Interference Suppression Performance of Automotive UWB Radars Using Pseudo Random Sequences

Ultra wideband (UWB) automotive radars have attracted attention from the viewpoint of reducing traffic accidents. The performance of automotive radars may be degraded by interference from nearby radars using the same frequency. In this study, a scenario where two cars pass each other on a road was considered. Considering the utilization of cross-polarization, the desired-to-undesired signal power ratio (DUR) was found to vary approximately from -10 to 30 dB. Different pseudo random sequences were employed for spectrum spreading the different radar signals to mitigate the interference effects. This paper evaluates the interference suppression provided by maximum length sequence (MLS) and Gold sequence (GS) through numerical simulations of the radar’s performance in terms of probability of false alarm and probability of detection. It was found that MLS and GS yielded nearly the same performance when the DUR is -10 dB (worst case); for example when fixing the probability of false alarm to 0.0001, the probabilities of detection were 0.964 and 0.946 respectively. The GS are more advantageous than MLS due to larger number of different sequences having the same length in GS than in MLS

Multi-Layer Perceptron (MLP)-Based Nonlinear Auto-Regressive with Exogenous Inputs (NARX) Stock Forecasting Model

The prediction of stocks in the stock market is important in investment as it would help the investor to time buy and sell transactions to maximize profits. In this paper, a Multi-Layer Perceptron (MLP)-based Nonlinear Auto-Regressive with Exogenous Inputs (NARX) model was used to predict the prices of the Apple Inc. weekly stock prices over a time horizon of 1995 to 2013. The NARX model belongs is a system identification model that constructs a mathematical model from the dynamic input/output readings of the system, and predicts the future behaviour of the system based on the constructed mathematical model. The One Step Ahead (OSA) and correlation tests were used to test validate the model. Results demonstrate the predictive ability of the model while producing Gaussian residuals (indicating the validity of the model)

Dual-Band Bandpass Filter with Dumbbell Shaped Defective Ground Structure

A dumbbell shaped defective ground structure (DGS) is implemented to improve the performance of an existing dual-band bandpass filter topology. The filter design is based on parallel-coupled lines connected to matched transmission lines. Various positions and dimensions of dumbbell DGSs are implemented and their effects on the filter performance are investigated. It is found that the utilisation of dumbbell shaped DGSs in this topology improve the steepness of the responses for the first and second passbands with centre frequencies of 1.365 and 2.932 GHz respectively. The optimised dimensions of the DGS are 5 x 5 mm2 for both its rectangular slots connected by a 0.5 mm narrow slot width. The optimised positions of the DGSs are located at the centre and the edges of the parallel-coupled lines. The simulated and measured results of the filter are analysed and discussed in this paper

Classification of Brainwave Asymmetry Influenced by Mobile Phone Radiofrequency Emission

AbstractA discriminant classification of human brainwave signals influenced by mobile phone radiofrequency (RF) emission is proposed in this paper. Brainwave signals were recorded using electroencephalograph (EEG) focusing on the alpha sub-band with frequency range from 8 to 12Hz. The EEG test was divided into 3 sessions; Before, During and After with 5minutes duration for each session. Analysis involved 95 participants from engineering students. The students were grouped into 3 groups according to the side of exposure; Left Exposure (LE), Right Exposure (RE) and Sham Exposure (SE). This work suggested that RF emit by the mobile phone give several effects to brainwave signals and there are significant different between the session of exposure. As result, the highest classification rate as high as 94.7% is achieved in session During

Target Localization in MIMO OFDM Radars Adopting Adaptive Power Allocation among Selected Sub-Carriers

Multiple-input multiple-output (MIMO) radar has been introduced to enhance the performance of classical radar systems. Nevertheless, radar cross sections (RCS) fluctuations remains a known problem in radars. Target localization using narrowband signal produces reduced accuracy due to RCS fluctuations. One of the solution to this problem is utilization of frequency diversity of wideband signal. This paper presents target localization in MIMO radars using an adaptive orthogonal frequency division multiplexing (OFDM) waveform for effective frequency diversity utilization. Each transmitting antenna transmits an OFDM signal in different time slots and received by the each receiving antenna in the receiver array. A joint direction-of-departure (DOD) and direction-of-arrival (DOA) estimation scheme is applied to each of the OFDM sub-carrier using two-way multiple signal classification (MUSIC) algorithm. The estimation results at each sub-carrier are combined based on majority decision using angle histogram (non-parametric approach) to formulate the final wideband angle estimation. In addition, an adaptive power allocation among the sub-carriers is implemented, where the system evaluates the signal quality at each sub-carrier and consequently formulates a feedback to the MIMO transmitting side. The following transmission will comprise of OFDM waveform that focuses the transmit power at selected sub-carriers only. The sub-carrier selection is based on singular values obtained from singular value decomposition operation at each of the sub-carrier. The performance of the proposed scheme is evaluated through numerical simulations as well as validation by experiments in a radio anechoic chamber. It was demonstrated that the usage of larger number of sub-carriers improves the angle estimation accuracy

Design of Serial-Fed Bend-Array and Measured Results

For the next generation mobile system (5G), a cylindrical lens antenna is developed for mobile base station application. As for the feed radiator for this lens antenna, bendarray configuration that produces a bifurcated beam is also developed. The bend-array configuration consisting of four rectangular patch array elements with serial feed network. In previous work, achievement of the bifurcated beam by bendarray configuration was shown by electromagnetic simulations. In this paper, a practical bend-array composed of four numbers of patch elements is fabricated. To verify the radiation characteristics, measured results of antenna input characteristic and radiation pattern are compared with the designed results. Through good agreement of measured and designed results, achievement of practical antenna is ensured

Purge Material Berbasis Campuran Recycled HDPE dan Lempung Kaolin untuk Ekstrusi Polipropilena dan Masterbatch

Extruder (sistem screw/barel) telah menjadi alat yang sangat penting dalam pengolahan produk akhir plastik. Proses pembersihan residu dalam barel extruder dengan memasukkan bahan pembersih (purge material) tanpa membongkar mesin disebut purging extruder. Penelitian ini bertujuan untuk mengetahui pengaruh lempung kaolin pada variasi 0, 3, 6, dan 9% dalam bahan pembersih recycled high density polyethylene (HDPE) terhadap warna dan gugus fungsi ekstrudat. Hasil uji warna menunjukkan bahwa seiring penambahan lempung kaolin, warna ekstrudat bahan pembersih semakin bersih dari kontaminasi warna primer PP/masterbatch. Jumlah optimum penambahan lempung kaolin adalah 6% dengan kandungan masterbatch lebih rendah dibandingkan variasi lainnya karena diperoleh kontaminasi warna dan kandungan gugus fungsi residu yang rendah pada ekstrudatnya

Purge Material Berbasis Campuran Recycled HDPE dan Lempung Kaolin untuk Ekstrusi Polipropilena dan Masterbatch

Extruder (sistem screw/barel) telah menjadi alat yang sangat penting dalam pengolahan produk akhir plastik. Proses pembersihan residu dalam barel extruder dengan memasukkan bahan pembersih (purge material) tanpa membongkar mesin disebut purging extruder. Penelitian ini bertujuan untuk mengetahui pengaruh lempung kaolin pada variasi 0, 3, 6, dan 9% dalam bahan pembersih recycled high density polyethylene (HDPE) terhadap warna dan gugus fungsi ekstrudat. Hasil uji warna menunjukkan bahwa seiring penambahan lempung kaolin, warna ekstrudat bahan pembersih semakin bersih dari kontaminasi warna primer PP/masterbatch. Jumlah optimum penambahan lempung kaolin adalah 6% dengan kandungan masterbatch lebih rendah dibandingkan variasi lainnya karena diperoleh kontaminasi warna dan kandungan gugus fungsi residu yang rendah pada ekstrudatnya