Kilo-instruction processors: overcoming the memory wall

Historically, advances in integrated circuit technology have driven improvements in processor microarchitecture and led to todays microprocessors with sophisticated pipelines operating at very high clock frequencies. However, performance improvements achievable by high-frequency microprocessors have become seriously limited by main-memory access latencies because main-memory speeds have improved at a much slower pace than microprocessor speeds. Its crucial to deal with this performance disparity, commonly known as the memory wall, to enable future high-frequency microprocessors to achieve their performance potential. To overcome the memory wall, we propose kilo-instruction processors-superscalar processors that can maintain a thousand or more simultaneous in-flight instructions. Doing so means designing key hardware structures so that the processor can satisfy the high resource requirements without significantly decreasing processor efficiency or increasing energy consumption.Peer ReviewedPostprint (published version

Aquatic Effects of a Localized Oil Spill on Lake Conway, AR and Its Tributaries

Oil spills, no matter where they occur, elicit environmental concern and avoiding these disasters should be a priority. Old pipelines that are not regularly maintained and carry large amounts of crude oil long distances are of particular concern. One such pipeline is the 65 year-old Pegasus pipeline owned by ExxonMobil. On March 29, 2013, 795,000 L of Wabasca Heavy Canadian crude oil spilled into a neighborhood of Mayflower, Arkansas, when the Pegasus pipeline ruptured. This spill led to the evacuation of many homes in the surrounding neighborhood. Drainage ditches in the affected neighborhood drained oil into a nearby cove of Lake Conway. This lake is popular for recreational fishing, thus concerns were raised not only about the potential effects of the oil spill on area residents, but also the lake and its biological communities. Ultimately, this project assessed the effect of the oil spill in water and sediment samples on freshwater test organisms. Samples were collected at 6 sites in the affected neighborhood and in Lake Conway. Chronic Whole Effluent Toxicity (WET) tests were performed on water samples using Pimephales promelas and Ceriodaphnia dubia. Acute sediment toxicity tests were performed using Chironomus dilutus. These tests measured sub-lethal toxicity in at least one of the sampled sites, indicating that further investigation of environmental after-effects is warranted

Artificial Neural Network Model for a Low Cost Failure Sensor: Performance Assessment in Pipeline Distribution

YesThis paper describes an automated event detection and location system for water distribution pipelines which is based upon low-cost sensor technology and signature analysis by an Artificial Neural Network (ANN). The development of a low cost failure sensor which measures the opacity or cloudiness of the local water flow has been designed, developed and validated, and an ANN based system is then described which uses time series data produced by sensors to construct an empirical model for time series prediction and classification of events. These two components have been installed, tested and verified in an experimental site in a UK water distribution system. Verification of the system has been achieved from a series of simulated burst trials which have provided real data sets. It is concluded that the system has potential in water distribution network management

Programming the Navier-Stokes computer: An abstract machine model and a visual editor

The Navier-Stokes computer is a parallel computer designed to solve Computational Fluid Dynamics problems. Each processor contains several floating point units which can be configured under program control to implement a vector pipeline with several inputs and outputs. Since the development of an effective compiler for this computer appears to be very difficult, machine level programming seems necessary and support tools for this process have been studied. These support tools are organized into a graphical program editor. A programming process is described by which appropriate computations may be efficiently implemented on the Navier-Stokes computer. The graphical editor would support this programming process, verifying various programmer choices for correctness and deducing values such as pipeline delays and network configurations. Step by step details are provided and demonstrated with two example programs

Ethics and health care 'underfunding'

There are continual “crises” in health care systems worldwide as producer and patient groups unify and decry the “underfunding” of health care. Sometimes this cacophony is the self interest of profit seeking producers and often it is advocacy of unproven therapies. Such pressure is to be expected and needs careful management by explicit rationing criteria which determine who gets access to what health care. Science and rationality, however, are unfortunately, rarely the rules of conduct in the medical market-place