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This paper investigates exponential stability of nonlinear delayed impulsive systems. The effects of impulses with sufficiently small input delays and arbitrary sizes of input delays are thoroughly examined according to whether the continuous dynamics of the systems is stable. Several exponential stability criteria are obtained and are then applied to study constant time-delay systems with linear input impulses. Numerical examples are provided to illustrate the usefulness of the main study results.

This paper has researched the influence of the probability distribution of all the random bounded communication links delays on the global error of clock synchronization for the least square estimation based time synchronization algorithm (LSTS) over wireless sensor networks (WSNs). First we have presented the large influence of the probability distribution of random bounded communication delays on the global error of clock synchronization under the general condition of communication in WSNs. Then the information of round-trip delays has been introduced to compensate the clock offset in order to decrease the global error of clock synchronization based on the fact that all the round-trip delays between each pair of sensor nodes can be accurately measured. The characteristics of the round-trip delay are analyzed in the case of bidirectional communication between sensor nodes. The clock offset is compensated by the round-trip delay, and the attenuation factor in the consistency theory is introduced. The combined control can greatly decrease the expectation of the global error, the variance of which is also reduced moderately at the same time. Meanwhile the adjusting amplitude of the clock offset also drops sharply. Finally it has shown that the global error of clock skew compensation is mostly determined by the variance rather than the expectation of random communication delays through simulations for the improved algorithm, while the global steady-state error is largely decided by the expectation of random communication delays.

In order to tackle the problem of random communication delays in time synchronization process, this paper has mainly discussed the relationship between the global steady-state error of clock synchronization and the probability distribution of the delays of all the communication links for least square estimation based time synchronization algorithm (LSTS) in wireless sensor networks ( WSNs ). First under the general condition of communication in WSNs, it has been described that the probability distribution of bounded random communication delays has a great influence on the clock synchronization error. Then considering that all round-trip delays can be determined correctly between every pair of sensor nodes, the update rule of clock offset compensation has introduced round-trip delays so as to reduce the adjusting amplitude of the clock offset and the error of clock synchronization. Finally simulations for the improved algorithm has been given. It is shown that the error of clock skew compensation mainly depends on the variance of random communication delays rather than expectation, while the global synchronization error depends on the expectation of communication delays. The introduction of round-trip delay in LSTS algorithm can decrease both the expectation and the variance of clock synchronization error.

This paper concerns globally exponential synchronization for a class of impulsive networks with time-delays. The strategy is based on pinning control: single controller is designed to pin the whole network and realize synchronization. Some new conditions are imposed on impulsive sequences, which make the results obtained in this paper less conservative. A numerical example is supplied to illustrate the validity of the main results.

This study investigates the exponential stability problems of singular impulsive switched systems. Using the switched Lyapunov function method and algebraic inequality, sufficient conditions are expressed as arbitrary and conditioned impulsive switching has been obtained. In addition, with the introduction of the impulsive controller, several exponential stability criteria are derived when the impulsive controllers are stabilising. Finally, two numerical examples are provided to illustrate the effectiveness of the proposed criteria.

This work investigated the effects of two types of algogenic organic matter (AOM), namely Anabaena AOM and Chlorella AOM, on the removal of naproxen using three different nanofiltration (NF) membranes. The effects of AOM membrane fouling on the rejection of naproxen were interpreted with respect to the AOM molecular weights (MW) and the fouling characteristics. Organics with medium and low molecular weights, e.g., less than the 10 kDa of the Anabaena AOM and Chlorella AOM, significantly affected the naproxen removal and resulting membrane fouling. Anabaena AOM and Chlorella AOM with large and medium MW (> 1.5 kDa) adhered well to the NF membranes to form a fouling layer, which enhanced the hydrophobicity and negative charge of the membrane surface. The hydrophobicity and electronegativity of the adhered AOM fouling layer was responsible for the decreased membrane flux and the increased naproxen removal. During the filtration process, AOMs with low MW could enter the membrane pores, which also affected the naproxen removal and resultant membrane fouling. Anabaena AOM contained more hydrophobic organics than Chlorella AOM, whose cohesion free energy and adhesion free energy between the membrane and foulants were more negative and caused more severe membrane fouling and a higher naproxen removal effect, or, more specifically, the degree of membrane flux declined from 7.0% to 18.8% and naproxen retention increased from 7.3% to 15.1% in the presence of Anabaena AOM, while which from 3.0% to 15.4% and from 3.9% to 12.3% in the presence of Chlorella AOM, respectively. The surface free energies of the membranes and foulants is a useful parameter for membrane fouling analysis, and a mechanism for the enhanced naproxen removal in the presence of AOM was also proposed.

Nanofiltration (NF) membrane fouling caused by two types of natural dissolved organic matter (DOM), namely Qingcaosha reservoir (QCS) DOM and Taihu Lake (TH) DOM, on naproxen (NPX) retention, were assessed. The results indicated that NPX retention could be interpreted with respect to the DOM molecular weights (MW) and the fouling characteristics. Organics with medium- and low-MW, e.g. less than 10 kDa, significantly affected NPX retention and resulted in membrane fouling. DOMs with medium MW (1.5–10 kDa) mainly had strong hydrophobic characteristics, and adhered well to the NF membrane surface to form a fouling layer, which altered the hydrophobicity and negative charge of the membrane surface. The hydrophobicity and electronegativity of the adhered DOM fouling layer was responsible for the decreased membrane flux and the change in NPX retention. TH DOM contained more hydrophobic organics with MW 1.5–10 kDa than QCS DOM, and the cohesion free energy and adhesion free energy between the membrane an...

This paper investigates synchronization problem of nonlinearly coupled dynamical networks, and an effectively impulsive control scheme is proposed to synchronize the network onto the objective state. Based on the stability analysis of impulsive differential equations, a low-dimensional sufficient condition is derived to guarantee the exponential synchronization in virtual of average impulsive interval. A numerical example is given to illustrate the effectiveness and feasibility of the proposed methods and results.

The vision-based dynamic gesture recognition technology has characteristics of good flexibility, strong expansibility, and low cost, etc. The gesture interaction has become popular in recent years. The gesture segmentation is the basis of this technology, which directly influences the subsequent prcedures. Based on the YCrCb ellipse skin model and background subtraction, this paper proposes a new gesture segmentation method that combines these two methods. The proposed method is capable of removing interferences of skin color points and background, and thus improves the effect of gesture segmentation. In addition, the gesture position can be determined by marking the connected region of the binary image obtained by gesture segmentation. Compared with the existing skin segmentation and background subtraction methods, the proposed method has achieved higher accuracy of segmentation.

This paper investigates synchronization of coupled chaotic systems by means of modified impulsive controller. The modified impulsive controller is an addition of an integral term of the errors, which is different from the normal impulsive one. Some novel criteria on synchronization of such chaotic systems are derived by utilizing the stability analysis of impulsive differential equations and differential inequalities.

Transportation is the fundamental and antecedent sector in the national economy, whose equity provides opportunity equity for economic development. This paper researches the meaning of transportation equity and makes suggestions in transportation equity policy choice on the basis of equilibrium degree analysis of China's regional transportation equity and problem. This paper can provide a reference for relevant department, which have important practical significance to ensure transportation equity.

According to the needs of high-speed rail slab factory manufacturing resources management, analyzing the features of the rail slab production and the problems encountered in the process of implementing the MRPII system from applicable aspect, system requirements of the rail slab factory implementing MRPII and key technologies of developing the system are put forward, which include the design of rough slabs master production scheduling, rail slab storage area view management, rail slab archives management and so on.

A new convenient method has been developed for the synthesis of well-defined aniline oligomers containing 3 to 8 aromatic amine units with amino or aryl end-groups. The method consists of a single-step reaction of the aromatic amines having at least one amino end-group with other aromatic amines in an acidic medium with or without external oxidizing agents. The oxidation state of the oligomers can be changed via simple redox reactions. A possible mechanism for the reaction involves an electrophilic aromatic substitution of nitrenium cation to aromatic amines.

This paper investigates global exponential synchronization of chaotic systems by designing a novel impulsive controller. The novel impulsive controller is a combination of current and past error states, which is a modification of the normal impulsive one. Some global exponential stability criteria are derived for the error system by utilizing the stability analysis of impulsive differential equations and differential inequalities and, moreover, the exponential convergence rate can be specified. An illustrative example is given to show the effectiveness of the modified impulsive control scheme.