Scalable BGP Prefix Selection for Effective Inter-domain Traffic Engineering

Inter-domain Traffic Engineering for multi-homed networks faces a scalability challenge, as the size of BGP routing table continue to grow. In this context, the choice of the best path must be made potentially for each destination prefix, requiring all available paths to be characterised (e.g., through measurements) and compared with each other. Fortunately, it is well-known that a few number of prefixes carry the larger part of the traffic. As a natural consequence, to engineer large volume of traffic only few prefixes need to be managed. Yet, traffic characteristics of a given prefix can greatly vary over time, and little is known on the dynamism of traffic at this aggregation level, including predicting the set of the most significant prefixes in the near future. %based on past observations. Sophisticated prediction methods won't scale in such context. In this paper, we study the relationship between prefix volume, stability, and predictability, based on recent traffic traces from nine different networks. Three simple and resource-efficient methods to select the prefixes associated with the most important foreseeable traffic volume are then proposed. Such proposed methods allow to select sets of prefixes with both excellent representativeness (volume coverage) and stability in time, for which the best routes are identified. The analysis carried out confirm the potential benefits of a route decision engine

Esophageal perforation: diagnostic work-up and clinical decision-making in the first 24 hours

Esophageal perforation is a rare and potentially life-threatening condition. Early clinical suspicion and imaging is important for case management to achieve a good outcome. However, recent studies continue to report high morbidity and mortality greater than 20% from esophageal perforation. At least half of the perforations are iatrogenic, mostly related to endoscopic instrumentation used in the upper gastrointestinal tract, while about a third are spontaneous perforations. Surgical treatment remains an important option for many patients, but a non-operative approach, with or without use of an endoscopic stent or placement of internal or external drains, should be considered when the clinical situation allows for a less invasive approach. The rarity of this emergency makes it difficult for a physician to obtain extensive individual clinical experience; it is also challenging to obtain firm scientific evidence that informs patient management and clinical decision-making. Improved attention to non-specific symptoms and signs and early diagnosis based on imaging may translate into better outcomes for this group of patients, many of whom are elderly with significant comorbidity

Molecular Orbital Theory for Octahedral and Tetrahedral Metal Complexes

Self-consistent charge and configuration (SCCC) molecular orbital calculations are reported for 32 selected octahedral and tetrahedral first-row transition-metal complexes containing halide and chalcogenide ligands. It is found that for the range of metal oxidation states II through IV, Fsigma, chosen to fit the experimental Delta, is a function of only the metal atomic number for constant Fpi. In the range of formal metal oxidation numbers V through VII, Fsigma is also a function of oxidation number.Calculated and observed trends in covalency, Delta values, and first L-->M charge-transfer energies are compared. The conclusion is drawn that the molecular orbital method, in its present formulation, gives a reasonable account of the ground states and low excited states in simple metal complexes

De la naissance à la connaissance

Assister à un spectacle écrit et  mis en scène par Wajdi Mouawad, c’est comme plonger entièrement sa tête dans un livre et y mettre toute son énergie jusqu’à  la résolution finale. Le théâtre qu’il écrit raconte des histoires à la manière d’un roman, avec toutes les qualités que cela requiert. Ses pièces ressemblent à des romans adaptés pour la scène théâtrale, elles ont même des qualités de scènes de cinéma. L’enchaînement des lieux, les changements d’époque, et le mouvement qui prend forme ..

Raplyrikkens potensial i norskfaget

Lyrikken har alltid hatt en sentral plass i norskfaget. Likevel tyder forskning på at dagens litteraturundervisning er lærebokstyrt og at den preges av en skjult litterær kanon. Forskning viser også at norskundervisningen i den videregående skolen er dominert av sakprosaskriving. Med dette kan det tenkes at dagens elever trolig ikke har et nært forhold til lyrikksjangeren generelt. Ifølge forskning rapporterer flere elever også om et uttrykksbehov. Lyrikksjangeren har ekspressive sjangertrekk, og flere teoretikere argumenterer for å ta i bruk samtidslitteratur, og også samtidslyrikk, i norskfaget. Raplyrikken er en del av samtidslitteraturen og også elevenes populærkultur. Et sentralt sjangertrekk er at det lyriske jeget gjennom bruk av språklige og rytmiske valg, skal uttrykke en identitet, tilhørighet, holdninger og selvforståelse. Problemstillingen for denne oppgaven er som følger: Hvilke potensial har raplyrikken i norskfaget? Hensikten med dette prosjektet har vært å utforske raplyrikkens potensial i norskundervisningen. Jeg har også ønsket å undersøke om raplyrikk kan være en måte å øke elevenes engasjement for lyrikksjangeren generelt. I tillegg har prosjektet hatt som siktemål å finne ut om kreative skriveoppgaver i form av raplyrikk, kan stimulere til økt skrivelyst hos elevene. Det har også vært ønskelig å undersøke om raplyrikk kan være en relevant sjanger i norskfagets tematisering av det tverrfaglige temaet «Folkehelse og livsmestring». Dette prosjektet har hatt flere ulike målsettinger, og vil derfor støttes opp av både litteratur- og skrivedidaktisk teori. Den ekspressive skriveteorien, modelltekstdidaktikken og sjangerlæren skaper det teoretiske grunnlaget, sammen med det terapeutiske aspektet ved poesiskriving, litteraturlesing i spenning mellom erfaring og analyse og norskfagets danningsdimensjon. Masteroppgaven baserer seg på en kvalitativ forskningsmetode. For å undersøke raplyrikkens potensial i norskfaget valgte jeg å utføre et raplyrisk skriveverksted i en studiespesialiserende vg1-klasse, hvor elevene til slutt skulle produsere egne raplyriske tekster. I forkant og etterkant av skriveverkstedet ble det utført kvalitative spørreundersøkelser med kvantitativ utforming, som danner datagrunnlag og material som oppgaven baserer seg på. Resultatene viser at 19/26 elever opplevde at det raplyriske skriveverkstedet hadde påvirket holdningene og forholdet deres til lyrikksjangeren i positiv retning, og hele 21/26 elever rapporterte om økt skrivelyst etter at de hadde skrevet egne raptekster. Videre viser resultatene at 23/26 elever opplevde at raplyrikken hjalp dem til å uttrykke følelser og tanker, og 20/26 hevdet at skriveverkstedet hadde gitt dem noe på det personlige plan

Binaural localization and separation techniques

Abstract Based on binaural signals, i.e. the signals observed at the two ears, a listener can localize and recognize different sound sources and then focus on one of these. For decades, researchers have tried to invent a machine that can do the same under similar conditions. Despite all the efforts, the human auditory system is, by far, superior to any machine that has been devised. The topic of this thesis is computational techniques for the localization and separation of sources in binaural signals. In order to give an overview of different areas of research that have considered the problems of source localization and separation, we start with a review of existing techniques. This provides the background for the techniques that we propose subsequently. Binaural Localization The most important cues for localization of sound sources in binaural signals are the level and time differences between the ears. We propose a technique for the joint evaluation of these cues where noisy level difference estimates are combined with less noisy but ambiguous time difference estimates in order to provide accurate azimuth estimates. The proposed technique enables the localization of sources and the tracking of these in dynamic scenes. Head model Based on a study of the level and time differences as function of azimuth angle for different heads, we propose a generic model that is parametrized by the distance between the ears only. This enables the use of the binaural localization technique mentioned above for a listener whose head related transfer functions have not been measured. Binaural separation For the separation of sources we propose a method based on spatial windowing in the azimuth parameter space. Separation of overlapping partials Finally, we propose a technique for the separation of overlapping partials in mixtures of harmonic instruments. The technique is based on the similarity of temporal envelopes between the different partials of a harmonic note

Visualization of Complex Systems

Complex systems are difficult to understand. To aid understanding of complexdynamic systems the field of system dynamics has developed a set of visualizationmethods for graphic representation of the simulation models of complex systems. Theresulting visualizations, however, may sometimes be difficult to understand foraudiences without a background in the scientific investigation of complex dynamicsystems. It is therefore necessary to find new ways of representing complex systemswith the purpose of making them more accessible. This thesis describes how systemdynamic models may be visualized with a particular audience in mind – novicesystem dynamics students. The use of narrative elements and multimedia in thedevelopment of the user interface is explored. A variety of theories and researchfields, such as narrative theory, system dynamics, human computer interaction, andcomputer support for collaboration and learning (CSCL) are utilized in the study. Theproject includes analysis and development of visualizations of system structure,behavior, and narratives that link and explain the relationship between structure andbehavior of complex dynamic systems.Two prototypes of interactive learning environments are developed and evaluated inthe project: The Two-Shower prototype and The Quito prototype. The Two-Showerprototype is based on a small model of a complex system and portrays two showersthat share a hot water tank. The model is a metaphorical model and represents asimple system for resource sharing. The second model is a model of Quito, the capitalof Ecuador, and describes the dynamics of the citizens, tourists, pollution, and themaintenance of Quito’s UNESCO enlisted historic buildings. The Two-Showerprototype is evaluated by usability tests and suggestions for new design are made.The experiences from the development of the Two-Shower prototype are thendiscussed considering how they may be transferred to the Quito prototype, which isbased on a larger model. Being a model of a social system, it portrays issues that aremore complex. Modeling of social systems raises some particular issues regarding choice and representation of variables. The thesis attempts to make bridges betweencomplex system theory, system dynamics, visualization, and learning theory – asrelated to design

Feasibility and acceptability of training community health workers in ear and hearing care in Malawi: a cluster randomised controlled trial.

OBJECTIVE: To assess the feasibility and acceptability of training community health workers (CHWs) in ear and hearing care, and their ability to identify patients with ear and hearing disorders. DESIGN: Cluster randomised controlled trial (RCT). SETTING: Health centres in Thyolo district, Malawi. PARTICIPANTS: Ten health centres participated, 5 intervention (29 CHWs) and 5 control (28 CHWs). INTERVENTION: Intervention CHWs received 3 days of training in primary ear and hearing care, while among control CHWs, training was delayed for 6 months. Both groups were given a pretest that assessed knowledge about ear and hearing care, only the intervention group was given the posttest on the third day of training. The intervention group was given 1 month to identify patients with ear and hearing disorders in their communities, and these people were screened for hearing disorders by ear, nose and throat clinical specialists. OUTCOME MEASURES: Primary outcome measure was improvement in knowledge of ear and hearing care among CHWs after the training. Secondary outcome measures were number of patients with ear or hearing disorders identified by CHWs and number recorded at health centres during routine activities, and the perceived feasibility and acceptability of the intervention. RESULTS: The average overall correct answers increased from 55% to 68% (95% CI 65 to 71) in the intervention group (p<0.001). A total of 1739 patients with potential ear and hearing disorders were identified by CHWs and 860 patients attended the screening camps, of whom 400 had hearing loss (73 patients determined through bilateral fail on otoacoustic emissions, 327 patients through audiometry). Where cause could be determined, the most common cause of ear and hearing disorders was chronic suppurative otitis media followed by impacted wax. The intervention was perceived as feasible and acceptable to implement. CONCLUSIONS: Training was effective in improving the knowledge of CHW in ear and hearing care in Malawi and allowing them to identify patients with ear and hearing disorders. This intervention could be scaled up to other CHWs in low-income and middle-income countries. TRIAL REGISTRATION NUMBER: Pan African Clinical Trial Registry (201705002285194); Results

The El Niño effect on Ethiopian summer rainfall

While El Niño is known to cause failure of Kiremt (boreal summer) rainfall in Ethiopia, the mechanisms are not fully understood. Here we use the ECHAM5 Atmospheric General Circulation Model to investigate the physical link between Pacific sea surface temperature (SST) anomalies and Kiremt rainfall. We compare ECHAM5 simulations forced with reconstructed SST data, to gauge-based rainfall observations and atmospheric reanalysis for the time period of 1961–2009. We perform composite analysis and sensitivity experiments driven only with equatorial Pacific SST anomalies. Our results show warm SST anomalies in the equatorial Pacific drive a corresponding large-scale circulation anomaly with subsidence over Ethiopia in dry Kiremt seasons. Horizontal wind fields show a slow-down of the whole Indian monsoon system with a weaker Tropical Easterly Jet and a weaker East African Low-Level Jet in these summers. These changes can be seen as an anomalous circulation cell over northern Africa with westerlies at 100–200 hPa and easterlies below 500 hPa. Surface easterlies might reduce the moisture inflow from the Atlantic and Congo basin into Ethiopia. This and the general subsidence over the region could explain the reduction in Kiremt rainfall. Our results suggest up to 50% of the Kiremt rainfall anomalies is driven by equatorial Pacific SST variability.publishedVersio

RUPPENTHAL, Jens, Kolonialismus als “Wissenschaft und Technik”. Das Hamburgische Kolonialinstitut 1908 bis 1909

La période coloniale allemande qui prit fin avec la Première Guerre mondiale, bien que de courte durée, a déjà fait l’objet d’une segmentation dans le temps. S’y détache en particulier la phase historique appelée « ère Dernburg » du nom du secrétaire d’État aux colonies Dernburg qui plaida en mai 1907 pour un colonialisme réformé, plus scientifique et raisonné. C’est à cette perspective des « sciences coloniales » que J.R. s’intéresse dans cet ouvrage. Après avoir rappelé l’intérêt accru des ..