An Empirical Study of the Effectiveness of 'Forcing Diversity' Based on a Large Population of Diverse Programs

Use of diverse software components is a viable defence against common-mode failures in redundant softwarebased systems. Various forms of "Diversity-Seeking Decisions" (“DSDs”) can be applied to the process of developing, or procuring, redundant components, to improve the chances of the resulting components not failing on the same demands. An open question is how effective these decisions, and their combinations, are for achieving large enough reliability gains. Using a large population of software programs, we studied experimentally the effectiveness of specific "DSDs" (and their combinations) mandating differences between redundant components. Some of these combinations produced much better improvements in system probability of failure per demand (PFD) than "uncontrolled" diversity did. Yet, our findings suggest that the gains from such "DSDs" vary significantly between them and between the application problems studied. The relationship between DSDs and system PFD is complex and does not allow for simple universal rules (e.g. "the more diversity the better") to apply

Report from GI-Dagstuhl Seminar 16394: Software Performance Engineering in the DevOps World

This report documents the program and the outcomes of GI-Dagstuhl Seminar 16394 "Software Performance Engineering in the DevOps World". The seminar addressed the problem of performance-aware DevOps. Both, DevOps and performance engineering have been growing trends over the past one to two years, in no small part due to the rise in importance of identifying performance anomalies in the operations (Ops) of cloud and big data systems and feeding these back to the development (Dev). However, so far, the research community has treated software engineering, performance engineering, and cloud computing mostly as individual research areas. We aimed to identify cross-community collaboration, and to set the path for long-lasting collaborations towards performance-aware DevOps. The main goal of the seminar was to bring together young researchers (PhD students in a later stage of their PhD, as well as PostDocs or Junior Professors) in the areas of (i) software engineering, (ii) performance engineering, and (iii) cloud computing and big data to present their current research projects, to exchange experience and expertise, to discuss research challenges, and to develop ideas for future collaborations

Assessment team report on flight-critical systems research at NASA Langley Research Center

The quality, coverage, and distribution of effort of the flight-critical systems research program at NASA Langley Research Center was assessed. Within the scope of the Assessment Team's review, the research program was found to be very sound. All tasks under the current research program were at least partially addressing the industry needs. General recommendations made were to expand the program resources to provide additional coverage of high priority industry needs, including operations and maintenance, and to focus the program on an actual hardware and software system that is under development

Mitigation of H.264 and H.265 Video Compression for Reliable PRNU Estimation

The photo-response non-uniformity (PRNU) is a distinctive image sensor characteristic, and an imaging device inadvertently introduces its sensor's PRNU into all media it captures. Therefore, the PRNU can be regarded as a camera fingerprint and used for source attribution. The imaging pipeline in a camera, however, involves various processing steps that are detrimental to PRNU estimation. In the context of photographic images, these challenges are successfully addressed and the method for estimating a sensor's PRNU pattern is well established. However, various additional challenges related to generation of videos remain largely untackled. With this perspective, this work introduces methods to mitigate disruptive effects of widely deployed H.264 and H.265 video compression standards on PRNU estimation. Our approach involves an intervention in the decoding process to eliminate a filtering procedure applied at the decoder to reduce blockiness. It also utilizes decoding parameters to develop a weighting scheme and adjust the contribution of video frames at the macroblock level to PRNU estimation process. Results obtained on videos captured by 28 cameras show that our approach increases the PRNU matching metric up to more than five times over the conventional estimation method tailored for photos

Evaluation of e-Government information systems Agility: a Method and Case study

Development of e-government evaluation frameworks began around 2000s. Most of the developed approaches are technologically driven in which they focus on the “E” rather than the “Government”. Moreover, they tend to evaluate tangible measures (such as costs, benefits, etc.) and neglects important intangible measures (such as agility, sustainability, etc.). The state of the art tells that the evaluation of agility within e-government has been proved to be important but complex. However, the importance is due to the increasing need for governments to justify investments, assess impacts and monitor progress in the ever-changing environment. On the other side, the complexity comes with the concept’s multi-disciplinary, the inherited difficulty when quantifying its –intangible dimensions, and developing appropriate evaluative parameters and metrics. Based on that, our paper addresses all these considerations through a practical method for agility evaluation. This method is originally applied to a real case study of e-Algeria project as part of the review of 10 years since its launch in 2013. The objective is to evaluate the agility of TAWASSOL framework that is designed to be one-stop-shop for government services. As far as results of valuation showed low degrees of agility -in both FO (Front Office) side and BO (Back office) side, improvements are recommended for the government heads to improve the overall agility of the framework

TRACKING THE 'LIFE CYCLE TRAJECTORY': METRICS AND MEASURES FOR CONTROLLING PRODUCTIVITY OF COMPUTER AIDED SOFTWARE ENGINEERING (CASE) DEVELOPMENT

This paper proposes a new vision for the measurement and management of development productivity related to computer aided software engineering (CASE) technology. We propose that productivity be monitored and controlled in each phase of software development life cycle, a measurement approach we have termed life cycle trajectory measurement. Recent advances in CASE technology that make low cost automated measurement possible have made it feasible to collect life cycle trajectory measures. We suggest that current approaches for productivity management involve the use of static metrics that are available only at the beginning and end of the project. Yet the depth of the insights needed to make proactive adjustments in the software development process requires monitoring the range of activities across the entire software development life cycle. This can only be accomplished with metrics that can measure performance parameters in each phase of the life cycle. We develop metrics that have the ability to measure and estimate software outputs from each intermediate phase of the development life cycle. These metrics are based on a count of the objects and modules that are used as building blocks for application development in repository object-based CASE environments. The viability of such object-based metrics for life cycle trajectory measurement has been empirically tested for the software construction phase using project data generated in Integrated CASE development environments.Information Systems Working Papers Serie

Quantitative Methods in Object-Oriented Software Engineering

This paper includes a brief description of the author’s doctoral research work in Quantitative Methods applied to the Object-Oriented Software Engineering field. Previous, current and future research work are outlined. An overview of related work is also included

JPL bibliography 39-12 - Prerelease for December 1970

Bibliography of technical reports on scientific and engineering studies, December 197