Demonstration of a Response Time Based Remaining Useful Life (RUL) Prediction for Software Systems

Prognostic and Health Management (PHM) has been widely applied to hardware systems in the electronics and non-electronics domains but has not been explored for software. While software does not decay over time, it can degrade over release cycles. Software health management is confined to diagnostic assessments that identify problems, whereas prognostic assessment potentially indicates when in the future a problem will become detrimental. Relevant research areas such as software defect prediction, software reliability prediction, predictive maintenance of software, software degradation, and software performance prediction, exist, but all of these represent diagnostic models built upon historical data, none of which can predict an RUL for software. This paper addresses the application of PHM concepts to software systems for fault predictions and RUL estimation. Specifically, this paper addresses how PHM can be used to make decisions for software systems such as version update and upgrade, module changes, system reengineering, rejuvenation, maintenance scheduling, budgeting, and total abandonment. This paper presents a method to prognostically and continuously predict the RUL of a software system based on usage parameters (e.g., the numbers and categories of releases) and performance parameters (e.g., response time). The model developed has been validated by comparing actual data, with the results that were generated by predictive models. Statistical validation (regression validation, and k-fold cross validation) has also been carried out. A case study, based on publicly available data for the Bugzilla application is presented. This case study demonstrates that PHM concepts can be applied to software systems and RUL can be calculated to make system management decisions.Comment: This research methodology has opened up new and practical applications in the software domain. In the coming decades, we can expect a significant amount of attention and practical implementation in this area worldwid

Analyzing the Influence of Processor Speed and Clock Speed on Remaining Useful Life Estimation of Software Systems

Prognostics and Health Management (PHM) is a discipline focused on predicting the point at which systems or components will cease to perform as intended, typically measured as Remaining Useful Life (RUL). RUL serves as a vital decision-making tool for contingency planning, guiding the timing and nature of system maintenance. Historically, PHM has primarily been applied to hardware systems, with its application to software only recently explored. In a recent study we introduced a methodology and demonstrated how changes in software can impact the RUL of software. However, in practical software development, real-time performance is also influenced by various environmental attributes, including operating systems, clock speed, processor performance, RAM, machine core count and others. This research extends the analysis to assess how changes in environmental attributes, such as operating system and clock speed, affect RUL estimation in software. Findings are rigorously validated using real performance data from controlled test beds and compared with predictive model-generated data. Statistical validation, including regression analysis, supports the credibility of the results. The controlled test bed environment replicates and validates faults from real applications, ensuring a standardized assessment platform. This exploration yields actionable knowledge for software maintenance and optimization strategies, addressing a significant gap in the field of software health management

Understanding and Modeling the Life-Cycle Cost Tradeoffs Associated with the Procurement of Open Systems

Acquisition Research Program Sponsored Report SeriesSponsored Acquisition Research & Technical ReportsOpenness (of a system or architecture), though intuitively understood, remains difficult to quantify in terms of its value. Although commonly associated with cost avoidance, system openness can also increase costs. Previous efforts have relied on highly qualitative system analyses, with the results often articulated as an intangible “openness score”, for determining which of multiple system implementations is more open. Such approaches do not provide enough information to make a business case or understand the conditions under which life-cycle cost avoidance can be maximized (or whether there even is cost avoidance). This report presents a multivariate model that quantifies the relationship between system openness and life-cycle cost. A case study that evaluates the Acoustic Rapid COTS Insertion (A-RCI) Sonar System is provided.Approved for public release; distribution is unlimited.Approved for public release; distribution is unlimited

International Journal of Prognostics and Health Management, ISSN 2153-2648, 2016 008 PHM-Based Wind Turbine Maintenance Optimization Using Real Options

A simulation-based real options analysis (ROA) approach is used to determine the optimum predictive maintenance opportunity for a wind turbine with a remaining useful life (RUL) prediction. When an RUL is predicted for a subsystem in a single turbine using PHM, a predictive maintenance option is triggered that the decision-maker has the flexibility to decide if and when to exercise before the subsystem or turbine fails. The predictive maintenance value paths are simulated by considering the uncertainties in the RUL prediction and wind speed (that govern the turbine’s revenue earning potential). By valuating a series of European options expiring on all possible predictive maintenance opportunities, a series of option values can be obtained, and the optimum predictive maintenance opportunity can be determined. A case study is presented in which the ROA approach is applied to a single turbine

Development of Red Flags Index for Early Referral of Adults with Symptoms and Signs Suggestive of Crohn's Disease: An IOIBD Initiative

International audience; BACKGROUND AND AIMS:Diagnostic delay is frequent in patients with Crohn's disease (CD). We developed a tool to predict early diagnosis.METHODS:A systematic literature review and 12 CD specialists identified 'Red Flags', i.e. symptoms or signs suggestive of CD. A 21-item questionnaire was administered to 36 healthy subjects, 80 patients with irritable bowel syndrome (non-CD group) and 85 patients with recently diagnosed (<18 months) CD. Patients with CD were asked to recall symptoms and signs they experienced during the 12 months before diagnosis. Multiple logistic regression analyses selected and weighted independent items to construct the Red Flags index. A receiver operating characteristic curve was used to assess the threshold that discriminated CD from non-CD. Association with the Red Flags index relative to this threshold was expressed as the odds ratios (OR).RESULTS:Two hundred and one subjects, CD and non-CD, answered the questionnaire. The multivariate analysis identified eight items independently associated with a diagnosis of CD. A minimum Red Flags index value of 8 was highly predictive of CD diagnosis with sensitivity and specificity bootstrap estimates of 0.94 (95% confidence interval 0.88-0.99) and 0.94 (0.90-0.97), respectively. Positive and negative likelihood ratios were 15.1 (9.3-33.6) and 0.066 (0.013-0.125), respectively. The association between CD diagnosis and a Red Flags index value of ≥8 corresponds to an OR of 290 (p < 0.0001).CONCLUSIONS:The Red Flags index using early symptoms and signs has high predictive value for the diagnosis of CD. These results need prospective validation prior to introduction into clinical practice

Association of Biomarker Cutoffs and Endoscopic Outcomes in Crohn's Disease: A Post Hoc Analysis From the CALM Study

Abstract Background CALM was a randomized phase 3 trial in patients with Crohn's disease (CD) that demonstrated improved endoscopic outcomes when treatment was escalated based on cutoffs for inflammatory biomarkers, fecal calprotectin (FC), C-reactive protein (CRP), and CD Activity Index (CDAI) remission vs CDAI response alone. The purpose of this post hoc analysis of CALM was to identify drivers of treatment escalation and evaluate the association between biomarker cutoff concentrations and endoscopic end points. Methods The proportion of patients achieving CD Endoscopic Index of Severity (CDEIS) &lt;4 and no deep ulcers 48 weeks after randomization was evaluated according to CRP &lt;5 mg/L or ≥5 mg/L and FC &lt;250 μg/g or ≥250 μg/g. Subgroup analyses were performed according to disease location, and sensitivity analyses were conducted in patients with elevated CRP and/or FC at baseline. The association between endoscopic end points and biomarker cutoffs was performed using χ 2 test. Results The proportion of patients who achieved the primary end point CDEIS &lt;4 and no deep ulcers was significantly greater for those with FC &lt;250 µg/g (74%; P &lt; 0.001), with an additive effect for CRP &lt;5 mg/L. The association of FC &lt;250 µg/g with improved endoscopic outcomes was independent of disease location, although the greatest association was observed for ileocolonic disease. Fecal calprotectin &lt;250 µg/g, CRP &lt;5 mg/L, and CDAI &lt;150 gave a sensitivity/specificity of 72%/63% and positive/negative predictive values of 86%/42% for CDEIS &lt;4 and no deep ulcers 48 weeks after randomization. Conclusion This post hoc analysis of CALM demonstrated that a cutoff of FC &lt;250 µg/g is a useful surrogate marker for mucosal healing in CD

Elevated A20 promotes TNF-induced and RIPK1-dependent intestinal epithelial cell death

Intestinal epithelial cell (IEC) death is a common feature of inflammatory bowel disease (IBD) that triggers inflammation by compromising barrier integrity. In many patients with IBD, epithelial damage and inflammation are TNF-dependent. Elevated TNF production in IBD is accompanied by increased expression of the TNFAIP3 gene, which encodes A20, a negative feedback regulator of NF-κB. A20 in intestinal epithelium from patients with IBD coincided with the presence of cleaved caspase-3, and A20 transgenic (Tg) mice, in which A20 is expressed from an IEC-specific promoter, were highly susceptible to TNF-induced IEC death, intestinal damage, and shock. A20-expressing intestinal organoids were also susceptible to TNF-induced death, demonstrating that enhanced TNF-induced apoptosis was a cell-autonomous property of A20. This effect was dependent on Receptor Interacting Protein Kinase 1 (RIPK1) activity, and A20 was found to associate with the Ripoptosome complex, potentiating its ability to activate caspase-8. A20-potentiated RIPK1-dependent apoptosis did not require the A20 deubiquitinase (DUB) domain and zinc finger 4 (ZnF4), which mediate NF-κB inhibition in fibroblasts, but was strictly dependent on ZnF7 and A20 dimerization. We suggest that A20 dimers bind linear ubiquitin to stabilize the Ripoptosome and potentiate its apoptosis-inducing activity