• Title/Summary/Keyword: V2X technology

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A Study on V2V Communication Environment in K-city (자율주행 실험도시(K-city) 내 V2V 통신 환경에 관한 연구)

  • Jo, Byeongchan;Kim, Donghwan;Shin, Jaekon;Kim, Sungsub;Cho, Seongwoo
    • Journal of Auto-vehicle Safety Association
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    • v.13 no.1
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    • pp.26-30
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    • 2021
  • K-city is an experimental area for developing self-driving cars. V2X communications such as WAVE, C-V2X and 5G are an essential technology for autonomous driving above level 4. In this paper, the research on the V2V communication environment was carried out through BSM receiving level analysis on the driving route in K-city. A stationary vehicle communicated with a test vehicle moving along urban area and suburban road in two different scenarios. The communication range and receiving levels obtained from this study will be used to develop and verify various safety scenarios using V2V communication within K-city in the future.

Crystal growth and photocurrent of $Mg_{x}Zn_{1-x}$Te single crystals ($Mg_{x}Zn_{1-x}$Te 단결정 성장과 광전류 특성)

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    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.11 no.1
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    • pp.6-13
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    • 2001
  • By using a vertical Bridgeman method, single crystalline structures of $Mg_xZn_{1-x}Te(0{\le}X{\le}0.48)$ were grown for various Mg mole compositions. With the increasing Mg fraction, the lattice constant is linearly increased from 6.103 to 6.239$\AA$ for the range of $0{\le}X{\le}0.48$ and the lattice constant of zincblende MgTe was linearly extrapolated to the value of 6.433$\pm$0.002$\AA$. The optical properties of the crystalline structure were characterized with photocurrent measurements. As a results of photocurrent spectra, the single crystalline $Mg_xZn_{1-x}Te$ show the energy bandgap of 2.380 and 2.260eV at 4.2 and 294 K, respectively. The photocurrent peak blueshifts with increasing Mg mole fraction and show the linear dependence of energy bandgap, $E_g$(X)=b+(0.8)X. The extrapolation shows the energy bandgaps of MgTe of 3.18 and 3.06eV at the temperatures of 4.2 and 294K, respectively. Furthermore, the photocurrent peaks redshifts with increasing temperature and the temperature coefficient is given to the value of $dE_g$/dT=-(5.6~$6.1){\times}10^{-4}$eV/K. for the temperature range above 100K.

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Synthesis and X-ray Crystal Structure of the Ethylenediammonium Monohydric Phosphate (Ethylenediammonium Monohydric Phosphate의 합성 및 X-선 결정구조)

  • Tae-Sun Chang;Chong-Hyeak Kim;Deug-Hee Cho;Dong-Koo Lee;Tianyou Song
    • Korean Journal of Crystallography
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    • v.13 no.2
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    • pp.96-100
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    • 2002
  • The title compound, (H/sub 3/NCH/sub 2/CH/sub 2/NH/sub 3/)HPO/sub 4/ (Ⅰ), has been synthesized by hydrothermal technique for the first time and its novel structure analyzed by X-ray single crystallography. The compound (Ⅰ) crystallizes in the monoclinic system, P2/sub 1//c space group with a=10.209(1), b=7.891(1), c= 8.039(1) (equation omitted), β= 92.138(9)°, V=: 647.2(2) (equation omitted), Z=4, R/sub 1/=0.0295 and ωR/sub 2/=0.0811 for 1141 independent reflections. The compound (Ⅰ) is interconnected to give a three-dimensional network through hydrogen-bonding interactions.

Realistic and Efficient Radio Propagation Model for V2X Communications

  • Khokhar, Rashid Hafeez;Zia, Tanveer;Ghafoor, Kayhan Zrar;Lloret, Jaime;Shiraz, Muhammad
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.8
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    • pp.1933-1954
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    • 2013
  • Multiple wireless devices are being widely deployed in Intelligent Transportation System (ITS) services on the road to establish end-to-end connection between vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) networks. Vehicular ad hoc networks (VANETs) play an important role in supporting V2V and V2I communications (also called V2X communications) in a variety of urban environments with distinct topological characteristics. In fact, obstacles such as big buildings, moving vehicles, trees, advertisement boards, traffic lights, etc. may block the radio signals in V2X communications. Their impact has been neglected in VANET research. In this paper, we present a realistic and efficient radio propagation model to handle different sizes of static and moving obstacles for V2X communications. In the proposed model, buildings and large moving vehicles are modeled as static and moving obstacles, and taken into account their impact on the packet reception rate, Line-of-sight (LOS) obstruction, and received signal power. We use unsymmetrical city map which has many dead-end roads and open faces. Each dead-end road and open faces are joined to the nearest edge making a polygon to model realistic obstacles. The simulation results of proposed model demonstrates better performance compared to some existing models, that shows proposed model can reflect more realistic simulation environments.

Optimization of Extraction of Effective Components from Vitis coignetiae, the Crimson Glory Vine (산머루 유용성분 추출공정의 최적화)

  • Jo, In-Hee;Kim, Chang-Youn;Lee, Tae-Wook;Lee, Geun-Ho;Choi, Yong-Hee
    • Food Science and Preservation
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    • v.17 no.5
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    • pp.659-666
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    • 2010
  • A central composite design was used to investigate the effects of the three independent variables of extraction temperature ($X_1$), ethanol concentration ($X_2$), and extraction time ($X_3$), on dependent variables including yield ($Y_1$), total phenol levels ($Y_2$), electron-donating ability ($Y_3$), brownness ($Y_4$), and reducing sugar content ($Y_5$) of Vitis Coignetiae. Yield was affected by extraction temperature and time. The maximum yield was obtained at $91.62^{\circ}C(X_1)$, and, 25.37% (w/v) ethanol ($X_2$), after 317.70 min of extraction ($X_3$), evident as a saddle when displayed graphically. Total phenol levels were essentially unaffected by extraction temperature or ethanol concentration, but were highly influenced by extraction time. The maximum total phenol levels was 4,763.46 GAE mg/100 g obtained at $88.20^{\circ}C(X_1)$, and 47.79% (w/v) ethanol ($X_2$), after 349.32 min ($X_3$) of extraction. Electron-donating ability (EDA) was affected by extraction temperature and time. Maximum EDA was 55.90% at $86.72^{\circ}C(X_1)$, 50.61% (w/v) ethanol ($X_2$), and 265.96 min ($X_3$) of extration time, again shown by a graphical saddle. Brownness was affected by extraction time. The maximum extent of brown coloration was obtained at $82.66^{\circ}C(X_1)$, 99.27% (w/v) ethanol ($X_2$), and 252.63 min of extraction time ($X_3$), once again shown by graphical saddle. The maximum reducing sugar content was obtained at $96.24^{\circ}C(X_1)$, 22.59% (w/v) ethanol ($X_2$), and 216.06 min extraction time($X_3$).

Excess Volumes of Aqueous Solutions of Nonionic Amphiphile 2-(2-Hexyloxyethoxy)ethanol (비이온 양친매성 분자 2-(2-Hexyloxyethoxy)ethanol 수용액의 과잉 부피)

  • Lee, Jungno;Hwang, Yoonmi;Kang, Minhee;Lim, Kyung-Hee
    • Journal of the Korean Applied Science and Technology
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    • v.37 no.3
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    • pp.516-525
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    • 2020
  • The densities of aqueous solutions of the amphiphile 2-(2-hexyloxyethoxy)ethanol (C6E2) were measured at 279.15 K and 282.15 K by vibrating-tube densitometry. Then using the density data of the binary C6E2 (1)/water(2) system, the excess volumes and partial molar volumes were determined at various compositions. Excess volume VE exhibits negative deviation for the whole region of composition, which implies relatively stronger attraction between molecules. At the C6E2 mole fraction of around 0.45, VE was at its minimum. Partial molar volume ${\bar{V}}_1$ increases monotonously with the mole fraction x1(=x) and ${\bar{V}}_2$ decreases with x. Any particular point in ${\bar{V}}_1$ and ${\bar{V}}_2$, which may point to molecular association, was unobserved.

Electrical Properties of ZnxMn3-xO4 Ceramics for Application as IR Detectors

  • Kim, Kyeong-Min;Lee, Sung-Gap;Lee, Dong-Jin
    • Transactions on Electrical and Electronic Materials
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    • v.17 no.4
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    • pp.227-230
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    • 2016
  • ZnxMn3-xO4 (0.95≤x≤1.20) specimens were prepared using a conventional solid state reaction method. All specimens were sintered in air at 1,200℃ for 12 h, cooled at a rate of 2℃/min to 800℃, and subsequently quenched to room temperature. We investigated the electrical properties of ZnxMn3-xO4 specimens with various amounts of ZnO for use as IR detectors. At a composition of x≥1.15, the ZnO phase precipitates beside the spinel structure. The electrical resistivity at room temperature, activation energy, responsivity, and detectivity of a Zn1.10Mn1.90O4 specimen are 653.2 kΩ-cm, 0.392 eV, 0.016 V/W, and 7.52×103 cmHz1/2/W, respectively.

THE INTEGRAL EXPRESSION INVOLVING THE FAMILY OF LAGUERRE POLYNOMIALS AND BESSEL FUNCTION

  • Shukla, Ajay Kumar;Salehbhai, Ibrahim Abubaker
    • Communications of the Korean Mathematical Society
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    • v.27 no.4
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    • pp.721-732
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    • 2012
  • The principal aim of the paper is to investigate new integral expression $${\int}_0^{\infty}x^{s+1}e^{-{\sigma}x^2}L_m^{(\gamma,\delta)}\;({\zeta};{\sigma}x^2)\;L_n^{(\alpha,\beta)}\;({\xi};{\sigma}x^2)\;J_s\;(xy)\;dx$$, where $y$ is a positive real number; $\sigma$, $\zeta$ and $\xi$ are complex numbers with positive real parts; $s$, $\alpha$, $\beta$, $\gamma$ and $\delta$ are complex numbers whose real parts are greater than -1; $J_n(x)$ is Bessel function and $L_n^{(\alpha,\beta)}$ (${\gamma};x$) is generalized Laguerre polynomials. Some integral formulas have been obtained. The Maple implementation has also been examined.

An optimal security management framework for backhaul-aware 5G- Vehicle to Everything (V2X)

  • Vishal Sharma;Jiyoon Kim;Yongho Ko;Ilsun You;Jung Taek Seo
    • Journal of Internet Technology
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    • v.21 no.1
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    • pp.249-264
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    • 2020
  • Cellular (C) setups facilitate the connectivity amongst the devices with better provisioning of services to its users. Vehicular networks are one of the representative setups that aim at expanding their functionalities by using the available cellular systems like Long Term Evolution (LTE)-based Evolved Universal Terrestrial Radio Access Network (E-UTRAN) as well as the upcoming Fifth Generation (5G)-based functional architecture. The vehicular networks include Vehicle to Vehicle (V2V), Vehicle to Infrastructure (V2I), Vehicle to Pedestrian (V2P) and Vehicle to Network (V2N), all of which are referred to as Vehicle to Everything (V2X). 5G has dominated the vehicular network and most of the upcoming research is motivated towards the fully functional utilization of 5G-V2X. Despite that, credential management and edge-initiated security are yet to be resolved under 5G-V2X. To further understand the issue, this paper presents security management as a principle of sustainability and key-management. The performance tradeoff is evaluated with the key-updates required to maintain a secure connection between the vehicles and the 5G-terminals. The proposed approach aims at the utilization of high-speed mmWave-based backhaul for enhancing the security operations between the core and the sub-divided functions at the edge of the network through a dual security management framework. The evaluations are conducted using numerical simulations, which help to understand the impact on the sustainability of connections as well as identification of the fail-safe points for secure and fast operations. Furthermore, the evaluations help to follow the multiple tradeoffs of security and performance based on the metrics like mandatory key updates, the range of operations and the probability of connectivity.

NOTE ON CONNECTED (g, f)-FACTORS OF GRAPHS

  • Zhou, Sizhong;Wu, Jiancheng;Pan, Quanru
    • Journal of applied mathematics & informatics
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    • v.28 no.3_4
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    • pp.909-912
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    • 2010
  • In this note we present a short proof of the following result by Zhou, Liu and Xu. Let G be a graph of order n, and let a and b be two integers with 1 $\leq$ a < b and b $\geq$ 3, and let g and f be two integer-valued functions defined on V(G) such that a $\leq$ g(x) < f(x) $\leq$ b for each $x\;{\in}\;V(G)$ and f(V(G)) - V(G) even. If $n\;{\geq}\;\frac{(a+b-1)^2+1}{a}$ and $\delta(G)\;{\geq}\;\frac{(b-1)n}{a+b-1}$,then G has a connected (g, f)-factor.