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Articles 1 - 11 of 11
Full-Text Articles in Physical Sciences and Mathematics
Data Transport System, Rahav Dor
Data Transport System, Rahav Dor
All Computer Science and Engineering Research
To facilitate the WU Smart Home research [21] we built a system that collects data from sensors and uploads the data to the cloud. The system supports data collection from multiple locations (typically apartments) that are independent from each other, endowing the system with two benefit: distributed data collection and alleviating privacy concerns. Each location is managed by a local micro-server (μServer) that is responsible for receiving data packets from sensors and managing their transient storage. Periodically the μServer triggers a data transport process that moves the data to a cloud server where it is stored in a centralized database. …
Exploring User-Provided Connectivity, Mohammad H. Afrasiabi, Roch Guerin
Exploring User-Provided Connectivity, Mohammad H. Afrasiabi, Roch Guerin
All Computer Science and Engineering Research
Network services often exhibit positive and negative externalities that affect users' adoption decisions. One such service is "user-provided connectivity" or UPC. The service offers an alternative to traditional infrastructure-based communication services by allowing users to share their "home base" connectivity with other users, thereby increasing their access to connectivity. More users mean more connectivity alternatives, i.e., a positive externality, but also greater odds of having to share one's own connectivity, i.e., a negative externality. The tug of war between positive and negative externalities together with the fact that they often depend not just on how many but also which users …
Migrating To Ipv6 - The Role Of Basic Coordination, Mehdi Nikkhah, Roch Guerin
Migrating To Ipv6 - The Role Of Basic Coordination, Mehdi Nikkhah, Roch Guerin
All Computer Science and Engineering Research
The need for a larger Internet address space was acknowledged early on, and a solution (IPv6) standardized years ago. Its adoption has, however, been anything but easy and still faces significant challenges. The situation begs the questions of "why has it been so difficult?" and "what could have been (or still be) done to facilitate this migration?" There has been significant recent interest in those questions, and the paper builds on a line of work based on technology adoption models to explore them. The results confirm the impact of several known factors, but also provide new insight. In particular, they …
Global Edf Scheduling For Parallel Real-Time Tasks, Jing Li
Global Edf Scheduling For Parallel Real-Time Tasks, Jing Li
McKelvey School of Engineering Theses & Dissertations
As multicore processors become ever more prevalent, it is important for real-time programs to take advantage of intra-task parallelism in order to support computation-intensive applications with tight deadlines. In this thesis, we consider the Global Earliest Deadline First (GEDF) scheduling policy for task sets consisting of parallel tasks. Each task can be represented by a directed acyclic graph (DAG) where nodes represent computational work and edges represent dependences between nodes. In this model, we prove that GEDF provides a capacity augmentation bound of 4-2/m and a resource augmentation bound of 2-1/m. The capacity augmentation bound acts as a linear-time schedulability …
Capacity Augmentation Bound Of Federated Scheduling For Parallel Dag Tasks, Jing Li, Abusayeed Saifullah, Kunal Agrawal, Christopher Gill
Capacity Augmentation Bound Of Federated Scheduling For Parallel Dag Tasks, Jing Li, Abusayeed Saifullah, Kunal Agrawal, Christopher Gill
All Computer Science and Engineering Research
We present a novel federated scheduling approach for parallel real-time tasks under a general directed acyclic graph (DAG) model. We provide a capacity augmentation bound of 2 for hard real-time scheduling; here we use the worst-case execution time and critical-path length of tasks to determine schedulability. This is the best known capacity augmentation bound for parallel tasks. By constructing example task sets, we further show that the lower bound on capacity augmentation of federated scheduling is also 2 for any m > 2. Hence, the gap is closed and bound 2 is a strict bound for federated scheduling. The federated scheduling …
Federated Scheduling For Stochastic Parallel Real-Time Tasks, Jing Li, Kunal Agrawal, Christopher Gill, Chenyang Lu
Federated Scheduling For Stochastic Parallel Real-Time Tasks, Jing Li, Kunal Agrawal, Christopher Gill, Chenyang Lu
All Computer Science and Engineering Research
Federated scheduling is a strategy to schedule parallel real-time tasks: It allocates a dedicated cluster of cores to high-utilization task (utilization >1); It uses a multiprocessor scheduling algorithm to schedule and execute all low-utilization tasks sequentially, on a shared cluster of the remaining cores. Prior work has shown that federated scheduling has the best known capacity augmentation bound of 2 for parallel tasks with implicit deadlines. In this paper, we explore the soft real-time performance of federated scheduling and address the average-case workloads instead of the worst-case values. In particular, we consider stochastic tasks -- tasks for which execution time …
Rt-Openstack: A Real-Time Cloud Management System, Sisu Xi, Chong Li, Chenyang Lu, Christopher D. Gill, Meng Xu, Linh T.X. Phan, Insup Lee, Oleg Sokolsky
Rt-Openstack: A Real-Time Cloud Management System, Sisu Xi, Chong Li, Chenyang Lu, Christopher D. Gill, Meng Xu, Linh T.X. Phan, Insup Lee, Oleg Sokolsky
All Computer Science and Engineering Research
Clouds have become appealing platforms for running not only general-purpose applications but also real-time applications. However, current clouds cannot provide real-time performance for virtual machines (VM) for two reasons: (1) the lack of a real-time virtual machine monitor (VMM) scheduler on a single host, and (2) the lack of a real-time aware VM placement scheme by the cloud manager. While real-time VM schedulers do exist, prior solutions employ either heuristics-based approaches that cannot always achieve predictable latency or apply real-time scheduling theory that may result in low CPU utilization. We observe the demand and advantage for co-hosting real-time (RT) VMs …
Cloudpowercap: Integrating Power Budget And Resource Management Across A Virtualized Server Cluster, Yong Fu, Anne Holler, Chenyang Lu
Cloudpowercap: Integrating Power Budget And Resource Management Across A Virtualized Server Cluster, Yong Fu, Anne Holler, Chenyang Lu
All Computer Science and Engineering Research
In many datacenters, server racks are highly underutilized. Rack slots are left empty to keep the sum of the server nameplate maximum power below the power provisioned to the rack. And the servers that are placed in the rack cannot make full use of available rack power. The root cause of this rack underutilization is that the server nameplate power is often much higher than can be reached in practice. To address rack underutilization, server vendors are shipping support for per-host power caps, which provide a server-enforced limit on the amount of power that the server can draw. Using this …
Performance Modeling Of Virtualized Custom Logic Computations, Michael J. Hall, Roger D. Chamberlain
Performance Modeling Of Virtualized Custom Logic Computations, Michael J. Hall, Roger D. Chamberlain
All Computer Science and Engineering Research
Virtualization of custom logic computations (i.e., by sharing a fixed function across distinct data streams) provides a means of reusing hardware resources, particularly when resources are limited. This is common practice in traditional processors where more than one user can share processor resources. In this paper, we virtualize a custom logic block using C-slow techniques to support fine-grain context-switching. We then develop and present an analytic model for several performance measures (throughput, latency, input queue occupancy) for both fine-grained and coarse-grained context switching (to a secondary memory). Next, we calibrate the analytic performance model with empirical measurements. We then validate …
Inferring Memory Map Instructions, Paul T. Scheid, Ari J. Spilo, Ron K. Cytron
Inferring Memory Map Instructions, Paul T. Scheid, Ari J. Spilo, Ron K. Cytron
All Computer Science and Engineering Research
We describe the problem of inferring a set of memory map instructions from a reference trace, with the goal of minimizing the number of such instructions as well as the number of unreferenced but mapped storage locations. We prove the related decision problem NP-complete. We then present and compare the results of two heuristic approaches on some actual traces.
Streaming Computations With Precise Control, Peng Li, Kunal Agrawal, Jeremy Buhler, Roger Chamberlain
Streaming Computations With Precise Control, Peng Li, Kunal Agrawal, Jeremy Buhler, Roger Chamberlain
All Computer Science and Engineering Research
No abstract provided.