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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Replikation kann helfen, in einem verteilten System die Fehlertoleranz und Datensicherheit zu verbessern. In Systemen, die über Weitverkehrsnetze kommunizieren oder mobile Endgeräte einschließen, muß das Replikationssystem mit großen Kommunikationslatenzen umgehen können. Deshalb werden in solchen Systemen in der Regel nur asynchrone Replikationsalgorithmen mit schwach-konsistenter Änderungssemantik eingesetzt, da diese die lokale Annahme von Änderungen der Daten und deren Koordinierung mit anderen Replikaten entkoppeln und somit ein schnelles Antwortverhalten bieten können. Diese Dissertation stellt einen Ansatz für die Entwicklung schwach-konsistenter Replikationssysteme mit erweiterten kausalen Konsistenzgarantien vor und weist nach, daß auf seiner Grundlage effiziente Replikationssysteme konstruiert werden können. Dazu werden Mechanismen, Algorithmen und Protokolle vorgestellt, die Änderungen an replizierten Daten aufzeichnen und verteilen und dabei Kausalitätsbeziehungen erhalten. Kern ist ein Änderungsprotokoll, das sowohl als grundlegende Datenstruktur der verteilten Algorithmen agiert, als auch für die Konsistenz der lokalen Daten nach Systemabstürzen sorgt. Die kausalen Garantien werden mit Hilfe von zwei Algorithmen erweitet, die gleichzeitige Änderungen konsistent handhaben. Beide Algorithmen basieren auf der Beobachtung, daß die Divergenz der Replikate durch unkoordinierte, gleichzeitige Änderungen nicht unbedingt als Inkonsistenz gesehen werden muß, sondern auch als das Erzeugen verschiedener Versionen der Daten modelliert werden kann. Distributed Consistent Branching (DCB) erzeugt diese alternativen Versionen der Daten konsistent auf allen Replikaten; Distributed Consistent Cutting (DCC) wählt eine der Versionen konsistent aus. Die vorgestellten Algorithmen und Protokolle wurden in einer Datenbankimplementierung validiert. Mehrere Experimente zeigen ihre Einsetzbarkeit und helfen, ihr Verhalten unter verschiedenen Bedingungen einzuschätzen. / Data replication techniques introduce redundancy into a distributed system architecture that can help solve several of its persistent problems. In wide area or mobile systems, a replication system must be able to deal with the presence of unreliable, high-latency links. Only asynchronous replication algorithms with weak-consistency guarantees can be deployed in these environments, as these algorithms decouple the local acceptance of changes to the replicated data from coordination with remote replicas. This dissertation proposes a framework for building weak-consistency replication systems that provides the application developer with causal consistency guarantees and mechanisms for handling concurrency. By presenting an integrated set of mechanisms, algorithms and protocols for capturing and disseminating changes to the replicated data, we show that causal consistency and concurrency handling can be implemented in an efficient and versatile manner. The framework is founded on log of changes, which both acts the core data structure for its distributed algorithms and protocols and serves as the database log that ensures the consistency of the local data replica. The causal consistency guarantees are complemented with two distributed algorithms that handle concurrent operations. Both algorithms are based on the observation that uncoordinated concurrent operations introduce a divergence of state in a replication system that can be modeled as the creation of version branches. Distributed Consistent Branching (DCB) recreates these branches on all participating processes in a consistent manner. Distributed Consistent Cutting (DCC) selects one of the possible branches in a consistent and application-controllable manner and enforces a total causal order for all its operations. The contributed algorithms and protocols were validated in an database system implementation, and several experiments assess the behavior of these algorithms and protocols under varying conditions.