co-channel interference is a major factor in limiting the capacity and link quality in cellular communications. as the co-channel interference is modeled by lognormal distribution, sum of the co-channel interferences of neighboring cells is represented by the sum of lognormal random variables (rvs) which has no closed-form expression. assuming independent, identically distributed (iid) rvs, the...

‎we characterize those groups $g$ and vector spaces $v$ such that $v$ is a faithful irreducible $g$-module and such that each $v$ in $v$ is centralized by a $g$-conjugate of a fixed non-identity element of the fitting subgroup $f(g)$ of $g$‎. ‎we also determine those $v$ and $g$ for which $v$ is a faithful quasi-primitive $g$-module and $f(g)$ has no regular orbit‎. ‎we do use these to show in ...

This study examined various model combinations and calibration procedures for mixed format tests under different item response theory (IRT) models and calibration methods. Using real data sets that consist of both dichotomous and polytomous items, nine possibly applicable IRT model mixtures and two calibration procedures were compared based on traditional and alternative goodnessof-fit statisti...

Grazing X-ray reflectometry allows the analysis of thin layer stacks. The fitting of the reflectivity curve by a trial and error method can be used in order to determine the parameters of the films. Fourier analysis of the experimental reflectivity can directly give a rough determination of the profit index. Application to real examples shows the validity of the method.

Sound coding strategies for cochlear implants have evolved over the past 30 years with advances in research and technology. Processing schemes have transitioned from the delivery of a diffuse, broad signal in single channel devices to the transmission of detailed sound information to multi-channel devices. This evolution has involved the addition of more channels and more parameter options for ...

We consider longitudinal clinical data for HIV patients undergoing treatment interruptions. We use a nonlinear dynamical mathematical model in attempts to fit individual patient data. A statistically-based censored data method is combined with inverse problem techniques to estimate dynamic parameters. The predictive capabilities of this approach are demonstrated by comparing simulations based o...

Motor adaptation is a form of learning to re-establish desired movements in novel situations. To probe motor adaptation, one can replicate such conditions experimentally by imposing sustained perturbation during movement. Exposure perturbations initially causes an abrupt change relevant performance variables, followed gradual return baseline behaviour. The resulting time series exhibit persiste...

A live-attenuated vaccine against herpes zoster (HZ) has been approved for use, on the basis of a large-scale clinical trial that suggests that the vaccine is safe and efficacious. This study uses a Markov cohort model to estimate whether routine vaccination of the elderly (60+) would be cost-effective, when compared with other uses of health care resources. Vaccine efficacy parameters are esti...

When estimating the effect of treatment on HIV using data from observational studies, standard methods may produce biased estimates due to the presence of time-dependent confounders. Such confounding can be present when a covariate, affected by past exposure, is both a predictor of the future exposure and the outcome. One example is the CD4 cell count, being a marker for disease progression for...