One table to count them all: parallel frequency estimation on single-board computers

Sketches are probabilistic data structures that can provide approx- imate results within mathematically proven error bounds while using orders of magnitude less memory than traditional approaches. They are tailored for streaming data analysis on architectures even with limited memory such as single-board computers that are widely exploited for IoT and edge computing. Since these devices offer multiple cores, with efficient parallel sketching schemes, they are able to manage high volumes of data streams. However, since their caches are relatively small, a careful parallelization is required. In this work, we focus on the frequency estimation problem and evaluate the performance of a high-end server, a 4-core Raspberry Pi and an 8-core Odroid. As a sketch, we employed the widely used Count-Min Sketch. To hash the stream in parallel and in a cache-friendly way, we applied a novel tabulation approach and rearranged the auxiliary tables into a single one. To parallelize the process with performance, we modified the workflow and applied a form of buffering between hash computations and sketch updates. Today, many single-board computers have heterogeneous processors in which slow and fast cores are equipped together. To utilize all these cores to their full potential, we proposed a dynamic load-balancing mechanism which signif- icantly increased the performance of frequency estimation

Red Cell Distribution Width and Neutrophil/lymphocyte Ratio in Coronary Bare Metal Stent Restenosis: Red Cell Distribution Width and Neutrophil/lymphocyte Ratio in Stent Restenosis

Background Coronary stents are commonly used to treat obstructive coronary artery disease. It is currently difficult to reliably predict in-stent restenosis. The aim of this study was to examine the relationship between bare metal stent restenosis and red cell distribution width (RDW), neutrophil/lymphocyte ratio (N/L ratio). It was the first study that used a control group with a normal coronary angiogram. Methods We enrolled patients who underwent coronary angiography between June 2012 and September 2013 in our center. We enrolled a cohort of 210 consecutive patients, of which 130 had a coronary artery stent and 80 had a normal coronary angiogram. Results The mean age of the study group was 62 (38-86) years. The mean RDW levels of patient group with no-restenosis were significantly higher than the control group but there was no significant difference between the mean RDW levels of the restenosis group and the other subgroups (14.9 (11.7-17.6), 15.5 (10.9-20.4), 15.4 (11.7-20.1), respectively). N/L ratio was significantly higher in patients with stent restenosis 2.32(1.49-5.35) compared to the other two groups whereas there was no significant difference between the control group and non-restenosis group with respect to N/L ratio. (1.71(0.84-7.89), and 2.09(0.89-9.15), respectively). Conclusions According to our findings, RDW was not a predictor of stent restenosis or coronary artery disease. On the other hand, our findings support the hypothesis that N/L ratio is an indicator of inflammation that plays a role in-stent restenosi