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Table of Contents
Automotive Thermal Comfort Control - A Blackbox Approach
Effect of Distance on the Accuracy of RSS-Based Geometric Positioning Methods
Rainfall Drop-Size Estimators for Weibull Probability Distribution using Method of Moments Technique
A Multi-Dimensional Code-Division-Multiplexed OFDMA Modem Using Cyclic Rotated Orthogonal Complete Complementary Codes
Automotive Thermal Comfort Control - A Blackbox Approach by J. Kranz, T.I. van Niekerk, H.F.G. Holdack-Janssen and G. Gruhler
Abstract: Thermal comfort is a very vague and a very individual term, which depends on physiological and psychological variables. Thermal comfort in transient environments, like an automotive cabin, is far from understood and general accepted theories do not yet exist. This paper investigates the concept of using a black-box approach for directly associating thermal comfort to field measurements. Artificial intelligence is used to predict blower level, air blend position and incabin temperature for a given environment. The results are promising and it is concluded that methods of artificial intelligence can be used as a powerful tool during the development process of vehicle HVAC control units and have great potential to reduce development time and costs.
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Effect of Distance on the Accuracy of RSS-Based Geometric Positioning Methods by F.M. Dahunsi, B. Dwolatzky and A. Love
Abstract: The accuracy of Received Signal Strength (RSS)-based positioning methods is highly variable due to its dependence on various varying parameters such as the wireless environment, topology of the network, propagation model utilized etc. In this paper, drive test data were analyzed to examine the effect of distances from the Mobile Station to the serving and neighbouring base stations (BSs) on the accuracy of four RSS-based geometric positioning methods. The relationship between the accuracy of these positioning methods and distances between the BSs were also considered. There is relatively varying differences that the topologies of the network have on the accuracy of the positioning algorithms. The RSS-based geometric algorithms considered include the Centre of Gravity, the Circular Trilateration, Circular Trilateration and the Least Square algorithms.
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Rainfall Drop-Size Estimators for Weibull Probability Distribution using Method of Moments Technique by A. Alonge and T. Afullo
Abstract: This paper proposes a new approach for deriving the input estimators for the Weibull probability rain drop-size distribution (DSD) using the Method of Moments (MM). The Stirling’s approximation is used to estimate the gamma function which is part of the raw moment function of the Weibull probability distribution. The parameters No, η and β are estimated using a comparative analysis with the likely measured moments of a statistical data. The new parameters are then tested with collected data at Durban, South Africa by using least squares regression fitting technique to derive their power-law relationships with rainfall rate. The results show that the proposed Weibull distribution fits well with the measured data at tested rainfall rates. In comparison with the ITU-R P. 838-3, the average RMSE of its specific attenuation is 0.99 for horizontal polarization and 1.40 for vertical polarization at selected rainfall rates for a frequency range of 0 to 100 GHz.
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A Multi-Dimensional Code-Division-Multiplexed OFDMA Modem Using Cyclic Rotated Orthogonal Complete Complementary Codes by A.M. Merensky, J.H. van Wyk and L.P. Linde
Abstract: In this paper we present a novel multiple access scheme based on a combination of multi-carrier OFDMA techniques and a multi-dimensional spread spectrum modem that makes use of rotated mutually orthogonal complete complementary codes. A multi-dimensional code-division multiple access (MD-CDMA) modem with recent designs of perfectly orthogonal complete complementary codes, produces an innovative modulation technique, which is further improved upon by exploiting the rotational properties of the spreading codes to increase the throughput and spectral efficiency. The system is extended by making use of multiple carrier frequencies as in orthogonal frequency-division multiple access (OFDMA), providing additional benefits such as diversity by being able to spread the data in frequency and/or in time. The proposed modem offers multiple access interference (MAI)-free operation due to the perfect autocorrelation and zero cross-correlation properties of the spreading codes. The uniquely proposed modulation technique together with the integration of rotated complete complementary codes, produces a system with better spectral efficiency compared to a theoretical non-spread system, with high data throughput rates, better noise tolerances in harsh channel conditions and an increased user capacity. Various other benefits such as low complex channel estimation and synchronisation, rate adaption, and resistance to the near-far problem can be attributed to the system..
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