InfoInternet for Education in the Global South: A Study of Applications Enabled by Free Information-only Internet Access in Technologically Disadvantaged Areas (authors' version)

This paper summarises our work on studying educational applications enabled by the introduction of a new information layer called InfoInternet. This is an initiative to facilitate affordable access to internet based information in communities with network scarcity or economic problems from the Global South. InfoInternet develops both networking solutions as well as business and social models, together with actors like mobile operators and government organisations. In this paper we identify and describe characteristics of educational applications, their specific users, and learning environment. We are interested in applications that make the adoption of Internet faster, cheaper, and wider in such communities. When developing new applications (or adopting existing ones) for such constrained environments, this work acts as initial guidelines prior to field studies.Comment: 16 pages, 1 figure, under review for a journal since March 201

Studying the Transfer of Biases from Programmers to Programs

It is generally agreed that one origin of machine bias is resulting from characteristics within the dataset on which the algorithms are trained, i.e., the data does not warrant a generalized inference. We, however, hypothesize that a different `mechanism', hitherto not articulated in the literature, may also be responsible for machine's bias, namely that biases may originate from (i) the programmers' cultural background, such as education or line of work, or (ii) the contextual programming environment, such as software requirements or developer tools. Combining an experimental and comparative design, we studied the effects of cultural metaphors and contextual metaphors, and tested whether each of these would `transfer' from the programmer to program, thus constituting a machine bias. The results show (i) that cultural metaphors influence the programmer's choices and (ii) that `induced' contextual metaphors can be used to moderate or exacerbate the effects of the cultural metaphors. This supports our hypothesis that biases in automated systems do not always originate from within the machine's training data. Instead, machines may also `replicate' and `reproduce' biases from the programmers' cultural background by the transfer of cultural metaphors into the programming process. Implications for academia and professional practice range from the micro programming-level to the macro national-regulations or educational level, and span across all societal domains where software-based systems are operating such as the popular AI-based automated decision support systems.Comment: 40 pages of which 7 pages of Appendix, 26 Figures, 2 Table

Field theory of interacting polaritons under drive and dissipation

This thesis explores systems that exhibit strong coupling between an optical cavity field and a many-particle system. To treat the drive and dissipative nature of the cavity on the same footing as the dynamics of the many-particle system, we use a non-equilibrium field theoretic approach. The first system considered is an ultracold bosonic gas trapped inside a cavity. The dispersive coupling between the cavity field and the atoms' motion leads to the formation of a polariton. We show how a modulation of the pump laser on the energy scale of the transverse cavity mode splitting can be used to create effective interactions between different cavity modes. This effective interaction results in the polariton acquiring a multimode nature, exemplified by avoided crossings in the cavity spectrum. As the laser power is increased, the polariton softens and at a critical power becomes unstable. This instability signals the transition into a superradiant state. If the multimode polariton contains a cavity mode with an effective negative detuning, then the transition does not happen through a mode softening but at a finite frequency. To investigate this, classical non-linear equations are constructed from the action and from these we derive the critical couplings and frequencies. It is shown how the superradiant transition happening at a finite frequency is a consequence of a competition between the negatively and the positively detuned cavity modes making up the polariton. The finite-frequency transition is found to be equivalent to a Hopf bifurcation and leads to the emergence of limit cycles. Our analysis shows that the system can exhibit both bistabilities and evolution constricted to a two-torus. We end the investigation by showing how interactions among the atoms combined with the emerging limit cycle open new phonon scattering channels. The second system considered in the thesis is inspired by the recent experiments on gated Transition-metal dichalcogenides (TMD) monolayers inside cavities. An exciton within the TMD can couple strongly to the cavity and, due to the electronic gating, also interact strongly with the conduction electrons. To treat the strong interactions of the excitons with both cavity and electrons, we solve the coupled equations for the correlation functions non-perturbatively within a ladder approximation. The strong interactions give rise to new quasiparticles known as polaron-polaritons. By driving the system through the cavity, we show how the competition between electron-induced momentum relaxation and cavity loss leads to the accumulation of polaritons at a small but finite momentum, which is accompanied by significant decrease of the polariton linewidth Due to the hybrid nature of the polaron-polariton, we show that this behavior can by qualitatively modified by changing the cavity detuning

Anaerobic digestion as a tool to eliminate animal parasites and weed seeds

Anaerobic digestion of residual materials from animals and crops offers an opportunity to simultaneously produce bioenergy and plant fertilizers at single farms and in farm communities where input substrate materials and resulting digested residues are shared among member farms. A surplus benefit from this praxis may be the suppressing of propagules from harmful biological pest like animal parasites, pathogens, and weed seeds. In the BIOCONCENS project (http://www.icrofs.dk/Sider/Forskning/foejoIII_bioconcens.html) batch experiments were performed, where survival of six species of weeds and the pigs large roundworm Ascaris suum (non-embryonated eggs) was assessed under conditions similar to biogas plants managed at meso- (37°C) and thermophilic (50°C) conditions. Cattle manure was used as digestion substrate and experimental units were sampled destructively during time. Regarding survival of A. suum, the effect of thermophilic conditions was highly significant as no eggs survived more than 3 h of incubation at 50°C. Incubation at 37°C did not affect egg survival during the first 48 h and it took up to 10 days before total elimination was reached. Similarly, at 50°C complete mortality of weed seeds, irrespective of species, was reached after less than two days. At mesophilic conditions, seeds of Avena fatua, Sinapsis arvensis, Solidago Canadensis had completely lost germination ability, while Brassica napus, Fallopia convolvulus and Amzinckia micranta still maintained low levels (~1%) of germination ability after one week. Chenopodium album was the only weed species which survived one week at substantial levels (7%) although after 11 d germination ability was totally lost. In general, anaerobic digestion in biogas plants seems an efficient way (thermophilic more efficient than mesophilic) to treat organic farm wastes in a way that suppresses animal parasites and weeds so that the digestates can be applied without risking the spread of these pests

Diamonds for Security: A Non-Interleaving Operational Semantics for the Applied Pi-Calculus

We introduce a non-interleaving structural operational semantics for the applied ?-calculus and prove that it satisfies the properties expected of a labelled asynchronous transition system (LATS). LATS have well-studied relations with other standard non-interleaving models, such as Mazurkiewicz traces or event structures, and are a natural extension of labelled transition systems where the independence of transitions is made explicit. We build on a considerable body of literature on located semantics for process algebras and adopt a static view on locations to identify the parallel processes that perform a transition. By lifting, in this way, work on CCS and ?-calculus to the applied ?-calculus, we lay down a principled foundation for reusing verification techniques such as partial-order reduction and non-interleaving equivalences in the field of security. The key technical device we develop is the notion of located aliases to refer unambiguously to a specific output originating from a specific process. This light mechanism ensures stability, avoiding disjunctive causality problems that parallel extrusion incurs in similar non-interleaving semantics for the ?-calculus

Are we ready for Taenia solium cysticercosis elimination in sub-Saharan Africa?

The World Health Organization announced in November 2014 at the fourth international meeting on 'the control of neglected zoonotic diseases - from advocacy to action', that intervention tools for eliminating Taenia solium taeniosis/cysticercosis (TSTC) are in place. The aim of this work was to elucidate theoretical outcomes of various control options suggested for TSTC elimination in sub-Saharan Africa (SSA) over a 4-year period. Our current knowledge regarding T. solium epidemiology and control primarily builds on studies from Latin America. A simple transmission model - built on data from Latin America - has been used to predict the effect of various interventions such as mass treatment of humans, vaccination and treatment of pigs, and health education of communities, potentially leading to change in bad practices and reducing transmission risks. Based on simulations of the transmission model, even a 4-year integrated One Health approach fails to eliminate TSTC from a small community and in all simulations, the prevalence of human taeniosis and porcine cysticercosis start to rise as soon as the programmes end. Our current knowledge regarding transmission and burden of TSTC in SSA is scarce and while claiming to be tool ready, the selection of diagnostic and surveillance tools, as well as the algorithms and stepwise approaches for control and elimination of TSTC remain major challenges

Drawing with SAT: four methods and A tool for producing railway infrastructure schematics

Schematic drawings showing railway tracks and equipment are commonly used to visualize railway operations and to communicate system specifications and construction blueprints. Recent advances in on-line collaboration and modeling tools have raised the expectations for quickly making changes to models, resulting in frequent changes to layouts, text, and/or symbols in schematic drawings. Automating the creation of high-quality schematic views from geographical and topological models can help engineers produce and update drawings efficiently. This paper introduces four methods for automatically producing schematic railway drawings with increasing level of quality and control over the result. The final method, implemented in the open-source tool that we have developed, can use any combination of the following optimization criteria, which can have different priorities in different use cases: width and height of the drawing, the diagonal line lengths, and the number of bends. We show how to encode schematic railway drawings as an optimization problem over Boolean and numerical domains, using combinations of unary number encoding, lazy difference constraints, and numerical optimization into an incremental SAT formulation. We compare drawings resulting from each of the four methods, applied to models of real-world engineering projects and existing railway infrastructure. We also show how to add symbols and labels to the track plan, which is important for the usefulness of the final outputs. Since the proposed tool is customizable and efficiently produces high-quality drawings from railML 2.x models, it can be used (as it is or extended) both as an integrated module in an industrial design tool like RailCOMPLETE, or by researchers for visualization purposes.publishedVersio

The Soul Annoyed Robot: A Senior Project Report

Our goal for this senior project was to create a competitive robot designed to com- pete in Roborodentia 2019. Our project started during the Winter 2019 quarter, and ended with the competition on May 18, 2019. During that time, we developed an accurate solenoid shooting mechanism, an elevated conveyor belt to carry poker chips, and a servo arm to scoop in stacks of poker chips. These hardware compo- nents were attached to a circular differential-drive wooden base designed to be easy to control. We also planned out our match strategy and implemented this strategy with software written in C/Wiring to program our Arduino Mega. The competition consisted of 4 other teams, each with very different approaches to the problem. We named our robot Soul Annoyed, due to our solenoid-based shooting mechanism. We competed in a double elimination match bracket, and won every round, claiming first place. However, two matches were very close, and we realized that being the best robot was not just about having a winning strategy, it was perhaps more important that the robot could execute any strategy reliably and efficiently

In cylinder visualization of stratified combustion of E85 and main sources of soot formation

The combustion process and soot formation in spark ignited spray guided stratified combustion of E85 was investigated in a single cylinder optical engine with direct injection of fuel using an outward opening piezo actuated injector. The effect of engine rotation frequency, fuel quantity, injection sequence and ignition timing was studied. Combustion, soot formation and soot oxidation was analyzed using cylinder pressure measurements, images recorded using high speed video cameras, the flame emission spectrum and OH^∗ chemiluminescence and soot incandescence imaging. A maximum injection duration was found to exist for direct ignition of the fuel spray. Engine rotation frequency had little effect on the initial and maximum rate of combustion. The maximum rate of combustion decreased with increasing cycle fuel mass when a single injection was used. The rate of combustion and indicated mean effective pressure increased and the combustion variability decreased when the single injection was split into multiple injections in close succession to deliver the same total fuel mass and the last fuel spray was ignited. Ignition of the first fuel spray resulted in a more pronounced change. The absence of soot incandescence during the initial flame propagation suggested flame propagation in a partially mixed fuel and air mixture with stoichiometric to fuel lean regions. A single fuel injection resulted in piston pool fires due to fuel spray impingement on the piston and was the primary source of soot formation. The pool fires persisted until after conditions favorable to oxidation of the soot had ended. Soot formation in the gas phase occurred while favorable soot oxidation conditions existed and was efficiently oxidized. The magnitude of the piston pool fires was reduced using multiple injections. The reduction is attributed to a reduction of the fuel spray penetration length and a smaller effective injection orifice area, resulting in a shorter total duration of fuel spray impingement on the piston crown. Soot formation occurred primarily in the gas phase when the first of two fuel sprays was ignited and persisted due to the second fuel spray entering an existing flame leading to fuel rich combustion