SUMMARYThis paper proposes an identification algorithm for time-varying systems. We apply subspace method for estimation, since it is known to be useful when the input-output (I/O) data are observed by multi-input multi-output (MIMO) systems. Among many proposed techniques of subspace methods, we use MOESP (MIMO Output-Error State Space model identification) in this paper, which assures arithmetic stability by RQ factorization and singular value decomposition (SVD). Generally, subspace methods can be applied after I/O data collection, so that we introduce updated steps of matrices for PI-MOESP, which uses past inputs for instrumental variables. We propose a recursive update algorithm of PI-MOESP, including estimation step of the system order, and consider some parameters inherent to the algorithm, namely, initial number of data, estimation step of the order, and forgetting factor. A numerical example shows the usefulness of the proposed method.
In identification of linear discrete timeinvariant systems, there are some systems whose parameters are difficult to be estimated by least square method (LS) under the condition that unbiased consistent estimators are given. The problem of parameter estimation by LS reduces to numerical analysis of simultaneous linear equation. In this paper, it is shown that these systems have large condition number of data matrix which is the coefficient matrix of the simultaneous linear equation to be solved. Further, in these systems, it is pointed out that the estimated parameters by recursive least square method (RLS) converge to the true values of system parameters, but numerical unstable phenomena often appear in RLS algorithm.
In general, most of koreans usually have used Hangul and MS-word as a Word Processor. We studied about the functional efficiency by comparing and analyzing Text Mode, Equation Mode, Table Mode, Frame Editor & OLE Mode, Chart Mode and the other Modes to evaluate the common utility used Hangul 97 and MS-word 97 as a Word Processor. As a result, File size, Drag & Drop, Compression and storage etc. have been recognized characters remarkably in each case. We studied about Hangul 97, MS-word 97 as a user for evaluation criteria items . As a matter of fact, we used Tool Book and Director. So, we designed, developed and materialized S/W "garbage generation, separation, and collection" and then we also compared and examined those Text Mode, Sound Mode, Summation Algorithm Mode and Moving image Mode. In consequence, a user's point of view, characters of Tool Book and Director are showed remarkably through the findings of the questionnaire.
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