Context-based services for mobile devices

The subject of this master’s thesis was developing a context-based reminder service for mobile devices. Possible sources of context were identified and analyzed. One such source is geographical location obtained via a GPS receiver. These receivers consume a lot of power and techniques and algorithms for reducing power consumptions were proposed and analyzed. The service was implemented as an application on a series 60 mobile phone. The application requirements, user interface and architecture are presented. The end-user experiences are discussed and possible future development and research areas are presented.

Application of Neural Network Methods in the Prediction of Stock Markets

The purpose of the research is to define practical profit which can be achieved using neural network methods as a prediction instrument. The thesis investigates the ability of neural networks to forecast future events. This capability is checked on the example of price prediction during intraday trading on stock market. The executed experiments show predictions of average 1, 2, 5 and 10 minutes’ prices based on data of one day and made by two different types of forecasting systems. These systems are based on the recurrent neural networks and back propagation neural nets. The precision of the predictions is controlled by the absolute error and the error of market direction. The economical effectiveness is estimated by a special trading system. In conclusion, the best structures of neural nets are tested with data of 31 days’ interval. The best results of the average percent of profit from one transaction (buying + selling) are 0.06668654, 0.188299453, 0.349854787 and 0.453178626, they were achieved for prediction periods 1, 2, 5 and 10 minutes. The investigation can be interesting for the investors who have access to a fast information channel with a possibility of every-minute data refreshment.

Allelic diversity and population structure in Vibrio cholerae O139 Bengal based on nucleotide sequence analysis

Comparative analysis of gene fragments of six housekeeping loci, distributed around the two chromosomes of Vibrio cholerae, has been carried out for a collection of 29 V. cholerae O139 Bengal strains isolated from India during the first epidemic period (1992 to 1993). A toxigenic O1 ElTor strain from the seventh pandemic and an environmental non-O1/non-O139 strain were also included in this study. All loci studied were polymorphic, with a small number of polymorphic sites in the sequenced fragments. The genetic diversity determined for our O139 population is concordant with a previous multilocus enzyme electrophoresis study in which we analyzed the same V. cholerae O139 strains. In both studies we have found a higher genetic diversity than reported previously in other molecular studies. The results of the present work showed that O139 strains clustered in several lineages of the dendrogram generated from the matrix of allelic mismatches between the different genotypes, a finding which does not support the hypothesis previously reported that the O139 serogroup is a unique clone. The statistical analysis performed in the V. cholerae O139 isolates suggested a clonal population structure. Moreover, the application of the Sawyer's test and split decomposition to detect intragenic recombination in the sequenced gene fragments did not indicate the existence of recombination in our O139 population.

A radiochemical method for carbamoyl-phosphate synthetase I: application to rats fed a hyperproteic diet

A method for the measurement of carbamoyl-phosphate synthetase I activity in animal tissues has been developed using the livers of rats under normal and hyperproteic diets. The method is based on the incorporation of 14C-ammonium bicarbonate to carbamoyl-phosphate in the presence of ATP-Mg and N-acetyl-glutamate. The reaction is stopped by chilling, lowering the pH and adding ethanol. Excess bicarbonate is flushed out under a gentle stream of cold CO2. The only label remaining in the medium was that incorporated into carbamoyl-phosphate, since all 14C-CO2 from bicarbonate was eliminated. The method is rapid and requires only a low pressure supply of CO2 to remove the excess substrate. The reaction is linear up to 10 min using homogenate dilutions of 1:20 to 1:200 (w/v). Rat liver activity was in the range of 89±8 nkat/g. Hyperproteic diet resulted in a significant 1.4-fold increase. The design of the method allows for the processing of multiple samples at the same time, and incubation medium manipulation is unnecessary, since the plastic incubation vial and its contents are finally counted together.

Architecture for a Session Initiation Protocol Based Presence Client

Mitä on läsnäolo? Tämä työ määrittelee läsnäolon tietyn henkilön, laitteen tai palvelun halukkuudeksi kommunikoida. Nykyään on olemassa lukuisia läsnäolotietoa levittäviä sovelluksia, joista jokainen käyttää erilaista protokollaa tehtävän suorittamiseen. Vasta viime aikoina sovellusten kehittäjät ovat huomanneet tarpeen yhdelle sovellukselle, joka kykenee tukemaan lukuisia läsnäoloprotokollia. Session Initiation Protocol (SIP) voi levittää läsnäolotietoa muiden ominaisuuksiensa lisäksi. Kun muita protokollia käytetään vain reaaliaikaiseen viestintään ja läsnäolotiedon lähetykseen, SIP pystyy moniin muihinkin asioihin. Se on alunperin suunniteltu aloittamaan, muuttamaan ja lopettamaan osapuolien välisiä multimediaistuntoja. Arkkitehtuurin toteutus käyttää kahta Symbian –käyttöjärjestelmän perusominaisuutta: asiakas-palvelin rakennetta ja kontaktitietokantaa. Asiakaspalvelin rakenne erottaa asiakkaan protokollasta tarjoten perustan laajennettavalle usean protokollan arkkitehtuurille ja kontaktitietokanta toimii läsnäolotietojen varastona. Työn tuloksena on Symbianin käyttöjärjestelmässä toimiva läsnäoloasiakas.

Delivery system for location based information in wireless IP networks

Tämä työ esittelee uuden tarjota paikasta riippuvaa tietoa langattomien tietoverkkojen käyttäjille. Tieto välitetään jokaiselle käyttäjälle tietämättä mitään käyttäjän henkilöllisyydestä. Sovellustason protokollaksi valittiin HTTP, joka mahdollistaa tämän järjestelmän saattaa tietoa perille useimmille käyttäjille, jotka käyttävät hyvinkin erilaisia päätelaitteita. Tämä järjestelmä toimii sieppaavan www-liikenteen välityspalvelimen jatkeena. Erilaisten tietokantojen sisällä on perusteella järjestelmä päättää välitetäänkö tietoa vai ei. Järjestelmä sisältää myös yksinkertaisen ohjelmiston käyttäjien paikantamiseksi yksittäisen tukiaseman tarkkuudella. Vaikka esitetty ratkaisu tähtääkin paikkaan perustuvien mainosten tarjoamiseen, se on helposti muunnettavissa minkä tahansa tyyppisen tiedon välittämiseen käyttäjille.

Comparison of application frameworks designed to support application extensibility

Reusability has become more popular factor in modern software engineering. This is mainly because object-orientation has brought methods that allow reusing more easily. Today more and more application developer thinks how they can reuse already existing applications in their work. If the developer wants to use existing components outside the current project, he can use design patterns, class libraries or frameworks. These provide solution for specific or general problems that has been already encountered. Application frameworks are collection of classes that provides base for the developer. Application frameworks are mostly implementation phase tools, but can also be used in application design. The main purpose of the frameworks is separate domain specific functionalities from the application specific. Usually the frameworks are divided into two categories: black and white box. Difference between those categories is the way the reuse is done. The application frameworks provide properties that can be examined and compared between different frameworks. These properties are: extensibility, reusability, modularity and scalability. These examine how framework will handle different platforms, changes in framework, increasing demand for resources, etc. Generally application frameworks do have these properties in good level. When comparing general purpose framework and more specific purpose framework, the main difference can be located in reusability of frameworks. It is mainly because the framework designed to specific domain can have constraints from external systems and resources. With general purpose framework these are set by the application developed based on the framework.

Immunity and inflammation in status epilepticus and its sequelae: possibilities for therapeutic application.

Status epilepticus (SE) is a life-threatening neurological emergency often refractory to available treatment options. It is a very heterogeneous condition in terms of clinical presentation and causes, which besides genetic, vascular and other structural causes also include CNS or severe systemic infections, sudden withdrawal from benzodiazepines or anticonvulsants and rare autoimmune etiologies. Treatment of SE is essentially based on expert opinions and antiepileptic drug treatment per se seems to have no major impact on prognosis. There is, therefore, urgent need of novel therapies that rely upon a better understanding of the basic mechanisms underlying this clinical condition. Accumulating evidence in animal models highlights that inflammation ensuing in the brain during SE may play a determinant role in ongoing seizures and their long-term detrimental consequences, independent of an infection or auto-immune cause; this evidence encourages reconsideration of the treatment flow in SE patients.

Internet-Based Brief Intervention to Prevent Unhealthy Alcohol Use among Young Men: A Randomized Controlled Trial.

Alcohol use is one of the leading modifiable morbidity and mortality risk factors among young adults. 2 parallel-group randomized controlled trial with follow-up at 1 and 6 months. Internet based study in a general population sample of young men with low-risk drinking, recruited between June 2012 and February 2013. Intervention: Internet-based brief alcohol primary prevention intervention (IBI). The IBI aims at preventing an increase in alcohol use: it consists of normative feedback, feedback on consequences, calorific value alcohol, computed blood alcohol concentration, indication that the reported alcohol use is associated with no or limited risks for health. Intervention group participants received the IBI. Control group (CG) participants completed only an assessment. Alcohol use (number of drinks per week), binge drinking prevalence. Analyses were conducted in 2014-2015. Of 4365 men invited to participate, 1633 did so; 896 reported low-risk drinking and were randomized (IBI: n = 451; CG: n = 445). At baseline, 1 and 6 months, the mean (SD) number of drinks/week was 2.4(2.2), 2.3(2.6), 2.5(3.0) for IBI, and 2.4(2.3), 2.8(3.7), 2.7(3.9) for CG. Binge drinking, absent at baseline, was reported by 14.4% (IBI) and 19.0% (CG) at 1 month and by 13.3% (IBI) and 13.0% (CG) at 6 months. At 1 month, beneficial intervention effects were observed on the number of drinks/week (p = 0.05). No significant differences were observed at 6 months. We found protective short term effects of a primary prevention IBI. Controlled-Trials.com ISRCTN55991918.

Implementing Role Based Access Control into the Enterprise Environment to Support Business and IT Functions

The thesis studies role based access control and its suitability in the enterprise environment. The aim is to research how extensively role based access control can be implemented in the case organization and how it support organization’s business and IT functions. This study points out the enterprise’s needs for access control, factors of access control in the enterprise environment and requirements for implementation and the benefits and challenges it brings along. To find the scope how extensively role based access control can be implemented into the case organization, firstly is examined the actual state of access control. Secondly is defined a rudimentary desired state (how things should be) and thirdly completed it by using the results of the implementation of role based access control application. The study results the role model for case organization unit, and the building blocks and the framework for the organization wide implementation. Ultimate value for organization is delivered by facilitating the normal operations of the organization whilst protecting its information assets.

Análisis de una experiencia de aprendizaje basado en proyectos en la asignatura de Fundamentos de Física = Project based learning: analysis of an experience in Introductory Physics courses

In this work we present and analyze the application of an experience of Project Based Learning (PBL) in the matter of Physics II of the Industrial Design university degree (Girona University) during 2005-2006 courses. This methodology was applied to the Electrostatic and Direct Current subjects. Furthermore, evaluation and self evaluation results were shown and the academic results were compared with results obtained in the same subjects applying conventional teaching methods

Prototype of a web-based participative decision support platform in natural hazards and risk management

This paper presents the current state and development of a prototype web-GIS (Geographic Information System) decision support platform intended for application in natural hazards and risk management, mainly for floods and landslides. This web platform uses open-source geospatial software and technologies, particularly the Boundless (formerly OpenGeo) framework and its client side software development kit (SDK). The main purpose of the platform is to assist the experts and stakeholders in the decision-making process for evaluation and selection of different risk management strategies through an interactive participation approach, integrating web-GIS interface with decision support tool based on a compromise programming approach. The access rights and functionality of the platform are varied depending on the roles and responsibilities of stakeholders in managing the risk. The application of the prototype platform is demonstrated based on an example case study site: Malborghetto Valbruna municipality of North-Eastern Italy where flash floods and landslides are frequent with major events having occurred in 2003. The preliminary feedback collected from the stakeholders in the region is discussed to understand the perspectives of stakeholders on the proposed prototype platform.

Home Blood Pressure Measurement – Epidemiology and Clinical Application

Verenpaineen kotimittaus − epidemiologia ja kliininen käyttö Kohonnutta verenpainetta, maailmanlaajuisesti merkittävintä ennenaikaiselle kuolemalle altistavaa riskitekijää, ei voida tunnistaa tai hoitaa ilman tarkkoja ja käytännöllisiä verenpaineen mittausmenetelmiä. Verenpaineen kotimittaus on saavuttanut suuren suosion potilaiden keskuudessa. Lääkärit eivät ole kuitenkaan vielä täysin hyväksyneet verenpaineen kotimittausta, sillä riittävä todistusaineisto sen toimivuudesta ja eduista on puuttunut. Tämän tutkimuksen tarkoituksena oli osoittaa, että kotona mitattu verenpaine (kotipaine) on perinteistä vastaanotolla mitattua verenpainetta (vastaanottopaine) tarkempi, ja että se on tehokas myös kliinisessä käytössä. Tutkimme kotipaineen käyttöä verenpainetaudin diagnosoinnissa ja hoidossa. Lisäksi tarkastelimme kotipaineen yhteyttä verenpainetaudin aiheuttamiin kohde-elinvaurioihin. Ensimmäinen aineisto, joka oli edustava otos Suomen aikuisväestöstä, koostui 2 120 45–74-vuotiaasta tutkimushenkilöstä. Tutkittavat mittasivat kotipainettaan viikon ajan ja osallistuivat terveystarkastukseen, johon sisältyi kliinisen tutkimuksen ja haastattelun lisäksi sydänfilmin otto ja vastaanottopaineen mittaus. 758 tutkittavalle suoritettiin lisäksi kaulavaltimon seinämän intima-mediakerroksen paksuuden (valtimonkovettumataudin mittari) mittaus ja 237:lle valtimon pulssiaallon nopeuden (valtimojäykkyyden mittari) mittaus. Toisessa aineistossa, joka koostui 98 verenpainetautia sairastavasta potilaasta, hoitoa ohjattiin satunnaistamisesta riippuen joko ambulatorisen eli vuorokausirekisteröinnillä mitatun verenpaineen tai kotipaineen perusteella. Vastaanottopaine oli kotipainetta merkittävästi korkeampi (systolisen/diastolisen paineen keskiarvoero oli 8/3 mmHg) ja yksimielisyys verenpainetaudin diagnoosissa kahden menetelmän välillä oli korkeintaan kohtalainen (75 %). 593 tutkittavasta, joilla oli kohonnut verenpaine vastaanotolla, 38 %:lla oli normaali verenpaine kotona eli ns. valkotakkiverenpaine. Verenpainetauti voidaan siis ylidiagnosoida joka kolmannella potilaalla seulontatilanteessa. Valkotakkiverenpaine oli yhteydessä lievästi kohonneeseen verenpaineeseen, matalaan painoindeksiin ja tupakoimattomuuteen, muttei psykiatriseen sairastavuuteen. Valkotakkiverenpaine ei kuitenkaan vaikuttaisi olevan täysin vaaraton ilmiö ja voi ennustaa tulevaa verenpainetautia, sillä siitä kärsivien sydän- ja verisuonitautien riskitekijäprofiili oli normaalipaineisten ja todellisten verenpainetautisten riskitekijäprofiilien välissä. Kotipaineella oli vastaanottopainetta vahvempi yhteys verenpainetaudin aiheuttamiin kohde-elinvaurioihin (intima-mediakerroksen paksuus, pulssiaallon nopeus ja sydänfilmistä todettu vasemman kammion suureneminen). Kotipaine oli tehokas verenpainetaudin hoidon ohjaaja, sillä kotipaineeseen ja ambulatoriseen paineeseen, jota on pidetty verenpainemittauksen ”kultaisena standardina”, perustuva lääkehoidon ohjaus johti yhtä hyvään verenpaineen hallintaan. Tämän ja aikaisempien tutkimusten tulosten pohjalta voidaan todeta, että verenpaineen kotimittaus on selkeä parannus perinteiseen vastaanotolla tapahtuvaan verenpainemittaukseen verrattuna. Verenpaineen kotimittaus on käytännöllinen, tarkka ja laajasti saatavilla oleva menetelmä, josta voi tulla jopa ensisijainen vaihtoehto verenpainetautia diagnosoitaessa ja hoitaessa. Verenpaineen mittauskäytäntöön tarvitaan muutos, sillä näyttöön perustuvan lääketieteen perusteella vaikuttaa, että vastaanotolla tapahtuvaa verenpainemittausta tulisi käyttää vain seulontatarkoitukseen.

Development of a systematic computer vision-based method to analyse and compare images of false identity documents for forensic intelligence purposes-Part I: acquisition, calibration and validation issues

Following their detection and seizure by police and border guard authorities, false identity and travel documents are usually scanned, producing digital images. This research investigates the potential of these images to classify false identity documents, highlight links between documents produced by a same modus operandi or same source, and thus support forensic intelligence efforts. Inspired by previous research work about digital images of Ecstasy tablets, a systematic and complete method has been developed to acquire, collect, process and compare images of false identity documents. This first part of the article highlights the critical steps of the method and the development of a prototype that processes regions of interest extracted from images. Acquisition conditions have been fine-tuned in order to optimise reproducibility and comparability of images. Different filters and comparison metrics have been evaluated and the performance of the method has been assessed using two calibration and validation sets of documents, made up of 101 Italian driving licenses and 96 Portuguese passports seized in Switzerland, among which some were known to come from common sources. Results indicate that the use of Hue and Edge filters or their combination to extract profiles from images, and then the comparison of profiles with a Canberra distance-based metric provides the most accurate classification of documents. The method appears also to be quick, efficient and inexpensive. It can be easily operated from remote locations and shared amongst different organisations, which makes it very convenient for future operational applications. The method could serve as a first fast triage method that may help target more resource-intensive profiling methods (based on a visual, physical or chemical examination of documents for instance). Its contribution to forensic intelligence and its application to several sets of false identity documents seized by police and border guards will be developed in a forthcoming article (part II).

Assessing the added value of wastewater-based epidemiology to monitor illicit drug use

Wastewater-based epidemiology consists in acquiring relevant information about the lifestyle and health status of the population through the analysis of wastewater samples collected at the influent of a wastewater treatment plant. Whilst being a very young discipline, it has experienced an astonishing development since its firs application in 2005. The possibility to gather community-wide information about drug use has been among the major field of application. The wide resonance of the first results sparked the interest of scientists from various disciplines. Since then, research has broadened in innumerable directions. Although being praised as a revolutionary approach, there was a need to critically assess its added value, with regard to the existing indicators used to monitor illicit drug use. The main, and explicit, objective of this research was to evaluate the added value of wastewater-based epidemiology with regards to two particular, although interconnected, dimensions of illicit drug use. The first is related to trying to understand the added value of the discipline from an epidemiological, or societal, perspective. In other terms, to evaluate if and how it completes our current vision about the extent of illicit drug use at the population level, and if it can guide the planning of future prevention measures and drug policies. The second dimension is the criminal one, with a particular focus on the networks which develop around the large demand in illicit drugs. The goal here was to assess if wastewater-based epidemiology, combined to indicators stemming from the epidemiological dimension, could provide additional clues about the structure of drug distribution networks and the size of their market. This research had also an implicit objective, which focused on initiating the path of wastewater- based epidemiology at the Ecole des Sciences Criminelles of the University of Lausanne. This consisted in gathering the necessary knowledge about the collection, preparation, and analysis of wastewater samples and, most importantly, to understand how to interpret the acquired data and produce useful information. In the first phase of this research, it was possible to determine that ammonium loads, measured directly in the wastewater stream, could be used to monitor the dynamics of the population served by the wastewater treatment plant. Furthermore, it was shown that on the long term, the population did not have a substantial impact on consumption patterns measured through wastewater analysis. Focussing on methadone, for which precise prescription data was available, it was possible to show that reliable consumption estimates could be obtained via wastewater analysis. This allowed to validate the selected sampling strategy, which was then used to monitor the consumption of heroin, through the measurement of morphine. The latter, in combination to prescription and sales data, provided estimates of heroin consumption in line with other indicators. These results, combined to epidemiological data, highlighted the good correspondence between measurements and expectations and, furthermore, suggested that the dark figure of heroin users evading harm-reduction programs, which would thus not be measured by conventional indicators, is likely limited. In the third part, which consisted in a collaborative study aiming at extensively investigating geographical differences in drug use, wastewater analysis was shown to be a useful complement to existing indicators. In particular for stigmatised drugs, such as cocaine and heroin, it allowed to decipher the complex picture derived from surveys and crime statistics. Globally, it provided relevant information to better understand the drug market, both from an epidemiological and repressive perspective. The fourth part focused on cannabis and on the potential of combining wastewater and survey data to overcome some of their respective limitations. Using a hierarchical inference model, it was possible to refine current estimates of cannabis prevalence in the metropolitan area of Lausanne. Wastewater results suggested that the actual prevalence is substantially higher compared to existing figures, thus supporting the common belief that surveys tend to underestimate cannabis use. Whilst being affected by several biases, the information collected through surveys allowed to overcome some of the limitations linked to the analysis of cannabis markers in wastewater (i.e., stability and limited excretion data). These findings highlighted the importance and utility of combining wastewater-based epidemiology to existing indicators about drug use. Similarly, the fifth part of the research was centred on assessing the potential uses of wastewater-based epidemiology from a law enforcement perspective. Through three concrete examples, it was shown that results from wastewater analysis can be used to produce highly relevant intelligence, allowing drug enforcement to assess the structure and operations of drug distribution networks and, ultimately, guide their decisions at the tactical and/or operational level. Finally, the potential to implement wastewater-based epidemiology to monitor the use of harmful, prohibited and counterfeit pharmaceuticals was illustrated through the analysis of sibutramine, and its urinary metabolite, in wastewater samples. The results of this research have highlighted that wastewater-based epidemiology is a useful and powerful approach with numerous scopes. Faced with the complexity of measuring a hidden phenomenon like illicit drug use, it is a major addition to the panoply of existing indicators. -- L'épidémiologie basée sur l'analyse des eaux usées (ou, selon sa définition anglaise, « wastewater-based epidemiology ») consiste en l'acquisition d'informations portant sur le mode de vie et l'état de santé d'une population via l'analyse d'échantillons d'eaux usées récoltés à l'entrée des stations d'épuration. Bien qu'il s'agisse d'une discipline récente, elle a vécu des développements importants depuis sa première mise en oeuvre en 2005, notamment dans le domaine de l'analyse des résidus de stupéfiants. Suite aux retombées médiatiques des premiers résultats de ces analyses de métabolites dans les eaux usées, de nombreux scientifiques provenant de différentes disciplines ont rejoint les rangs de cette nouvelle discipline en développant plusieurs axes de recherche distincts. Bien que reconnu pour son coté objectif et révolutionnaire, il était nécessaire d'évaluer sa valeur ajoutée en regard des indicateurs couramment utilisés pour mesurer la consommation de stupéfiants. En se focalisant sur deux dimensions spécifiques de la consommation de stupéfiants, l'objectif principal de cette recherche était focalisé sur l'évaluation de la valeur ajoutée de l'épidémiologie basée sur l'analyse des eaux usées. La première dimension abordée était celle épidémiologique ou sociétale. En d'autres termes, il s'agissait de comprendre si et comment l'analyse des eaux usées permettait de compléter la vision actuelle sur la problématique, ainsi que déterminer son utilité dans la planification des mesures préventives et des politiques en matière de stupéfiants actuelles et futures. La seconde dimension abordée était celle criminelle, en particulier, l'étude des réseaux qui se développent autour du trafic de produits stupéfiants. L'objectif était de déterminer si cette nouvelle approche combinée aux indicateurs conventionnels, fournissait de nouveaux indices quant à la structure et l'organisation des réseaux de distribution ainsi que sur les dimensions du marché. Cette recherche avait aussi un objectif implicite, développer et d'évaluer la mise en place de l'épidémiologie basée sur l'analyse des eaux usées. En particulier, il s'agissait d'acquérir les connaissances nécessaires quant à la manière de collecter, traiter et analyser des échantillons d'eaux usées, mais surtout, de comprendre comment interpréter les données afin d'en extraire les informations les plus pertinentes. Dans la première phase de cette recherche, il y pu être mis en évidence que les charges en ammonium, mesurées directement dans les eaux usées permettait de suivre la dynamique des mouvements de la population contributrice aux eaux usées de la station d'épuration de la zone étudiée. De plus, il a pu être démontré que, sur le long terme, les mouvements de la population n'avaient pas d'influence substantielle sur le pattern de consommation mesuré dans les eaux usées. En se focalisant sur la méthadone, une substance pour laquelle des données précises sur le nombre de prescriptions étaient disponibles, il a pu être démontré que des estimations exactes sur la consommation pouvaient être tirées de l'analyse des eaux usées. Ceci a permis de valider la stratégie d'échantillonnage adoptée, qui, par le bais de la morphine, a ensuite été utilisée pour suivre la consommation d'héroïne. Combinée aux données de vente et de prescription, l'analyse de la morphine a permis d'obtenir des estimations sur la consommation d'héroïne en accord avec des indicateurs conventionnels. Ces résultats, combinés aux données épidémiologiques ont permis de montrer une bonne adéquation entre les projections des deux approches et ainsi démontrer que le chiffre noir des consommateurs qui échappent aux mesures de réduction de risque, et qui ne seraient donc pas mesurés par ces indicateurs, est vraisemblablement limité. La troisième partie du travail a été réalisée dans le cadre d'une étude collaborative qui avait pour but d'investiguer la valeur ajoutée de l'analyse des eaux usées à mettre en évidence des différences géographiques dans la consommation de stupéfiants. En particulier pour des substances stigmatisées, telles la cocaïne et l'héroïne, l'approche a permis d'objectiver et de préciser la vision obtenue avec les indicateurs traditionnels du type sondages ou les statistiques policières. Globalement, l'analyse des eaux usées s'est montrée être un outil très utile pour mieux comprendre le marché des stupéfiants, à la fois sous l'angle épidémiologique et répressif. La quatrième partie du travail était focalisée sur la problématique du cannabis ainsi que sur le potentiel de combiner l'analyse des eaux usées aux données de sondage afin de surmonter, en partie, leurs limitations. En utilisant un modèle d'inférence hiérarchique, il a été possible d'affiner les actuelles estimations sur la prévalence de l'utilisation de cannabis dans la zone métropolitaine de la ville de Lausanne. Les résultats ont démontré que celle-ci est plus haute que ce que l'on s'attendait, confirmant ainsi l'hypothèse que les sondages ont tendance à sous-estimer la consommation de cannabis. Bien que biaisés, les données récoltées par les sondages ont permis de surmonter certaines des limitations liées à l'analyse des marqueurs du cannabis dans les eaux usées (i.e., stabilité et manque de données sur l'excrétion). Ces résultats mettent en évidence l'importance et l'utilité de combiner les résultats de l'analyse des eaux usées aux indicateurs existants. De la même façon, la cinquième partie du travail était centrée sur l'apport de l'analyse des eaux usées du point de vue de la police. Au travers de trois exemples, l'utilisation de l'indicateur pour produire du renseignement concernant la structure et les activités des réseaux de distribution de stupéfiants, ainsi que pour guider les choix stratégiques et opérationnels de la police, a été mise en évidence. Dans la dernière partie, la possibilité d'utiliser cette approche pour suivre la consommation de produits pharmaceutiques dangereux, interdits ou contrefaits, a été démontrée par l'analyse dans les eaux usées de la sibutramine et ses métabolites. Les résultats de cette recherche ont mis en évidence que l'épidémiologie par l'analyse des eaux usées est une approche pertinente et puissante, ayant de nombreux domaines d'application. Face à la complexité de mesurer un phénomène caché comme la consommation de stupéfiants, la valeur ajoutée de cette approche a ainsi pu être démontrée.