Using mobile phones for accessing the Internet has become a standard use case of such devices, nowadays even more important than the good old phone call.WiFi at home or public ones allow for a low-cost or even unpaid access to the virtual world of the Internet.But, as we will show, this is only true to some degree in terms of monetary cost.One thing we're paying a lot with is the loss of our privacy.In this paper, we will show how easily and cheap potential attackers can track your mobile phone and, thus, you via data it sends all the time, so-called probe requests.Additionally we show by experimental data how this tracking can be used for traffic jam analysis on roads.

In some cases, tasks may be allowed to migrate from one processor to another, e.g., Due to hardware failures or for workload balancing. If a mixed-criticality setting is considered, it is necessary to decide whether new tasks with different levels of criticality may be accepted by a processor without compromising the already running tasks. Since this decision has to be taken on-line, there is a need for fast but yet accurate schedulability tests for mixed-criticality systems. In this paper, we consider that the EDF-VD algorithm is used to schedule tasks on the different processors. EDF-VD assigns virtual deadlines to high-criticality tasks, i.e., It uniformly downscales their real deadlines, to account for a potential increase in their execution demand. A deadline scaling factor is hence computed for the whole processor. However, in the case where the increase in computation demand strongly differs from one task to another, scaling deadlines uniformly makes EDF-VD incur pessimism. Of course, a scaling factor can be computed for every single task, however, this leads to a considerably more complex algorithm which cannot be used in an on-line setting. As a result, we propose an intermediate solution by introducing a bi-level deadline scaling. This way, high-criticality tasks that experience a small increase of workload are assigned one scaling factor, whereas tasks with a large increase of workload are assigned a separate scaling factor. Our experiments show that the proposed approach dominates the original EDF-VD algorithm while it does not increase complexity allowing for constant-time admission control in mixed-criticality systems.

The algorithm Earliest Deadline First with Virtual Deadlines (EDF-VD) was recently proposed to schedule mixed-criticality task sets consisting of high-criticality (HI) and low-criticality (LO) tasks. EDF-VD distinguishes between HI and LO mode. In HI mode, the HI tasks may require executing for longer than in LO mode. As a result, in LO mode, EDF-VD assigns virtual deadlines to HI tasks (i.e., it uniformly downscales deadlines of HI tasks) to account for an increase of workload in HI mode. Different schedulability conditions have been proposed in the literature; however, the schedulability region to fully characterize EDF-VD has not been investigated so far. In this paper, we review EDF-VD's schedulability criteria and determine its schedulability region to better understand and design mixed-criticality systems. Based on this result, we show that EDF-VD has a schedulability region being around 85% larger than that of the Worst-Case Reservations (WCR) approach.

Contrary to the optimal scheduling algorithm Earliest Deadline First (EDF), Rate-Monotonic Scheduling (RMS) can lead to non-schedulable task sets for total utilizations below 1 on a uniprocessor. The quantification of this deficiency has been a topic in real-time science for a long time. We show weaknesses of the scheduling algorithm metrics breakdown utilization, utilization upper bound, and numerical optimality degree. Finally, we suggest a new measure of schedulability called Efficiency and calculate its bounds. It turns out that numerical optimality degree might be too optimistic depending on the assumed total utilization distribution. The main results are the application of a power-law total utilization distribution to quantify the RMS-to-EDF Efficiency and a step-by-step derived lower bound of this Efficiency. We apply a differential analysis of schedulability.

We suggest an improvement to the RMST assignment scheme by Burchard et al., a heuristics for finding approximate solutions to the NP--complete problem of MP scheduling of RT tasks.

For Rate-monotonic Scheduling (RMS) on uniprocessor, there is a steady transition between the two extremes Liu/Layland worst case and simply periodic task set (best case) in terms of utilization bound. The degree of harmonicity is only based on period ratios. Hence, scale invariance is a required property of an appropriate period similarity measure. A standard approach to describe harmonicity is based on the linear range ß of S values, the fractional parts of period logarithms [1]. But linear range is not scale-invariant. We suggest to replace it by circular range in order to obtain better and more consistent utilization bounds.