Building a visual overview of temporal event sequences with an optimal level-of-detail (i.e. simplified but informative) is an ongoing challenge - expecting the user to zoom into every important aspect of the overview can lead to missing insights. We propose a technique to build a multilevel overview of event sequences, whose granularity can be transformed across sequence clusters (vertical level-of-detail) or longitudinally (horizontal level-of-detail), using hierarchical aggregation and a novel cluster data representation Align-Score-Simplify. By default, the overview shows an optimal number of sequence clusters obtained through the average silhouette width metric - then users are able to explore alternative optimal sequence clusterings. The vertical level-of-detail of the overview changes along with the number of clusters, whilst the horizontal level-of-detail refers to the level of summarization applied to each cluster representation. The proposed technique has been implemented into a visualization system called Sequence Cluster Explorer (Sequen-C) that allows multilevel and detail-on-demand exploration through three coordinated views, and the inspection of data attributes at cluster, unique sequence, and individual sequence level. We present two case studies using real-world datasets in the healthcare domain: CUREd and MIMIC-III; which demonstrate how the technique can aid users to obtain a summary of common and deviating pathways, and explore data attributes for selected patterns.

This paper investigates the performance of a weighted proportional fair (WPF) based resource allocation algorithm for future multi-user (MU) multiple-input multiple-output (MIMO) orthogonal frequency-division multiple-access (OFDMA) systems with frequency-selective broadband channels. In future networks algorithms should be designed to allocate the system's resources (time, frequency, space and power) in a manner that exploits multi-user diversity and ensures each user is treated fairly. The proposed algorithm extends the original proportional fair (PF) scheme, which was designed for single-antenna single-carrier systems, to the MIMO-OFDMA downlink such that individual user's quality of service (QoS) requirements are satisfied in terms of requested bit-rate and bit error rate (BER). Monte Carlo simulation results indicates that extending the algorithm to a frequency- and space-division network produces the desirable characteristics of a fair and efficient algorithm