• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.7
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• pp.103-109
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• 2016

Corrective control for asynchronous sequential machines is a novel automatic control theory that compensates illegal behavior or adverse effects of faults in the operation of existent asynchronous machines. In this paper, we propose a scheme of diagnosing and tolerating faults occurring to input channels of corrective control systems. The corrective controller can detect faults occurring in the input channel to the controlled machine, whereas those faults happening in the external input channel cannot be detected. The proposed scheme involves an outer operator which, upon receiving the state feedback, diagnoses a fault and sends an appropriate command signal to the controller for tolerating faults in the external input channel.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.139-147
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• 2014

We address the problem of corrective control for two asynchronous sequential machines in parallel connection. Each asynchronous machine receives the same external input and shows independent state transition characteristics. We propose a novel control scheme in which only one corrective controller is employed so as to make the closed-loop system of each machine match the behavior of the corresponding reference model. Compared with the former method utilizing two corrective controllers, our scheme can reduce the controller size and computational load in controller design. We present the existence condition and design procedure for a state-feedback corrective controller under the assumption that the controlled machines are of input/state type. The design procedure for the proposed controller is described in an illustrative example.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.5
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• pp.253-261
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• 2013

In this paper, we study the problem of controlling composite asynchronous sequential machines. The considered asynchronous machine consists of two input/state machines in cascade connection, where the output of the front machine is delivered to the input channel of the rear machine. The objective is to design a corrective controller realizing model matching such that the stable state behavior of the closed-loop system matches that of a reference model. Since the controller receives the state feedback of the rear machine only, there exists uncertainty about the present state of the front machine. We specify the existence condition for a corrective controller given the uncertainty. The design procedure for the proposed controller is described in a case study.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.4
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• pp.11-19
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• 2008

The problem of controlling asynchronous sequential machines is addressed in this paper Corrective control means to make behavior of an asynchronous sequential machine equal to that of a given model. The main objective is to develope a corrective controller, especially when a model is given as nondeterministic, or a set of reference models. We first review representation of nondeterministic models and model matching problems with nondeterministic models, which are presented in the companion paper. We then propose necessary and sufficient conditions for the existence of corrective controllers and describe their design procedure. To show the applicability, the proposed control scheme is demonstrated in an example.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.4
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• pp.7-14
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• 2010

Stable-state behaviors of asynchronous sequential machines represented as finite state machines can be corrected by feedback control schemes. In this paper, we propose a state feedback control scheme for input/state asynchronous machines with uncertain transitions. The considered asynchronous machine is deterministic, but its state transition function is partially known due to model uncertainty or inner logic errors. The control objective is to compensate the behavior of the closed-loop system so that it matches a sub-behavior of a prescribed model despite uncertain transitions. Furthermore, during the execution of corrective action, the controller reflects the exact knowledge of transitions into the next step, i.e., the range of the behavior of the closed-loop system can be enlarged through learning. The design procedure for the proposed controller is described in a case study.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.11
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• pp.404-416
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• 1983

This paper is concerned with the design automation of the sequential machines. The operations of sequential machine can be diveded into two types such as synchronous and asynchronous sequential machine and their realization is treated in separate mode. But, in order to integrate logic circuits in high volume, mixed mode sequential machine uses common circuitry that consists of gates and flip-flops. Proposed sequential machine can be designed by several method, which are hard-wired implementation, firmware realization by PLA and ROM. And then onr example shows the differnces among three design mothods. Finally, computer algorithm(called MINIPLA) is discussed for various application of mixed-mode sequential machine.

• Journal of IKEEE
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• v.24 no.3
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• pp.727-734
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• 2020

Fault tolerant corrective control for asynchronous sequential machines (ASMs) with transient faults is discussed in this paper. The considered ASM is vulnerable to a kind of faults whose manifestation may arise during transient transitions of the ASM, leading to transient faults occurring in non-fundamental mode. To overcome adverse effects caused by these faults, we present a novel corrective control scheme that can detect and tolerate transient faults in non-fundamental mode. The existence condition and design algorithm for an appropriate fault tolerant controller is addressed in the framework of corrective control theory. The applicability of the proposed control methodology is demonstrated in the FPGA experiment.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.40-47
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• 2011

This paper addresses the problem of fault detection and tolerance for asynchronous sequential machines using state feedback control. The considered asynchronous machine is affected by intermittent faults. When intermittent faults occur, the machine undergoes unauthorized state transitions and, for a finite duration, remains at the fault state, not responding to the change of the external input. In this paper, we postulate the scheme of detecting intermittent faults and present the existence condition and design algorithm for a robust state feedback controller that overcomes the adversarial effect of intermittent faults. We also undertake a comparative study between the previous control scheme for transient faults and the present strategy for intermittent faults. The design procedure for the proposed controller is described in a case study.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.9
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• pp.173-181
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• 2014

This paper addresses the problem of model matching control for a class of systems modeled as input/output asynchronous sequential machines. Based on the feedback control scheme, we design a corrective controller that compensates the behavior of the closed-loop system so as to match a reference model. Whereas the former studies use state observers and the output burst for designing a controller, the present research needs neither the observer nor the output burst in controller design. We define the 'output equivalent machine' of the considered machine to describe the existence condition and the construction algorithm for the proposed controller. A case study is provided to show the operation of the proposed corrective controller.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1440-1446
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• 2008

In this paper, a novel TMR (Triple Modular Redundancy) memory structure is proposed using state feedback control of asynchronous sequential machines. The main ability of the proposed structure is to correct the fault of SEU (Single Event Upset) asynchronously without resorting to the global synchronous clock. A state-feedback controller is combined with the TMR realized as a closed-loop asynchronous machine and corrective behavior is operated whenever an unauthorized state transition is observed so as to recover the failed state of the asynchronous machine to the original one. As a case study, an asynchronous machine modelling of TMR and the detailed procedure of controller construction are presented. A simulation results using VHDL shows the validity of the proposed scheme.