To accurately predict quality loss of high reliability and long‐life product in service, a dynamic quality characteristics model is established based on linear degeneration and random error. According to this model, the expectation and variance of dynamic quality characteristics can be figured out. Moreover, assuming that the quality characteristics follow the normal distribution at the initial stage, the expectation of quality loss and the life distribution of dynamic quality characteristics follow three types are derived, such as L‐type (Larger is better), S‐type (Smaller is better), and N‐type (Nominal is better). According to the discount theory of quality loss, the present value model of dynamic quality loss based on the life is derived by combining life and the present value of dynamic quality loss. Then, this model is used to evaluate the quality loss of a GaAs laser and the rationality of the model is analyzed.

中文翻译：

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考虑线性退化和随机误差的机械系统寿命质量损失预测

为了准确预测高可靠性和使用寿命长的产品在服务中的质量损失，建立了基于线性退化和随机误差的动态质量特征模型。根据该模型，可以得出动态质量特性的期望和方差。此外，假设质量特性在初始阶段服从正态分布，则推导了质量损失的期望和动态质量特性的寿命分布遵循三种类型，例如L型（越大越好），S型（越小越好）和N型（标称越好）。根据质量损失折价理论，将生命与动态质量损失的现值相结合，得出了基于寿命的动态质量损失的现值模型。然后，