The Medical Segmentation Decathlon

International challenges have become the de facto standard for comparative assessment of image analysis algorithms given a specific task. Segmentation is so far the most widely investigated medical image processing task, but the various segmentation challenges have typically been organized in isolation, such that algorithm development was driven by the need to tackle a single specific clinical problem. We hypothesized that a method capable of performing well on multiple tasks will generalize well to a previously unseen task and potentially outperform a custom-designed solution. To investigate the hypothesis, we organized the Medical Segmentation Decathlon (MSD) - a biomedical image analysis challenge, in which algorithms compete in a multitude of both tasks and modalities. The underlying data set was designed to explore the axis of difficulties typically encountered when dealing with medical images, such as small data sets, unbalanced labels, multi-site data and small objects. The MSD challenge confirmed that algorithms with a consistent good performance on a set of tasks preserved their good average performance on a different set of previously unseen tasks. Moreover, by monitoring the MSD winner for two years, we found that this algorithm continued generalizing well to a wide range of other clinical problems, further confirming our hypothesis. Three main conclusions can be drawn from this study: (1) state-of-the-art image segmentation algorithms are mature, accurate, and generalize well when retrained on unseen tasks; (2) consistent algorithmic performance across multiple tasks is a strong surrogate of algorithmic generalizability; (3) the training of accurate AI segmentation models is now commoditized to non AI experts

From optimal search theory to sequential paging in cellular networks

We propose a novel paging strategy based on the theory of optimal search with discrete efforts. When compared to conventional paging methods, the proposed scheme increases the mobile station discovery rate while decreasing the average number of times that a mobile station has to be paged in a location area. The proposal is fully compatible with existing cellular structures, and requires minimal computational power in the mobile switching centers.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Wavelet Based Speech Coding Using Orthogonal Matching Pursuit

A novel waveform approximation called Orthogonal Matching Pursuit [1] (OMP) has been exploited to represent a speech waveform with a set of complex coefficients. The OMP algorithm proved to be quite effective in approximating waveforms that have their energy concentrated in a short ranges of frequency. The spectrum of speech signals is usually well-localized in frequency and therefore OMP is a suitable tool for the purpose of speech coding. The algorithm has been applied to a standard test signal. I Introduction Speech coding methods can be categorized into two major groups: those based on reconstructing the speech waveform (waveform coders), and those that build a speech production model to reproduce the speech (voice coders or vocoders). Waveform coders, themselves, can be divided into two groups: (i) time--domain waveform and (ii) spectral--domain waveform coders. The former takes advantage of the fact that speech is a semi periodic signal meaning that it is periodic over short tim..

Stochastic Control of Handoffs in Cellular Networks

A Dynamic Programming formulation is used to obtain an optimal strategy for the handoff problem in cellular radio systems. The formulation includes the modeling of the underlying randomness in received signal strengths as well as the movements of the mobile. The cost function is designed such that there is a cost associated with switching and a reward for improving the quality of the call. The optimum decision is characterized by a threshold on the difference between the measured power that the mobile receives from the base stations. Also we study the problem of choosing the "best" fixed threshold that minimizes the cost function. The performance of the optimal and suboptimal strategies are compared. I. Introduction W IRELESS networks are experiencing rapid growth, a trend likely to continue in the foreseeable future. In both micro and macro cellular networks a key issue for efficient operation is the problem of handoffs. A call on a portable/mobile which leaves one cell (radio cover..

Optimal Control of Handoffs in Wireless Networks

A Dynamic Programming formulation is used to obtain an optimal strategy for the handoff problem in cellular radio systems. The formulation includes the modeling of the underlying randomness in received signal strengths and of the mobile's movements. The cost function is designed such that there is a cost associated with switching and a reward for improving the quality of the call. The optimum decision is characterized by a threshold on the difference between the measured power that the mobile receives from the base stations. Also we study the problem of choosing the "best" fixed threshold that minimizes the cost function. The performance of the optimal and suboptimal strategies are compared. I Introduction Wireless networks are experiencing rapid growth, a trend likely to continue into the foreseeable future. In both micro and macro cellular networks, a key issue for efficient operation is the problem of handoffs. A call on a portable/mobile which leaves one cell (radio coverage area..

From Theory of Optimal Search to Sequential Paging in Cellular Networks

We propose a novel paging strategy based on the theory of optimal search with discrete effort. When compared to conventional paging methods, the proposed scheme increases the mobile station discovery rate while decreasing the average number of times that a mobile station has to be paged in a location area. The proposal is fully compatible with existing cellular structure and requires minimal computational power in the mobile switching centers. I. Introduction In order to make a more efficient use of limited wireless resources, emerging personal communication services (PCS) require much smaller cells (microcells and picocells) than those used in conventional cellular networks. Tracking the mobile stations will become a challenging task as the cell sizes shrink and the number of cells increases. In order to ensure reliable communication, a mobile station has to send/receive signaling messages from/to the base station. Depending on the system design, signaling messages serve various purp..