All Linear-Time Congruences for Familiar Operators

The detailed behaviour of a system is often represented as a labelled transition system (LTS) and the abstract behaviour as a stuttering-insensitive semantic congruence. Numerous congruences have been presented in the literature. On the other hand, there have not been many results proving the absence of more congruences. This publication fully analyses the linear-time (in a well-defined sense) region with respect to action prefix, hiding, relational renaming, and parallel composition. It contains 40 congruences. They are built from the alphabet, two kinds of traces, two kinds of divergence traces, five kinds of failures, and four kinds of infinite traces. In the case of finite LTSs, infinite traces lose their role and the number of congruences drops to 20. The publication concentrates on the hardest and most novel part of the result, that is, proving the absence of more congruences

Hyväksy kaikki evästeet - Käyttöliittymäkomponenttien näkyvyyden vaikutus käyttäjän suorituskykyyn

Tässä pro gradu -työssä tutkitaan miten käyttöliittymäkomponenttien näkyvyys vaikuttaa käyttäjään hänen valitessa kahden vaihtoehdon välillä. Monet palvelut ovat digitalisaatiosta johtuen siirtyneet verkkopalveluiksi ja ne pyytävät aluksi käyttäjiänsä hyväksymään palvelun käytön edellyttämiä tai palvelua parantavia evästeitä. Käyttäjiä ohjataan toimimaan palvelun tarjoajan kannalta edullisesti tarjoamalla huomiota herättävä vaihtoehto hyväksyttäväksi. Työtä varten laadittiin ohjelmisto, jossa käyttäjille esitettiin kolmenlaisia dialogeja, joissa kahdessa käyttöliittymän valittavien vaihtoehtojen välillä oli näkyvyysero. Käyttäjän valittavaksi tarjottiin kahta tavallista painiketta, tai tavallista painiketta taustavärittömän painikkeen tai linkin kanssa. Kokeeseen osallistuneiden 20 käyttäjän toimintaa seurattiin silmänliikekameralasien avulla ja heidän tehtävien suoritusnopeus ja -tarkkuus mitattiin napinpainallusten aikaleimojen avulla. Tehtävät olivat niin helppoja, että melkein kaikki osasivat valita pyydetyn vaihtoehdon, vaikka tehtävä pyydettiin tekemään mahdollisimman nopeasti. Painikkeiden ulkoasulla ei ollut tilastollisesti merkitsevää merkitystä nopeuteen, mutta painikkeen tekstillä oli: nopeinta oli valita OK-tekstin sisältänyt painike. Katseen suunnan alueiden merkitseminen ei ollut kyllin tarkkaa, jotta kokeessa olisi selvinnyt, mihin käyttäjä katsoo ensin. Tilastollisesti merkitsevästi nopeinta kuitenkin oli suoriutua tehtävästä, jossa näkyvin vaihtoehto oli oikea vaihtoehto, riippumatta katsoiko käyttäjä vain tämän vaihtoehdon puolelle vai molemmille puolille dialogia, sekä kun valittavana oli positiivinen vaihtoehto dialogin oikealla puolella. Yllättävästi, ilman tehtävän luomaa ekologisesti validia kehystystä pelkkä komponentin näkyvyys ei ollut merkitsevä tekijä, vaan merkitsevää oli käyttöliittymäkomponentin teksti.This master's thesis investigates how the saliency of user interface components affect users when they choose between two options. Many services have moved online and they usually ask their users to accept web cookies that are either necessary for the functioning of the service or improve it. Users are enticed to operate to the advantage of the service provider by offering an attention-grabbing salient option for acceptance. For this thesis, software was developed, in which users were presented with three types of dialogues, with a difference in visibility between the two UI components. The user was offered two normal buttons to choose from, a normal button with a background-free button, or a normal button with a link. The experiment had 20 participants who were monitored using eye-tracking camera glasses, and the speed and accuracy of their tasks were measured using timestamps at the clicking of a button. The tasks were so easy that almost all participants were able to choose requested action even though the task was asked to be done as fast as possible. The layout of the buttons had no statistically significant effect on speed, but the text of the button had: the quickest was to select the button that contained the text OK. In the experiment, the marking of the areas of the direction of the gaze was not precise enough to determine where the user first looks. However, statistically significant the fastest was to complete the task where the most salient option was the correct option, regardless of whether the user looked at only this side or both sides of the dialogue, or those cases where the right answer was a positive option on the right side of the dialog. Surprisingly, without the ecologically valid framing created by the task, the mere visibility of the component was not a significant factor, but the text of the UI component was

Telecommunication Network Security

YesOur global age is practically defined by the ubiquity of the Internet; the worldwide interconnection of cyber networks that facilitates accessibility to virtually all ICT and other elements of critical infrastructural facilities, with a click of a button. This is regardless of the user’s location and state of equilibrium; whether static or mobile. However, such interconnectivity is not without security consequences. A telecommunication system is indeed a communication system with the distinguishing key word, the Greek tele-, which means "at a distance," to imply that the source and sink of the system are at some distance apart. Its purpose is to transfer information from some source to a distant user; the key concepts being information, transmission and distance. These would require a means, each, to send, convey and receive the information with safety and some degree of fidelity that is acceptable to both the source and the sink. Chapter K begins with an effort to conceptualise the telecommunication network security environment, using relevant ITU-T2* recommendations and terminologies for secure telecommunications. The chapter is primarily concerned with the security aspect of computer-mediated telecommunications. Telecommunications should not be seen as an isolated phenomenon; it is a critical resource for the functioning of cross-industrial businesses in connection with IT. Hence, just as information, data or a computer/local computer-based network must have appropriate level of security, so also a telecommunication network must have equivalent security measures; these may often be the same as or similar to those for other ICT resources, e.g., password management. In view of the forgoing, the chapter provides a brief coverage of the subject matter by first assessing the context of security and the threat-scape. This is followed by an assessment of telecommunication network security requirements; identification of threats to the systems, the conceivable counter or mitigating measures and their implementation techniques. These bring into focus various cryptographic/crypt analytical concepts, vis a vis social engineering/socio-crypt analytical techniques and password management. The chapter noted that the human factor is the most critical factor in the security system for at least three possible reasons; it is the weakest link, the only factor that exercises initiatives, as well as the factor that transcends all the other elements of the entire system. This underscores the significance of social 2*International Telecommunications Union - Telecommunication Standardisation Sector 12 engineering in every facet of security arrangement. It is also noted that password security could be enhanced, if a balance is struck between having enough rules to maintain good security and not having too many rules that would compel users to take evasive actions which would, in turn, compromise security. The chapter is of the view that network security is inversely proportional to its complexity. In addition to the traditional authentication techniques, the chapter gives a reasonable attention to locationbased authentication. The chapter concludes that security solutions have a technological component, but security is fundamentally a people problem. This is because a security system is only as strong as its weakest link, while the weakest link of any security system is the human infrastructure. A projection for the future of telecommunication network security postulates that, network security would continue to get worse unless there is a change in the prevailing practice of externality or vicarious liability in the computer/security industry; where consumers of security products, as opposed to producers, bear the cost of security ineffectiveness. It is suggested that all transmission devices be made GPS-compliant, with inherent capabilities for location-based mutual authentication. This could enhance the future of telecommunication security.Petroleum Technology Development Fun

Static analysis of unbounded structures in object-oriented programs

In this thesis we investigate different techniques and formalisms to address complexity introduced by unbounded structures in object-oriented programs. We give a representation of a weakest precondition calculus for abstract object creation in dynamic logic. Based on this calculus we define symbolic execution including abstract object creation. We investigate the complex behaviour introduced by multi-threading and give a formalism based on the transformation of multi-threaded reentrant call-graphs to thread automata and the application of context free language reachability to decide deadlock freedom of such programs. We give a formalisation of the observable interface behaviour of a concurrent, object-oriented language with futures and promises. The calculus captures the core of the Creol language and allows for a comparison with the concurrency model of thread-based, object-oriented languages like Java or C#. We give a technique to detect deadlock freedom for an Actor-like subset of the Creol language. LEI Universiteit LeidenThe work in this thesis has been carried out at the Christian-Albrechts--Universität zu Kiel, the Centrum Wiskunde & Informatica (CWI), and the Universiteit Leiden. The research was partially funded by the EU-project IST- 33826 Credo: Modeling and analysis of evolutionary structures for distributed services; the EU-project FP7-231620 HATS: Highly Adaptable and Trustworthy Software using Formal Methods; and the German-Norwegian DAAD-NWO exchange project Avabi (Automated validation for behavioral interfaces of asynchronous active objects).Algorithms and the Foundations of Software technolog

SAFETY CLIMATE AND AFTER-ACTION REVIEWS IN THE FIRE SERVICE

Research on safety climate has focused on supervisor attitudes and their relationship to the attitudes of their direct reports. This study examined the relationship of supervisor behaviors on direct report attitudes that in turn affect group level safety climate among firefighters. This study aggregated perceptions of supervisor trust, leader- member exchange, behavioral integrity, supervisor after action review behavior, and safety climate to the group level to examine the relationship between supervisor behaviors, direct report attitudes and group safety climate. This study found that supervisor trust, behavioral integrity, and supervisor after action review behaviors have a strong positive relationship to safety climate. Further, perceptions of trust partially mediate the relationship between supervisor after action review behaviors and group level safety climate. Future research ideas, theoretical advancements, and practical applications are discussed

“Tuna – Dolphin Forever?" The Development of the PPM Debate Related to Trade and Environment in the WTO

The Tuna-Dolphin disputes between the United States and Mexico have spanned almost three decades. They have shed light on the “PPM debate”, i.e. whether trade restrictions based on differences in process and production methods (PPMs) are justifiable under international trade rules. While a very strict approach against the use of PPM measures prevailed at the end of the GATT era, it has significantly evolved during the first two decades of the WTO. The Dispute Settlement Body eventually upheld a PPM “dolphin-safe” measure at the end of a particularly long judicial saga. The different Tuna-Dolphin reports show how environmental interests have gradually been integrated in WTO law and have influenced the interpretation of some of the core provisions of the GATT and the TBT Agreement (nondiscrimination obligations, general exceptions). These remarkable evolutions may be viewed as reflections of the objective of sustainable development mentioned in the WTO Agreement and as consequences of the judicialization of the multilateral trading system, which has allowed more legally sophisticated analyses based on the rule of law. They also illustrate efforts to foster the external legitimacy of the WTO, through greater sensitivity towards non-trade values. At the same time, the Tuna-Dolphin case law has become particularly complex, focusing on very fine technical details specific to the dispute, which has led to the risk of “never-ending story”. In this context, the search for legal security, coherence and efficient settlement of disputes may be the next challenge for WTO adjudicating bodies. At the same time, the use of PPM measures remains delicate and requires the assessment and balance of a variety of interests, including the specific interests of developing countries