Multilevel statistical models have become increasingly popular among public health researchers over the past decade. Yet the enthusiasm with which these models are being adopted may obscure rather than solve some problems of statistical and substantive inference. We discuss the three most common applications of multilevel models in public health: (a) cluster-randomized trials, (b) observational...

An experiment was conducted comparing multilevel selection in Japanese quail for 43 days weight and survival with birds housed in either kin (K) or random (R) groups. Multilevel selection significantly reduced mortality (6.6% K vs. 8.5% R) and increased weight (1.30 g/MG K vs. 0.13 g/MG R) resulting in response an order of magnitude greater with Kin than Random. Thus, multilevel selection was e...

The need for high power apparatus in industry has increased in recent years. Multilevel inverters have developed as easy alternatives for such power requirements. Multilevel inverters consist of a group of semiconductor switches and a set of voltage source components like capacitors or independent sources. The basic concept of these inverters depends on using this series of switches and sources...

The logistic person response function (PRF) models the probability of a correct response as a function of the item locations. Reise (2000) proposed to use the slope parameter of the logistic PRF as a person-fit measure. He reformulated the logistic PRF model as a multilevel logistic regression model and estimated the PRF parameters from this multilevel framework. An advantage of the multilevel ...

The emerging communication applications such as IPTV, VoIP, infotainment, interactive games, and Internet access might dictate very high reliability and availability in future fiber access networks. We present an easy-to-use software tool, called NetExpert, designed to simplify the network planning, design and optimization processes and save valuable time preparing network configurations that p...

 The advent of the transformerless multilevel inverter topology has brought forth various pulse width modulation (PWM) schemes as a means to control the switching of the active devices in each of the multiple voltage levels in the inverter. An analysis of how existing multilevel carrier-based PWM affects switch utilization for the different levels of a diode-clamped inverter is conducted. Two ...

| Multilevel models are designed to deal with studies on data that contain hierarchical structures and are becoming increasingly important in many elds of research. Since they are limited to parametric models, in practice only linear multilevel models are used. We present a nonlinear multilevel approach to investigate nonlinearity in relations. This model is based on nonlinear feed-forward netw...

Although the state space approach for estimating multilevel regression models has been well established for decades in the time series literature, it does not receive much attention from educational and psychological researchers. In this article, we (a) introduce the state space approach for estimating multilevel regression models and (b) extend the state space approach for estimating multileve...

A formal theory of multilevel systems is needed for modelling the outcomes of policy. The dynamics of social systems are coupled between levels and models that do not reflect this are incomplete and a poor basis for policymaking. The structures developed here are necessary for the new kinds of models and computer simulations needed to support policy makers as they tackle the problems of an incr...

Research in several new topologies of Multilevel inverter(MLI) has been carried out rapidly day by day. Recently several topologies have been introduced achieving higher levels with reduced device couns and DC sources .In this paper a new hybrid symmetric MLI is proposed .This topology has reduced number of controlled switches, Dc sources and numbers of capacitors which are very less compared t...