probabilities using index-count filtering are larger than those for exponential filtering. For Titan, the results are mixed, further suggesting that Titan reliability has not improved in recent years. For comparison purposes, the same filtering techniques have been applied to all flight tests shown in the tables of Appendix D, regardless of configuration. The results are presented in Table 3. Table 3. Predicted Failure Probabilities for All Configurations Filter Technic ue Sample Flight Equal Index Expon. Expon Expon Failures Vehicle Phase Weight Count F =0.99 F=0.98 F =0.97 /Total Atlas 0 0 0 0 0 0 0/7 0-1 0.1053 0.0641 0.0422 0.0273 0.0190 56/532 0-2 0.1711 0.0990 0.0555 0.0311 0.0204 91/532 0-3 0.2086 0.1261 0.0802 0.0559 0.0455 111/532 0-4 0.2143 0.1330 0.0873 0.0627 0.0511 114/532 0-5 • 0.2575 0.1671 0.1150 0.0866 0.0725 137/532 Delta 0 0 0 0 0 0 0/196 0-1. 0.0172 0.0164 0.0148 0.0110 0.0077 4/232 0-2 0.0259 0.0232 0.0201 0.0133 0.0085 6/232 0-3 0.0431 0.0279 0.0263 0.0150 0.0089 10/232 0-4 0.0431 0.0279 0.0263 0.0150 0.0089 10/232 0-5* 0.1078 0.0766 0.0740 0.0536 0.0459 25/232 Titan 0 0.0306 0.0137 0.0187 0.0281 0.0349 3/98 0-1 0.0534 0.0319 0.0351 0.0399 0.0467 18/337 0-2 0.1424 0.0771 0.0719 0.0662 0.0750 48/337 0-3 0.1632 0.0924 0.0830 0.0711 0.0770 55/337 0-4 0.1662 0.0942 0.0840 0.0712 0.0771 56/337 0-5· 0.1958· 0.1369 0.1326 0.1277 0.1346 66/337 • Includes response mode 'NA' .A comparison of Table 2 and Table 3 shows that in most cases, but not all, exponential filtering produces failure probabilities for the representative configuration samples that are smaller than the corresponding probabilities for the all-configuration samples. The fact that most differences between corresponding samples are relatively small attests to the effectiveness of the exponential filter in down-weighting early launch failures. This is not the case for equal weighting of tests, where the predicted failure probabilities based on all configurations are up to 3.6 times as large. With respect to- the weighting of missile and space-vehicle performance data, RTI favors an exponential filter over either the equal-weight or index-count filters. Weighting percentages for the three filters are given in Table 4 for sample sizes of 4 to 1,000. Except for small samples, the percentages produced by equal weighting place too much emphasis on old data, thus failing to account for the learning process and 9/10/96 18 RTI
Vision Description (EN)
Technical analysis page featuring Table 6 with failure probabilities for Atlas, Delta, and Titan launch vehicles across flight phases 0-1 and 0-2. The narrative below the table discusses the relative effectiveness of exponential, equal-weight, and index-count filtering techniques applied to launch failure data. Section 5.2 begins with discussion of Relative and Absolute Probabilities for Response Modes. The page contains dense technical text with mathematical comparisons of failure probability estimation methods. Footer indicates page 24, dated 9/10/96, prepared by RTI.
Descrição Vision (PT-BR)
Página de análise técnica apresentando a Tabela 6 com probabilidades de falha para veículos de lançamento Atlas, Delta e Titã em fases de voo 0-1 e 0-2. A narrativa abaixo da tabela discute a eficácia relativa de técnicas de filtragem exponencial, peso igual e contagem de índice aplicadas aos dados de falha de lançamento. A seção 5.2 começa com discussão sobre Probabilidades Relativas e Absolutas para Modos de Resposta. A página contém texto técnico denso com comparações matemáticas de métodos de estimação de probabilidade de falha. O rodapé indica página 24, datada 9/10/96, preparada pela RTI.