217 research outputs found

    Genetic Algorithm Assisted Error Probability Optimisation for Beamforming

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    A novel Genetic Algorithm (GA) assisted direct error probability optimisation technique is proposed for adaptive beamforming, which reduces the achievable error probability by nearly two orders of magnitude at a signal-to-noise ratio of 10dB in the investigated scenario in comparison to the minimum mean-squared error beamforming benchmarker

    Smart Beamforming for Wireless Communications: A Novel Minimum Bit Error Rate Approach

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    Spatial processing with adaptive antenna array has shown real promise for substantial capacity enhancement in wireless communications. We propose a novel beamforming technique based on the minimum bit error rate (MBER) criterion. It is demonstrated that the MBER approach utilizes the system resource, the antenna elements, more intelligently than the standard minimum mean square error (MMSE) approach. Consequently, the MBER beamforming can provide significant performance gain in terms of smaller bit error rate (BER) over the MMSE beamforming

    Backtracking Search Optimization for Collaborative Beamforming in Wireless Sensor Networks

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    Due to energy limitation and constraint in communication capabilities, the undesirable high battery power consumption has become one of the major issues in wireless sensor network (WSN). Therefore, a collaborative beamforming (CB) method was introduced with the aim to improve the radiation beampattern in order to compensate the power consumption. A CB is a technique which can increase the sensor node gain and performance by aiming at the desired objectives through intelligent capabilities. The sensor nodes were located randomly in WSN environment. The nodes were designed to cooperate among each other and act as a collaborative antenna array. The configuration of the collaborative nodes was modeled in circular array formation. The position of array nodes was determined by obtaining the optimum parameters pertaining to the antenna array which implemented by using Backtracking Search Optimization Algorithm (BSA). The parameter considered in the project was the side-lobe level minimization. It was observed that, the suppression of side-lobe level for BSA was better compared to the radiation beampattern obtained for conventional uniform circular array

    Adaptive Minimum Bit Error Rate Beamforming Assisted Receiver for QPSK Wireless Communication

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    This paper considers interference limited communication systems where the desired user and interfering users are symbol-synchronized. A novel adaptive beamforming technique is proposed for quadrature phase shift keying (QPSK) receiver based directly on minimizing the bit error rate. It is demonstrated that the proposed minimum bit error rate (MBER) approach utilizes the system resource (antenna array elements) more intelligently, than the standard minimum mean square error (MMSE) approach. Consequently, an MBER beamforming assisted receiver is capable of providing significant performance gains in terms of a reduced bit error rate over an MMSE beamforming one. A block-data based adaptive implementation of the theoretical MBER beamforming solution is developed based on the classical Parzen window estimate of probability density function. Furthermore, a sample-by-sample adaptive implementation is also considered, and a stochastic gradient algorithm, called the least bit error rate, is derived for the beamforming assisted QPSK receiver

    Fundamental Shape Discrimination of Underground Metal Object Through One-Axis Ground Penetrating Radar (GPR) Scan

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    Ground Penetrating Radar (GPR) was used in this research to detect or recognize the buried objects underground. Hyperbolic signals formed by datagram of GPR after detection the buried objects which quite similar to each other in term of metal shapes. The research was tested on the metal cube and metal cylinder by using the A-scan of GPR. There are steps in this signal processing step which are pre-processing step, feature extraction, and classification process. The segmentation process hyperbolic signals were segmented one by one and normalize from the negative to positive signals. The hyperbole from the metal cylinder and metal cube that had been buried in the ground is differentiated using four features of their respective A-scans which are found the maximum value of amplitude signal graph, the number of peaks in the signals graph, skewness, and standard deviation values. Finally, the classification process used learning algorithm of Multi-Layer Perceptron (MLP) was a test on Bayesian Regulation Backpropagation (BR) was given the highest accuracy, 98.70% as a classifier to classify the metal shapes which are a metal cube and metal cylinder

    Genetic algorithm assisted error probability optimisation for beamforming

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    External attacks on automotive system through wireless communication channels

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    The reliance of today’s automotive system on electronics control system is expected to make the cars to be state-of-the-art vehicle. However, this technology dependency results in the cars to be exposed to attacks by the hacker through the manipulation of electronics system. Previously, for the attacker to compromise car’s system, he/she must access the car directly and internally. However, with the incorporation of wireless technologies such as Bluetooth and cellular into automotive system for example in its telematic units, the attacks are evolved from internal attacks into remote attack where the adversary does not have to internally access the car’s system. This paper analyses the vulnerabilities of the automotive system by the remote attacks performed through Bluetooth and cellular. Once the vulnerabilities were analyzed, the threats imposed by these vulnerabilities are accessed. Two scenarios namely theft and surveillance are used to exemplify the threats that are carried by the vulnerability of the automotive system to the remote attacks. From the vulnerability analysis and threat assessment, it can be deduced that the automotive system is vulnerable to attacks and proper countermeasure must be taken to curb the implication from the attacks.Keywords: Hardware Trojan, Insertion, Third-part IP, Trus

    Design of an automatic solar lighting system

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    Today, the worldwide research trends are heading towards producing environmental friendly outcomes. Thus, today the electricity is mostly generated from renewable sources such as sunlight, wind, tides and other to reduce dependency on non-renewable sources like hydroelectrics, fossil fuels and others. This paper presents an innovation of the automatic lighting system with the solar as a source of the system. Charger controller circuit is necessary to cut off the current of the rechargeable battery when reaching its maximum voltage. Dark-on relay circuit functions as an automatic switch to the light so that the light will be automatically turned on when there is no light or at night. Otherwise, the light will be turned off. The system can be applied to the room light, outdoor light, corridor light, spotlight or streetlight. The system is low cost and beneficial for home usage to save electricity bills and when the occupants are absent for relatively long period of time.Keywords: renewable energy; solar energy; green technology; sustainable; dark on relay; automatic lighting system; analog electronic circuits; LD

    PT-symmetric Solutions of Schrodinger Equation with position-dependent mass via Point Canonical Transformation

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    PT-symmetric solutions of Schrodinger equation are obtained for the Scarf and generalized harmonic oscillator potentials with the position-dependent mass. A general point canonical transformation is applied by using a free parameter. Three different forms of mass distributions are used. A set of the energy eigenvalues of the bound states and corresponding wave functions for target potentials are obtained as a function of the free parameter.Comment: 13 page

    N-body simulations of gravitational dynamics

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    We describe the astrophysical and numerical basis of N-body simulations, both of collisional stellar systems (dense star clusters and galactic centres) and collisionless stellar dynamics (galaxies and large-scale structure). We explain and discuss the state-of-the-art algorithms used for these quite different regimes, attempt to give a fair critique, and point out possible directions of future improvement and development. We briefly touch upon the history of N-body simulations and their most important results.Comment: invited review (28 pages), to appear in European Physics Journal Plu
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