Key Engineering Materials Vols. 467-469

Abstract: Traditional digital watermarking usually adopts the gray image as hidden information, more embedded information result in largely modifying more image data. Binary image can guarantee good affection of human vision, a bit-decomposition adaptive watermarking algorithm based on the mask is proposed. According to the superiority of binary, classifying binary images to three kinds of sub graph (High, Middle, and Low-sub graph); multi-masks are constructed by the importance of different sub graphs and cover the original image. Experimental results demonstrate the proposed scheme not only has better visual quality, but also is very robust to common image processing and geometric attacks.

Abstract: In IT outsourcing, contract defects often cause outsourcing failure. Many client firms do not know well how to design the contract because they have no way to access private information of vendors, so vendors are likely to conduct out of constraint. This work combined relational contract with conventional one to establish an integral management mechanism. It at first gave the cost-increment analysis method to improve relational contract design so that it would facilitate outsourcing contract to work efficiently. Then analyzed the relation between vendor profit-gaining and its varied conducts, and built up the method of contract design to allow vendor gaining profit only when it conducts following its true types. In the method, the private information was sorted into a variety of conduct types and universal decision was found out aiming all the types. The mechanism effectively incents and constrains vendors without relying on private information.

Abstract: This paper focuses on the problem of detecting sensor faults in feedback control systems with multistage RBF neural network ensemble-based estimators. The sensor fault detection framework is introduced. The modeling process of the estimator is presented. Fault detection is accomplished by evaluating residuals, which are the differences between the actual values of sensor outputs and the estimated values. The particular feature of the fault detection approach is using the data sequences of multi-sensor readings and controller outputs to establish the bank of estimators and fault-sensitive detectors. A detectability study has also been done with the additive type of sensor faults. The effectiveness of the proposed approach is demonstrated by means of three tank system experiment results.

Abstract: An air supply control method of VAV system based on BP neural network is proposed in this paper, which combines with the recurrent wavelet neural network model, predictive control and optimization of parameters. With the proposed method, the air volume of the VAV system can be controlled accurately even if the change of the air is nonlinear and time-lapse. Compared with tradition control method, it has the advantages of rapidly converging, high control precision, strong skills of learning and wide application prospect.

Abstract: Additives will affect directly the clinic operational properties of investment materials, and finally affect the quality of castings. The relationship between additions and properties of the mullite-based investments has been studied. This paper describes effect of HBO3, Na5P3O10 and (NaPO3)6 on properties (including fluidity, initial setting time and compressive strength) of the mullite-based investment materials.It is found that with addition of HBO3, the fluidity of the mullite-based investment materials improves greatly, the initial setting time prolongs, and the compressive strength of investment materials changes little；with addition of Na5P3O10, the fluidity of mullite-based investments improves greatly, the compression strength increases, and the amount of silica gel decreases clearly；with addition of (NaPO3)5, the fluidity of mullite-based investments increases, the initial setting time prolongs, the compression strength decreases, and the amount of silica gel decreases clearly.

Abstract: This paper studied a one-dimensional model of high-vacuum plane circular gas-bearing with a three-stage sealing system, and analyzed the performances of the high-vacuum gas-bearing by combining the finite element method and the flow rate principle of the vacuum technology. For an expected pressure in the vacuum chamber, the zero load-capacity accident could take place. The reasons for the zero load-capacity accident were given through analyzing the flow rate of each sealing stage while the relationship between the pressure in the vacuum chamber and the inlet pressure was obtained. Besides, the influences of many parameters on the vacuum degree limit of the vacuum chamber were examined carefully. The analysis in this paper showed that for a given multi-stage seal system, the vacuum degree limit of the vacuum-chamber was inherent at the nonzero load-capacity condition.

Abstract: This paper presents the method to estimate curing profile's parameters for curing process of Moisture Resistance Cyanate Ester (MRCE) based underfill used in Flip Chip Ceramic Ball Grid Array (FC-CBGA). The two steps curing profile was found to eliminate voids formation in underfill during curing process. The important parameters in two steps curing profile such as first fixed temperature and duration of second temperature rise were estimated by superimposed of cure initiation curve and weight percentage loss curve of underfill epoxy material. Differential Scanning Calorimeter (DSC) analysis was carried out to characterize the cure kinetics reaction of underfill epoxy and produced the cure initiation curve. Thermal Gravimetric Analysis (TGA) was performed to characterize the weight loss of underfill and produced the weight loss curve. It was estimated that the first fixed temperature and duration of second temperature rise for two steps curing profile were 100 oC and 60-80 minutes respectively. The simulation experiment was conducted to verify the profile and no voids formation observed along this curing process.

Abstract: Aiming at the forward topics of self-adapting Internetware, relying on the practical software engineering technology and previous research achievements of tackling key problems of SoftMan, the paper puts forward a novel component model ——SMC(SoftMan Component), which processes reflectivity, opening, adapting and supporting nested assembly and self-adjusting its internal architecture. Furthermore, the basic design specifications of APIs are described in detail. By the special structure of Component Body, SMC forms a hierarchical management domain which is of explicit constraint of father-child between component and its children, and thus it flexibly integrates control mechanisms for sub-components, such as interface introspection, lifecycle, interaction binding, dynamic configuration, etc., into its pluggable controllers so as to be endowed with the ability to change its behavior and architecture when the application must evolve to cope with user requirements and new context. Initial experiments demonstrate that SMC can give effective support for dynamic reconfiguration during running, and it takes on own technical characteristics compared with other component models.

Abstract: A novel adaptive fuzzy sliding mode predictive control (AFSMPC) method for solving the networked launch vehicle attitude control system with network-induced delay, uncertain parameters and outer disturbances is proposed in this paper for the attitude stabilization of the networked launch vehicle control system. The proposed sliding mode surface includes a predictor to compensate for the network-induced delay of the NCS. Then, for the networked Launch vehicle attitude control system with uncertain parameters and outer disturbances, a total sliding-mode control system is proposed, which is designed without the reaching phase of a conventional sliding-mode control. In order to attenuate the chattering phenomena brought by the proposed control, a fuzzy logic system is designed to mimic the good behavior of a total sliding-mode predictive control system. Finally, Simulation results show that the proposed control scheme is effective.

Abstract: Aiming at the spectrum analysis, the classification of PWM strategies based on digital implementation for the three-phase inverter is given. Then the paper summaries the three spectrum analysis methods: theoretical expression, computer simulation and experiment. The structure and procedure of each method are discussed. Each method has advantages and disadvantages. The experiment and computer simulation can be used to analyze any PWM strategy. The theoretical expression is always used to analyze the deterministic strategies.