Estimating medical costs from a transition model

Nonparametric estimators of the mean total cost have been proposed in a variety of settings. In clinical trials it is generally impractical to follow up patients until all have responded, and therefore censoring of patient outcomes and total cost will occur in practice. We describe a general longitudinal framework in which costs emanate from two streams, during sojourn in health states and in transition from one health state to another. We consider estimation of net present value for expenditures incurred over a finite time horizon from medical cost data that might be incompletely ascertained in some patients. Because patient specific demographic and clinical characteristics would influence total cost, we use a regression model to incorporate covariates. We discuss similarities and differences between our net present value estimator and other widely used estimators of total medical costs. Our model can accommodate heteroscedasticity, skewness and censoring in cost data and provides a flexible approach to analyses of health care cost.Comment: Published in at http://dx.doi.org/10.1214/193940307000000266 the IMS Collections (http://www.imstat.org/publications/imscollections.htm) by the Institute of Mathematical Statistics (http://www.imstat.org

An algorithm for optimal network planning and frequency channel assignment in indoor WLANs

The increased use of wireless local area networks has led to an increased interference and a reduced performance, as a high amount of access points are often operating on the same frequency channel. This paper presents a network planning algorithm that minimizes the number of access points required for a certain throughput and optimizes the frequency allocated to each AP, leading to reduced interference. The network planning algorithm is based on a heuristic and the frequency planning algorithm on a combination of a greedy algorithm and a Vertex-Coloring-Based Approach. The algorithm provides a good performance and has a limited computation time

Energy Network Communications and Expandable Control Mechanisms

A modular, expandable network requiring little or no calibration is something that is well sought after and would offer great benefits when used for distributed energy generation. Intelligent and adaptive control of such a network offers stability of supply from intermittent sources which, to date, has been hard to achieve. Key to the effective use of such control systems is communications, specifically the exchange of commands and status information between the control systems and the attached devices. Power-line communications has been used in various applications for years and would offer a good mechanism for interconnecting devices on a power grid without the expense of laying new cabling. By using clusters of devices managed by an IEMS (Intelligent Energy Management System) in a branching network fashion (not unlike the grid itself) it would be possible to manage large numbers of devices and high speed with relatively low bandwidth usage increasing the usable range of transmission. Implications of this include improving network efficiency through managed power distribution and increased security of supply

Path-following analysis of the dynamical response of a piecewise-linear capsule system

Acknowledgements The first author has been supported by a Georg Forster Research Fellowship granted by the Alexander von Humboldt Foundation, GermanyPeer reviewedPreprin

Real-time computer-generated hologram by means of liquid-crystal television spatial light modulator

A novel use of liquid-crystal television (LCTV) is described. It is shown that, if the phase nonuniformity of the LCTV is corrected by a liquid gate, then a simple computer-generated hologram can be written and coherently reconstructed

Pseudonondiffracting slitlike beam and its analogy to the pseudonondispersing pulse

A new nonspreading beam is proposed for the case in which diffraction occurs only in one transverse coordinate. The beam has the shape of a pulse in one dimension and is constant in the other (slitlike shape). The intensity of the pulse’s peak remains almost constant along a finite interval on the propagation axis. The proposed beam is analyzed and demonstrated experimentally. The analogy between this beam and the temporal pulse in a dispersive medium is discussed