Performance Characteristics of an Intelligent Memory System

The memory system is increasingly becoming a performance bottleneck. Several intelligent memory systems, such as the ActivePages, DIVA, and IRAM architectures, have been proposed to alleviate the processor-memory bottleneck. This thesis presents the Memory Arithmetic Unit and Interface (MAUI) architecture. The MAUI architecture combines ideas of the ActivePages, DIVA, and ULMT architectures into a new intelligent memory system. A simulator of the MAUI architecture was added to the SimpleScalar v4.0 toolset. Simulation results indicate that the MAUI architecture provides the largest application speedup when operating on datasets that are much too large to fit in the processor's cache and when integrated with systems using a high performance DRAM system and a low performance processor. By coupling a 2000 MHz processor with an 800 MHz DRDRAM DRAM system, the Stream benchmark, originally written by John D. McCalpin, completed 121% faster in simulations when optimized to use the MAUI architecture

Designing a Safe, Durable, Affordable Crib

ME450 Capstone Design and Manufacturing Experience: Winter 2010Kids In DangerSM, a nonprofit organization, is concerned with safety and affordability of baby cribs currently available. This is because the crib is the one product where the child is intended to be left alone, and many low-income families with newborns cannot afford safe cribs. Ms. Nancy Cowles, Executive Director of Kids In Danger, contacted us to design and build a safe, affordable crib. Through our research, we have determined the targets needed for the design of such a crib. Using these target engineering specifications and customer requirements, we generated concept ideas in a morphological chart to meet these separate requirements. Using the concept ideas, five total crib concepts were generated and evaluated in a Pugh chart using a weighted scoring system based on the importance of the customer requirements. From this evaluation an "alpha" concept design was selected. Via engineering analysis, the alpha concept design was further refined, and the sides were made to be collapsible. These changes resulted in the final concept design. A working prototype of the final design was made and validation procedures were conducted. The mass production price was found to be $82.58, the overall weight was 45.2 lbs, and the cycles to failure were found to be 55,406. The predicted lifetime based on the cycles to failure analysis was 15.2 years, and computed with equations since there was a time constraint where an actual test could not be completed. We recommend a further refinement which would result in weight reduction as well as more rigorous safety and durability testing before widespread use.http://deepblue.lib.umich.edu/bitstream/2027.42/109380/1/me450w10project22_report.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/109380/2/me450w10project22_photo.jp

Extensions of group retractions

In this paper a condition, which is necessary and sufficient, is determined when a retraction of a subgroup H of a torsion-free group G can be extended to a retraction of G. It is also shown that each retraction of a torsion-free abelian group can be uniquely extended to a retraction of its divisible closure

Team MIT Urban Challenge Technical Report

This technical report describes Team MITs approach to theDARPA Urban Challenge. We have developed a novel strategy forusing many inexpensive sensors, mounted on the vehicle periphery,and calibrated with a new cross-­modal calibrationtechnique. Lidar, camera, and radar data streams are processedusing an innovative, locally smooth state representation thatprovides robust perception for real­ time autonomous control. Aresilient planning and control architecture has been developedfor driving in traffic, comprised of an innovative combination ofwell­proven algorithms for mission planning, situationalplanning, situational interpretation, and trajectory control. These innovations are being incorporated in two new roboticvehicles equipped for autonomous driving in urban environments,with extensive testing on a DARPA site visit course. Experimentalresults demonstrate all basic navigation and some basic trafficbehaviors, including unoccupied autonomous driving, lanefollowing using pure-­pursuit control and our local frameperception strategy, obstacle avoidance using kino-­dynamic RRTpath planning, U-­turns, and precedence evaluation amongst othercars at intersections using our situational interpreter. We areworking to extend these approaches to advanced navigation andtraffic scenarios

Three-dimensional super-resolution microscopy of the inactive X chromosome territory reveals a collapse of its active nuclear compartment harboring distinct Xist RNA foci

Background: A Xist RNA decorated Barr body is the structural hallmark of the compacted inactive X territory in female mammals. Using super resolution three-dimensional structured illumination microscopy (3D-SIM) and quantitative image analysis, we compared its ultrastructure with active chromosome territories (CTs) in human and mouse somatic cells, and explored the spatio-temporal process of Barr body formation at onset of inactivation in early differentiating mouse embryonic stem cells (ESCs). Results: We demonstrate that all CTs are composed of structurally linked chromatin domain clusters (CDCs). In active CTs the periphery of CDCs harbors low-density chromatin enriched with transcriptionally competent markers, called the perichromatin region (PR). The PR borders on a contiguous channel system, the interchromatin compartment (IC), which starts at nuclear pores and pervades CTs. We propose that the PR and macromolecular complexes in IC channels together form the transcriptionally permissive active nuclear compartment (ANC). The Barr body differs from active CTs by a partially collapsed ANC with CDCs coming significantly closer together, although a rudimentary IC channel system connected to nuclear pores is maintained. Distinct Xist RNA foci, closely adjacent to the nuclear matrix scaffold attachment factor-A (SAF-A) localize throughout Xi along the rudimentary ANC. In early differentiating ESCs initial Xist RNA spreading precedes Barr body formation, which occurs concurrent with the subsequent exclusion of RNA polymerase II (RNAP II). Induction of a transgenic autosomal Xist RNA in a male ESC triggers the formation of an `autosomal Barr body' with less compacted chromatin and incomplete RNAP II exclusion. Conclusions: 3D-SIM provides experimental evidence for profound differences between the functional architecture of transcriptionally active CTs and the Barr body. Basic structural features of CT organization such as CDCs and IC channels are however still recognized, arguing against a uniform compaction of the Barr body at the nucleosome level. The localization of distinct Xist RNA foci at boundaries of the rudimentary ANC may be considered as snap-shots of a dynamic interaction with silenced genes. Enrichment of SAF-A within Xi territories and its close spatial association with Xist RNA suggests their cooperative function for structural organization of Xi

Energy Resolution Performance of the CMS Electromagnetic Calorimeter

The energy resolution performance of the CMS lead tungstate crystal electromagnetic calorimeter is presented. Measurements were made with an electron beam using a fully equipped supermodule of the calorimeter barrel. Results are given both for electrons incident on the centre of crystals and for electrons distributed uniformly over the calorimeter surface. The electron energy is reconstructed in matrices of 3 times 3 or 5 times 5 crystals centred on the crystal containing the maximum energy. Corrections for variations in the shower containment are applied in the case of uniform incidence. The resolution measured is consistent with the design goals

Preparation of Pretreated Biomass

This report describes the development of the wet-explosion pretreatment technology on Douglas-fir forest residuals