• Title/Summary/Keyword: Effective free distance

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A Modified Range-free localization algorithm for Wireless Sensor Networks (무선 센서 네트워크를 위한 개선된 Range-free 위치인식 알고리즘)

  • Ekale, Etinge Martin;Lee, Chaewoo
    • Proceedings of the Korea Information Processing Society Conference
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    • 2010.11a
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    • pp.829-832
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    • 2010
  • Wireless Sensor Networks have been proposed for several location-dependent applications. For such systems, the cost and limitations of the hardware on sensing nodes prevent the use of range-based localization schemes that depend on absolute point to point distance estimates. Because coarse accuracy is sufficient for most sensor network applications, solutions in range-free localization are being pursued as a cost-effective alternative to more expensive range-based approaches. In this paper, we proposed a modified DV-Hop (range-free localization) algorithm which reduces node's location error and cumulated distance error by minimizing localization error. Simulation results have verified the high estimation accuracy with our approach which outperforms the classical DV-Hop.

Design of a Turbo Decoder (Turbo decoder의 설계)

  • 박성진;송인채
    • Proceedings of the IEEK Conference
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    • 2000.11b
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    • pp.277-280
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    • 2000
  • In this paper, we designed a turbo decoder using VHDL. To maximize effective free distance of the turbo code, we implemented pseudo random interleaver. A MAP(Maximum a posteriori) decoder is used as a primimary decoder. We avoided multiplication by using lookup tables(ROM). We expect that this small-sized turbo decoder is suitable for mobile communication. We simulated turbo decoder with Altera MAX+PLUS II.

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Influence of Spring Constant and Tip Mass at Free End on Stability of Timoshenko Cantilever Column subjected to a Follower Force (자유단의 스프링 상수와 부가 말단질량이 종동력을 받는 Timoshenko 외팔보의 안정성에 미치는 영향)

  • 손종동
    • Journal of the Korean Society of Safety
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    • v.13 no.4
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    • pp.49-58
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    • 1998
  • On the stability of the Timoshenko cantilever column subjected of a compressive follower force, the influences of the moment of inertia of the tip mass at the free end and the characteristics of a translational spring at the free end of the column are studied. The equations of motion and boundary conditions of system are estabilished by using the d'Alembert virtual work of principle. On the evaluation of stability of the column, the effect of the shear deformation and rotatory inertia is considered in calculation. The moment of inertia of the tip mass at the free end of the column is changed by adjusting the distance c, from the free end of the column to the tip mass center. The free end of the column is supported elastically by a translational spring. For the maintenance of the good stability of the column, it is also proved that the constant of the translational spring at the free end must be very large for the case without a tip mass while it must be small for the case with a tip mass. Therefore, it is found that the shape of the tip mass and the characteristic of the spring at the free end are very effective elements for the stability of the column when the columns subjected to a compressive follower force are designed.

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Design of Recursive Systematic Convolutional Codes for Turbo Codes Based on the Distance Spectrum Properties (거리 분포 특성에 근거한 터보 부호의 순환 조직형 컨벌루션 부호 설계)

  • Kim, Dae-Son;Song, Hong-Yeop;Lee, Dong-Hahk;Yu, Jae-Hwang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.2C
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    • pp.155-160
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    • 2008
  • In this letter, we propose a new design of recursive systematic convolutional (RSC) codes based on the distance spectrum properties which can maximize the performance. Good constituent RSC codes of code rate 1/2 are searched by computer and presented in a table. Their performances are shown by computer simulation. New designed codes shows faster convergences according to iterative decoding and good performances.

A Data Fusion Method of Odometry Information and Distance Sensor for Effective Obstacle Avoidance of a Autonomous Mobile Robot (자율이동로봇의 효율적인 충돌회피를 위한 오도메트리 정보와 거리센서 데이터 융합기법)

  • Seo, Dong-Jin;Ko, Nak-Yong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.4
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    • pp.686-691
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    • 2008
  • This paper proposes the concept of "virtual sensor data" and its application for real time obstacle avoidance. The virtual sensor data is virtual distance which takes care of the movement of the obstacle as well as that of the robot. In practical application, the virtual sensor data is calculated from the odometry data and the range sensor data. The virtual sensor data can be used in all the methods which use distance data for collision avoidance. Since the virtual sensor data considers the movement of the robot and the obstacle, the methods utilizing the virtual sensor data results in more smooth and safer collision-free motion.

PMDV-hop: An effective range-free 3D localization scheme based on the particle swarm optimization in wireless sensor network

  • Wang, Wenjuan;Yang, Yuwang;Wang, Lei;Lu, Wei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.1
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    • pp.61-80
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    • 2018
  • Location information of individual nodes is important in the implementation of necessary network functions. While extensive studies focus on localization techniques in 2D space, few approaches have been proposed for 3D positioning, which brings the location closer to the reality with more complex calculation consumptions for high accuracy. In this paper, an effective range-free localization scheme is proposed for 3D space localization, and the sensitivity of parameters is evaluated. Firstly, we present an improved algorithm (MDV-Hop), that the average distance per hop of the anchor nodes is calculated by root-mean-square error (RMSE), and is dynamically corrected in groups with the weighted RMSE based on group hops. For more improvement in accuracy, we expand particle swarm optimization (PSO) of intelligent optimization algorithms to MDV-Hop localization algorithm, called PMDV-hop, in which the parameters (inertia weight and trust coefficient) in PSO are calculated dynamically. Secondly, the effect of various localization parameters affecting the PMDV-hop performance is also present. The simulation results show that PMDV-hop performs better in positioning accuracy with limited energy.

Does the China-Korea Free Trade Area Promote the Green Total Factor Productivity of China's Manufacturing Industry?

  • Liu, Zuan-Kuo;Cao, Fei-Fei;Dennis, Bolayog
    • Journal of Korea Trade
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    • v.23 no.5
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    • pp.27-44
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    • 2019
  • Purpose - The purpose of this paper is to analyze the net effect of the green total factor productivity (GTFP) of China's manufacturing industry from the China-Korea Free Trade Area (China-Korea FTA) quantitatively. Design/methodology - Firstly, the Global Malmquist-Luenberger (GML) index based on the SBM directional distance function is used to measure the GTFP of China's manufacturing and analyze the driving force for its growth. Secondly, the regression discontinuity quantitative analysis is used to determine the impact of the China-Korea FTA on China's manufacturing GTFP. Findings - Our main findings can be summarized as follows: the China-Korea FTA has promoted the GTFP of China's manufacturing with an effect evaluation mainly resulting from green technology progress. And there is industry heterogeneity in the policy effect on the manufacturing GTFP due to the China-Korea FTA. Namely, policy promotion from the China-Korea FTA is more effective on the GTFP of equipment manufacturing than it is on those of other industries. Originality/value - First, an evaluation and analysis of the GTFP development of China's manufacturing that employs GML index based on SBM directional distance function. Second, a quantitative estimate of China-Korea FTA's net effect on China's manufacturing industrial GTFP that uses regression discontinuity analysis, which is considered to be the closest method to natural experiments and superior to other causal inference methods. Third, an in-depth discussion of the practical steps that China's manufacturing can take to improve GTFP development and integrate China-Korea FTA construction into economic development.

The Optimization of RF Atmospheric Pressure Plasma Treatment Process for Improving the Surface Free Energy of Polymethylmethacrylate (PMMA) (Polymethylmethacrylate (PMMA) 표면개질을 위한 RF 대기압 플라즈마 처리공정의 최적화)

  • Nam, Ki-Chun;Myung, Sung-Woon;Choi, Ho-Suk
    • Journal of Adhesion and Interface
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    • v.6 no.3
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    • pp.1-9
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    • 2005
  • This study investigated the influence of atmospheric plasma factors such as RF power, treatment time, the gap distance between discharge and sample, and the gas flow rate of Ar on the surface property by using the design of experiment (DOE) method. The plasma treatment time (s), plasma power (W), gap distance (mm) between discharge and sample, and flow rate of Ar gas were in order of important factors for changing the surface free energy of PMMA plates. As a result, the most effective factor for improving the surface free energy of PMMA plates is the distance (mm) from discharge glow to sample plate. Because of the interaction between plasma power (W) and treatment time (s), the power dose (J) factor which multiply plasma power (W) by treatment time (s) should be significantly considered. The optimum condition for maximizing the surface free energy of PMMA plate was found at 1500J of power dose. Through XPS and AFM analysis, we also observed the change of chemical composition, surface morphology and roughness before and after plasma treatment. It is considered that the change of surface free energy of PMMA plate with plasma treatment is influenced by the introduction of polar functional group as well as the increase of surface roughness.

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A Study on the Effective Free Surface of Fluid Cargo (유동화물의 유효자유표면에 관한 연구)

  • Hur, I.;Wang, J.S.
    • Journal of the Korean Institute of Navigation
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    • v.11 no.2
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    • pp.73-88
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    • 1987
  • It is well known that the height of tank metacenter above the centroid of fluid in a tank is given by i/v where I is the inertia moment of free surface and v is the fluid volume. It is supposed in this formula that the inclination of ship is small and that the free surface of fluid do not touch the top and the bottom of tank. It the inclination of ship is large, the height of tank metacenter may be possibly greater than that given by i/v. The height of tank metacenter is smaller than i/v when the free surface of fluid touch the top or the bottom of tank. The reasonable method to calculate the height of tank metacenter is presented in this paper and prepared in FORTRAN program by FUNCTION EFFRES. The approximate formula was also developed and given by $g_m=(1+\frac{2}{1}tan^2\theta)[1-EXP\{-12(\frac{\alpha(1-\alpha)k}{tan\theta})^{1.25}\}]\frac{i}{v}$ where $g_m$ is the distance from the centroid of fluid to the tank metacenter, $\theta$ is inclined angle of ship, $\alpha$ is the ratio of filled volume to tank capacity and k is the ratio of the depth to the width of tank. The values calculated by the approximate formula given in this paper were compared with the exact values from the computer program and proved out to be sufficiently precise for practical use.

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Determination of the Magnetic Moment of ${\alpha}-Fe_{2}O_{3}$ of the Parasitic Ferromagnetism by the Proton Relaxation in Water (물의 양성자완화에 의한 기생 강자성 ${\alpha}-Fe_{2}O_{3}$의 자기능률 결정)

  • Yong-Jin Kim;Jung-Gi Kim
    • Journal of the Korean Magnetics Society
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    • v.4 no.3
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    • pp.282-284
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    • 1994
  • A theoretical expression for determining the effective magnetic moment of hematite(${\alpha}-Fe_{2}O_{3}$) particle of the parasitic ferromagnetism by the proton relaxation in water is derived. In deriving the expression it is found that the mathematical procedures are exactly the same as those applied for aqueous solutions containing free paramagnetic ions, except that the distance between the proton spin of water molecule and the corresponding electronic spin of the particle must be considered to be a radius vector rather than a relative distance. And it is also found that the average effective magnetic moment of the particle calculated by the expression is in good agreement with the experimental value determined by Hirai.

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