• Title/Summary/Keyword: Fiber path

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A New Techno-Economic Modeling and Analysis for FTTH Optical Access Networks (광 가입자 망 진화를 위한 기술 경제성 평가)

  • Lee, Young-Ho;Hahm, Tae-Hoon;Kim, Young-Jin;Han, Jung-Hee
    • IE interfaces
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    • v.18 no.3
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    • pp.277-287
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    • 2005
  • In this paper, we deal with a new techno-economic modeling and analysis for optical access networks. In deploying the fiber-to-the-home (FTTH) architecture, network planner needs to consider the following techno-economic issues: when do we need to upgrade existing local access network to FTTH network? how much do we invest to maximize profit? In order to answer these techno-economic questions, we need to consider the impact of emerging technologies and business environment. Toward this end, we develop a new techno-economic modeling to deal with the inherent complexity of technology evolution and cost economics. In particular, the new modeling approach provides us with an techno-economic analysis of technology alternatives such as ethernet passive optical network (E-PON) and wavelength division multiplex passive optical network (WDM-PON). In this analysis, we focus on the impact of critical factors such as the cost characteristic of proposed architecture and digital subscriber line (DSL) subscriber's churn-in to FTTH service and churn-out. We develop mixed integer-programming models for finding the evolution path of local access networks to broadband network architectures.

Behavior of Diffusion Layer Formation for TiNi/6061Al Smart Composites by Vacuum hot Press (진공 Hot Press법에 의한 TiNi/6061Al 지적 복합재료의 확산층 형성거동)

  • Park, Kwang-Hoon;Park, Sung-Ki;Shin, Soon-Gi;Lee, Jun-Hee
    • Korean Journal of Materials Research
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    • v.12 no.12
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    • pp.955-961
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    • 2002
  • 2.7vol%TiNi/6061 Al composites with TiNi shape memory alloy as reinforcement were fabricated by vacuum hot press. It was investigated by OM, SEM, EPMA and XRD analysis for the behavior of diffusion layer formation on various heat treatment condition. Thickness of diffusion layer was increased proportionally according to heat treatment time. The layer was formed by the mutual diffusion of TiNi and Al. The diffusion rate from TiNi fiber to Al matrix was faster than that of reverse diffusion path. The more diffused layer was formed in Al matrix. The diffusion at interface layer was consisted of $A1_3$Ti, $Al_3$Ni analyzed by EPMA, XRD results.

High Performance Wearable/Flexible Energy Storage Devices Based on Ultrathin $Ni(OH)_2$ Coated ZnO Nanowires

  • Shakir, Imran;Park, Jong-Jin;Kang, Dae-Joon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.597-597
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    • 2012
  • A simple solution-based method is developed to deposit crystalline ultrathin (2 nm) nickel hydroxide on vertically grown ZnO nanowires to achieve high specific capacitance and long-term life for flexible and wearable energy storage devices. Ultrathin crystalline $Ni(OH)_2$ enables fast and reversible redox reaction to improve the specific capacitance by utilizing maximum number of active sites for the redox reaction while vertically grown ZnO nanowires on wearable textile fiber effectively transport electrolytes and shorten the ion diffusion path. Under the highly flexible state $Ni(OH)_2$ coated ZnO nanowires electrode shows a high specific capacitance of 2150 F/g (based on pristine $Ni(OH)_2$ in 1 M LiOH aqueous solution with negligible decrease in specific capacitance after 1000 cycles. The synthesized energy-storage electrodes are easy-to-assemble which can provide unprecedented design ingenuity for a variety of wearable and flexible electronic devices.

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Vorticity Analysis Associated with Drafting Cylinders for Pneumatic Spinning

  • Bergada J.M.;Valencia E.;Coll Ll
    • Fibers and Polymers
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    • v.7 no.2
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    • pp.146-157
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    • 2006
  • Traditional spinning systems have reached profitability limits in developed countries due to high production costs and low system productivity. Pneumatic spinning is seen as a developing system, because productivity is much higher than conventional systems. This study evaluates one of the main problems to increase productivity in pneumatic spinning, where air mass-flow is dragged by the drafting cylinders. This flow interacts with the incoming fibres deviating them from their expected path. Via laser anemometry, airflow velocity distribution around drafting cylinders has been measured and it has been found that vorticity is created at the cylinder's inlet. Extensive CFD simulation on the air flow dragged by the cylinders has given a clear insight into the vortex created, producing valuable information on how cylinder design affects the vorticity created. Several drafting cylinder designs have been tested without giving any improvement in productivity. However, the use of a drafting cylinder with holes in it produced good results to the problem of air currents, strongly reducing them and therefore allowing a sharp increase in yarn quality, as well as an increase in productivity. An extensive study on vortex kinematics has been undertaken, bringing with it a better understanding of vortex creation, development and breakdown.

Detection of White Light Interference Peak Position utilizing Analog Signal Processing (아날로그 신호처리를 이용한 백색광 간섭 피크의 검출)

  • Yeh, Yun-Hae;Lee, Jong-Kwon
    • Korean Journal of Optics and Photonics
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    • v.16 no.4
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    • pp.319-325
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    • 2005
  • A signal processing method for white light interferometry (WLI), which performs a series of analog signal processing steps to locate the central interference fringe position at high speed: is developed and applied to a WLI temperature sensor system. We found that the new method has random walk of $0.019^{\circ}C/\sqrt{Hz}$ with good linearity. However, the temperature change in the path-matching interferometer results in drift of the measured sensor output. The temperature dependence of drift in the WLI temperature sensor system, was calculated to be $1.42{\mu}m/^{\circ}C$. It is also found that the relationship between the peak spacing in the interferogram and the spacing measured by the method can be nonlinear when the fringe spacing is comparable to the coherence length of the source.

Evaluation of Structural Stiffness Degradation and Burst Pressure Measurement of the FM Kick-Motor Combustion Case (킥모터 FM 규격 연소관에 대한 강성저하 평가 및 파열압력 측정)

  • Yi, Moo-Keun;Cho, In-Hyun;Kim, Joong-Suk;Lee, Won-Bok
    • Aerospace Engineering and Technology
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    • v.9 no.1
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    • pp.72-77
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    • 2010
  • A hydraulic test on a filament wound case of Kick-Motor was conducted to evaluate the structural stiffness degradation and to confirm the burst performance. Failure criteria have been defined with bursting above 150% of MEOP(Maximum Expected Operation Pressure) and failure in the cylinder. The analysis result showed that filament fiber in the cylinder should be broken at about 2088psig. From a hydraulic test it has been verified that composite case meets the failure requirements, and that the stiffness does not decrease even after a year since the manufacturing.

Comb-spacing-swept Source Using Differential Polarization Delay Line for Interferometric 3-dimensional Imaging

  • Park, Sang Min;Park, So Young;Kim, Chang-Seok
    • Current Optics and Photonics
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    • v.3 no.1
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    • pp.16-21
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    • 2019
  • We present a broad-bandwidth comb-spacing-swept source (CSWS) based on a differential polarization delay line (DPDL) for interferometric three-dimensional (3D) imaging. The comb spacing of the CSWS is repeatedly swept by the tunable DPDL in the multiwavelength source to provide depth-scanning optical coherence tomography (OCT). As the polarization differential delay of the DPDL is tuned from 5 to 15 ps, the comb spacing along the wavelength continuously varies from 1.6 to 0.53 nm, respectively. The wavelength range of various semiconductor optical amplifiers and the cavity feedback ratio of the tunable fiber coupler are experimentally selected to obtain optimal conditions for a broader 3-dB bandwidth of the multiwavelength spectrum and thus provide a higher axial resolution of $35{\mu}m$ in interferometric OCT imaging. The proposed CSWS-OCT has a simple imaging interferometer configuration without reference-path scanning and a simple imaging process without the complex Fourier transform. 3D surface images of a via-hole structure on a printed circuit board and the top surface of a coin were acquired.

The continuous-discontinuous Galerkin method applied to crack propagation

  • Forti, Tiago L.D.;Forti, Nadia C.S.;Santos, Fabio L.G.;Carnio, Marco A.
    • Computers and Concrete
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    • v.23 no.4
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    • pp.235-243
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    • 2019
  • The discontinuous Galerkin method (DGM) has become widely used as it possesses several qualities, such as a natural ability to dealing with discontinuities. DGM has its major success related to fluid mechanics. Its major importance is the ability to deal with discontinuities and still provide high order of approximation. That is an important advantage when simulating cracking propagation. No remeshing is necessary during the propagation, since the crack path follows the interface of elements. However, DGM comes with the drawback of an increased number of degrees of freedom when compared to the classical continuous finite element method. Thus, it seems a natural approach to combine them in the same simulation obtaining the advantages of both methods. This paper proposes the application of the combined continuous-discontinuous Galerkin method (CDGM) to crack propagation. An important engineering problem is the simulation of crack propagation in concrete structures. The problem is characterized by discontinuities that evolve throughout the domain. Crack propagation is simulated using CDGM. Discontinuous elements are placed in regions with discontinuities and continuous elements elsewhere. The cohesive zone model describes the fracture process zone where softening effects are expressed by cohesive zones in the interface of elements. Two numerical examples demonstrate the capacities of CDGM. In the first example, a plain concrete beam is submitted to a three-point bending test. Numerical results are compared to experimental data from the literature. The second example deals with a full-scale ground slab, comparing the CDGM results to numerical and experimental data from the literature.

Closed-form solution for the buckling behavior of the delaminated FRP plates with a rectangular hole using super-elastic SMA stitches

  • Soltanieh, Ghazaleh;Yam, Michael CH.;Zhang, Jing-Zhou;Ke, Ke
    • Structural Engineering and Mechanics
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    • v.81 no.1
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    • pp.39-50
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    • 2022
  • Layer separation (delamination) is an essential threat to fiber-reinforced polymer (FRP) plates under dynamic, static, and fatigue loads. Under compressive load, the growth of delamination will lead to structural instability. The aim of this paper is to present a method using shape memory alloy (SMA) stitches to suppress the delamination growth in a FRP plate and to improve the buckling behavior of the plate with a rectangular hole. The present paper is divided into two parts. Firstly, a closed-form (CF) formulation for evaluating the buckling load of the FRP plate is presented. Secondly, the finite element method (FEM) will be employed to calculate the buckling loads of the plates which serves to validate the results obtained from the closed-form method. The novelty of this work is the development of the closed-form solution using the p-Ritz energy approach regarding the stress-dependent phase transformation of SMA to trace the equilibrium path. For the FEM, the Lagoudas constitutive model of the SMA material is implemented in FORTRAN programming language using a user material subroutines (VUMAT). The model is simulated in ABAQUS/Explicit solver due to the nature of the loading type. The cohesive zone model (CZM) is applied to simulate the delamination growth.

Manufacture and Qualification of Composite Main Reflector of High Stable Deployable Antenna for Satellite (위성용 전개형 고안정 반사판 안테나 주반사판 제작 및 검증)

  • Dong-Geon Kim;Hyun-Guk Kim;Dong-Yeon Kim;Kyung-Rae Koo;Ji-min An;O-young Choi
    • Composites Research
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    • v.37 no.3
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    • pp.219-225
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    • 2024
  • It is essential to develop a light-weight, high-performance structure for the deployable reflector antenna, which is the payload of a reconnaissance satellite, considering launch and orbital operation performance. Among them, the composite main reflector is a key component that constitutes a deployable reflector antenna. In particular, the development of a high-performance main reflector is required to acquire high-quality satellite images after agile attitude control maneuvers during satellite missions. To develop main reflector, the initial design of the main reflector was confirmed considering the structural performance according to the laminate stacking design and material properties of the composite main reflector that constitutes the deployable reflector antenna. Based on the initial design, four types of composite main reflectors were manufactured with the variable for manufacturing process. As variables for manufacturing process, the curing process of the composite structure, the application of adhesive film between the carbon fiber composite sheet and the honeycomb core, and the venting path inside the sandwich composite were selected. After manufacture main reflector, weight measurement, non-destructive testing(NDT), surface error measurement, and modal test were performed on the four types of main reflectors produced. By selecting a manufacturing process that does not apply adhesive film and includes venting path, for a composite main reflector with light weight and structural performance, we developed and verified a main reflector that can be applied to the SAR(Synthetic Aperture Rader) satellite.