In the butt-joint couPling using cylindrical ferrules and sleeve, the insertion loss of the single-mode optical connector depends on the accuracies of components that consist of optical connector (i.e., sleeve, ferrul...
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In the butt-joint couPling using cylindrical ferrules and sleeve, the insertion loss of the single-mode optical connector depends on the accuracies of components that consist of optical connector (i.e., sleeve, ferrule, fiber, etc.). It is also difficult to achieve both cost reduction and performance improvement simultaneously in optical connectors because higher accuracies give better performance but cause higher cost. For single-mode fiber connection, the dimensional accuracies of currently available ferrules and optical fibers are not sufficiently high to ensure a low insertion loss with reasonable cost. Many efforts have been made to have low insertion loss without any higher order of accuracies of components. In one of the proposed methods the technique of stepwise orientation of the ferrule is used to reduce the transverse offset between butt-joint fiber cores by achieving the minimizing loss region (MLR). This method requires several stepwise rotations to make the fiber core within the MLR, which was determined by the optimal trade-off between insertion loss and working dme. In this method the insertion loss severely depends on the size of the predetermined MLR. In this paper, a new assembling method through which a very small MLR can be achieved in a short time, is proposed.
In this note, we present a robust version of the adaptive control algorithm established by Kreisselmeier [1]. We know that if the conventional dead-zone adaptive law is used in the adaptive system, it is troubleseome ...
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In this note, we present a robust version of the adaptive control algorithm established by Kreisselmeier [1]. We know that if the conventional dead-zone adaptive law is used in the adaptive system, it is troubleseome that the size of the unmodeled dynamics, denoted by epsilon, must be within the chosen dead-zone size for robustness. In this robust version, by introducing a positive design parameter epsilonBAR, the robust stability can be achieved without this constraint. It is also shown that the plant output and control input will converge asymptotically within a bound proportional to max {cepsilon, epsilonBAR} := epsilon(m), where c is a finite positive constant. Moreover, in the ideal case (i.e., epsilon = 0), the plant output and control input will converge to zero under some condition.
Adaptive identification and control algorithms can exhibit local instability when certain ideal assumptions, such as satisfaction of SPR conditions, are violated. However, recent conjectures suggest that due to a '...
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Adaptive identification and control algorithms can exhibit local instability when certain ideal assumptions, such as satisfaction of SPR conditions, are violated. However, recent conjectures suggest that due to a ''self-stabilization'' mechanism, global boundedness may still hold despite local instabilities. We present counterexamples to these conjectures, showing that self stabilization is bypassed via ''hidden'' unbounded parameter drift. Although parameter drift instability is known to occur in adaptive systems with disturbances, concrete examples are given to show that unbounded drift can also occur in the disturbance-free case when SPR conditions are violated.
In this paper, computer algorithms are developed for determining optimal purchasing strategies for firms that receive extended payment terms from vendors. The resultant models are particularly attractive in high-volum...
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In this paper, computer algorithms are developed for determining optimal purchasing strategies for firms that receive extended payment terms from vendors. The resultant models are particularly attractive in high-volume environments with extended payment terms, a high opportunity cost of capital, and relatively large inventory-related costs. It is shown that purchases of quantities smaller than the traditional Economic Order Quantity may be appropriate in these environments and other situations where vendors offer either all-units or incremental purchase price discounts. The resultant algorithms are solved in this study using a spreadsheet-based search procedure implemented on a personal computer.
Work has been underway at the CSM on the development of autonomous (tele-managed) LHD mining machines. Previous work has shown that ultrasonic sensors exhibit several characteristics which make them a reasonable choic...
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Work has been underway at the CSM on the development of autonomous (tele-managed) LHD mining machines. Previous work has shown that ultrasonic sensors exhibit several characteristics which make them a reasonable choice for sensor based navigation in underground mining operations. This paper discusses recent work done to (1) develop control algorithms for use with these sensors, (2) experiments with a scale model of an LHD to verify the ultrasonic based control and modeling methods, and (3) approaches to developing real-time task level control models.
In this short note, adaptive and nonadaptive control algorithms, which make use of fundamental mathematical property concerning positive definite matrices and Lyapunov stability theory are proposed for the control of ...
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In this short note, adaptive and nonadaptive control algorithms, which make use of fundamental mathematical property concerning positive definite matrices and Lyapunov stability theory are proposed for the control of robot manipulators. Using the fact that matrix dD(q)/dt - 2C(q,q) is skew symmetric, nonadaptive controllers which have a simplified structure with less computational burden are proposed. Then based on the dynamic equations of robot manipulators, parameter adaptation rules are developed for updating the partially or totally unknown parameters in the proposed nonadaptive controllers, generalizing the nonadaptive controllers to model reference adaptive controllers. To further take the advantage of the simplified structure of the proposed adaptive controllers, the dynamic model of robot manipulators must be expressed linearly in terms of the parameters of links and payload inertias. So we also present a method on how to derive the dynamic model of robot manipulator which is linear in terms of its parameters. This dynamic model of robot manipulators is also suitable for the pure identification of the parameters of links and payload of the manipulator.
A comprehensive analysis of reported hepatitis C virus genomic sequences comprising 151 partial or complete nucleotide sequences and 159 partial or complete amino acid sequences revealed an irregular composition of co...
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A comprehensive analysis of reported hepatitis C virus genomic sequences comprising 151 partial or complete nucleotide sequences and 159 partial or complete amino acid sequences revealed an irregular composition of conserved and variable regions. There were but eight conserved nucleotide sequences, none outside the 5' noncoding and structural regions. A search among conserved amino acid sequences revealed 14 candidate B-cell epitopes, which were chosen mainly on the basis of their hydrophilicity profiles. Twenty five candidate T-cell epitopes were selected according to the criteria of absolute conservation of amino acid sequence, together with characteristic sequence motifs, amphipathic helical structure, or both. Conserved peptide sequences, with the characteristics of both B- and T-cell epitopes, were identified in the nonstructural 5 (NS5) region of the genome.
An important, yet seemingly unattainable, goal in structural molecular biology is to be able to predict the native three-dimensional structure of a protein entirely from its amino acid sequence. Prediction methods bas...
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An important, yet seemingly unattainable, goal in structural molecular biology is to be able to predict the native three-dimensional structure of a protein entirely from its amino acid sequence. Prediction methods based on rigorous energy calculations have not yet been successful, and best results have been obtained from homology modelling and statistical secondary structure prediction. Homology modelling is limited to cases where significant sequence similarity is shared between a protein of known structure and the unknown. Secondary structure prediction methods are not only unreliable, but also do not offer any obvious route to the full tertiary structure. Recently, methods have been developed whereby entire protein folds are recognized from sequence, even where little or no sequence similarity is shared between the proteins under consideration. In this paper we review the current methods, including our own, and in particular offer a historical background to their development. In addition, we also discuss the future of these methods and outline the developments under investigation in our laboratory.
This paper presents a new method of keeping one of the most suitable driving conditions for regulating the outflow volume from the ventricular-assist device (VAD). The experimental results from a mock circulatory syst...
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This paper presents a new method of keeping one of the most suitable driving conditions for regulating the outflow volume from the ventricular-assist device (VAD). The experimental results from a mock circulatory system have shown that the relationship between the stroke volume and the systolic duration of the VAD can be specified by the combination of characteristic curves of the positive and negative drive pressures. The optimal operating point on the characteristic curve have been defined as the point at which thrombosis on the blood-contacting surface and hemolysis due to mechanical damage can be avoided and at which the driving energy can be minimized. The present analysis has been revealed that the optimal operating point is the vertex of the triangular figure obtained from the characteristic curve. The algorithms for keeping the optimal operating point and for regulating the stroke volume have been also proposed.
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