101 research outputs found

    Application-Level Performance Improvement for Stream Program on CGRA-based systems

    Get PDF
    Department of Computer EngineeringCoarse-Grained Reconfigurable Architectures (CGRAs), often used as coprocessors for DSP and multimedia kernels, can deliver highly energy-effcient execution for compute-intensive kernels. Simultaneously, stream applications, which consist of many actors and channels connecting them, can provide natural representations for DSP applications, and therefore be a good match for CGRAs. We present our results of mapping DSP applications written in StreamIt language to CGRAs, along with our mapping flow. One important challenge in mapping is how to manage the multitude of kernels in the application for the limited local memory of a CGRA, for which we present a novel integer linear programming-based solution. Our evaluation results demonstrate that our software and hardware optimizations can help generate highly effcient mapping of stream applications to CGRAs, enabling far more energy-effcient executions (7x worse to 50x better) compared to using state-of-theart GP-GPUs. Further, we eliminate communication overhead and reduce computation overhead using combination of sychronous/asynchronous processors and DMA. This optimization also improve performance by 17.1% on average comparing to baseline system.ope

    Development of Soil Compaction Analysis Software (SCAN) Integrating a Low Cost GPS Receiver and Compactometer

    Get PDF
    A software for soil compaction analysis (SCAN) has been developed for evaluating the compaction states using the data from the GPS as well as a compactometer attached on the roller. The SCAN is distinguished from other previous software for intelligent compaction (IC) in that it can use the results from various types of GPS positioning methods, and it also has an optimal structure for remotely managing the large amounts of data gathered from numerous rollers. For this, several methods were developed: (1) improving the accuracy of low cost GPS receiver’s positioning results; (2) modeling the trajectory of a moving roller using a GPS receiver’s results and linking it with the data from the compactometer; and (3) extracting the information regarding the compaction states of the ground from the modeled trajectory, using spatial analysis methods. The SCAN was verified throughout various field compaction tests, and it has been confirmed that it can be a very effective tool in evaluating field compaction states

    Change of Femoral Anteversion Angle in Children With Intoeing Gait Measured by Three-Dimensional Computed Tomography Reconstruction: One-Year Follow-Up Study

    Get PDF
    ObjectiveTo evaluate femoral anteversion angle (FAA) change in children with intoeing gait depending on age, gender, and initial FAA using three-dimensional computed tomography (3D-CT).MethodsThe 3D-CT data acquired between 2006 and 2016 were retrospectively reviewed. Children 4 to 10 years of age with symptomatic intoeing gait with follow-up interval of at least 1 year without active treatment were enrolled. Subjects were divided into three groups based on age: group 1 (≥4 and <6 years), group 2 (≥6 and <8 years), and group 3 (≥8 and <10 years). Initial and follow-up FAAs were measured using 3D-CT. Mean changes in FAAs were calculated and compared.ResultsA total of 200 lower limbs of 100 children (48 males and 52 females, mean age of 6.1±1.6 years) were included. The mean follow-up period was 18.0±5.4 months. Average initial and follow-up FAA in children with intoeing gait was 31.1°±7.8° and 28.9°±8.2°, respectively. The initial FAA of group 1 was largest (33.5°±7.7°). Follow-up FAA of group 1 was significantly reduced to 28.7°±9.2° (p=0.000). FAA changes in groups 1, 2, and 3 were −6.5°±5.8°, −6.4°±5.1°, and −5.3°±4.0°, respectively. These changes of FAA were not significantly (p=0.355) different among the three age groups. However, FAA changes were higher (p=0.012) in females than those in males. In addition, FAA changes showed difference depending on initial FAA. When initial FAA was smaller than 30°, mean FAA change was −5.6°±4.9°. When initial FAA was more than 30°, mean FAA change was −6.8°±5.4° (p=0.019).ConclusionFAA initial in children with intoeing gait was the greatest in age group 1 (4–6 years). This group also showed significant FAA decrease at follow-up. FAA changes were greater when the child was a female, younger, and had greater initial FAA

    Unveiling the carrier transport mechanism in epitaxial graphene for forming wafer-scale, single-domain graphene

    Get PDF
    Graphene epitaxy on the Si face of a SiC wafer offers monolayer graphene with unique crystal orientation at the wafer-scale. However, due to carrier scattering near vicinal steps and excess bilayer stripes, the size of electrically uniform domains is limited to the width of the terraces extending up to a few microns. Nevertheless, the origin of carrier scattering at the SiC vicinal steps has not been clarified so far. A layer-resolved graphene transfer (LRGT) technique enables exfoliation of the epitaxial graphene formed on SiC wafers and transfer to flat Si wafers, which prepares crystallographically single-crystalline monolayer graphene. Because the LRGT flattens the deformed graphene at the terrace edges and permits an access to the graphene formed at the side wall of vicinal steps, components that affect the mobility of graphene formed near the vicinal steps of SiC could be individually investigated. Here, we reveal that the graphene formed at the side walls of step edges is pristine, and scattering near the steps is mainly attributed by the deformation of graphene at step edges of vicinalized SiC while partially from stripes of bilayer graphene. This study suggests that the two-step LRGT can prepare electrically single-domain graphene at the wafer-scale by removing the major possible sources of electrical degradation

    OF@TEIN: An OpenFlow-enabled SDN Testbed over International SmartX Rack Sites

    Get PDF
    In this paper, we will discuss our on-going effort for OF@TEIN SDN(Software-Defined Networking) testbed, which currently spans over Korea and fiveSouth-East Asian (SEA) collaborators with internationally deployed OpenFlowenabledSmartX Racks

    Expansion strategies of South Korean multinationals

    No full text

    Efficient Execution of Stream Graphs on Coarse-Grained Reconfigurable Architectures

    No full text
    Coarse-grained reconfigurable architectures (CGRAs) can provide extremely energy-efficient acceleration for applications that are rich in arithmetic operations such as digital signal processing and multimedia applications. Since those applications are often naturally represented by stream graphs, it is very compelling to develop optimization strategies for stream graphs on CGRAs. One unique property of stream graphs is that they contain many kernels or loops, which creates both advantages and challenges when it comes to mapping them to CGRAs. This paper addresses two main problems with it, namely, many-buffer problem and control overhead problem, and presents our results of optimizing the execution of stream graphs for CGRAs including our low-cost architecture extensions. Our evaluation results demonstrate that our software and hardware optimizations can help generate highly efficient mapping of stream applications to CGRAs, with 3.4x speedup on average at the application level over CPU-only execution, which is significant
    corecore