Volume 27, No. 2 (2021)
Articles
MODELING AND SIMULATION OF A DUAL CHANNEL ACTIVE NOISE CONTROL SYSTEM FOR POWER TRANSFORMER USING FXLMS ALGORITHM
SUNDAY ADETONA(*1), RAIFU SALAWU(2), MORUF ALABI(2)
Power transformers are known to generate noise, however, active noise emanating from power transformers many at time is unbearable and has been a subject of concern overtime in power engineering. Several studies on it have principally centered on single channel active noise controller (scANC) using fixed step size, which are characterized with the problems such as signal congestion and instability. This study, therefore, employed Filtered-X Least Mean Square (FXLMS) on a dual channel active noise controller (dcANC) using variable step-size. The noise emanating from a 100 MVA, 132/33 kV power transformer was captured with the help of a smart phone in flight mode in accordance with IEC 60076-10 standard of 2 m away from the transformer and 1 m apart between each measurement. The recorded noises were taken at one-third of the height of the transformer tank, while electromagnetic interference from the phone and others were assumed to be negligible. A dcANC with FXLMS was model mathematically and implemented in Simulink in the MATLAB environment. Noise reduction ratio, loudness unit full scale and mean square error were used as performance metrics. The simulation results obtained showed that the original noise emanating from the power transformer when ANC was not used was found to be 70 dB. When scANC with FXLMS was used, the noise was reduced to 30.55 dB whereas, when dcANC with the FXLMS was employed it was reduced to 0.19 dB. Also, the MSE value of -72 dB was obtained in the proposed dcANC with FXLMS, compared with -64 dB obtained from scANC with FXLMS algorithm. The results of the simulation using FXLMS on both scANC and dcANC showed that the performance of the dcANC is comparatively better in term of the stated performance metrics.
TUBING SYSTEM PERFORMANCE PROFILING OF DRY GAS WELLS USING NEWTON RAPHSON ITERATION METHOD
OKOLOGUME CHINEDU WILFRED(*1), OMONUSI ROTIMI(1)
This paper focusses on the use of Newton Raphson iteration in determining gas compressibility factor (z) while performing tubing system performance for dry gas wells through the development of a computer model (TBG_SPARK). However, tubing performance analysis performed on the case study (Well-A and Well-B) revealed that the production system of Well-B performed better – since its tubing size and wellhead pressure was lower than that of Well-A. Also, investigations made using modified data revealed that, lower tubing sizes and higher wellhead pressures yield higher gas rates. Conversely, reverse was the case when wellhead pressures were not varied.
ANALYTICAL STUDY OF THE STATIC THERMOMECHANICAL STRESSES OF THE ASSEMBLIES WITH OPTIONAL RING FLANGES. ROTATION OF THE FLANGE RING AROUND THE CIRCUMFERENCE OF CENTERS FOR BOLT HOLES
RADU I. IATAN(*1), GHEORGHITA TOMESCU(1), GEORGETA ROMAN [URSE](1), MELANIA CORLECIUC [MITUCA](1), IOLANDA CONSTANTA PANAIT(1)
This paper addresses the evaluation of thermal and mechanical stresses that occur in assemblies with flat ring flanges, of optional type. The flange rings are fixed by welding to the wall of the cylindrical body of the vessel, with a constant thickness along its length. Regarding of the above, the compatibility of the deformations of the component elements (radial displacements and rotations) is approached. A linear algebraic system is formed in which both external loads (pressure, temperature) and connecting loads (bending unit moments and unit forces) are present. The present analysis discusses the quantitative, cumulative effect of the deformed gasket and the stiffness of the curved/bent screws on the tightness of the system. The methodology is flexible by introducing selection factors so that the mentioned influences can be easily separated.
PRIVATE SECURITY SURVEILLANCE SYSTEM
BENJAMIN KOMMEY(*1), SETH KOTEY(1), ERIC TUTU(1), DANIEL OPOKU(1)
Security is an essential need for man. Without the sense of security, daily human activities will be greatly affected. Most people go to great lengths to ensure there is a presence of security in their environment, often employing dedicated personnel to keep watch over them and their property. This paper proposes a design of a microcontroller based electronic security system which helps to detect possible intruders to a home. This security system is designed to reduce the need of having personnel stationed as security guards over a home. It has the primary unit called the Area Watch Unit (AWU) consisting of a motion detection unit that effectively detects motion around specified perimeters which is then followed by a computer vision to identify and classify what caused the motion. A facial recognition algorithm is run on the face extracted from the image captured after the object that caused the motion is identified and classified as human. Access is then granted to the individual if the results from the facial recognition is positive otherwise a message is sent to the owner of the home indicating a possible intruder is present. There is also a Final Recovery Unit (FRU) which sends a message to the owner of the home and sounds an alarm whiles flashing lights in the event that the Area Watch Unit (AWU) is by-passed without authority.
EXPERIMENTAL ANALYSIS OF THE MECHANICAL BEHAVIOR OF CLAY-CEMENT BLOCKS REINFORCED WITH COCONUT FIBERS
CONAND HONORÉ KOUAKOU(*1), MORO OLIVIER BOFFOUE(1), ANGE CHRISTINE DJOHORE(1), KOFFI CLÉMENT KOUADIO(1), EDJIKÉMÉ EMERUWA(1)
This article aims for analyzing under an axial stress, the behavior of earth blocks reinforced by various proportions of coconut fibers. For this fact, compressive and flexural tests were carried out after 28 days of maturation, on dry blocks elaborate with clay stabilized at 8% of cement and containing 0 to 1% of fibers 30 mm length. The experimental results show that the incorporation of fibers in the blocks improves their mechanical characteristics, increases their ductile deformation and delays their cracking. The best mechanical resistances are obtained at 0.8% of fibers because at this content, the distance between fibers is optimal.
CHEMICAL ANALYSIS OF WATER SOURCED FROM ODO ONA RIVER, IBADAN, SOUTH-WESTERN NIGERIA
FIDELIS NKESHITA(*1), ADEBOLA ADEKUNLE(1), ADEBAYO ADEDEJI(1)
The water samples were collected at three different periods of the year from locations around the Oluyole Estate Industrial hub housing many industries and located in Ibadan, South-Western Nigeria. The observed values of the concentration of Aluminium, Chromium, Iron and Sodium show varied concentrations for Sodium (3.01 – 38.02) mg/L, Iron (0.8 – 28.68) mg/L, Chromium (0 – 0.38) mg/L, Arsenic (Not detected) and Aluminium (0 - 0.24) mg/L. The results were compared with standard values of the parameters under consideration as recommended by the World Health Organization (WHO).
OPTIMIZATION OF SINGLY REINFORCED BEAM DESIGN USING SIMULATED ANNEALING
SIMON OLAYIWOLA ADEREMI OLAWALE(1), OLUTOSIN PETER AKINTUNDE(*1), MOSES OLADIPUPO AFOLABI(1), OLUWOLE AKINYELE AGBEDE(1), OLUSOLA OLAYEMI FADIPE(2)
This paper investigated the optimization of a singly reinforced concrete beam using the simulated annealing. The enhancement of minimum cost of structures and the adoption of the algorithm method of simulated annealing were projected in resolving the complications of constraints associated with optimization problems. The variables are the width, depth, compression steel, tension steel, and cost. The constraints are steel ratios, ultimate moment of resistance, maximum and minimum area of reinforcements while materials costs are considered as the objective function. It is demonstrated that using the concrete compressive strength of 25MPa, simulated annealing can be used to optimize the design of concrete beams effectively. The results also indicate that the complications connected to the actual and genuine evaluation of costs of structures and the connectivity with the compulsory restraints can be adequately resolved using this method.
AN ENHANCED MULTIMODAL BIOMETRIC SYSTEM BASED ON CONVOLUTIONAL NEURAL NETWORK
LAWRENCE OMOTOSHO(1), IBRAHIM OGUNDOYIN(1), OLAJIDE ADEBAYO(1), JOSHUA OYENIYI(*1)
Multimodal biometric system combines more than one biometric modality into a single method in order, to overcome the limitations of unimodal biometrics system. In multimodal biometrics system, the utilization of different algorithms for feature extraction, fusion at feature level and classification often to complexity and make fused biometrics features larger in dimensions. In this paper, we developed a face-iris multimodal biometric recognition system based on convolutional neural network for feature extraction, fusion at feature level, training and matching to reduce dimensionality, error rate and improve the recognition accuracy suitable for an access control. Convolutional Neural Network is based on deep supervised learning model and was employed for training, classification, and testing of the system. The images are preprocessed to a standard normalization and then flow into couples of convolutional layers. The developed multimodal biometrics system was evaluated on a dataset of 700 iris and facial images, the training database contain 600 iris and face images, 100 iris and face images were used for testing. Experimental result shows that at the learning rate of 0.0001, the multimodal system has a performance recognition accuracy (RA) of 98.33% and equal error rate (ERR) of 0.0006%.
A REAL TIME FACE RECOGNITION SYSTEM USING ALEXNET DEEP CONVOLUTIONAL NETWORK TRANSFER LEARNING MODEL
LAWRENCE O. OMOTOSHO(1), IBRAHIM K. OGUNDOYIN(1), JOSHUA O. OYENIYI(*1), OLUWASHINA A. OYENIRAN(2)
In the field of deep learning, facial recognition belongs to the computer vision category. In various applications such as access control system, security, attendance management etc., it has been widely used for authentication and identification purposes. In deep learning, transfer learning is a method of using a neural network model that is first trained on a problem similar to the problem that is being solved. The most commonly used face recognition methods are mainly based on template matching, geometric features based, algebraic and deep learning method. The advantage of template matching is that it is easy to implement, and the disadvantage is that it is difficult to deal with the pose and scale changes effectively. The most important issue, regardless of the method used in the face recognition system, is dimensionality and computational complexity, especially when operating on large databases. In this paper, we applied a transfer learning model based on AlexNet Deep convolutional network to develop a real time face recognition system that has a good robustness to face pose and illumination, reduce dimensionality, complexity and improved recognition accuracy. The system has a recognition accuracy of 98.95 %.
TRANSFER LEARNING BASED OFFLINE YORÙBÁ HANDWRITTEN CHARACTER RECOGNITION SYSTEM
OLUWASHINA OYENIRAN(*1), EBENEZER OYEBODE(1)
This study presents Transfer Learning-based framework through the use of AlexNet for the development of an offline Yorùbá Handwritten Character Recognition System. The system encompasses the upper and case characters of the Yorùbá language, and tonal letters that have a significant impact on the Yorùbá language. The model reported network accuracy of 82.8%, validation accuracy of 77.7%, with F1 score of 0.7795, precision of 0.7819 and Recall of 0.7771. While the average recognition time is estimated to 0.371372 seconds. Thus, the technique of deep learning has shown significant improvement when compared to other existing approaches in recognizing standard Yorùbá characters.
COMPARATIVE ANALYSIS OF THE WASTE MANAGEMENT SYSTEM EFFICIENCY IN SOME COUNTIES FROM ROMANIA AND POLAND
OANA TIRTOACA [IRIMIA](1), PRZYDATEK GRZEGORZ(*2)
In recent years, technology and innovation have also reached the field of waste. They provide an excellent opportunity to improve policies aimed at minimizing waste generation and achieving resource efficiency. However, the degree of introduction of innovative equipment and practices varies significantly from one territory to another. The comparative analysis carried out on within 5 years, showed noticeable changes in the counties in Romania and Poland initiated by the EU and national legislation which indicated an increase in the amount of waste recovered. However, the achieved efficiency of limiting the deposited waste was different at the level of exceeding 70 % and higher of 0.10 kg an average indicator of waste accumulation per capita in Bacau County. Two counties mainly difference composition of municipal waste with predominance of biodegradable waste (60 %) in Bacau County and glass waste (35 %) in Nowy Sącz County with raw material properties. Differences were also noticeable in the case of hygiene fees with exceed of average value 20 EUR in Nowy Sącz County. The gradual increase in the amount of recycled waste and covering all residents with hygiene services should be considered beneficial which indicates an improvement in environmental awareness.
GENERATION OF DECELERATION PULSES OF THE TROLLEY IN CHILD RESTRAINT SYSTEMS’ DYNAMIC TESTS BASED ON SIMULATIONS AND EXPERIMENTAL VALIDATIONS
ZHE WEI(*1)
As one of devices for passive safety, child restraint system remains a positive factor in securing the safety of child occupants in vehicles’ collisions. Generation of deceleration pulses is essential for dynamic tests conducted to assess the safety performance according to many regulations such as UN Regulation No. 44. It deserves research on how to generate the qualified pulses conveniently and with low cost. A new method of convenience using steel pipes or tubes is recommended after all the factors influencing the deceleration being ascertained. Varied combinations of parameters make it possible and easy to optimize the deceleration pulses.