Abstract: Series system, parallel system, r-out-of-n system and sequence system are typical in the engineering. Under the assumption that the repair time is negligible and the unit life has the identical exponential distribution, the analytical calculating method for failure probability and availability of the repairable typical system is proposed. The analytical calculating method has avoided the redundant Monte-Carlo simulation and computation, and has explicit physical meaning and high computational accuracy which is convenient for engineering application. The paper provides the practical method for determining the number of the spare parts of the typical system in engineering.
Abstract: This paper presents the software implementation of a feedback control for the two axes of an XY table and the simulations of motor X and motor y velocity responses to the specific step inputs. The object of the software is to guide the “tool point” around the outside edge of a planar “workpiece” under computer control. PWM method and P control philosophy are used in the control. By means of least-squares estimation, the values of coefficients in the discrete modes for the controlled motors are determined. The results show that the control strategy is practical and the simulations are valid.
Abstract: In the Earthquake Precursory Forecast industry, despite the ample amount of instruments and data resources owned by the research institutes and organizations, difficulties such as instrument access, lack of diversity in process means of collected data, collection of data across layers still exist due to difference of equipment type and the degree of information among different institutes. On the base of research and analysis about the device resource characters and collaborative application in Earthquake Precursory Forecast, we design and realize the middleware of device collaboration. The practice operation shows that the middleware can meet the demands of device resource’s reliability, efficiency and collaboration in Earthquake Precursory Forecast industry.
Abstract: A new approach of structure synthesis of 3-DoF compliant parallel manipulators with flexure hinge is proposed in this paper. Based on characteristics of flexure hinge and topology optimal method, the kinematics of the 3-DOF perpendicular compliant parallel manipulator with flexure hinge and its control system are developed. The parallel manipulator is driven by three piezoelectric actuators and the three actuators in this mechanism are arranged according to the Cartesian coordinate system. Experiments are conducted to give some validation of the theoretical analysis.
Abstract: To improve the modeling accuracy of grey model and broaden its application fields, a non-homogeneous index grey model (termed NIGM(1,1,k)) was built, which is based on the non-homogeneous dispersion index function and the formula computing the parameters of grey model NIGM(1,1,k) was proposed through the least square method. The function of the time response sequence of the proposed grey model was solved by taking differential equations as a deductive reasoning tool. The proposed grey NIGM(1,1,k) model has the characteristic of high precision as well as high adaptability. Examples validate the practicability and reliability of the proposed model.
Abstract: Random number is widely used in computer application. What is used commonly in practice is pseudo-random number generated by mathematical algorithm. Several useful pseudo-random number generating algorithm and random testing methods are discussed. And according to the disadvantage of traditional algorithm, improvement of pseudo-random number generating algorithm and some new methods to generate real-random number are summarized and analyzed.
Abstract: Poor information means incomplete and insufficient information, such as small sample and unknown distribution. For point estimation under the condition of poor information, the statistical methods relied on large samples and known distributions may become ineffective. For this end, a fusion method is proposed. The fusion method develops five methods, three concepts, and one rule. The five methods include the rolling mean method, the membership function method, the maximum membership grade method, the moving bootstrap method, and the arithmetic mean method. The three concepts comprise the solution set on the estimated true value, the fusion series, and the final estimated true value. The rule is the range rule. The method proposed can supply a foundation for the true value estimation of manufacturing quality under the condition of poor information.
Abstract: Based on the fusion method for the true value estimation under the condition of poor information, the experiment is conducted in this paper. The results of simulation of the uniform distribution and experimental investigation on the manufacturing quality evaluation for the tapered roller bearing indicate that the fusion method allows the number of the data little and the distribution unknown, having the reliable estimated result.
Abstract: A new type of hybrid desiccant air conditioning system combining an active desiccant wheel with a conventional front-positioned cooling coil is presented, in which Type Ⅲ desiccant is used in the active desiccant wheel. Then a preliminary experiment is carried out in order to investigate the feasibility of the hybrid desiccant system serving as a dedicated outdoor air system (DOAS). The result shows: under the two typical outdoor air conditions in the area of South China, the desiccant system which only needs to adopt a regeneration temperature of 45°C without lowering the cooling coil temperature can satisfy the requirements of the dehumidification; when operating in the climate with a high humidity of 90% and a high-temperature of no more than 36.5°C, the desiccant system only driven at a regeneration temperature of 60°C can also provide enough dehumidifying capacity; but compared with the active desiccant wheel using Type Ⅰor Type Ⅱ desiccant, this system can not reach a lower dew point. Therefore, this system can operate effectively at a moderate regeneration temperature, suitable for the high quality and comfortable air conditioning.
Abstract: At most fire scenes, electric short circuit (ESC) arc beads that may be provide useful information on the cause and development of the fire are found. Various physical or chemical methods have been proposed for identifying these electric short circuit beads to be either the cause of a fire (primary arc beads) or one caused by the flames of the fire (secondary arc beads). Little was studied, however, on their identification using the cupreous oxides formed in the molten marks. In this study, the concentration of metallic Cu and Cu2O in the surface region and subsurface was quantified by X-ray photoelectron spectroscopy (XPS). As a result, it can be examined to distinguish the primary and secondary arc beads by comparing the distribution of the substances of Cu and Cu2O.