Worst Case Reliability Prediction Based on a Prior Estimate of Residual Defects

In this paper we extend an earlier worst case bound reliability theory to derive a worst case reliability function R(t), which gives the worst case probability of surviving a further time t given an estimate of residual defects in the software N and a prior test time T. The earlier theory and its extension are presented and the paper also considers the case where there is a low probability of any defect existing in the program. For the "fractional defect" case, there can be a high probability of surviving any subsequent time t. The implications of the theory are discussed and compared with alternative reliability models

Estimating Residual Faults from Code Coverage

Many reliability prediction techniques require an estimate for the number of residual faults. In this paper, a new theory is developed for using test coverage to estimate the number of residual faults. This theory is applied to a specific example with known faults and the results agree well with the theory. The theory is used to justify the use of linear extrapolation to estimate residual faults. It is also shown that it is important to establish the amount of unreachable code in order to make a realistic residual fault estimate

Using longitudinal survival probabilities to test field vigour estimates in sugar maple (Acer saccharum Marsh.)

Tree mortality is a major force driving forest dynamics. To foresters, however, tree mortality is often considered a loss in productivity. To reduce tree mortality, silvicultural systems, such as selection cuts, aim at removing trees that are more likely to die. In order to identify trees with higher risks of mortality, field classifications are employed that assess vigour based on external characteristics of trees. We used a novel longitudinal approach for estimating survival probabilities based on ring-width measurements, initially developed by Bigler and Bugmann [Bigler, C., Bugmann, H., 2004. Predicting the time of tree death using dendrochronological data. Ecol. Appl. 14 (3), 902-914], to parameterize a survival probability model for sugar maple (Acer saccharum Marsh.) and to test whether field-assessed tree vigour classes are corroborated by survival probabilities determined from radial growth history. Data from 56 dead and 321 live sugar maples were collected in stands in western Quebec (Canada) that had undergone a selection cut ≈10 years prior to sampling. Our results showed that tree vigour established from external defects and pathological symptoms, using the classification of Boulet [Boulet, B., 2005. D

Adverse social determinats and risk for congenital anomalies

INTRODUCCIÓN: Diferentes trabajos han relacionando condiciones sociales adversas a nivel familiar y regional con resultados perinatales (mortalidad neonatal, bajo peso y prematuridad); sin embargo, pocos estudiaron el efecto de la pobreza sobre anomalías congénitas. Objetivo. Evaluar el riesgo de ocurrencia de 25 anomalías congénitas y determinantes sociales adversos según el nivel socioeconómico de la familia y de la región. POBLACIÓN Y MÉTODOS. Estudio caso-control exploratorio, en el que se utilizaron datos del Estudio Colaborativo Latinoamericano de Malformaciones Congénitas (ECLAMC). La muestra consistió en 3786 recién nacidos vivos con una única malformación y 13 344 controles, seleccionados entre 546 129 nacimientos, ocurridos en 39 hospitales de Argentina durante el período 1992-2001. Se estimaron los riesgos (OR) directos, indirectos (a través de la región de residencia) y la interacción entre el nivel socioeconómico individual y residencial para cada uno de los 25 defectos congénitos. RESULTADOS: Los defectos labio leporino con/sin paladar hendido (OR= 1,43) y comunicación interventricular (OR= 1,38) mostraron un riesgo significativamente mayor en el nivel socioeconómico más bajo. Los niveles socioeconómicos bajos se asociaron de manera significativa con una mayor frecuencia de consanguinidad parental, ancestros nativos, edad materna menor de 19 años, más de 4 embarazos, bajo número de visitas prenatales y residencia en regiones desfavorables. CONCLUSIÓN: La fisura labial con o sin paladar hendido y los defectos del tabique interventricular estuvieron asociados significativamente con un nivel socioeconómico más bajo. La falta de planificación familiar, de control prenatal y la exposición a agentes ambientales o teratógenos pueden explicar estos hallazgos.INTRODUCTION: Different studies have related familiar and regional adverse social conditions to perinatal outcome (neonatal mortality, low birth weight and prematurity); however, few studies have studied the effect of poverty on congenital anomalies. OBJECTIVE: To assess the hazard ratio of 25 congenital anomalies and adverse social determinants as per the socioeconomic level of families and regions. POPULATION AND METHODS: Exploratory, case-control study using data from the Latin-American Collaborative Study of Congenital Malformations (Estudio Colaborativo Latinoamericano de Malformaciones Congenitas, ECLAMC). The sample consisted of 3786 live newborn infants with a single malformation and 13,344 controls selected among 546,129 births occurred in 39 hospitals from Argentina in the 1992-2001 period. Both direct and indirect (residence) risks (OR) were estimated, together with the interaction between the individual and residential socioeconomic levels for each of the 25 congenital anomalies. RESULTS: Cleft lip with/without cleft palate (OR= 1.43) and ventricular septal defect (OR= 1.38) showed a significantly higher risk in the lower socioeconomic level. Low socioeconomic levels were significantly associated with a higher frequency of parental sibship (blood relationship); native descent; maternal age younger than 19 years old; more than four pregnancies; a low number of antenatal care visits; and residence in deprived regions. CONCLUSION: Cleft lip with/without cleft palate and ventricular septal defects were significantly associated with a lower socioeconomic level. Lack of family planning and antenatal care; and exposure to environmental or teratogenic agents may account for these findings.Fil: Pawluk, Mariela Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET.; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Campaña, Hebe. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET.; ArgentinaFil: Gili, Juan Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET.; ArgentinaFil: Comas, Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET.; ArgentinaFil: Gimenez, Lucas Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET.; ArgentinaFil: Villalba, María Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: Scala, Sandra C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: Poletta, Fernando Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET.; Argentina. Instituto Nacional de Genética Médica Poblacional; BrasilFil: López Camelo, Jorge Santiago. Instituto Nacional de Genética Médica Poblacional; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; Argentin

Simulation of the ductile damage during the metal forming

It was shown in this paper that the damage degree is estimated by the scalar value , that is equal to 00before plastically strain and is equal to 11at the macrocracs moment. There are two criteria that describe micro damage. The value corresponds to the generation of micro voids that couldn’t be recovered by recrystallization but do not reduce the metal strength. The value corresponds to the generation of micro voids that reduce the metal strength and material longlife. The models of metal damage accumulation during pure and alternate forming also the model of metal damage recovery under the recrystallization are developed. The speciment testing at high loading parameters gives the basic equations of the ductile damage mechanics. All of that gives the method to study ductile damage during the metal forming

Phase Transitions In Two Planar Lattice Models And Topological Defects: A Monte Carlo Study

Monte Carlo simulation has been performed in the planar P(_{2}) and P(_{4}) models to investigate the effects of the suppression of topological defects on the phase transition exhibited by these models. Suppression of the 1/2-defects on the square plaquettes in the P(_{2}) model leads to complete elimination of the phase transition observed in this model. However in the P(_{4}) model, on suppressing the single 1/2-defects on square plaquettes, the otherwise first order phase transition changes to a second order one which occurs at a higher temperature and this is due to presence of large number of 1/2-pair defects which are left within the square plaquettes. When we suppressed these charges too, complete elimination of phase transition was observed.Comment: Related work has been presented in 22 nd International Conference on Statistical Physics, STATPHYS22, IISC Bangalore, Indi

Identification of machining defects by Small Displacement Torsor and form parameterization method

In the context of product quality, the methods that can be used to estimate machining defects and predict causes of these defects are one of the important factors of a manufacturing process. The two approaches that are presented in this article are used to determine the machining defects. The first approach uses the Small Displacement Torsor (SDT) concept [BM] to determine displacement dispersions (translations and rotations) of machined surfaces. The second one, which takes into account form errors of machined surface (i.e. twist, comber, undulation), uses a geometrical model based on the modal shape's properties, namely the form parameterization method [FS1]. A case study is then carried out to analyze the machining defects of a batch of machined parts

MC/DC based estimation and detection of residual faults in PLC logic networks

A logic coverage measure related to MC/DC testing is used to estimate residual faults. The residual fault prediction method is evaluated on an industrial PLC logic example. A randomized form of MC/DC testing is used to maximize coverage growth and fault detection efficiency

Robust Dynamic Selection of Tested Modules in Software Testing for Maximizing Delivered Reliability

Software testing is aimed to improve the delivered reliability of the users. Delivered reliability is the reliability of using the software after it is delivered to the users. Usually the software consists of many modules. Thus, the delivered reliability is dependent on the operational profile which specifies how the users will use these modules as well as the defect number remaining in each module. Therefore, a good testing policy should take the operational profile into account and dynamically select tested modules according to the current state of the software during the testing process. This paper discusses how to dynamically select tested modules in order to maximize delivered reliability by formulating the selection problem as a dynamic programming problem. As the testing process is performed only once, risk must be considered during the testing process, which is described by the tester's utility function in this paper. Besides, since usually the tester has no accurate estimate of the operational profile, by employing robust optimization technique, we analysis the selection problem in the worst case, given the uncertainty set of operational profile. By numerical examples, we show the necessity of maximizing delivered reliability directly and using robust optimization technique when the tester has no clear idea of the operational profile. Moreover, it is shown that the risk averse behavior of the tester has a major influence on the delivered reliability.Comment: 19 pages, 4 figure