In complex environments, many distributed multiagent systems are described with the fractional-order dynamics.In this paper, containment control of fractional-order multiagent systems with multiple leader agents are studied. Firstly,the collaborative control of fractional-order multi-agent systems(FOMAS) with multiple leaders is analyzed in a directed network without delays. Then, by using Laplace transform and frequency domain theorem, containment consensus of networked FOMAS with time delays is investigated in an undirected network, and a critical value of delays is obtained to ensure the containment consensus of FOMAS. Finally, numerical simulations are shown to verify the results.
A novel image blind watermarking scheme based on Contourlet transform was proposed to embed color watermark image into color host image,which was different from some existing works using the binary or gray-level image as watermark.In the process of embedding watermark,each color component of the color host image was decomposed by Contourlet transform.Then,the low-pass sub-band coefficients were divided to 4×4 non-overlapping blocks,and the coefficients in the selected block were quantified for embedding the watermark information.In the process of extraction watermark,the watermark could be extracted from the watermarked image without the help of the original host image or the original watermark image.Experimental results show that the proposed color image scheme has better invisibility and stronger robustness against most attacks such as image compression,filtering,adding noise,cropping,rotation,and scaling.
The time management model for event processing in internet of things has a special and important requirement. Many events in real world applications are long-lasting events which have different time granularity with order or out-of-order. The temporal relationships among those events are often complex. An important issue of complex event processing is to extract patterns from event streams to support decision making in real-time. However, current time management model does not consider the unified solution about time granularity, time interval, time disorder, and the difference between workday calendar systems in different organizations. In this work, we analyze the preliminaries of temporal semantics of events. A tree-plan model of out-of-order durable events is proposed. A hybrid solution is correspondingly introduced. A case study is illustrated to explain the time constraints and the time optimization. Extensive experi? mental studies demonstrate the efficiency of our approach.
