• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
• /
• pp.687-692
• /
• 1991

To reduce the complexity in constructing a fuzzy logic controller of multivariable systems, three major methods are presented. One is the method of constructing single-input-single-output fuzzy logic controllers after decoupling the target system. Another is the method of using fuzzy relation matrices which indicate the relation between each input and output. The other is the method of using the hierarchically classified inputs which dominantly influence one output than other inputs. Using the last two methods, simulation results of fuzzy logic controller implemented on 160MW boiler-turbine plant model are also shown.

• 한국정밀공학회지
• /
• 제11권5호
• /
• pp.66-74
• /
• 1994

A loop-shaping LQ controller is synthesized for tandem cold mills. And a new loop- shaping technique is suggested for LQ controller design. The suggested loop-shaping LQ control system is compared with the standard loop-shaping LQ control system. The simulation results show that the theickness and interstand tension control accuracy of tandem cold mills can be improved by the compensated loop-shaping LQ controller.

• 대한수학회논문집
• /
• 제38권2호
• /
• pp.509-524
• /
• 2023

In this study, we characterize the structure of the multivariable mappings which are sextic in each component. Indeed, we unify the general system of multi-sextic functional equations defining a multi-sextic mapping to a single equation. We also establish the Hyers-Ulam and Găvruţa stability of multi-sextic mappings by a fixed point theorem in non-Archimedean normed spaces. Moreover, we generalize some known stability results in the setting of quasi-𝛽-normed spaces. Using a characterization result, we indicate an example for the case that a multi-sextic mapping is non-stable.

• Acute and Critical Care
• /
• 제33권4호
• /
• pp.230-237
• /
• 2018

Background: Socioeconomic status (SES) is closely associated with health outcomes, including mortality in critically ill patients admitted to intensive care unit (ICU). However, research regarding this issue is lacking, especially in countries where the National Health Insurance System is mainly responsible for health care. This study aimed to investigate how the SES of ICU patients in South Korea is associated with mortality. Methods: This was a retrospective observational study of adult patients aged ${\geq}20$ years admitted to ICU. Associations between SES-related factors recorded at the time of ICU admission and 30-day and 1-year mortalities were analyzed using univariable and multivariable Cox regression analyses. Results: A total of 6,008 patients were included. Of these, 394 (6.6%) died within 30 days of ICU admission, and 1,125 (18.7%) died within 1 year. Multivariable Cox regression analysis found no significant associations between 30-day mortality after ICU admission and SES factors (P>0.05). However, occupation was significantly associated with 1-year mortality after ICU admission. Conclusions: Our study shows that 30-day mortality after ICU admission is not associated with SES in the National Health Insurance coverage setting. However, occupation was associated with 1-year mortality after ICU admission.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1994년도 추계학술대회 논문집
• /
• pp.449-454
• /
• 1994

The Stewart Platform is one example of a motion simulator which generater 6DOF motion in space by six actuators in parallel. The presented control methrol of 6DOF motion simulator is generally classified into two types, one is SISO and the other is MIMO control type. The SISO control can't compensate for external load variation and different dynamic behavior of 6DOF motion, trerefore this type don's control motion precisely. On the other hand, the MIMO control compensates for a interference of 6DOF motion because MIMO controller is designed with 6DOF motion simulator synamics. But MIMO control of motion simulator has a complexity of 6DOF displacement feedback, because in oder to obtain feedback value we must solve the forward kinematics using measurement of cylinder length or design a state estimator, unless measurement of 6DOF displacement is possible. In this paper, a multivariable controller using H .inf. optimal control theory is designed to consider a interference of 6DOF motion and to obtain robust,precise control of system. Also in order to solve the mentioned problem of MIMO control, this paper presents a modified MIMO control model which control 6DOF motion by using feedback of measurement od cylinder length.

• 대한전기학회논문지
• /
• 제36권7호
• /
• pp.501-513
• /
• 1987

다변수 비선형시스텝의 각 출력을 독립적으로 제어하기 위한 방식에는 decoupling과 decomposition 두가지 방식이 있는데 기존 연구에서는 이 두 개념의 구별이 분명하지 않다. 본 논문에서는 보다 실용적인 decomposition 방식에 대한 여러 분제들을 고찰한다. decoupling과 decomposition 의 근본적 차이점을 분명히 하고 새 연구결과로서 decomposition 을 통하여 각 출력의 독립제어를 가능하게 하는 비선형 되먹임 제어법칙들을 모두 찾아낸다. 이들 비선형 되먹임 제어법칙들은 특수구조를 갖는 `표준분해시스템`을 통하여 간단하게 표시되어 질 수 있다. 본 연구의 중요성을 강조하기 위하여 한 간단한 예를 든다.

• 동력기계공학회지
• /
• 제15권1호
• /
• pp.78-85
• /
• 2011

In order to design the control system of the magnetic bearing for the high speed 3 phase induction motor, the mathematical modeling was conducted and LQ regulator system was designed. When the plant is controllable and detectable, the nominal stability of LQ regulator could be guaranteed. However, LQ regulator doesn't ensure the robustness of stability and performance for the real system because LQ control is the mathematical optimal theory. In this paper to ensure the robustness of stability and performance for the real system, the control systems are designed by the simulation to the variation system parameters and this method was confirmed as an effective means.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 D
• /
• pp.2249-2251
• /
• 2001

This paper proposes that it minimizes interference between link at high speed trajectory tracking of 2-degree parallel link manipulator and QFT(Quantitative Feedback Theory) controller which robust structure uncertainty and disturbance of plant. And using ICD(Individual Channel Design), it separates two channel from multivariable system, parallel link manipulator and designs robust controller with applying MISO QFT to each channel. Finally, we make sure of robustness and excellence of QFT controller through simulation and experiment.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.150-150
• /
• 2000

We as modal parameter estimation technique by developing a residual based system reconstruction and using the system matrix coordinate transformation. The modal parameters can be estimated from and residues of the system transfer functions expressed in modal coordinate basis, derived from the state space system matrices. However, for modal parameter estimation of multivariable and order structural systems over broad frequency bands, this non-iterative algorithm gives high accuracy in the natural fre- and damping ratios. From vibration tests on cross-ply and angle-ply composite laminates, the natural frequencies and damping ratios on be estimated using tile coordinates of the structural system reconstructed fro the experimental frequency response. These results are compared with those of finite element analysis and single-degree-of-freedom curve-fitting.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
• /
• pp.209-212
• /
• 1990

The activated sludge process is a commonly used method for treating sewage and waste waters. The process is characterized by a lack of measurement instrumentations and control goals that are neither well defined nor well understood. In the present study the concept of fuzzy control is employed for such process in which a design method for fuzzy controller based on a multivariable fuzzy reasoning algorithms is investigated and then simulation results are presented.