• Title, Summary, Keyword: horizon size

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The Guaranteed Bound of Horizon Size for the Stabilizing Receding Horizon Control

  • Quan, ZhongHua;Han, Soo-Hee;Kwon, Wook-Hyun
    • 제어로봇시스템학회:학술대회논문집
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    • pp.429-432
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    • 2004
  • In this paper, we derive the guaranteed bound of the horizon size for the stabilizing receding horizon control(RHC). From the convergence property of the solution to the Riccati equation, it is shown that the lower bound can be represented in terms of the parameters in the given system model, which makes an off-line calculation possible. Additionally, it is shown to be able to obtain the stabilizing RHC without respect to the final weighting matrix. The proposed guaranteed bound is obtained numerically via simulation.

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A Suboptimal Algorithm of the Optimal Bayesian Filter Based on the Receding Horizon Strategy

  • Kim, Yong-Shik;Hong, Keum-Shik
    • International Journal of Control, Automation, and Systems
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    • v.1 no.2
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    • pp.163-170
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    • 2003
  • The optimal Bayesian filter for a single target is known to provide the best tracking performance in a cluttered environment. However, its main drawback is the increase in memory size and computation quantity over time. In this paper, the inevitable predicament of the optimal Bayesian filter is resolved in a suboptimal fashion through the use of a receding horizon strategy. As a result, the problems of memory and computational requirements are diminished. As a priori information, the horizon initial state is estimated from the validated measurements on the receding horizon. Consequently, the suboptimal algorithm proposed allows for real time implementation.

A Frozen Time Receding Horizon Control for a Linear Discrete Time-Varying System (선형 이산 시변시스템을 위한 고정시간 이동구간 제어)

  • Oh, Myung-Hwan;Oh, Jun-Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.16 no.2
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    • pp.140-144
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    • 2010
  • In the case of a linear time-varying system, it is difficult to apply the conventional stability conditions of RHC (Receding Horizon Control) to real physical systems because of computational complexity comes from time-varying system and backward Riccati equation. Therefore, in this study, a frozen time RHC for a linear discrete time-varying system is proposed. Since the proposed control law is obtained by time-invariant Riccati equation solved by forward iterations at each control time, its stability can be ensured by matrix inequality condition and the stability condition based on horizon for a time-invariant system, and they can be applied to real physical systems effectively in comparison with the conventional RHC.

A sensitivity analysis for the procurement of bituminous coal using the rolling horizon of an optimization model (Rolling Horizon을 적용한 발전용 유연탄 조달 최적화 모델의 민감도 분석)

  • Chang, Nam chul;Park, Hyun Ji;Hwang, Seung June
    • Journal of the Korea Management Engineers Society
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    • v.22 no.4
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    • pp.13-27
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    • 2017
  • The purpose of this study is to contribute to the cost competitiveness of domestic power generation companies against uncertainties such as raw material price volatility. Specifically, we created and analyzed scenarios based on how fluctuations in demand changes in inventory holdings, how ship size decision affects the cost of inventory, and the variations of transportation costs influences the amount of raw material to be purchased by the region. To derive the results reflecting the reality, we based on the existing optimization model on minimizing the total cost and by using the real data of a power generation company in Korea. Technically we applied a rolling horizon technique and estimated the effects of rising temperature on the amount of raw materials to be imported.

Hydraulic Characteristics of Mountainous Forest Soils in Korea and Applicability of Pedotransfer Functions

  • Jung, Kangho;Sonn, Yeonkyu;Hur, Seungoh;Ha, Sangkeun;Jung, Munho
    • Korean Journal of Soil Science and Fertilizer
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    • v.48 no.5
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    • pp.428-435
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    • 2015
  • Pedotransfer functions (PTFs) were developed for each soil horizon to estimate hydraulic characteristics of mountainous forest soils in South Korea. Twenty one dominant soil series from 8 soil catenae such as granite-originated catena and volcanic ash-originated catena were selected for the study; gravel contents of selected soils were 10% or lower. Saturated conductivity (Ks) was measured for each horizon in situ. Particle size distribution and organic matter content of each horizon were also determined. Based on correlation analysis with total data set, sand separate showed positive relationship with Ks ($r=0.24^*$) while clay separate had negative relationship with Ks ($r=-0.29^{**}$). The correlation coefficients of sand, clay, and organic matter content with Ks increased to $0.41^{**}$, $-0.67^{***}$, and $0.58^{***}$, respectively, using data from granite- or gneiss-originated catena with exception of volcanic ash-originated catena and sedimentary rock-originated catena. Determination coefficients of PTFs were 0.31 for A horizon, 0.25 for B, and 0.35 for C with all data set while those were 0.74 for A, 0.48 for B, and 0.54 for C. Organic matter was a dominant factor affecting Ks in A horizon but clay content was selected as the only factor influencing Ks in C horizon. It implies that PTFs should be developed with understanding characteristics of parent materials and horizons. Developed PTFs for granite- or gneiss-originated catena were following: A horizon: Log ($K_s{\times}10^7$) = -0.031C + 0.398OM + 3.49 B horizon: Log ($K_s{\times}10^7$) = -0.028C + 0.141OM + 4.05 C horizon: Log ($K_s{\times}10^7$) = -0.072C + 4.66 where C is clay separate (%) and OM is organic matter content ($g\;kg^{-1}$). The unit of Ks is cm $sec^{-1}$.

Preferential Flow as Tested by Breakthrough Curves of Cl- and Cu2+ from Saturated Undisturbed Soil Core Samples under Steady Flow Conditions (포화 불교란 토양시료의 Cl- 및 Cu2+ 출현곡선에 의한 preferential flow의 검증)

  • Yoo, Sun-Ho;Han, Kyung-Hwa;Ro, Hee-Myong;Han, Gwang-Hyun
    • Korean Journal of Soil Science and Fertilizer
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    • v.33 no.2
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    • pp.71-78
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    • 2000
  • Preferential flow has recently been the subject of increasing interest because these phenomena contribute to solute transport in soils. Commonly, preferential flow paths are associated with macropores or highly structured soils. We presented an analysis of the measured breakthrough curves (BTCs) of $Cl^-$ and $Cu^{2+}$ ions to test the occurrence of preferential flow in soils using miscible displacement technique under steady flow conditions. We also analyzed soil water retention curves and from this curves induced cumulative pore size distribution of undisturbed soils, which sampled from Ap1, B1, and C horizons of Songjeong series soils (the fine loamy, mesic family of Typic Hapludults). In this study, miscible displacement experiment on C horizon was excluded, because it is structureless sandy loam with saturated hydraulic conductivity of $5.2cmhr^{-1}$. The saturated hydraulic conductivity of Ap1 horizon was $2.0cmhr^{-1}$, which was about 7 times higher than that of B1 horizon ($0.27cm hr^{-1}$). Cumulative pore size distribution predicted that Ap1 horizon had more macropores (pore diameter larger than $49{\mu}m$, equivalent to -6 kpa of soil matric potential) than B1 horizon. The hydrodynamic dispersion coefficient from chloride BTCs was estimated as $1.3cm^2hr^{-1}$ for B1 and $34cm^2hr^{-1}$ for Ap1 horizon. However the retardation factors of B1 and Ap1 horizon were significantly different, i.e. 1 and 0.6, respectively, which means that there was distinct partition between mobile water and immobile phase in Ap1 horizon. The copper retardation effect of Ap1 horizon was less than that of B1 horizon, even though cation exchange capacity of Ap1 horizon was higher than that of B1 horizon. Thus, breakthrough curves of $Cl^-$ and $Cu^{2+}$ obviously showed the probability that preferential flow would occur in Ap1 horizon.

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Optimal Reporting Stategy of an Insured -Dynamic Programming Approach-

  • Min, Jae-Hyung
    • Journal of the Korean Operations Research and Management Science Society
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    • v.15 no.1
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    • pp.83-97
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    • 1990
  • We consider an insured who wishes to determine his optimal reporting strategy over a given planning horizon, when he has option of reporting of not reporting his at-fault accidents. Assuming that the premium in future period is continually adjusted by the insured's loss experience, the insured would not report every loss incurred. Rather, considering the benefits and costs of each decision, the insured may want to seek a way of optimizing his interests over the planning horizon. The situation is modeled as a dynamic programming problem. We consider an insured's discounted expected cost minimization problem, where the premium increase in future period is affected by the size of the current claim. More specifically, we examine two cases ; (1) the premium increase in the next is a linear function (a constant fraction) of the current claim size; (2) the premium increase in the next period is a concave function of the current claim size. In each case, we derive the insured's optimal reporting strategy.

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Planning Horizon Procedure for the Dynamic Lot Size Model with Multiple Production Modes (다종생산방식(多種生産方式)을 갖는 동적(動的) 롯트결정(決定) 문제(問題)에 관한 계획기간(計劃期間) 절차(節次))

  • Ro, Jae-Ho
    • Journal of Industrial Technology
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    • v.5
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    • pp.91-96
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    • 1985
  • This paper presents a problem of a Wagner-Whitin type in which there are several options for setup and production in a period. Theorems that efficiently decrease the computational effort required to find optimal policies and a Planning Horizon Theorem are developed.

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Taxonomical Classification of Jangho Series (장호통의 분류)

  • Song, Kwan-Cheol;Hyun, Byung-Geun;Sonn, Yeon-Kyu;Zhang, Yong-Seon;Park, Chan-Won
    • Korean Journal of Soil Science and Fertilizer
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    • v.42 no.5
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    • pp.330-335
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    • 2009
  • This study was conducted to reclassify Jangho series based on the second edition of Soil Taxonomy : A Basic System of Soil Classification for Making and Interpreting Soil Surveys. Morphological properties of typifying pedon of Jangho series were investigated and physico-chemical properties were analyzed according to Soil Survey Laboratory Methods Manual. The typifying pedon of Jangho series has very dark grayish brown (10YR 3/2) gravelly silt loam A horizon (0~14 cm), very dark brown (7.5YR 3/2) silty clay BAt horizon (14~31 cm), dark brown (7.5YR 3/4) silty clay Bt1 horizon (31~58 cm), brown (7.5YR 4/4) silty clay Bt2 horizon (58~90 cm), and brown (7.5YR 4/4) clay Bt3 (90~120 cm) horizon. That is developed on river terraces. The typifying pedon has an argillic horizon from a depth of 14 to more than 120 cm and a base saturation (sum of cations) of less than 35% at 125 cm below the upper boundary of the argillic horizon. That can be classified as Ultisol. The typifying pedon has 0.9 % or more organic carbon in the upper 15 cm of the argillic horizon, and can be classified as Humult, which is reported for the first time in Korea. That does not have fragipan, kandic horizon, sombric horizon, plinthite, etc. in the given depths, and keys out as Haplohumult. Also that meets the requirements of Typic Haplohumult. That has 35 % or more clay at the particle-size control section, and has mesic soil temperature regime. Jangho series can be classified as fine, mixed, mesic family of Typic Haplohumults, not as fine silty over clayey, mixed, mesic family of Mollic Hapludalfs.

Improved Receding Horizon Fourier Analysis for Quasi-periodic Signals

  • Kwon, Bo-Kyu;Han, Soohee;Han, Sekyung
    • Journal of Electrical Engineering and Technology
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    • v.12 no.1
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    • pp.378-384
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    • 2017
  • In this paper, an efficient short-time Fourier analysis method for the quasi-periodic signals is proposed via an optimal fixed-lag finite impulse response (FIR) smoother approach using a receding horizon scheme. In order to deal with time-varying Fourier coefficients (FCs) of quasi-periodic signals, a state space model including FCs as state variables is augmented with the variants of FCs. Through an optimal fixed-lag FIR smoother, FCs and their increments are estimated simultaneously and combined to produce final estimates. A lag size of the optimal fixed-lag FIR smoother is chosen to minimize the estimation error. Since the proposed estimation scheme carries out the correction process with the estimated variants of FCs, it is highly probable that the smaller estimation error is achieved compared with existing approaches not making use of such a process. It is shown through numerical simulation that the proposed scheme has better tracking ability for estimating time-varying FCs compared with existing ones.