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Enhancements of online adaptive lyapunov-based observer for state of charge estimation of lithium-ion batteries
Full text linkOwing to the rapid growth of electric vehicles (EV), temporary energy storage and mobile applications, the battery management system (BMS) plays an indispensable role in ensuring the safety, efficiency, and longevity of the battery. To achieve these features, the state of charge (SOC) estimation algorithm must be enhanced. Since the BMS processor repeatedly executes the SOC for a massive number of cells, the algorithm must be computationally simple, efficient, and accurate. The online estimation of lithium-ion SOC using the recently published adaptive Lyapunov-based observer is an attractive proposition due to the stability, adaptability, and reduced computing requirements. However, the observer requires the presence of persistent excitation (PE) to guarantee the convergence of the battery model parameters to their correct values. Although several important works have utilized this observer, they only apply dc excitation—which implies that the PE condition was never met. Thus, one objective of this thesis is to modify the observer so that it can be used to estimate the SOC for the dc and low excitation signals. Furthermore, there is insufficient work in the literature that demonstrates the application of the observer to estimate the SOC for EV. The motivation is the possibility of capitalizing on the EV driving profiles' inherent sufficiently rich (SR) signals to satisfy the PE condition. The performance of the SOC algorithm based on the proposed online observer is simulated on MATLAB/Simulink. Furthermore, the experimental validations are done at room temperature for a 3 Ah single cell of type Lithium Nickel Manganese Cobalt oxide (NMC). The algorithm is tested using dynamic stress test (DST) and real EV driving profiles, namely the supplemental federal test procedure (US06) and the federal urban driving schedule (FUDS). The performance of the observer is compared to the extended Kalman filter-recursive least squares (EKF-RLS). The proposed scheme requires 2.5 times less computational effort while retaining similar degree of accuracy to the latter. In addition, to fulfil the PE condition at low current excitation, a method called forced excitation is proposed. The SR signals are generated by chopping the battery current at a certain rate for a specific interval. The simulation and experimental results showed that the forced excitation method enables the observer to estimate the SOC reliably under dc condition. In addition, a simple scheme using a supercapacitor to compensate for the interruption in battery current and deliver continuous current to the load is suggested. It is envisaged that the proposed observer can contribute to the design of a customized and high performance BMS for many applications
Innovation business model development for public sector towards innovation policy implementation in Malaysia
Full text linkSince 2009, a substantial focus has been given to innovation through transformation agenda, which has resulted in strategic moves in policy and nationwide initiatives. This approach for improvement involves a change in public sector organisations, policy, and service delivery, implicating a huge number of resources and high failure risk. Such impacts influence international report monitoring and ranking among nations, especially in innovation. As the Malaysian Public Sector innovation landscape remains an understudied field together with an absence of measurement instrument and organisation-level innovation model, the drawback poses a tremendous risk towards innovation policy implementation. The aim of this research is to propose an Innovation Business Model for innovation policy implementation and reduce the empirical research gap in the public sector innovation knowledge base. This research examines the innovation landscape in the Malaysian public sector and its impact towards public sector organisation innovation performance through innovation capabilities and innovation management from a Business Model Perspective for contemporary model development. The current innovation business models in organisations were measured through quantitative research using the Structural Equation Modelling technique model to evaluate the impact towards overall organisation innovation performance. This research involves a sample size of 328 public sector middle managers selected by stratified random sampling, and a survey questionnaire as the research instrument. As hypothesised, Malaysian Public Sector innovation landscape was found to be dependent on innovation capabilities, both as a factor and mediator in influencing innovation performance. It was discovered that there is a dire need for an organisation-level model to balance the dependency and improve the innovation performance in public sector agencies by focusing on both innovation capabilities and innovation management. The contribution of this research is in developing an organisation-level Innovation Business Model within the Malaysian setting. Ultimately, the public sector can capitalise on implementing innovation and enhance organisational performance in both practical and the academia through the expansion of public sector literature in the Malaysian context. This motion can be accomplished through its Innovation Business Model development and the accompanying rediscovered measurement instrument
The influence of online social networking behaviour towards academic performance of designated secondary school students in Klang Valley
No full textRecent statistics indicate that the utilization of Online Social Networking among Malaysian youngsters is increasing exponentially. These youngsters who predominantly are students, use Online Social Networking daily. This recent trend is now often accompanied by parental worry of potential negative impact of Online Social Networking which may be detrimental to their children’s academic performance. Even though there are numerous literature related to Online Social Networking, there are limited research on Online Social Networking behaviour and its relation to academic performance especially in the context of Malaysian secondary school students. Most studies on Online Social Networking behaviour were conducted at tertiary level and concentrated on developed countries in the West. Hence, this study investigated the Online Social Networking behaviour and its relation to academic performance among secondary school students. The conceptual framework is based on Unified Theory of Acceptance and Use of Technology on Students (UTAUTS) and ‘ACADEMIC’ variables synthesized from the literature. The incorporation of ‘ACADEMIC’ to the UTAUTS framework to study the impact of students’ academic performance is new. A survey was conducted on 247 students from selected six secondary schools in Klang Valley. The study identified four crucial factors that influence students’ adoption and use behaviour of Online Social Networking: performance expectancy, effort expectancy, social influence, and facilitating condition. The results showed positive and significant relationships among all the factors. On the impact of Online Social Networking with academic performance, the result showed that the adoption and use of Online Social Networking is positively correlated with the students’ academic performance. The result indicated that the usage of Online Social Networking is vital in enhancing knowledge and social skills among students beyond the school setting, which helps to improve their academic performance. In sum, the findings of this study can be used to harness the benefits of Online Social Networking to enhance students’ learning experience
Multibeam dielectric lens antenna for 5g mobile base station
No full textThe introduction of fifth-generation (5G) mobile communication technology has new features such as millimetre wave operation, small cell size and multibeam base station antenna to meet massive multiple-input multiple-output (MIMO) requirements. The introduction of fifth-generation (5G) mobile communication technology has new features such as millimetre wave operation, small cell size and multibeam base station antenna to meet massive multiple-input multiple-output (MIMO) requirements. At millimetre wave, the base station antenna size is expected to be less than 30 cm, and aperture antennas such as the reflector and the dielectric lens antenna can be among the alternatives to replace the present array antenna. Based on previous works, the dielectric lens antenna was designed to produce excellent multibeam radiation patterns as compared to the reflector antenna. Many lens antennas have been reported for various applications such as airborne radar and vehicle’s collision avoidance system. For base station application, the lens antennas with small thickness and curvature are required for light weight and ease of installation. The main objective of this research is to propose a new lens design method for thin and small curvature antenna and ensure its multibeam characteristics. By developing the geometrical optics algorithm for lens shaping method in MATLAB software, the conventional Aperture Distribution Condition (ADC) and the Abbe’s Sine Condition (ASC) are designed to ensure the accuracy of the developed algorithm. In order to achieve the thin lens and small curvature structure, a newly proposed design method, namely Straight-Line Condition (SLC) lens at designed frequency of 28 GHz and material with dielectric constant, εr of 4 was developed. At the lens size of 10 cm antenna with ratio focal length-to-diameter, F/D=1, the SLC lens structure provides thickness of 1.38 cm as compared to ADC and ASC with thickness of 1.7 cm and 1.48 cm, respectively. Multibeam radiation patterns of ADC, ASC and SLC were compared by using electromagnetic simulator FEKO. Good multibeam radiation patterns for SLC is ensured for scanning beam angle from 0° to 42.6°. To determine the optimum feed positions for multibeam performances, the focal region ray tracing was conducted in receiving mode by the Ray Launching-Geometrical Optics (RL-GO) solver of FEKO simulator. New feed positions locus for SLC was obtained and compared to ADC and ASC. For the practical application to install base station pole, the cylindrical structure of SLC lens antenna was designed at the F/D ratio of 0.6 and polycarbonate material with dielectric constant, εr of 2.9 was selected. The practical size of cylindrical height of lens antenna is 20 cm and the cylinder diameter is 29 cm with thickness of about 5.13 cm. New feed position locus for SLC cylindrical structure was obtained at F/D ratio of 0.6. From the near field distribution, phase constant and adequate amplitude distribution on the aperture plane is ensured. Fan beam radiation pattern was produced for the cylindrical lens. In the vertical plane, multiple beams radiation pattern was achieved. The beamwidth of fan beam is 45° and vertical beam is 3.28° with maximum antenna gain of 22.98 dBi. Good multibeam radiation patterns are obtained for wide scanning beam ranging from 0° to 47.1° in the vertical plane. Gain reduction is 6.56 dBi. As a result, the new proposed of cylindrical SLC dielectric lens antenna is suitable for the use of 5G multibeam base station application
Multivariate time series modelling of taxes revenue in Nigeria
Full text linkTax is a source of revenue or income for a government to achieve a country’s macro economic objectives in the areas of fiscal and monetary policies. However, the effects of tax burden may cause economic recession, financial crises, as well as poor standard of living and economic hardship for the people. In order to tackle these challenges, there is a need for short-term, medium-term, and long-term periods of forecasting models to be developed. In general, financial time series forecasting models are not tax-revenue based-models. Thus, existing models are inadequate to gauge the relationship between tax-based variables that can be particularly volatile. This research bred a model that used data with distinguished variables, obtained from the bulletin of the National Bureau of Statistics and the Central Bank of Nigeria. In this study, Vector Autoregressive model (VAR) and the functional Generalized Autoregression Conditional Heteroscedasticity family (fGARCH) models were combined to consider the behaviour of the financial time series (tax revenue) data. However, because of the high persistence of volatility in the data, the GARCH family model alone is unable to capture the leverage effects in the structural changes of the time series. Hence, the Auto-regression Hidden Markov Model (ARHMM) was proposed to handle this issue. The results show that the VAR with the hybrid of fGARCH models were unable to capture the volatile behaviour of the tax revenue data. On the other hand, the proposed model that used the ARHMM to capture the intensity of volatility persistence performed better. The out-of-sample forecasting accuracy gave less than ten percent of the Mean Absolute Percentage Error (MAPE) for the proposed model. The simulation study has proven that the VARARHMMfGARCH proposed model produced better results as compared to the hybrid of the traditional VAR-fGARCH model. The newly joint VAR-ARHMM-fGARCH model offers an effective forecasting approach for future tax revenue data
Smart energy management system for common area in multi-tenant building
Full text linkIn recent years, energy management and efficiency in building became important concern in our country. Various technology and systems in energy management and efficiency aspect have been established in order to fulfill the needs for efficient energy and towards lower carbon footprint. However, energy management in multi-tenant building like apartment and other high-rise building seen less effective in energy management. Currently, most of this building management conduct energy management manually without any efficient control system in order to monitor and control energy consumption for optimal efficiency. Energy consumption by tenants is directly impact to overall building consumption but the building management cannot see the pattern of the tenant’s consumption. As a result, the energy consumption and efficiency cannot be managed by the building management efficiently. Thus, this research will study about the potential of smart energy management system, system design and its implementation in multi-tenant building as on effort to control and increase energy efficiency as well as its potential economic impact. Finding, result and solutions based on the developed model of the smart energy management system are also being discussed as to establish a clear picture on potential economic impact from the application of smart energy management system into multi-tenant building
Non-orthogonal multiple access for cellular-connected unmanned aerial vehicles
Full text linkCellular-connected unmanned aerial vehicles (UAVs) have been introduced for 5th Generation (5G) and beyond cellular networks to enable various UAVs’ operations which require real-time and ubiquitous connectivity. Existing solutions are relying on orthogonal multiple access (OMA) to support existing terrestrial users (TUs) and UAVs as new aerial users (AUs). However, OMA is unable to provide an efficient network performance because each orthogonal resource block can only be utilised by a single user. To address this limitation, non-orthogonal multiple access (NOMA) can be employed. NOMA enables AUs and TUs to share the same orthogonal resource block. By leveraging their downlink asymmetry, NOMA could efficiently serve the AUs and TUs. Nevertheless, concurrently serving the AUs and TUs in cellular networks introduces new challenges. Specifically, reverse successive interference cancellation (SIC) policy and inappropriate NOMA power allocation might occur if the AUs are moving in three dimensional space and perfect channel state information (CSI) is unavailable. These issues will result in spectral inefficiency and unreliable communications. Due to high altitude, AUs also suffer strong inter-cell interference (ICI) that causes the pairing of AUs and TUs in NOMAto be inefficient. Therefore, this thesis investigates the performance of NOMA which concurrently serves a mobile AU and a TU in the absence of perfect CSI. Results show that pairing a mobile AU and a TU is more beneficial than pairing TUs only. Furthermore, NOMA provides up to 99% rate of improvement and lower outage probability as compared to OMA. Performance analysis for AUs and TUs in multi-cell networks is also carried out by using stochastic geometry. The analysis highlights the effects of different network parameters and reveals that the network performance can be affected by user association, receiving antenna configuration and ICI mitigation technique. This thesis proposes and provides an important insight about an efficient combination of user association, transmitting and receiving strategies known as aerial-terrestrial network NOMA. The proposed scheme outperforms existing schemes up to 91% in terms of sum-rate and its analytical outage probability can be as low as the order of 10-17. This thesis concludes that NOMA can efficiently serve the AUs and TUs in downlink cellular networks
A new perspective on the relationship between the construction industry performance and the economy outcome-a literature review
No full textThe attempts to analyze the relationship between the construction industry and economic growth have integrated many different methods. The process has become to be perceived as "construction economics" analysis. It is conceptualized as a procedure where construction industries outcomes implement increasingly more relevant for nations development benefits throughout mostly economic interdependencies that are emphasized as financial sources. Concurring with the present-day standards for affirming an industry, in considerably most facets of analysis result interpreted on a solely economic aspect which is not a conspicuous and significant indicator, for construction industry initiates through its resolution outcome. Whereas proceed competently and developed directions from scholars or experts are the determinants of success that emerge due to reviews of relevant practical and research inferences. Literature for analysis on output in the construction industry within the economics aspect is further inscribed in detail. Consequently, relocating the ideology used to examine construction activates implications on development augmentation and shifts the schemes for classifying construction output in the numerous conservative analytic techniques towards more functional delineation. Considering and optimize more relevant details in the systematic process of quantifying the construction value analysis will implicate a reflected actual and detailed results of industrial or enterprise entities on both theoretical and empirical perception for construction economics
Magneto-rheological (MR) damper – parametric modelling and experimental validation for lord RD 8040-1
Full text linkMagneto-rheological (MR) fluid technology has significantly developed during the past decades. The application of MR fluids has proliferated in various engineering fields with the development of MR fluid-based devices, especially MR fluid dampers. MR dampers are semi-active devices used for vibration reduction in many engineering applications. The MR dampers could offer an outstanding capability in semi-active vibration control due to excellent dynamical features such as fast response, low power consumption, and simple interfaces between electronic input and mechanical output. Modelling of MR damper is crucial in describing MR damper’s behaviour. It is critical to comprehend the dynamic behaviour of these devices, as nonlinear hysteresis is a rather complex phenomenon. The Modified Bouc-Wen model represents the MR damper mathematically since this model is capable of performing as precisely as the non-parametric model. The Modified Bouc-Wen model parameters are damper dependent and must be defined for further simulation studies before utilising the damper. Validation of MR damper experimentally is one of the tasks required to confirm the parametric model performance. The specified parameters are believed to be worthwhile for this MR damper’s use in further studies of real-time semi-active (SA) suspension systems. The small values of percentage difference for force (0.5-3.5%) indicate that the parameters implemented in the Modified Bouc-Wen model accurately portray the characteristics and behaviour of the MR damper
Arc flash analysis on kimanis power plant switchgears based on IEEE 1584 standard
Full text linkAn arc flash radiates energy that can seriously burn the skin and clothing and even can lead to death. In most protection systems, the fault clearance times are based on bolted short circuit currents. In the event of an arcing fault, the lower fault current may result in a longer fault clearance time. In some cases, this may result in an increase in the fault energy, which will pose a greater risk to personnel. In many facilities, most of the equipment will have a Category 1 or 2 PPE rating. Equipment that requires Category 3 or 4 would not be able to be identified until an arc flash analysis is completed. Hence in this study, arc flash analysis is done based on the IEEE 1584 Standard by using a short-circuit analysis. Studies of normal and abnormal operations are carried out to simulate maximum and minimum fault conditions. This analysis is performed using ETAP ArcSafety - AC Arc Flash simulation software. With the short-circuit calculation and arc flash analysis done, the correct category rating of arc flash rated PPE according to the NFPA 70E clothing standard were able to be determined and other mitigation measures where necessary were recommended