Cette thèse s’intéresse à l’exploitation de la sémantique de données pour la recherche exploratoire. La recherche exploratoire se réfère à des tâches de recherche qui sont très ouvertes, avec de multiples facettes, et itératives. Les données sémantiques et les données liées en particulier, offrent de nouvelles possibilités pour répondre à des requêtes de recherche et des besoins d’information complexes. Dans ce contexte, le nuage de données ouvertes liées (LOD) joue un rôle important en permettant des traitements de données avancés et des interactions innovantes. Nous détaillons un état de l’art de la recherche exploratoire sur les données liées. Puis nous proposons un algorithme de recherche exploratoire à base de données liées basé sur une recherche associative. A partir d’un algorithme de propagation d’activation nous proposons une nouvelle formule de diffusion optimisée pour les graphes typés. Nous proposons ensuite des formalisations supplémentaires de plusieurs modes d’interrogation avancée. Nous présentons également une architecture logicielle innovante basée sur deux choix de conception paradigmatiques. D’abord, les résultats doivent être calculés à la demande. Deuxièmement, les données sont consommées à distance à partir de services SPARQL distribués. Cela nous permet d’atteindre un niveau élevé de flexibilité en termes d’interrogation et de sélection des données. L’application Discovery Hub implémente ces résultats et les présente dans une interface optimisée pour l’exploration. Nous évaluons notre approche grâce à plusieurs campagnes avec des utilisateurs et nous ouvrons le débat sur de nouvelles façons d’évaluer les moteurs de recherche exploratoires. / The general topic of the thesis is web search. It focused on how to leverage the data semantics for exploratory search. Exploratory search refers to cognitive consuming search tasks that are open-ended, multi-faceted, and iterative like learning or topic investigation. Semantic data and linked data in particular offer new possibilities to solve complex search queries and information needs including exploratory search ones. In this context the linked open data cloud plays an important role by allowing advanced data processing and innovative interactions model elaboration. First, we detail a state-of-the-art review of linked data based exploratory search approaches and systems. Then we propose a linked data based exploratory search solution which is mainly based on an associative retrieval algorithm. We started from a spreading activation algorithm and proposed new diffusion formula optimized for typed graph. Starting from this formalization we proposed additional formalizations of several advanced querying modes in order to solve complex exploratory search needs. We also propose an innovative software architecture based on two paradigmatic design choices. First the results have to be computed at query-time. Second the data are consumed remotely from distant SPARQL endpoints. This allows us to reach a high level of flexibility in terms of querying and data selection. We specified, designed and evaluated the Discovery Hub web application that retrieves the results and present them in an interface optimized for exploration. We evaluate our approach thanks to several human evaluations and we open the discussion about new ways to evaluate exploratory search engines.

This thesis deals about a digitizer design. The digitizer is part of air-band monitoring receiver. Requirement is digitalization of two audio signals. The device communicates with PC through USB interface and it provides reading and writing to SD card. The STM32F4DISCOVERY development board with processor STM32F407VGT6 was used for design and function testing. This development kit is supplemented with other peripherals on an extern board (input audio circuits and SD slots). The thesis describes briefly theory for each issue which this project deals with. One part is engaged to the hardware design. Then there is a description of the PC software for the device controlling. The main part of the thesis is about the development of the firmware for MCU, which manages AD conversion, formatting of the voice signal, USB communication (HID and Mass Storage class), recording and reading from the SD card and additional peripherals.

No description available.

Glaspärlor är en viktig del av vikingatidens dräkt. Syftet med denna studie är att få en inblick i hur befolkningen i Fröjel såg på och använde pärlor. Aktörskap som teori används i studien. Undersökningsmaterialet är 100 glaspärlor som kan dateras mellan 900–1000 e.v.t och har hittats i Fröjel, genom Fröjel Discovery Programme. Pärltyperna sorterades med Callmers typologi och har tillsammans med pärlornas fyndplats analyserats och diskuterats. Undersökningsmaterialet har diskuterats utifrån tidigare forskning kring vikingatiden, handelssystem och glaspärlor, som ett material och föremål. Callmers typologi bidrog till att urskilja pärlornas ursprung vilka stämmer med Fröjels handelsvägar. Studien visar, med hjälp av Callmers typologi och rumslig spridning, att pärlorna är av värde och ett resultat av social struktur, handel och val gjorda av både individen och grupper vilket ökar relevansen av aktörskap vad gäller individers val och kläddetaljer. / Glass beads have long been a part of the viking age costume. The purpose of this study is to get an insight to how the population of Fröjel viewed and used the beads. Agency as a theory was used in the study. The research material is 100 glass beads that can be dated between 900-1000 CE, have been found in Fröjel, through Fröjel Discovery Programme. The bead types have been sorted with Callmers typology and along with the location of the finds have been analyzed and discussed. The research material has been discussed based on previous research surrounding the viking age, trade systems and glass beads as a material and item. The origins of the beads which could be distinguished through Callmers typology matches with Fröjels trade networks. The study shows, with the help of Callmer’s typology and the spatial spread of the beads, that the beads are an accessory of value and a result of social structure, such as trade, and choices made by both the individual and groups which heightens the relevance of agency regarding individuals and clothing details.

Microbial natural products have been a source for new drugs for many decades and are unrivaled in their capacity to generate not only future therapeutic agents, but also providing key agents for agricultural and industrial use. LC-MS/MS based metabolomic tools and technologies have been developed that can rapidly dereplicate nonribosomal peptides and statistically identify related congeners in an automated nontargeted process from complex natural product extracts with nanogram sensitivity. This data-base search approach is designed to handle linear, cyclic and cyclic-branched nonribosomal peptides from proteinogenic and nonproteinogenic amino acids without genomic data or traditional bioactivity directed fractionation. Chemometric work-flows combined with a comprehensive metabolomic guided discovery strategy were used to profile the chemical space of a diverse collection of understudied fungal endophytes from fruiting plants. This approach allowed for the prioritization of unique isolates and for the focused discovery, isolation and characterization of distinct outlier metabolites by LC-SPE, 1D and 2D NMR, HRMS and single crystal X-ray analysis. These metabolomic tools and strategies have led to the discovery and characterization of 35 new and over 40 known natural products, many of which are biologically active. This thesis with enabling metabolomic tools and novel discoveries has demonstrated the utility of these analytical methodologies as an effective strategy for the untargeted discovery of new natural products from bacteria and endophytic fungi. / Thesis / Doctor of Philosophy (PhD)

<p dir="ltr">Learning, planning, and representing knowledge at multiple levels of temporal abstractions provide an agent with the ability to predict consequences of different courses of actions, which is essential for improving the performance of sequential decision making. However, discovering effective temporal abstractions, which the agent can use as skills, and adopting the constructed temporal abstractions for efficient policy learning can be challenging. Despite significant advancements in single-agent settings, temporal abstractions in multi-agent systems remains underexplored. This thesis addresses this research gap by introducing novel algorithms for discovering and employing temporal abstractions in both cooperative and competitive multi-agent environments. We first develop an unsupervised spectral-analysis-based discovery algorithm, aiming at finding temporal abstractions that can enhance the joint exploration of agents in complex, unknown environments for goal-achieving tasks. Subsequently, we propose a variational method that is applicable for a broader range of collaborative multi-agent tasks. This method unifies dynamic grouping and automatic multi-agent temporal abstraction discovery, and can be seamlessly integrated into the commonly-used multi-agent reinforcement learning algorithms. Further, for competitive multi-agent zero-sum games, we develop an algorithm based on Counterfactual Regret Minimization, which enables agents to form and utilize strategic abstractions akin to routine moves in chess during strategy learning, supported by solid theoretical and empirical analyses. Collectively, these contributions not only advance the understanding of multi-agent temporal abstractions but also present practical algorithms for intricate multi-agent challenges, including control, planning, and decision-making in complex scenarios.</p>

The media landscape is changing and Internet-based streaming services for children are becoming increasingly popular. The concept of online streaming extends freedom and control over content selection but discovering new content is often experienced as troublesome. The objective of this thesis is to identify parameters to make it easier for users of streaming services for children to discover and watch unfamiliar programs. Guidelines are formed based on literature studies, interviews, observations, a survey, a benchmark, data analysis with Adobe Analytics, a workshop and finally user tests with prototypes. These guidelines conclude that content should be categorized, dynamicized, highlighted and socially engaging. Categorization based on age is primarily important but interests and genres can also be used to make children more interested in a title. Content should be dynamic, customizable and personal to each user to give more accurate recommendations based on age and interests. Making one alternative more visually prominent will make this alternative more interesting especially for younger children and social features with information about other users opinions can motivate a decision to discover new content among older children.

Master of Science / Department of Agricultural Economics / Ted C. Schroeder / Very rapid growth in the ethanol industry has led to a void of information regarding price dynamics and utilization of distiller's grains. Understanding market conditions is essential for livestock producers to make informed decisions in the procurement of feedstuffs, especially as grain price levels have recently increased substantially. In this study, distiller's grain price discovery dynamics are evaluated to develop an understanding of spatial price relationships. The knowledge of price relationships reveals that users of distiller's grain should shop around when procuring the feedstuff. Additionally, because animal performance may be altered with increased inclusion of distiller's grains, regional competitive advantages could shift fed cattle production to geographic regions characterized by high of ethanol production plants. Therefore, the cost of current grain processing methods are evaluated to enhance the awareness of regional competitiveness and long term sustainability. The combination of these two objectives allows producers to better realize the implications of the ethanol industry on their ability to maintain their operations into the near future.

Doctor of Philosophy / Department of Statistics / Suzanne Dubnicka / DNA barcodes are short strands of nucleotide bases taken from the cytochrome c oxidase subunit 1 (COI) of the mitochondrial DNA (mtDNA). A single barcode may have the form C C G G C A T A G T A G G C A C T G . . . and typically ranges in length from 255 to around 700 nucleotide bases. Unlike nuclear DNA (nDNA), mtDNA remains largely unchanged as it is passed from mother to offspring. It has been proposed that these barcodes may be used as a method of differentiating between biological species (Hebert, Ratnasingham, and deWaard 2003). While this proposal is sharply debated among some taxonomists (Will and Rubinoff 2004), it has gained momentum and attention from biologists. One issue at the heart of the controversy is the use of genetic distance measures as a tool for species differentiation. Current methods of species classification utilize these distance measures that are heavily dependent on both evolutionary model assumptions as well as a clearly defined "gap" between intra- and interspecies variation (Meyer and Paulay 2005). We point out the limitations of such distance measures and propose a character-based method of species classification which utilizes an application of Bayes' rule to overcome these deficiencies. The proposed method is shown to provide accurate species-level classification. The proposed methods also provide answers to important questions not addressable with current methods.

The prospect of replacing existing fixed networks with cheap, flexible and evenmobile low-power wireless network has been a strong research driver in recent years.However, many challenges still exist: reliability is hampered by unstable and burstycommunication links; the wireless medium is getting congested by an increasingnumber of wireless devices; and life-times are limited due to difficulties in developingefficient duty-cycling mechanisms. These challenges inhibit the industry to fullyembrace and exploit the capabilities and business opportunities that low-powerwireless devices offer. In this thesis, we propose, design, implement, and evaluateprotocols and systems to increase flexibility and improve efficiency of low-powerwireless communications. First, we present MobiSense, a system architecture for energy-efficient communicationsin micro-mobility sensing scenarios. MobiSense is a hybrid architecturecombining a fixed infrastructure network and mobile sensor nodes. Simulations andexperimental results show that the system provides high throughput and reliabilitywith low-latency handoffs. Secondly, we investigate if and how multi-channel communication can mitigate theimpact of link dynamics on low-power wireless protocols. Our study is motivated bya curiosity to reconcile two opposing views: that link dynamics is best compensatedby either (i) adaptive routing, or (ii) multi-channel communication. We perform acomprehensive measurement campaign and evaluate performance both in the singlelink and over a multi-hop network. We study packet reception ratios, maximumburst losses, temporal correlation of losses and loss correlations across channels.The evaluation shows that multi-channel communication significantly reduces linkburstiness and packet losses. In multi-hop networks, multi-channel communicationsand adaptive routing achieves similar end-to-end reliability in dense topologies,while multi-channel communication outperforms adaptive routing in sparse networkswhere re-routing options are limited. Third, we address the problem of distributed information exchange in proximitybasednetworks. First, we consider randomized information exchange and assess thepotential of multi-channel epidemic discovery. We propose an epidemic neightbordiscoverymechanism that reduces discovery times considerably compared to singlechannelprotocols in large and dense networks. Then, the idea is extended todeterministic information exchange. We propose, design and evaluate an epidemicinformation dissemination mechanism with strong performance both in theory andpractice. Finally, we apply some of the concepts from epidemic discovery to the designof an asynchronous, sender-initiated multi-channel medium access protocol. Theprotocol combines a novel mechanism for rapid schedule learning that avoids perpacketchannel negotiations with the use of burst data transfer to provide efficientsupport of ’multiple contending unicast and parallel data flows. / De senaste åren har forskning inom trådlös kommunikation drivits av önskemåletom att kunna ersätta nuvarande trådbundna kommunikationslänkar med trådlösa lågenergialternativ.Dock kvarstår många utmaningar, såsom instabila och sporadiskalänkar, överbelastning på grund av en ökning i antal trådlösa enheter, hur maneffektivt kan växla duty-cycling mekanismen för att förlänga nätverkens livstid,med flera. Dessa utmaningar begränsar industrin från att ta till sig och utnyttjade fördelar som trådlösa lågenergialternativ kan medföra. I den här avhandlingenföreslår, designar, implementerar och utvärderar vi protokoll och system som kanförbättra de nuvarande trådlösa lågenergialternativen. Först presenterar vi MobiSense, en systemarkitektur för energibesparande kommunikationi mikro-mobila sensorscenarier. MobiSense är en hybridarkitektur somkombinerar ett fast infrastrukturnätverk med rörliga sensornoder. Simulerings- ochexperimentella resultat visar att systemet uppnår en högre överföringskapacitet ochtillförlitlighet samtidigt som överlämnandet mellan basstationer har låg latens. I den andra delen behandlar vi hur effekterna från länkdynamiken hos protokollför lågenergikommunikation kan minskas, och försöker förena idéerna hos två motståendesynsätt: (i) flerkanalskommunikation och (ii) adaptiv routing. Vi analyserarenkanals- och flerkanalskommunikation över en-stegslänkar i termer av andelenmottagna paket kontra andelen förlorade, den maximala sporadiska förlusten avpaket, tidskorrelation för förluster och förlustkorrelation mellan olika kanaler. Resultatenindikerar att flerkanalskommunikation med kanalhoppning kraftigt minskardet sporadiska uppträdandet hos länkarna och korrelationen mellan paketförluster.För flerstegsnätverk uppvisar flerkanalskommunikation och adaptiv routingliknande tillförlitlighet i täta topologier, medan flerkanalskommunikation har bättreprestanda än adaptiv routing i glesa nätverk med sporadiska länkar. I den tredje delen studeras distribuerat informationsutbyte i närhetsbaseradenätverk. Först betraktas det slumpmässiga fallet och vi fastställer potentialen hosflerkanalig indirekt utforskning av nätverket. Vi analyserar ett trestegs protokoll,som möjliggör en snabbare utforskning av nätverket. Sedan föreslår vi en ny algoritmför att upptäcka grannarna i ett flerkanalsnätverk, som kraftigt minskarutforskningstiden i jämförelse med ett enkanalsprotokoll. Vi utökar även problemettill det deterministiska fallet och föreslår en mekanism för informationsspridningsom påskyndar utforskningstiderna för deterministiska protokoll. Utvidgningen hartvå huvudförbättringar som leder till kraftigt ökad prestanda samtidigt som degaranterar att utforskningsprocessen är deterministisk. Till sist applicerar vi koncepten rörande indirekt utforskning för att designa,implementera och evaluera ett asynkront sändare-initierat flerkanals MAC protokollför trådlös lågenergikommunikation. Protokollet kombinerar en ny mekanism försnabbt lärande av tidsschemat, vilket undviker kanalförhandling för varje paket,med sporadisk dataöverföring. Detta möjliggör ett effektivt tillhandahållande avflera konkurrerande och parallella dataflöden. / <p>QC 20151204</p>