فهرست مطالب

Communication Engineering - Volume:5 Issue: 1, Spring 2016

Journal of Communication Engineering
Volume:5 Issue: 1, Spring 2016

  • تاریخ انتشار: 1395/02/28
  • تعداد عناوین: 6
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  • Mohammad Ehdaie*, Nikolaos Alexiou, Panos Papadimitratos Pages 1-13
    Sybil attacks pose a serious threat for Wireless Sensor Networks (WSN) security. They can create problems in routing, voting schemes, decision making, distributed storage and sensor re-programming. In a Sybil attack, the attacker masquerades as multiple sensor identities, that are actually controlled by one or a few existing attacker nodes. Sybil identities are fabricated out of stolen keys, obtained by captured benign nodes. Existing Sybil defensive mechanisms suffer from the restricted sensor network size, or cause excessive resource consumption for the sensor network. In this work we propose a Sybil node detection mechanism, based on Random Key Distribution (RKD) schemes that can cope with large network sizes and minimize the waste of resources. Our method requires no trust to other sensors, which is important to defend against the attack.
    Keywords: Wireless Sensor Networks, Random Key Pre-Distribution, Sybil Attack
  • Parisa Daneshjoo*, Hamid Haj Seyed Javadi, Hamid Reza Sharifi Pages 14-23
    Sink location is considered as a basic service in geographic routing in wireless sensor networks. Obtaining the location of sink node by source node using an efficient method with low complexity has always been a challenging issue in research. In this paper, a sink location algorithm based on Fano plane is proposed. The research challenge is how to ensure the intersection of two SLQ and SLA routes in at least one point. In the proposed solution, a compound Fano plane has been created in which both SLQ and SLA paths have a point of intersection. Source and destination nodes send data packets to nearby routes and the sensor node at the intersection announces the location of the destination node to the source. Simulation is used to evaluate the proposed algorithm. The results revealed reduction in communication overhead.
    Keywords: Combinatorial Scheme, Fano plane, Sink location, Wireless sensor network
  • Seyyedeh Faezeh Seyyedrezaei *, Gholamreza Dadashzadeh Pages 24-37
    A mathematical model is presented in the present study to controlý ýthe light propagation in an inhomogeneous mediaý. ýThe method is ýbased on the identification of the optimal materials distributioný ýin the media such that the trajectories of light rays follow theý ýdesired pathý. ýThe problem is formulated as a distributed parameter ýidentification problem and it is solved by a numerical methodý. ýTheý ýnecessary optimality conditions based on Karush-Kuhm-Tucker (KKT) conditions is derivedý ýby means of the adjoint approach and a solution algorithm isý ýintroduced to find local minimizers of the original problemý. ýTheý ýoriginal PDE and its corresponding adjoint are discretized by theý ýfinite difference method and they are solved efficiently by theý ýfast sweeping approachý. ýThe main benefits of the presentedý ýalgorithm is the computational efficiencyý, ýflexibility and abilityý ýto produce isotropic materials distribution with bounded physicalý ýpropertiesý. ýThe presented algorithm can be used for the optimalý ýdesign of waveguides and invisibility cloaks in the wavelength ýspectrum of visible lightý. ýThe feasibility of theý ýpresented method is studied by a numerical exampleý.
    Keywords: Adjoint method, Eikonal equation, Geometric optics, Metamaterial, Transformation optics
  • Yashar Zehforoosh, Tohid Sedghi Pages 38-49
    A newly designed printed slot antenna is presented that incorporates variable two band-notched functions for ultra-wideband (UWB) applications. The two band notches of this coplanar waveguide (CPW) fed antenna are achieved by an M-shaped slot (MSS) embedded in the radiating element and a C-shaped strip(CSS) close to ground plane, therefore two very narrow rejected properties in the wireless local area network (WLAN) band (5.15-5.825 GHz) and worldwide interoperability for microwave access (WiMAX) operation in the (3.3-3.7GHz) are obtained. The rectangular aperture is etched in the square ground plane. It has a determinative role in antenna’s impedance band width (IBW) enhancement, moreover, by adjusting carefully it leads to wide IBW. Based on simulated results it covers the frequency range 2.4–12.9 GHz with VSWR ≤ 2, which corresponds to a fractional bandwidth of 137% excluding the rejected bands. Numerical and experimental results are presented to understand its behavior. The volume of the proposed antenna is 25 × 25 × 0.8 mm3.
    Keywords: Slot antenna, ultra-wideband antenna, WLAN, WiMAX, band-notched function
  • Saeed Reza Ostadzadeh*, Hammid Samieean, Amin Mirzaie Pages 50-59
    In this paper, Intelligent water drop algorithm (IWD) is used to analyze single overhead line connected to grid-grounded arrester. In this approach, at first Norton’s equivalent circuit of the overhead line over lossy soil is computed by method of moments (MoM) and then for the problem under consideration, a nonlinear equivalent circuit in the frequency domain is proposed. Finally applying intelligent water drop algorithm (IWD), nonlinear analysis of the problem under consideration is efficiently analyzed and transient voltage across the arrester is easily computed. Comparison of the achieved voltage with transient solvers shows good agreement as well as fast run-time
    Keywords: IWD, arrester, lossy soil
  • Zohreh Rashki, Seyyed Javad Seyyed Mahdavi Chabok Pages 60-70
    In this paper, a new design of optical channel drop filter based on two- dimensional photonic crystal ring resonators with triangular lattice is proposed. The rods of this structure is silicon with the refractive index nsi=3.46 and the surrounding environment is air with the refractive index of nair=1.The widest photonic band gap obtains for the filling ratio of r/a = 0.2. The filter’s transmission spectrum is calculated using the two-dimensional (2D) finite-difference time-domain (2D-FDTD) numerical method. The simulation shows, 100% dropping efficiency and suitable quality factor at 1519.4 nm wavelength achieved for this filter. Also, in this paper, We investigate parameters which have an effect on resonant wavelength and transmission spectrum in this CDF, such as refractive index of inner rods and whole of dielectric rods of the structure. The overall size of the structure is small that is 14 μm × 14μm which is suitable for photonic integrated circuits (PIC) and optical communication network applications.
    Keywords: Photonic crystal, Ring resonator, Triangular lattice, Optical communication