Publications


2013

2009

KALECHA, DRODUOLVITALIS.  2009.  System Overflow/Blocking Transients For Queues with Batch Arrivals Using a Family of Polynomials Resembling Chebyshev Polynomials, Vitalice K. Oduol, Cemal Ardil, International Journal of Applied Science, Engineering and Technology, Vol.5, No. 2, pp.102-1. International Journal of Applied Science, Engineering and Technology. : World Academy of Science, Engineering and Technology Abstract
The paper shows that in the analysis of a queuing system with fixed-size batch arrivals, there emerges a set of polynomials which are a generalization of Chebyshev polynomialsof the second kind. The paper uses these polynomials in assessing the transient behaviour of the overflow (equivalently call blocking) probability in the system. A key figure to noteis the proportion of the overflow (or blocking) probability resident in the transient component,which is shown in the results to be more significant at the beginning of the transient and naturally decays to zero in the limit of large t. The results also show that the significanceof transients is more pronounced in cases of lighter loads, but lasts longer for heavier loads.
KALECHA, DRODUOLVITALIS.  2009.  Frame and Burst Acquisition in TDMA Satellite Communication Networks with Transponder Hopping, Vitalice K. Oduol, Cemal Ardil, International Journal of Electronics, Communications and Computer Engineering, Vol.1, No.2, pp.100-105, July 2009. International Journal of Electronics, Communications and Computer Engineering. : World Academy of Science, Engineering and Technolgy Abstract
The paper presents frame and burst acquisition in a satellite communication network based on time division multiple access (TDMA) in which the transmissions may be carried on different transponders. A unique word pattern is used for the acquisition process. The search for the frame is aided by soft-decision of QPSK modulated signals in an additive white Gaussian channel. Results show that when the false alarm rate is low the probability of detection is also low, and the acquisition time is long. Conversely when the false alarm rate is high, the probability of detection is also high and the acquisition time is short. Thus the system operators can trade high false alarm rates for high detection probabilities and shorter acquisition times.
KALECHA, DRODUOLVITALIS.  2009.  Transient Analysis of a Single-Server Queue with Fixed-Size Batch Arrivals, Vitalice K. Oduol, Cemal Ardil, International Journal of Electronics, Communications and Computer Engineering Vol.1, No.1, pp.55-60, June 2009. International Journal of Electronics, Communications and Computer Engineering. : World Academy of Science, Engineering and Technolgy Abstract
The transient analysis of a queuing system with fixed-size batch Poisson arrivals and a single server with exponential service times is presented. The focus of the paper is on the use of the functions that arise in the analysis of the transient behaviour of the queuing system. These functions are shown to be a generalization of the modified Bessel functions of the first kind, with the batch size B as the generalizing parameter. Results for the case of single-packet arrivals are obtained first. The similarities between the two families of functions are then used to obtain results for the general case of batch arrival queue with a batch size larger than one.
KALECHA, DRODUOLVITALIS.  2009.  Performance of Block Codes Using the Eigenstructure of the Code Correlation Matrix and Soft-Decision Decoding of BPSK, Vitalice K. Oduol, Cemal Ardil, International Journal of Applied Science, Engineering and Technology Vol.5, No.1, pp.48-53, 2009. International Journal of Applied Science, Engineering and Technology Vol.5, No.1, pp.48-53, 2009. : World Academy of Science, Engineering and Technology Abstract
A method is presented for obtaining the error probability for block codes. The method is based on the eigenvalue-eigenvector properties of the code correlation matrix. It is found that under a unary transformation and for an additive white Gaussian noise environment, the performance evaluation of a block code becomes a one-dimensional problem in which only one eigenvalue and its corresponding eigenvector are needed in the computation. The obtained error rate results show remarkable agreement between simulations and analysis.
KALECHA, DRODUOLVITALIS.  2009.  BIP-Based Alarm Declaration and Clearing in SONET Networks Employing Automatic Protection Switching, Vitalice K. Oduol, Cemal Ardil, International Journal of Computer, Information, and Systems Science, and Engineering, Vol.3, No.1, pp.30-35, 2009. International Journal of Computer, Information, and Systems Science, and Engineering, Vol.3, No.1, pp.30-35, 2009. : World Academy of Science, Engineering and Technology Abstract
The paper examines the performance of bit-interleaved parity (BIP) methods in error rate monitoring, and in declaration and clearing of alarms in those transport networks that employ automatic protection switching (APS). The BIP-based error rate monitoring is attractive for its simplicity and ease of implementation. The BIP-based results are compared with exact results and are found to declare the alarms too late, and to clear the alarms too early. It is concluded that the standards development and systems implementation should take into account the fact of early clearing and late declaration of alarms. The window parameters defining the detection and clearing thresholds should be set so as to build sufficient hysteresis into the system to ensure that BIP-based implementations yield acceptable performance results.
KALECHA, DRODUOLVITALIS.  2009.  Transient Analysis of a Single-Server Queue with Batch Arrivals Using Modeling and Functions Akin to the Modified Bessel Functions, Vitalice K. Oduol, International Journal of Applied Science, Engineering and Technology, Vol.5, No.1, pp.34-39, 2009. International Journal of Applied Science, Engineering and Technology, Vol.5, No.1, pp.34-39, May 2009. : Kireti VM, Atinga JEO Abstract
The paper considers a single-server queue with fixed-size batch Poisson arrivals and exponential service times, a model that is useful for a buffer that accepts messages arriving as fixed size batches of packets and releases them one packet at time. Transient performance measures for queues have long been recognized as being complementary to the steady-state analysis. The focus of the paper is on the use of the functions that arise in the analysis of the transient behaviour of the queuing system. The paper exploits practical modelling to obtain a solution to the integral equation encountered in the analysis. Results obtained indicate that under heavy load conditions, there is significant disparity in the statistics between the transient and steady state values.

1999

KALECHA, DRODUOLVITALIS.  1999.  Data Flow and Buffer Management in a Multi-Channel Data Link Controller, S. Varada, V. Oduol, A. Shelat, Conference on Local Computer Networks, 1999. LCN '99,. International Journal of Applied Science, Engineering and Technology. : World Academy of Science, Engineering and Technology Abstract
The paper shows that in the analysis of a queuing system with fixed-size batch arrivals, there emerges a set of polynomials which are a generalization of Chebyshev polynomialsof the second kind. The paper uses these polynomials in assessing the transient behaviour of the overflow (equivalently call blocking) probability in the system. A key figure to noteis the proportion of the overflow (or blocking) probability resident in the transient component,which is shown in the results to be more significant at the beginning of the transient and naturally decays to zero in the limit of large t. The results also show that the significanceof transients is more pronounced in cases of lighter loads, but lasts longer for heavier loads.

1996

KALECHA, DRODUOLVITALIS.  1996.  "Integration of Wireless Local Loop (WLL) and VSATs For Rural Communications", V. K. Oduol,Presentation at INTELSAT, Washington, DC, May 1996. International Journal of Applied Science, Engineering and Technology. : World Academy of Science, Engineering and Technology Abstract
The paper shows that in the analysis of a queuing system with fixed-size batch arrivals, there emerges a set of polynomials which are a generalization of Chebyshev polynomialsof the second kind. The paper uses these polynomials in assessing the transient behaviour of the overflow (equivalently call blocking) probability in the system. A key figure to noteis the proportion of the overflow (or blocking) probability resident in the transient component,which is shown in the results to be more significant at the beginning of the transient and naturally decays to zero in the limit of large t. The results also show that the significanceof transients is more pronounced in cases of lighter loads, but lasts longer for heavier loads.

1995

KALECHA, DRODUOLVITALIS.  1995.  Rain Fade Mitigation, A. Dissanayake, V. Oduol, NASA ACTS Results Conference, Sept. 11-13,1995. International Journal of Applied Science, Engineering and Technology. : World Academy of Science, Engineering and Technology Abstract
The paper shows that in the analysis of a queuing system with fixed-size batch arrivals, there emerges a set of polynomials which are a generalization of Chebyshev polynomialsof the second kind. The paper uses these polynomials in assessing the transient behaviour of the overflow (equivalently call blocking) probability in the system. A key figure to noteis the proportion of the overflow (or blocking) probability resident in the transient component,which is shown in the results to be more significant at the beginning of the transient and naturally decays to zero in the limit of large t. The results also show that the significanceof transients is more pronounced in cases of lighter loads, but lasts longer for heavier loads.

1993

KALECHA, DRODUOLVITALIS.  1993.  Performance Evaluation of the Generalized Type-11 Hybrid ARQ Scheme with Noisy Feedback on Markov Channels, V.K. Oduol, S. D. Morgera, IEEE Transactions on Communications,. International Journal of Applied Science, Engineering and Technology. : World Academy of Science, Engineering and Technology Abstract
The paper shows that in the analysis of a queuing system with fixed-size batch arrivals, there emerges a set of polynomials which are a generalization of Chebyshev polynomialsof the second kind. The paper uses these polynomials in assessing the transient behaviour of the overflow (equivalently call blocking) probability in the system. A key figure to noteis the proportion of the overflow (or blocking) probability resident in the transient component,which is shown in the results to be more significant at the beginning of the transient and naturally decays to zero in the limit of large t. The results also show that the significanceof transients is more pronounced in cases of lighter loads, but lasts longer for heavier loads.

1991

KALECHA, DRODUOLVITALIS.  1991.  Satellite on-Board Processing", V. K. Oduol, Seminar Presentation at MPB Technologies, Montreal, Canada, October 1991.. International Journal of Applied Science, Engineering and Technology. : World Academy of Science, Engineering and Technology Abstract
The paper shows that in the analysis of a queuing system with fixed-size batch arrivals, there emerges a set of polynomials which are a generalization of Chebyshev polynomialsof the second kind. The paper uses these polynomials in assessing the transient behaviour of the overflow (equivalently call blocking) probability in the system. A key figure to noteis the proportion of the overflow (or blocking) probability resident in the transient component,which is shown in the results to be more significant at the beginning of the transient and naturally decays to zero in the limit of large t. The results also show that the significanceof transients is more pronounced in cases of lighter loads, but lasts longer for heavier loads.

1990

KALECHA, DRODUOLVITALIS.  1990.  Meteor Burst Communications in the Post 2000 Era, C. Marriott, V. Oduol, A. Ghosh, B.Tailor, IEEE Military Communications Conference, 1990. MILCOM '90, Conference Record, A New Era. 1990 IEEE, 1990. International Journal of Applied Science, Engineering and Technology. : World Academy of Science, Engineering and Technology Abstract
The paper shows that in the analysis of a queuing system with fixed-size batch arrivals, there emerges a set of polynomials which are a generalization of Chebyshev polynomialsof the second kind. The paper uses these polynomials in assessing the transient behaviour of the overflow (equivalently call blocking) probability in the system. A key figure to noteis the proportion of the overflow (or blocking) probability resident in the transient component,which is shown in the results to be more significant at the beginning of the transient and naturally decays to zero in the limit of large t. The results also show that the significanceof transients is more pronounced in cases of lighter loads, but lasts longer for heavier loads.

1989

KALECHA, DRODUOLVITALIS.  1989.  Soft-Decision Decoding Applied to the Generalized Type-11 Hybrid ARQ Scheme, S. D. Morgera, V.K Oduol,. IEEE Transactions on Communications, Volume: 37 Issue: 4, April 1989. International Journal of Applied Science, Engineering and Technology. : World Academy of Science, Engineering and Technology Abstract
The paper shows that in the analysis of a queuing system with fixed-size batch arrivals, there emerges a set of polynomials which are a generalization of Chebyshev polynomialsof the second kind. The paper uses these polynomials in assessing the transient behaviour of the overflow (equivalently call blocking) probability in the system. A key figure to noteis the proportion of the overflow (or blocking) probability resident in the transient component,which is shown in the results to be more significant at the beginning of the transient and naturally decays to zero in the limit of large t. The results also show that the significanceof transients is more pronounced in cases of lighter loads, but lasts longer for heavier loads.

1988

KALECHA, DRODUOLVITALIS.  1988.  Soft-Decision Decoding Applied to the Generalized Type-11 Hybrid ARQ Scheme, S. D. Morgera, V. Oduol, IEEE International Conference on Communications, vol.2, 1988,. International Journal of Applied Science, Engineering and Technology. : World Academy of Science, Engineering and Technology Abstract
The paper shows that in the analysis of a queuing system with fixed-size batch arrivals, there emerges a set of polynomials which are a generalization of Chebyshev polynomialsof the second kind. The paper uses these polynomials in assessing the transient behaviour of the overflow (equivalently call blocking) probability in the system. A key figure to noteis the proportion of the overflow (or blocking) probability resident in the transient component,which is shown in the results to be more significant at the beginning of the transient and naturally decays to zero in the limit of large t. The results also show that the significanceof transients is more pronounced in cases of lighter loads, but lasts longer for heavier loads.

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