A new hybrid model of dengue incidence rate using negative binomial generalised additive model and fuzzy c-means model: a case study in Selangor

Dengue is one of the top reason for illness and mortality in the world with beyond one­third of the world's population living in the risk areas of dengue infection. In this study, there are five stages to achieve the research objectives. Firstly, the verification of predetem1ined variables. Secondly, the identification of new datasets after clustered by district and Fuzzy C-Means Model (FCM). Thirdly, the development of models using the existing dataset and the new datasets which clustered by the two different clustering categories. Then, to assess the models developed by using three measurement methods which are deviance (D), Akaike Jnfonnation Criteria (AIC) and Bayesian Infonnation Criteria (BIC} Lastly, the validation of model developed by comparing the value of D, AIC and BIC between the existing model and the new models developed which used the new datasets. There are two different clustering techniques applied which are clustering the data by district and by FCM. This study proposed a new modelling hybrid framework by using two statistical models which are FCM and negative binomial Generalised Additive Model (GAM). This study successfully presents the significant difference in the climatic and non-climatic factors that influenced dengue incidence rate (DIR) in Selangor, Malaysia. Results show that the climatic factors such as rainfall with current month up to 3 months and number of rainy days with current month up to lag 3 months are significant to DIR. Besides, the interaction between rainfall and number of rainy days also shows strong positive relationship to DIR. Meanwhile, non-climatic vaiiables such as population density, number of locality and lag DIR from I month until 3 months also show significant relationship towards DIR For both clustering techniques, there are two clusters fonned and there are four new models developed in this study. After comparing the values of D, AIC ai1d BIC between the existing model and the new models, this study concluded that four new models recorded lower values compared to the existing model. Therefore, the four new models are selected to present the dengue incidence in Selangor

Pre-kompensasi Respon Saluran Transmisi pada Jaringan Akses Multimedia ADSL 1,6 Mbps

Sari. Berkembangnya pola kehidupan masyarakat semakin meningkatkan kebutuhan akan layanan yang mudah dan cepat, seperti jaringan akses multimedia. Salah satu kelompok sistem xDSL yang merupakan teknologi jaringan akses alternative adalah 16-QAM-ADSL. Masalah utama yang dihadapi dalam sistem Xdsl adalah memperkecil pengaruh respons saluran transmisi, yang umumnya dapat menggunakan equalizer. Pre-kompensasi respons saluran transmisi dapat ditambahkan untuk membantu kerja equalizer. Pre-kompensasi adalah sebuah filter yang ditambahkan sebuah ADC untuk kompensasi awal respons saluran transmisi. Penggunaan pre-kompensasi dapat memperpendek panjang koefisien equalizer menjadi sekitar 20 tap, yang apabila tanpa pre-kompensasi memerlukan sampai 100 tap. 16-QAM-ADSL dapat mencapai kapasitas 1,6 Mbps (TI/DSI pada 1,544 Mbps) pada saluran sejauh 18 kft. 26 AWG. Sistem transceiver 16-QAM-ADSL yang diteliti di sini dapat bekerja dengan baik setelah melakukan pelatihan selama 0,25 detik. Kesalahan fasa sampling sekitar 7,2 derajat dan frekuensi sampling sekitar 10kHz. Transmission Channel of Pre-compensation Response in the ADSL 1.6M bps Multimedia Access NetworkAbstract. The development of the living pattern of society has increased the needs of faster and easier services, such as multimedia access network. One of the xDSL family, as an alternative to the network access technology, is the 16-QAM ADSL. The main problem in xDSL is reducing the transmission channel response which usually can be accomplished by using an equalizer. Transmission channel of pre-compensation response can be added to assist the work of the equalizer. A pre-compensation is a filter which has been added before ADC to compensate the earlier response of the transmission channel. The utilization of the pre-compensation can reduce the length of the equalizer coefficients from 100 tap to 20 tap. The 16-QAM ADSL can reach the capacity of 1.6M bps (TI/DSI 1.544Mbps) in a 18 kft channel 26 AWG. The 16-QAM ADSL transceiver system which is explored in this study has worked well after 0.25 second training period. The sampling phase error is about 7.2° and the sampling frequency error is about 10 Khz

Development of a dc-ac power conditioner for wind generator by using neural network

This project present of development single phase DC-AC converter for wind generator application. The mathematical model of the wind generator and Artificial Neural Network control for DC-AC converter is derived. The controller is designed to stabilize the output voltage of DC-AC converter. To verify the effectiveness of the proposal controller, both simulation and experimental are developed. The simulation and experimental result show that the amplitude of output voltage of the DC-AC converter can be controlled

Cost effective DSL solutions for the developing countries.

Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Westville, 2004.Developing countries in Africa present a graphic picture of the digital divide. High costs associated with serving rural customers are the major cause of uneven distribution of services. Rural areas are characterised by a high rate of unemployment and a poor level of education. This results in a scenario where most of the residents are unable to utilize IT resources. Some people in these areas are not informed about the availability and importance of these technologies in the market. Those who are academically fit for accessing these technologies often cannot afford them. Some of the areas still have no existing telecommunications infrastructure. High deployment costs associated with broadband services makes it even more challenging to deploy such services in this environment. In Africa approximately 80% of the population is living in rural areas, which alone creates a demand for the coverage of rural regions. Leaving such a large number of residents not connected, means poor medical care, students cannot participate in distance learning programs which means poor quality of education, poor performance in businesses, poor farming and crippling delivery of government services. DSL technologies were originally designed to suit suburban to urban conditions. In this research it is shown that broadband services can be delivered to rural people by applying DSL technologies, using the existing telecommunications infrastructure. This will mean significant savings, as it does not need core network investments. DSL increases network capacity to a network, which is no longer limited to voice. With this technology a number different high bandwidth applications are delivered to the homes, schools, hospitals, telecentres and small businesses. The cost effectiveness of these technologies for several reach and rural traffic environment is investigated. This is done by investigating several promising DSL solutions in terms of diverse geography, demographics and other cost dictating parameters

Analysis of the impact of impulse noise in digital subscriber line systems

In recent years, Digital subscriber line (DSL) technology has been gaining popularity as a high speed network access technology, capable of the delivery of multimedia services. A major impairment for DSL is impulse noise in the telephone line. However, evaluating the data errors caused by this noise is not trivial due to its complex statistical nature, which until recently had not been well understood, and the complicated error mitigation and framing techniques used in DSL systems. This thesis presents a novel analysis of the impact of impulse noise and the DSL framing parameters on transmission errors, building on a recently proposed impulse noise model. It focuses on errors at higher protocol layers, such as asynchronous transfer mode (ATM), in the most widely used DSL version, namely Asymmetric DSL (ADSL). The impulse noise is characterised statistically through its amplitudes, duration, inter-arrival times, and frequency spectrum, using the British Telecom / University of Edinburgh / Deutsche Telekom (BT/UE/DT) model. This model is broadband, considers both the time and the frequency domains, and accounts for the impulse clustering. It is based on recent measurements in two different telephone networks (the UK and Germany) and therefore is the most complete model available to date and suited for DSL analysis. A new statistical analysis of impulse noise spectra from DT measurements shows that impulse spectra can be modelled with three spectral components with similar bandwidth statistical distributions. Also, a novel distribution of the impulse powers is derived from the impulse amplitude statistics. The performance of a generic ADSL modem is investigated in an impulse noise and crosstalk environment for different bit rates and framing parameters. ATM cell and ADSL frame error rates, and subjective MPEG2 video quality are used as performance metrics. A new modification of a bit loading algorithm is developed to enable stable convergence of the algorithm with trellis coding and restricted subtone constellation size. It is shown that while interleaving brings improvement if set at its maximum depth, at intermediate depths it actually worsens the performance of all considered metrics in comparison with no interleaving. No such performance degradation is caused by combining several symbols in a forward error correction (FEC) codeword, but this burst error mitigation technique is only viable at low bit rates. Performance improvement can also be achieved by increasing the strength of FEC, especially if combined with interleaving. In contrast, trellis coding is ineffective against the long impulse noise error bursts. Alien as opposed to kindred crosstalk degrades the error rates and this is an important issue in an unbundled network environment. It is also argued that error free data units is a better performance measure from a user perspective than the commonly used error free seconds. The impact of impulse noise on the errors in DSL systems has also been considered analytically. A new Bernoulli-Weibull impulse noise model at symbol level is proposed and it is shown that other models which assume Gaussian distributed impulse amplitudes or Rayleigh distributed impulse powers give overly optimistic error estimates in DSL systems. A novel bivariate extension of the Weibull impulse amplitudes is introduced to enable the analysis of orthogonal signals. Since an exact closed-form expression for the symbol error probability of multi-carrierQAM assuming Bernoulli-Weibull noise model does not exist, this problem has been solved numerically. Multi-carrier QAM is shown to perform better at high signal-to-noise ratio (SNR), but worse at low SNR than single carrier QAM, in both cases because of the spreading of noise power between subcarriers. Analytical expressions for errors up to frame level in the specific case of ADSL are then derived from the impulse noise model, with good agreement with simulation results. The Bernoulli-Weibull model is applied to study the errors in single-pair highspeed DSL (SHDSL). The performance of ADSL is found to be better when the burst error mitigation techniques are used, but SHDSL has advantages if low bit error rate and low latency are required

High Dimensional Modulation and MIMO Techniques for Access Networks

Exploration of advanced modulation formats and multiplexing techniques for next generation optical access networks are of interest as promising solutions for delivering multiple services to end-users. This thesis addresses this from two different angles: high dimensionality carrierless amplitudephase (CAP) and multiple-input multiple-output (MIMO) radio-over-fiber (RoF) systems. High dimensionality CAP modulation has been investigated in optical fiber systems. In this project we conducted the first experimental demonstration of 3 and 4 dimensional CAP with bit rates up to 10 Gb/s. These results indicate the potentiality of supporting multiple users with converged services. At the same time, orthogonal division multiple access (ODMA) systems for multiple possible dimensions of CAP modulation has been demonstrated for user and service allocation in wavelength division multiplexing (WDM) optical access network. 2 x 2 MIMO RoF employing orthogonal frequency division multiplexing (OFDM) with 5.6 GHz RoF signaling over all-vertical cavity surface emitting lasers (VCSEL) WDM passive optical networks (PONs). We have employed polarization division multiplexing (PDM) to further increase the capacity per wavelength of the femto-cell network. Bit rate up to 1.59 Gbps with fiber-wireless transmission over 1 m air distance is demonstrated. The results presented in this thesis demonstrate the feasibility of high dimensionality CAP in increasing the number of dimensions and their potentially to be utilized for multiple service allocation to different users. MIMO multiplexing techniques with OFDM provides the scalability in increasing spectral effciency and bit rates for RoF systems. High dimensional CAP and MIMO multiplexing techniques are two promising solutions for supporting wired and hybrid wired-wireless access networks

Loading Algorithms for Adaptive SS-MC-MA Systems over Wireline Channels: Comparison with DMT

In this paper, we propose to combine adaptive loading principles with the spread-spectrum multicarrier multiple access (SS-MC-MA) scheme. Such an approach has particular interests in the context of powerline communications (PLC), where the transmitter has not only to exploit robust transmission techniques, but has also to adapt the waveform to the channel response. We introduce finite-granularity loading algorithms that dynamically handle the configuration of the system under power spectral density constraints. The presented algorithms assign subcarriers, spreading codes, bits and energy to each user in order to maximize either the data rate or the noise margin at a given target symbol error rate. These algorithms can actually be viewed as a widening of the classical waterfilling approach in the case of an hybrid spread-spectrum multicarrier system. Simulation results of the new scheme are presented for different measured PLC channels and are compared with those of the classical discrete multitone modulation (DMT) approach. It is shown that the adaptive SS-MC-MA scheme performs significantly better than DMT, due to its natural energy gathering capability. Adaptive SS-MC-MA then leads to a more efficient bits and energies distribution and constitutes a simple solution to reduce the quantification loss induced by the use of finite order modulation

FFT and FIR Filter implementations for the DSL MODEMS

Broad band digital communication that operates over a standard copper wires. It requires the DSL modems which splits the transmissions into 2 frequency bands. The lower frequencies for voice and the higher frequencies for digital data (internet) in order to transmit the data to larger distances through a copper cable we need modulation techniques. Generally in this DSL modems modulation used is QAM technique. The output of the QAM is complex data this complex data we cannot transfer directly through a copper cable because the data should be in time domain or otherwise the phase of the data which is in frequency domain can be lost, in copper cable so this data should be converted in time domain by using IDFT technique. As IDFT requires more number of complex multiplications and more number of complex additions in comparison to IFFT so to reduce the additions and multiplications IFFT technique is used. At the receiver side we can retrieve the same data by using FFT technique. In this section the implemented FFT architecture is fully efficient and this architecture will require less area. And before we have to transmit through the copper line we have to do interpolation or decimation by using the Filtering operation. The implemented poly phase architecture for the filtering is fully efficient, symmetrical and it requires less number of multipliers

Physical Layer Techniques for High Frequency Wireline Broadband Systems

This thesis collects contributions to wireline and wireless communication systems with an emphasis on multiuser and multicarrier physical layer technology. To deliver increased capacity, modern wireline access systems such as G.fast extend the signal bandwidth up from tens to hundreds of MHz. This ambitious development revealed a number of unforeseen hurdles such as the impact of impedance changes in various forms. Impedance changes have a strong effect on the performance of multi-user crosstalk mitigation techniques such as vectoring. The first part of the thesis presents papers covering the identification of one of these problems, a model describing why it occurs and a method to mitigate its effects, improving line stability for G.fast systems.A second part of the thesis deals with the effects of temperature changes on wireline channels. When a vectored (MIMO) wireline system is initialized, channel estimates need to be obtained. This thesis presents contributions on the feasibility of re-using channel coefficients to speed up the vectoring startup procedures, even after the correct coefficients have changed, e.g., due to temperature changes. We also present extensive measurement results showing the effects of temperature changes on copper channels using a temperature chamber and British cables. The last part of the thesis presents three papers on the convergence of physical layer technologies, more specifically the deployment of OFDM-based radio systems using twisted pairs in different ways. In one proposed scenario, the idea of using the access copper lines to deploy small cells inside users' homes is explored. The feasibility of the concept, the design of radio-heads and a practical scheme for crosstalk mitigation are presented in three contributions