• Journal of Institute of Control, Robotics and Systems
• /
• v.15 no.1
• /
• pp.67-71
• /
• 2009

This paper presents a rank-constrained linear matrix inequality (LMI) approach to the design of a multi-objective controller such as $H_2/H_{\infty}$ control. Multi-objective control is formulated as an LMI optimization problem with a nonconvex rank condition, which is imposed on the controller gain matirx not Lyapunov matrices. With this rank-constrained formulation, we can expect to reduce conservatism because we can use separate Lyapunov matrices for different control objectives. An iterative penalty method is applied to solve this rank-constrained LMI optimization problem. Numerical experiments are performed to illustrate the proposed method.

• Proceedings of the KIEE Conference
• /
• 1997.07b
• /
• pp.446-448
• /
• 1997

The aim of this paper is to introduce a method designing the optimal model following boiler-turbine control system using genetic algorithms. This boiler-turbine control system is designed by applying genetic algorithms with reference model to the optimal determination of weighting matrices Q, R that are given by LQ regulator problem. These weighting matrices are optimized simultaneously in the search domain selected adequately. The effectiveness of this boiler-turbine control system is verified by computer simulation.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.12
• /
• pp.993-1000
• /
• 2001

Configuration-dependent nonlinear coefficient matrices in the dynamic equation of robot manipulator impose computa- tional burden in real-time implementation of tracking control based on the inverse dynamics controller. However, parallel manipulators such as Stewart platform have relatively small workspace compared to serial manipulators. Based on the characteristics of small motion range. nonlinear coefficient matrices can be approxiamted to constant ones. The modeling errors caused by such approximation are compensated for by H-infinity controller that treats the modeling errors disturbance. The proposed inverse dynamics controller with approximate dynamics combined with H-infinity control shows good tracking performance even for fast tracking control in which computation of full inverse dynamics is not easy to implement.

• The Korean Journal of Applied Statistics
• /
• v.4 no.1
• /
• pp.1-11
• /
• 1991

It is of great interest to consider the homogeniety of covariance matrices in MANOVA of discriminant analysis. If we lock at the problem of testing hypothesis, H : $\Sigma_1 = \Sigma_2$ from an invariance point of view where $\Sigma_i$ are the covariance matrix of two independent p-variate distribution, the testing problem is invariant under the group of nonsingular transformations and the hypothesis becomes H : $\delta_1 = \delta_2 = \cdots = \delta_p = 1$ where $\delta = (\delta_1, \delta_2, \cdots, \delta_p)$ is a vector of latent roots of $\Sigma$. Bias-corrected estimators of eigenvalues and sampling distribution of the test statistics proposed are obtained. Pooled-bootstrap method also considered for Bartlett's modified likelihood ratio statistics.

• Communications of the Korean Mathematical Society
• /
• v.15 no.3
• /
• pp.533-540
• /
• 2000

In the present paper, we study a non-degenrate ruled surface along a null curve in a 3-dimensional Minkowski space E31, which is called a null scroll, an investigate some characterizations of null scrolls satisfying the condition H=AH, A Mat(3, ), where denotes the Laplacian of the surface with respect to the induced metric, H the mean curvature vector and Mat(3, ) the set of 3$\times$3-real matrices.

• The Korean Journal of Malacology
• /
• v.3 no.1
• /
• pp.3-14
• /
• 1987

The electrophoretic and innunological cnalyses of organic matrices in the shells of freshwater bivalves were made in order to dlucidate the biochemical characteristics and species-specific differinces of the applied shells, The water-soluble and insoluble matrices of four species of freshwater bivalves, Andodonta fukudai, Unio douglasiae, Lanceolaria and Chrbicula fluminea, were used as analytical materials, There was non-identity in immuno affinity between anti soluble matrix(anti-Sm) and anti insoluble matrix(anti-ISM)sera against the organic matrix of Andodnta fukudai. The SMs of four species (S. fukudai, U.douglasiae, L. acrorhyncha, and C. fluminea) showed the differences in the precipitate arcs at the level of family, though ISMs did mot show differences. In the electrophoretic analysis, all foru species had two SDS-electrophoretic bands of SM, of which molecular wights appeared to be lower than 55,000, shereas the native organic matrices of foru speceis had higher molecular weighrs than those from SDS-dldctrophoresis. Only calcium ion among many ions in extrapallial fluid(EPF) caused SM to change into insoluble molecules, thus the EPF pretreated with Ca++did not form the precipitate arc when did the immuno diffusion whth anti SM serum. ISM precursor may be polymerized into macromolecules like periostracin, a precusor of periostracum, judging from the similat polymerization patterns in 0.1M Tris formate buffer(pH 3); they may be made insoluble macromolecules due to their strong natrue of hydrophobicity.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.7
• /
• pp.1-8
• /
• 2008

Low Density Parity Check codes(LDPC) are recently focused on communication systems due to its good performance. The standard of WiBro has also included LDPC codes as a channel coding. The weak point of implementation for LDPC encoder is that conventional binary Matrix Vector Multiplier has many clock cycles which limit throughput. In this paper, we propose semi-parallel architecture by using cyclic shift registers and exclusive-OR without conventional Matrix Vector Multipliers over the standard parity check matrices with Circulant Permutation Matrices(CPM). Furthermore, multi-rate encoder is designed by using proposed architecture. Our encoder with multi-rate for IEEE 802.16e LDPC has lower clock cycles and higher throughput.

• Archives of Pharmacal Research
• /
• v.26 no.8
• /
• pp.644-648
• /
• 2003

To investigate the feasibility of developing a new ondansetron transdermal system, the effects of vehicles and penetration enhancers on the in vitro permeation of ondansetron hydrochloride (OS) from a pressure-sensitive adhesive (PSA) matrices across dorsal hairless mouse skin were studied. Vehicles employed in this study consisted of various ratios of propylene glycol monocaprylate (PGMC)-diethylene glycol monoethyl ether (DGME) co-solvents and PGMC-propylene glycol (PG) co-solvents with 3% oleic acid. $Duro-Tak^\circledR$ 87-2100 and $Duro-Tak^\circledR$ 87-2196 were used as PSAs. The concentration of DGME in PGMC-DGME co-solvent system affected the release rate; as the concentration of DGME increased, the release rate decreased. The cumulative release amount of OS increased as the ratio of PSA to drug solution decreased. The permeation flux was also primarily affected by the amount of PSAs; as the amount decreased, the permeation flux increased. The overall fluxes from matrix formulations were significantly lower when compared to those obtained from solution formulations. The ratio of PG to PGMC did not affect permeation flux, while the lag time decreased significantly from $5.14\pm3.31 to 0.31\pm0.12$ h as the PG increased from 40% to 60%.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.43 no.7 s.349
• /
• pp.50-57
• /
• 2006

Low-density parity-check (LDPC) codes are recently emerged due to its excellent performance. However, the parity check (H) matrices of the previous works are not adequate for hardware implementation of encoders or decoders. This paper proposes a hybrid parity check matrix which is efficient in hardware implementation of both decoders and encoders. The hybrid H-matrices are constructed so that both the semi-random technique and the partly parallel structure can be applied to design encoders and decoders. Using the proposed methods, the implementation of encoders can become practical while keeping the hardware complexity of the partly parallel decoder structures. An encoder and a decoder are designed using Verilog-HDL and compared with the previous results.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.560-564
• /
• 1996

A mixed H$^{2}$/$H^{\infty}$ controller design method for linear systems with time delay in all variables and parameter uncertainties in all system matrices is proposed. Robust $H^{\infty}$ performance and H$^{2}$ performance condition that accounts for model-matching of closed loop system and disturbance rejection is also derived. With expressing uncertain system with linear fractional transformation form, we transform the robust stability and performance problem to the H$^{2}$/$H^{\infty}$ optimization problem and design a mixed H$^{2}$/$H^{\infty}$ controller. Using the proposed method, mixed H$^{2}$/$H^{\infty}$ controller for underwater vehicle with time delay and parameter variations are designed. Simulations of a design example with hydrodynamic parameter variations and disturbance are presented to demonstrate the achievement of good robust performance.t performance.ance.