• Title/Summary/Keyword: Simpy

Search Result 6, Processing Time 0.022 seconds

Dynamic Channel Allocation Control with thresholds in Wireless Cellular Networks using Simpy

  • Cao, Yang;Ro, Cheul-Woo
    • International Journal of Contents
    • /
    • v.8 no.2
    • /
    • pp.19-22
    • /
    • 2012
  • New and handoff calls control mechanisms are the key point to wireless cellular networks. In this paper, we present an adaptive algorithm for dynamic channel allocation scheme with guard channels and also with handoff calls waiting queue ensuring that handoff calls take priority over new calls. Our goal is to find better tradeoff between handoffs and new calls blocking probabilities in order to achieve more efficient channel utilization. Simpy is a Python based discrete event simulation system. We use Simpy to build our simulation models to get analytical data.

Performance Analysis of Virtual Storage

  • Wei, X;RO, CheulWoo
    • Proceedings of the Korea Contents Association Conference
    • /
    • 2018.05a
    • /
    • pp.511-512
    • /
    • 2018
  • Virtual machine technology enables multiple hosts to share the same LUN(Logical Unit Number) and the same storage, but if too many hosts share the same LUN, it will increase the delay. In this paper we propose a performance model, get several values of scalable storage performance in virtual environment, and present the results examined the effects of I/O queuing in a virtual infrastructure. This results show how to make the most effective use of our storage resources.

  • PDF

A Brief Study on the Fabrication of III-V/Si Based Tandem Solar Cells

  • Panchanan, Swagata;Dutta, Subhajit;Mallem, Kumar;Sanyal, Simpy;Park, Jinjoo;Ju, Minkyu;Cho, Young Hyun;Cho, Eun-Chel;Yi, Junsin
    • Current Photovoltaic Research
    • /
    • v.6 no.4
    • /
    • pp.109-118
    • /
    • 2018
  • Silicon (Si) solar cells are the most successful technology which are ruling the present photovoltaic (PV) market. In that essence, multijunction (MJ) solar cells provided a new path to improve the state-of-art efficiencies. There are so many hurdles to grow the MJ III-V materials on Si substrate as Si with other materials often demands similar qualities, so it is needed to realize the prospective of Si tandem solar cells. However, Si tandem solar cells with MJ III-V materials have shown the maximum efficiency of 30 %. This work reviews the development of the III-V/Si solar cells with the synopsis of various growth mechanisms i.e hetero-epitaxy, wafer bonding and mechanical stacking of III-V materials on Si substrate. Theoretical approaches to design efficient tandem cell with an analysis of state-of-art silicon solar cells, sensitivity, difficulties and their probable solutions are discussed in this work. An analytical model which yields the practical efficiency values to design the high efficiency III-V/Si solar cells is described briefly.

Finite Element Analysis for the Optimal Shape of the High Voltage Insulator for Power Transmission Lines (송전선로용 고전압 절연체의 최적 형상에 대한 유한요소 해석)

  • Kim, Taeyong;Sanyal, Simpy;Rabelo, Matheus;Yi, Junsin
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.35 no.1
    • /
    • pp.66-71
    • /
    • 2022
  • The insulator used for the transmission line is a device that is bonded with a cap, pin, ceramic, and cement to withstand insulation capacity and mechanical load. The insulator design can help to reduce the dispersion of the electric field; thus, the optimization of today's design, especially as demanded power grows, is critical. The designs of four manufacturers were used to perform a comparative analysis. Under dry circumstances of the new product, an electric field distribution study was done with no pollutants attached. Manufacturer D's design has the best voltage uniformity of 24.33% and the arc length of 500 mm or more. Manufacturer C's design has an equalizing voltage of more than 2% higher than that of other manufacturers. The importance of the design of the insulator and the number of connections according to the installation conditions is very efficient for transmission lines that will increase in the future.

Hole Selective Contacts: A Brief Overview

  • Sanyal, Simpy;Dutta, Subhajit;Ju, Minkyu;Mallem, Kumar;Panchanan, Swagata;Cho, Eun-chel;Cho, Young Hyun;Yi, Junsin
    • Current Photovoltaic Research
    • /
    • v.7 no.1
    • /
    • pp.9-14
    • /
    • 2019
  • Carrier selective solar cell structure has allured curiosity of photovoltaic researchers due to the use of wide band gap transition metal oxide (TMO). Distinctive p/n-type character, broad range of work functions (2 to 7 eV) and risk free fabrication of TMO has evolved new concept of heterojunction intrinsic thin layer (HIT) solar cell employing carrier selective layers such as $MoO_x$, $WO_x$, $V_2O_5$ and $TiO_2$ replacing the doped a-Si layers on either front side or back side. The p/n-doped hydrogenated amorphous silicon (a-Si:H) layers are deposited by Plasma-Enhanced Chemical Vapor Deposition (PECVD), which includes the flammable and toxic boron/phosphorous gas precursors. Due to this, carrier selective TMO is gaining popularity as analternative risk-free material in place of conventional a-Si:H. In this work hole selective materials such as $MoO_x$, $WO_x$ and $V_2O_5$has been investigated. Recently $MoO_x$, $WO_x$ & $V_2O_5$ hetero-structures showed conversion efficiency of 22.5%, 12.6% & 15.7% respectively at temperature below $200^{\circ}C$. In this work a concise review on few important aspects of the hole selective material solar cell such as historical developments, device structure, fabrication, factors effecting cell performance and dependency on temperature has been reported.

Improvement of Storage Performance by HfO2/Al2O3 Stacks as Charge Trapping Layer for Flash Memory- A Brief Review

  • Fucheng Wang;Simpy Sanyal;Jiwon Choi;Jaewoong Cho;Yifan Hu;Xinyi Fan;Suresh Kumar Dhungel;Junsin Yi
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.36 no.3
    • /
    • pp.226-232
    • /
    • 2023
  • As a potential alternative to flash memory, HfO2/Al2O3 stacks appear to be a viable option as charge capture layers in charge trapping memories. The paper undertakes a review of HfO2/Al2O3 stacks as charge trapping layers, with a focus on comparing the number, thickness, and post-deposition heat treatment and γ-ray and white x-ray treatment of such stacks. Compared to a single HfO2 layer, the memory window of the 5-layered stack increased by 152.4% after O2 annealing at ±12 V. The memory window enlarged with the increase in number of layers in the stack and the increase in the Al/Hf content in the stack. Furthermore, our comparison of the treatment of HfO2/Al2O3 stacks with varying annealing temperatures revealed that an increased annealing temperature resulted in a wider storage window. The samples treated with O2 and subjected to various γ radiation intensities displayed superior resistance. and the memory window increased to 12.6 V at ±16 V for 100 kGy radiation intensity compared to the untreated samples. It has also been established that increasing doses of white x-rays induced a greater number of deep defects. The optimization of stacking layers along with post-deposition treatment condition can play significant role in extending the memory window.