725 research outputs found
A direct computation of state deadbeat feedback gains
A method for computing a feedback gain that achieves state deadbeat control is given. From systems given in the staircase form, this method derives the deadbeat gain in a numerically reliable way. It is shown that the gain turns out to be LQ optimal for some weightings
A construction of multivariable MRACS with fixed compensator using coprime factorization approach
A multivariable model reference adaptive control system (MRACS) with a fixed compensator is proposed. First, a new two-degree-of-freedom (2DOF) compensator with disturbance estimator is derived. Using this structure, a multivariable MRACS with fixed compensator is constructed. Since the proposed method is based on the 2 DOF structure, the fixed compensator is chosen independently of specifications for reference commands. The boundedness of all signals in the closed-loop system and the convergence of the output error are proved. A design method of the fixed compensator for MRACS with low sensitivity is also given. Finally, numerical examples are illustrated in order to show the effectiveness of the proposed method </p
Parametrization of identity interactors and the discrete-time all-pass property
This paper gives a concise parametrization of all identity interactors of a discrete-time multivariable square system. This is performed by means of a state-space description computed from a given particular interactor of the system. The paper then proposes a selection of the parameter which leads to an all-pass closed-loop transfer matrix. This closed-loop system turns out to be equivalent to a certain LQ (linear quadratic) optimal feedback system. A numerical example is given to illustrate the results</p
A direct algorithm for state deadbeat control
The authors propose a novel method for computing state deadbeat feedback gains from systems given in the staircase form. The proposed method uses only manipulations of given matrices, and hence is more direct than the existing method, which requires orthogonal transformations repeatedly. It is shown that the obtained gain is linear quadratic optimal for some weighting matrices </p
A design method of multivariable model reference adaptive control system using coprime factorization approach
A design method for multivariable model reference adaptive control systems (MRACS) using a coprime factorization approach is proposed. First, a relation between the coprime factorization over RH∞ and the interactor matrix is derived. Using this relation, a method for design of multivariable MRACS over the ring of proper stable rational functions is obtained. Since the proposed method is based on the coprime factorization approach, the control structure in this paper is more simple. It is shown that the control structure of multivariable MRACS by other authors is included in the structure proposed in this paper. A robust MRAC scheme which achieves asymptotic rejection of unmeasurable disturbances is derived also </p
Growing Need for Diagnostic Precision in Rheumatoid Arthritis: Proposal of MR Imaging Criteria for Early Diagnosis
The recent and revolutionary paradigm shift involving novel therapeutics for the treatment of rheumatoid arthritis (RA) has called for changes in the early diagnosis of RA. Physicians now need to diagnose RA earlier, and with greater accuracy, in order to initiate effective definitive treatment as early as possible. However, due to the complexity and diverseness of RA, we still do not have comprehensive diagnostic criteria for RA readily available. To find a solution to this challenge, we aimed to develop practically useful criteria which integrate gadolinium (Gd) contrast-enhanced magnetic resonance imaging (MRI) findings with clinical manifestations of the disease. These diagnostic criteria we propose, the “diagnostic criteria for early RA with MRI findings,” are composed of two domains. The first domain consists of clinical findings suggestive of RA, which include both entry criteria—i.e., polyarthralgia of hands (joint pain of three or more joint areas confirmed by a physician), and exclusion criteria—i.e., exclusion of other rheumatic conditions including systemic lupus erythematosus (SLE), dermatomyositis and polymyositis (PM/DM), mixed connective tissue disease (MCTD), primary Sjögren’s syndrome (SS), and Behçet’s disease (BD). The second domain constitutes MRI criteria, which represent Gd-enhanced MRI findings indicating bilateral synovial enhancement seen in any joints of the proximal interphalangeal (PIP), metacarpophalangeal (MCP), or wrist joints. RA is defined by fulfilling all conditions of both domains. Our prospective study demonstrated that these criteria for the diagnosis of early RA, incorporating MRI findings with physical manifestations, can successfully distinguish patients with RA from those with other mimicking conditions, showing a sensitivity of 96%, specificity of 86%, and accuracy of 92%. When a case does not meet the criteria, RA can be ruled out with a high negative predictive value of 95%. We believe our “diagnostic criteria for early RA with MRI findings” can greatly help to solve unmet diagnostic needs in the early treatment of RA
釣藤散の循環調節に関する薬理学的研究
取得学位:博士(薬学),学位授与番号:博甲第393号,学位授与年月日:平成13年3月22日,学位授与年:200
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