| 1. |
- Trinh, Cong Quy, 1983-
(author)
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Automated Verification of Data Properties and Linearizability for Heap-Manipulating Programs
- 2024
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Doctoral thesis (other academic/artistic)abstract
- Software verification is the process of verifying a software application by checking whether it satisfies requirements. Tha automated verification of programs is one of the most challenging problems in software verification. The problem becomes even more challenging when dealing with concurrent programs that dynamically allocate memory on the heap. In this thesis we propose methods for verifying both safety, shape, and linearizability properties of both sequential and concurrent heap-manipulating programs. In short, linearizability means that concurrent operations appear to be executed atomically on a single machine. Such programs induce an infinite-state space in several dimensions: they consist of an unbounded number of concurrent threads, an unbounded number of pointers, they use unbounded dynamically allocated memory, and the domain of data values is unbounded. In addition, we verify linearizability properties of concurrent programs whose linearization points are either fixed or depend on the future execution of the program. In this thesis, we describe three approaches for verifying safety, shape, and linearizability properties.In the first approach, we present a framework for verifying programs that manipulate dynamic linked data structures, whose correctness depends on ordering relations between data values. Our framework extends that of forest automata, in which the heap is described by a set of tree automata, by adding data constraints that express relationships between data elements associated with cells of the heap. This approach works for verifying safety property of sequential programs.In the second approach, we present a framework for automatically verifying linearizability of concurrent data structures with an unbounded number of threads. In this framework, non-fixed linearization points (LPs) are handled by asking the user to specify so-called linearization policies, which are mechanisms for assigning LPs to executions. To handle an unbounded number of threads, we use the thread-modular approach which allows to bound the number of considered threads. To handle an unbounded heap, we define an abstraction, which precisely describes the parts of the heap that are visible (reachable) from global variables, and makes a succinct representation of the parts that are local to threads. We have applied the framework to prove linearizability for a wide range of concurrent data structures based on singly-linked lists.In the third approach, we present a novel shape analysis that can handle heap structures which are more complex than just singly-linked lists, in particular we handle skip lists and arrays of singly linked lists, while at the same time handling an unbounded number of concurrent threads, an unbounded domain of data values (including timestamps), and an unbounded shared heap. Our approach represents a set of heaps by a set of so-called fragments. A fragment is an abstraction of a pair of heap cells that are connected by a pointer field. To the best of our knowledge, our framework is the first that can automatically verify concurrent data structure implementations that employ singly linked lists, skiplists as well as arrays of singly linked lists, at the same time as handling an unbounded number of concurrent threads, an unbounded domain of data values (including timestamps), and an unbounded shared heap.
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| 2. |
- Ahlgren, Kerstin M.
(author)
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Immunological Studies using Human and Canine Model Disorders
- 2011
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Doctoral thesis (other academic/artistic)abstract
- The studies presented in this thesis focus on human and canine models for autoimmune disease, with the main aim to gain new knowledge about disease mechanisms and to further evaluate the dog as a model for autoimmune disease. Autoimmune Polyendocrine Syndrome type 1 (APS-1) is a hereditary human multiorgan disease caused by mutations in the autoimmune regulator (AIRE) gene. Hallmarks of APS-1 are chronic mucocutaneous candidiasis caused by Candida albicans, together with the autoimmune endocrine disorders hypoparathyroidism and adrenocortical failure. Many human diseases have an equivalent disease in dogs. Because humans share environment, and in part life style with the dogs they provide an interesting model for further genetic studies. Immune responses to Candida albicans in APS-1 patients displayed an increased secretion of the proinflammatory cytokine IL-17A and similar results were also found in AIRE deficient mice. Anticytokine autoantibodies to IL-17A, IL-17F and IL-22 were detected in APS-1 patients, and a radioligand binding assay for measuring these autoantibodies was developed and evaluated. In the canine studies we investigated whether canine diabetes mellitus could serve as a model for human autoimmune diabetes mellitus. Furthermore, we investigated type I IFN responses in Nova Scotia duck tolling retriever dogs with a systemic autoimmune disease resembling human SLE. Four assays were used in search for signs of humoral autoimmunity in diabetic dogs. However, no evidence for a type 1 diabetes-like phenotype in dogs was found. Sera from Nova Scotia duck tolling retrievers suffering from steroid-responsive meningitis arteritis elicited an increased expression of IFN-inducible genes in the canine MDCK cell line. This suggests that these dogs have an IFN signature, as seen in human SLE.
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| 3. |
- Almqvist, Roland M, 1964-
(author)
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Icons of New Public Management : four studies on competition, contracts and control
- 2004
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Doctoral thesis (other academic/artistic)abstract
- Public organizations have undergone major changes over the past few decades. The umbrella term used to characterize these changes in the style of public administration is ‘New Public Management’ (NPM). NPM is a cluster of ideas borrowed from the conceptual framework of private-sector administrative practice –– a multifarious concept, covering diverse ideas and theories about what the nature of public management and administration should be. Arguably, then, NPM is primarily not a practitioners’ product but, rather, a construct of the research community, which assembled the programmatic aspects of NPM. The impact of these programmatic aspects on public administrative routines, operations and everyday work is a matter of analysis at the technological level.This thesis studies both the programmatic and the technological aspects of NPM. It focuses on how the programmatic aspects of NPM transform into technological aspects and how we can understand the outcome of these transformations, i.e. NPM’s impact on public administrative practice. The four discrete papers of the thesis cover three aspects (‘Icons’) of NPM – ‘Competition’, ‘Contracts’ and ‘Control’ – in depth:1. Paper I presents a method for isolating effects of the competition threat, with three possible approaches. All three include cost-cutting with respect to full-time annual staff appointments, but combine it with a number of changing variables. The results indicate one plausible conclusion: that one effect of the threat of competition has been to boost savings. In the units concerned, this effect – in terms of a mean cost reduction – may be estimated between 4 and 6 per cent.2. Paper II seeks to study how quality issues have been managed by contract. First, it presents some of the conceptual (programmatic) arguments of ‘Management by Contract’, discussing the structural arguments generally used (the purchaser/ provider split) and a common method (competitive tendering). Second, it presents some technological effects based on empirical findings. The paper’s concluding statement is that there is a gap between the programmatic and technological dimensions. Five interpretations intended to explain this gap are put forward.3. Paper III investigates the existence and function of various mechanisms of internal change in relation to broader aspects of change and characteristics of management control systems. The findings indicate that organizations can continuously transform their management control systems by creating, and promoting the use of, specific transformation mechanisms. In the two organizations studied, these mechanisms include internal benchmarking and internal contracting.4. Paper IV evaluates the City of Stockholm’s decentralization reform, which resulted in 24 local suborganizations (district councils). The empirical findings do not appear to fit into a single, allembracing theory, and the kaleidoscopic nature of the reform demands a broad, multidisciplinary approach. This paper therefore contributes to knowledge of the organizational changes that took place by addressing them both in rational terms and as symbolic acts. Although reforms tend to be perceived as ways of shaking up an organization, it is suggested here that they may in fact have a cohesive function – serving to hold the organization together.One general conclusion of this thesis is that NPM cannot readily be described in terms of success or failure. Instead, the four papers provide widely varying perspectives on, and interpretations of, NPM’s practical impact and the technologies that are taking shape in the field. Based on the notion of NPM as a management doctrine, seven contradictory general observations are presented. Sometimes all goes according to plan. Alternatively, the outcome may deviate from the plan; the result may be ‘business as usual’, i.e. little may change; things may only get worse; programmes may have contradictory effects; change may be excessive; and, finally, there may be unexpected but positive effects. Here, the conclusion is that in some cases the solution is to develop the theories and concepts, i.e. the programmatic level, while in others the solution may, instead, involve developing the application and implementation of existing theories and concepts – i.e. the technological level.
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| 4. |
- Andrén, Maria, 1976-
(author)
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The Role of Fc Gamma Receptors in Experimental Arthritis
- 2004
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Doctoral thesis (other academic/artistic)abstract
- Induction of collagen-induced arthritis (CIA), an animal model for human rheumatoid arthritis, is dependent on anti-collagen type II (CII) antibodies. The effector mechanism by which autoantibodies contribute to inflammatory reactions in autoimmune diseases is not well understood. In this thesis I have studied the effector pathways used by IgG anti-CII antibodies to initiate arthritis, namely the IgG Fc receptors (FcγRs) and the complement system. We have found that FcγRIII is crucial for development of CIA, as CII-immunized mice lacking this receptor do not develop arthritis and IgG1 and IgG2b anti-CII antibodies require FcγRIII to trigger arthritis when transferred to naïve mice. The antibody-mediated arthritis was further enhanced in mice deficient in the inhibitory FcγRIIB, indicating that FcγRIIB regulates the activation of FcγRIII. Furthermore, we demonstrate that FcγRIII exist as three distinct haplotypes in mice, FcγRIII:H, FcγRIII:V and FcγRIII:T. Mice expressing the FcγRIII:H haplotype are more susceptible to CIA than mice expressing the FcγRIII:V haplotype, indicating that certain FcγRIII haplotype predisposes for CIA. We also show that the most likely FcγRIII-expressing effector cell in CIA is the macrophage, since FcγRIII-expressing macrophages exclusively can induce arthritis in FcγRIII-deficient mice challenged for CIA.The complement system was also investigated in development of CIA. We found that this effector pathway is also necessary for onset of arthritis, as CIA was inhibited by treatment with anti-complement factor 5 (C5) antibodies. C5-deficient mice could neither develop CIA unless provided with C5-containing sera. Taken together, the work presented in this thesis indicates that FcγRs and the complement system are crucial for the induction of experimental arthritis. These findings are important for understanding the mechanisms behind rheumatoid arthritis and blocking of these effector pathways may in the future be used as treatment of rheumatoid arthritis.
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| 5. |
- Krämer, Roland H.
(author)
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Combustion dynamics and melt dripping of ethylene-acrylate copolyer composites
- 2007
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Licentiate thesis (other academic/artistic)abstract
- The degradation and combustion of blends of ethylene-acryalte copolymer with calcium carbonate and silicone were studied by a combination of flammability tests, in-situ measurements and analytical experiments. Compounds of poly(ethylene-co-methacrylic acid) blended with precipitated calcium carbonate nanoparticles were prepared. The thermo-oxidative stability of these composites was significantly enhanced and thermal degradation led to the formation of calcium salts that stabilize the acrylic acid side group. Improved mechanical properties over micron-sized composites were obtained. The temperature dependence of the salt formation was analyzed in order to judge its relevance to combustion. The combustion of poly(ethylene-co-methacrylic acid), poly(ethylene-co-butylacrylate) and poly(ethylene-co-butylacrylate) with polypropylene, each blended with silicone and micron-sized chalk, was studied in the cone calorimeter. A combination of in-situ temperature measurements and analysis of degraded specimens quenched from the combustion process led to a detailed understanding of the dynamics of the materials’ intumescence. Differences in heat release for the different types of polymers can be explained and requirements for improved formulations were found. The char stability and melt viscosity of the materials were tested in a series of vertical flame and vertical cone calorimeter experiments. The scope of such measurements is discussed. The experiments were complemented with rheological and analytical measurements to explore the role of the physico-chemical degradation processes in the melt dripping.
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| 6. |
- Kuzmin, Leonid
(author)
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Interfacial kinetic ski friction
- 2010
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Doctoral thesis (other academic/artistic)abstract
- It is no doubt, that the ski glide over the snow is a very complicated object of research. However, ski glide is just a one area of many other areas of human knowledge. As a rule, the scientists and practitioners, who work in these areas, operate with some publicly expressed more or less solid hypotheses. These researchers work with one hypothesis until another and a better one comes up. Our literature studies and our own observations regarding modern skis preparations, did not give us any solid hypotheses, which are able to explain the actual form and content of this procedure. The present work is an attempt to reveal such hypotheses. Conclusion: To achieve an optimal glide on skis with the base (the ski sole) made of some high hydrophobic durable polymer, e.g. UHMWPE, PTFE; we only have to create an adequate topography (texture) on the ski running surface, adequate to the actual snow conditions.
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