Energy-Efficient Flow Scheduling and Routing with Hard Deadlines in Data Center Networks

The power consumption of enormous network devices in data centers has emerged as a big concern to data center operators. Despite many traffic-engineering-based solutions, very little attention has been paid on performance-guaranteed energy saving schemes. In this paper, we propose a novel energy-saving model for data center networks by scheduling and routing "deadline-constrained flows" where the transmission of every flow has to be accomplished before a rigorous deadline, being the most critical requirement in production data center networks. Based on speed scaling and power-down energy saving strategies for network devices, we aim to explore the most energy efficient way of scheduling and routing flows on the network, as well as determining the transmission speed for every flow. We consider two general versions of the problem. For the version of only flow scheduling where routes of flows are pre-given, we show that it can be solved polynomially and we develop an optimal combinatorial algorithm for it. For the version of joint flow scheduling and routing, we prove that it is strongly NP-hard and cannot have a Fully Polynomial-Time Approximation Scheme (FPTAS) unless P=NP. Based on a relaxation and randomized rounding technique, we provide an efficient approximation algorithm which can guarantee a provable performance ratio with respect to a polynomial of the total number of flows.Comment: 11 pages, accepted by ICDCS'1

Partnerships for Sustainable Development Goals 2016

This present document is the fourth edition of a report that has been prepared by the Division for Sustainable Development of UN-DESA as a follow up the Rio+20 Conference in 2012, as an effort to provide status of progress multi-stakeholder partnerships and voluntary commitments have in realizing sustainable development. This current 2016 edition reviews a number of action networks and multi-stakeholder partnerships, with a particular focus on how they support the theme of the 2016 High-level Political Forum on Sustainable Development (HLPF) - "Ensuring that no one is left behind". Information in the report is largely based on submissions from the Partnerships for SDGs online platform, which was originally developed following the Rio+20 Conference in 201. The platform was recently redesigned ahead of the adoption of 2030 Agenda for Sustainable Development at the United Nations Sustainable Development Summit in September 2015

Software-Defined Cloud Computing: Architectural Elements and Open Challenges

The variety of existing cloud services creates a challenge for service providers to enforce reasonable Software Level Agreements (SLA) stating the Quality of Service (QoS) and penalties in case QoS is not achieved. To avoid such penalties at the same time that the infrastructure operates with minimum energy and resource wastage, constant monitoring and adaptation of the infrastructure is needed. We refer to Software-Defined Cloud Computing, or simply Software-Defined Clouds (SDC), as an approach for automating the process of optimal cloud configuration by extending virtualization concept to all resources in a data center. An SDC enables easy reconfiguration and adaptation of physical resources in a cloud infrastructure, to better accommodate the demand on QoS through a software that can describe and manage various aspects comprising the cloud environment. In this paper, we present an architecture for SDCs on data centers with emphasis on mobile cloud applications. We present an evaluation, showcasing the potential of SDC in two use cases-QoS-aware bandwidth allocation and bandwidth-aware, energy-efficient VM placement-and discuss the research challenges and opportunities in this emerging area.Comment: Keynote Paper, 3rd International Conference on Advances in Computing, Communications and Informatics (ICACCI 2014), September 24-27, 2014, Delhi, Indi

Cities and climate change: Strategic options for philanthropic support

Now, more than ever, cities are at the front lines of U.S. climate action. As national action stalls, there is still a daunting amount to be done in reducing human-generated climate emissions. Fortunately, this report comes in the wake of a groundswell of initiatives to engage on climate change by cities, countries, and states across the U.S. Several important and thorough reports on the types of mitigation actions cities can take have recently been released. We already have examples of cities taking significant leadership roles in reducing their own climate emissions, from New York and Boston to Austin, Boulder, and Los Angeles - yet U.S. climate emissions continue to rise, and cities have an outsized role to play. The purpose of this project is to review current U.S. city climate activities in order to identify areas where additional investment by foundations could help accelerate city action to reduce urban greenhouse gas emissions. The focus of the inquiry is on aggressive actions cities can take that significantly increase their “level of ambition” to achieve emissions reductions on an accelerated timetable. City strategies on climate adaptation are not encompassed in this project. [TRUNCATED