scholarly journals Designing an Optimal Lightning Protection Scheme for Substations Using Shielding Wires

2017 ◽  
Vol 7 (3) ◽  
pp. 1595-1599 ◽  
Author(s):  
A. Khodadadi ◽  
M. H. Nazari ◽  
S. H. Hosseinian

An optimal lightning protection scheme for a substation using shielding wires is investigated in this paper through computer software analysis. An economic approach is utilized by choosing a reasonable trade-off between protection, the number of shielding wires and the heights of them from the ground. This study is initially applied to a simple two-wire system and then extended to a sample substation. The solution for each problem is executed in MATLAB and 3-D realization is shown.

Author(s):  
Amir Mahdi Hosseini Monazzah ◽  
Amir M. Rahmani ◽  
Antonio Miele ◽  
Nikil Dutt

AbstractDue to the consistent pressing quest of larger on-chip memories and caches of multicore and manycore architectures, Spin Transfer Torque Magnetic RAM (STT-MRAM or STT-RAM) has been proposed as a promising technology to replace classical SRAMs in near-future devices. Main advantages of STT-RAMs are a considerably higher transistor density and a negligible leakage power compared with SRAM technology. However, the drawback of this technology is the high probability of errors occurring especially in write operations. Such errors are asymmetric and transition-dependent, where 0 → 1 is the most critical one, and is high subjected to the amount and current (voltage) supplied to the memory during the write operation. As a consequence, STT-RAMs present an intrinsic trade-off between energy consumption vs. reliability that needs to be properly tuned w.r.t. the currently running application and its reliability requirement. This chapter proposes FlexRel, an energy-aware reliability improvement architectural scheme for STT-RAM cache memories. FlexRel considers a memory architecture provided with Error Correction Codes (ECCs) and a custom current regulator for the various cache ways and conducts a trade-off between reliability and energy consumption. FlexRel cache controller dynamically profiles the number of 0 → 1 transitions of each individual bit write operation in a cache block and based on that selects the most-suitable cache way and current level to guarantee the necessary error rate threshold (in terms of occurred write errors) while minimizing the energy consumption. We experimentally evaluated the efficiency of FlexRel against the most efficient uniform protection scheme from reliability, energy, area, and performance perspectives. Experimental simulations performed by using gem5 has demonstrated that while FlexRel satisfies the given error rate threshold, it delivers up to 13.2% energy saving. From the area footprint perspective, FlexRel delivers up to 7.9% cache ways’ area saving. Furthermore, the performance overhead of the FlexRel algorithm which changes the traffic patterns of the cache ways during the executions is 1.7%, on average.


Author(s):  
Untung Ismoyo ◽  
Boedi Hendrarto ◽  
Suryanti Suryanti

ABSTRAK Bakau (Rhizopora mucronata) merupakan salah satu jenis mangrove yang terdapat pada kawasan rehabilitasi hutan mangrove Desa Mojo, Kabupaten Pemalang.Jenis mangrove ini ditanam karena bibitnya mudah diperoleh dan disemai sehingga mendominasi pada kawasan tersebut.Untuk mengetahui faktor-faktor yang berkaitan dengan pertumbuhan mangrove, maka telah dilakukanpenelitian tentang hubungan antara kualitas tanahdengan luasan helai daun mangrove.Jumlah sampel yang digunakan adalah405helai daun yang dipilih dengan kondisi yang sama dan berasal dari 9 stasiun penelitian. Dalam stasion yangsama dilakukan pula pengambilan sampel tanah sampai kedalaman 50 cm, untuk dianalisis kandungan bahan organik dan sifat fisik-kimia.  Sampel daun yang diperoleh kemudian diproses dalam photo studio mini buatan untuk diambil gambarnya menggunakan kamera digital beresolusi tinggi dalam jarak 30 cm dan dihitung luasannya denganperangkat lunak komputer Corel Draw X7.Analisis data menggunakan PCA dan hasilnya menunjukkan, bahwa dari semua variabel yang diukur dari tanah, maka hanya faktorbahan organik saja yang memiliki korelasi positif tinggi dengan luasan daunR. mucronata. Kata kunci: Pohon Bakau, Luasan Daun, Hutan Mangrove Desa Mojo ABSTRACT Mangrove (Rhizopora mucronata) is one of the mangrove species found in the rehabilitation area of mangrove forest of Mojo Village, Pemalang Regency. This type of mangrove is grown because the seeds are easy to obtain and sowing so as to dominate in the area. To know the factors related to the growth of mangroves, so has been conducted research on the relationship between soil quality with the extent of mangrove leaves. The number of samples used is 405 leaf blades selected under the same conditions and derived from 9 research stations. In the same station, soil sampling is done up to 50 cm depth, to analyze organic material content and physical-chemical properties. The leaf samples were then processed in an artificial mini studio photo to be photographed using a high resolution digital camera within 30 cm and calculated the extent of Corel Draw X7 computer software. Analysis of data using PCA and the results show, that of all variables measured from the soil, then only the factor of organic material alone has a high positive correlation with the leaf area of R. mucronata. Keywords: Mangrove, Leaf Extents, Mojo Village’s Mangrove Forest 


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