SUMMARYIn the near future, interconnection networks of massively parallel computer systems will connect more than a hundred thousands of computing nodes. The performance evaluation of the interconnection networks can provide real insights to help the development of efficient communication library. Hence, to evaluate the performance of such interconnection networks, simulation tools capable of modeling the networks with sufficient details, supporting a user-friendly interface to describe communication patterns, providing the users with enough performance information, completing simulations within a reasonable time, are a real necessity. This paper introduces a novel interconnection network simulator NSIM, for the evaluation of the performance of extreme-scale interconnection networks. The simulator implements a simplified simulation model so as to run faster without any loss of accuracy. Unlike the existing simulators, NSIM is built on the execution-driven simulation approach. The simulator also provides a MPI-compatible programming interface. Thus, the simulator can emulate parallel program execution and correctly simulate point-to-point and collective communications that are dynamically changed by network congestion. The experimental results in this paper showed sufficient accuracy of this simulator by comparing the simulator and the real machine. We also confirmed that the simulator is capable of evaluating ultra large-scale interconnection networks, consumes smaller memory area, and runs faster than the existing simulator. This paper also introduces a simulation service built on a cloud environment. Without installing NSIM, users can simulate interconnection networks with various configurations by using a web browser.
This paper deals with the cutting mechanism and cutting performance by ball end milling of curved surface. Firstly, the modeling of a cutter and a workpiece with a concave curved surface are carried out using 3D-CAD. Secondly, the chip area is calculated by the interference of the rake surface and the chip volume removed by a single cutting operation. The maximum chip area shows transitional phenomenon, then a new cutting method such as a looped cutter path machining is proposed and the effectiveness of the new method is considered and verified using the evaluation value which is calculated by the multiplication of the chip and the length from Z axis to the gravity of the chip area.
This paper deals with the cutting mechanism and cutting performance by ball end milling of curved surface. Firstly, the modeling of a cutter and a workpiece with a concave curved surface are carried out using 3D-CAD. Secondly, the chip area is calculated by the interference of the rake surface and the chip volume removed by a single cutting operation. The maximum chip area shows transitional phenomenon, then a new cutting method such as a looped cutter path machining is proposed and the effectiveness of the new method is considered and verified using the evaluation value which is calculated by the multiplication of the chip and the length from Z axis to the gravity of the chip area.
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