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Segmentation of natural image with complex textures is a challenge problem for classical Active Contour Models, because it is difficult to find a suitable measure for describing textures that always occupy a big area of natural image. In this paper, a new measure to evaluate texture complexity is proposed, then a feature map is created based on this measure. To approximate two phase image, diffusion filter is used to smooth the feature map. Finally, we proposed a new Active Contour Model based on the feature map. This new Active Contour Model can be used to segment natural image. Results of experiments on some typical natural images show the proposed model suffer from less over and wrong segmentation than state-of-the-art models.

This paper provides an overview of literature in recent five years on the state of the art of in-pipe inspection and cleaning robots. Firstly the overview explains the reasons why inpipe robots play a very important role in the rapid development of modern industry. Secondly, according to existent researches, type and feature of the traditional in-pipe robots have been systematically generalized which can be found in tablel and table2. Furthermore, the review specifically clarifies and analyses the latest conception and design of in-pipe robot from the global research institute after 2010, which are to solve the different kinds of difficulties in specially complicated working circumstances, such as vertical pipe, variable diameters, elbow pipe, branch pipe, mini pipe and poor driving force. Lastly, a conclusion about advantage and disadvantage of in-pipe robot is drew and the studying hotspot and trend in future for in-pipe robots are forecasted.

In recent decades, a lot of research has been done on snake-like robots. There has been a new revolution in theory and implementation of snake-like robots. It enlarges the field of robotic application. A literature survey of researches on snake-like robots theory is provided biomechanical studies of biological snakes, kinematics and dynamics modeling, control system analysis. The research theory results are elaborated systemically. In particular, control system is introduced ulteriorly, which are control based on morphology, kinematics and dynamics, CPG. Then classifications of typical snake-like robots are presented according to the differences of structures and movement types. Representative snake-like robot bodies are described targetedly in detail. Finally, the development of snake-like robots is predicted. The overview shows that the majority of literature on snake-like robots so far has focused on experiment instead of the real, but there is a growing trend towards locomotion in realistic environments that are more challenging in future.

We give an abstract condition for Riesz basis generation for discrete operators in Hilbert space, from which we show that the generalized eigenfunctions of a Euler-Bernoulli beam equation with boundary linear feedback control form a Riesz basis for the state Hilbert space. As a consequence, the asymptotic expression of eigenvalues as well as exponential stability are readily presented.

Two uniform Euler-Bernoulli beams connected by a spring which models the vibration of two flexible arms is considered. It is shown that the direct strain feedback control which makes the closed-loop system of a single beam exponentially stable also works for current case when the spring mass is less than a fixed value. The closed-loop system is shown to be a Riesz system and the general condition for the exponential stability of the system is presented.