The paper provided an overview of computer aided tolerance design and described the research methods of tolerance design. An example of a displacement pump was employed to analyze the angle and linear tolerance. With the application of tolerance optimization design of CAD assemblies combined with tolerance annotation and tolerance accumulation validation, the product design can be optimized and the cost can be reduced effectively.

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Abstract. With global information technology development, the era of big data is in the offing. Power industry is closely related with people's livelihood and it is necessary to introduce big data technology to improve its economy and reliability. The completion of Jiangsu Electricity Information Acquisition System and the accumulation of historical information both laid a rich foundation for the study of the electricity big data. Jiangsu Electricity Power Company has an advantage and it is necessary to take full advantage of electricity big data to carry out related researches. Based on electricity big data, research works on short-term load forecasting were carried out in this paper, which had achieved some results and made a certain contribution for the promotion of big data technology in Jiangsu Electricity Power Company.

The requirement of the welding technology is very rigid in modern shipbuilding industry. This paper firstly analyzed the different forms of welding joints and grooves in detail, then described the function of NX-based welding technology. The difference of the features of Fillet Weld and that of Welding Joint were compared in the paper. Finally, a case was employed to explain the process of feature creation.