WA Clarke

Calebyte

It is very critical for solar racers to achieve real time tracking of their solar vehicle during any race. The system is made of real time visualisation of the video feedback of the car from the escort vehicle, the location of the car on the maps as it is racing and its velocity. The real time video feedback of the race could be retrieved from the...

In this paper, we present and investigate the performance of an algorithm designed to identify facial features on an android mobile platform. Facial feature identification is the necessary step before many computer vision systems including emotion detection, face tracking and face recognition. The facial feature identification algorithm presented i...

An object tracking algorithm using the Mean Shift framework is presented which is largely invariant to both partial and full occlusions, complex backgrounds and change in scale. Multiple features are used to gain a descriptive representation of the target object. Image moments are used to determine the scale of the target object. A kalman filter is...

One of the main aims of telecommunication subsidies in developing countries is to extend the information and communication services to the information "have nots" through subsidized communication services. However, subsidies may have an impact on network resource utilization, quality of service and the amount of revenue generated. For example, subs...

A novel method for estimating the variance and standard deviation of the additive white Gaussian noise contained in an image will be presented. Only a single image is used to estimate the noise properties. Local image outliers are discarded, this allows us to separate the additive zero mean white Gaussian noise contained in a noisy image from the o...

In this paper we analyse the impact of a reality TV show on the participating engineering students through a qualitative case study. The reality TV show depicted an in-house engineering student competition through the constructing of alternative fuel-sourced vehicles for participation in the biannual international Solar Challenge competition. The r...

In this paper we present the key learning points from a publicly broadcasted reality TV show produced by the Faculty of Engineering and the Built Environment at the University of Johannesburg. This reality TV show was based on a preliminary development for the university's entry in the 2012 South African leg of the Solar Challenge. It featured unde...

In this paper we describe the development of a unique undergraduate engineering research program that has been run for two years. It has focussed on the proposition that undergraduate students if properly trained and adequately mentored can produce publishable results while still at the undergraduate level. The aims, curriculum development and prel...

In this paper we consider engineering education as a process that has over many years developed a particular ethical and philosophical framework. These ethical and philosophical frameworks are often dormant and unquestioned. During the development of an innovative reality TV mediated engineering design and test project (the Fuelduel1 project) for u...

The process of developing a publication guide titled “How to write your first academic paper” was presented in this paper. A detailed qualitative approach was followed to extract key elements from transaction and conference papers that appeared in the IEEE Transactions of Information Theory during the past decade. The approach taken was to learn fr...

A proof that the Helberg code is capable of correcting multiple deletion/insertion errors is presented. This code is a generalization of the number-theoretic Levenshtein code which is capable of correcting a single deletion/insertion. However, apart from exhaustive testing of short codes, no proof was hitherto given to verify that the Helberg code...

A code construction is proposed to add a multiple insertion/deletion error correcting capability to a run-length limited sequence. The codewords of this code are themselves run-length limited. The insertion/deletion correcting capability is achieved by requiring several weighted sums of run-lengths in the codewords to satisfy certain congruences mo...

Organic bistable memory device was fabricated by spin coating of polymethyl methacrylate (PMMA):ZnO nanoparticles onto ITO coated glass. The thin films were characterized by Raman, SEM, AFM and FTIR spectroscopies. The electrical characterization showed that the two-terminal device exhibited excellent switching characteristics with ON/OFF ratio gre...

The aim of this paper is to document the process of developing a usable publication guide to support students to publish their first academic paper. Academic publishing is obviously a wide and complex field, taking many years to master. The intention was therefore not to develop students to “expert” level in a single event, but rather to get studen...

The dimensions of an antenna system defines its performance. This implies proper calibration and fabrication process are vital. Thus, there is a need to investigate the influence of the variations in the dimensions of the antenna on its performance. A switched parasitic array antenna is modelled in MATLAB. The variations in the antenna dimensions:...

The dimensions of an antenna system defines its performance. This implies proper calibration and fabrication process are vital. Thus, there is a need to investigate the influence of the variations in the dimensions of the antenna on its performance. A switched parasitic array antenna is modelled in MATLAB. The variations in the antenna dimensions:...

Natural fibers are emerging as low cost, lightweight and apparently environmentally superior alternatives to glass fibers in composites. With the increasing importance of environmental interactions, several innovations of the environmental performance are introduced in automotive industry. One aspect of innovation is an environmental material selec...

In the present study, a microcontroller based system for the measurement of blood pressure is designed and developed. It is based on the oscillometric method. A microcontroller MCF51QE128 is used in the present study. Further, an LCD module to display the data of systolic and diastolic blood pressure and MR2A16A asynchronous magneto resistive RAM t...

Natural fibers are emerging as low cost, lightweight and apparently environmentally superior alternatives to glass fibers in composites. With the increasing importance of environmental interactions, several innovations of the environmental performance are introduced in automotive industry. One aspect of innovation is an environmental material selec...

Capacitance measurement with integrated instruments (function generator & Digital multimeter) has been designed and developed. The unknown capacitance is measured by measuring the voltage across capacitor in RC network. The Digital Synthesis Arbitrary Function Generator/Counter (Protek 9305), and Dual Display Multimeter (Escort 3146A) are used as p...

In this paper we present a method of electronic beam steering for circular switched parasitic array (SPA) antennas. In circular SPA antennas, one achieves azimuth beam steering by open-circuiting and short-circuiting different parasitic elements, usually with only one parasitic element open-circuited at a time. For the SPA antenna with few parasiti...

We propose the construction of a non-binary multiple insertion/deletion correcting code based on a binary multiple insertion/deletion correcting code. In essence, it is a generalisation of Tenengol'ts' non-binary single insertion/deletion correcting code. We evaluate the cardinality of the proposed construction based on the asymptotic upper bound o...

Influences of variations in the structural parameters (or antenna dimensions) of the five elements circular switched parasitic array (SPA) antenna at 2.4 GHz are investigated in this paper. Variations in the structural parameters are assumed to model random errors in such parameters. The effects of these variations on the performance of the SPA ant...

Pricing is an important feature in preventing the misuse of any resource (specifically public resources) in a telecommunication network. The free-rider, tragedy of the anti-commons and tragedy of the commons problems can arise in the provision of public resources, when users of the resource have to contribute towards the cost of production. Selfish...

CCTV systems are frequently monitored manually by a human observer. This human observer is typically responsible for dealing with tens or hundreds of cameras at a time. Potential security threats may easily be missed by the system's human operators due to fatigue or being overwhelmed by the amount of change in the images. The timely detection of se...

We suggest a method of optimizing resource allocation for real time protocol traffic in general, and VoIP in particular, within an H.323 environment. There are two options in the packet network to allocate resources: aggregate peak demand and statistical multiplexing. Statistical multiplexing, our choice for this case, allows the efficient use of t...

A method for generating the Delaunay triangulation of a given set of points efficiently in parallel is explored. Although Delaunay triangulation is well-defined for sequential processing architectures, a parallel implementation could improve performance and allow for larger problems to be computed than a serial architecture would ordinarily handle....

This paper explores the problem of atmospheric turbulence in long range video surveillance. This turbulence causes a phenomenon called heat scintillation or heat shimmer which introduces distortions into the video being captured. The nature of these distortions is discussed and a number of possible solutions explored. Using these solutions, three a...

In this paper we present a method of electronic beam steering for circular switched parasitic array (SPA) antennas. In circular SPA antennas, one achieves azimuth beam steering by open-circuiting and short-circuiting different parasitic elements, usually with only one parasitic element open-circuited at a time. For the SPA antenna with few parasiti...

Phased array antenna’s radiation pattern can be electronically controlled, making them a relevant solution for multipath interference. Electronically Steerable Parasitic Array Radiator (ESPAR) antenna systems are part of the family of phased array antennas under the umbrella of aerial beam-forming antennas. Generally ESPAR antenna system design con...

Access to information through telecentres is essential for social and economical growth in rural areas of sub-Saharan Africa. While many governments have established telecentres as means of bridging the increasingly wide digital divide in rural or unserved areas, their corresponding sustainability or continual operation is in doubt due to various c...

A method to determine the stationery probability of regions or feature points in a video sequence is proposed in this paper. This is done by identifying feature points using the Harris corner detector, finding descriptors for the feature points and then tracking the feature points. The information gained from tracking the feature points is then use...

The enthusiasm for the benefits of telecommunica-tion growth is unlimited; it promises to provide technological expansion and social economic development. This growth however , cannot be attained without proper public policy and a supportive regulatory framework. We are of the opinion that, well implemented regulatory and policy reform in a develop...

In this paper, we study price competition among multiple wireless service providers (WSPs) and propose a pricing model for such wireless oligopolies. In such oligopolies, each WSP has to compete with other WSPs for users while maximizing its profit. On the other hand, price- and congestion-sensitive users aim to maximize their compensated utilities...

Moment balancing templates have been proposed for channels with a small probability of an insertion/deletion (several orders smaller than additive errors) that add a minimal amount of redundancy. These templates are essentially a systematic way of encoding number-theoretic codes (primarily Levenshtein's s = 1 insertion/deletion code). Moment balanc...

Southern Africa Telecommunication Networks and Applications Conference (SATNAC), Spier Estate, Stellenbosch, South Africa, 5-8 September 2010 This paper presents a method of electronic beam steering for a smart antenna system based on a switched parasitic array. The antenna system is made up of circular array of half wave dipoles, with four parasit...

There is a growing demand for high definition (HD) graphics with multimedia content. This demand requires significantly more computational power than before. The increased demand in video content will continue to grow, resulting in vast volumes of data continuously shifted across networks and the internet. The volume of video data must be decreased...

Long range imaging systems that capture video through the atmosphere face a major problem in the form of atmospheric turbulence. This turbulence causes a phenomenon called heat shimmer which appears as a blurring and a wavering geometric distortion of the target scene which limits the effective range of the imaging system. We explore an image proce...

Research has shown that applications ported to utilize Graphics card hardware typicially show at least an order of magnitude performance increase. This is typically achieved due to suitability and scale of the problems to these processors. String matching problems, prevalent in the bioinformatics field, have a low computation to data ratio and ofte...

The Varshamov-Tenengol'ts codes are binary number-theoretic codes that can correct a single asymmetric error. Levenshtein realised that this same construction can correct a single insertion/deletion error. And yet asymmetric and insertion/deletion errors appear to be fundamentally different. This paper explores this scenario. Constantin and Rao sho...

This article proposes the use of an extended weighted Levenshtein distance to model the time depth between parent and direct descendant languages and also the dialectal separation between sibling languages. The parent language is usually a proto-language, a hypothetical reconstructed language, whose precise date is usually conjectural. Phonology is...

In this paper we study a duopoly pricing model under congestion-sensitive end-users by investigating a two access point (AP) providers' price competition in a wireless mesh network (WMN). The two AP providers resale IP-based service for possibly different prices and quality-of-service (QoS) to the end-users. The interactions among the two AP provid...

Southern Africa Telecommunication Networks and Applications Conference (SATNAC 2009). Swaziland, 30 August-2 September 2009 The electronically steerable parasitic array radiator (ESPAR) antenna system is configured with one feed radiating element and N-parasitic radiating elements. The radiation pattern is electronically controlled by means of the...

The development of Wireless Local Area Network (WLAN) technologies offers a novel platform for IP-based service resale via Wireless Mesh Networks (WMNs) that provide high network coverage and lower infrastructure cost. In this IP-based service resale business, the Access Point (AP) providers set their pricing policies as IP-based service resellers...

Compression is the most common process that limits the robustness of watermarking. In this paper, we propose a watermarking method for JPEG compressed color images in the semi-decompression domain, using Reed-Solomon (RS) codes. The watermark embedding and recovery processes can be applied without decompressing the compressed file completely. There...

Traditionally the field of inertial navigation systems was limited to high cost applications. However, recent advances in low cost MEMS based inertial sensors have resulted in the development of inertial navigations systems for the commercial market. The availability of these low cost navigation systems enabled a number of applications ideally suit...

In practical image storage and distribution systems. JPEG is a common image format. In this paper, we propose a blind watermarking method for JPEG-compressed color images in the semi-decompression domain by integrating the JPEG coding process. The watermark is embedded by modifying the quantized DC coefficients based on the spread spectrum techniqu...

In this paper we study a two access point (AP) providers' price competition in a wireless mesh network (WMN). The two AP providers offer IP-based service for possibly different prices and quality-of-service (QoS) in terms of mean packet delay. The end-users' choice between the APs is based on their compensated utility. We consider a two stage game...

Moment balancing templates have been proposed for channels with a small probability of an insertion/deletion (several orders smaller than additive errors) that add a minimal amount of redundancy. These templates are essentially a systematic way of encoding number-theoretic codes (primarily Levenshteinpsilas s = 1 insertion/deletion code). Moment ba...

A partitioned moment balancing template (systematic encoding of some number theoretic codes) is presented that can correct a single insertion/deletion. Instead of dispersing the moment balancing bits across the template, they are grouped together. Moment balancing templates are used to add insertion/deletion correcting capability to an additive-err...

The need for integrating operational risk man- agement into service level management for telecommunication service providers is discussed, where business operations such as described by TeleManagement Forum's eTOM (1) are predomi- nantly governed by a service level agreement. Operational risks that could affect the organization and its ability to c...

In this paper we present a detailed Graphics Processing Unit (GPU)-based implementation of the well known Canny edge detection algorithm. The aim of the paper is to provide an overview on our approach to implement the Canny edge detection algorithm, as it encompasses a set of image processing techniques. The result is an algorithm that can be appli...

In this paper, the need for integrating operational risk management into service level management for telecommunication service providers is discussed, where business operations are predominantly governed by a service level agreement. Operational risks that do or could effect the organization and its ability to comply with service level agreement r...

In this paper two face recognition techniques, principal component analysis (PCA) and linear discriminant analysis (LDA), are considered and implemented using a nearest neighbor classifier. The performance of the two techniques is then compared in facial recognition and detection tasks. The comparisons are done using a facial recognition database c...

This paper describes the problem of capturing video through turbulent atmosphere (also referred to as heat shimmer or heat scintillation) and describes some of the existing methods used in an attempt to counteract the problem. Within this problem of imaging through turbulent atmosphere there is a distinct lack of comparisons between methods and a r...

In this paper, the authors discuss the need for enterprise risk management and operational risk management in organizations where substantial elements of the business processes are governed by a service level agreement (SLA). To ensure the operational risk management is properly integrated into the operational support systems, we recommend the use...

There is a need to develop a risk management model for generic Operational Support Systems (OSS), preferably implemented on top of the eTOM framework. On closer inspection of the the eTOM framework it was discovered that risk management was virtually non-existent. After considering existing risk management recommendations such as the COSO KM framew...

It is firstly shown that the use of a fixed length decoding window in a channel that introduces insertions/deletions can propagate the errors to such an extent that stronger insertion/deletion correcting codes must be used. It is further shown that random insertion/deletion correcting codes based on the Levenshtein Distance are not optimal for such...

We present different techniques for designing codes with higher order spectral nulls, based on the power spectral density function; the binary representation of permutation codes and the finite state machine representation. Distance increasing mappings (a technique for mapping convolutional code outputs onto constrained symbols) is applied to gener...

We present a new insertion/deletion detection and correcting decoding scheme for convolutional codes that is based on the Viterbi decoding algorithm. Firstly, we show that, when using a coding scheme that utilises a standard rate, R=k/n, convolutional code and n Viterbi decoders in parallel, it is possible to correct up to n-1 consecutive deletions...

Compression is the most common process that limits the robustness of watermarking. We propose a watermarking method for JPEG compressed color images in the semi-decompression domain, using Reed-Solomon (RS) codes. The watermark embedding and recovery processes can be applied without decompressing the compressed file completely. There is no percepti...

It is firstly shown that the use of a fixed length decoding window in a channel that introduces insertions/deletions can propagate the errors to such an extent that stronger insertion/deletion correcting codes must be used. It is further shown that random insertion/deletion correcting codes based on the Levenshtein distance are not optimal for such...

In this paper, we present new constant weight and run properties of codes based on the Levenshtein distance. In our treatment, we assume no coding algorithm or structure, only that codebooks adhere to a minimum Levenshtein distance. We further show that these weight and run properties are related to the insertion/deletion correcting ability of a co...

Student feedback in traditional virtual classrooms is usually limited to intentional feedback. Information pertaining to the actual mental state (bored, interested, content, confused), gathered from facial expressions and gestures is lost. The paper focuses on methods to increase student feedback without placing unnecessary or excessive strain on a...

Multimedia services are exploited in a variety of different applications such as telemedicine, distance education, video conferencing, etc. In this study innovative ways of realizing multimedia distance education through satellite and cellular communications are investigated. Focus is on African scenarios that require affordable, available and low...

A new system for multimedia distance education through satellite and cellular communications for sub-Saharan Africa, is discussed. A satellite link from teacher to student is used which is completed by a global system for mobile communication and cellular return path which is from student back to the teacher. Custom-developed operating software at...

It is firstly shown that the use of a fixed length decoding window in a channel that introduces insertions/deletions can propagate the errors to such an extent that stronger insertion/deletion correcting codes must be used. It is further shown that random insertion/deletion correcting codes based on the Levenshtein distance are not optimal for such...

Constrained codes (alternatively called modulation codes, line codes or transmission codes) impose runlength or disparity constraints on the coded sequences, in order to either comply with the input restrictions of some communications channels, as determined by inter symbol interference or bandwidth limitations, or to aid in receiver synchronizatio...

A new binary, block-coding scheme for the correction of multiple insertion/deletion errors is presented. This coding scheme is based on similar theory to cyclic codes. A generator polynomial g(X) is used to generate a codebook Q. Constraints on valid generator polynomials are identified and an example of a generator polynomial is given.

We present a new insertion/deletion detection and correcting decoding scheme for convolutional codes that is based on the Viterbi decoding algorithm. Firstly, we show that, when using a coding scheme that utilises a standard rate, R=k/n, convolutional code and n Viterbi decoders in parallel, it is possible to correct up to n-1 consecutive deletions...

A relationship between cyclic shifts and the codebook Levenshtein distance is presented. This relationship is explored to show that Levenshtein distance-based codebooks have limited comma-freedom. This result is further used to devise a neural net-based decoder for insertion/deletion correction code books.

The class of punctured convolutional codes were first constructed by starting with low rate convolutional codes, and by periodically puncturing single bits out of some code symbols in a time varying trellis diagram. Thus, simplified Viterbi decoders could decode the resulting codes, with only two branches entering each state in the trellis diagram....

In this paper, new results on multiple symbol insertion and/or deletion correcting codes are presented. Firstly, new relationships between codebook properties and the symbol insertion and/or deletion correcting ability of a codebook are established. Secondly, new results on the upper bound of symbol insertion and/or deletion correcting codebook car...

Levenshtein proposed a class of single insertion/deletion correcting codes, based on the number-theoretic construction due to Varshamov and Tenengolt’s. We present several interesting results on the binary structure of these codes, and their relation to constrained codes with nulls in the power spectral density function. One surprising result is th...

Two new methods for the detection of multiple insertion/deletions are presented. The first method recognises insertions/deletions in the previous symbol stream by extracting additional information from commonly used markers. A new coding method is also presented that relies on the number of transitions in a codeword to detect insertions/deletions i...

We investigate the use of higher order code word moments to shape the power spectral density of codes. Several codes are presented that combine different spectral shaping techniques. The insertion/deletion and additive error correcting capabilities of these codes are investigated and simple decoding procedures are presented. Finally, we give an exa...

The authors present a class of binary codes that combine spectral shaping properties with additive error and synchronization error correcting capabilities, provided that only one of the above classes of errors occurs in a word. These codes are constructed by finding certain balanced subcodes of the single synchronization error correcting Levenshtei...

Spectral shaping techniques are applied to the insertion/deletion error correcting codes. Spectral shaping techniques are introduced and applied to insertion/deletion correcting codes. The attainable rates for subsides with spectral properties are computed and presented.

A coding method is presented that enables a receiver to detect and correct synchronization errors and additive errors, provided that only a single error occurs per code word. A code work consists of two segments, i.e. an information segment and a marker segment. The marker detects the occurrence of a synchronization error as well as the type of syn...

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