509 research outputs found
A Unified Scheme for Modular Invariant Partition Functions of WZW Models
We introuduce a unified method which can be applied to any WZW model at
arbitrary level to search systematically for modular invariant physical
partition functions. Our method is based essentially on modding out a known
theory on group manifold by a discrete group .
We apply our method to with , and to
models, and obtain all the known partition functions and some
new ones, and give explicit expressions for all of them.Comment: 30 page ,SUTDP/11/93/72 Department of Physics, Sharif University of
Technolog
Joint Spectrum Sensing and Resource Allocation for OFDM-based Transmission with a Cognitive Relay
In this paper, we investigate the joint spectrum sensing and resource
allocation problem to maximize throughput capacity of an OFDM-based cognitive
radio link with a cognitive relay. By applying a cognitive relay that uses
decode and forward (D&F), we achieve more reliable communications, generating
less interference (by needing less transmit power) and more diversity gain. In
order to account for imperfections in spectrum sensing, the proposed schemes
jointly modify energy detector thresholds and allocates transmit powers to all
cognitive radio (CR) subcarriers, while simultaneously assigning subcarrier
pairs for secondary users (SU) and the cognitive relay. This problem is cast as
a constrained optimization problem with constraints on (1) interference
introduced by the SU and the cognitive relay to the PUs; (2) miss-detection and
false alarm probabilities and (3) subcarrier pairing for transmission on the SU
transmitter and the cognitive relay and (4) minimum Quality of Service (QoS)
for each CR subcarrier. We propose one optimal and two sub-optimal schemes all
of which are compared to other schemes in the literature. Simulation results
show that the proposed schemes achieve significantly higher throughput than
other schemes in the literature for different relay situations.Comment: EAI Endorsed Transactions on Wireless Spectrum 14(1): e4 Published
13th Apr 201
Recommending Stack Overflow Posts for Fixing Runtime Exceptions using Failure Scenario Matching
Using online Q&A forums, such as Stack Overflow (SO), for guidance to resolve
program bugs, among other development issues, is commonplace in modern software
development practice. Runtime exceptions (RE) is one such important class of
bugs that is actively discussed on SO. In this work we present a technique and
prototype tool called MAESTRO that can automatically recommend an SO post that
is most relevant to a given Java RE in a developer's code. MAESTRO compares the
exception-generating program scenario in the developer's code with that
discussed in an SO post and returns the post with the closest match. To extract
and compare the exception scenario effectively, MAESTRO first uses the answer
code snippets in a post to implicate a subset of lines in the post's question
code snippet as responsible for the exception and then compares these lines
with the developer's code in terms of their respective Abstract Program Graph
(APG) representations. The APG is a simplified and abstracted derivative of an
abstract syntax tree, proposed in this work, that allows an effective
comparison of the functionality embodied in the high-level program structure,
while discarding many of the low-level syntactic or semantic differences. We
evaluate MAESTRO on a benchmark of 78 instances of Java REs extracted from the
top 500 Java projects on GitHub and show that MAESTRO can return either a
highly relevant or somewhat relevant SO post corresponding to the exception
instance in 71% of the cases, compared to relevant posts returned in only 8% -
44% instances, by four competitor tools based on state-of-the-art techniques.
We also conduct a user experience study of MAESTRO with 10 Java developers,
where the participants judge MAESTRO reporting a highly relevant or somewhat
relevant post in 80% of the instances. In some cases the post is judged to be
even better than the one manually found by the participant
Unusual Behaviour of an Earth-Rockhill Dam
The post-construction behaviour of a 47.5 m high and 700 m long earth-rockfill dam, located in northwestern Iran, is described. The embankment dam is founded on Tertiary rock on both abutments, but in the river channel it rests on alluvial deposits of variable composition and thickness. Since the first impoundment, the dam has undergone large deformations, both in vertical and in horizontal directions. These have resulted in unusual differential settlements, visible along the crest, and have produced wide longitudinal cracks in the asphalt pavement of the crest road. The principle features of the dam are described and selected monitoring results of the crest movements for a sixteen year period are presented. Based on the analysis of the available data and taking into account the geotechnical characteristics of the foundation and the fill materials, an interpretation of the unusual behaviour has been attempted
Recommended from our members
Predictive markers for humoral influenza vaccine response in patients with common variable immunodeficiency (CVID)
BACKGROUND: A subgroup of patients with common variable immunodeficiencies (CVID) responds to vaccination. The aim of the study was to try to identify predictive markers for those who developed a humoral immune response after influenza vaccination. METHODS: 48 patients with CVID (29 females, 19 males, mean age 59.4 years) were vaccinated with the A(H1N1) influenza vaccine PandemrixÂź and boosted after one month. Blood samples were collected prior to each vaccination and two months later. Patients with a 4-fold titer increase of the hemagglutinin inhibition test (â„ 1:40) were considered responders and compared to non-responders for clinical, immunological and genetic markers. RESULTS: Eight (16.7%) patients responded to the vaccination. A significantly higher proportion of the responders, who showed a Euroclass SmB-Trnorm21norm profile (p=0.03) with a post-germinal center B cell pattern (p=0.04) in blood, suffered from enteropathies (p=0.04) as compared to non-responders. Bronchiectasis on the other hand, was exclusively found among non-responders (n=7), as was autoimmune cytopenia (n=5). Non-responders with a Euroclass SmB-21lowTrnorm profile (p=0.02), had a significantly higher prevalence of progressive antibody deficiency (p=0.048) and, at diagnosis, a higher mean serum IgM level (p=0.03), a lower mean serum IgG1 level (p=0.007), an expansion of absolute counts of cytotoxic CD8+ T-cells (p=0.033) and an increased proportion of memory CD8+ T-cells (p=0.044) in blood. CVID associated HLA markers were not detected in non-responders (p=0.03). CONCLUSION: About one-fifth of the CVID patients achieved protective antibody levels after A(H1N1) vaccination and selected clinical and immunological markers were identified that may predict a positive outcome of influenza vaccination
Temporal changes in importance of quality of life domains: a longitudinal study in community-dwelling Swiss older people.
Population aging is a global phenomenon requiring interventions to improve quality of life (QoL), a subjective and dynamic concept. Such interventions should be based on QoL domains considered as important from older people's viewpoint. It is unclear whether and how much these domains may vary over time as people age. This study aims to assess the importance of QoL domains, their pattern and determinants of change among the non-institutionalized older population over a 5-year period.
This longitudinal study included community-dwelling older adults (N = 1947, aged 68-77 years at baseline) from the Lausanne cohort 65+. In 2011 and 2016, participants rated the importance of 28 QoL items in seven domains. The difference between scores (0-100) of importance attributed to each QoL domain between two assessments was calculated and used as a dependent variable to assess the associations with covariates in multivariable analysis for each domain.
Importance scores slightly but significantly decreased in five of the seven QoL domains. Despite the majority of participants did not modify their ranking of importance for each QoL domain between the two time points, the proportion of change was still substantial. Bivariate and multivariable analyses showed that education and to a lesser extent age, living arrangement and morbidity, were associated with decrease in the importance of specific QoL domains; characteristics indicating vulnerability (e.g., low education or morbidity) were associated with a decline in the importance.
Although aging individuals modified the importance they give to the seven QoL domains, at population level, changes in opposite directions overall resulted in only small decline; importance seems less stable over time among individuals with vulnerable sociodemographic and health profiles
Change in quality of life among community-dwelling older adults: population-based longitudinal study.
This population-based study aimed to determine 5-year change in multidimensional QoL among community-dwelling older people, and to identify predictors of QoL change among demographic, socioeconomic, and health characteristics.
Data of the 2011 and 2016 annual assessments of 1845 older men and women (age range 68-77Â years) from the Lc65â+âcohort study were used. QoL was assessed using a 28-item instrument yielding a QoL overall score and seven domain-specific QoL subscores. Additional ratings of QoL included a single item (excellent; very good; good; fair; poor), expected QoL in 1 year (better; worse; same as today), and retrospective assessment of QoL 5-year change (better; worse; same as 5 years ago). The predictors of 5-year change in the QoL score were assessed using linear regression, controlling for baseline QoL score.
All prospective and retrospective indicators of QoL converged towards a slight deterioration over 5 years. QoL subscores significantly decreased in domains "Close entourage" (Pâ=â0.004), "Social and cultural life" (Pâ<â0.001), "Esteem and recognition" (Pâ=â0.001), "Health and mobility" (Pâ<â0.001), and "Autonomy" (Pâ<â0.001), whereas "Material resources" (Pâ=â0.345) and "Feeling of safety" (Pâ=â0.380) remained stable. A stronger decrease in QoL was observed in the most vulnerable profiles at baseline in terms of demographic, socioeconomic, and health characteristics. Changes in depressive symptoms and in disability-either worsening or improving-predicted QoL change in the expected direction.
Age-related decline in QoL may be limited through the prevention of disability and depressive symptoms, and more generally by devoting special attention to vulnerable profiles
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