Bio

PROF. ABSALOMS, HEYWOOD OUMA

Personal Information

Research Interest

Academic: Heuristic Optimization in Telecommunication Systems, Signal and Image Processing, SDR . General: Christian Living, IT, Sports

Responsibilities

Lecturer, IEEE SB Counsellor, PhD and MSc Supervisor

Specialization Areas

Telecommunication Signal and Image Processing

PROF. ABSALOMS HEYWOOD OUMA CV

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(Last updated: November 17, 2021)

Publications

2021

Rop, KV, Langat PK, Ouma HA.  2021.  Spectrum Sensing on High Density Cognitive Radio Vehicular Ad Hoc Network. ,” Journal of Communications (JCM). 16(7):259-266.

2020

Kerosi, J, Ouma H, Langat K.  2020.  Sum Rate and Fairness Maximization in Device-to-Device Communication Underlaying Cellular Networks. International Journal of Scientific and Technology Research (IJSTR). 9(2):6438-6443.
Ombongi, FO, Absaloms HO, Kibet PL.  2020.  Energy Efficient Resource Allocation in Millimeter-Wave D2D Enabled 5G Cellular Networks. Engineering, Technology and Applied Science Research (ETASR). 10(4):6152-6160.
Ombongi, FO, Absaloms HO, Kibet PL.  2020.  Channel and Power Allocation for mm-wave Device-to-Device Enabled Vehicular Network. International Journal of Scientific and Technology Research (IJSTR). 9(9):294-300.

2019

Ombongi, FO, Absaloms HO, Kibet PL.  2019.  Resource Allocation in Millimeter-wave Device-to-Device Networks. Mobile Information Systems. 2019

2013

Rop, KV, Ouma DHA, O. PKDB.  2013.  APPLICATION OF ADAPTIVE NEURO-FUZZY INFERENCE SYSTEM TECHNIQUE IN DESIGN OF RECTANGULAR MICROSTRIP PATCH ANTENNAS. JAGST. 15(1):147.dr._ouma_et_al.pdf

2012

Nyaory, GM, K’Onditi DBO, Ouma HA, Musyoki S.  2012.  Analysis of Electromagnetic Field Radiation from a Rectangular Cavity-Backed Slot Antenna Using ADI-FDTD Method. Journal Of Information Engineering and Applications . 2(No. 8):1-8. Abstract

In this paper, a rectangular Cavity Backed Slot Antenna (CBSA) Model excited by a probe is investigated.
The analysis is carried out using the Alternating Direction Implicit - Finite Difference Time Domain (ADIFDTD)
Method which is applied to investigate its characteristics in terms of radiation patterns and power.
This is because the method is capable of providing a more accurate definition of the electromagnetic fields
within the rectangular apertures, while eliminating the Courant-Friedrich-Levy (CFL) stability condition
which is present in the regular Finite Difference Time Domain (FDTD) method. A cavity-backed slot
antenna structure with dimensions of 14cm×22cm×30cm is analyzed with the slot and aperture
measurements done at 3GHz. Results showing current distribution on the material surrounding the
apertures are presented and a discussion on the physical aspects of the aperture radiation phenomenon is
also presented.

**This research was sponsored by The German Academic Exchange Service (DAAD)**
Rop, KV, KONDITI DBO, H.A. O, Musyoki S.  2012.  Parameter Optimization in Design of a Rectangular Microstrip Patch Antenna Using Adaptive Neuro-Fuzzy Inference System Technique. International Journal of Technical and Physical Problems of Engineering (IJTPE). 4(12):16-23. Abstract

Modern wireless systems are placing greater
emphasis on antenna designs for future development in
communication technology because the antenna is a key
element in the overall communication system. A
Microstrip Antenna is well suited for wireless
communication due to its light weight, low volume and
low profile planar configuration which can be easily
conformed to the host surface. In this paper, an
optimization method based on adaptive neuro-fuzzy
inference system (ANFIS) for determining the parameters
used in the design of a rectangular microstrip patch
antenna is presented. The ANFIS has the advantages of
expert knowledge of fuzzy inference system (FIS) and the
learning capability of artificial neural network (ANN). By
calculating and optimizing the patch dimensions and the
feed point of a rectangular microstrip antenna, this paper
shows that ANFIS produces good results that are in
agreement with Ansoft HFSS 13.0 simulation results.
Nyaory, GM, K’Onditi DBO, Ouma HA, Musyoki S.  2012.  Distribution of Electromagnetic Field Radiation from a Rectangular Cavity-Backed Slot Antenna, ADI-FDTD Perspective, August. KSEEE-JSAEM 2012 International Engineering Conference.

2011

Nyaory, GM, Konditi DBO, Ouma HA, Musyoki S.  2011.  Designing Cavity–Backed Slot Antenna Array: A Numerical Implementation Using ADI-FDTD Method, Nov. 6th JKUAT Scientific and Technological Conference. , AICAD, Juja, Nairobi Abstract

ABSTRACT Slotted antenna arrays used with waveguides also known as Cavity-backed slot antenna arrays (CBSAA) are a popular set of antenna in navigation, radar and other microwave-frequency systems. For such antenna analysis and design in the sub-wavelength domain, there are currently three well established methods: The method of moments (MoM), the finite-element method (FEM) and the finite difference time-domain method (FDTD).
In this paper, a new finite-difference time-domain (FDTD) algorithm is proposed in order to eliminate the Courant–Friedrich–Levy (CFL) condition restraint. We therefore present the conventional alternating direction implicit - finite difference time-domain method (ADI-FDTD) method.
The proposed ADI-FDTD method is applied by solving Maxwell’s equations in time domain. We model and simulate waveguide structures with a case study of T10 mode on rectangular CBSAA consisting of 8 slot elements backed by a single cavity and simple feed network. The characteristics covering the microwave frequencies are analyzed, for instance; input impedance, return loss, bandwidth, VSWR, and far field radiation patterns. Moreover, several numerical results are presented, along with measured data, which demonstrate the validity, efficiency, and capability of the technique. Index Terms - Cavity-Backed Slot Antenna Arrays (CBSAA), Finite Difference Time-Domain (FDTD), Courant–Friedrich–Levy (CFL), and Alternating Direction Implicit (ADI)

2010

KONDITI, DBO, MAKICHE JK, ABSALOMS HO, ADIKA CO, KOECH EK, Dharmathikary VM.  2010.  Practical and Theoretical Evaluation of EMC/EMI: Problems of Metallic Enclosures with Apertures. International Journal of Technical and Physical Problems of Engineering (IJTPE). 1(4):1-8. Abstract

PRACTICAL AND THEORETICAL EVALUATION OF EMC/EMI
Problems of Metallic Enclosures with Apertures

D.B.O. Konditi1 J.K. Makiche2 H.O. Absaloms3 C.O. Adika2 E.K. Koech2
V. M. Dharmadhikary3

1 Faculty of Engineering, Multimedia University College of Kenya, Nairobi, Kenya, onyango_d@yahoo.co.uk, dkonditi@mmu.ac.ke
2 Department of Telecommunication and Information Engineering, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya, jkmakiche@yahoo.co.uk, otychriss@yahoo.com, ekipyegon@yahoo.com
3 Department of Electrical and Information Engineering, University of Nairobi, Nairobi, Kenya, houma@ieee.org, dharmavasudha@gmail.com

Abstract- In this paper, experimental and theoretical evaluation of coupling of electromagnetic radiation is reported. Validation of the results is obtained by comparing the experimental data with theoretical data both generated using CONCEPT Simulator and data from our hybrid MoM/FDTD formulation for the analysis of metallic enclosure with apertures. Both the CONCEPT Simulator and the hybrid MoM/FDTD formulation utilize the method of moments, however, the hybridization of the latter makes it more adaptive to the solutions of apertures of arbitrary shape within enclosures with inhomogeneous dielectrics. The problems analyzed are rectangular slot, cross-shaped aperture and diamond-shaped aperture. The experimental results and MoM/FDTD results also agree fairly well with those available in the literature.

Keywords: Shielding effectiveness, metallic enclosures, method of moments, finite difference time domain, EMI/EMC.

K., MJ, O. KDB, A. OH.  2010.  A Hybrid MOM/FDTD Formulation for EMC/EMI Problems Of Metallic Enclosures with Apertures, 4 Aug. KSEEE-JSAEM 2010 International Conference. , MMUCK, Nairobi: International Journal of Technical and Physical Problems of Engineering (IJTPE) Abstract

A HYBRID MOM/FDTD FORMULATION FOR EMC/EMI PROBLEMS OF METALLIC ENCLOSURES WITH APERTURES

Josiah K. Makiche1 Dominic B. O. Konditi2, Heywood A. Ouma3
jkmakiche@yahoo.co.uk konditi_dom@yahoo.co.uk houma@ieee.org

1Department of Telecommunication and Information Engineering, Jomo Kenyatta University of Agriculture and Technology. 2Faculty of Engineering, Multimedia University College of Kenya. 3Department of Electrical and Information Engineering, University of Nairobi

Abstract—In this work a hybrid Method-of-Moments/Finite-Difference-Time-Domain (MoM/FDTD) formulation for the analysis of a metallic enclosure with an aperture is developed. The equivalence principle is used to divide the problem into two regions, region 1 and region 2, each of which is treated separately. The induced aperture magnetic currents are obtained via a moments method solution of the mixed potential integral equation using the generalized network formulation and triangular patch modeling. The computed magnetic current is directly incorporated into FDTD formulations as a source to determine the fields in the interior of the enclosure (region 2). The formulations are implemented in a computer code and used to analyze a typical problem of a rectangular enclosure with an aperture. The results are validated using data available in literature.
Keywords: Shielding effectiveness, metallic enclosures, method of moments, finite difference time domain, EMI/EMC.

2009

ABSALOMS, HO.  2009.  Status of iLabs in sub-Sahara Africa (iLabs-Africa), 07. , New York: Carnegie Corporation of New York

2008

K., MJ, O. KDB, A. OH.  2008.  A Hybrid MoM/FDTD Formulation for EMC/EMI Problems of Metallic Enclosures with Apertures. 4th JKUAT Scientific and Technological Conference. , JKUAT, Nairobi

2006

O., OM, O KDB, A. OH.  2006.  Microwave Response to Moisture Content. 2nd JKUAT Scientific and Technological Conference. , JKUAT, Nairobi

2004

H., A, T. T.  2004.  Meta-GA Multi-Window Human Eye Detection. 8th World Multi-Conference on Systems, Cybernetics and Informatics, SCI 2004. :165-170., Orlando, Florida, USA

2002

ABSALOMS, HO.  2002.  A Study Of Internet Use In Kenyan Universities : A component of the project ‘An Exploratory Study Of Internet Use At Institutions of Higher Education: Africa, Asia and Latin-America’ , 09. , Amsterdam: UNU/INTECH and The International Institute of Infonomics, The Netherlands

1999

H., A, Y. I, T. T.  1999.  A Heuristic Approach to Solution of Industrial Optimisation Problems. 5th Africon Conference in Africa, IEEE AFRICON ‘99. :127-130., Cape Technikon, Cape Town, South Africa
H., A, T. T.  1999.  GA Relaxation Labeling. Trans. IEEJ. 119-C(12):1489-1499.

1998

H., A, T. T.  1998.  Optimization by Genetic Algorithm. 4th KSEEE International Conference. , Nairobi, Kenya
H, A, T. T.  1998.  A Genetic Algorithm Solution to Relaxation Labeling of Line Images. Trans. IEEJ. 118-C(11):1670-1671.
Absaloms, HO.  1998.  Genetic Algorithm Application to Image Processing Optimization Problems. , Atsugi, Japan: Kanagawa Institute of Technology

1997

H., A, T. T.  1997.  Applying Genetic Algorithm to Labeling. 3rd KSEEE International Conference. :62-68., Nairobi, Kenya
H, A, T. T.  1997.  Wire-Frame Approximation of Surface from Contour Data by GA. Trans. IEEJ. 117-C(2):207-208.
H., A, T. T.  1997.  A Novel Approach to Triangulating Contours for Surface Approximation. Trans. IEEJ. 117-C(6):667-675.

1996

H., A, T. T.  1996.  Surface Reconstruction by Triangulation Using GA. 20th International Conference on Computers and Industrial Engineering (ICC&IE`96). :441-444., Kyongju, Korea
H., A, T. T.  1996.  A Study of Human Eyes’ Detection by Window-Pair Chasing. Trans. IEEJ. 116-C(9):1015-1028.

1995

H., A, T. T.  1995.  A Detection Of Human Eyes by Window-Pair Chasing. 1st KSEEE International Conference. :205-214., Nairobi, Kenya

1994

Absaloms, HO, others.  1994.  PCB CAD Training Manual.

1993

Seneveratne, A, Absaloms H, Ginige T, Fry M.  1993.  Effect of Timer Management on Protocol Execution Performance. 2nd Australian Conference on Telecommunications Software (ACTS’93,) . :149-156., Wollongong, Australia

1992

O., AH.  1992.  Timer Server Implementation in Computer Communication Protocols. , Sydney, Australia: University of Technology, Sydney (UTS)
H., A.  1992.  Timer Server Implementation in Computer Communication Protocols. Third Annual JKUAT Electrical Engineering Seminar . , Nairobi, Kenya

1988

Absaloms, HO.  1988.  The Yagi-Uda Array, 07. , Nairobi, Kenya: University of Nairobi

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