimator in the logit-based SUE. In the proposed GA, a chromosome is defined as a real vector representing a set of Origin-Destination Matrix (ODM), link flows and route-choice dispersion coefficient. Each chromosome is evaluated by the corresponding discrepancies. The population of the chromosome is evolved by the concurrent simplex crossover and random mutation. To maintain the feasibility of solutions, a bounded vector shipment technique is used during the crossover and mutation.

Real Exchange Rate Misalignment and Economic Fundamentals in Korea

  • Keun Yeong Lee
    • East Asian Economic Review
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    • 제28권3호
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    • pp.277-314
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    • 2024
  • This study analyzes the response of economic fundamentals to a misalignment shock of the real effective exchange rate in Korea. The estimation results of the equilibrium exchange rate determination model and time series model show that there is no significant difference in the direction of the deviation from equilibrium and that the won is significantly undervalued during the period before 1988, or during the currency and global financial crises. The cumulative impulse response analysis of the VAR model over the full period shows that an upward shock to the deviation from the equilibrium exchange rate reduces the GDP gap and inflation rate, while the effect on the call rate is not statistically significant. Furthermore, an upward misalignment shock initially worsens the goods and services balance, but the deficit in the goods and services balance shrinks significantly over time. In rolling regressions analysis, the entire sample is divided into two periods to estimate the impulse response function from the first period, and then the same procedure is repeated by moving the sample forward one by one. The cumulative impulse response results show that, as is the case for the full period, a positive exchange rate misalignment shock initially reduces the GDP gap, inflation, and worsens the goods and services balance, but the impact of this upward shock on these variables becomes increasingly weaker in the more recent sample. It also shows that the negative impact of upward shocks on the current account is smoothed out more recently during periods of undervaluation than during periods of overvaluation.

$SiH_4$ 가스의 에너지 분포함수 관한 연구 (Analysis of Energy Distribution Function in $SiH_4$ Gas)

  • 성낙진;김상남
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 학술대회 논문집 전문대학교육위원
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    • pp.76-79
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    • 2001
  • Energy distribution function in $SiH_4$ has been analysed over the E/N range $0.5{\sim}300Td$ and Pressure value 0.5, 1.0, 2.5 Torr by a two-term approximation Boltzmann equation method and by a Monte Carlo simulation. The motion has been calculated to give swarm parameters for the electron drift velocity, diffusion coefficient, electron ionization, mean energy and the electron energy distribution function. The electron energy distribution function has been analysed in $SiH_4$ at E/N=30, 50Td for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections.

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Equilibrium shape analysis of single layer structure by measure potential function

  • Ijima, Katsushi;Xi, Wei;Goto, Shigeo
    • Structural Engineering and Mechanics
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    • 제5권6호
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    • pp.775-784
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    • 1997
  • A unified theory is presented for the shape analysis of curved surface with a single layer structure composed by frame, membrane or shell. The shapes produced by the theory have no shear stress in elements, and the stress states in the whole shape are as uniform as possible under an ordinary load. The theory starts from defining an element potential function expressed by the measurement of the element length or the element area. Therefore, the shape analysis can produce various forms according to the definition of the potential function, and each of those form or the cable net form with the potential function of the second power of element length is simply gotten by the linear analysis. The form in tensile stress is mechanically equal to an isotropic tension form.

Control-to-output Transfer Function of the Open-loop Step-up Converter in CCM Operation

  • Wang, Faqiang;Ma, Xikui
    • Journal of Electrical Engineering and Technology
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    • 제9권5호
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    • pp.1562-1568
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    • 2014
  • Based on the average method and the geometrical technique to calculate the average value, the average model of the open-loop step-up converter in CCM operation is established. The DC equilibrium point and corresponding small signal model is derived. The control-to-output transfer function is presented and analyzed. The theoretical analysis and PSIM simulations shows that the control-to-output transfer function includes not only the DC input voltage and the DC duty cycle, but also the two inductors, the two energy-transferring capacitors, the switching frequency and the load. Finally, the hardware circuit is designed, and the circuit experimental results are given to confirm the effectiveness of theoretical derivations and analysis.

Stability of superconductor by integration formula

  • Seol, S.Y.
    • 한국초전도ㆍ저온공학회논문지
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    • 제21권3호
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    • pp.1-5
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    • 2019
  • The superconductor stability theories are consistently described by the integral formula. If the defined stability function is a simple decreasing function, it becomes a cryogenic stability condition. If the stability function has a maximum value and a minimum value, and the maximum value is less than 0, then it is a cold-end recovery condition. If the maximum value is more than 0, it can be shown that the unstable equilibrium temperature, that is, the MPZ (minimum propagation zone) temperature distribution can exist. The MPZ region is divided into two regions according to the current ratio. At the low current ratio, the maximum dimensionless temperature is greater than 1, and at the relatively high current ratio, the maximum dimensionless temperature is less than 1. In order to predict the minimum quench energy, the dimensionless energy was obtained for the MPZ temperature distribution. In particular, it was shown that the dimensionless energy can be obtained even when the MPZ maximum temperature is 1 or more.

ON THE GENOTYPE FREQUENCIES AND GENERATING FUNCTION FOR FREQUENCIES IN A DYPLOID MODEL

  • Choi, Won
    • Korean Journal of Mathematics
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    • 제29권1호
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    • pp.75-80
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    • 2021
  • For a locus with two alleles (IA and IB), the frequencies of the alleles are represented by $$p=f(I^A)={\frac{2N_{AA}+N_{AB}}{2N} },\;q=f(I^B)={\frac{2N_{BB}+N_{AB}}{2N}}$$ where NAA, NAB and NBB are the numbers of IA IA, IA IB and IB IB respectively and N is the total number of populations. The frequencies of the genotypes expected are calculated by using p2, 2pq and q2. So in this paper, we consider the method of whether some genotypes is in Hardy-Weinburg equilibrium. Also we calculate the probability generating function for the offspring number of genotype produced by a mating of the ith male and jth female under a diploid model of N population with N1 males and N2 females. Finally, we have conditional joint probability generating function of genotype frequencies.

초과엔탈피 화염의 점근 해석 (An Asymptotic Analysis of Excess Enthalpy Flame)

  • 이대근
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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    • pp.135-137
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    • 2014
  • Excess enthalpy flame propagating an porous inert medium, which recirculate exhaust heat to the upstream cold mixture, is theoretically analyzed. Using the activation-energy asymptotics, the flame structure is divided into the thin reaction and the gas-phase preheat zone, as is traditionally done. Ahead and behind of the two, there exist an outer preheat zone, where heat is convectively transferred from solid to gas, and a downstream re-equilibrium zone, where thermal equilibrium between phases is established. Asymptotic solutions of species and energy equations in each zone are obtained and then matched to each other, and finally the mass burning rate is obtained as a function of the flame propagation velocity with respect to the solid phase and physical properties of gas and solid.

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고정화제와 고정화된 해조류에 의한 납의 제거 특성 (Removal Characteristics of Lead by Immobilizing Agents and Immobilized Seaweed)

  • 이학성;서정호;서근학
    • 한국환경보건학회지
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    • 제27권1호
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    • pp.83-87
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    • 2001
  • In this study, the characteristics of lead removal by PVA and alginate bead which used widely as immobilizing agents were investigated, and the difference of removal amounts between pure PVA/alginate bead and Sargassum thunbergii immobilized bead was studied. All PVA beads, pure and S. thunbergii immobilized, reached an equilibrium state in about 1 hour, and S. thunbergii immobilized bead adsorbed more lead than pure one. But in the case of alginate beads, they needed much time, about 5 hours, to reach an equilibrium state, and adsorbed lead four times higher than PVA beads. Therefore, it was considered that alginate beads had more mass transfer resistance and function groups which adsorb lead such as hydroxyl, carboxyl and etc. than PVA bead. To examine the continuous usage of alginate beads, the process of adsorption/desorption of lead was conducted repeatedly. As the process proceeded, the amounts of lead adsorption decrease, so it was indicated that the non-desorbed lead from alginate bead at first adsorption/desorption process remained constantly.

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Defect Chemistry of BaTiO_3$ Codoped with Mn and Nb

  • Han, Young-Ho;Shin, Dong-Jin
    • The Korean Journal of Ceramics
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    • 제4권2호
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    • pp.68-71
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    • 1998
  • The effect of Mn and Nb additions on the electrical properties of BaTiO$_3$ has been studied by means of equilibrium electrical conductivity as a function of temperature, oxygen partial pressure(Po$_2$) and composition. If the manganese ion is added to the normal Ti site, i.e. BaTi$_{1-x}Mn_xO_{\delta-6}$, the equilibrium conductivity shows strong evidence of acceptor-doped behavior. The conductivity minimum, corresponding to the transition from oxygen excess, p-type behavior to oxygen deficient, n-type behavior with decreasing Po$_2$, is displaced to lower Po$_2$ and is broadened and flattened. The partial replacement of Mn ion with Nb decreases the acceptor-doped effect and the total replacement exhibits a typical donor-doped behavior. It was confirmed that unlike undoped or other acceptor-doped behavior. It was confirmed that unlike undoped or other acceptor-doped samples, for the p-type region, the electrical conductivity follows the 1/6th power dependence of oxygen partial pressure.

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