Worst-Case Execution Time (WCET) estimates for programs are necessary when building real-time systems. They are used to ensure timely responses from interrupts, to guarantee the throughput of cyclic tasks, as input to scheduling and schedule analysis algorithms, and in many other circumstances. Traditionally, such estimates have been obtained either by measurements or labor-intensive manual analysis, which is both time consuming and error-prone. Static worst-case execution time analysis is a family of techniques that promise to quickly provide safe execution time estimates for real-time programs, simultaneously increasing system quality and decreasing the development cost. This thesis presents several contributions to the state-of-the-art in WCET analysis. We present an overall architecture for WCET analysis tools that provides a framework for implementing modules. Within the stable interfaces provided, modules can be independently replaced, making it easy to customize a tool for a particular target and perform performance-precision trade-offs. We have developed concrete techniques for analyzing and representing the timing behavior of programs running on pipelined processors. The representation and analysis is more powerful than previous approaches in that pipeline timing effects across more than pairs of instructions can be handled, and in that no assumptions are made about the program structure. The analysis algorithm relies on a trace-driven processor simulator instead of a special-purpose processor model. This allows us to use existing simulators to adapt the analysis to a new target platform, reducing the retargeting effort. We have defined a formal mathematical model of processor pipelines, which we use to investigate the properties of pipelines and WCET analysis. We prove several interesting properties of processors with in-order issue, such as the freedom from timing anomalies and the fundamental safety of WCET analysis for certain classes of pipelines. We have also constructed a number of examples that demonstrate that tight and safe WCET analysis for pipelined processors might not be as easy as once believed. Considering the link between the analysis methods and the real world, we discuss how to build accurate software models of processor hardware, and the conditions under which accuracy is achievable.

In this dissertation, we present two new sorts of computer sciencelogics. Many powerful logics exist today for reasoning about multi-agentsystems, but in most of these it is hard to reason about an infiniteor indeterminate number of agents. Also the naming schemes used inthe logics often lack expressiveness to name agents in an intuitiveway. To obtain a more expressive language for multi-agent reasoning and abetter naming scheme for agents, we introduce in the first part of thedissertation a family of logics called term-modal logics. A mainfeature of our logics is the use of modal operators indexed by theterms of the logics. Thus, one can quantify over variables occurringin modal operators. In term-modal logics agents can be represented byterms, and knowledge of agents is expressed with formulas within thescope of modal operators. This gives us a flexible and uniform language for reasoning about theagents themselves and their knowledge. We give examples of theexpressiveness of the languages and provide sequent-style andtableau-based proof systems for the logics. Furthermore, we giveproofs of soundness and completeness with respect to the possibleworld semantics. In the second part of the dissertation, we treat another problem inreasoning about multi-agent systems, namely the problem of informationupdating. We develop a dynamic logic of assignments with a scopingoperator instead of quantifiers. Function, relation symbols and logicvariables are all rigidly interpreted in our semantics, while programvariables are non-rigid. The scoping operator is used to distinguishbetween the value of a program variable before and after the executionof a program. We provide a tableau proof system for the logic. First, the system isproved complete without the star operator, and then with the staroperator using an omega rule. The full logic is shown to beundecidable, while some interesting fragments are decidable.

<p> Telepresence uses the latest video conferencing technology, with high definition video, surround sound audio, and specially constructed studios, to create a near face-to-face meeting experience. A Fortune 500 company which markets information technology has organizations distributed around the globe, and has extensive collaboration needs among those organizations. Having invested heavily in telepresence technology to assist in the collaboration, the company has experienced a broad range of use among departments, but some departments do not use it at all. The purpose of this research was to study the reasons for widely disparate levels of telepresence use. The research is based upon factors contained in the unified theory of acceptance and use of technology and assessed the impact of each upon the use of telepresence technology. The results of the research showed some factors affected telepresence acceptance and use while other factors had little or no effect. Underlying practices and conditions, such as the need to multi-task and to telecommute, impacted the factors. The research provided recommendations for assessing the likelihood of technology adoption before making investments, and for positively influencing adoption.</p>

<p> The purpose of the study was to address a gap in the scholarly literature about one of the factors related to the Global Digital Divide by expanding the body of generalizable knowledge about the relationship between national culture attitudes about information and communications technology (ICT) acceptance and use (A&amp;U) and national ICT use behavior across time. A quantitative quasi-experimental non-equivalent groups design was used as the basis for this research. Bivariate correlation analysis was conducted for 64 combinations of use behaviors and attitudes that were drawn from two secondary data sources; the first source was the World Values Survey database, and the second source the International Telecommunications Union ICT database. The study findings consistently suggest that there is a significant relationship between national culture attitudes about ICT A&amp;U and national ICT use behavior across time and within specific periods. Furthermore, the findings suggest that at any point in time, where national culture attitudes about ICT A&amp;U are the strongest, national ICT use behaviors will be the lowest, and where national culture attitudes about ICT A&amp;U are the most neutral, national ICT use behaviors will be the highest.</p>

<p> Information technology (IT) investment decision makers are required to process large volumes of complex data. An existing body of knowledge relevant to IT portfolio management (PfM), decision analysis, visual comprehension of large volumes of information, and IT investment decision making suggest Multi-Criteria Decision Making (MCDM) and hypervariate display techniques can reduce cognitive load and improve decision confidence in IT PfM decisions. This dissertation investigates improving the decision confidence by reducing cognitive burden of the decision maker through greater comprehension of relevant decision information. Decision makers from across the federal government were presented with actual federal IT portfolio project lifecycle costs and durations using hypervariate displays to better comprehend IT portfolio information more quickly and make more confident decisions. Other information economics attributes were randomized for IT portfolio projects to generate Balanced Scorecard (BSC) values to support MCDM decision aids focused on IT investment alignment with specific business objectives and constraints. Both quantitative and qualitative measures of participant comprehension, confidence, and efficiency were measured to assess hypervariate display treatment and then MCDM decision aid treatment effectiveness. Morae Recorder Autopilot guided participants through scenario tasks and collected study data without researcher intervention for analysis using Morae Manager. Results showed improved comprehension and decision confidence using hypervariate displays of federal IT portfolio information over the standard displays. Both quantitative and qualitative data showed significant differences in accomplishment of assigned IT portfolio management tasks and increased confidence in decisions. MCDM techniques, incorporating IT BSC, Monte Carlo simulation, and optimization algorithms to provide cost, value, and risk optimized portfolios improved decision making efficiency. Participants did not find improved quality and reduced uncertainty from optimized IT portfolio information. However, on average participants were satisfied and confident with the portfolio optimizations. Improved and efficient methods of delivering and visualizing IT portfolio information can reduce decision maker cognitive load, improve comprehension efficiency, and improve decision making confidence. Study results contribute to knowledge in the area of comprehension and decision making cognitive processes, and demonstrate important linkages between Human-Computer Interaction (HCI) and Decision Support Systems (DSS) to support IT PfM decision making.</p>

<p> The purpose of this case study was to determine the nature of conversations that occur within an organizational microblog and compare them to traditional informal conversations. Since informal conversations are closely associated with reaction to change, this study explored how organizational microblog conversations may be understood to affect outcomes resulting from organizational change. </p><p> A sequential transformative design was used to collect four sources of evidence (Yin, 2009): microblog responses for 90 days; focus groups at the beginning, middle, and end of the 90-day period; pre and post organizational culture assessment surveys; and on-site participant observation. The site selected for this study was the healthcare innovation section of a nonprofit science, technology, and strategy organization located in Northern Virginia. </p><p> Overall, in HCD the rate of microblog messages was low, constrained by employee fear (Ford et al., 2008), in a working environment characterized by top-down leadership (Meyer &amp; Davis, 2003), organizational silence (Morrison &amp; Milliken, 2000), and resistance (Ford &amp; Ford, 1995; Ford et al., 2002, 2008; Marshak, 2006; Piderit, 2000; Weick &amp; Quinn, 1999) expressed often by ambivalence (Piderit, 2000). Eight conclusions emerged from the findings of this study: the suppressed and constrained nature of microblog conversations, the presence of resistance, the use of power, the expression of emotion, the limited impact of gender on microblog use, microblog participation and organizational controls, organizational change as continuous and multidimensional, and mixed views on power and the benefits of informal conversation in the workplace. The phenomenon of counter-resistance (Karreman &amp; Alvesson, 2009) served as an explanation for study findings associated with participants' compliance to power, their unwillingness to openly express resistance, and the inhibition of emotion and affect at work. </p><p> Given the security requirements associated with enterprise computer technology, the background conversations of "complacency, resignation and cynicism" (Ford et al., 2002) may never surface in a microblog. However, with employees' geographical dispersion and increased telecommuting options, the microblog may be a perfect tool for increased social interaction and self-disclosure within the organization while concurrently serving as an intraorganizational knowledge management system.</p>

<p> The global financial system appears to be heading for a major financial crisis. This crisis is being driven by a growing global debt. This crisis is not limited to nations that are heavily in debt such as Greece, Spain, Portugal, Ireland, Italy or Cyprus but to such others as the United States. While there has been a great deal of emphasis on debt, there are many other issues. In many cases, the underlying causes of this potential crisis are very complex. As this dissertation will show, it is the complexity of these causes and their interrelationships, coupled with a lack of a global financial management system that may be the real culprit in the potentially impending global financial crisis. </p><p> One very important aspect of these potential crises is the state of the world reserve currency and how it is managed. The concept of reserve currencies is widely recognized and these currencies are often used for international transactions. There is a very long history of the concept of a reserve currency. This history involves a combination of economic and political powers, real or perceived, that may influence global reserve currencies. </p><p> Recent years have witnessed a tremendous growth in information and communication systems that facilitate the design and implementation of complex inter-enterprise processes. The basic hypothesis of this dissertation is that an appropriately structured global reserve currency, based on use of an information and knowledge management system, can provide stability to currencies, whereas an unmanaged single or unstructured group of currencies will not provide currency stability. The proposed Information and Knowledge Architectures for System Management of a Global Reserve Currency (IKASM-GRC) can provide a system and methodology which can stabilize a reserve currency.</p>

<p> This qualitative, exploratory, normative study examined the security and privacy of location based services in mobile applications. This study explored risk, and controls to implement privacy and security. This study was addressed using components of the FIPS Risk Management Framework. This study found that risk to location information was considered <i> high</i> and the study provided suggested controls for security and privacy. </p>

<p>Users are increasingly expected to manage complex privacy settings in their normal online interactions. From shopping to social networks, users make decisions about sharing their personal information with corporations and contacts, frequently with little assistance. Current solutions require consumers to read long documents or go out of their way to manage complex settings buried deep in management interfaces, all of which lead to little or no actual control. </p><p> The goal of this work is to help people cope with the shifting privacy landscape. While our work looks at many aspects of how users make decisions regarding their privacy, this dissertation focuses on two specific areas: the current state of web privacy policies and mobile phone application permissions. We explored consumers' current understandings of privacy in these domains, and then used that knowledge to iteratively design and test more comprehensible information displays. </p><p> These prototyped information displays should not be seen as final commercially-ready solutions, but as examples of privacy notices that can help users think about, cope with, and make decisions regarding their data privacy. We conclude with a series of design suggestions motivated by our findings. </p><p> Keywords: privacy, notice, usability, user interfaces, security, mobile, policy, P3P, HCI, information design. </p>

No description available.