Joint Data compression and Computation offloading in Hierarchical Fog-Cloud Systems

Data compression has the potential to significantly improve the computation offloading performance in hierarchical fog-cloud systems. However, it remains unknown how to optimally determine the compression ratio jointly with the computation offloading decisions and the resource allocation. This joint optimization problem is studied in the current paper where we aim to minimize the maximum weighted energy and service delay cost (WEDC) of all users. First, we consider a scenario where data compression is performed only at the mobile users. We prove that the optimal offloading decisions have a threshold structure. Moreover, a novel three-step approach employing convexification techniques is developed to optimize the compression ratios and the resource allocation. Then, we address the more general design where data compression is performed at both the mobile users and the fog server. We propose three efficient algorithms to overcome the strong coupling between the offloading decisions and resource allocation. We show that the proposed optimal algorithm for data compression at only the mobile users can reduce the WEDC by a few hundred percent compared to computation offloading strategies that do not leverage data compression or use sub-optimal optimization approaches. Besides, the proposed algorithms for additional data compression at the fog server can further reduce the WEDC

Breaking the Buildup-time Limit of sensitivity in Avalanche Photodiodes by Dynamic Biasing

Avalanche photodiodes (APDs) are the preferred photodetectors for direct-detection, high data-rate long-haul optical telecommunications. APDs can detect low-level optical signals due to their internal amplification of the photon-generated electrical current, which is attributable to the avalanche of electron and hole impact ionizations. Despite recent advances in APDs aimed at reducing the average avalanche-buildup time, which causes intersymbol interference and compromises receiver sensitivity at high data rates, operable speeds of commercially available APDs have been limited to 10Gbps. We report the first demonstration of a dynamically biased APD that breaks the traditional sensitivity-versus-speed limit by employing a data-synchronous sinusoidal reverse-bias that drastically suppresses the average avalanche-buildup time. Compared with traditional DC biasing, the sensitivity of germanium APDs at 3Gbps is improved by 4.3 dB, which is equivalent to a 3,500-fold reduction in the bit-error rate. The method is APD-type agnostic and it promises to enable operation at rates of 25Gbps and beyond

KinectVision360: A Real-time Human Tracking System

KinectVision360 project integrates multiple Microsoft Kinect sensors to investigate the capabilities of the low cost human interactive device to apply them to modern problems in comparison to high cost devices. The project includes human face/skeletal tracking and a larger field of vision. We incorporate three Kinects (1st generation) and a custom computer with components necessary to process large amounts of data in real-time. Figure 1 represents an overview of the processes the program follows in order to execute and visualize the data for tracking. The “FaceTracking” class contains algorithms and logic to retrieve skeletal information from infrared depth sensors in the API. In a two-stage process, body position is understood by calculating a depth-map with structured light and then infers the body position using machine learning. Microsoft trained the system with over a million samples using a random decision forest. We enhance the tracking by rejecting poor construction of skeletons or faces. The class also transfers data between the sensors to allow for communication. We are restricted in how much data we can process due to hardware limitations. We compensate for complexity of code and computer performance which we overcome by limiting ourselves to 3 sensors. Overall, the system can analyze realtime data and visualize the data as it is being recorded with multiple integrated sensors.https://scholarscompass.vcu.edu/capstone/1112/thumbnail.jp

Rural Roads: Multi-Tier Monitoring of Infrastructure: Top Down and Bottom Up

The focus of this paper is on the last set of these questions -- that of the capacity and the practice of decentralized infrastructure monitoring. The experience and practice of low, middle and high income countries alike is considered. The paper is organized as follows: the next section, Section 2, defines how infrastructure is defined for purposes here, and then proceeds to discuss where the monitoring of infrastructure fits into the broader activity of decentralized infrastructure management. Section 3 then lays out some of the “pre-conditions” for effective decentralized monitoring of infrastructure, leading to the conclusion that for many developing countries these pre-conditions are not satisfied and, thus, why in order to make useful statements about decentralized monitoring of infrastructure one turns to specific case studies for lessons learned from current practice. Accordingly, Section 4 focuses on a mix of illustrative country practices on governmental monitoring of infrastructure that serve to reinforce the conventional view that though there are core lessons common to all intergovernmental societies, there is no single “best” approach since each country faces different starting and end points to which they aspire. Section 5 reviews selected non-governmental and civil society role in what the paper labels as decentralized “bottom up” monitoring. Concluding comments are provided in Section 6

Working Futures 2017-2027 : Long-run labour market and skills projections headline report

This report provides a concise overview of Working Futures 2017-2027 results for the UK. It presents historical trends and future prospects by sector for the UK and its constituent nations and the English regions. The prime focus of Working Futures is on the demand for skills as measured by employment by occupation and qualification, although the supply side is also considered. Its prime objective is to provide useful labour market information that can help to inform policy development and strategy around skills, careers and employment, for both policy makers and a much wider audience. The results are intended to provide a sound statistical foundation for reflection and debate among all those with an interest in the demand for and supply of skills. It is aimed at the general reader and focuses on the key messages from this very detailed study. It complements the more detailed outputs and results from the project available from the gov.uk website2 and cover sectors, occupations, geography and qualifications

Saturation bounds for smooth varieties

We prove bounds on the saturation degrees of homogeneous ideals (and their powers) defining smooth complex projective varieties. For example, we show that a classical statement due to Macualay for zero-dimensional complete intersection ideals holds for any smooth variety. For curves, we bound the saturation degree of powers in terms of the regularity