Recently, Kadir and Brady proposed a method for estimating probability density functions (PDFs) for digital signals which they call the Nonparametric (NP) Windows method. The method involves constructing a continuous space representation of the discrete space and sampled signal by using a suitable interpolation method. NP Windows requires only a small number of observed signal samples to estimate the PDF and is completely data driven. In this short paper, we first develop analytical formulae to obtain the NP Windows PDF estimates for 1D, 2D, and 3D signals, for different interpolation methods. We then show that the original procedure to calculate the PDF estimate can be significantly simplified and made computationally more efficient by a judicious choice of the frame of reference. We have also outlined specific algorithmic details of the procedures enabling quick implementation. Our reformulation of the original concept has directly demonstrated a close link between the NP Windows method and the Kernel Density Estimator.

Image analysis researchers would benefit considerably by sharing and reusing image processing algorithms. We consider some of the issues that researchers face in trying to provide algorithms in a shareable and reusable form illustrating our approach in the context of medical imaging needs and workflow for colorectal cancer. We consider the use of workflow as a model for developing and reusing components of medical imaging and specifically we consider a solution built using .Net and Windows Workflow Foundation.

This paper investigates the performance benefits of different resource allocation strategies that take advantage of permutation zones specified in IEEE 802.16e-based OFDMA systems. In particular, we propose and investigate the benefits of a sub-zone scheduling approach where each permutation zone is partitioned into sub-zones that are used for scheduling subsets of eligible users according to their prevailing link quality. In the scenarios considered, the proposed sub-zone scheduling approach allows improvements in sector throughputs as high as 80% relative to a baseline IEEE 802.16e-based OFDMA system while maintaining the system outage at acceptable levels.

In this paper, we describe a system for the automatic recognition of isolated handwritten Devanagari characters obtained by linearizing consonant conjuncts. Owing to the large number of characters and resulting demands on data acquisition, we use structural recognition techniques to reduce some characters to others. The residual characters are then classified using the subspace method. Finally the results of structural recognition and feature-based matching are mapped to give final output. The proposed system is evaluated for the writer dependent scenario.

Downlink time division multiplexing is considered for cellular packet-switched systems, in conjunction with scheduling algorithms for fast packet switching across the served users. Additionally, open and closed loop transmit diversity techniques at the base station are considered to improve the spectral efficiency of the resulting system. A study is conducted on the effect of candidate transmit diversity techniques for packet data systems on the overall network data throughput in the presence of scheduling. Contrary to the circuit-switching paradigm, the presented results highlight the conflicting objectives of specific transmit diversity schemes and efficient scheduling and illustrate the impact of the medium access control layer functions on the physical layer performance. The open loop space time spreading technique is shown to offer inferior performance to no transmit diversity under greedy packet scheduling. An appropriate transmit diversity scheme is proposed for the downlink packet-data multiple access.

Packet data is expected to dominate third generation wireless networks, unlike current generation voice networks. This opens up new and interesting problems. Physical and link layer issues have been studied extensively, while resource allocation and scheduling issues have not been addressed satisfactorily.