Steering hyper-giants' traffic at scale

Large content providers, known as hyper-giants, are responsible for sending the majority of the content traffic to consumers. These hyper-giants operate highly distributed infrastructures to cope with the ever-increasing demand for online content. To achieve 40 commercial-grade performance of Web applications, enhanced end-user experience, improved reliability, and scaled network capacity, hyper-giants are increasingly interconnecting with eyeball networks at multiple locations. This poses new challenges for both (1) the eyeball networks having to perform complex inbound traffic engineering, and (2) hyper-giants having to map end-user requests to appropriate servers. We report on our multi-year experience in designing, building, rolling-out, and operating the first-ever large scale system, the Flow Director, which enables automated cooperation between one of the largest eyeball networks and a leading hyper-giant. We use empirical data collected at the eyeball network to evaluate its impact over two years of operation. We find very high compliance of the hyper-giant to the Flow Director’s recommendations, resulting in (1) close to optimal user-server mapping, and (2) 15% reduction of the hyper-giant’s traffic overhead on the ISP’s long-haul links, i.e., benefits for both parties and end-users alike.EC/H2020/679158/EU/Resolving the Tussle in the Internet: Mapping, Architecture, and Policy Making/ResolutioNe

Complex analysis of energy efficiency of public buildings: case study of VGTU

The purpose of this work was to make analysis of energy efficiency of Vilnius Gediminas Technical University (VGTU) buildings. The survey was performed within the frame of the Intelligent Energy – Europe (IEE) project “Use Efficiency” – Universities and Students for Energy Efficiency.The methodology of the detailed auditing proves that energy audits must be performed with the maximum use of measurements. When having main parameters measured, it is much exact and easier to form energy balance of the building.It has been inferred that performing detailed energy audits with the support of measurements enable to asses building’s present energy efficiency very precise and consequently savings, related to the proposed energy saving measures, can be assessed more realistic than just analytical calculations.The analysis performed consists of 2 levels: the 1st and the 2nd level audits. During the 1st level audits, according to the operational energy, critical buildings were identified. The 2nd level audits contain a detailed analysis of the energy efficiency of the buildings and are based on different measurements and analytical calculations (performed according to the national methodology). This analysis could be a guideline for others performing this type of investigations

Geovisualization of Mercury Contamination in Lake St. Clair Sediments

The Laurentian Great Lakes of North America contain approximately 20% of the earth’s fresh water. Smaller lakes, rivers and channels connect the lakes to the St. Lawrence Seaway, creating an interconnected freshwater and marine ecosystem. The largest delta system in the Great Lakes is located in the northeastern portion of Lake St. Clair. This article focuses on the geovisualization of total mercury pollution from sediment samples that were collected in 1970, 1974 and 2001. To assess contamination patterns, dot maps were created and compared with surfaces that were generated using the kriging spatial interpolation technique. Bathymetry data were utilized in geovisualization procedures to develop three-dimensional representations of the contaminant surfaces. Lake St. Clair generally has higher levels of contamination in deeper parts of the lake, in the dredged shipping route through the lake and in proximity to the main outflow channels through the St. Clair delta. Mercury pollution levels were well above the Probable Effect Level in large portions of the lake in both 1970 and 1974. Lower contaminant concentrations were observed in the 2001 data. Lake-wide spatial distributions are discernable using the kriging technique; however, they are much more apparent when they are geovisualized using bathymetry data