Covid-19 pandemin har orsakat ett stort antal sjukdom- och dödsfall i Sverige. Människors beteende är avgörande för smittspridningens utveckling och blir därför värdefullt att undersöka. Aktuell studie testade huruvida Femfaktormodellens personlighetsdimensioner respektive självbetjänande attributionsfelen, bättre-än-medel-effekten och orealistisk optimism, samvarierar med och predicerar smittförebyggande beteenden vid covid-19 pandemin. En enkät besvarades av 126 högskolestudenter från Mellansverige. Resultatet visade inget signifikant samband mellan någon personlighetsdimension och smittförebyggande beteenden. Personlighet kan inte predicera risk- respektive smittförebyggande beteenden. Samtliga mätningar av bättre-än-medel-effekter och orealistisk optimism visade positiva samband med smittförebyggande beteenden varav enbart bättre-än-medel-effekten vad gäller den egna förmågan att skydda sig mot smitta kunde förklara variation i smittförebyggande beteenden. Intressant för framtida studier är att undersöka vad som ligger till grund för dessa resultat samt vidare undersöka vad annat som kan förklara människors beteenden vid pandemiska kriser.

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The goal of this thesis is to create a financial project of Take-over Company and specify the steps that lead to its profitability. The thesis is divided into two parts. The first, theoretical section describes the calculations used, marketing plan and market analysis. The second part is practical and there is specifically described a plan how to deal with building a restaurant with bowling and beach sports pitch in the town Rakovník and what is the expected development during the first five years. Key to the success of company is the marketing plan and the use of employee benefits in the cooperating companies. The thesis should provide the appropriate basis for investor and subsequent realization of the project.

Suicidal behavior, including suicide attempt, may result from maladaptive explanatory patterns for past negative life events, in which a person attributes the causes of stressors to internal, stable and global factors. Conversely, an optimistic explanatory style involves perceiving negative life events as external, transient and specific, and may be related to reduced suicide risk. We examined the association between attributional style and lifetime suicide attempts in 135 college students, covarying age, race and ethnicity. Participants provided informed consent and completed an online survey. An optimistic explanatory style was associated with reduced risk of suicide attempt; this effect persisted in a model controlling for hopelessness and depressive symptoms. The manner in which an individual interprets negative life events may buffer against suicidal behavior. Therapeutic strategies to promote an optimistic explanatory style may be successful in the prevention of suicide.

Cellular space modeling is becoming an increasingly important modeling paradigm for modeling complex systems with spatial-temporal behaviors. The growing demand for cellular space models has directed researchers to use different modeling formalisms, among which Discrete Event System Specification (DEVS) is widely used due to its formal modeling and simulation framework. The increasing complexity of systems to be modeled asks for cellular space models with large number of cells for modeling the systems¡¯ spatial-temporal behavior. Improving simulation performance becomes crucial for simulating large scale cellular space models. In this dissertation, we proposed a framework for improving simulation performance for large scale DEVS-based cellular space models. The framework has a layered structure, which includes modeling, simulation, and network layers corresponding to the DEVS-based modeling and simulation architecture. Based on this framework, we developed methods at each layer to overcome performance issues for simulating large scale cellular space models. Specifically, to increase the runtime and memory efficiency for simulating large number of cells, we applied Dynamic Structure DEVS (DSDEVS) to cellular space modeling and carried out comprehensive performance measurement. DSDEVS improves simulation performance by making the simulation focus only on those active models, and thus be more efficient than when the entire cellular space is loaded. To reduce the number of simulation cycles caused by extensive message passing among cells, we developed a pre-schedule modeling approach that exploits the model behavior for improving simulation performance. At the network layer, we developed a modified time-warp algorithm that supports parallel simulation of DEVS-based cellular space models. The developed methods have been applied to large scale wildfire spread simulations based on the DEVS-FIRE simulation environment and have achieved significant performance results.

In this thesis, we propose a family of concurrency control protocols for high data contention database environments. The first one is called the Prudent-Precedence Concurrency Control (PPCC) protocol. It is prudently more aggressive in permitting more serializable schedules than two-phase locking and maintains a restricted precedence among conflicting transactions and commits the transactions according to the serialization order established in the executions. The second one is a family of hierarchical concurrency control protocols called the Hierarchical Precedence Concurrency Control (HPCC) protocols. It maintains cycle-free precedence hierarchies for conflicting transactions. Conflicting operations are allowed to proceed only if the hierarchical orderings of precedence is not violated. Transactions also commit based on the serialization order established during the executions. Detailed simulation models have been implemented for all these protocols and extensive experiments have been conducted to evaluate the performance of the proposed approaches. The results demonstrate that the proposed algorithms outperform the two-phase locking and optimistic concurrency control over a wide range of system workloads.

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My sculptural installations aim to elicit a sense of optimism and possibility through form, color, and mode of display. The work subverts the symbolic order by repurposing everyday forms and objects, allowing us to see the familiar as new, and thereby awakening us to what may be possible to formulate a better, more beautiful, more universally connected order.

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Pour fournir une disponibilité permanente des données et réduire la latence réseau, les systèmes de partage de données se basent sur la réplication optimiste. Dans ce paradigme, il existe plusieurs copies de l'objet partagé dite répliques stockées sur des sites. Ces répliques peuvent être modifiées librement et à tout moment. Les modifications sont exécutées en local puis propagées aux autres sites pour y être appliquées. Les algorithmes de réplication optimiste sont chargés de gérer les modifications parallèles. L'objectif de cette thèse est de proposer une méthodologie d'évaluation pour les algorithmes de réplication optimiste. Le contexte de notre étude est l'édition collaborative. Nous allons concevoir pour cela un outil d'évaluation qui intègre un mécanisme de génération de corpus et un simulateur d'édition collaborative. À travers cet outil, nous allons dérouler plusieurs expériences sur deux types de corpus: synchrone et asynchrone. Dans le cas d'une édition collaborative synchrone, nous évaluerons les performances des différents algorithmes de réplication sur différents critères tels que le temps d'exécution, l'occupation mémoire, la taille des messages, etc. Nous proposerons ensuite quelques améliorations. En plus, dans le cas d'une édition collaborative asynchrone, lorsque deux répliques se synchronisent, les conflits sont plus nombreux à apparaître. Le système peut bloquer la fusion des modifications jusqu'à ce que l'utilisateur résolut les conflits. Pour réduire le nombre de ces conflits et l'effort des utilisateurs, nous proposerons une métrique d'évaluation et nous évaluerons les différents algorithmes sur cette métrique. Nous analyserons le résultat pour comprendre le comportement des utilisateurs et nous proposerons ensuite des algorithmes pour résoudre les conflits les plus important et réduire ainsi l'effort des développeurs. Enfin, nous proposerons une nouvelle architecture hybride basée sur deux types d'algorithmes de réplication. Contrairement aux architectures actuelles, l'architecture proposéeest simple, limite les ressources sur les dispositifs clients et ne nécessite pas de consensus entre les centres de données / To provide a high availability from any where, at any time, with low latency, data is optimistically replicated. This model allows any replica to apply updates locally, while the operations are later sent to all the others. In this way, all replicas eventually apply all updates, possibly even in different order. Optimistic replication algorithms are responsible for managing the concurrent modifications and ensure the consistency of the shared object. In this thesis, we present an evaluation methodology for optimistic replication algorithms. The context of our study is collaborative editing. We designed a tool that implements our methodology. This tool integrates a mechanism to generate a corpus and a simulator to simulate sessions of collaborative editing. Through this tool, we made several experiments on two different corpus: synchronous and asynchronous. In synchronous collaboration, we evaluate the performance of optimistic replication algorithms following several criteria such as execution time, memory occupation, message's size, etc. After analysis, some improvements were proposed. In addition, in asynchronous collaboration, when replicas synchronize their modifications, more conflicts can appear in the document. In this case, the system cannot merge the modifications until a user resolves them. In order to reduce the conflicts and the user's effort, we propose an evaluation metric and we evaluate the different algorithms on this metric. Afterward, we analyze the quality of the merge to understand the behavior of the users and the collaboration cases that create conflicts. Then, we propose algorithms for resolving the most important conflicts, therefore reducing the user's effort. Finally, we propose a new architecture for supporting cloud-based collaborative editing system. This architecture is based on two optimistic replication algorithms. Unlike current architectures, the proposed one removes the problems of the centralization and consensus between data centers, is simple and accessible for any developers