Reliability Analysis of Component-Based Systems with Multiple Failure Modes

This paper presents a novel approach to the reliability modeling and analysis of a component-based system that allows dealing with multiple failure modes and studying the error propagation among components. The proposed model permits to specify the components attitude to produce, propagate, transform or mask different failure modes. These component-level reliability specifications together with information about systems global structure allow precise estimation of reliability properties by means of analytical closed formulas, probabilistic modelchecking or simulation methods. To support the rapid identification of components that could heavily affect systems reliability, we also show how our modeling approach easily support the automated estimation of the system sensitivity to variations in the reliability properties of its components. The results of this analysis allow system designers and developers to identify critical components where it is worth spending additional improvement efforts

Utilización de DEVS para evaluar arquitecturas de software

En el presente trabajo se propone un modelo para la simulación de productos de software en etapa temprana del desarrollo, empleando la arquitectura. El mismo se centra en la captura de la información necesaria relacionada al modelado arquitectónico y la transformación de los conceptos capturados a elementos de un modelo de simulación. Se propone el formalismo DEVS para incorporar las ventajas de la simulación en el contexto de diseño arquitectónico, ya que, a diferencia de otras herramientas de simulación, permite mantener el modelo desacoplado del simulador, y trabajar en forma modular y jerárquica. El modelo propuesto soporta la transformación de elementos arquitectónicos a elementos de un modelo de simulación, con el objetivo de obtener información cuantitativa para evaluar la calidad de un sistema en la etapa de diseño, permitiendo tomar decisiones tempranamente.Presentado en el VII Workshop Ingeniería de Software (WIS)Red de Universidades con Carreras en Informática (RedUNCI

Utilización de DEVS para evaluar arquitecturas de software

En el presente trabajo se propone un modelo para la simulación de productos de software en etapa temprana del desarrollo, empleando la arquitectura. El mismo se centra en la captura de la información necesaria relacionada al modelado arquitectónico y la transformación de los conceptos capturados a elementos de un modelo de simulación. Se propone el formalismo DEVS para incorporar las ventajas de la simulación en el contexto de diseño arquitectónico, ya que, a diferencia de otras herramientas de simulación, permite mantener el modelo desacoplado del simulador, y trabajar en forma modular y jerárquica. El modelo propuesto soporta la transformación de elementos arquitectónicos a elementos de un modelo de simulación, con el objetivo de obtener información cuantitativa para evaluar la calidad de un sistema en la etapa de diseño, permitiendo tomar decisiones tempranamente.Presentado en el VII Workshop Ingeniería de Software (WIS)Red de Universidades con Carreras en Informática (RedUNCI

Optimal test case selection for multi-component software system

The omnipresence of software has forced upon the industry to produce efficient software in a short time. These requirements can be met by code reusability and software testing. Code reusability is achieved by developing software as components/modules rather than a single block. Software coding teams are becoming large to satiate the need of massive requirements. Large teams could work easily if software is developed in a modular fashion. It would be pointless to have software that would crash often. Testing makes the software more reliable. Modularity and reliability is the need of the day. Testing is usually carried out using test cases that target a class of software faults or a specific module. Usage of different test cases has an idiosyncratic effect on the reliability of the software system. Proposed research develops a model to determine the optimal test case policy selection that considers a modular software system with specific test cases in a stipulated testing time. The proposed model, models the failure behavior of each component using a conditional NHPP (Non-homogeneous Poisson process) and the interactions of the components by a CTMC (continuous time Markov chain). The initial number of bugs and the bug detection rate are known distributions. Dynamic programming is used as a tool in determining the optimal test case policy. The complete model is simulated using Matlab. The Markov decision process is computationally intensive but the implementation of the algorithm is meticulously optimized to eliminate repeat calculations. This has saved roughly 25-40% in processing time for different variations of the problem

A Hierarchical Framework for Estimating Heterogeneous Architecture-based Software Reliability

Problem. The composite model approach that follows a DTMC process with constant failure rate is not analytically tractable for improving its method of solution for estimating software reliability. In this case, a hierarchical approach is preferred to improve accuracy for the method of solution for estimating reliability. Very few studies have been conducted on heterogeneous architecture-based software reliability, and those that have been done use the composite model for reliability estimation. To my knowledge, no research has been done where a hierarchical approach is taken to estimate heterogeneous architecture-based software reliability. This paper explores the use and effectiveness of a hierarchical framework to estimate heterogeneous architecture-based software reliability. -- Method. Concepts of reliability and reliability prediction models for heterogeneous software architecture were surveyed. The different architectural styles were identified as batch-sequential, parallel filter, fault tolerance, and call and return. A method for evaluating these four styles solely on the basis of transition probability was proposed. Four case studies were selected from similar researches which have been done to test the effectiveness of the proposed hierarchical framework. The study assumes that the method of extracting the information about the software architecture was accurate and that the actual reliability of the systems used were free of software errors. -- Results. The percentage difference in results of the reliability estimated by the proposed hierarchical framework compared with the actual reliability was 5.12%, 11.09%, 0.82%, and 52.14% for Cases 1, 2, 3, and 4 respectively. The proposed hierarchical framework did not work for Case 4, which showed much higher values in component utilization and therefore higher interactions between components when compared with the other cases. -- Conclusions. The proposed hierarchical framework generally showed close comparison with the actual reliability of the software systems used in the case studies. However, the results obtained by the proposed hierarchical framework compared to the actual reliability were in disagreement for Case 4. This is due to the higher component interactions in Case 4 when compared with other cases and showed that there are limitations to the extent to which the proposed hierarchical framework can be applied. The reasoning for the limitations of the hierarchical approach has not been cited in any research on the subject matter. Even with the limitations, the hierarchical framework for estimating heterogeneous architecture-based software reliability can still be applied when high accuracy is not required and not too high interactions among components in the software system exist. Thesis (M.S.) -- Andrews University, College of Arts and Sciences, 201

Early stage software reliability prediction using Bayesian networks

While much work has been done in estimating software reliability, little attention is paid to predict reliability as early as at the design time. In this report, we present our initial research results of building an early stage software reliability prediction model. In Part I, we will first investigate and extract essential factors related to early stage software reliability prediction. A reliability model is then proposed which incorporates software design metrics, software architecture specification, operational profiles, software development process and environment. The model is constructed in Bayesian networks to address the existence of uncertainty underlying the available design time information. In Part II, we will validate a small portion of the proposed reliability model. We first obtain various metrics values and test results on an object oriented student project. A small model is then generated by a specific algorithm, and various experiments are done on it. The prediction results are analyzed

Biometrics system reliability evaluation method

Biometrijski sustavi ulaze u sve češću i rašireniju uporabu od 2003. godine, kada naputak o primjeni istih, u domeni uporabe u svrhu jačanja nacionalne sigurnosti, biva ugrađen u strategiju nacionalne sigurnosti EU, SAD te mnogih drugih zemalja. Motivi za primjenu biometrijskih sustava, posebno u domeni mjera nacionalne sigurnosti, često otvaraju niz pitanja iz područja povjerenja u svrhu korištenja prikupljenih podataka čime se u mnogim situacijama zadire u sferu potencijalnog kompromitiranja i narušavanja privatnosti osoba. Procesi standardizacije biometrijskih antropometrijskih sustava, kao preduvjet za povećanje povjerenja korisnika sustava, aktualni posljednjih godina, uglavnom se fokusiraju na definiranje određenih tehničkih značajki sustava bez eksplicitnog definiranja zahtjeva kvalitete funkcioniranja samih biometrijskih sustava. Pouzdanost biometrijskih sustava jedan je od temeljnih parametara za ocjenu kvalitete istih te sukladno tomu prijedlog budućeg znanstvenog istraživanja biti će utemeljen na povezivanju postojećih saznanja glede evaluacije pouzdanosti biometrijskih sustava s aspekta tehnologije sustava, okoline uporabe te korisnika sustava s ciljem definiranja metode za evaluaciju pouzdanosti utemeljenoj na ontologiji. U radu je dan pregled postojećih modela evaluacije pouzdanosti te razvijen evaluacijski model OOEPBS (otvoreni okvir za evaluaciju pouzdanosti biometrijskih sustava) utemeljen na definiranoj metodi za evaluaciju pouzdanosti biometrijskih sustava. Na temelju evaluacijskog modela OOEPBS izgrađena je ontologija čija je krovna domena biometrijska znanost sa specijalizacijom koncepata koji pokrivaju problematike evaluacije pouzdanosti biometrijskih sustava. Realizirana je također i provjera valjanosti te vrednovanje izgrađene ontologije, te su kreirane i instance koje su poslužile za testiranje okvira.The widespread usage of biometric systems is gaining momentum after 2003., when their utilization, within enforcement national security process, has been ordered and built into security strategies of the E.U., U.S.A., and many other countries. The motives for the utilization of such systems with emphasis on preserving national security, often raises a number of questions in the domain of privacy concerns regarding the potential misuse of the collected data, thus often penetrating into the sphere of potential compromising of users privacy. On the other hand, biometric system's standardization processes, which should be a prerequisite for increasing the users' confidence into the systems, predominantly focuses on defining certain technical features, without explicitly defining quality requirements. Reliability of biometric system is one of the fundamental parameters for evaluating the quality of the same, followed by the proposal of future scientific research will be based on linking existing knowledge regarding the evaluation of the reliability of biometric systems in terms, customer motivation, motivation of use of technology, the environment, usability and performance evaluation parameters with the aim of defining method for evaluating reliability based on ontology. An overview of actual evaluation models is presented in this doctoral thesis and also is developed an evaluation model OOEPBS (open framework for reliability evaluation for biometric systems) based on the reliability evaluation method for biometric systems. OOEPBS evaluation model has served for the development of the ontology with domain in biometrical science and specialization of the concepts within the reliability evaluation area. Ontology is evaluated and tested by using an open framework testing instances

Biometrics system reliability evaluation method

Biometrijski sustavi ulaze u sve češću i rašireniju uporabu od 2003. godine, kada naputak o primjeni istih, u domeni uporabe u svrhu jačanja nacionalne sigurnosti, biva ugrađen u strategiju nacionalne sigurnosti EU, SAD te mnogih drugih zemalja. Motivi za primjenu biometrijskih sustava, posebno u domeni mjera nacionalne sigurnosti, često otvaraju niz pitanja iz područja povjerenja u svrhu korištenja prikupljenih podataka čime se u mnogim situacijama zadire u sferu potencijalnog kompromitiranja i narušavanja privatnosti osoba. Procesi standardizacije biometrijskih antropometrijskih sustava, kao preduvjet za povećanje povjerenja korisnika sustava, aktualni posljednjih godina, uglavnom se fokusiraju na definiranje određenih tehničkih značajki sustava bez eksplicitnog definiranja zahtjeva kvalitete funkcioniranja samih biometrijskih sustava. Pouzdanost biometrijskih sustava jedan je od temeljnih parametara za ocjenu kvalitete istih te sukladno tomu prijedlog budućeg znanstvenog istraživanja biti će utemeljen na povezivanju postojećih saznanja glede evaluacije pouzdanosti biometrijskih sustava s aspekta tehnologije sustava, okoline uporabe te korisnika sustava s ciljem definiranja metode za evaluaciju pouzdanosti utemeljenoj na ontologiji. U radu je dan pregled postojećih modela evaluacije pouzdanosti te razvijen evaluacijski model OOEPBS (otvoreni okvir za evaluaciju pouzdanosti biometrijskih sustava) utemeljen na definiranoj metodi za evaluaciju pouzdanosti biometrijskih sustava. Na temelju evaluacijskog modela OOEPBS izgrađena je ontologija čija je krovna domena biometrijska znanost sa specijalizacijom koncepata koji pokrivaju problematike evaluacije pouzdanosti biometrijskih sustava. Realizirana je također i provjera valjanosti te vrednovanje izgrađene ontologije, te su kreirane i instance koje su poslužile za testiranje okvira.The widespread usage of biometric systems is gaining momentum after 2003., when their utilization, within enforcement national security process, has been ordered and built into security strategies of the E.U., U.S.A., and many other countries. The motives for the utilization of such systems with emphasis on preserving national security, often raises a number of questions in the domain of privacy concerns regarding the potential misuse of the collected data, thus often penetrating into the sphere of potential compromising of users privacy. On the other hand, biometric system's standardization processes, which should be a prerequisite for increasing the users' confidence into the systems, predominantly focuses on defining certain technical features, without explicitly defining quality requirements. Reliability of biometric system is one of the fundamental parameters for evaluating the quality of the same, followed by the proposal of future scientific research will be based on linking existing knowledge regarding the evaluation of the reliability of biometric systems in terms, customer motivation, motivation of use of technology, the environment, usability and performance evaluation parameters with the aim of defining method for evaluating reliability based on ontology. An overview of actual evaluation models is presented in this doctoral thesis and also is developed an evaluation model OOEPBS (open framework for reliability evaluation for biometric systems) based on the reliability evaluation method for biometric systems. OOEPBS evaluation model has served for the development of the ontology with domain in biometrical science and specialization of the concepts within the reliability evaluation area. Ontology is evaluated and tested by using an open framework testing instances