• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.2
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• pp.164-170
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• 2005

The amounts and nutrient compositions in precipitation, throughfall, stemflow and soil solution of natural deciduous forests (Quercus variabilis and Q. mongolica) were examined in Gwangju, Gyeonggi Province. The proportion to gross precipitation was $85\%$ for throughfall, $2-6\%$ for stem flow, $53-54\%$ for Ao horizon soil solution, $23-30\%$ for A horizon soil solution, and $11-14\%$$ for B horizon soil solution, respectively. pH and K concentration increased in throughfall and only K concentration increased in stemflow. Canopy leaching appeared to influence these changes. pH, and Ca and Mg concentrations increased significantly in the Ao horizon soil solution, and Ca concentration was higher in the B horizon than in the A horizon. However, there were no significant differences in pH and other nutrient concentrations between A and B horizons. Litter decomposition and leaching from Ao horizon might explain the changes. K, Mg and Cl concentrations in throughfall and soil solution decreased with precipitation. Nutrient contents increased in the transports from precipitation, through throughfall, to Ao horizon soil solution, while they decreased in the transport from A to B horizon soil solution. Stemflow contained less than $10\%$ of total (throughfall plus stemflow) nutrient contents.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.52.1-52
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• 2002

Young Sam Lee : He is currently a PhD candidate student. His research interest includes time-delay systems, signal processing, and receding horizon control. Wook Hyun Kwon : His research interest includes time-delay systems, signal processing, receding horizon control, and robust control. He is the president of IFAC 2008 which is to be held in Korea. Soo Hee Han : He is currently a PhD candidate student. His research interest includes time-delay systems, signal processing, receding horizon control, and communication.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1896-1900
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• 2003

In this paper, a new type of output feedback control, called a receding horizon finite memory control (RHFMC), is proposed for stochastic discrete-time state space systems. Constraints such as linearity and finite memory structure with respect to an input and an output, and unbiasedness from the optimal state feedback control are required in advance. The proposed RHFMC is chosen to minimize an optimal criterion with these constraints. The RHFMC is obtained in an explicit closed form using the output and input information on the recent time interval. It is shown that the RHFMC consists of a receding horizon control and an FIR filter. The stability of the RHFMC is investigated for stochastic systems.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1055-1059
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• 1990

This paper proposed a predictive tracking controller for the continuous-time systems by using the receding horizon concept in the optimal tracking control. This controller is the continuous-time version of the previous RHTC (Receding Horizon Tracking Control) for the discrete-time state space models. The problems in implementing the feedforward part of this controller is discussed and a approximate method of implementing this controller is presented. This approximate method utilizes the information of the command signals on the receding horizon and has simple constant feedback and feedforward gain. To perform the offset free control, the integral action is included in the continuous time RHTC. By simulation it is shown that the proposed method gives better performance than the conventional steady state tracking control.

• International Journal of Reliability and Applications
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• v.10 no.1
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• pp.33-42
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• 2009

In most of literatures of age replacement policy, the authors consider the case that a new item starts operating at time zero and is to be replaced by new one at time T. It is, however, often to purchase used items because of the limited budget. In this paper, we consider age replacement policy of a used item whose age is $t_0$. The mathematical formulas of the expected cost rate per unit time are derived for both infinite-horizon case and finite-horizon case. For each case, we show that the optimal replacement age exists and is finite and investigate the effect of the age of the used item.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.3
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• pp.235-244
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• 2014

This article introduces recent trends in RHC (Receding Horizon Control), also known as MPC (Model Predictive Control), that has been well recognized in industry and academy as a systematic approach for optimal design and constraint management. Constrained and robust RHCs will be briefly reviewed with milestone results. Among the diverse developments and achievements of RHCs, implementation issues will be focused on, together with the latest applications. In particular, this article introduces results on how to solve a finite horizon open-loop optimal control problem in an efficient way, together with code generation for real-time execution and easy implementation. Instead of traditional applications such as refineries and petrochemical plants, this article highlights some selected emerging applications, such as energy management systems and mechatronics, that have resulted from state-of-the-art high performance computing power and advanced numerical schemes.

• Proceedings of the KIEE Conference
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• 1979.08a
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• pp.80-82
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• 1979

While the standard linear-quadratic-Gaussian problem has fixed horizons, this paper considers the LQG problem with moving horizons. By the separation principle the solution will be given by the kalman filter with the approaching horizon and the LQ regulator with the receding horizon. Sufficient conditions on weighting matrices are derived under which the filter and regulator are asymptotically stable. It wall be shown that the computation method of the moving-horizon LQG regulators is better than that of the standard LQG regulator. The performance measure between the two optimal controls will be compared. A simulation result is given in order to show the usefulness of the moving-horizon LQG regulator.s

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4902-4909
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• 2012

In this paper, the TOU tariff's based building indoor temperature control algorithm in cooling systems is proposed using control horizon method. A control horizon switching method and linear programming algorithm is used for optimal control, and both TOU and peak tariffs are included to calculate the energy costs. Simulation results show that the reductions of energy cost and peak power can be obtained using proposed algorithms.

• The Journal of Industrial Distribution & Business
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• v.9 no.10
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• pp.83-89
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• 2018

Purpose - The purpose of this study examines when the optimism impact on financial asset price forecasting and the boundary condition of optimism in the financial asset price forecasting. People generally tend to optimistically forecast their future. Optimism is a nature of human beings and optimistic forecasting observed in daily life. But is it always observed in financial asset price forecasting? In this study, two factors were focused on considering whether the optimism that people have applied to predicting future performance of financial investment products (e.g., mutual fund). First, this study examined whether the degree of optimism varied depending on the direction of the prior price trend. Second, this study examined whether the degree of optimism varied according to the forecast period by dividing the future forecasted by people into three time horizon based on forecast period. Research design, data, and methodology - 2 (prior price trend: rising-up trend vs falling-down trend) × 3 (forecast time horizon: short term vs medium term vs long term) experimental design was used. Prior price trend was used between subject and forecast time horizon was used within subject design. 169 undergraduate students participated in the experiment. χ² analysis was used. In this study, prior price trend divided into two types: rising-up trend versus falling-down trend. Forecast time horizon divided into three types: short term (after one month), medium term (after one year), and long term (after five years). Results - Optimistic price forecasting and boundary condition was found. Participants who were exposed to falling-down trend did not make optimistic predictions in the short term, but over time they tended to be more optimistic about the future in the medium term and long term. However, participants who were exposed to rising-up trend were over-optimistic in the short term, but over time, less optimistic in the medium and long term. Optimistic price forecasting was found when participants forecasted in the long term. Exposure to prior price trends (rising-up trend vs falling-down trend) was a boundary condition of optimistic price forecasting. Conclusions - The results indicated that individuals were more likely to be impacted by prior price tends in the short term time horizon, while being optimistic in the long term time horizon.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.3
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• pp.260-264
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• 1985

Ferrallitique soils are real tropical soils, with an oxic B horizon such a horizon is at least 30cm thick, has > 15% clay, diffuse horizon boundaries, no weatherable minerals and a CEC of clay < 16 me per 100g. These soils are in general the real reddish or yellowish very uniform tropical clay soils with an orchric A horizon and a deep B horizon, otherwise almost characterless. The soil profile looks uniform and maybe some metres thick. It is well drained, has a good permeability and a stable structure. As there is little or no weatherable mineral, because these soils are old and exhausted of bares, natural fertility is very low. There has been a complicated process of soil formation. Intensive and continuous weathering over a very long period has resulted in leaching of bases and silica, in relative accumulation of resquioxides and in formation of kaolinitic clay. Until recently, there has been much confusion in classifing and naming tropical soils. Particularily what are now Ferralsols in the FAO scheme, and Oxisols in Soil Taxonomy. Old names of various classification system are: Lateritic soils, Latosols, Ferrallitic soils. For agriculture, these soils are important, but chemically very poor, not only because of a low CEC but also because of deficiency of bases, especially Ca, Mg, and K, strong P fixation and high exchangeable Al percentage.