A note on non-binary multiple insertion/deletion correcting codes
- Paluncic, Filip, Swart, Theo G., Weber, Jos H., Ferreira, Hendrik C., Clarke, Willem A.
- Authors: Paluncic, Filip , Swart, Theo G. , Weber, Jos H. , Ferreira, Hendrik C. , Clarke, Willem A.
- Date: 2011
- Subjects: Insertion/deletion , Correcting codes
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/20202 , uj:16077 , ISBN: 978-1-4577-0437-6 , Citation: Paluncic, F. et al. 2011. A note on non-binary multiple insertion/deletion correcting codes. Proceedings of the IEEE Information Theory Workshop, 16-20 October, 2011, Paraty, Brazil.
- Description: Abstract: 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 on the cardinality of a maximal binary multiple insertion/deletion correcting code derived by Levenshtein.
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- Authors: Paluncic, Filip , Swart, Theo G. , Weber, Jos H. , Ferreira, Hendrik C. , Clarke, Willem A.
- Date: 2011
- Subjects: Insertion/deletion , Correcting codes
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/20202 , uj:16077 , ISBN: 978-1-4577-0437-6 , Citation: Paluncic, F. et al. 2011. A note on non-binary multiple insertion/deletion correcting codes. Proceedings of the IEEE Information Theory Workshop, 16-20 October, 2011, Paraty, Brazil.
- Description: Abstract: 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 on the cardinality of a maximal binary multiple insertion/deletion correcting code derived by Levenshtein.
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Alignment invariant image comparison implemented on the GPU
- Roos, Hans, Roodt, Yuko, Clarke, Willem A.
- Authors: Roos, Hans , Roodt, Yuko , Clarke, Willem A.
- Date: 2008
- Subjects: Distance transform , Binary image , Graphics processing units , Parallel processing
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/15593 , uj:15681 , Roos, H., Roodt, Y. & Clarke, W.A. 2008. Alignment invariant image comparison implemented on the GPU. Pattern Recognition Association of South Africa (PRASA), 27-28 Nov. 2008.
- Description: Abstract: This paper proposes a GPU implemented algorithm to determine the differences between two binary images using Distance Transformations. These differences are invariant to slight rotation and offsets, making the technique ideal for comparisons between images that are not perfectly aligned...
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- Authors: Roos, Hans , Roodt, Yuko , Clarke, Willem A.
- Date: 2008
- Subjects: Distance transform , Binary image , Graphics processing units , Parallel processing
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/15593 , uj:15681 , Roos, H., Roodt, Y. & Clarke, W.A. 2008. Alignment invariant image comparison implemented on the GPU. Pattern Recognition Association of South Africa (PRASA), 27-28 Nov. 2008.
- Description: Abstract: This paper proposes a GPU implemented algorithm to determine the differences between two binary images using Distance Transformations. These differences are invariant to slight rotation and offsets, making the technique ideal for comparisons between images that are not perfectly aligned...
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An analogue to SNR for timing synchronisation motivated by jitter and insertion/deletion errors
- Paluncic, Filip., Clarke, Willem A., Swart, Theo G., Ferreira, Hendrik C.
- Authors: Paluncic, Filip. , Clarke, Willem A. , Swart, Theo G. , Ferreira, Hendrik C.
- Date: 2007
- Subjects: Signal-to-noise ratio , Timing jitter , Insertion/deletion errors
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/15424 , uj:15659 , Citation: Paluncic, F. et al. 2007. An analogue to SNR for timing synchronisation motivated by jitter and insertion/deletion errors. In: Proceedings of the International Symposium on Communication Theory and its Applications, Ambleside, England, July 16-20, 2007.
- Description: Abstract: This paper takes a closer look at the relationship between insertion/deletion errors and one of its most common causes, timing jitter. We consider two insertion/deletion channel models based on different assumptions about the timing jitter. In the literature, only channels with equal insertion/deletion probabilities for each bit have been considered. However, this assumption is only true under certain conditions. A channel, where the probability of insertion/deletion errors increases with time, is another feasible scenario. We derive an approximation for the probability of insertion/deletion errors for both models. With these ideas, we also define a possible counterpart in the time domain to the signal-to-noise ratio (defined in the amplitude domain). As an analogue to Gaussian noise in the amplitude domain, we only consider random Gaussian distributed jitter.
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- Authors: Paluncic, Filip. , Clarke, Willem A. , Swart, Theo G. , Ferreira, Hendrik C.
- Date: 2007
- Subjects: Signal-to-noise ratio , Timing jitter , Insertion/deletion errors
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/15424 , uj:15659 , Citation: Paluncic, F. et al. 2007. An analogue to SNR for timing synchronisation motivated by jitter and insertion/deletion errors. In: Proceedings of the International Symposium on Communication Theory and its Applications, Ambleside, England, July 16-20, 2007.
- Description: Abstract: This paper takes a closer look at the relationship between insertion/deletion errors and one of its most common causes, timing jitter. We consider two insertion/deletion channel models based on different assumptions about the timing jitter. In the literature, only channels with equal insertion/deletion probabilities for each bit have been considered. However, this assumption is only true under certain conditions. A channel, where the probability of insertion/deletion errors increases with time, is another feasible scenario. We derive an approximation for the probability of insertion/deletion errors for both models. With these ideas, we also define a possible counterpart in the time domain to the signal-to-noise ratio (defined in the amplitude domain). As an analogue to Gaussian noise in the amplitude domain, we only consider random Gaussian distributed jitter.
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Beam steering for circular switched parasitic arrays using a combinational approach
- Mofolo, Mofolo R. O., Lysko, Albert A., Olwal, Thomas O., Clarke, Willem A.
- Authors: Mofolo, Mofolo R. O. , Lysko, Albert A. , Olwal, Thomas O. , Clarke, Willem A.
- Date: 2011
- Subjects: Antenna radiation patterns , Circular switched parasitic arrays , Electronic beam steering
- Type: Article
- Identifier: uj:6090 , ISSN 978-1-61284-992-8 , http://hdl.handle.net/10210/10949
- Description: 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 parasitic elements, this results in low azimuth beam steering resolution. In the proposed method, we iterate through different combinations of parasitic elements and the possible switch states of the lumped impedance loads connected to the parasitic elements. Our method aims to increase the azimuth beam steering resolution of the circular SPA antennas. The method is verified using a combination of simulation (using both MATLAB and WIPL-D) and a SPA antenna prototype implementation. The MATLAB code uses the induced EMF method, while the WIPL-D uses the Methods of Moment (MoM) for solving the antenna impedances. The three sets of results (simulations and measurement) match very well at 2.4 GHz. The results indicate the availability of more options (different loading configurations) for electronic beam switching that can be adopted to improve the beam steering resolution of circular SPA antennas.
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- Authors: Mofolo, Mofolo R. O. , Lysko, Albert A. , Olwal, Thomas O. , Clarke, Willem A.
- Date: 2011
- Subjects: Antenna radiation patterns , Circular switched parasitic arrays , Electronic beam steering
- Type: Article
- Identifier: uj:6090 , ISSN 978-1-61284-992-8 , http://hdl.handle.net/10210/10949
- Description: 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 parasitic elements, this results in low azimuth beam steering resolution. In the proposed method, we iterate through different combinations of parasitic elements and the possible switch states of the lumped impedance loads connected to the parasitic elements. Our method aims to increase the azimuth beam steering resolution of the circular SPA antennas. The method is verified using a combination of simulation (using both MATLAB and WIPL-D) and a SPA antenna prototype implementation. The MATLAB code uses the induced EMF method, while the WIPL-D uses the Methods of Moment (MoM) for solving the antenna impedances. The three sets of results (simulations and measurement) match very well at 2.4 GHz. The results indicate the availability of more options (different loading configurations) for electronic beam switching that can be adopted to improve the beam steering resolution of circular SPA antennas.
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Optimization of resources for H.323 endpoints and terminals over VoIP networks
- Nlend, Samuel, Swart, Theo G., Clarke, Willem A.
- Authors: Nlend, Samuel , Swart, Theo G. , Clarke, Willem A.
- Date: 2011
- Subjects: VoIP Networks , Statistical multiplexing , Telecommunications
- Language: English
- Type: Conference paper
- Identifier: http://hdl.handle.net/10210/139763 , uj:15455 , S. Nlend, T. G. Swart and W. A. Clarke, "Optimization of resources for H.323 endpoints and terminals over VoIP networks," in Proceedings IEEE Africon, Livingstone, Zambia, September 13-15, 2011, published on CD (5 pages)
- Description: 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 the network resources but however exhibits greater packet delay variation and packet transfer delay. These delays are often the result of correlations or time dependency experienced by the system’s queue due to the variations observed in different point processes that occur at a point of time. To address these issues, we suggest a queuing method based on the diffusion process approximated by Orstein-Ulenbeck and the non-validated results of Ren and Kobayashi.
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- Authors: Nlend, Samuel , Swart, Theo G. , Clarke, Willem A.
- Date: 2011
- Subjects: VoIP Networks , Statistical multiplexing , Telecommunications
- Language: English
- Type: Conference paper
- Identifier: http://hdl.handle.net/10210/139763 , uj:15455 , S. Nlend, T. G. Swart and W. A. Clarke, "Optimization of resources for H.323 endpoints and terminals over VoIP networks," in Proceedings IEEE Africon, Livingstone, Zambia, September 13-15, 2011, published on CD (5 pages)
- Description: 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 the network resources but however exhibits greater packet delay variation and packet transfer delay. These delays are often the result of correlations or time dependency experienced by the system’s queue due to the variations observed in different point processes that occur at a point of time. To address these issues, we suggest a queuing method based on the diffusion process approximated by Orstein-Ulenbeck and the non-validated results of Ren and Kobayashi.
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Optimization of resources for H.323 endpoints and terminals over VoIP networks
- Nlend, Samuel, Swart, Theo G., Clarke, Willem A.
- Authors: Nlend, Samuel , Swart, Theo G. , Clarke, Willem A.
- Date: 2011
- Subjects: H.323 endpoints , VoIP networks
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/18245 , uj:15976 , ISBN: 978-1-61284-993-5 , Citation: Nlend, S., Swart, T.G. & Clarke, W.A. 2011. Optimization of resources for H.323 endpoints and terminals over VoIP networks. Proceedings IEEE Africon, 13-15 September, Livingstone, Zambia.
- Description: Abstract: 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 the network resources but however exhibits greater packet delay variation and packet transfer delay. These delays are often the result of correlations or time dependency experienced by the system’s queue due to the variations observed in different point processes that occur at a point of time. To address these issues, we suggest a queuing method based on the diffusion process approximated by Orstein-Ulenbeck and the non-validated results of Ren and Kobayashi.
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- Authors: Nlend, Samuel , Swart, Theo G. , Clarke, Willem A.
- Date: 2011
- Subjects: H.323 endpoints , VoIP networks
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/18245 , uj:15976 , ISBN: 978-1-61284-993-5 , Citation: Nlend, S., Swart, T.G. & Clarke, W.A. 2011. Optimization of resources for H.323 endpoints and terminals over VoIP networks. Proceedings IEEE Africon, 13-15 September, Livingstone, Zambia.
- Description: Abstract: 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 the network resources but however exhibits greater packet delay variation and packet transfer delay. These delays are often the result of correlations or time dependency experienced by the system’s queue due to the variations observed in different point processes that occur at a point of time. To address these issues, we suggest a queuing method based on the diffusion process approximated by Orstein-Ulenbeck and the non-validated results of Ren and Kobayashi.
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