Systems Engineering- Staff Publications

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    Open Access
    Acoustic Pressure Waves in Vibrating 3-D Laminated Beam-Plate Enclosures
    (Advances in Acoustics and Vibration in Hindawi Publishing Corporation, 2009) Osheku, C.A.; Olunloyo, V.O.; Damisa, O.; Akano, T.T.
    The effect of structural vibration on the propagation of acoustic pressure waves through a cantilevered 3-D laminated beam-plate enclosure is investigated analytically. For this problem, a set of well-posed partial differential equations governing the vibroacoustic wave interaction phenomenon are formulated and matched for the various vibrating boundary surfaces. By employing integral transforms, a closed form analytical expression is computed suitable for vibroacoustic modeling, design analysis, and general aerospace defensive applications. The closed-form expression takes the form of a kernel of polynomials for acoustic pressure waves showing the influence of linear interface pressure variation across the axes of vibrating boundary surfaces. Simulated results demonstrate how the mode shapes and the associated natural frequencies can be easily computed. It is shown in this paper that acoustic pressure waves propagation are dynamically stable through laminated enclosures with progressive decrement in interfacial pressure distribution under the influence of high excitation frequencies irrespective of whether the induced flow is subsonic, sonic, supersonic, or hypersonic. Hence, in practice, dynamic stability of hypersonic aircrafts or jet airplanes can be further enhanced by replacing their noise transmission systems with laminated enclosures.
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    Open Access
    An Approach for Critical Evaluation of Examination Questions in an Engineering Faculty Using the Classical Bloom Taxonomy
    (Nigerian Journal of Technology, 2018) Ogunwolu, L.; Ajibola, O.E.; Sosimi, A.
    Ideally, teaching curricula are designed to exude some learning behavioural outcomes in students. When students are examined through oral, practical and or theoretical evaluation schemes in examinations, the primary objective is to measure the relative extent to which students can exude the desired behavioural outcomes. Thus it is important that appropriate means and expressions are employed in assessment to measure learning. Based on an average-occurrence-rating scale, a set of Action verbs of the classical Bloom’s taxonomy were used in this study in assessing the level of learning outcomes required in each of 21 Engineering Core Course examination-questions used. Rates were computed for Knowledge, Comprehension, Application, Analysis, Synthesis and Evaluation levels of the Bloom’s Taxonomy. Marginalized One-Factor Statistical experiments and randomized two-factor Statistical experiments were designed using the rates computed. Analysis of Variance (ANOVA) technique was used to test within- and between-treatments variations of the differences of means for the six Bloom’s taxonomy levels using hypotheses at 0.05 levels of significance for each of the experimental design scenarios. Analyzed results show significant differences in course ratings at different Bloom taxonomy levels and significances in differences in ratings of the taxonomy for different courses. Group tests of hypotheses on differences of mean-ratings for the courses show significance. The study brings to light the need for examiners in these courses to put more effort in upper levels of behavioural outcomes especially on Synthesis and Evaluation which are germane for training of good Engineers.
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    Open Access
    Arrival Patterns and Traffic Flow Characteristics at Signalized Intersections: Considering Upstream Signal Influence and Time Resolutions
    (FUTA Journal of Engineering and Engineering Technology, 2021) Akinfala, O.O; Ege, E.E; Ogunwolu, L.F.
    Traffic arrivals at signal intersection approaches is inherently stochastic. This variability is typically reflected by I-ratio and there is a general consensus that the presence or absence of nearby upstream signal affects Variance to Mean Ratio (I-ratio). However, the effect of time resolution on arrival variability and the interaction effect between upstream signal and time resolution is yet to be examined in detail. This can lead to model misspecification and invariably, erroneous outcomes. This work examines the effect of time resolution and intersection type and their interaction on I-ratio and the resultant probability distributions. Traffic arrivals were measured at high time resolution- 10 seconds interval and then aggregated to lower time resolutions (30-150 seconds) at six intersections. Spectral density analysis showed statistically significant periodicity, specifically at 30 seconds interval with p-values < 0.0001 at all connected intersections while observations at isolated intersections lacked periodicity. Two-way ANOVA using I- ratio as the dependent variable and intersection type and time-resolution as the independent variables was performed. Statistically significant effect with F-value 8.606 at p-value < 0.0001 and R2 value 0.32 were observed. Intersection type, time resolution and the interaction between them were statistically significant, with p-values 0.002, < 0.0001 and 0.000 respectively. The combined effect of these factors led to a wide I-ratio range oJ’0.37-9.2. Negative Binomial, Poisson, and Binomial distributions represented 76.4, 20.4 and 4.2% of all I-ratios observed. Therefore, in contrast to literature which recommends Poisson, Negative Binomial may be a better suited probability distribution for traffic arrivals.
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    Open Access
    Assessment of Home-Based Nigerian Engineers on Risk Management Approach during Project Implementation
    (Journal of Applied Sciences and Environmental Management, 2018) Ajibola, O.O.E.; Omiyale, A.D.; Ogunwolu, L.
    The objectives of this paper are to identify possible gaps in identification, evaluation, analysis, implementation and effectiveness of risk management approaches among home-based consulting Engineers in Nigeria vis-à-vis the implementation of such practices. Structured Questionnaire method was adopted as the survey instrument to collect data centred on issues on the subject matters. Out of 80 questionnaires distributed, 61 were returned and 6 of the returned responses rendered invalid leaving 55 valid questionnaires. The Analysis of Variance (ANOVA) and Correlation methods were adopted for statistical analysis with respect to which four hypotheses based on the subject matter were formulated and evaluated using the F-and Correlation statistics. The first premised on risk identification resulted in comparative F-statistics of Fcrit = 0.057592 < Fcrit = 2.866081, the second on risk evaluation yielded Fcrit = 0.194683 < Fcrit = 2.866081 while the third based on risk management implementation resulted in Fcrit = 0.093474 < Fcrit = 2.866081. The results of the first three hypothesis indicted the home-based Consulting Engineers of not identifying, analysing/evaluating and implementing risk management approaches in project execution respectively. The fourth hypothesis premised on correlation between management approach and policy implementation yielded a correlation statistics of 0.501642 establishing a positive correlation between the two among the home-based Consulting Engineers. The study thus establishes risk management practices as key to successful project management and its neglect as major causal factor for project failures in Nigeria.
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    Open Access
    Conceptual and Simulated Semi-Automatic Urban Waste Management System using Global Systems for Mobile Communication and Customer Reliability Indices
    (Journal of Applied Sciences and Environmental Management, 2019) Ogunwolu, L.; Omiyale, A.D.; Ajibola, O.O.E.
    Municipal Solid Waste Management (MSWM) poses great challenges to many cities around the world. The challenges are fuelled by population explosions all over the world, especially in the major urban centres, against the backdrop of limited resources to manage wastes efficiently. In this paper, a conceptual and simulated semi-automatic approach to MSWM is considered using the prevalent Global Systems for Mobile Communication (GSM) technology to engage both the waste generators and collectors. This system connects users into a central database where data about their waste bin levels are harnessed. Users are prompted via GSM handsets daily for the level of the waste bin. Waste Collection Vehicles are routed based on the responses while an updatable Reporting Reliability Index (RRI) is computed for each user based on estimate of actual level of waste collected as against the reported level to factor future reporting. With history of collection volume at a location known, forecast is made as to the generated waste level when a customer’s response to prompt is not available. The system is tested on a simulated 30-node housing estate and two dump sites with vehicles routed to optimize distance covered and volume of waste collected. Customers report when prompted with 0, 1, 2, 3, 4 for waste levels ranging from empty to full bin fills. Vehicles are routed to collect wastes at locations with a minimum threshold level of 2. Results obtained showed statistically insignificant differences in distribution of means of collection distance covered weekly but 13.31 volume units/km collected with this method compared with 3.08 volume units/km run of fixed routing scheme, at alpha = 0.05. The cost saving potential and environmental benefits of timely waste disposal of this scheme is thus demonstrable.
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    Open Access
    A Conceptual E-Control Approach to the Resolution of Apapa Traffic Gridlock
    (Innovations and Advances in Emerging Technologies. Festschrift Publication in Honour of Professor Oye Ibidapo-Obe., 2020) Ibidapo-Obe, O; Sosimi, A.A.; Ogunwolu, L.
    The Apapa traffic gridlock occasioned by articulated lorry movement for logistic services on the corridor has posed almost intractable traffic challenges over the years. A conceptual electronic-control approach to the corridor traffic management presented here is the bedrock of an on-going intensive simulation study to establish the efficacy of the approach. In this electronic concept, a central control station is connected to four parking zones on the outskirt of Lagos linking Ibadan, Abeokuta, Epe and Sagamu/Ijebu-Ode and other internal Transit Parks doubling as parks and check points for trucks inbound Lagos and Apapa business corridor. Information on available parking spaces on cargo and fuel lifting bookings, available parking spaces and serviced vehicles details are made available real time from Cargo freight agencies and distributors and petroleum Tank Farms. This presentation is based on three-tiers of e-control measures at the Transit Park/Control Points, Within Traffic Network and at Enrolled Destination levels. With effective implementation and enforcement this e-control measure will sanitize the Apapa traffic corridor and its adjoining areas.
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    Open Access
    A Decision Support Model and Analysis for Aircraft Maintenance Planning
    (International journal of Mathematics Analysis and Optimization: Theory and Application, 2015) Ogunwolu, L.; Popoola, O.P.; Ibeh, S. C.
    Aircraft maintenance planning and scheduling is a major decision airline operators must make. If properly done, this can result in huge cost savings and high productivity. Maintenance downtime (from daily inspections, component replacements and different types of scheduled checks) is a key operational bottleneck that must be minimized while maintaining aircraft for safety and reliability. This paper provides a planning model which determines the optimal solutions to aircraft maintenance planning and scheduling using a Non-Linear Pure Binary Mathematical Program solved using the Evolutionary Algorithm search engine of the Excel Solver. Results obtained using data from an actual airline for the proposed model and heuristic results in a higher likelihood of meeting operational flight schedule at relatively minimized overall downtime. There is an optimal balance between constraints set by irregular component failures, regulatory maintenance requirements and the anticipatory expectations of meeting projected flight schedule over a given period operation.
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    Open Access
    Design and Implementation of an IoT Based Smart Waste Bin for Fill Level and Biodegradability Monitoring
    (Journal of Engineering Research, 2020) Ogunwolu, L; Mbom, H.; Raji, A.; Omiyale, A.
    Effective and efficient waste management is a critical component of a smart city. Worldwide, waste management has proved to be a daunting task for bodies assigned with the task. Waste overflow and the menace of degradable wastes as they affect communal health and environmental aesthetics are key challenges faced by waste managers. This paper addresses these challenges with the design and implementation of an Internet of Things (IoT) based Smart Waste Bin that tracks in real time the volume and smell (biodegradability) of the waste in it and alerts the waste managers once the set threshold for volume or smell is reached. An Ultrasonic distance sensor HRSO4 and MQ series semiconductor gas sensors MQ4 and MQ135 connected on an Arduino UNO R3 microcontroller board were deployed for fill level and biodegradability sensing respectively. The status of the bin is communicated to a ThingSpeak webserver via an ESP8266 Wi-Fi module interfaced with the microcontroller in real time. Through this, Waste Managers can be alerted to evacuate the waste before it starts overflowing or the smell becomes offensive. The bin was tested with non-biodegradable and biodegradable waste composed of waste mixed with fowl and pig dung. In the experiment, the biodegradability sensor readings remained constant while the ultrasonic distance sensor reading gradually decreased over time as the non-biodegradable waste filled the bin. On the other hand, all sensors responded with varying degrees when waste mixed with either of the dung types filled the bin. The results vindicated the purpose of the design and implementation
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    Open Access
    An Ergonomic Critique and Redesign of a Local Cane Chair in Nigeria with User Body Mass Index. ABUA
    (ABUAD Journal of Engineering Research and Development (AJERD), 2018) Ogunwolu, L.; Popoola, O.P.; Sosimi, A. A.; Raheem, W. A.
    Furniture is designed to satisfy anthropometrical demands of proposed users and to meet intended usage. The comfort and functional utilities of the furniture depend on its physical design in relation to the physical structure and biomechanics of the human body. In this work, the design of a locally manufactured cane chair in Nigeria was critiqued with the goal of providing more ergonomic designs to satisfy both anthropometrical needs and the design goals. A novel combination of qualitative and quantitative design criteria was used in an experimental setting involving 1,000 user assessors of varying body weights and heights to criticize the design and construction of the local cane chair. Analyses of results of measurements and interviews show discrepancies in standard design parameters and the design features of the cane chair with different Body Mass Indices (BMI). Using a multi-evaluation functional design approach and two novel design criteria, alternative designs were proposed based on analyzed results for different anthropometrical measures. The results were analyzed in relation to human body mass indices, which are health indicators for various health issues including those occasioned by seating. The work demonstrated a balanced approach using both qualitative and quantitative parameters to assess and influence the redesign of a chair in an experimental setting.
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    Open Access
    A Linguistic Fuzzy Expert System for Contagious Diseases Detection and Isolation
    (UNILAG Journal of Medicine, Science and Technology, 2014) Osigbemeh, M.S.; Ogunwolu, F.O.; Omoare, A.A.; Inyiama, H.C.
    This paper presents an electronic Expert system platform to detect and diagnose existing and new cases of contagious diseases as they occur with minimal contact with the index patient(s) and healthcare personnel with a confidence level that can be used to initiate or suggest appropriate follow-up action(s). The aim is to use ICT tools for patient-diagnosis, raise a red flag in real-time and thus contain contagious cases which may degenerate into an epidemic by providing a way to analyze vague and ambiguous input data from visible and reported symptoms in patients. A re-useable Expert system which makes use of fuzzy reasoning techniques and design methodology was used in this work. The Expert system is premised on rule-based fuzzy logic which captures the ambiguity, imprecision and nuances involved in disease reporting and detection using the Mamdani model. The software developed for the Fuzzy Expert system, called SOSIC, presents its diagnosis with fuzzy values between 0 to 1 corresponding to its level of confidence for the fuzzy inputs. The current approach to e-diagnosis and detection of contagious diseases using the SOSIC software is not completely contactless, thus ongoing investigations are geared towards improving SOSIC to be contactless. The developed system which runs on a computer system provides a safe procedure with minimum contact between patients and healthcare personnel to address early detection and diagnosis issues that may help forestall chain-infection and epidemics. The fuzzy based Expert system can be further extended to accommodate the detection of a wider array of symptoms as new cases arise; thus this paper fulfils an identified need in safe healthcare practice.
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    Open Access
    Modeling and Optimization of an Electric Power Distribution Network Planning System Using Mixed Binary Integer Programming
    (Nigerian Journal of Technology, 2017) Ogunwolu, L.; Ero, O.; Ibidapo-Obe, O.
    In this paper, the electric distribution network expansion planning problem (EDNEPP) was solved by a mixed binary integer programming (MBIP) formulation of the network, where the steady-state operation of the network was modelled with non-linear mathematical expressions. The non-linear terms are linearized, using piecewise linearization of the nonlinear expressions, so as to ensure the model computational compatibility with existing commercial optimization solvers. The linearized formulation is verified to ensure its solution optimality and degree of error deviation. The proposed network model formulation considers the alternatives of installation of new transformers of various capacities to reinforce already existing ones at substations of the network, choosing and construction of new substations given feasible locations, re-conductoring of existing feeders in the network, construction of new feeders given various conductor types alternatives, cost lost as a result of power interruption, and changes in the overall network topology. The cost of interruption would contain a cost term called ‘cost of goodwill’, which was brought into the model formulation, to measure the loss in confidence of consumers to distributors of power as a result of interrupted power supply, which is prevalent in developing nations. Two test systems of 23 and 54 nodes was used in showing the efficiency of the proposed network model formulation.
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    Open Access
    Modelling Gait Syndrome in Huntington's Disease: The Genetic Algorithm Approach
    (Nigerian Journal of Technology, 2017) Ajibola, O.O.E.; Ogunwolu, L.
    Huntington’s disease (HD) which usually affects the patients at middle age results from malfunctioning of the basal ganglia. It is characterized by cognitive impairment, involuntary movements, neuropsychiatric and psychological disturbances. Early motor signs of Huntington’s disease typically include the gradual onset of clumsiness, balance difficulties, and brief, random, fidgeting movements. A popular approach to solving symptoms arising from HD has been through the administration of drugs. But drugs debase human activities, thus the application of electroconvulsive therapy. This work proposes a genetic algorithmic (GA) simulation of chorea in HD patient as a pedestal for the design of a therapeutic device aimed at managing the phenomenon. Earlier efforts have led us to the formulation of such models in recent past. We also compared the GA model with our foremost effort: the electromechanical model, and we observe that the GA model adequately capture the physiological presentation of gait phenomenon in Huntington’s disease.
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    Open Access
    Modelling. Optimization and Analysis of Re-Entrant Flowshop Job Scheduling with Fuzzy Processing Times
    (Nigerian Journal of Technology, 2017) Ogunwolu, L.; Sosimi, A.; Obialo, S.
    This paper presents a makespan minimization of -jobs -machines re-entrant flow shop scheduling problem (RFSP) under fuzzy uncertainties using Genetic Algorithm. The RFSP objective is formulated as a mathematical programme constrained by number of jobs and resources availability with traditional scheduling policies of First Come First Serve (FCFS) and the First Buffer First Serve (FBFS). Jobs processing times were specified by fuzzy numbers and modelled using triangular membership function representations. The modified centroid defuzzification technique was used at different alpha-cuts to obtain fuzzy processing times (FPT) of jobs to explore the importance of uncertainty. The traditional GA schemes and operators were used together with roulette wheel algorithm without elitism in the selection process based on job fuzzy completion times. A test problem of five jobs with specified Job Processing and Transit Times between service centres, Job Start Times and Job Due times was posed. Results obtained using the deterministic and fuzzy processing times were compared for the two different scheduling policies, FCFS and FBFS. The deterministic optimal makespan for FBFS schedule was 61.2% in excess of the FCFS policy schedule. The results also show that schedules with fuzzy uncertainty processing times provides shorter makespans than those for deterministic processing times and those under FCFS performing better than those under FBFS policy for early jobs while on the long run the FBFS policy performs better. The results underscore the need to take account of comprehensive fuzzy uncertainties in job processing times as a trade-off between time and costs influenced by production makespan.
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    Open Access
    A Multi-objective Resource-constrained Project Scheduling Problem Using Genetic Algorithm
    (2018) Ogunwolu, L.; Sosimi, A.A.; Salahudeen, T.
    Resource-Constrained Project Scheduling Problem (RCPSP) has been modeled as a single or multi-objectives, using minimization of project make-span, lateness, total weighted start time, total project cost and maximization of project net present value. In this paper, a multi-objective RCPSP incorporated resource idleness into the list of RCPSP objectives. Here, the RCPSP is modeled as a Mixed Integer Non-Linear Programme to depict the various objective factors namely cost, time and resource idleness. Genetic algorithm (GA) meta-heuristic solution technique is used to promote solution diversity and determine the Pareto optimal for the multi-objective problem. The performance of the proposed RCPSP model was evaluated using a standard test problem that consist of 5 activities, 3 reusable resource types and a network diagram; a comprehensive computational experiment was performed and the results were analyzed with precedence relations considering the objectives as single objectives, bi-objectives and in combined form as multi-objectives simultaneously. The integration of resources idleness into the multi-objective policy gives more realistic result.
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    Open Access
    Optimal Routing for Automated Emergency Vehicle Response for Incident Intervention in a Traffic Network
    (Journal of Applied Sciences and Environmental Management, 2018) Ogunwolu, L.; Sosimi, A.; Jagun, O.; Onyedikam, C.
    Congestion constitutes a major problem in modern urban traffic networks if not well managed. Its monstrous effects, on occasions, can paralyze a traffic network eating deep into the productive hours of commuters as well as vehicles and persons on essential services. Particularly affected are incidence-intervention vehicles such as emergency vehicles and fire-fighting vehicles. Whatever the cause of the congestion, its effect is counter-productive and an indication of an inefficient traffic network. This work, as presented in this paper, is concerned about the issue of traffic route management for emergency service (emergency vehicle) for which a delay of few minutes may cause tremendous loss of lives and properties. The route management scheme built for this purpose integrates information obtained from the use of Radio Frequency Signals for Traffic Light Preemption at Intersections in a Proteus Simulator environment and the use Arc GIS as a mode of routing the emergency vehicle from base to the incidence location, then to Health Facilities and from thence back to the emergency vehicle base in an optimal routing time. Traffic information are loaded into the Arc GIS environment which predicts the required tri-legged optimal routing and its duration using Dijkstra’s algorithm. Different scenarios of emergency vehicle, incidence and health facility locations were exploited using the scheme and compared with situations without their implementation. The proposed scheme outperforms the trial and error routing of emergency vehicles and can be embedded into traffic advisory system or as stand-alone emergency vehicle management system.
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    Open Access
    An Optimized Telecommunication System Topology for Expenditure Minimization and Improved Spectral Utilization Efficiency
    (FUNAI Journal of Science and Technology, 2015) Ogunwolu, L.; Ibidapo-Obe, O.; Adeyemi, T.
    Capital expenditures (CAPEX) and Operational Expenditure (OPEX) have always been on the high side if transmission networks are not efficiently planned to minimize these costs. The arrays of antenna often sighted on mast/tower around often post a major risk to the industry as CAPEX increases with increased hardware and signal processing cost. This paper explores the use of point to multipoint (PMP) method of backhauling traffic for cognitive radio network as veritable alternative to existing transmission Point to Point (PTP) Topology in other to minimize CAPEX and OPEX as well as improve spectra utilization efficiency. The work is focused on small cell deployment for more data penetration in a redundant setup to improve system availability. In the work, the Dijkstra Algorithm for Shortest route analysis was used to prove the advantage of Point to multi point approach in the optimal path planning in a transmission network taking cognizance of path costs as the capital expenditure, path loss, latency, throughput, frequency channel allocation. Furthermore, a spectrum utilization problem was defined, formulated and analyzed. Solution of this model was validated using a simulated setup on a section of Ikorodu ( and ) transmission axis. Results obtained from the analysis show that our model of PMP method of transmitting/backhauling is more capable of improving the spectral efficiency of a wireless telecommunication network and outperforms the PTP topology on all network measures influencing capital and operational expenditures.
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    Open Access
    Performance Appraisal of the Traffic Intersection Complex at Mokola, Ibadan, Nigeria
    (Journal of Applied Sciences and Environmental Management, 2019) Oyedepo, O.J.; Ogunwolu, L.; Akinfala, L.
    Throughput time reduction is an integral part of transportation benefit analysis and traffic engineering optimization objectives. It is for this reason, that a large majority of transportation projects view throughput time reduction as one of their principal objectives. An appraisal of the performance of a traffic intersection complex at Mokola, Ibadan, Nigeria using a conflict intensity approach is presented. This work was carried out in order to quantify the effects of the flyover on the reduction of throughput times of vehicular traffic at the intersection. Conflict intensities were measured through traffic volume counts at various conflict points (through, merging and diverging locations). A floating vehicle equipped with a GPS was adopted to capture throughput times through several trial runs at the intersection. Statistical relationships were established between conflict intensities and throughput times using regression analysis. These relationships served as a framework for simulation for generating travel times (augmented), assuming the absence of a flyover. The results show a statistically significant reduction in throughput times due to the presence of the flyover with p-value of < 0.0001 at alpha level of 0.05 using Wilcoxon-Signed rank test. Specifically, reductions of 40.2seconds (33%) for northbound traffic and 27.6 seconds (28.8%) for southbound traffic were observed. This work has shown that the flyover reduced throughput times. The construction of the flyover is therefore justified and its residual potentials are enormous to handle traffic growth in the area in the near future.
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    Open Access
    Process Capability Analysis in a Polypropylene Bag Manufacturing Company
    (Journal of Applied Sciences and Environmental Management, 2021) Odeyinka, O.F; Ogunwolu, F.O.; Popoola, O.P.; Oyedokun, T.O.
    Process capability analysis combines statistical tools and control charts with good engineering judgment to interpret and analyze the data representing a process. This work analyzes the process capability of a polypropylene bag producing company. The case study organization uses two plants for production and data was collected over a period of nine months for this study. Analysis showed that the output spread of plant 1 was greater than the specification interval spread which implies poor capability. There are non-conforming parts below the Lower Specification Limit (LSL: 500,000 metres) and above the Upper Specification Limit (USL: 600,000 metres) and that the output requires improvement. Similarly, the capability analysis of plant 2 shows that the overall output spread is greater than the specification interval spread (poor capability). The output centre in the specification and overall interval are vertically aligned, thus specifying that the output from plant 2 is also process centered and requires improvement. Recommendations were made to improve the outputs from each production plant.
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    Open Access
    Queue Discharge Headway: Characteristics, Distributions and Effects on Saturation Flow Rates at Selected Signalized Intersections in Lagos
    (International Journal for Traffic and Transport Engineering, Belgrade, 2022-01) Akinfala, Olanrewaju; Ogunwolu, Folorunso; Ege, Emmanuel
    Saturation flow rate (SFR) and headway are highly localized essential parameters for accurate and effective performance analysis and optimization of signalized intersections. This study examined the saturation flow rate (SFR) and characterized headways at eight signalized intersection approaches, six of which were ideal while two were typical approaches of Lagos conditions. Over 700 cycle to cycle headway data was collected and analyses such as Fuzzy level 1; statistical tests such as Wilcoxon-Signed rank, Mann-Whitney and ShapiroWilks tests were performed on the observed headways. The average SFR observed for ideal approaches was 1,927 veh/hr/lane which is higher than values observed in many developed countries, while at typical approaches, it was 1,342 veh/hr/lane. Statistically, SFR differed significantly during peak and off-peak periods (230 veh/hr/lane) and at ideal and typical approaches (between 460-750 veh/hr/lane). Across all traffic conditions observed, the Burr group of distributions were the overall best fit for modelling headways. A fuzzy-based SFR of 1,789 veh/hr/lane was proposed. This study shows that indeed, headway and SFR differ considerably spatiotemporally. Therefore, appropriate SFR and headway values which reflect actual operating conditions must be adopted to ensure optimal operational performance at signalized intersections.
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    Open Access
    A Review of Lean Manufacturing, Six Sigma and Lean Six Sigma
    (The Pacific Journal of Science and Technology, 2021) Ogunwolu, Folorunso O.; Odeyinka, Olumide F.
    Lean manufacturing and Six Sigma are quality techniques used by organizations to meet production targets, enforce standards, reduce waste, and ensure continuous flow of products. While the Lean approach focuses on waste elimination, Six Sigma emphasizes reduction of process variation. This work is an overview of these tools. It gives the history and methodology of Lean and Six Sigma. It also highlights several applications of both methodologies in diverse fields of endeavors.