334,801 research outputs found
CARES/Life Software for Designing More Reliable Ceramic Parts
Products made from advanced ceramics show great promise for revolutionizing aerospace and terrestrial propulsion, and power generation. However, ceramic components are difficult to design because brittle materials in general have widely varying strength values. The CAPES/Life software eases this task by providing a tool to optimize the design and manufacture of brittle material components using probabilistic reliability analysis techniques. Probabilistic component design involves predicting the probability of failure for a thermomechanically loaded component from specimen rupture data. Typically, these experiments are performed using many simple geometry flexural or tensile test specimens. A static, dynamic, or cyclic load is applied to each specimen until fracture. Statistical strength and SCG (fatigue) parameters are then determined from these data. Using these parameters and the results obtained from a finite element analysis, the time-dependent reliability for a complex component geometry and loading is then predicted. Appropriate design changes are made until an acceptable probability of failure has been reached
Measuring the BDARX architecture by agent oriented system a case study
Distributed systems are progressively designed as multi-agent systems that are helpful in designing high strength complex industrial software. Recently, distributed systems cooperative applications are openly access, dynamic and large scales. Nowadays, it hardly seems necessary to emphasis on the potential of decentralized software solutions. This is because the main benefit lies in the distributed nature of information, resources and action. On the other hand, the progression in multi agent systems creates new challenges to the traditional methodologies of fault-tolerance that typically relies on centralized and offline solution. Research on multi-agent systems had gained attention for designing software that operates in distributed and open environments, such as the Internet. DARX (Dynamic Agent Replication eXtension) is one of the architecture which aimed at building reliable software that would prove to be both flexible and scalable and also aimed to provide adaptive fault tolerance by using dynamic replication methodologies. Therefore, the enhancement of DARX known as BDARX can provide dynamic solution of byzantine faults for the agent based systems that embedded DARX. The BDARX architecture improves the fault tolerance ability of multi-agent systems in long run and strengthens the software to be more robust against such arbitrary faults. The BDARX provide the solution for the Byzantine fault tolerance in DARX by making replicas on the both sides of communication agents by using BFT protocol for agent systems instead of making replicas only on server end and assuming client as failure free. This paper shows that the dynamic behaviour of agents avoid us from making discrimination between server and client replicas
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A Survey of Software Fault Tolerance Techniques
This report examines the state of the field of software fault tolerance. Terminology, techniques for building reliable systems, and fault tolerance are discussed. While a scientific consensus on the measurement of software reliability has not been reached, software systems are sufficiently pervasive that “software“ components of larger systems must be reliable, since dependence is placed on them. Fault tolerant systems utilize redundant components to mitigate the effects of component failures, and thus create a system which is more reliable than a single component. This idea can be applied to software systems as well. Several techniques for designing fault tolerant software systems are discussed and assessed qualitatively, where "software fault" refers to what is more commonly known as a bug. The assumptions, relative merits, available experimental results, and implementation experience are discussed for each technique. This leads us to some conclusions about the state of the field
An Intelligent Auxiliary Vacuum Brake System
The purpose of this paper focuses on designing an intelligent, compact, reliable, and robust auxiliary vacuum brake system (VBS) with Kalman filter and self-diagnosis scheme. All of the circuit elements in the designed system are integrated into one programmable system-on-chip (PSoC) with entire computational algorithms implemented by software. In this system, three main goals are achieved: (a) Kalman filter and hysteresis controller algorithms are employed within PSoC chip by software to surpass the noises and disturbances from hostile surrounding in a vehicle. (b) Self-diagnosis scheme is employed to identify any breakdown element of the auxiliary vacuum brake system. (c) Power MOSFET is utilized to implement PWM pump control and compared with relay control. More accurate vacuum pressure control has been accomplished as well as power energy saving. In the end, a prototype has been built and tested to confirm all of the performances claimed above
Evaluation of the Design Metric to Reduce the Number of Defects in Software Development
Software design is one of the most important and key activities in the system
development life cycle (SDLC) phase that ensures the quality of software.
Different key areas of design are very vital to be taken into consideration
while designing software. Software design describes how the software system is
decomposed and managed in smaller components. Object-oriented (OO) paradigm has
facilitated software industry with more reliable and manageable software and
its design. The quality of the software design can be measured through
different metrics such as Chidamber and Kemerer (CK) design metrics, Mood
Metrics & Lorenz and Kidd metrics. CK metrics is one of the oldest and most
reliable metrics among all metrics available to software industry to evaluate
OO design. This paper presents an evaluation of CK metrics to propose an
improved CK design metrics values to reduce the defects during software design
phase in software. This paper will also describe that whether a significant
effect of any CK design metrics exists on total number of defects per module or
not. This is achieved by conducting survey in two software development
companies.Comment: 9 Page
A study of software standards used in the avionics industry
Within the past decade, software has become an increasingly common element in computing systems. In particular, the role of software used in the aerospace industry, especially in life- or safety-critical applications, is rapidly expanding. This intensifies the need to use effective techniques for achieving and verifying the reliability of avionics software. Although certain software development processes and techniques are mandated by government regulating agencies, no one methodology has been shown to consistently produce reliable software. The knowledge base for designing reliable software simply has not reached the maturity of its hardware counterpart. In an effort to increase our understanding of software, the Langley Research Center conducted a series of experiments over 15 years with the goal of understanding why and how software fails. As part of this program, the effectiveness of current industry standards for the development of avionics is being investigated. This study involves the generation of a controlled environment to conduct scientific experiments on software processes
Technical Report on Deploying a highly secured OpenStack Cloud Infrastructure using BradStack as a Case Study
Cloud computing has emerged as a popular paradigm and an attractive model for
providing a reliable distributed computing model.it is increasing attracting
huge attention both in academic research and industrial initiatives. Cloud
deployments are paramount for institution and organizations of all scales. The
availability of a flexible, free open source cloud platform designed with no
propriety software and the ability of its integration with legacy systems and
third-party applications are fundamental. Open stack is a free and opensource
software released under the terms of Apache license with a fragmented and
distributed architecture making it highly flexible. This project was initiated
and aimed at designing a secured cloud infrastructure called BradStack, which
is built on OpenStack in the Computing Laboratory at the University of
Bradford. In this report, we present and discuss the steps required in
deploying a secured BradStack Multi-node cloud infrastructure and conducting
Penetration testing on OpenStack Services to validate the effectiveness of the
security controls on the BradStack platform. This report serves as a practical
guideline, focusing on security and practical infrastructure related issues. It
also serves as a reference for institutions looking at the possibilities of
implementing a secured cloud solution.Comment: 38 pages, 19 figures
Integrating Adaptation Mechanisms Using Control Theory Centric Architecture Models: A Case Study
International audienceControl theory provides solid foundations for developing reliable and scalable feedback control for software systems. Although, feedback controllers have been acknowledged to efficiently solve common classes of problems, their adoption by state-of-the-art approaches for designing self-adaptation in legacy software systems remains limited and at best consists in ad hoc integrations, which are usually engineered manually. In this paper, we revisit the Znn.com case study and we present an alternative implementation based on classical feedback controllers. We show how these controllers can be easily integrated into software systems through control theory centric architecture models and domain-specific modeling support. We also provide an assessment of the resulting properties, quality attributes and limitations
Issues for Evaluating Reliability in Software Architectures
Currently, the requirements of Business sector promote more and more complex Information Systems. Reliability is one of the quality characteristics widely expected by users and developers. This characteristic is architectural by nature since it can be directly promoted by software architecture. This relation determines the importance of designing architectures that guarantee reliable systems. This article presents a research in progress whose objective is developing an architectural evaluation method based on Reliability. The first step considered for designing the method included: the construction of a Conceptual Model, a model to specify the architectural quality based on Reliability (Utility Tree), a set of scenarios associated to this characteristic. The first model allows identifying the concepts inherent to Reliability and their relationships; the second one covers all quality features related to Reliability in order to specify it; and the scenarios guide the software architect for anticipating context stimulus and evaluating the architectural responses
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