Inferring Temporal Behaviours Through Kernel Tracing

In order to provide reliable system support for real-time applications, it is often important to be able to collect statistics about the tasks temporal behaviours (in terms of execution times and inter-arrival times). Such statistics can, for example, be used to provide a-priori schedulability guarantees, or to perform some kind of on-line adaptation of the scheduling parameters (adaptive scheduling, or feedback scheduling). This work shows how the Linux kernel allows to collect such statistics by using an internal function tracer called Ftrace. Based on this feature, tools can be developed to evaluate the real-time performance of a system or an application, to debug real-time applications, and/or to infer the temporal properties (for example, periodicity) of tasks running in the system

Analysis, optimization, FE simulation of micro-cutting processes and integration between Machining and Additive Manufacturing.

La seguente Tesi di Dottorato riguarda i processi di Micro-Machining (MM) applicati su materiali ottenuti per fabbricazione additiva. I processi MM sono un insieme di tecnologie di produzione utilizzate per fabbricare componenti o realizzare features di piccole dimensioni. In generale, i processi di taglio sono caratterizzati da un'interazione meccanica tra un pezzo e un utensile che avviene lungo una determinata traiettoria. Il contatto determina una rottura del materiale lungo un percorso definito, ottenendo diverse forme del pezzo. Più precisamente, la denominazione di microlavorazione indica solo le lavorazioni di taglio eseguite utilizzando un utensile di diametro inferiore a 1 mm. La riduzione della scala dimensionale del processo introduce alcune criticità non presenti negli analoghi processi su scala convenzionale, come l'effetto dimensionale, la formazione di bave, la rapida usura dell'utensile, le forze di taglio superiori alle attese e l'eccentricità del moto dell'utensile. Negli ultimi decenni, diversi ricercatori hanno affrontato problemi relativi alla microlavorazione, ma pochi di loro si sono concentrati sulla lavorabilità dei materiali prodotti per Additive Manufacturing (AM). L’AM è un insieme di processi di fabbricazione strato per strato che possono essere impiegati con successo utilizzando polimeri, ceramica e metalli. L'AM dei metalli si sta rapidamente diffondendo nella produzione industriale trovando applicazioni in diversi rami, come l'industria aerospaziale e biomedica. D’altro canto, la qualità del prodotto finale non è comparabile con gli standard ottenibili mediante i metodi convenzionali di rimozione del materiale. Lo svantaggio principale dei componenti realizzati mediante AM è la bassa qualità della finitura superficiale e l'elevata rugosità; pertanto, sono solitamente necessari ulteriori trattamenti superficiali post-processo per adeguare le superfici del prodotto ai requisiti di integrità superficiale. L'integrazione tra le due tecnologie manifatturiere offre opportunità rilevanti, ma la necessità di ulteriori studi e indagini è evidenziata dalla mancanza di pubblicazioni su questo argomento. Questa ricerca mira ad esplorare diversi problemi connessi alla microlavorazione di leghe metalliche prodotte mediante AM. Le prove sperimentali sono state eseguite utilizzando il centro di lavoro ultrapreciso a 5 assi “KERN Pyramid Nano”, mentre i campioni AM sono stati forniti da aziende e gruppi di ricerca. L'attrezzatura sperimentale è stata predisposta per eseguire la micro-fresatura e per monitorare il processo in linea misurando la forza di taglio. Il comportamento di rimozione del materiale è stato studiato e descritto per mezzo di modelli analitici e simulazioni FEM. I metodi FE sono stati utilizzati anche per eseguire un confronto tra le forze di taglio previste e i carichi sperimentali, con lo scopo finale di affinare la legge di flusso dei materiali lavorati. La ricerca futura sarà focalizzata sulla simulazione FE dell'usura dell'utensile e dell'integrità della superficie del pezzo.This thesis is focused on Micro-Machining (MM) processes applied on Additively Manufactured parts. MM processes are a class of manufacturing technology designed to produce small size components. In general, cutting processes are characterized by a mechanical interaction between a workpiece and a tool. The contact determines a material breakage along a defined path, obtaining different workpiece shapes. More specifically, the micro-machining designation indicates only the cutting processes performed by using a tool with a diameter lower than 1 mm. The reduction of the process scale introduces some critical issues, such as size effect, burr formation, rapid tool wear, higher than expected cutting forces and tool run-out. In the last decades, several researchers have tackled micro-machining related issues, but few of them focused on workability of Additive Manufactured materials. Additive Manufacturing (AM) is a collection of layer-by-layer building processes which can be successfully employed using polymers, ceramics and metals. AM of metals is rapidly spreading throughout the industrial manufacturing finding applications in several branches, such as aerospace and biomedical industries. Moreover, the final product quality is not comparable with the standards achievable through the conventional subtractive material removal methods. The main drawback of additively manufactured components in metals is the low quality of the surface finish and the high surface roughness, therefore further post-process surface treatments are usually required to finish and to refine the surfaces of the build product. The embedding between the two technologies offers relevant opportunities, but the necessity of further studies and investigation is highlighted by the lack of publication about this topic. This research aimed to explore several micro-machining issues with regards to Additive Manufactured metals. Experimental tests were performed by using the ultraprecision 5-axes machining center “KERN Pyramid Nano”, while the AM samples were provided by companies and research groups. The experimental equipment was set-up to perform micro-milling and to monitor the process online by measuring the cutting force. The material removal behavior was investigated and described by means of analytical models and FEM simulations. FE methods were employed also to perform a comparison between the predicted cutting forces and the experimental loads, with the final purpose of refining the flow stress law of the machined materials. The future research will be focused on the FE simulation of the tool wear and the workpiece surface integrity by means of specific subroutines

An Analytical Solution for Probabilistic Guarantees of Reservation Based Soft Real-Time Systems

We show a methodology for the computation of the probability of deadline miss for a periodic real-time task scheduled by a resource reservation algorithm. We propose a modelling technique for the system that reduces the computation of such a probability to that of the steady state probability of an infinite state Discrete Time Markov Chain with a periodic structure. This structure is exploited to develop an efficient numeric solution where different accuracy/computation time trade-offs can be obtained by operating on the granularity of the model. More importantly we offer a closed form conservative bound for the probability of a deadline miss. Our experiments reveal that the bound remains reasonably close to the experimental probability in one real-time application of practical interest. When this bound is used for the optimisation of the overall Quality of Service for a set of tasks sharing the CPU, it produces a good sub-optimal solution in a small amount of time.Comment: IEEE Transactions on Parallel and Distributed Systems, Volume:27, Issue: 3, March 201

The Benefits and Impact of COVID Lockdown on the Environment

Evidence-based research indicates that river basins are cleaner due to fewer people driving due to community lockdowns. Further, air quality has improved due to lessened home-to-work/school transportation and more Work-From-Home (WFH) remote options. Moreover, governments are experiencing challenges providing food to the most vulnerable communities from a food security standpoint. For example, those in global slums are particularly challenged during this time. Air, water, soil, and noise pollution have diminished since the pandemic as manufacturing production has been severely reduced in some industries. Food quality has been diminished because manufacturers are focused more on the quality of products rather than on perceived consumer quality. Solid and waste challenges abound as the use of hand sanitizers and chemicals to reduce the spread of the COVID-19 virus have created elevated levels of chemicals in waste programs threatening to refuse environmental factors and soil quality via toxic substances. The impacts of growth on the ecosystem are global because some species are in an overabundance within the food cycle, threatening the delicate balance of nature. On the other hand, algae overgrowth has lessened because of less carbon and nitrogen emissions. Also, human traffic and visitations to international parks have decreased. For instance, in Canada and other nature parks, animals on the plains now run free because of social distancing measures and park closures. From an economic perspective, as some industries have grown (masks/sanitation chemical/respirator production), others have declined (transportation/aviation). As a result, the pandemic has reduced air quality impacts of commercial aviation travel and lessened global cargo, which has reduced air and sound emissions worldwid

Preface: Implementing Diversity, Equity, Inclusion, and Belonging Management in Organizational Change Initiatives

Implementing Diversity, Equity, Inclusion, and Belonging Management in Organizational Change Initiatives is an indispensable reference source that provides an interdisciplinary perspective of how issues and challenges pertaining to Diversity, Equity, Inclusion, and Belonging Management (DEIB) affect organizational performance. Additionally, there has been a fundamental shift in the importance of DEIB initiatives in organizations. Further, as leaders navigate change management, they must ask themselves critical questions: what went right, wrong, and what can be improved? Leaders must encourage stakeholders’ to openly share their experiences when DEIB issues arise. Leaders may find challenges engaging stakeholders’ due to a myriad of concerns yet must institutionalize, implement, execute, and review DEIB initiatives to ensure organizations are safe, inclusive, and productive. Likewise, leaders must recognize that stakeholder engagement is valuable, not an obstacle when trying to alleviate challenges in change management initiatives. Through well-organized change management development, DEIB issues are dismantled. The ability of leaders to provide DEIB solutions is critical for creating an organizational culture of equity, equality, belonging, inclusion, and shared responsibility. This text highlights research on topics such as diversity, equity, inclusion, and belonging (DEIB), change management, collaborative leadership, DEIB leadership, organizational development, organizational leadership, strategic management, shared leadership, and stakeholder development

Chapter 1: The Merits of a Chief Diversity Officer (CDO): Enterprise Training Program Strategy

Developing an enterprise training program requires a commitment to cultivating diversity, equity, inclusion, and belonging (DEIB) organizational initiatives while providing alignment to the organizational mission, vision, and ethos. With this knowledge, enterprise training programs benefit organizations by fostering authentic cultures to resolve persistent issues of bias, implicit bias, and offenses of corporate policies. As a value, organizational leadership must lead and champion diversity initiatives to ensure stakeholders understand the importance of complying with organizational policies. The problem is that effective DEIB initiatives need implementation or an overhaul. Institutional DEIB initiatives fail because they have yet to identify the rationale for program development, provide financial investment, indicate specific and measurable program improvements, identify appropriate stakeholders to achieve institutional goals, and ensure implementation of streamlined program processes so that facilitators have needed administrative, instructional, and professional support

Chapter 1: Organizational Climate Change: Diversity, Equity, Inclusion, and Belonging

Increasing knowledge and understanding of diversity and inclusion is a continuous process. Appropriately, the organizational chief diversity officer (CDO) provides leadership by implementing strategic business and planning process solutions. The CDO’s role presents a unique opportunity for organizations to support the CDO with an onboarding and mentoring framework. Additionally, the role of the chief diversity officer is to mitigate workplace stress. Further, the impact of industrial and organizational psychology on cultural assimilation practices in the workforce improves the understanding of behavioral factors of group dynamics. As a result, group dynamics impact diversity and inclusion initiatives. Provided are recommendations to support CDOs in their execution of diversity, equity, inclusion, and belonging initiatives

Chapter 7: The Business Case for Implementing a Diversity and Inclusion Quality-Based Strategy

Diversity, equity, inclusion, and belonging (DEIB) strategy consists of theories, concepts, and methods that managers can use to ensure organizations achieve profitability and long-term growth. A DEIB strategy utilizing quality management principles helps leaders make better decisions to improve competitive position and create value for its key stakeholders. This chapter provides managers and leaders a perspective on organizational development. Further, DEIB strategic thinking applies to organizations regardless of their activities. This chapter introduces DEIB leaders to the main theories, concepts, and models of strategic analysis from a quality perspective and emphasizes their role in diversity management practices