Applying Formal Methods to Networking: Theory, Techniques and Applications

Despite its great importance, modern network infrastructure is remarkable for the lack of rigor in its engineering. The Internet which began as a research experiment was never designed to handle the users and applications it hosts today. The lack of formalization of the Internet architecture meant limited abstractions and modularity, especially for the control and management planes, thus requiring for every new need a new protocol built from scratch. This led to an unwieldy ossified Internet architecture resistant to any attempts at formal verification, and an Internet culture where expediency and pragmatism are favored over formal correctness. Fortunately, recent work in the space of clean slate Internet design---especially, the software defined networking (SDN) paradigm---offers the Internet community another chance to develop the right kind of architecture and abstractions. This has also led to a great resurgence in interest of applying formal methods to specification, verification, and synthesis of networking protocols and applications. In this paper, we present a self-contained tutorial of the formidable amount of work that has been done in formal methods, and present a survey of its applications to networking.Comment: 30 pages, submitted to IEEE Communications Surveys and Tutorial

A Unifying Theory for Graph Transformation

The field of graph transformation studies the rule-based transformation of graphs. An important branch is the algebraic graph transformation tradition, in which approaches are defined and studied using the language of category theory. Most algebraic graph transformation approaches (such as DPO, SPO, SqPO, and AGREE) are opinionated about the local contexts that are allowed around matches for rules, and about how replacement in context should work exactly. The approaches also differ considerably in their underlying formal theories and their general expressiveness (e.g., not all frameworks allow duplication). This dissertation proposes an expressive algebraic graph transformation approach, called PBPO+, which is an adaptation of PBPO by Corradini et al. The central contribution is a proof that PBPO+ subsumes (under mild restrictions) DPO, SqPO, AGREE, and PBPO in the important categorical setting of quasitoposes. This result allows for a more unified study of graph transformation metatheory, methods, and tools. A concrete example of this is found in the second major contribution of this dissertation: a graph transformation termination method for PBPO+, based on decreasing interpretations, and defined for general categories. By applying the proposed encodings into PBPO+, this method can also be applied for DPO, SqPO, AGREE, and PBPO

Generating Extended Resolution Proofs with a BDD-Based SAT Solver

In 2006, Biere, Jussila, and Sinz made the key observation that the underlying logic behind algorithms for constructing Reduced, Ordered Binary Decision Diagrams (BDDs) can be encoded as steps in a proof in the extended resolution logical framework. Through this, a BDD-based Boolean satisfiability (SAT) solver can generate a checkable proof of unsatisfiability for a set of clauses. Such a proof indicates that the formula is truly unsatisfiable without requiring the user to trust the BDD package or the SAT solver built on top of it. We extend their work to enable arbitrary existential quantification of the formula variables, a critical capability for BDD-based SAT solvers. We demonstrate the utility of this approach by applying a prototype solver to several problems that are very challenging for search-based SAT solvers, obtaining polynomially sized proofs on benchmarks for parity formulas, as well as the Urquhart, mutilated chessboard, and pigeonhole problems.Comment: Extended version of paper published at TACAS 202

Automated Deduction – CADE 28

This open access book constitutes the proceeding of the 28th International Conference on Automated Deduction, CADE 28, held virtually in July 2021. The 29 full papers and 7 system descriptions presented together with 2 invited papers were carefully reviewed and selected from 76 submissions. CADE is the major forum for the presentation of research in all aspects of automated deduction, including foundations, applications, implementations, and practical experience. The papers are organized in the following topics: Logical foundations; theory and principles; implementation and application; ATP and AI; and system descriptions

Cognitive Behavioral Therapy

Cognitive behavioral therapy (CBT) is a modern type of short-term psychotherapy that integrates cognitive and behavioral theories. The CBT approach is effective in the treatment of a wide range of mental issues and conditions, such as generalized anxiety disorders, general or post-traumatic stress, panic attacks, depression, eating and sleep dysfunctions, obsessive–compulsive disorders, and substance dependence. CBT is also effective as an intervention for psychotic, personality, and bipolar disorders or to approach fatigue and chronic pain conditions especially if associated with distress. This book explains both theoretical and practical aspects of CBT, along with case examples, and contains useful tools and specific interventions for different psychological situations

Iron-Enhanced Mitigation of Viruses in Drinking Water

Waterborne viruses are ubiquitous in the environment and present a global threat to public health. Previous research has suggested that iron-based water treatment has promise as a low-cost, non-toxic means of virus mitigation. In particular, zero-valent and ferrous iron have shown evidence of inactivating bacteria and viruses. The purpose of this research was to elucidate the relationship between iron oxidation and virus inactivation and determine if iron-based inactivation can enhance two water treatment processes, electrocoagulation and electrooxidation, for virus mitigation. This research first investigated bacteriophage inactivation due to ferrous oxidation in batch tests using ferrous chloride salt. Ferrous iron oxidation correlated to bacteriophage inactivation, indicating that viruses can be inactivated as well as physically removed by ferrous iron coagulation. Greater inactivation was associated with both a higher ferrous iron dose and a slower rate of iron oxidation. Next, the importance of ferrous oxidation was determined for virus mitigation via iron electrocoagulation. Ferrous-based inactivation was an important fate of viruses in iron electrocoagulation. However, some bacteriophages showed far greater inactivation than human viruses. Physical removal was the dominant fate under most conditions for the three mammalian viruses tested, as well as bacteriophage ΦX174. This result casts doubt on the appropriateness of using common bacteriophages for research into iron-based water treatment technologies. However, most viruses did demonstrate some inactivation at low pH (pH 6).Finally, an electrocoagulation-electrooxidation treatment train was investigated to capitalize on the strengths of iron electrocoagulation. At typical coagulation doses (\u3c30 mg/L Fe), ferrous iron did not enhance electrooxidation with boron-doped diamond electrodes. Nevertheless, the electrocoagulation-electrooxidation treatment train was beneficial in model surface waters, though electrocoagulation alone achieved equal or better mitigation in model groundwaters. The electrocoagulation-electrooxidation system also outperformed conventional treatment (ferric salt coagulant and free chlorine disinfection) in model groundwaters

Identity – A critical but neglected construct in cognitive-behaviour therapy

In cognitive-behaviour therapy attention paid to the self and identity has primarily involved self-representations (the Me-Self) rather than how the self is experienced (the I-Self). Within the I-Self experiences vary on a continuum from pre-reflective consciousness (raw experienced perceptions and states of being) to self-awareness (permitting reflection on and evaluation of subjective experience). There is considerable evidence that the I-Self is affected in many if not all disorders, and I review illustrative studies of OCD, eating disorders, body dysmorphic disorder, PTSD, and personality disorder. These indicate that patients often experience themselves as being defective in various ways, or as having an unstable or contradictory I-Self. Recognition of this neglected aspect of patients' experience has major implications for assessment and treatment. For example, acknowledgment that their sense of self may fluctuate dramatically from moment to moment, may be fragmented, or may consist of a sense of emptiness, may help to build a more empathic therapeutic relationship. If frightening or distressing pre-reflective experiences are the cause of avoidance or other maladaptive coping strategies, conscious attention paid to them in therapy may help to better integrate the I-Self and Me-Self, restoring a sense of predictability and control

A maturity model for DevOps

Nowadays, businesses aim to respond to customer needs at unprecedented speed. Thus, many companies are rushing to the DevOps movement. DevOps is the combination of Development and Operations and a new way of thinking in the software engineering domain. However, no common understanding of what it means has yet been achieved. Also, no adoption models or fine-grained maturity models to assist DevOps maturation and implementation were identified. Therefore, this research attempt to fill these gaps. A systematic literature review is performed to identify the determining factors contributing to the implementation of DevOps, including the main capabilities and areas with which it evolves. Then, two sets of interviews with DevOps experts were performed and their experience used to build the DevOps Maturity Model. The DevOps maturity model was then developed grounded on scientific and professional viewpoints. Once developed the Maturity Model was demonstrated in a real organisation.info:eu-repo/semantics/acceptedVersio