This paper investigates how people return to information in a dynamic information environment. For example, a person might want to return to Web content via a link encountered earlier on a Web page, only to learn that the link has since been removed. Changes can benefit users by providing new information, but they hinder returning to previously viewed information. The observational study presented here analyzed instances, collected via a Web search, where people expressed difficulty re-finding information because of changes to the information or its environment. A number of interesting observations arose from this analysis, including that the path originally taken to get to the information target appeared important in its re-retrieval, whereas, surprisingly, the temporal aspects of when the information was seen before were not. While people expressed frustration when problems arose, an explanation of why the change had occurred was often sufficient to allay that frustration, even in the absence of a solution. The implications of these observations for systems that support re-finding in dynamic environments are discussed.

This paper investigates how people return to information in a dynamic information environment. For example, a person might want to return to Web content via a link encountered earlier on a Web page, only to learn that the link has since been removed. Changes can benefit users by providing new information, but they hinder returning to previously viewed information. The observational study presented here analyzed instances, collected via a Web search, where people expressed difficulty re-finding information because of changes to the information or its environment. A number of interesting observations arose from this analysis, including that the path originally taken to get to the information target appeared important in its re-retrieval, whereas, surprisingly, the temporal aspects of when the information was seen before were not. While people expressed frustration when problems arose, an explanation of why the change had occurred was often sufficient to allay that frustration, even in the absence of a solution. The implications of these observations for systems that support re-finding in dynamic environments are discussed.

<p>Information technology (IT) is becoming the primary factordetermining the survival of most organizations. The differenttypes of systems and the wide range of objectives suggest thatdiverse evaluation methods are needed. There is a critical needfor a new approach to managing IT investments, and solving theinformation paradox should be a business imperative for allmanagers today.</p><p>Evaluating IT investments introduces different types ofproblems that investment in traditional assets does notconsider. The focal point shifts from measuring hard andquantifiable benefits that appear on a firm’s incomestatement to measuring soft, diffuse, and qualitativeimpact.</p><p>The decision to acquire new information technology poses anumber of serious evaluation problems for managers because theavailable methods for IT investment evaluation are mostlystatic and they do not consider dynamism in decision-makingprocesses.</p><p>Common problems with the methods for evaluating ITinvestments are related to their inability to take account ofthe full range of potential benefits. There is a gap betweentheory and practice in relation to the use of any method formaking decisions and for continuous evaluation of ITinvestments.</p><p>This thesis presents a new approach to evaluating benefitsof IT investments in a dynamic way, an approach consisting of acombination of dynamic information workflow models and businessprocess simulation techniques. The proposed approach givesmanagers and organizations the possibility of implementingother models for measuring different metrics and aspects of ITinvestments.</p><p>A dynamic information workflow model of an electric utilityandsimulation essays are presented in order to show how theproposed approach is applied. The performance measure selectedfor running experiments was efficiency, which was characterizedby the following selected performance indicators: cycle time,resource utilization, and activity costs. Empirical data wascollected from case studies of different utilities in CentralAmerican countries.</p><p><b>Key words:</b>Business Process Modeling and Simulation,Evaluating IT Investments, Dynamic Information Workflow Model,Electric Utilities.</p>

In order to attract the attention of users current online shopping environments often involve the use of dynamic display changes such as animation, flashing or rotating text, and pop-up boxes. While there is some experimental evidence that supports the effectiveness of such changes for the purpose of capturing attention, such changes might also distract the user and hinder task performance. Thus, a key usability challenge for the designers of such environments involves balancing the need to attract attention with the desire to minimize any interruption of the performance of users. To date there is very little systematic investigation of the influence of display changes on consumers¡¦ attention and decisions during the browsing of online shopping web sites. The main goal of the present experiments was to research factors that might be important in determining the influence of such display changes. To accomplish that experimental tasks were created that resembled some aspects of the visual decision process and dynamic changes that occur during online shopping. However, in order to permit greater experimental control, the information environment used in the present tasks was substantially simplified as compared to online environments. Specifically, in 3 experiments, participants¡¦ eye movements were monitored while they chose between 2 alternatives, each represented by a set of visual images, with one set placed on the top of the screen and the other on the bottom. Immediately prior to this decision participants performed one or more binary decisions based on subsets of these images. On some trials, images were spatially swapped in the display presented during the final decision as compared to a prior presentation. Across experiments, we manipulated the relevance of the change to task performance as well as the recency of the information that was modified. By analyzing behavioral and eye movement measures, we documented evidence that participants flexibly and effectively accommodated to a variety of display changes. However, there was cost associated with display changes in the form of longer viewing times. In addition, task relevant changes and changes to recently viewed information were generally more disruptive. We discuss the implications of the present findings for the design of online shopping web sites and for future research that would attempt to generalize the present findings to more complex and more realistic online environments.

Android has been steadily gaining popularity ever since its launch in 2008. One of the major factors for this is the easy availability of a large variety of apps. They range from simple apps such as calculator apps to apps which can help people maintain their schedules and thus man-age many aspects of their lives. In addition, a lot of free apps are available to the user thanks to the power of in-app purchases and advertisements. However, these also raise many security concerns. Apps are privy to a lot of private information regarding the user, such as his contacts, location, etc. It is essential to ascertain that apps do not leak such information to untrustworthy entities. In order to solve this problem, there have been many static and dynamic analyses which aim to track private data accessed or generated by the app to its destination. Such analyses are commonly known as Information Flow analyses. Dynamic analysis techniques, such as TaintDroid, tracks private information and alerts the user when it is accessed by speci c API calls. However, they do not track the path taken by the information, which can be useful in debugging and validation scenarios. The first key contribution of this thesis is a model to perform dynamic information ow analysis, inspired by FlowDroid and TaintDroid, which can retain path information of sensitive data in an efficient manner. The model instruments the app and uses path-edges to track the information flows during a dynamic run. We describe the data structure and transfer functions used, and the reasons for its design based on the challenges posed by the Android programming model and efficiency requirements. The second key contribution is the capability to trace the path taken by the sensitive information based on the information obtained during the analysis, as well as the capability to compliment static analyses such as FlowDroid with the output of this analysis. The tests conducted on the implemented model using DroidBench and GeekBench 3 show the precision and soundness of the analysis, and a performance overhead of 25% while real-world apps show negligible lag. All leaks seen in DroidBench where successfully tracked and were verified to be true positives. We tested the model on 10 real-world apps where we find on average about 16.4% of the total path-edges found by FlowDroid.

Information technology (IT) is becoming the primary factordetermining the survival of most organizations. The differenttypes of systems and the wide range of objectives suggest thatdiverse evaluation methods are needed. There is a critical needfor a new approach to managing IT investments, and solving theinformation paradox should be a business imperative for allmanagers today. Evaluating IT investments introduces different types ofproblems that investment in traditional assets does notconsider. The focal point shifts from measuring hard andquantifiable benefits that appear on a firm’s incomestatement to measuring soft, diffuse, and qualitativeimpact. The decision to acquire new information technology poses anumber of serious evaluation problems for managers because theavailable methods for IT investment evaluation are mostlystatic and they do not consider dynamism in decision-makingprocesses. Common problems with the methods for evaluating ITinvestments are related to their inability to take account ofthe full range of potential benefits. There is a gap betweentheory and practice in relation to the use of any method formaking decisions and for continuous evaluation of ITinvestments. This thesis presents a new approach to evaluating benefitsof IT investments in a dynamic way, an approach consisting of acombination of dynamic information workflow models and businessprocess simulation techniques. The proposed approach givesmanagers and organizations the possibility of implementingother models for measuring different metrics and aspects of ITinvestments. A dynamic information workflow model of an electric utilityandsimulation essays are presented in order to show how theproposed approach is applied. The performance measure selectedfor running experiments was efficiency, which was characterizedby the following selected performance indicators: cycle time,resource utilization, and activity costs. Empirical data wascollected from case studies of different utilities in CentralAmerican countries. <b>Key words:</b>Business Process Modeling and Simulation,Evaluating IT Investments, Dynamic Information Workflow Model,Electric Utilities. / NR 20140805

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Les flux d’information sont des transferts d’information entre les objets d’un environnement donné. À l’échelle du système, pour toute information appartenant à une application donnée, les flux impliquant cette information décrivent comment l’application propage ses données dans le système et l’ensemble de ces flux peut ainsi être considéré comme un profil comportemental de l’application. À cause du nombre croissant d’applications malveillantes, il est devenu nécessaire d’explorer des nouvelles techniques permettant de faciliter voir automatiser l’analyse et la détection de malware. Dans cette thèse, nous proposons ainsi une méthode pour caractériser et détecter les malware Android en nous basant sur les flux d’information qu’ils causent dans le système. Cette méthode repose sur deux autres contributions de la thèse : AndroBlare, la version Android d’un moniteur de flux d’information du nom de Blare, et les graphes de flux système, une structure de donnée représentant de manière compacte et humainement compréhensible les flux d’information observés. Nous avons évalué avec succès notre approche en construisant le profil de 4 malware différents et avons montré que ces profils permettaient de détecter l’exécution d’applications infectées par les malware dont on a un profil. / : Information flows are information exchanges between objects in a given environment. At system level, information flows involving data belonging to a given application describe how this application disseminates its data in the system and can be considered as behaviour based profile of the application. Because of the increasing number of Android malware, there is an urgent need to explore new approaches to analyse and detect Android malware. In this thesis, we thus propose an approach to characterize and detect Android malware based on information flows they cause in the system. This approach leverages two other contributions of the thesis which are AndroBlare, the Android version of an information flow monitor named Blare, and the system flow graph, a data structure to represent in a compact and human readable way the information flows observed by AndroBlare. We successfully evaluated our approach by building the profile of 4 different malware and showed that these profiles permitted to detect the execution of applications infected by malware for which we have computed a profile.

Digitaliseringen av samhället sker allt snabbare, men till skillnad från de flesta andra branscher så sker digitaliseringen av byggbranschen långsamt. Fastighetsförvaltningen är den del av branschen som ligger mest efter när det kommer till digitalisering. På grund av det har ett informationsgap uppstått mellan projekteringen och förvaltningen. En lösning för att binda samman projekteringens informationsrikedom med förvaltningen kan vara digitala tvillingar. Syftet med denna studie var att bidra till en ökad förståelse kring vad en digital tvilling är och att ge en bättre bild av hur en digital tvilling kan skapas samt hur den kan användas i förvaltningsskedet. Målet var att ta fram en BIM-modell som ska kunna ligga till grund för en digital tvilling som kan användas inom förvaltningen. Den metod som valdes för att undersöka problemet är modellering, där första steget var att ta fram statisk information kring den aktuella fastigheten. Sedan modellerades byggnaden och slutligen tillfördes dynamisk information via en molnbaserad plattform. För modelleringen av byggnaden användes programvaran Autodesk Revit 2023. För att sammanlänka 3D-modellen med den dynamiska informationen användes plattformen Twinfinity. I denna studie har en BIM-modell skapats som utgör en virtuell representation av en verklig fastighet. Relevant statisk och dynamisk information kring fastigheten samlades in och kopplades till den virtuella modellen. Den virtuella modellen som togs fram i denna studie kan per definition inte kallas för en digital tvilling, men kan med vidare arbete utvecklas till en digital tvilling. Den framtagna modellen bör ses som ett bra exempel på hur fastighetsdata kan kopplas till en BIM-modell och på hur informationen kan visualiseras på ett enkelt och lättförståeligt sätt.  Resultatet visar att implementering av digitala modeller i fastighetsförvaltningen kan generera fördelar. En digital modell ger fastighetsförvaltaren god kontroll och förståelse kring fastigheten, dess utseende, vad den innehåller och framförallt storlek på ytor och rum. Modellen skapar också en plattform där all information kring fastigheten kan samlas på ett och samma ställe och där den är lättillgänglig för alla inom organisationen då den är molnbaserad.  I dagsläget råder dock en ovisshet kring vad en digital tvilling är på grund av att det saknas en branschgemensam definition av begreppet, vilket kan leda till missförstånd och missuppfattningar. Vidare nås slutsatsen att det är svårare att skapa en informationsrik digital tvilling för en redan befintlig byggnad jämfört med nyproduktion med avseende på statisk information. Vid nyproduktion är det möjligt att ta tillvara på all den information som genereras under projekteringen och överföra den direkt till den digitala tvillingen genom en obruten informationskedja, vilket gör att informationsgapet mellan projektering och förvaltning undviks. Vad gäller dynamisk information råder däremot ingen skillnad i informationsrikedom i den digitala tvillingen för redan befintliga byggnader jämfört med nyproduktion. / Swedish property management is slow to adapt to the increasing digitalization in society. A tool to help the industry become more digitized is digital twins. The aim of this study is to contribute to an increased understanding of what a digital twin is and to give a better picture of how a digital twin can be produced for property management. The goal is to develop a BIM-model that can form the basis of a digital twin that can be used in property management. The method used to investigate the problem is by modelling an existing building that will be provided with static and dynamic information. The result shows that it is possible to produce a BIM-model relatively easily which can form the basis of a digital twin. The conclusion is that digital models create several advantages for the management, it creates good control and understanding of the property and gathers all information in one place. Currently, there is uncertainty about what a digital twin is due to the lack of an industry-wide definition of the term, which leads to misunderstandings and misconceptions. Lastly, creating a digital twin for an existing property can be problematic as the static information that the digital twin can contain is limited by the amount of information the property manager possesses, as well as the information that can be obtained through a physical examination of the building.

Computer security and privacy are becoming extremely important nowadays. The task of protecting computer systems from malicious attacks and potential subsequent catastrophic losses is, however, challenged by the ever increasing complexity and size of modern hardware and software design. We propose several methods to improve computer security and privacy from architectural point of view. They provide strong protection as well as performance efficiency. In our first approach, we propose a new dynamic information flow method to protect systems from popular software attacks such as buffer overflow and format string attacks. In our second approach, we propose to deploy encryption schemes to protect the privacy of an emerging non-volatile main memory technology - phase change memory (PCM). The negative impact of the encryption schemes on PCM lifetime is evaluated and new methods including a new encryption counter scheme and an efficient error correct code (ECC) management are proposed to improve PCM lifetime. In our third approach, we deconstruct two previously proposed secure cache designs against software data-cache-based side channel attacks and demonstrate their weaknesses. We propose three hardware-software integrated approaches as secure protections against those data cache attacks. Also we propose to apply them to protect instruction caches from similar threats. Furthermore, we propose a simple change to the update policy of Branch Target Buffer (BTB) to defend against BTB attacks. Our experiments show that our proposed schemes are both security effective and performance efficient.