Sharing economy-based on-demand peer-to-peer tutoring and resource sharing

The sharing economy is a socio-economic ecosystem built around the sharing of human and physical resources. This is considered to be a new and alternate socio-economic system which is currently in its early stages and has tremendous potential. The sharing economy combines the need to direct demand towards supply by adding the point of view of collaboration based on the social networks and preferences of various entities involved. This is based on the economic model of Collaborative Consumption in which participants share access to resources rather than having individual ownership over them. We propose the novel idea of a sharing economy-based model for knowledge sharing amongst peers in a classroom setting. Students often find themselves stuck on trivial implementation details like syntax, best practices and which tools to use. Many times, help is difficult to find, even though the solution might be known to one of the student's peers. Moreover, many large classes do not have enough teaching assistants to help out students and the use of such a platform can be useful to offload simple questions within the classroom itself, saving office hours for more complex questions. This, coupled with the benefits of a collaborative learning environment for students, has motivated us towards the development of an on-demand peer-to-peer tutoring and knowledge sharing platform. Such a platform can also help us understand how different incentive mechanisms motivate people to share knowledge: Are people motivated by social reputation or money? We develop an Android application called "Quet" which can be used by students to request help from their peers for questions related to their coursework on-demand. Preliminary observations show that an application like Quet is useful; and we wish to deploy this in multiple courses in subsequent semesters to realize its full potential and utility to students and instructors alike

A Robust and Optimal Multidisciplinary Approach For Space Systems Conceptual Design

L'abstract è presente nell'allegato / the abstract is in the attachmen

Simulated penetration testing and mitigation analysis

Da Unternehmensnetzwerke und Internetdienste stetig komplexer werden, wird es immer schwieriger, installierte Programme, Schwachstellen und Sicherheitsprotokolle zu überblicken. Die Idee hinter simuliertem Penetrationstesten ist es, Informationen über ein Netzwerk in ein formales Modell zu transferiern und darin einen Angreifer zu simulieren. Diesem Modell fügen wir einen Verteidiger hinzu, der mittels eigener Aktionen versucht, die Fähigkeiten des Angreifers zu minimieren. Dieses zwei-Spieler Handlungsplanungsproblem nennen wir Stackelberg planning. Ziel ist es, Administratoren, Penetrationstestern und der Führungsebene dabei zu helfen, die Schwachstellen großer Netzwerke zu identifizieren und kosteneffiziente Gegenmaßnahmen vorzuschlagen. Wir schaffen in dieser Dissertation erstens die formalen und algorithmischen Grundlagen von Stackelberg planning. Indem wir dabei auf klassischen Planungsproblemen aufbauen, können wir von gut erforschten Heuristiken und anderen Techniken zur Analysebeschleunigung, z.B. symbolischer Suche, profitieren. Zweitens entwerfen wir einen Formalismus für Privilegien-Eskalation und demonstrieren die Anwendbarkeit unserer Simulation auf lokale Computernetzwerke. Drittens wenden wir unsere Simulation auf internetweite Szenarien an und untersuchen die Robustheit sowohl der E-Mail-Infrastruktur als auch von Webseiten. Viertens ermöglichen wir mittels webbasierter Benutzeroberflächen den leichten Zugang zu unseren Tools und Analyseergebnissen.As corporate networks and Internet services are becoming increasingly more complex, it is hard to keep an overview over all deployed software, their potential vulnerabilities, and all existing security protocols. Simulated penetration testing was proposed to extend regular penetration testing by transferring gathered information about a network into a formal model and simulate an attacker in this model. Having a formal model of a network enables us to add a defender trying to mitigate the capabilities of the attacker with their own actions. We name this two-player planning task Stackelberg planning. The goal behind this is to help administrators, penetration testing consultants, and the management level at finding weak spots of large computer infrastructure and suggesting cost-effective mitigations to lower the security risk. In this thesis, we first lay the formal and algorithmic foundations for Stackelberg planning tasks. By building it in a classical planning framework, we can benefit from well-studied heuristics, pruning techniques, and other approaches to speed up the search, for example symbolic search. Second, we design a theory for privilege escalation and demonstrate the applicability of our framework to local computer networks. Third, we apply our framework to Internet-wide scenarios by investigating the robustness of both the email infrastructure and the web. Fourth, we make our findings and our toolchain easily accessible via web-based user interfaces

Structure and agency in the economics of public policy for TB control

Globally, Tuberculosis remains a devastating disease, despite the availability of treatment. The disease is associated with poverty, and those with the disease incur a high cost of accessing care, while simultaneously experiencing income loss due to a loss in productivity. A key challenge in TB programmes remains the accurate diagnosis of the disease, especially in people who are HIV positive. Diagnosing TB can be very resource intensive and the accuracy of diagnosis is dependent on a range of disease, health service organisation and provider behaviour factors. This thesis seeks to enhance understanding of how the behaviour of healthcare workers mediates the value of TB diagnostic algorithms, and how this may affect the costs, outcomes as well as the economic burden associated with the disease in South Africa. The work presented is based on empirical work done alongside a pragmatic cluster randomized control trial. Empirically, it examines the longitudinal economic burden of TB diagnosis and treatment in South Africa. The discrepancies between the time at which patients incur the greatest cost and income loss, and the available social protection are highlighted. Based on empirical work, a purpose-built state-transition mathematical model of TB diagnosis and treatment was developed to estimate the cost-effectiveness, from the perspective of the health service and the patient, of health systems interventions to strengthen TB diagnosis. Recognising healthcare workers as those who ultimately express policies, the behaviour of healthcare workers was included in the cost-effectiveness analysis by 1) using data from a pragmatic trial reflecting routine practice and clinical decision-making at the time of the study; 2) developing a conceptual framework of the relationship between behaviour at decision points and disease outcomes; and 3) investigating how these interactions may influence the value of the diagnostic algorithm. Possible public policy levers to improve TB diagnosis in healthcare facilities, as well as the potential mediators of costs and effects were explored. The thesis concludes with recommendations for further methodological work to expand on the approach explored in this thesis to improve how heterogeneity in estimates of cost-effectiveness is presented to decision-makers

Supporting Evolution and Maintenance of android Apps

Mobile developers and testers face a number of emerging challenges. These include rapid platform evolution and API instability; issues in bug reporting and reproduction involving complex multitouch gestures; platform fragmentation; the impact of reviews and ratings on the success of their apps; management of crowd-sourced requirements; continuous pressure from the market for frequent releases; lack of effective and usable testing tools; and limited computational resources for handheld devices. Traditional and contemporary methods in software evolution and maintenance were not designed for these types of challenges; therefore, a set of studies and a new toolbox of techniques for mobile development are required to analyze current challenges and propose new solutions. This dissertation presents a set of empirical studies, as well as solutions for some of the key challenges when evolving and maintaining android apps. In particular, we analyzed key challenges experienced by practitioners and open issues in the mobile development community such as (i) android API instability, (ii) performance optimizations, (iii) automatic GUI testing, and (iv) energy consumption. When carrying out the studies, we relied on qualitative and quantitative analyses to understand the phenomena on a large scale by considering evidence extracted from software repositories and the opinions of open-source mobile developers. From the empirical studies, we identified that dynamic analysis is a relevant method for several evolution and maintenance tasks, in particular, because of the need of practitioners to execute/validate the apps on a diverse set of platforms (i.e., device and OS) and under pressure for continuous delivery. Therefore, we designed and implemented an extensible infrastructure that enables large-scale automatic execution of android apps to support different evolution and maintenance tasks (e.g., testing and energy optimization). In addition to the infrastructure we present a taxonomy of issues, single solutions to the issues, and guidelines to enable large execution of android apps. Finally, we devised novel approaches aimed at supporting testing and energy optimization of mobile apps (two key challenges in evolution and maintenance of android apps). First, we propose a novel hybrid approach for automatic GUI-based testing of apps that is able to generate (un)natural test sequences by mining real applications usages and learning statistical models that represent the GUI interactions. In addition, we propose a multi-objective approach for optimizing the energy consumption of GUIs in android apps that is able to generate visually appealing color compositions, while reducing the energy consumption and keeping a design concept close to the original

The Reality and Masquerade behind Bargaining over Welfare Pie Sizing, Delivery and Slicing.

The present analysis addresses the apparently critical issue of circulation of wealth in society. Three actors play the game of welfare-related taxation. The first actor, in the role of Negotiator No.1, stands up for citizens’ legal and moral rights to primary needs. The second actor, in the role of Negotiator No.2, proceeds in response to public will for the provision and delivery of public goods. Quite the opposite, the third actor, hereinafter named the Voter, who represents the taxpayers, prefers personal consumption to moral understanding and public activity. In fact, backed by electoral maneuvering, the Voter emanates a risk to break down negotiations. The result of the simulation provides an evidence for the claim that a 50% median income is close enough to be considered a realistic choice of poverty line within the variety or rules of the alternating-offers bargaining game and conditions for unanimous consent of voter-citizens.bargaining; policy; public goods; simulation; taxation; voting

The total assessment profile, volume 1

A methodology is described for the evaluation of societal impacts associated with the implementation of a new technology. Theoretical foundations for the methodology, called the total assessment profile, are established from both the economic and social science perspectives. The procedure provides for accountability of nonquantifiable factors and measures through the use of a comparative value matrix by assessing the impacts of the technology on the value system of the society

Simulation of automated negotiation

Durch die Automatisierung von Verhandlungen sollen bessere Verhandlungsergebnisse erzielt werden können als bei Verhandlungen zwischen Menschen und neue Koordinationsformen für autonome Agentensysteme ermöglicht werden. Diese Arbeit beschäftigt sich mit der Simulation solcher Systeme für automatisierte Verhandlungen, da operative Systeme zur Zeit noch nicht verfügbar sind. Die Arbeit basiert auf einer Erhebung und Diskussion der aktuellen Literatur im Bereich der Simulation automatisierter Verhandlungen. Existierende Ansätze weisen einige Unzulänglichkeiten bezüglich deren praktischer Umsetzbarkeit in einer offenen Umgebung wie dem Internet auf, wo automatisierte Verhandlungen nicht nur sehr schnell durchgeführt werden sondern sich auch Software-Agenten und Verhandlungsprobleme ändern können. Diese Defizite thematisierend werden Verhandlungssysteme für automatisierte Verhandlungen vorgeschlagen. Diese bestehen zum einen aus Software-Agenten, die generische Angebots- und Konzessionsstratgien verfolgen, zum anderen aus Interaktionsprotokollen, die es Agenten erlauben ihre Strategien vorübergehend oder permanent auszusetzen. Ergebnisse der Simulation dieser Systeme, mit Verhandlungsproblemen aus Verhandlungsexperimenten mit menschlichen Probanden als Input, werden für unterschiedliche Ergebnisdimensionen -- Übereinkunftshäufigkeit, Fairness, individuelle und kollektive Effizienz -- zwischen Systemen und auch mit den Ergebnissen der Experimente verglichen. Trotz fundamentaler Zielkonflikte zwischen den einzelnen Ergebnisdimensionen erzielen einige Systeme konsistent bessere Ergebnisse sowohl im Systemvergleich als auch verglichen mit den Ergebnissen der Experimente. Diese Systeme bestehen aus Software-Agenten die systematisch Angebote mit monoton abnehmendem Nutzen unterbreiten und erste Konzessionensschritte tätigen solange der Opponent bisherige Konzessionen erwidert hat. Das verwendete Interaktionsprotokoll zeichnet sich dadurch aus, dass es den Agenten erlaubt ungünstige Angebote zurückzuweisen und damit neue Angebote des Opponenten einzufordern, durch diese Unterbrechung der eigenen Angebotsstrategie können ungünstige Verhandlungsergebnisse vermieden werden.Automated negotiation is argued to improve negotiation outcomes by replacing humans and to enable coordination in autonomous systems. As operative systems do not yet exist scholars rely on simulations to evaluate potential systems for automated negotiation. This dissertation reviews the state of the art literature on simulation of automated negotiation along its main components - negotiation problem, interaction protocol, and software agents. Deficiencies of existing approaches concerning the practical application in an open environment as the Internet - where automated negotiation proceeds fast, with changing opponents, and for various negotiation problems - are identified. To address these deficiencies we develop and simulate automated negotiation systems, consisting of software agents that follow generic offer generation and concession strategies and protocols that allow these agents to interrupt their strategy to avoid exploitation and unfavorable agreements. Outcomes of simulation runs are compared across systems and to human negotiation along various outcome dimensions - proportion of agreements, dyadic and individual performance, and fairness - for various negotiation problems derived from negotiation experiments with human subjects. Though there exist trade-offs between the different outcome dimensions, systems consisting of software agents, that systematically propose offers of monotonically decreasing utility and make first concession steps if the opponent reciprocated previous concessions, and an interaction protocol that enables to reject unfavorable offers - without immediately aborting negotiations - in order to elicit new offers from the opponent, performed best. These systems performed very well in all outcome dimensions when compared with other systems and were the only that outperformed negotiation between humans in all dimensions

The Roles of Corporate IT Infastructure and their Impact on IS Effectiveness

In the strategic alignment model of Henderson and Venkatraman (1993) [1] IT infrastructure has an important but only implicitly defined role. According to evolving literature, IT infrastructure serves many different purposes in large companies. We outline the main missions (roles) of the corporate-wide IT infrastructure and its contribution to IS effectiveness and study the relationship of IT infrastructure with alignment processes and strategic integration. Our empirical tests with data from almost one hundred large companies resulted in three IT infrastructure roles, which reflect the IS communality, strategic, and flexibility dimensions of the corporate-wide IT infrastructure. The roles were not symmetrically related to the IS effectiveness and alignment perspectives. IT infrastructure roles had a significant interplay with strategic integration in improving IS effectiveness. However, the interplay of IT infrastructure roles with alignment perspectives had only marginal effects. Implications of the results for research and practice are discussed

Assessment of joint inventory replenishment: a cooperative games approach

This research deals with the design of a logistics strategy with a collaborative approach between non-competing companies, who through joint coordination of the replenishment of their inventories reduce their costs thanks to the exploitation of economies of scale. The collaboration scope includes sharing logistic resources with limited capacities; transport units, warehouses, and management processes. These elements conform a novel extension of the Joint Replenishment Problem (JRP) named the Schochastic Collaborative Joint replenishment Problem (S-CJRP). The introduction of this model helps to increase practical elements into the inventory replenishment problem and to assess to what extent collaboration in inventory replenishment and logistics resources sharing might reduce the inventory costs. Overall, results showed that the proposed model could be a viable alternative to reduce logistics costs and demonstrated how the model can be a financially preferred alternative than individual investments to leverage resources capacity expansions. Furthermore, for a practical instance, the work shows the potential of JRP models to help decision-makers to better understand the impacts of fleet renewal and inventory replenishment decisions over the cost and CO2 emissions.DoctoradoDoctor en Ingeniería Industria