11827610
A Runtime System for Dynamic DAG Programming
A runtime system is described here for dynamic DAG execution. A large D A G whihc represents an application program can be executed on a parallel system without consuming large amount of memory space. A DAG scheduling algorithm has been parallelized to scale to large systems. Inaccurate estimation of task execution time and comm unication time can be tolerated. Implementation of this parallel incremental system demonstrates the feasibility of this approach. Preliminary results show that it is superior to other approaches.
28546328
Hypertool/2: A Parallel Incremental DAG Scheduling System
15212853
Core-aware memory access scheduling schemes
Multi-core processors have changed the conventional hardware structure and require a rethinking of system scheduling and resource management to utilize them efficiently. However, current multi-core systems are still using conventional single-core memory scheduling. In this study, we investigate and evaluate traditional memory access scheduling techniques, and propose a core-aware memory scheduling for multi-core environments. Since memory requests from the same source exhibit better locality, it is reasonable to schedule the requests by taking the source of the requests into consideration. Motivated from this principle of locality, we propose two core-aware policies based on traditional bank-first and row-first schemes. Simulation results show that the core-aware policies can effectively improve the performance. Compared with the bank-first and row-first policies, the proposed core-aware policies reduce the execution time of certain NAS Parallel Benchmarks by up to 20% in running the benchmarks separately, and by 11% in running them concurrently.
21338568
Research on Risk Probability Estimating Using Fuzzy Clustering for Dynamic Security Assessment
Effective network security management requires assessment of inherently uncertain events and circumstances dynamically. This paper addresses the problems of risk probability assessment and presents an alternative approach for estimating probability of security risk associated with some interaction in ubiquitous computing. A risk probability assessment formula is proposed, and an estimating model adopting the Fuzzy C-Means clustering algorithm is presented. An experiment based on DARPA intrusion detection evaluation data is given to support the suggested approach and demonstrate the feasibility and suitability for use. The practices indicate that fuzzy clustering technique provides concepts and theoretical results that are valuable in formulating and solving problems in dynamic security assessment.
9381578
Numerical complexiton solutions for the complex KdV equation by the homotopy perturbation method
In this paper, the homotopy perturbation method is extended to investigate the numerical complexiton solutions of the complex KdV equation. By constructing special forms of initial conditions, three new types of realistic numerical solutions are obtained: numerical positon solution expressed by the trigonometric functions, numerical negaton solution expressed by the hyperbolic functions and particularly the numerical analytical complexiton solutions expressed by combinations of the two kinds of functions. All these numerical solutions obtained can rapidly converge to the exact solutions obtained by Lou et al. Illustrative numerical figures are exhibited the efficiency of the proposed method.
9130265
Wireless drive and control of a swimming microrobot
A swimming microrobot actuated by two FMP (ferromagnetic polymer) fins was developed. The robot could be driven by external magnetic field wirelessly. Fabrication process and performance of the FMP actuators were presented. Working principle and scaling effect of the robot were analyzed. Experimental results demonstrated that the microrobot could swim under the water, and the speed and direction could be controlled.
5789716
Reevaluating Amdahl's law in the multicore era
Microprocessor architecture has entered the multicore era. Recently, Hill and Marty presented a pessimistic view of multicore scalability. Their analysis was based on Amdahl's law (i.e. fixed-workload condition) and challenged readers to develop better models. In this study, we analyze multicore scalability under fixed-time and memory-bound conditions and from the data access (memory wall) perspective. We use the same hardware cost model of multicore chips used by Hill and Marty, but achieve very different and more optimistic performance models. These models show that there is no inherent, immovable upper bound on the scalability of multicore architectures. These results complement existing studies and demonstrate that multicore architectures are capable of extensive scalability.