International Journal of Natural Sciences Research

Published by: Conscientia Beam
Online ISSN: 2311-4746
Print ISSN: 2311-7435
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No. 6

Structural Design of A Linear-Motion Type Semi-Active Damper by Finite Element Method

Pages: 107-111
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Structural Design of A Linear-Motion Type Semi-Active Damper by Finite Element Method

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DOI: 10.18488/journal.63/2016.4.6/63.6.107.111

Citation: 1

Takahito ADACHI , Kenji TAKAHARA

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Takahito ADACHI , Kenji TAKAHARA (2016). Structural Design of A Linear-Motion Type Semi-Active Damper by Finite Element Method. International Journal of Natural Sciences Research, 4(6): 107-111. DOI: 10.18488/journal.63/2016.4.6/63.6.107.111
The purpose of this study is to design a structure of a linear-motion type semi-active damper which can reduce the vibration caused by an earthquake. This paper proposes the more effective structure of the linear motion semi-active damper by magnetic-structure interaction analysis of finite element method using ANSYS. The semi-active damper has a simple structure that a linear mover, a magnet bar, reciprocates in coils of a stator. The size of the coils and the size of the magnetic material cover which can produce the maximum damping force are simulated under the condition that the size of the mover is fixed. The electromotive force is calculated based on the change of the produced magnetic field according to the change of the given velocity of the mover in a short time. The damping force is calculated according to the electric current which the electromotive force supplies to the connected resistance. By the simulations, more than 120 [N s/m] of the maximum damping coefficient is acquired in the case that the coil is wound up from 28.0[mm] of the inner diameter to 60.0 [mm] of the outer diameter.
Contribution/ Originality

Improving Cloud System Performances by Adopting Nvram-Based Storage Systems

Pages: 100-106
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Improving Cloud System Performances by Adopting Nvram-Based Storage Systems

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DOI: 10.18488/journal.63/2016.4.6/63.6.100.106

Jisun Kim , Yunjoo Park , Sunhwa A. Nam , Hyunkyoung Choi , KyungWoon Cho , Hyokyung Bahn

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Jisun Kim , Yunjoo Park , Sunhwa A. Nam , Hyunkyoung Choi , KyungWoon Cho , Hyokyung Bahn (2016). Improving Cloud System Performances by Adopting Nvram-Based Storage Systems. International Journal of Natural Sciences Research, 4(6): 100-106. DOI: 10.18488/journal.63/2016.4.6/63.6.100.106
NVRAM is being considered as an additional memory/storage component of future cloud computing systems. This paper investigates how much performance improvement can be obtained if we add NVRAM as the memory/storage media of cloud systems. As NVRAM is put on DDR slots, it is byte-accessible and hence can be used as a memory medium like DRAM. It can also be utilized as swap or journal devices if we use it as a block I/O device. We first consider NVRAM as a storage cache, and then, we measure the performance of systems that additionally use NVRAM as memory, swap, and journal devices. We use two workloads, I/O and memory intensive workloads. Our experiments show that using NVRAM as a journal device performs the best in I/O-intensive workload as it performs journaling I/O on NVRAM instead of slow storage. Using NVRAM as memory or swap devices does not show good results in I/O-intensive workload. However, in case of memory-intensive workload, NVRAM memory significantly improves the performance, and NVRAM swap also gains a certain level of improvement. We expect that our experiments will be helpful in the design of NVRAM-based cloud systems for memory or I/O intensive workload situations.
Contribution/ Originality
The paper’s primary contribution is finding the NVRAM’s effectiveness on the performance of future cloud systems. Specifically, we show the effectiveness of NVRAM if it is used as storage cache, main memory, journal device, or swap device in the memory hierarchy of cloud computing systems.