2,686 research outputs found

    Measurement of the ZZ production cross section and limits on anomalous neutral triple gauge couplings in proton-proton collisions at sqrt{s} =7 TeV with the ATLAS detector

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    A measurement of the ZZ production cross section in proton-proton collisions at sqrt{s} = 7 TeV using data collected by the ATLAS experiment at the LHC is presented. In a data sample corresponding to an integrated luminosity of 1.02fb-1, 12 events containing two Z boson candidates decaying to electrons and/or muons were observed. The expected background contribution is 0.3^{+0.9}_{-0.3} (stat) ^{+0.4}_{-0.3} (syst) events. The total cross section for on-shell ZZ production has been determined to be \sigma_{ZZ}_{tot}= 8.4^{+2.7}_{-2.3}(stat) ^{+0.4}_{-0.7}(syst)\pm 0.3 (lumi) pb$ and is compatible with the Standard Model expectation of 6.5^{+0.3}_{-0.2} pb calculated at the next-to-leading order in QCD. Limits on anomalous neutral triple gauge boson couplings are derived.Comment: 8 pages, Proceedings of the DPF-2011 Conference, Providence, RI, August 8-13, 201

    Understanding The Role Of Social Capital In Expertise Coordination In Information Systems Development (isd) Teams

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    Information system development (ISD) project is a knowledge-intensive teamwork process which requires members to coordinate their expertise to generate the final outcome. Breakdown or coordination and insufficient knowledge integration have been reported as critical factors which lead to ISD project failure. Most existing coordination literature focus on the effect of administrative coordination mechanisms toward project performance which hints that more efforts are needed to understand expertise coordination and explore ways to improve it. Addressing the above issues, two studies in this dissertation attempt to understand expertise coordination within the IS development team based on social capital perspective. The first study, based on intention-behavior literature, knowledge management research, and Gerwin\u27s (2004) coordination model, investigates relationships among willingness, competence, and actual expertise coordination. The relationships between expertise coordination and teamwork outcomes are also examined. The second study incorporates social capital theory and examines (1) dependencies among three dimensions of social capital and (2) linkage between social capital and expertise coordination. Data collected from more than five hundred information systems project team members was used to test the proposed hypotheses. The analysis results confirmed most of the hypotheses. This dissertation contributes to coordination, project management, and team mental model research through many perspectives. In each study, directions for management practice and future research are discussed

    Hydrocarbon Seepage at Campeche-Sigsbee Salt Province, Southern Gulf of Mexico (Detection, Mapping, and Seafloor Manifestation)

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    Hydrocarbon seepage is a process during which hydrocarbon fluids are emitted from the seafloor into the water column. This phenomenon has been observed globally from continental margins to the deep abyssal. Hydrocarbon seepage has significant impacts on the marine environment such as (a) influence on sediment composition and dynamics at the seafloor, (b) increasing the habitat heterogeneity on seep biodiversity and (c) contributes to the global carbon cycle. However, the occurrence, distribution, and dynamics of hydrocarbon seepage in the marine environment, especially in the deep ocean remains unclear due to limited investigation. The northern Gulf of Mexico is a well-known prolific petroleum-producing region where numerous gas and oil emissions, associated with salt tectonism, have been observed. The Campeche-Sigsbee salt province in the southern GoM is considered to be an analog to the salt province in the northern GoM, but there has been very little research conducted in this region. Based on the occurrence of natural oil slicks on the sea surface resolved by satellite images, previous studies suggested that there is a widespread distribution of oil seeps in the Campeche-Sigsbee salt province. However, there is still a lack of direct evidence for the presence and the distribution of gas emissions. In addition to gas and oil seepage, Chapopote asphalt volcanism, a novel type of hydrocarbon seepage was first introduced in 2003. Since then, submarine asphalt deposits have attracted considerable research interest. This study aims to have a comprehensive understanding of the hydrocarbon seepage system and dynamics in the southern GoM. The objectives are to investigate the distribution of gas emissions and to understand the controlling factors on the distribution. Furthermore, detailed investigations were carried out at Challenger Knoll and Mictlan Knoll to gain a better understanding of the diverse hydrocarbon seepage system including gas and oil emissions, as well as asphalt deposits. Consequently, the research questions about the fate of the methane bubbles and the quantity of gas bubble released from gas emission site are finally addressed in this study. During research cruise M114 of R/V METEOR, a multidisciplinary approach was conducted, including hydroacoustic surveys, visual seafloor observations, and sampling of gas bubbles. Ship-based multibeam echosounder was used for seafloor bathymetry, backscatter and water column flare mapping in the Campeche-Sigsbee salt province. In addition, multibeam echosounder mounted on Autonomous Underwater Vehicle (AUV) was utilized to obtain high-resolution seafloor bathymetry, backscatter, and water column data at Mictlan Knoll. Remotely Operated Vehicle (ROV) and TV-sled were applied for investigating and documenting seafloor manifestations of hydrocarbon seepage at the seafloor. Gas bubbles were collected by pressure-tight gas bubble samplers operated by ROV at the seafloor of Mictlan Knoll for gas analyses, quantification of gas bubble emissions, and finally gas flux calculation. In summary, gas emissions are found in large numbers in the Campeche-Sigsbee salt province. Their distributions are controlled by the present geological structures. The case study in the Sigsbee Knolls suggests that the edges of flat-top knolls might provide an effective migration pathway for hydrocarbons. As there is no direct evidence for the presence of current oil seepage in the Sigsbee Knolls, we suggested that oil seepage occurs intermittently. Gas, oil seepage and asphalt volcanism are found to occur close together at the Mictlan Knoll, indicating that this diverse hydrocarbon seepage system might be a common phenomenon in the Campeche Knolls. This thesis shows the complex association between the dynamics of diverse hydrocarbon seepage and the geological controls in the southern GoM

    Defying Gravity: Migrant Children Education System in Beijing, China policies, NGOs, and market as factors

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    Special Studies Experience, Summer 2012 -- Beijing, Chinahttp://deepblue.lib.umich.edu/bitstream/2027.42/110200/1/Poster_Hsu.Chih-Chieh.pd

    Rhythm-Flexible Voice Conversion without Parallel Data Using Cycle-GAN over Phoneme Posteriorgram Sequences

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    Speaking rate refers to the average number of phonemes within some unit time, while the rhythmic patterns refer to duration distributions for realizations of different phonemes within different phonetic structures. Both are key components of prosody in speech, which is different for different speakers. Models like cycle-consistent adversarial network (Cycle-GAN) and variational auto-encoder (VAE) have been successfully applied to voice conversion tasks without parallel data. However, due to the neural network architectures and feature vectors chosen for these approaches, the length of the predicted utterance has to be fixed to that of the input utterance, which limits the flexibility in mimicking the speaking rates and rhythmic patterns for the target speaker. On the other hand, sequence-to-sequence learning model was used to remove the above length constraint, but parallel training data are needed. In this paper, we propose an approach utilizing sequence-to-sequence model trained with unsupervised Cycle-GAN to perform the transformation between the phoneme posteriorgram sequences for different speakers. In this way, the length constraint mentioned above is removed to offer rhythm-flexible voice conversion without requiring parallel data. Preliminary evaluation on two datasets showed very encouraging results.Comment: 8 pages, 6 figures, Submitted to SLT 201
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