• Journal of Institute of Control, Robotics and Systems
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• v.12 no.7
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• pp.719-727
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• 2006

This paper proposes a new method to obtain a maximum allowable delay bound for a scheduling of networked discrete control systems and event-based scheduling method. The proposed method is formulated in terms of linear matrix inequalities and can give a much less conservative delay bound than the existing methods. A network scheduling method is presented based on the delay obtained through the proposed method, and it can adjust the sampling period to allocate same utilization to each control loop. The presented method can handle three types of data (sporadic, emergency data, periodic data and non real-time message) and guarantees real-time transmission of periodic and sporadic emergency data using modified EDF scheduling method.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1432-1435
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• 1996

This paper obtains maximum allowable delay bounds for stability of network-based control systems and presents a network scheduling method which makes the network-induced delay be less than the maximum allowable delay bound. The maximum allowable delay bounds are obtained using the Lyapunov theorem. Using the network scheduling method, the bandwidth of a network can be allocated to each node and the sampling period of each sensor and controller can be determined. The presented method can handle three kinds of data (periodic, real-time asynchronous, and non real-time asynchronous data) and guarantee real-time transmissions of real-time synchronous data and periodic data, and possible transmissions of non real-time asynchronous data. The proposed method is shown to be useful by examples in two types of network protocols such as the token control and the central control.

• Explosives and Blasting
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• v.33 no.3
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• pp.29-50
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• 2015

Safe blast criteria based on the concept of scaled distances can be obtained from the statistical analysis on measured peak particle velocity data of blast vibrations. Two types of scaled distance widely used in Korea are the square root scaled distance (SRSD) and cube root scaled distance (CRSD). In contrast to SRSD scheme, however, the function of maximum charge per delay for CRSD increases without bound after the intersection point of these two functions despite of the similar goodness of fits. To prevent structural damage that may be caused by the excessive charge in the case of CRSD, it is suggested that CRSD be used within a specified distance slightly beyond the intersection point. On the other hand, there are several attempts that predict vibration level(VL) from the peak particle velocity(PPV) or estimate VL based on the scaled distances without considering their frequency spectra. It appears that these attempts are conducted in blasting contracts only for the purpose of satisfying the environment-related law, which mainly deals with the annoyance aspects of noises and vibrations in human life. But, in principle there could no correlation between peaks of velocity and acceleration over entire frequency spectrum. Therefore, such correlations or estimations should be conducted only between the waves with the same or very similar frequency spectra. Finally, it is a known fact that structural damage due to ground vibration is related to PPV level, the safety level criteria for structures should be defined by allowable PPV levels together with their zero crossing frequencies (ZCF).