Universiti Putra Malaysia
Download Latest Complete Journal - JST Vol. 25 (S) Jan. 2017
No.ArticlesDownloads
1
Full Article
(Downloads: 28)
Abstract (Viewed: 5)Musculoskeletal disorders (MSDs) caused by muscle fatigue have been a major problem for industry which needs to be resolved to save costs related to human resource development (extra training and compensation). Detailed fatigue monitoring researches aimed at finding the best fatigue indices is not new although studies on the causes of fatigue can be explored further. Identification analysis is required to monitor the factors that influence muscle performance characteristic of surface electromyography (sEMG) signal. Periodogram monitoring technique applies a frequency domain signal and represents the distribution of the signal power over the frequency. It is a technique that allows the tracing of small changes in the behaviour of sEMG signal when external parameters are varied. This technique is used in this paper to monitor the sEMG signal changes in muscle performance when the lifting height and load mass are varied. The periodogram amplitude, which represents the power, increases with the rise in lifting height and load mass. From the frequency representation of the periodogram, the root mean square voltage (Vrms) is calculated where the muscle performance characteristic could be further identified. The Vrms also shows a similar trend when the lifting height and load mass are varied proving the periodogram technique is useful to monitor changes in the muscle performance during manual lifting. Periodogram, electromyography, frequency representation, manual lifting
2
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(Downloads: 16)
Abstract (Viewed: 1)This paper proposes a half-bridge LLC resonant converter with two resonant tanks for plug-in electric vehicle (PEV) battery charging. Each resonant tank is connected with one of the centre-tapped primary windings of the power transformer. Both resonant tanks are fed alternately by a half cycle of the switching pulse in one period. The converter is designed to operate below resonance zero-voltage switching (ZVS) region to reduce switching losses and to achieve output DC voltage range 250V-420V with 400V input DC voltage for depleted PEV battery. MATLAB Simulink is used to simulate the circuit with 1.5 kW maximum power and the simulation results show that the converter can meet the constant-current, constant-voltage (CC-CV) charging requirements of the depleted PEV battery. LLC resonant converter, PEV battery charger, FHA
3
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(Downloads: 21)
Abstract (Viewed: 4)This paper reports the experimental results of the partial surfaces ion balance analysis on ionised planar surface to identify the fine-grained level of ioniser balance measurement. The standard 6"×6" charged plate was exposed to ionised air supplied through the DC corona ioniser to measure the ion balance. A one square inch charged plate had been used to measure the ion balance in the 36-segment partial measurement points which were ordinary arranged on that planar surface. The 36-segment partial results were analysed to image the ion balance distribution on that planar surface. The experiment revealed that fined-grained levels could be identified behind the coarsely results which had been measured by the standard charged plate. The surface plot could image the ion balance distribution on that planar surface which was ionised by the ioniser thoroughly. This ion balance imaging could be used to enhance ioniser performance analysis related to ion balance and distribution along the ionised surface. Ion balance, ioniser measurement, partial surface, ion balance distribution
4
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(Downloads: 16)
Abstract (Viewed: 3)Phasor Measurement Units (PMUs) are an important component in Wide Area Protection (WAP)- based operations in power systems. It is needed that a certain placement scheme of PMUs is suggested if power system scale gets larger. The optimal placement of PMU in power systems has been considered and formulated in order to reduce the number of installed PMUs while accomplishing a desired level of reliability of observation. Optimal PMU Placement (OPP) problem as the combinatorial optimization problem has been formulated to determine the minimum PMU location in the power system. In this paper, Disparity Evolution-type Genetic Algorithm (DEGA) based on disparity theory of evolution is applied. Genetic Algorithm (GA) is employed for the purpose of comparison with DEGA. The optimization model is solved for IEEE 118 standard bus system. DEGA can find better placement suggestion compared with GA because of the nature of evolution that models the double spiral structure of DNA to hold the diversity of population.Observability, Phasor Measurements, Genetic Algorithm, optimization
5
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(Downloads: 17)
Abstract (Viewed: 3)In this study, nitrogen doped titanium dioxide-based dye-sensitised solar cell was successfully fabricated using screen printing technique to discover the optimisation of process parameters for the solar cell efficiency using response surface methodology (RSM). Parameter optimisation has been a major concern in solar cell fabrication. The selected parameters were: nitrogen concentration (15-25 mg of urea), the film thickness (25-60 µm) and dye loading time (12-24 hours), the optimum condition which yields the highest efficiency of 3.5% was at 15 mg nitrogen concentration, 25 µm film thickness and 24-hours dye loading time. Film thickness was found to have a significant influence on efficiency while the loading time exceeding 18 hours has the least significant effect. Dye-sensitised, solar cell, nitrogen, screen printing, optimisation
6
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(Downloads: 18)
Abstract (Viewed: 2)Herbs have unique characteristics such as colour, texture and odour. In general, herb identification is through organoleptic methods and is heavily dependent on botanists. It is becoming more difficult to identify different herb species in the same family based only on their aroma. It is because of their similar physical appearance and smell. Artificial technology, unlike humans, is thought to have the capacity to identify different species with precision. An instrument used to identify aroma is the electronic nose. It is used in many sector including agriculture. The electronic nose in this project was to identify the odour of 12 species such as lauraceae, myrtaceae and zingiberaceae families. The output captured by the electronic nose gas sensors were classified using two types of artificial intelligent techniques: Artificial Neural Network (ANN) and Adaptive Neuro-Fuzzy Inference System (ANFIS). From the result, ANFIS has 94.8% accuracy compared with ANN at 91.7%. Artificial Neural Network, Adaptive Neuro-Fuzzy Inference System
7
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(Downloads: 13)
Abstract (Viewed: 5)Special Protection Schemes (SPSs), are corrective action schemes that are designed to protect power systems against severe contingency conditions. In planning of SPSs, protecting transmission network from overloading issue due to critical situations has become a serious challenge which needs to be taken into account. In this paper, a Special Protection and Control Scheme (SPCS) based on Differential Evolution (DE) algorithm for optimal generation rescheduling has been applied to mitigate the transmission line overloading in system contingency conditions. The N-1 contingency has been performed for different single line outages under base and increased load in which generation rescheduling strategy has been undertaken to overcome the overloading problem. Simulation results are presented for both pre-and post system emergency situations. The IEEE 30-bus test system was utilised in order to validate the effectiveness of the proposed method. Special Protection Scheme, transmission line overloading, line contingency, generation rescheduling, Differential Evolution (DE) algorithm
8
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(Downloads: 14)
Abstract (Viewed: 1)The purpose of this study was to identify a method to form rubber composites by incorporating natural rubber (NR) and wood ash from rubber trees with a preliminary electrical properties test. This formulation is intended to improve the rubber composites in order to obtain new materials for high voltage insulators. First, the rubber formulation and processing conditions were optimised before the composites are processed in the laboratory. Second, the interactions between the NR and wood ash were investigated with the following tests: cure time, agglomerate dispersion, SEM images, and the electrical characteristic test. In the electrical characteristic test, the experimental setup was designed for testing the frequency range from 50 Hz to 100 kHz, which is the range of high voltage power line switching frequencies. This energised transient frequency can occur due to switching operations or any other external causes in high voltage systems. Finally, the dielectric property of the rubber composites was evaluated and the equivalent circuit was formulated. The results show that the different properties tested with the new material not only correspond with the filler contents, but also with the frequencies in the transmission lines. The measured data are extracted and converted into other parameters at each frequency. The comparison results are closely matched. Moreover, the results revealed that relative permittivity and the conductivity increases the wood ash filler is increased.Rubber composites, high voltage insulator, rubber formulation, electrical characteristic test
9
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(Downloads: 11)
Abstract (Viewed: 1)Self-sensing actuation (SSA) is a technique to use a single piezoelectric actuator as both an actuator and a sensor simultaneously. A self-sensing actuation circuit is used to extract a voltage generated by a piezoelectric actuator from a control voltage. However, the SSA circuit must be balanced to obtain an accurate sensing voltage. This paper describes an effect of an unbalanced SSA circuit on the sensing voltage output. The SSA circuit is connected to a piezoelectric system to apply the control voltage and measure the generated voltage simultaneously. The unbalanced SSA circuit is configured by designing an equivalent capacitance parameter to be not equal to a piezoelectric capacitance. The unbalanced SSA circuit effects is evaluated in terms of the step response and the frequency response. An experiment is conducted in an open-loop system and a closed-loop system. In the open-loop system, the sensing voltage is observed when the control voltage is applied to the piezoelectric actuator. In the closed-loop control system, a positive position feedback (PPF) controller is used for vibration control at a resonant frequency of the piezoelectric system. Experimental results show that the unbalanced SSA circuit causes the sensing voltage error when the amplitude of the control voltage is larger than the amplitude of the voltage generated from the piezoelectric actuator. In this case study, the unbalanced SSA circuit does not affect the vibration control at the resonant frequency in the closed-loop system. The vibration of the piezoelectric system at the resonant frequency is attenuated by 16 dB in both the balanced and the unbalanced SSA circuit conditions. Self-sensing actuation circuit, unbalanced SSA circuit, piezoelectric actuator, vibration control
10
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(Downloads: 11)
Abstract (Viewed: 1)This paper presents a tracking method based on parameters between colour blobs. The colour blobs are obtained from segmenting the overall target into multiple colour regions. The colour regions are segmented using EM method that determines the normal colour distributions from the overall colour pixel distribution. After segmenting into different regions on the different colour layers, parameters can be generated between colour regions of interest. In this instance, the colour regions of interest are the top and bottom colour regions. The parameters that are generated from these colour regions are the vector magnitude, vector angle and the value difference between colour regions. These parameters are used as a means for tracking targets of interest. These parameters are used for tracking the target of interest across an array of cameras which in this instance are three cameras. Three cameras have been set up with different background and foreground conditions. The summarised results of tracking targets across three cameras have shown that the consistency of colour regions across different cameras and different background settings provided sufficient parameters for targets to be tracked consistently. Example of tracking performance across three cameras were 0.88, 0.67 and 0.55. The remaining tracking performances across three cameras are shown in Table 2. The tracking performance indicate that the parameters between colour regions were able to be used for tracking a target across different cameras with different background scenarios. Based on results obtained, parameters between segmented colour regions have indicated robustness in tracking target of interest across three cameras.Blob tracking, parametric tracking, multiple camera, tracking
11
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(Downloads: 12)
Abstract (Viewed: 2)An electric power system generate electricity to meet demands. Distributed Generation (DG) allows electricity to be generated in a small capacity where the customer is located. In this paper, multi-objective functions based on the indices of system performance are formulated and used to determine the best location. The Differential Evolution technique (DE) has been employed to calculate optimal sizing for each location. Unity power factor DG model have been studied in this work and the problems solved with one DG unit. IEEE 14 bus has been used as a test system. Distributed Generation (DG), Differential Evolution (DE), multi-objective function (MOF)
12
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(Downloads: 11)
Abstract (Viewed: 1)In this paper, a configuration of a single-stage AC-DC converter and a high voltage resonant controller IC L6598 for LED street light driver is discussed. The converter is obtained by integrating two boost circuits and a half-bridge LLC resonant circuit. A voltage double rectifier circuit is adopted as output to lower the voltage stress on transformer and the associated core. The two boost circuits work in boundary conduction mode (BCM) to achieve the power factor correction (PFC). The converter works in soft-switching mode allowing the power switches to operate in zero-voltage-switching (ZVS) and the output diodes to operate in zero-current-switching (ZCS). This reduces the switching losses and enhances the efficiency. The converter features lower voltage stress on the power switches and the bus voltage is reduced to slightly higher than the peak input voltage. Therefore, the converter can perform well under high-input-voltage. Here, the DC bus and the output filter capacitances are greatly reduced. So, electrolytic capacitor-less converter can be realized for a long lifetime LED driver. Simulation results from PSpice are presented for a 100-W prototype. LED driver, boost circuit, LLC, power factor correction, street lighting, voltage doubler
13
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(Downloads: 13)
Abstract (Viewed: 1)Hydrogen fuel cell (HFC) is one of the renewable resources to address fossil fuel depletion and global warming. Its primary advantages are power is generated from renewable fuel hydrogen and the emission is only water. However, HFC supplies power in a slow dynamic response. In fuel cell electrical vehicle (FCEV), energy storage system (ESS), i.e. supercapacitor and battery, is required to immediately compensate the difference between load demand and power supply; the lifetime of HFC is affected by current ripple. In order to manage power flow between HFC and load, HFC is interfaced with a unidirectional DC-DC converter. The converter steps up the terminal fuel cell voltage and regulate the voltage before it is connected to the load. Among the proposed HFC DC-DC converters, interleaved DC-DC converter seems more suitable for FCEV application due to its advantages. When galvanic isolation is required, current fed full bridge converter receives significant consideration as the module of interleaved converter. This paper simulates interleaved current fed full bridge (ICFFB) converter and discusses the suitability of ICFFB for FCEV application. Hydrogen fuel cell, DC-DC converter, electric vehicle
14
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(Downloads: 9)
Abstract (Viewed: 1)This paper proposes a novel double series resonant dc-dc converter with uniform voltage stress on a transformer. It consists of a half-bridge inverter with two power switches (IGBTs), two series resonant tank, two high-voltage transformers and a symmetrical voltage multiplier circuit. A symmetrical voltage multiplier circuit is connected at the secondary side of the high voltage transformer to generate desired high voltage dc output. Due to use of voltage multiplier circuit, the proposed converter requires smaller turns ratio of the high voltage transformer, leading to reduction in size and volume of the transformer. The proposed converter operates in discontinuous current mode by varying the switching frequency of the converter. In a discontinuous current mode operation, all the power switches and output diodes of the rectifier circuit turn-on and turn-off under zero current switching conditions. Therefore, it has features of low switching losses and possibility of light-load operation. Besides, it costs less and is smaller in size compared with conventional double series resonant dc-dc converter. It also has a simple operating principle and suitable for high voltage and high power applications. Experimental results confirm the proposed converter performs better than the others. Series resonant converter, zero current switching, high voltage, dc-dc converter
15
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(Downloads: 10)
Abstract (Viewed: 1)Nowadays, induction motors are widely used for many industrial processes. The shorted-turn fault of the stator-winding is the initial point of stator winding faults. This paper proposes using the Principal Component Analysis (PCA) to reduce the dimension of the feature set which is obtained from the Motor Current Signature Analysis (MCSA). The six original features consist of the signal power of the three-phase filtered current signal at 20 Hz to 80 Hz and 120 Hz to 180 Hz of the phases A, B and C. After using the PCA, the dimension of the feature set decreases to two new features. These two new features are then used to classify the shorted-turn phases of the stator-winding by applying the Artificial Neural Network (ANN) classifier. The experimental results demonstrate that the new feature set can decrease the complexity of the system. Additionally, the accuracy rate using the new feature set is higher than using the original feature set. Therefore, the new feature set can properly improve the efficiency of the classification.Induction motor, interturn short circuit fault, shorted-turn fault, stator-winding fault, Principal Component Analysis (PCA), Artificial Neural Network (ANN)
16
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(Downloads: 10)
Abstract (Viewed: 1)Graphene band structure can be modulated when dopant atoms are introduced into graphene sheets. As a result, there is flexibility in design and optimisation of electronic devices. In this study, the effects of atomic doping to graphene band structure were investigated by using boron and oxygen as dopant atoms. Different dopant concentrations and dopant locations in graphene sub lattices were studied by using a 4x4 graphene sub lattice which consists of 32 carbon atoms. Results show that both dopants cause opening of energy band gap of mono layer graphene. The highest energy band gap (Eg) value for graphene doped with boron is 0.52 eV and the highest Eg value for graphene doped with oxygen is 1.67 eV, in which both results are obtained for highest dopant concentration and farthest dopant's distance in a graphene sheet. This shows that higher dopant concentration and farther dopant's location in a graphene sheet lead to higher energy band gap.Graphene, band structure, band gap, boron, oxygen, atomic doping
17
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(Downloads: 8)
Abstract (Viewed: 2)Researchers have observed the impact of climate changes on overhead line outages. It is known that overhead lines are very prone to lightning strikes due to their height and location which are normally in an open and exposed area. Studies have also reported that transmission and distribution lines experience very high failure rates due to lightning strikes. The tropics experience greater lightning activities and have higher peaks where transmission lines suffer frequent line outages. This paper examined studies that have been conducted on line outages due to lightning activities, especially in the tropical areas. Lightning detection system is also discussed as well as how to evaluate line performance. Seasonal variation of lightning occurrences and line outage pattern help to predict lightning occurrences and to optimise a suitable power protection system of overhead lines. It has been widely reported that lightning occurrences and line outages are significantly related and lightning activity was more prevalent during inter monsoon seasons.Transmission lines, lightning performance, lightning, tropical weather
18
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(Downloads: 9)
Abstract (Viewed: 1)The radiation absorption distribution of electromagnetic energy into the breast phantom is of fundamental importance in understanding its therapeutic capability emitted by the microstrip applicator for non-invasive hyperthermia procedure. In this paper simple microstrip applicator with rectangular shape is presented. Different operating frequency were investigated to observe radiation absorption distribution, which is measured through specific absorption rate (SAR) parameter. The operational frequency was 915 MHz and 2450 MHz, the industry, scientific and medical (ISM) frequency range. As simulated by using the finite difference time-domain (FDTD) computational simulation which is known as SEMCAD X solver, the results shed an interesting observation on the SAR when frequency varies, which is shown by the transformation onto the penetration depth and focusing capability onto the breast area to be treated.Non-invasive, hyperthermia, SAR, microstrip applicator
19
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(Downloads: 11)
Abstract (Viewed: 1)Flexible AC Transmission System (FACTS) devices are used in to improve stability and loadability of transmission networks as well as minimise losses. Types of FACTS that are normally used are Thyristor Controller Series Compensator (TCSC) and Unified Power Flow Controller (UPFC) which is to control power flow and stability of the power system at a certain location. The TCSC is suitable because it can be installed in a long transmission line system while UPFC can solve any reactive power problems. The objective of this study is to minimise total power losses and to improve the voltage profile by using FACTS devices in the transmission system. This paper proposes a static voltage stability index (SVSI) to determine the size and placement of TCSC and the Evolutionary Programming (EP) technique. The results of the transmission line losses and voltage profile using TCSC and UPFC are compared in order to demonstrate which FACTS device can produce better results. The IEEE 14 bus system is used in this study to validate the findings.Evolutionary Programming (EP), Thyristor Controlled Series Compensator (TCSC), Unified Power Flow Controller (UPFC), Flexible AC Transmission System (FACTS), Static Voltage Stability Index (SVSI)
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(Downloads: 11)
Abstract (Viewed: 1)Power systems are usually exposed to numerous disturbances that can have an adverse effect on system operation. Insufficient generation could lead to frequency declination and subsequently system collapse in the absence of immediate control action. Frequency Load Shedding (UFLS) is a technique commonly applied to overcome overloading and restore the system frequency. This paper presents an adaptive load shedding approach to determine the best location with minimum amount of load to be shed. Load Ranking Fuzzy Logic (LRFL) is used to rank the load based on their sensitivity and stability index. In order to achieve this, the proposed strategy is verified using 11 kV Malaysian distributed network consisting of different type of loads connected with single and multiple Distribution Generator (DG). The simulation results show that the proposed strategy successfully stabilizes the system's frequency.Distribution Generator, Under Frequency Load Shedding, Load Ranking based Fuzzy Logic, Load Priority
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(Downloads: 12)
Abstract (Viewed: 2)This research presents compensation of current harmonic disturbance in power system network using shunt active power filter. In this paper, harmonic extraction using Synchronous Reference Frame Fundamental technique (SRFF) was investigated for three phase 3-wire system. It proposes a method based on direct current measurement of load currents using a band pass filter at low cut off frequencies to improve the filtering ability in highly contaminated loads. The proposed filter consists of second order low pass and high pass filters cascaded together at suitable frequencies, estimated based on the output of these units to mitigate the current harmonics. The performance of the system was simulated in Matlab Platform and evaluated considering total harmonic distortion of the source current in a three-phase balanced network. The simulation results show the ability of the proposed tracking scheme to accurately estimate harmonics. Shunt active power filter (SAPF), power quality, harmonics, synchronous reference frame (SRF), Low pass filter, high pass filter, band pass filter
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(Downloads: 10)
Abstract (Viewed: 1)Negative bias temperature instability (NBTI) is a common phenomenon in a p-channel MOSFET device under a negative gate-to-source voltage at a high stress temperature. This paper presents the NBTI characterisation based on different analysis methods and stress conditions on p-MOSFET devices. The atomic hydrogen concentration is probed at interface, Poly-Si and channel of p-MOSFET under study using SILVACO TCAD tool. In addition, the behaviour of the permanent and recoverable component was investigated based on AC stress at different stress conditions using Modelling Interface Generation (MIG) tool. The results show that increases in temperature, negative voltage stress gate and decreases in frequency increase the threshold voltage shift, thus enhancing NBTI degradation.NBTI, temperature, voltage stress gate, frequency, threshold voltage (Vth), AC, DC, recovery
23
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(Downloads: 9)
Abstract (Viewed: 1)This paper presents a methodology to determine the economic power factor at the point of power transfer between transmission and distribution (T & D) system for a vertically integrated utility company. An integrated reactive power management strategy is developed to optimize the planting up of reactive power compensation devices in the transmission and distribution system. The transmission and distribution network is modelled and simulated using commercially available software to analyse the transmission network losses, capacity released and voltage stability due to capacitor plant up. Economic analysis on the total cost of ownership of capacitor banks is used to determine the economic benefits of technical losses reduction and capacity released in transmission and distribution equipment through the planting up of capacitor bank. The proposed methodology can be used by a vertically integrated power utility where a single utility own both the transmission and distribution system. A software base data analytic, power system automation and economic analysis tool was developed to facilitate the planning engineer in reactive power planning and management. Reactive power management
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(Downloads: 11)
Abstract (Viewed: 1)Planar electromagnetic sensors are widely used in many applications due to its low cost, simple architecture, and fast response. Currently, there are many types of membranes which have been introduced to remove contaminants from an aqueous solution. Hence, the water quality could be maintained and safe to consume. The objective of this paper is to apply and investigate the effectiveness of a selective membrane in detecting nitrate, phosphate, zinc, and nickel ions by means of planar electromagnetic sensors array (PESA). The samples have four different concentration levels, 5 ppm, 25 ppm, 75 ppm, and 100 ppm. The selective membrane's performance is evaluated based on absolute average sensitivity (|Z%|). This performance is compared with conventional coating such as incralac. The developed membrane consists of two elements which are polymer and solvent. Modified silica is selected as a polymer material while N-(2-Aminoethyl)-3 Aminipropyltrimethoxysilane is selected as a solvent. The selection of these materials is based on their ability to attract the contaminants in the aqueous solution and hence increased the selectivity. The proposed sensor with a membrane shows its higher sensitivity compared to incralac. The highest sensitivity is 338 % which observed in the presence of membrane for the nickel detection. Meanwhile, the lowest sensitivity using membrane is 12 % for zinc detection.Planar electromagnetic sensor array, water contaminants, star configuration, water supply quality
25
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(Downloads: 13)
Abstract (Viewed: 2)Radio telescope is an application that requires a precise position control as it should point to the exact coordinate so that it could receive the desired signal. The main idea of this paper is to optimise the PID controller by introducing slope variation method in order to control the position of a radio telescope. This proposed method is also validated with the presence of disturbance, such as wind gust disturbance with different speed amplitude. The results indicate that the proposed optimisation method has a better result with no overshoot and able to attenuate wind gust disturbance when compared with conventional PID controller.PID optimisation, position control, radio telescope
26
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(Downloads: 18)
Abstract (Viewed: 10)Malaysia has introduced a new Time of Use (ToU) tariff scheme known as Enhanced ToU (EToU) for commercial and industrial customers. EToU is a more detailed pricing scheme where one day time frame is divided into six period blocks as compared to only two period blocks in the existing ToU. Mid-peak tariff is introduced to the existing peak and off-peak tariff. Off-peak rate for EToU is significantly lower than the existing off-peak rate but the peak rate is much higher. EToU is designed to motivate users to reduce their consumption during peak hours or shift the load to mid-peak or off-peak hours, which if done correctly can reduce the electricity bill while maintaining electricity consumption. This new EToU scheme will benefit consumers if they are able to shift consumption from peak-hours into mid-peak or off-peak hours. This paper assesses the amount of load shifting that is required based on customers' load profile and EToU rates. The load profile data of an office building in Putrajaya, Malaysia is used as a case study. Time-of-Use, load profile, electricity consumption
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(Downloads: 9)
Abstract (Viewed: 1)Negative bias temperature instability (NBTI) is the most concern issue CMOS devices with the scaling down of the CMOS technologies. NBTI effect contributes to P-MOSFET device degradation which later reduce the performance and reliability of CMOS circuits. This paper presents a reliability simulation study based on R-D model on CMOS inverter circuit. HSPICE MOSRA model together with the Predictive Technology Model (PTM) was used as to incorporate the NBTI model in the circuit reliability simulation study for different technology nodes. PTM of High Performance (HP) models of 16nm, 22nm, 32nm and 45nm were used in this simulation study. The atomic hydrogen based model was integrated in the simulation. The results show that in a CMOS inverter circuit, the threshold voltage shift of p-MOSFET under NBTI stressing increased as the year progressed. The threshold voltage shift was observed to increase up to 45.1% after 10 years of operation. The time exponent, n ~ 0.232 of the threshold voltage shift observed indicates that the defect mechanism contributed to the degradation is atomic hydrogen. The propagation delay increased to 19.5% over a 10-year period up to 19.5% from the zero year of operation until 10 years of the operation. In addition, the time propagation delay increased as year increased when the technology nodes smaller. The finding is important for understanding reliability issues related to advanced technology nodes in CMOS circuits study.NBTI, CMOS Inverter, Predictive Technology Model, HSPICE MOSRA, circuit reliability
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(Downloads: 11)
Abstract (Viewed: 1)Having cooperation between multiple autonomous devices against one task is difficult due to each device having their own decision management based on self-deterministic protocol. Within the self-deterministic protocol, a formation management task should be considered along another task in order to provide cooperation and consideration between the operating autonomous devices. In this research, a compound learning control system for formation management of multiple control agents is proposed by managing coordination between multiple autonomous agents along with other tasks simultaneously in an operation. A series of simulation based on an autonomous robot was conducted to evaluate the effectiveness of learning through compound knowledge for providing consideration among achieving goals or coordination configuration against partner robot. The proposed system was able to provide consideration in coordination among operating partners in a task of achieving goal.Learning control, multi-agent, formation management, reinforcement learning, intelligent control
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(Downloads: 10)
Abstract (Viewed: 1)The purpose of this paper is to classify between healthy and sick chicken based on their dropping. Most chicken farm management system in Malaysia is highly dependent on human surveillance method. This method, however, does not focus on early disease detection hence, unable to and alert chicken farmers to take necessary action. Therefore, the need to improve the biosecurity of chicken poultry production is essential to prevent infectious disease such as avian influenza. The classification of sick and healthy chicken based solely on chicken's excrement using the support vector machine is proposed. First, the texture is examined using grey-level co-occurrence matrix (GLCM) approach. A GLCM based texture feature set is derived and used as input for the SVM classifier. Comparison are made using more and then less extracted features, less extracted features and also applying Gabor filter to these features to see the effect it has on classification accuracy. Results show that having more features extracted using GLCM techniques allows for greater classification accuracy.Support vector machine, feature extraction, GLCM, Gabor filter
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(Downloads: 14)
Abstract (Viewed: 2)Cascaded multilevel inverters are popular in fields such as oil and gas, power supply installations, and power quality devices. While there are many advantages of the cascaded multilevel inverter, its main disadvantage is the need for large numbers of multiple dc sources. In order to reduce total harmonics distortion (THD) of the output voltage waveform, the amount of output voltage level must be increased, hence the higher number of dc sources. This essentially complicated the inverter design, as most converter transform only one voltage source to another. In this paper a cascaded multilevel inverter topology with a single dc source is discussed. The topology is based on capacitors instead of cells as the multiple voltage sources. The cascaded multilevel inverter topology validity and functionality is verified by the Matlab Simulink simulation of a 100W and 1kW aircraft single phase 41-level inverter.Aircraft inverter, multilevel inverter, total harmonics distortion
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(Downloads: 11)
Abstract (Viewed: 2)The use of electroosmotic is fast becoming a proven technique for manipulating particles in microfluidic systems. Several approaches were experimented to improve the force and thus the moving particles in the fluid. This paper will study the effect of microelectrode on the moving particles in latex using a particle image velocimetry and to test the velocity of particles movement at various frequencies from 10 kHz to 500 kHz. The result shows the behaviour of latex particles at different frequencies varying from low frequencies up to high frequencies under AC electrokinetic forces such as dielectrophoresis (DEP) and AC electroosmosis (ACEO). Electrical field, microfluidic, dielectrophoresis, electroosmotic flow, particle image velocimetry, charge density, Clausius-Mossotti factor
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(Downloads: 15)
Abstract (Viewed: 6)This work proposes an output feedback controller for stabilization of the quadrotor underactuated system in the presence of time varying disturbances and model uncertainties. The proposed control is an improvement to the sliding mode control (SMC). An extended high-gain observer (EHGO) when combined with sliding mode control (SMC) able to give feasible performance beyond the performance of the standard sliding mode. It is able to bring the state trajectories of the closed-loop system close to the target system with a smaller ultimate bound of error and smaller control magnitude. The proposed method is illustrated by simulation.Extended high-gain observer, sliding mode control, underactuated system, output feedback control
33
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(Downloads: 14)
Abstract (Viewed: 2)The unified protocols are unified in application interface, models, and seamless. They generate one standard protocol, one world called IEC 61850. IEC 61850 integrate the security, interoperability, modelling, mapping to a substation, and reliability. Presently, the more expensive fiber based Ethernet LAN is the most prevalent technology for medium and low voltage distribution substations. To circumvent this problem Wireless Local Area Network (WLAN) has been investigated for its suitability for applications that are compliant to IEC 61850: automation and metering; control and monitoring; and over-current protection. In this paper the IEEE 802.11n WLAN is studied when used in various IEC 61850 supported applications for substation automation. It also discusses the benefits of using GOOSE message to protect and control applications and the use of IEC 61850. IEC 61850, GOOSE, WLAN, Smart Grid
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(Downloads: 13)
Abstract (Viewed: 2)DNA microarray images contain spots that represent the gene expression of normal and cancer samples. As there are numerous spots on DNA microarray images, image processing can help in enhancing an image and assisting analysis. The mathematical morphology is proposed to enhance the microarray image and analyse noise removal on the image. This follows an experiment in which the erosion, dilation, opening, closing, white top-hat (WTH) and black top-hat (BTH) operations were applied on a DNA microarray image and its results analysed. Noise was completely removed by the erosion operation and the images were enhanced. DNA microarray image, mathematical morphology, image enhancement
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Abstract (Viewed: 2)One of the biggest power consuming devices in wireless communications system is the Power Amplifier (PA) which amplifies signals non-linearly when operating in real-world systems. The negative effects of PA non-linearity are energy inefficiency, amplitude and phase distortion. The increases in transmission speed in present day communication technology introduces Memory Effects, where signal spreading happens at the PA output, thus causing overhead in signal processing at the receiver side. PA Linearization is therefore required to counter the non-linearity and Memory Effects. Digital Pre-distortion (DPD) is one of the outstanding PA Linearization methods in terms of its strengths in implementation simplicity, bandwidth, efficiency, flexibility and cost. DPD pre-distorts the input signal, using an inversed model function of the PA. Modelling of the PA is therefore vital in DPD, where the Memory Polynomial Method (MP) is used to model the PA with memory effects. In this paper, the MP method is improved in Memory Polynomial using Binomial Reduction method (MPB-imag-2k). The method is simulated using a modelled ZVE-8G Power Amplifier and sampled 4G (LTE) signals. It was found MPB-imag-2k is capable of achieving comparable anti-scattering/anti-distortion in MP for non-linearity order of 3, memory depth of 3 and pre-amplifier gain of 2. Power Amplifier, PA Linearization, Digital Pre-Distortion, 4G, Memory Polynomial
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Abstract (Viewed: 2)Normalisation is a process of removing systematic variation that affects measured gene expression levels in microarray experiment. The purpose is to get a more accurate DNA microarray result by deleting the systematic errors that may have occurred when making the DNA microarray slid. In this paper, four normalisation methods of Global, Lowess, Quantile and Print-tip are discussed, tested and their final results compared in the form of Matrixes and graphs. Ideal and real microarray slides have been used for this project. It was found that the Print-tip normalisation method showed the closest results to the real result for an ideal microarray slide and it has a straight median line final graph. The Print-tip normalisation method uses more than one normalization factor that is divided among intervals which are dependent on the values of the addition of red and green logarithm. DNA, Microarray, Normalisation, Global, Lowess, Quantile, Print-tip, Background correction, M-A plot
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Abstract (Viewed: 2)Biologically inspired robotic hands have important applications in industry and biomedical robotics. The grasping capacity of robotic hands is crucial for a robotic system. This paper presents an experimental study on the finger force and movements of a human hand during the grasping operation in real-time. It focuses on two topics; measuring grasping force using Flexi-force sensors and analysing human hand action during grasping operation. The findings show that lifting required higher forces compared with grasp force in the static phase. Hand grasping, Flexi-force sensors, motion capture systems
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Abstract (Viewed: 1)This research attempts to enhance of the ability of Fuzzy Logic Controller in controlling wastewater treatment system, highlighting the pH parameter in factory wastewater treatment plants. The research not only covers methods to monitor and track the pH level in wastewater tank but more importantly, the control of total wastewater volume by neutralising the pH. Fuzzy logic control has gained more attention in the control of continuous processes. It utilised both, in the context of deciding and tracking set-points, and to control the total unwanted water capacity. This paper also discusses suitable level of pH required which will not damage the water ecosystem. The self-learning fuzzy logic control with adaptive capabilities alert operator in charge of the pH level automatically. This research includes the design and development a graphical user interface (GUI) to show the process of pH neutralisation in wastewater treatment. A fast response system is achieved through GUI which could be monitored and control remotely using laptop or smartphone, from anywhere. This proposed design will inform engineers and technicians about the status of the current reading of parameters in the wastewater treatment system without the hassle of going to the site or control room of the wastewater treatment plant. Fuzzy Logic Controller, pH, MATLAB, LabVIEW

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