• Title/Summary/Keyword: Separation delay

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Development of Non-Electric and Delay Explosive Bolt (비전기식 지연형 폭발볼트 개발)

  • Lee YeungJo;Kim DongJin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • v.y2005m4
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    • pp.92-95
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    • 2005
  • The present work has been developed the type of non-electric and delay explosive bolt which does not need power supply device and has the delay function in the operation of the explosive bolt. Separation device system could be minimized because of non-electric power supply system. In order to prove the mechanism of operation, the present work used to ignite the initiator the power of air resistance caused front aviation object. we can be founded from the present work that the changes in the operation load influence directly the ignition of the initiator. The design of non-electric and delay explosive bolt is the most suitable the separation system necessary to reduce the velocity of aviation object and safe landing of parachute system.

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Development of Non-Electric and Delay-Type Explosive Bolt (비전기식 지연형 폭발볼트 개발)

  • Lee YeungJo;Kim DongJin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.9 no.3
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    • pp.60-65
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    • 2005
  • The present work has developed non-electric and delay-type explosive bolt that does not need electric power supply device and has the delay function in the operation. Non-electric power supply system enables separation device system to be minimized. In order to prove the mechanism of the operation, the power of air resistance caused from aviation object used to ignite the initiator. we can be founded from the present work that the changes in the operation load influence directly the ignition of the initiator. The design of non-electric and delay type of explosive bolt is the most suitable for the separation system that is necessary to reduce the velocity of aviation object and safe landing of parachute system.

Mechanism of Drag Reduction by Dimples and Roughness on a Sphere (구에 설치한 딤플과 표면 거칠기에 의한 항력 감소 메커니즘)

  • Choi, Jin;Jeon, Woo-Pyung;Choi, Hae-Cheon
    • 유체기계공업학회:학술대회논문집
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    • 2006.08a
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    • pp.191-194
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    • 2006
  • In this paper, we present a detailed mechanism of drag reduction by dimples and roughness on a sphere by measuring the streamwise velocity above the dimpled and roughened surfaces, respectively. Dimples cause local flow separation and trigger the shear layer instability along the separating shear layer, resulting in generation of large turbulence intensity. With this increased turbulence, the flow reattaches to the sphere surface with high momentum near the wall and overcomes strong adverse pressure gradient formed in the rear sphere surface. As a result, dimples delay main separation and reduce drag significantly. The present study suggests that generation of a separation bubble, i.e. a closed-loop streamline consisting of separation and reattachment, on a body surface is an important flow-control strategy for drag reduction on a bluff body such as the sphere and cylinder. In the case of roughened sphere, the boundary layer flow is directly triggered by roughness and changes to a turbulent flow. Due to this change, the drag significantly decreases. As the Reynolds number further increases, transition to turbulence occurs earlier on the sphere surface. Because of faster growth of turbulent boundary layer by roughness, earlier transition thickens the boundary layer, resulting in earlier separation and drag increase with increasing Reynolds number

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Effect of stall delay characteristics of symmetrical aerofoil using lateral circular ridges

  • Raatan, V.S.;Ramaswami, S.;Mano, S.;Pillai, S. Nadaraja
    • Wind and Structures
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    • v.34 no.4
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    • pp.385-394
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    • 2022
  • Global Warming has been driven majorly by the consumption of fossil fuels. Harnessing energy from wind is viable solution towards reducing carbon footprint created due to burning such fuels, However, wind turbines have their problems of flow separation and aerodynamic stall to tackle with. In an attempt to delay the stall angle and improve the aerodynamic characteristics of the NACA 0015 symmetrical aerofoil, lateral cylindrical ridges were attached to its suction surface, at chord positions ranging from 0.1c to 0.5c. The characteristics of the original and ridged aerofoils were obtained using simultaneous pressure readings taken in a wind tunnel, at a free stream Reynolds number of Re = 2.81 × 105 for a wide range of free stream angles of attack ranging from -45° to 45°. Depending on the ridge size, a delay in stall angle varying from 5° to 20° was achieved together with the maximum increase in lift in the post-stall phases. Additionally, efforts were made to identify the optimum position for each ridge.

An Analysis of the Effects of Walking Guidance System in Subway Stations using Genetic Algorithm (유전 알고리즘을 이용한 지하철 역사 동선 분리 시스템의 효과 분석)

  • Kim, Jin-Ho;Lee, Joo-Yong;Kim, Tae-Wan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.3
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    • pp.617-624
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    • 2015
  • The conflict of opposing pedestrian traffic-flow in a subway station(made up of stair, passageway, and escalator) diminishes the convenience and mobility of its users. In addition, the station's efficiency would be negatively affected by the growth of delay and queue length in pedestrian facilities. As these phenomena have been resulted by the overlapping in pedestrian's traffic-line, the separation of it would alleviate these problems. For the criteria and methodology of separation, this paper has investigated the bi-directional queue length and delay on the entrance of each facility (stair, passageway and escalator). Since the pedestrian flow exists bidirectionally, we have used the weighted average by inflow rate for the delay value. For the optimization of the separation, the Genetic Algorithm has been utilized in order to minimize the delay.

Design and Implementation of In-band Interference Reduction Module (동일대역 간섭저감기의 설계 및 구현)

  • Kang, Sanggee;Hong, Heonjin;Chong, Youngjun
    • Journal of IKEEE
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    • v.24 no.4
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    • pp.1028-1033
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    • 2020
  • The existing in-band interference reduction method recommends the physical separation distance between wireless devices and interference signals, and the interference can be suppressed through the separation distance. If the in-band interference signals can be reduced in a wireless device, a margin can be given to the physical separation distance. Since there is an effect of extending the receiver dynamic range of receivers, it is highly useful for interference reduction and improvement method. In this paper, the structure of an in-band analog IRM(Interference Reduction Module) is proposed and the design and implementation of the proposed analog IRM are described. To design an analog IRM, the interference reduction performance according to the delay mismatch, phase error and the number of delay lines that affect the performance of the analog IRM was simulated. The proposed analog IRM composed of 16 delay lines was implemented and the implemented IRM has the interference reduction performance of about 10dB for a 5G(NR-FR1-TM-1.1) signal having a 40MHz bandwidth at a center frequency of 3.32GHz. The analog IRM proposed in this paper can be used as an in-band interference canceller.

SOLUTIONS OF A CLASS OF COUPLED SYSTEMS OF FUZZY DELAY DIFFERENTIAL EQUATIONS

  • Wu, Yu-ting;Lan, Heng-you;Zhang, Fan
    • Nonlinear Functional Analysis and Applications
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    • v.26 no.3
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    • pp.513-530
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    • 2021
  • The purpose of this paper is to introduce and study a class of coupled systems of fuzzy delay differential equations involving fuzzy initial values and fuzzy source functions of triangular type. We assume that these initial values and source functions are triangular fuzzy functions and define solutions of the coupled systems as a triangular fuzzy function matrix consisting of real functional matrices. The method of triangular fuzzy function, fractional steps and fuzzy terms separation are used to solve the problems. Furthermore, we prove existence and uniqueness of solution for the considered systems, and then a solution algorithm is proposed. Finally, we present an example to illustrate our main results and give some work that can be done later.

Blind Source Separation of Instantaneous Mixture of Delayed Sources Using High-Order Taylor Approximation

  • Zhao, Wei;Yuan, Zhigang;Shen, Yuehong;Cao, Yufan;Wei, Yimin;Xu, Pengcheng;Jian, Wei
    • ETRI Journal
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    • v.37 no.4
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    • pp.727-735
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    • 2015
  • This paper deals with the problem of blind source separation (BSS), where observed signals are a mixture of delayed sources. In reference to a previous work, when the delay time is small such that the first-order Taylor approximation holds, delayed observations are transformed into an instantaneous mixture of original sources and their derivatives, for which an extended second-order blind identification (SOBI) approach is used to recover sources. Inspired by the results of this previous work, we propose to generalize its first-order Taylor approximation to suit higher-order approximations in the case of a large delay time based on a similar version of its extended SOBI. Compared to SOBI and its extended version for a first-order Taylor approximation, our method is more efficient in terms of separation quality when the delay time is large. Simulation results verify the performance of our approach under different time delays and signal-to-noise ratio conditions, respectively.

Compensation of Network Delay Using Predictive Controller (예측제어기를 이용한 네트워크 시간지연 보상)

  • 허화라;박재한이장명
    • Proceedings of the IEEK Conference
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    • 1998.06a
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    • pp.243-246
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    • 1998
  • A predictive controller is designed based upon stochastic methods for compensation of network time delay which caused by the spatial separation between controllers and actuators. Current commands are generated by using time varying probability functions which can be defined according to the values of previous control inputs and actual outputs. To demonstrate the effect of this control methodology, simulation experiments are performed. The results show that even an unstabilized system by a long time delay can be stabilized with this predictive controller.

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Input Time-Delay Compensation for a Nonlinear Control System

  • Choi, Yong-Ho;Chong, Kil-To
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.395-400
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    • 2004
  • In most physical processes, the transfer function includes time-delay, and in the general distributed control system using computer network, there exists inherent time-delay caused by the spatial separation between controllers and actuators. This work deals with the synthesis of a discrete-time controller for a nonlinear system and proposes a new effective method to compensate the influence of input time-delay. The controller is synthesized by using input/output linearization. Under the circumstance that input time-delay exists, the system response has more overshoot and tends to diverge. For these reasons, the controller has to produce future input value that will be needed for the system. In order to calculate the future input value, some predictors are adopted. Using the discretization via Euler's method, numerical simulations about the Van der Pol system are performed to evaluate the performance of the proposed method.

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