Dynamic data exchange based on STEP-OODB for network-supported collaborative design

This paper analyzes the features of data for network-supported collaborative design, researches the data transformation, the data transmission and the data transaction of collaborative design. The system configuration and organization mode of dynamic data exchange for network-supported collaborative design are developed, in which, STEP serves as the product data exchange standard, what's more, Object-Oriented Database (OODB) is the kernel database of the system, so that each of the CAD systems can synchronously access the OODB, share and exchange the design information. The STEP-OODB serves as the organizing mode of dynamic data exchange for the network-supported collaborative design based on Internet, which realizes the real-time exchange and consistency of the dynamic data among the cross-platforms and CAD systems.     

Constructing organization network for community-oriented collaborative product design

Community-oriented collaborative design is an emergent form of collaborative product development, in which the range of collaborative partners extends to wide area community members. It is difficult to construct the organization network because the accurate features of the wide area community members are hard to access. Aiming at this problem, an organization network constructing method based on bidding mechanism is proposed. First, the bidding process based on contract net with confirmation protocol (CNCP) is presented. Then, considering the false profit declared by the bidders, a multiple rounds bidding process combined with genetic algorithm (GA) is used to get the best sub-projects allocation scheme, in which the total payment of sub-projects is minimal and the project due time is satisfied. A case analysis shows that the method can eliminate the false profit declared by the bidders and provides an operable way to construct network organization for community-oriented collaborative design.     

State and Prospects of Physics-Based Free-form Surface Modeling

Physics based modeling is one of the keen free form surface modeling method at present, and it should be a practical surface modeling method in the future. In Physics based modeling, the object is viewed as a physics and not a pure geometry model. According to its physics principle and math representation, the physics based models are mainly classified into two types:energy model and dynamic Lagrangian model. The fundamental theory is introduced, and the principle, development and application state of each model is reviewed. To provide designer more naturally design ability and to introduce more flexible geometric modeling methods are the prospect of future researches on physics based free form surface modeling is outlined at last.     

An evaluation method of design ability usingmental workload assessment

By analyzing the relationship between design ability and design time, mental workload, and design effect, an evaluation method of design ability is proposed. As far as the factors involved in such method are concerned, mental workload is measured by NASATLX (national aeronautics and space administration task load index) scale, design time is acquired with a special program, and design effect is scored by expert. Then, the time spent on new design tasks based on the evaluated ability level is predicted by using support vector machines, which is then compared with real measured time. The result shows that the predicted time is well accorded with the real time, which indicates that the evaluation method of design ability is valid.     

An anti-“shilling attacks” collaborative filtering algorithm based on user trust ranks and items

A collaborative filtering algorithm based on user trust ranks and items is proposed to improve the anti-“shilling attacks” ability. Firstly, a user relationship graph is built based on user interest similarities, rating similarities, and rating correlations. Secondly, using the relationship graph, a userrank model is proposed to calculate user trust ranks. Thirdly, the userrank values are taken as users’ weights to incorporated into the typical item-based Slope One algorithm. Finally, we experimentally evaluate our approach and compare it to Slope One. The experiment results suggest that our approach provides better recommendation than Slope One.     

Solid Model Design on the Features of Products

To research the problem of plastic art design and emulation of products with the virtual reality technology can short the product development cycle and reduce the cost. This paper discusses the information based on the product feature ,solid model with parameters, the structure and function of this system. Combined the product properties with its solid model. Proposed a method with CAD to create the model of the product based on features in the product design. Expressed its feature parameter and shape of model fully .In the case for a deceleration box the feature model has solved the problem of physical information ,geometry information and the informative process in its production management system efficiently.     

A networked sharing application system for reverse engineering

A networked sharing application system for reverse engineering is proposed. It is targeted at a wide distribution of small and medium manufacturing enterprises and the technology complexity of reverse product design. Making full use of modern information     

Realtime Collaborative Design System Based on AutoCAD

It is hard to realize the Realtime Collaborative Design due to the limitation of network bandwidth and some other reasons over Internet. A Realtime Collaborative Design System is constructed with complete distribution construction and concentrated distribution construction. Based on the research of outcome of the research group, the dynamic data format is modified and optimized, it reduces the load of network in collaborative design to meet the requirement of realtime and enhances the capacity of rapid response and stability of the system.     

Analysis of the Impact of Electric-Rate-change on Local Economy--With the Demonstration of Chongqing City

Analyses impact of China electric market changes on electric rate is analysed.Itispoinfed out that with the change of the conditions of China electric market,the electric rate should not be priced only with the considering of the supply side's cost,and that it will be more important to consider the possible reaction of the demand side's demand to the change of electric rate. the indexes of the influences of electric rate change on local economy are put forw ard, such as rate of electric cost to product value, price rising rate. The demonstrate impact of electric rate's possible change on local economy is calculated with the data of Chongqing City, 2000.     

Metadata prefetching based on 3 gram model and datamining technology

An efficient and accurate metadata oriented prefetching scheme is critical for achieving the best metadata service performance in large distributed storage systems. Most previously developed algorithms, however, do not consider the characteristics of metadata, such as small size. In light of this issue, we presented a 3 gram based model and datamining technique to use the traces of metadata accessing to prefetch groups of users’ future metadata operations. By using large trace driven simulations in which our new prefetching scheme was adopted, it is shown that the hit rate for metadata access extracted from the traces can be increased by up to 3.9% and 16 % compared with NEXUS and least recently used(LRU), respectively.     

Testing of a six axis computer numberical control abrasive belt grinding machine based on free form surfaces

A highly efficient precision grinding method was proposed for the development of typical free form surfaces such as turbine blades. A six axis simultaneous grinding and polishing machine was created. The machine can polish free form surfaces with abrasive belt grinding technology by computer numberical control(CNC). The key techniques to develop this new grinding machine are presented in detail, including multiple axes rotary spindle grinding head, NC grinding computer aided software, cooling, a scrap removal device, and other features. The experiments of grinding and polishing turbine blades were performed based on different parameters. This research provided sufficient data to confirm reasonable belt grinding and polishing parameters.      

A controller area network based electric vehicle drive system design

To solve the key problems of the electric drive system, a controller area network(CAN) based electric drive system for electric vehicles was designed. The system was composed of two parts: a CAN communication module and a motor control module. The newest transceiver (TJA1040) and a stand alone CAN controller were used during the design of the CAN communication module, and anti jamming measures were employed to guarantee communication stability. The fuzzy vector control method and direct speed control were applied to realize highly robust control functions. This system has high compatibility. It can be installed in electric vehicles as an independent module and be extended through CAN Bus.      

Dynamic Data Exchange for Collaborative Design Based on Internet

The dynamic data exchange is the key to the realization of the collaborative design based on Internet. The features of data for collaborative design based on Internet are analyzed. The data transformation, the data transmission and the data transaction of collaborative design based on Internet are researched. The system configuration and organization mode of dynamic data exchange for collaborative design Internet-based are developed, in which, STEP serves as the product data exchange standard, and ORACLE is the kernel database of the system, so that each of the CAD systems can synchronously access the ORACLE database, share and exchange the design information. The STEP-ORACLE serves as the organizing mode of dynamic data exchange for the collaborative design based on Internet, which realizes the real-time exchange and consistency of the dynamic data between the different platforms and CAD systems.     

Research on Cooperative Design Network Security Based on IP-VPN

As the important method and instrument of agile manufacture,the technology of distributed collaborative design and manufacturing has become the hotspot of manufacturing. The basic concept and key technologies of IP_VPN are introduced in this paper,and a collaborative design network model based on IP_VPN is presented. Distributed collaborative design is a multi_user,multitask involved system, which is consisted of lots of collaborative processs,so the network security is the key of distributed collaborative design. We research on the security of collaborative design network based on IP_VPN, hence get a conclusion:we can construct an economical?practical and secure collaborative design network system by the application of data encryption,user authentication and access control based on the role,etc.     

Extracting a fetal electrocardiogram based on independent component analysis

Based on the basic generation model for the independent component analysis (ICA) and the fixed point FastICA algorithm using negentropy, three observed signals containing maternal electrocardiogram (MECG) and fetal electrocardiogram (FECG) components obtained from abdomen of a pregnant woman are successfully separated by using the FastICA algorithm with progressive orthogonalization, and the FECG is extracted. By invoking the wavelet de noising program in Matlab, the extracted FECG is decomposed to 8 levels with db2 wavelet to obtain the default soft threshold for de noising. The results show that the FastICA algorithm with progressive orthogonalization performed fast convergence. The three source components were extracted with only seven, three, and two iterations, respectively. The noise in the extracted FECG can be eliminated using wavelet de noising.     

System design on grating light valve micro electro mechanical systems optical switch

Using a computer, the structure of a grating light valve (GLV) was simulated based on analysis of optics characteristic of a GLV. Driven by the electrostatic force, the GLV has high optical efficiency and high switching speed. These traits were used to design a 1×2 micro electro mechanical systems (MEMS) optical switch in order to improve upon the traditional MEMS optical switch’s shortcomings, such as easy wear, slow switching times, and short switching lives. The simulation experiment using CoventorWare shows the first order diffraction efficiency achieves 50% and the switching time is at microsecond level when the 1.55 μm light wave length is in normal incidence and the given parameters of GLV are assigned.     

Sub pixel corner detection of tessellated picture based on camera calibration

The traditional small univalue segment assimilating nucleus (SUSAN) operator may confuse the corner and the edge. An improved SUSAN sub pixel operator with high speed and high position accuracy was proposed. According to the characteristics of the SUSAN template, the gray symmetry degree was defined to distinguish the corner from the edge. Sobel operator and gray square centrobaric arithmetic were synthesized with the improved SUSAN operator in sub pixel corner detection. In the camera calibration experiments, this method proved to be rapid and efficient, and the improved operator’s average re projection error was less than 0.2 pixels.