Key Engineering Materials Vols. 474-476

Abstract: It is an inevitable problem that how to select appropriate partner in case of constructing supply chain network taking contractor or owner as main body in the building engineering construction. Based on reference of existing research results of supplier evaluation index system and combining with main evaluation index of building construction, the paper built evaluation index system of building engineering materials supplier and introduced ANP that combining qualitative and quantitative method to select optimal supplier. Supplier selection example of some large scale building material supplier selection based on Super Decision verifies the feasibility of ANP selection method proposed in the paper.

Abstract: PID controllers are widely used in the Wastewater treatment plants. However the existence of the control disturbance and measurement error may greatly reduce the controller's stabilization, and even lead the control to failure. In order to improve the performance capacity, a new compound control method based on the cerebellar model articulation controller (CMAC) is proposed. We adapt the traditional PID controller to realize the feedback control and CMAC controller to realize the feed forward control. For real-time control, Altera Nios II FPGA (Field Programmable Gate Array) is employed to construct a hardware-in-the-loop system through writing C and VHDL codes on this FPGA. The control results revealed the compound CMAC-PID controller had excellent control performance such as systemic stability, disturbance resistance, fast response rate and small overshoot. It can be concluded that the compound controller is robust, self adaptive and effective.

Abstract: This paper investigates the robust control problem of the uncertain unified chaotic systems subject to sector input nonlinearity. First, the adaptive parameter is introduced for designing sliding surface such that the parameters of the unified chaotic system are not necessary to know. Then, based on Lyapunov theory, the controller is designed via sliding mode technique, which cancels the assumption that the information on the bound of input nonlinearity should be known for designer in advance. Finally, the sliding mode controller is applied to ensure that different uncertain chaotic systems (Lorenz system, Lü system and Chen system) states can be regulated to zero levels asymptotically in the presence of sector input nonlinearity. The simulation results demonstrated the effectiveness of the proposed controller.

Abstract: In this paper, we propose a generalized projective synchronization with different scaling factor for fractional-order chaotic systems with different fractional order. A method of constructing response system is given. The generalized projective synchronization conditions are obtained theoretically. Finally, the fractional-order Chen system is used to demonstrate the effectiveness of the proposed schemes.

Abstract: A kind of hyper-dispersant(MA) was synthesized as compatibilizer between PE/OMMT composite. when the weight ratio of PE/OMMT/MA was 100:2:0.5,the composites had outstanding machine performances. SEM micrograph indicated that the PE/OMMT/MA composites mixed uniformly compared to PE/OMMT composites, and TEM test showed that PE had entered into layers of montmorillonite to form intercalated composites.

Abstract: This paper try to predict fatigue based on a GA – BP algorithm. GA algorithm is the ideal tool to cope with high efficient learning methods and optimization for topological structure of networks for BP. Compared the predicted result with the tested result and find that this method has relatively high accuracy.

Abstract: This paper proposes an improved web crawler algorithm to climb more useful information since the basic web crawler algorithm is low-efficiency and easy to climb useless repeated information. By the proposed algorithm, the website urls are hierarchical saved to store websites overall topology, which will make crisscross complex web URL system from a graphic structure into a tree structure. The actual website BBS experiments show that the algorithm is much better than the basic web crawler algorithm in crawling speed and download information such as the usefulness of baking. Furthermore, it provides a performing structure mode for the increment crawler algorithm.

Abstract: Although DCP (Dynamic Cone Penetrometer) cannot directly reflect the subgrade compaction degree, experience shows that the smaller DCP penetration rate is and the better the compaction quality will be. Tai-Ao highway in China is selected as an engineering example, some relationship curves are obtained by in-situ tests, such as total hammering number of DCP and penetration depth, and penetration ratio and penetration depth, and these curves reveal that DCP can reflect the compaction quality in some degree. And then a lot of FWD and DCP are in-situ tested on the same points of filled and excavated subgrade, and the back-calculated CBR and FWD (1 ton, 3 ton and 5 ton) are analyzed and they have better correlation, and DCP is approved to be a better manner to test and evaluate the compaction quality of highway subgrade.

Abstract: Distributed Denial of Service (DDoS) imposes a very serious threat to the stability of the Internet. Compared with many detection approaches, detecting DDoS attacks based on entropy has advantages such as simplicity, high sensitivity and low false positive rate. But the method with single attribute entropy has high false positive rate when detecting attribute forged attacks. This paper presents a detecting method based on joint entropy and a filtering way based on conditional entropy. The efficiency of this scheme is validated with simulation on the research lab network.

Abstract: The oxidation behaviour of developed Fe₈₀Cr₂₀ alloy and commercial ferritic steel at 1173 - 1373 K in air is studied. Effects of crystallite size and titanium implantation on the oxidation behaviour of specimens were analyzed based on oxide morphologies and microstructures. Oxide scales characterisations of specimen after oxidized were identified by X-ray diffraction (XRD). The surface morphology of oxide scales were examined with scanning electronic microscope (SEM) and energy dispersive X-ray analysis (EDX). The rate constant of oxidation were determined using Wagner method. The results show that crystallite size and titanium implantation has remarkably enhanced the oxidation resistance. The oxidation kinetics indicate that the developed Fe₈₀Cr₂₀ as the finer crystallite size both unimplanted and implanted specimens show better performance.