No description available.

The behaviour of distributed applications can be modeled as the occurrence of events and how these events relate to each other. Event data collected according to this event model can be visualized using process-time diagrams that are constructed from a collection of traces and events. One of the main characteristics of a distributed system is the large number of events that are involved, especially in practical situations. This large number of events, and hence large process-time diagrams, make distributed-system observation difficult for the user. However, event-predicate detection, a search mechanism able to detect and locate arbitrary predicates within a process-time diagram or event collection, can help the user to make sense of this large amount of data. Ping Xie used the convex-abstract event concept, developed by Thomas Kunz, to search for hierarchical event predicates. However, his algorithm for computing convex closure to construct compound events, and especially hierarchical compound events (i. e. , compound events that contain other compound events), is inefficient. In one case it took, on average, close to four hours to search the collection of event data for a specific hierarchical event predicate. In another case, it took nearly one hour. This dissertation discusses an efficient algorithm, an extension of Ping Xie?s algorithm, that employs a caching scheme to build compound and hierarchical compound events based on matched sub-patterns. In both cases cited above, the new execution times were reduced by over 94%. They now take, on average, less than four minutes.

New event detection, also known as first story detection (FSD), has become very popular in recent years. The task consists of finding previously unseen events from a stream of documents. Despite the apparent simplicity, FSD is very challenging and has applications anywhere where timely access to fresh information is crucial: from journalism to stock market trading, homeland security, or emergency response. With the rise of user generated content and citizen journalism we have entered an era of big and noisy data, yet traditional approaches for solving FSD are not designed to deal with this new type of data. The amount of information that is being generated today exceeds by many orders of magnitude previously available datasets, making traditional approaches obsolete for modern event detection. In this thesis, we propose a modern approach to event detection that scales to unbounded streams of text, without sacrificing accuracy. This is a crucial property that enables us to detect events from large streams like Twitter, which none of the previous approaches were able to do. One of the major problems in detecting new events is vocabulary mismatch, also known as lexical variation. This problem is characterized by different authors using different words to describe the same event, and it is inherent to human language. We show how to mitigate this problem in FSD by using paraphrases. Our approach that uses paraphrases achieves state-of-the-art results on the FSD task, while still maintaining efficiency and being able to process unbounded streams. Another important property of user generated content is the high level of noise, and Twitter is no exception. This is another problem that traditional approaches were not designed to deal with, and here we investigate different methods of reducing the amount of noise. We show that by using information from Wikipedia, it is possible to significantly reduce the amount of spurious events detected in Twitter, while maintaining a very small latency in detection. A question is often raised as to whether Twitter is at all useful, especially if one has access to a high-quality stream such as the newswire, or if it should be considered as sort of a poor man’s newswire. In our comparison of these two streams we find that Twitter contains events not present in the newswire, and that it also breaks some events sooner, showing that it is useful for event detection, even in the presence of newswire.

This work is the result of the definition, design and evaluation of a novel method to interconnect the computational elements - commonly known as Configurable Analogue Blocks (CABs) - of a programmable analogue array. This method is proposed for total or partial replacement of the conventional methods due to serious limitations of the latter in terms of scalability. With this method, named Asynchronous Spike Event Coding (ASEC) scheme, analogue signals from CABs outputs are encoded as time instants (spike events) dependent upon those signals activity and are transmitted asynchronously by employing the Address Event Representation (AER) protocol. Power dissipation is dependent upon input signal activity and no spike events are generated when the input signal is constant. On-line, programmable computation is intrinsic to ASEC scheme and is performed without additional hardware. The ability of the communication scheme to perform computation enhances the computation power of the programmable analogue array. The design methodology and a CMOS implementation of the scheme are presented together with test results from prototype integrated circuits (ICs).

The topic of this thesis is cognitive control: how the brain organises itself to perform the many tasks it is capable of and how it switches flexibly among them. Task-switching experiments reveal a substantial cost in reaction time and accuracy after a switch in tasks. This "switch cost" is reduced by preparation (suggesting anticipatory task-set reconfiguration), but not eliminated. The thesis focuses on the sources of the "residual" cost. Most accounts attribute it to response selection being prolonged on a task-switch trial by task conflict, e.g. by 'task-set inertia' — persisting activation/inhibition of the previous task's S-R rules — or their associative reactivation by the stimulus. Four experiments used event-related potentials (ERPs) to determine which stages of task processing are influenced by a change in tasks, looking for delays in process-specific markers in the ERP. Experiments 1 and 2 showed that a prepared switch to a reading task from a perceptual judgement delayed early ERP markers of lexical access by a large fraction of the RT switch cost, suggesting that a substantial part of the residual cost arises in processes earlier than response selection, possibly due to task-related attentional inertia. Markers of lexical access observed in the non-lexical task were larger on switch than repeat trials, providing the first electrophysiological evidence of task-set inertia. Experiment 3 examined the effects of an unprepared switch in the same way. ERP waveforms were modulated by a switch before markers of lexical access were evident, suggesting additional processing demands compete for resources with lexical access. A simple delay, however, was not found; post-stimulus task-set reconfiguration does not just insert an extra processing stage. Experiment 4 looked for a delay in the onset of an early ERP marker of emotional processing when the task switched between categorising facial expression and classifying a superimposed letter. No such delay was found in this case, and ERP markers of emotion processing were present to the same extent in the letter task. This suggests that, given appropriate spatial attention, processing facial emotion unfolds automatically, independent of attention allocation to the facial features. Experiments 5-7 further explored the link between conflict due to processing the irrelevant stimulus dimension and the ERP post-stimulus negativity that accompanies the residual cost. The negativity could be elicited even on trials of non-switching blocks by prior training on classifying the irrelevant attribute of the stimulus using the same responses. But this effect did not seem to result from the trained class of irrelevant attribute attracting more attention. Finally, Experiment 8 followed up an incidental observation in Experiment 1 to establish the novel observation that a task-switching context abolishes the usual ERP correlate of withholding a response in a go/no-go paradigm, suggesting an interesting interaction between task-set control and response inhibition.

The aim of this research was to discuss about event management theory and how the Liiga (the major ice hockey league in Finland) team organisations could use this theory to improve their home game events. This topic has been divided into two research questions from which the first discusses the current situation and the other gives suggestions for future improvements for the Liiga team organisations. This research is conducted as a master’s theses and it has been conducted in years 2014 to 2016. In order to understand the research topic the general theory of event management has been told from the sporting event point of view. This theory has been divided into two different sections which are the five stages of event management and the operational strategies of event management. Answers for the research questions have been search with a qualitative research and its methods of interview and questionnaire, observation and content analysis. These methods and the way these have been used in this research are introduced after the event management theory. The data collected with the selected qualitative research methods has been introduced as empirical findings. These empirical findings are introduced a research method at a time and in a same order as the data has been collected. After introducing the collected data it has been carefully analysed. The analysis have also been divided into two section from which the first answers to the first research question concerning the current situation and the other the second questions concerning the future improvement that could be done. The first part of analysis has been made in a same chronological order as the event management theory has been written in order it to be easy to compere these two to each other. In the end the conclusions of this research and its research questions are introduced. Also the knowledge which this research is offering for the tourism industry and for its readers have been discussed. This are also a lot of different ways how this research could be continued and made further and these ways have been discussed as well. Last but not least the research has been viewed critically and the quality of it has been questioned.

This study investigates whether different acquisition strategies provide dissimilar abnormal returns forthe bidders’ investors before, during and after the financial crisis. The study focuses on acquisitionsconducted by banks between 2004 and 2012. The data is split in a pre-, mid-, and post-crisis sample.The dataset consists out of 950 completed acquisitions conducted by 378 unique banks. Crosssectionalresults point out that investors are generally indifferent to which acquisition strategy is usedby banks, both at announcement and at completion. Moreover, it seems that investors do not reactfiercer to the announcement compared to the completion of a deal. The results are robust whensplitting the sample in acquirers originating from common- and code law countries. However, the studyfinds that opposed to what is suggested by prior research, shareholders from code law countries earnhigher returns than shareholders from common law countries.

Dans cette thèse, nous nous intéressons à la spécification et à la synthèse de contrôleurs des systèmes temps-réels. Les modèles pour ces systèmes sont des Event-recording Automata. Nous supposons que les contrôleurs observent tous les évènements se produisant dans le système et qu'ils peuvent interdirent uniquement des évènements contrôlables. Tous les évènements ne sont pas nécessairement contrôlables. Une première étude est faite sur la logique Event-recording Logic (ERL). Nous proposons des nouveaux algorithmes pour les problèmes de vérification et de satisfaisabilité. Ces algorithmes présentent les similitudes entre les problèmes de décision cité ci-dessus et les problèmes de décision similaires étudiés dans le cadre du $\mu$-calcul. Nos algorithmes corrigent aussi des algorithmes présents dans la littérature. Les similitudes relevées nous permettent de prouver l'équivalence entre les formules de ERL et les formules de ERL en forme normale disjonctive. La logique ERL n'étant pas suffisamment expressive pour décrire certaines propriétés des systèmes, en particulier des propriétés des contrôleurs, nous introduisons une nouvelle logique WT$_\mu$. La logique WT$_\mu$ est une extension temps-réel faible du $\mu$-calcul. Nous proposons des algorithmes pour la vérification des systèmes lorsque les propriétés sont écrites en WT$_\mu$. Nous identifions deux fragments de WT$_\mu$ appelés WT$_\mu$ bien guardé ($WG$-WT$_\mu$) et WT$_\mu$ pour le contrôle ($C$-WT$_\mu$). La logique $WG$-WT$_\mu$ est plus expressif que $C$-WT$_\mu$. Nous proposons un algorithme qui permet de vérifier si une formule de $WG$-WT$_\mu$ possède un modèle (éventuellement déterministe). Cet algorithme nécessite de connaître les ressources (horloges et constante maximale comparée avec les horloges) des modèles. Dans le cadre de $C$-WT$_\mu$ l'algorithme que nous proposons et qui permet de décider si une formule possède un modèle n'a pas besoin de connaître les ressources des modèles. En utilisant $C$-WT$_\mu$ comme langage de spécification des systèmes, nous proposons des algorithmes de décision pour le contrôle centralisé et le $\Delta$-contrôle centralisé. Ces algorithmes permettent aussi de construire des modèles de contr\^oleurs. Lorsque les objectifs de contrôle sont décrits à l'aide des formules de $WG$-WT$_\mu$, nous montrons également comment synthétiser des contrôleurs décentralisés avec des ressources fixées à l'avance et ceci, lorsqu'au plus un contrôleur est non déterministe. / In this dissertation, we consider the specification and the controller synthesis problem for real-time systems. Our models for systems are kinds of Event-recording automata. We assume that controllers observe all the events occurring in the system and can prevent occurrences of controllable events. We study Event-recording Logic (ERL). We propose new algorithms for the model-checking and the satisfiability problems of that logic. Our algorithms are similar to some algorithms proposed for the same problems in the setting of the standard $\mu$-calculus. They also correct earlier proposed algorithms. We define disjunctive normal form formulas and we show that every formula is equivalent to a formula in disjunctive normal form. Unfortunately, ERL is rather weak and can not describe some interesting real-time properties, in particular some important properties for controllers. We define a new logic that we call WT$_\mu$. The logic WT$_\mu$ is a weak real-time extension of the standard $\mu$-calculus. We present an algorithm for the model-checking problem of WT$_\mu$. We consider two fragments of WT$_\mu$ called well guarded WT$_\mu$ ($WG$-WT$_\mu$) and WT$_\mu$ for control ($C$-WT$_\mu$). We show that the satisfiability of $WG$-WT$_\mu$ is decidable if the maximal constants appearing in models are known a priori. Our algorithm allows to check whether a formula of $WG$-WT$_\mu$ has a deterministic model. The algorithm we propose to decide whether a formula of $C$-WT$_\mu$ has a model does not need to know the maximal constant used in models. All the algorithms for the satisfiability checking construct witness models. Using $C$-WT$_\mu$, we present algorithms for a centralised controller synthesis problem and a centralised $\Delta$-controller synthesis problems. The construction of witness controllers is effective. We also consider the decentralised controller synthesis problem with limited resources (the maximal constants used in controllers is known a priory) when the properties are described with $WG$-WT$_\mu$. We show that this problem is decidable and the computation of witness controllers is effective.

Master of Science / Department of Psychological Sciences / Lester Loschky / Film is a ubiquitous medium. However, the process by which we comprehend film narratives is not well understood. Reading research has shown a strong connection between eye-movements and comprehension. In four experiments we tested whether the eye-movement and comprehension relationship held for films. This was done by manipulating viewer comprehension by starting participants at different points in a film, and then tracking their eyes. Overall, the manipulation created large differences in comprehension, but only found small difference in eye-movements. In a condition of the final experiment, a task manipulation was designed to prioritize different stimulus features. This task manipulation created large differences in eye-movements when compared to participants freely viewing the clip. These results indicate that with the implicit task of narrative comprehension, top-down comprehension processes have little effect on eye-movements. To allow for strong, volitional top-down control of eye-movements in film, task manipulations need to make features that are important to comprehension irrelevant to the task.

Understanding the financial value resulting from IS security investments is critically important to organizations focused on protecting service confidentiality, integrity, and availability in order to preserve firm revenues and reputations. Quantifying the financial effect from IS security investments is difficult to derive. This study investigated the relationship between e-banking investments in IS security and their market value impacts. Using an event study approach, the author captured e-banking firm specific data and isolated the IS security effect through the measured change in market values. The author hypothesized that announcements of IS security investments would result in statistically significant changes in market values. The author also hypothesized two sub-segments of the selected security investment data, technology and people, would support statistically significant changes in the market values of e-banking service providers. The hypotheses were tested by measuring stock market reactions to the IS security announcements selected from an eight-year period (2003-2010). Study findings indicated statistically significant market reactions for e-banking firms making IS security investment announcements and suggested that investors rewarded IS security technology investments more highly than e-banking firms making IS security people-focused investment announcements. The author concluded that because investors understand that mandatory regulatory compliance represents an e-banking firm's commitment to creating a secure computing environment, e-banking information systems are perceived as secure therefore, disclosing IS security investments results in weak changes to market values. Ultimately effective management of IS security requires acceptance of the idea that it is not technically feasible or financially viable to implement protections for all identified IS security risks therefore IS security investments must be effectively measured and risk levels consciously selected in order to implement the right technical and operational protections to support a firm's selected risk posture. The study contributes to the event study literature as well as the literature examining the economic effects of information systems security.