Research On Optimal Truncation Sequential Test Without Replacemen

Sampling and inspection of products with high-reliability and long-life test characteristics,such as the storage life of missiles and the service life of aircraft black boxes,as the test time for this type of product is very long,the test costs are very high,how to improve test efficiency and reduce test cost is a key problem in the designs of sampling test.Sequential inspection uses a “try-it、 see-it” test strategy,which uses the process information of the test,so it can significantly reduce the expected test sample size or expected test time,hence they can reduce the test costs significantly.For the reliability sampling test of exponentially distributed metrology-type products,the current international and national standards such as International Standard IEC61124,American National Standard MIL-HDBK-781 A,Russian National Standard GOST R 27.402,as well as most of the literature studies are the truncated sequential test scheme with substitution.In fact,for high-reliability and long-life life type products,when the truncated sample size of a sequential test is small,choose to put all the products into the test at once before the test starts,will be able to greatly reduce the natural calendar time of product.How to design the optimal truncated sequential tests without substitution,this is the problem studied in this paper.The main work of the thesis is as follows.1)An truncated sequential test scheme without substitution based on the optimal expected natural calendar timeIn order to reduce the cost of sampling inspection of products with high-reliability and long-life test characteristics,this paper study the truncated sequential test without substitution based on the optimal expected natural calendar time.A theory and definition of truncated sequential test without substitution based on the optimal expected natural calendar time is established.The calculation expressions of key statistical feature indexes such as the type I and type II error probability and expected natural calendar time.Sample space sorting method(SSSM)has been established to solve the truncated sequential test without substitution based on the optimal expected test time.Through comparing with the international standard IEC61124 the results show that,the new test scheme can simultaneously save nearly 80% of the synthesis expected natural calendar test time(SECT)with the probability of Type I and Type II errors under tight control.In addition,the new scheme also reduces the SECT by about 70%,compared with the truncated sequential optimal test scheme with substitution.The plans established in this paper significantly reduces the SECT of the test,thus significantly saving the test cost for products with high-reliability and long-life test characteristics.2)An truncated sequential test scheme without substitution based on the optimal expected test costIn order to further reduce the cost of sampling and inspection of exponentially distributed metrology-type products,through the analysis of the test cost components of the product to be inspected in the test process,the test cost model of the sequential inspection process is constructed,and the truncation sequential test without substitution based on the optimal expected test cost is studied.On this basis,the theory and definition of the truncated sequential test based on the optimal expected test cost,the expressions for calculating the statistical characteristics such as the expected number of failures and the expected test cost are given.Sample space sorting method(SSSM)has been established to solve the truncated sequential test without substitution based on the optimal expected test cost.Through compared with the international standard IEC61124 the results show that the new scheme can reduce the synthesis expected test cost(SETC)by as much as 62.49% under the condition that the probability of making two types of errors is strictly controlled.Through compared with the GOST R 27.402,the results show that,the new test plans can save by up to 58.52% of the SETC.In addition,as the cost composition ratio decreases,the percentage of its expected test cost savings tends to increase.