Taiwan Association of Engineering and Technology Innovation: E-Journals
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Dynamic Power Management Model for a Wireless Sensor Node
Get PDFDynamic power management (DPM) is an efficient technique to design low-power and energy-efficient nodes for wireless sensor networks. This article demonstrates the stochastic behaviour of an input event arrival which is modelled with first-in first-out (FIFO) queue and a single server. An event-driven sensor node is developed based on semi-Markov model. The article investigates the factors affecting the performance of the individual sensor node with detailed analysis considering power consumption and lifetime to be the performance metrics under study. The results demonstrate the impact of the change in event arrival and the probability of change detection on the performance of the node. It is observed that (i) the number of generated events increases with the change in the average value of the distribution which affects the service time in turn resulting in a variation of the server utilization, and that (ii) the increase in the detection probability increases the power consumption decreasing the lifetime of the node
Closed Loop V/f Speed Control of Multilevel Inverter Fed Induction Motors Using PID and Fuzzy Logic Controllers
Get PDFThe Volts per Hertz (V/f) speed control method makes induction motors available to be used in variable speed applications. However, the great harmonic distortion in supply voltage is a major issue of this method. Therefore, this study focuses on decreasing the harmonic distortion in the supply to induction motors. For that, the use of thirty-one-level multilevel inverters (MLIs) is investigated. Another drawback of the V/f speed control method is the use of proportional-integral-derivative (PID) controllers as speed controllers, which are difficult to be tuned precisely. To overcome this, the use of fuzzy logic controllers is investigated. The whole model is developed and simulated in MATLAB/SIMULINK by varying two variables, i.e., reference speed and load torque, one at a time using each controller. The observations for the changes in speed, torque, stator current, and supply voltage to the induction motors are made. The system’s performance using fuzzy logic controllers is found superior
Heat Transfer Augmentation of Concentrated Solar Absorber Using Modified Surface Contour
Get PDFThis work aims to compare the cavity surface contour’s thermal performance to that of the solar absorber’s plain surface contour for Scheffler type parabolic dish collectors. The absorber is tested for the temperature range up to 600°C without working fluid and 180°C with the working fluid. The modified absorber surface's thermal performance is compared with the flat surface absorber with and without heat transfer fluid. The peak temperature reached by the surface modified absorber (534°C) is about 8.6% more than that of the unmodified absorber (492°C) during an outdoor test without fluid. The energy efficiency of cavity surface absorber and plain surface absorber are 67.65% and 61.84%, respectively. The contoured cavity surface produces a more uniform temperature distribution and a higher heat absorption rate than the plain surface. The results are beneficial to the design of high-temperature solar absorbers for concentrated solar collectors
Reduced Path Successive Cancellation List Decoding for Polar Codes
Get PDFPolar codes have already been adopted in 5G systems to improve error performance. Successive cancellation list (SCL) decoding is usually used at the decoder and involves lengthy processing. Therefore, different methods have been developed to reduce an SCL decoder’s complexity. In this paper, a reduced path successive cancellation list (RP-SCL) decoder is presented to reduce this complexity, where some decoding paths are pruned. The pruning is achieved by using three different thresholds: two for the path metric and one for the pruning depth in the decoding tree. An optimization procedure is considered to determine the optimum settings for these thresholds. The simulation tests are carried out over models of an additive white Gaussian noise channel and a fading channel by using 5G environments. The results reveal that the proposed RP-SCL decoder provides the complexity reduction in terms of the average number of processed paths at high SNR. Additionally, the computational complexity and the memory requirements decrease
Using Deep Learning Technology to Realize the Automatic Control Program of Robot Arm Based on Hand Gesture Recognition
Get PDFIn this study, the robot arm control, computer vision, and deep learning technologies are combined to realize an automatic control program. There are three functional modules in this program, i.e., the hand gesture recognition module, the robot arm control module, and the communication module. The hand gesture recognition module records the user’s hand gesture images to recognize the gestures’ features using the YOLOv4 algorithm. The recognition results are transmitted to the robot arm control module by the communication module. Finally, the received hand gesture commands are analyzed and executed by the robot arm control module. With the proposed program, engineers can interact with the robot arm through hand gestures, teach the robot arm to record the trajectory by simple hand movements, and call different scripts to satisfy robot motion requirements in the actual production environment
Finite Element Based Comparative Analysis of Positive Streamers in Multi Dispersed Nanoparticle Based Transformer Oil
Get PDFThe dispersion of dissimilar nanoparticles (NPs) in transformer oil (TO) has a major impact on fast propagating positive streamers. This work investigates the positive streamer dynamics in TO modified by dispersing both Fe3O4 and Al2O3 NPs at a homogenous concentration. The hydrodynamic drift diffusion model of positive streamer evolution and propagation are solved using the commercial software package COMSOL Multiphysics. The impact of multiple NPs (MNPs) has been analysed for streamer propagation, electric field intensity, electron density, and space charge density of modified TO. MNPs successfully reduce streamer propagation velocity by 50%, 17%, and 37.5% comparing to pure oil, Fe3O4 based nanodielectric fluids (NDFs), and Al2O3 based NDFs, respectively. The spatial distribution of electron density reveals the loss of electrons from the ionization region until the saturation of NPs. A comparative study demonstrates that MNPs significantly alter the streamer dynamics and augment the dielectric strength of TO compared to individual NPs
Security Enhancement in Image Watermarking Using Combined Medium Sub-Band Wavelet Approach for Copyright Protection
Get PDFWatermarking in multimedia content has secured attractive approaches in research society since nowadays the transmission of digital content in wireless medium has been enormous. Along with the distribution of digital content, it is important to claim ownership. A non-blind detection technique is proposed in this paper. First, an original image undergoes the wavelet decomposition such as LL1, LH1, HL1, and HH2. Afterward, the medium level sub-band coefficients of the image are subject to the comfortable shares for merging. Next, one of the shares from the LH1 band is merging with another one of the shares in HL1 band. In this stage, the copyright mark is fetched into the merged sub-band coefficients. Finally, an inverse wavelet transform is applied to receive the watermarked image. To prove the authentication, the original image and the watermarked image undergo the same operation and acquire copyright information. Experimental results achieve that the proposed approach can withstand various image processing attacks
Application of Image Processing Techniques for Autonomous Cars
Get PDFThis paper aims to implement different image processing techniques that will help to control an autonomous car. A multistage pre-processing technique is used to detect the lanes, street signs, and obstacles accurately. The images captured from the autonomous car are processed by the proposed system which is used to control the autonomous vehicle. Canny edge detection was applied to the captured image for detecting the edges, Also, Hough transform was used to detect and mark the lanes immediately to the left and right of the car. This work attempts to highlight the importance of autonomous cars which drastically increase road safety and improve the efficiency of driving compared to human drivers. The performance of the proposed system is observed by the implementation of the autonomous car that is able to detect and classify the stop signs and other vehicles
Numerical Study of Geosynthetic-Reinforced Soil Wall Subjected to Static Footing Loading
Get PDFThis study intends to examine the behavior of a GRS wall with static footing loading above it, while varying the positions of the footing. For the study of behavior of such complex structure, finite element modeling is handy and enables to look into the various stress/strain developed in the numerical model. In view of the above, a series of finite element (FEM) simulations using a software (Optum G2) is performed for the analysis of the GRS wall. The governing parameters, such as footing width (B), reinforcement length (L), offset distance (D), are evaluated and the effect of these factors on the ultimate bearing capacity (q) and settlement (s) of the footing is presented in this study. The results depict that the settlement of the footing substantially reduced in the range of 36% and its ultimate bearing capacity is increased to 42% more than the conventional retaining walls
Optimization of Multi-Band Characteristics in Fan-Stub Shaped Patch Antenna for LTE (CBRS) and WLAN Bands
Get PDFThis study aims to optimize a fan-stub slot patch to get better suitability and performance for Citizens Broadband Radio Service (CBRS). The transition from the tedious configuration of slotted patch antenna in fan-stub shape is evaluated. Also, the impact of stub width W, stub length L, and its orientation are tested. Multiple simulation tests ensure the uniqueness in the type of slots or stubs that affect the multiband nature of patch. The optimization of basic fan-stub structure on return loss S11, Voltage Standing Wave Ratio (VSWR), and the operating band at the desired frequency is performed to accommodate the federal and non-federal use of the band. The simulation results show that the designed antenna is technically suitable to cover 4G LTE in CBRS (LTE-43 and LTE-48 band) as well as 5.5 GHz Wireless Local Area Network (WLAN) band of operation