Advanced Materials Research Vols. 562-564

Abstract: Extraction of frequent patterns in transaction-oriented database is crucial to several data mining tasks such as association rule generation, time series analysis, classification, etc. An Efficient Parallel algorithm for Mining frequent pattern (EPM) was proposed and Fast Distributed association rules Mining (FDM) algorithm was improved. Hash table technology was used to improve the generation efficiency of the 2nd candidate items . It also reduces the number of transactions in transaction database using Tid table technology. A master-slave model of parallel algorithm for mining association rules is designed in the algorithm to reduce the communication cost. The experimental results show that this algorithm has a high efficiency to deal with large database.

Abstract: Digital City is the digital technical service system which is synthetically applying such as Geographical Information System (GIS), Remote Sensing (RS) ，Satellite Positioning System, Computer Network, Multimedia, Virtual Simulation and so on many kinds of technical methods, automatically gathers and dynamically manages City’s infrastructure, function mechanism, and at last assists Decision-making Supports. The Three-Dimensional Urban GIS (3D UGIS) is the key supporting technology of the Digital City, and also needs certain key technology to support it. Such as building 3D Spatial Data Model, huge spatial data’s storage method in spatial database, and reconstructing 3D virtual scene. And this thesis precisely centers on these key problems to launch research.

Abstract: This paper presents a new method, based on Elman neural network approach for structural parameter identification. According to the Features of shear-type structure, Proposed identification strategy of the structure parameter and damage detection method. Determine the structural damage and Recognition of damage location and extent of damage by comparing different periods of the structure stiffness. Simulation results show that this method identified structural stiffness values are still high accuracy, and to achieve accurate identification and location of structural damage.

Abstract: For the cast-steel joint of large span roof system, the main difficulties of prototype stress test encountered are the large scale of the structure system, large loading system and large supporting system, etc. The hydraulic jack of high tonnage is adopted to apply the load. The frame structure of channel steel is used to fix the cast-steel joint and the loading system. The reverse loading system is elaborated to simulate the axial tensile force. So prototype stress test on the cast-steel joint of large span roof system is accomplished successfully. The test results show that, under the designing load condition, cast-steel joint is in a linear elastic state, the structure is globally safe; the maximum surface stress of cast-steel joint is adjacent to the crossing point of steel pipes; the stress value of test is well coincident with one of finite element analysis. This test device system is especially suitable for the stress state test of large components, and can also provide important reference to the similar projects.

Abstract: According to the chatter marks on strip steel of HC cold rolling mill , by analysis the collected vibration and simulation analysis on rolling mill, it is found that chatter marks of strip steel surface cuased by the Seventh-order natural frequency. Then, for analysising cuase of chatter marks on strip steel surface, relevant inhibiting chatter marks measures is put forward, and the measures are used for production which got a good inhibition effect of chatter marks.

Abstract: The three-dimensional unsteady turbulent flow of rotational flow self-priming pump was simulated by using Reynolds time-averaged N-S equations and the standard k-ε turbulent model, sliding mesh model of static-dynamic coupled models and SIMPLE arithmetic. The static pressure distribution of the pump central rotative surface and relative velocity of the impeller central rotative surface in a complete application cycle were analyzed. The rule of instantaneous head in a impeller channel cycle was studied, and the positions of maximal head and minimal head were analyzed. It revealed that the unsteady method can truly simulate the changes of the rotational flow self-priming pump interior flow, and the unsteady characteristic of interior flow in rotational flow self-priming pump is obvious and it changes as the relative position of impeller and volute change. The change is periodical, and its frequency is relate to the impeller number and the rotate speed of the pump.

Abstract: The trend of modern high-end CNC equipment with high reliability and long life expectancy makes traditional methods of equipment reliability assessment difficult due to the multiple performance parameters as well as less failures and degradation data. This paper proposes a performance reliability assessment based on parameter degradation data, which deals with reliability evaluation with small numbers of samples. With the analysis of performance degradation processes and rules, the framework of the performance reliability assessment for parameters is proposed. According to the degradation data of a single performance parameter, the degradation trajectory of the performance parameters is curve fitted by Support vector machines (SVM). The reliability when the degradation curve reaches its specified threshold is calculated. The probability density function at time is also built, which describes the shape of the failure distribution of each performance parameter at each stage in time. Finally, using a specific type of CNC machine tool as an example, the performance reliability assessment method is verified.

Abstract: The modern high-end CNC equipment with high reliability and long life expectancy makes traditional methods of equipment reliability assessment difficult due to the multiple performance parameters as well as less failures and degradation data. This paper proposes a performance reliability assessment based on multiple parameter degradation data, which deals with reliability evaluation with small numbers of samples. With the analysis of performance degradation processes and rules, the framework of the performance reliability assessment for multiple parameters is proposed. Using the degradation data of multiple performance parameters of CNC equipment, a covariance matrix is built to determine the correlation between the performance parameters. The degradation trajectories of the performance parameter(s) are curve fitted by Support vector machines (SVM). The reliability when the degradation curve reaches its specified threshold is calculated. According to both the reliabilities of non-relevant performance parameters and relevant performance parameters, the joint reliability of the system is calculated. Finally, using a specific type of CNC machine tool as an example, the performance reliability assessment method is verified.

Abstract: A novel, environmental friendly dynamic rotating electromagnetic heating-magnetizing device is proposed, which can heat up and magnetize the low temperature feed water of reverse osmosis system. The device converts input mechanical energy into heat energy completely. The structure and operation mechanism are discussed in detail, and the mathematical model of loss is established based on fundamental electromagnetic field theory. At last, the effects of water magnetization treated by the device are introduced, which inhibits scaling on the reverse osmosis membrane surface and slows down the corrosion of metal surface.

Abstract: This paper discusses the FWP bending deformation processing computing problems. Using Rayleigh-Leeds method to solve the flexible part bending deformation. Designing flexible part bending deformation test function. Finding out the flexible part itself material characteristics, the relationship between Fz and deformation through satisfying FWP processing process of a flexible minimum potential energy conditions to work out the approximate solution of the flexible part bending deformation. Finally, think a rectangular flexible workpiece that made of polyurethane sponge as an experiment subject. The results show that the calculated results of the average of the relative deviation are only 6.85%. Proof that this bending deformation test functions satisfies the actual deformation calculation requirements.