• International Journal of Control, Automation, and Systems
• /
• 제2권4호
• /
• pp.475-484
• /
• 2004

In this paper, we present a dynamic output-feedback receding horizon $H_{\infty}$controller for linear discrete-time systems with disturbance. The controller is obtained numerically from the finite horizon output-feedback $H_{\infty}$optimization problem, which is, in fact, hardly solved analytically. Under a matrix inequality condition on the terminal weighting matrix, the monotonic decreasing property of the cost is shown. This property guarantees both the closed-loop stability and the $H_{\infty}$norm bound. Then, we extend the proposed design method to a reference tracking problem and a problem for time-varying systems. Numerical examples are given to illustrate the performance of the proposed controller.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2018년도 춘계학술대회
• /
• pp.119-121
• /
• 2018

Deepwater Horizon 사고 사례 분석을 통해 Kick 제어와 Blowout 및 인적요소 사이에 서로 관련성이 있음을 확인하였다. Deepwater Horizon 사례가 다른 시추선 사고에도 적용되는지 확인하기 위해 본 논문에서는 인적요소, Kick 제어 및 Blowout 사고와의 상관 관계에 대해 분석하였다. 분석에 사용된 사고사례는 Trident V 프로그램으로 분석된 1981년부터 2015년까지의 60건이며, 인적요소가 예측 불가한 Kick 발생 및 심각한 유정폭발에 어떠한 영향을 주는지 SPSS 프로그램을 통해서 분석하였다. 분석 결과 인적요소는 Kick의 제어에 더 많은 영향을 주는 것으로 판단되었고 이 결과를 토대로 향후 선급 및 국제표준기구의 관련 규정 개정 방안에 관해 제안하였다.

• Advances in robotics research
• /
• 제1권1호
• /
• pp.41-59
• /
• 2014

This paper deals with the problem of steering a group of mobile robots along a reference path while maintaining a desired geometric formation. To solve this problem, the overall formation is decomposed into numerous geometric patterns composed of pairs of robots, and the state of the geometric patterns is defined. A control algorithm for the problem is proposed based on the Nash equilibrium strategies incorporating receding horizon control (RHC), also known as model predictive control (MPC). Each robot calculates a control input over a finite prediction horizon and transmits this control input to its neighbor. Considering the motion of the other robots in the prediction horizon, each robot calculates the optimal control strategy to achieve its goals: tracking a reference path and maintaining a desired formation. The performance of the proposed algorithm is validated using numerical simulations.

• Imaging Science in Dentistry
• /
• 제51권4호
• /
• pp.461-466
• /
• 2021

Fibro-osseous lesions are a poorly defined category of conditions affecting the jaws and craniofacial bones, and include developmental lesions, reactive or dysplastic lesions, and neoplasms. Fibrous dysplasia and ossifying fibroma are the 2 main types of fibro-osseous lesions affecting the jaw, and ossifying fibroma is a true benign neoplasm of the bone-forming tissues with several well-recognized variants ranging from innocuous to extensively aggressive lesions. However, multiple simultaneous fibro-osseous lesions of the jaw bones involving all quadrants are exceedingly rare. One such case diagnosed by conventional radiography and computed tomography is discussed here.

• 산경연구논집
• /
• 제9권10호
• /
• pp.83-89
• /
• 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.

• 한국초지조사료학회지
• /
• 제23권1호
• /
• pp.65-70
• /
• 2003

본 시험은 알팔파 Vernal(대조품종), Anchor, P5444, DK120, DK125, Horizon, DK135, 루나및 기타와카바 9품종을 축산기술연구소 대관령지소(표고 800m)와 남원지소(표고 450m)에서각각 난괴법 3반복으로 수행하였다. 알팔파의 엽폭은 Vernal을 제외하고 모든 품종이 대형이었으며 개화기는 DK125가 가장 빨랐다. 초고는 Luna품종이 가장 컸으며 내한성은 P5444가 80.2%로 가장 높았다. 알팔파의 건물수량은 대관령에서 대조품종인 Vernal보다 많은 품종은 Luna가 4,200kg으로 공시된 품종 중 가장 높았다. 또한 남원에서는 대조품종인 Vernal 품종보다 공시된 품종 모두가 높았으나 P5444가 ha당 14,516kg으로 가장 높았다. 두 지역을 평균하였을 때 대조품종 Vernal의 7,517kg보다 공시된 다른 품종들이 모두 높았고 P5444품종이 9,171kg으로 가장 높았다. 대관령에서 알팔파 품종별 ADF 함량은 DK 120이 30.7%로 가장 낮았고 NDF 함량도 ADF 함량과 같은 경향을 보였다. 남원에서 알팔파 품종별 ADF 함량은 Horizon이 26%로 가장 낮았고 NDF 함량은 DK 125와 Horizon이 40.8%로 가장 낮았다. 조단백질 함량은 대관령에서는 P5444, Luna 및 DK 120이 높았으며, 또한 남원에서는 Horizon이 28.1%로 가장 높았다. 조단백질 함량을 조단백질 생산량으로 환산하였을 때 대관령 지역은 Luna가 915.6kg/ha으로 가장 높았으며, 남원지역은 Horizon이 3,787.3kg/ha으로 높았으나 두 지역 평균하여 P5444가 2,228.05kg/ha으로 가장 높았다. 이상의 결과를 요약하여 볼 때 생육특성, 건물수량과 사료가치 측면에서 현재 주로 재배하고 있는 Vernal보다 다른 품종들이 좋았으나 대관령에서는 Luna와 남원에서는 Horizon이, 양 지역에서는 P5444가 가장 유망한 품종이라고 생각된다.

• 전기의세계
• /
• 제49권9호
• /
• pp.4-8
• /
• 2000

Recently we have shown based on Lyapunov theorem that the closed loop system with the constrained infinite horizon H$\infty$ optimal controller is exponentially stable. moreover the on-line feedback implementation of the constrained infinite horizon H$\infty$ optimal control based on quadratic programs has been proposed. n this paper we summarize and discuss these results.

• International Journal of Control, Automation, and Systems
• /
• 제1권3호
• /
• pp.282-288
• /
• 2003

It is known that HIV (Human Immunodeficiency Virus) infection, which causes AIDS after some latent period, is a dynamic process that can be modeled mathematically. Effects of available anti-viral drugs, which prevent HIV from infecting healthy cells, can also be included in the model. In this paper we illustrate control theory can be applied to a model of HIV infection. In particular, the drug dose is regarded as control input and the goal is to excite an immune response so that the symptom of infected patient should not be developed into AIDS. Finite horizon optimal control is employed to obtain the optimal schedule of drug dose since the model is highly nonlinear and we want maximum performance for enhancing the immune response. From the simulation studies, we found that gradual reduction of drug dose is important for the optimality. We also demonstrate the obtained open-loop optimal control is vulnerable to parameter variation of the model and measurement noise. To overcome this difficulty, we finally present nonlinear receding horizon control to incorporate feedback in the drug treatment.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.1951-1956
• /
• 2003

It is known that HIV (Human Immunodeficiency Virus) infection, which causes AIDS after some latent period, is a dynamic process that can be modeled mathematically. Effects of available anti-viral drugs, which prevent HIV from infecting healthy cells, can also be included in the model. In this paper we illustrate control theory can be applied to a model of HIV infection. In particular, the drug dose is regarded as control input and the goal is to excite an immune response so that the symptom of infected patient should not be developed into AIDS. Finite horizon optimal control is employed to obtain the optimal schedule of drug dose since the model is highly nonlinear and we want maximum performance for enhancing the immune response. From the simulation studies, we find that gradual reduction of drug dose is important for the optimality. We also demonstrate the obtained open-loop optimal control is vulnerable to parameter variation of the model and measurement noise. To overcome this difficulty, we finally present nonlinear receding horizon control to incorporate feedback in the drug treatment.

• 천문학회보
• /
• 제42권2호
• /
• pp.55.1-55.1
• /
• 2017

HectoMAP is a dense redshift survey of red galaxies covering a 53 square degree strip of the northern sky, and Horizon Run 4 is one of the densest and largest cosmological simulations based on the standard Lambda cold dark matter model. We use HectoMAP and Horizon Run 4 to compare the physical properties of observed large-scale structures with simulated ones in the redshift range 0.22