Taiwan Association of Engineering and Technology Innovation: E-Journals
Not a member yet
887 research outputs found
Sort by
Manufacture and Design an Apparatus for Measuring the Thermal Resistance of Building Materials
Get PDFA good thermal design of buildings plays a key role in reducing the thermal loads of heating and air conditioning systems and thus reducing energy consumption. This study develops a steady-state apparatus for measuring the thermal resistance of building materials by using an absolute technique. The apparatus is designed to accommodate the full and actual size of the tested samples of building materials used in the Syrian market to ease testing. Therefore, suitable samples do not have to be built for the apparatus; the thermal resistance is measured for many samples, and the results are compared with the thermal insulation code for buildings in the Syrian Arab Republic. The results show that the difference between the resistance values obtained from the experiments and the Syrian thermal insulation code is due to the materials used in the local markets and their non-compliance with the code. These materials need testing and quality control during the manufacturing process
Learning Representations for Face Recognition: A Review from Holistic to Deep Learning
Get PDFFor decades, researchers have investigated how to recognize facial images. This study reviews the development of different face recognition (FR) methods, namely, holistic learning, handcrafted local feature learning, shallow learning, and deep learning (DL). With the development of methods, the accuracy of recognizing faces in the labeled faces in the wild (LFW) database has been increased. The accuracy of holistic learning is 60%, that of handcrafted local feature learning increases to 70%, and that of shallow learning is 86%. Finally, DL achieves human-level performance (97% accuracy). This enhanced accuracy is caused by large datasets and graphics processing units (GPUs) with massively parallel processing capabilities. Furthermore, FR challenges and current research studies are discussed to understand future research directions. The results of this study show that presently the database of labeled faces in the wild has reached 99.85% accuracy
Increasing the Power Output of a PV Solar System by Using a Cooling-Reflector Assembly
Get PDFThere are various methods that can be employed to increase the lifespan and power output of photovoltaic (PV) systems. This study aims to increase the power output of a grid-connected PV system by using a water-cooling unit and solar reflectors. The PV modules of the current PV system are divided into two clusters. The first cluster, which is considered an improved cluster, has a solar reflector-cooling unit added to it, while the second cluster is used as a reference. The results show that the maximum efficiency and performance ratio values of the improved and reference PV modules at 10:30 AM are 14.7% & 13.7% and 97.5% & 91.2%, respectively. The maximum electrical power values of the improved and reference PV modules at 12:00 PM are 2.55 W and 1.69 W, respectively. The maximum gain value for electrical power is 43%
Behavior of Built-Up Cold-Formed Steel Stub Columns Infilled with Washed Bottom Ash Concrete
Get PDFThe main objective of the study is to determine the behavior of built-up cold-formed steel (CFS) stub columns infilled with washed bottom ash (WBA) concrete and also their failure mode. Five proportions of WBA as sand replacement in concrete and five specimens of built-up CFS stub columns infilled with WBA are produced in this study. There are four parts of the testing conducted: material properties of CFS, material properties of WBA concrete, mechanical properties of the connection, and mechanical behavior of built-up CFS stub columns. The result shows that the specimen with 25% WBA is reported to have the highest value of compressive strength in the material properties of WBA concrete and the mechanical behavior of built-up CFS stub column. The percentage difference of the ultimate load of the built-up CFS column filled with normal concrete and filled with WBA concrete is noted to have a range of 3% to 25%
A Novel Ultrasonic Method for Measuring the Position and Velocity of Moving Objects in 3D Space
Get PDFThis study proposes a method for concurrently determining the position and velocity of a moving object in three-dimensional (3D) space using echolocation. A spherical object, i.e., a flying ball, is used to demonstrate the ability of the proposed method. The position of the object is calculated using a time-of-flight (TOF) technique based on a cross-correlation function, which requires less computational time when using one-bit signal technology. The velocity of the object is subsequently computed from the length of chirp signals and the velocity vector measurements between the position of the object and the position of acoustical receivers. The coordinate of the object location is identified by the distance from the sound source to the object, the elevation angle, and the azimuth angle. The validity and repeatability of the experimental results are evaluated by statistical methods, showing ±1% of accuracy. It is concluded that the proposed method can identify the position and velocity of a rigid body in 3D space
Effects of Data Standardization on Hyperparameter Optimization with the Grid Search Algorithm Based on Deep Learning: A Case Study of Electric Load Forecasting
Get PDFThis study investigates data standardization methods based on the grid search (GS) algorithm for energy load forecasting, including zero-mean, min-max, max, decimal, sigmoid, softmax, median, and robust, to determine the hyperparameters of deep learning (DL) models. The considered DL models are the convolutional neural network (CNN) and long short-term memory network (LSTMN). The procedure is made over (i) setting the configuration for CNN and LSTMN, (ii) establishing the hyperparameter values of CNN and LSTMN models based on epoch, batch, optimizer, dropout, filters, and kernel, (iii) using eight data standardization methods to standardize the input data, and (iv) using the GS algorithm to search the optimal hyperparameters based on the mean absolute error (MAE) and mean absolute percent error (MAPE) indexes. The effectiveness of the proposed method is verified on the power load data of the Australian state of Queensland and Vietnamese Ho Chi Minh city. The simulation results show that the proposed data standardization methods are appropriate, except for the zero-mean and min-max methods
Limiting Reinforcement Ratios for Hybrid GFRP/Steel Reinforced Concrete Beams
Get PDFIn this work, a theoretical approach is proposed for estimating the minimum and maximum reinforcement ratios for hybrid glass fiber reinforced polymer (GFRP)/steel-reinforced concrete beams to prevent sudden and brittle failure as well as the compression failure of concrete before the tension failure of reinforcements. Equilibrium equations were used to develop a method for determining the minimum hybrid GFRP/steel reinforcement ratio. A method for determining the maximum hybrid GFRP/steel reinforcement ratio was also developed based on the equilibrium of forces of the balanced failure mode. For estimating the load-carrying capacity of concrete beams reinforced with hybrid GFRP/steel, less than the minimum and more than the maximum reinforcement ratio is recommended. Comparisons between the proposed expressions, experimental data, and available test results in the literature shows good agreement between the theoretical and experimental data, with a maximum discrepancy of 7%
Numerical and Experimental Study on the Grinding Performance of Ti-Based Super-Alloy
Get PDFThe experiments of the surface grinding of Ti-6Al-4V grade 5 alloy (Ti-64) with a resin-bonded cubic Boron Nitride (cBN) grinding wheel are performed in this research to estimate the influence of cutting parameters named workpiece infeed speed, Depth of Cut (DOC), cooling condition on the grinding force, force ratio, and specific energy. A finite element simulation model of single-grain grinding of Ti-64 is also implemented in order to predict the values of grinding forces and temperature. The experimental results show that an increase of workpiece infeed speed creates higher intensified cutting forces than the DOC. The grinding experiments under wet conditions present slightly lower tangential forces, force ratio, and specific energy than those in dry grinding. The simulation outcomes exhibit that the relative deviation of simulated and experimental forces is in the range of 1-15%. The increase in feed rate considerably reduces grinding temperature, while enhancement of DOC elevates the heat generation in the cutting zone
Planar EBG Loaded UWB Monopole Antenna with Triple Notch Characteristics
Get PDFA triple band-notched ultra-wideband (UWB) monopole antenna using a planar electromagnetic bandgap (EBG) design is proposed. The EBG unit cell composed by an Archimedean spiral and inter-digital capacitance demonstrates the notch frequencies. The antenna with EBG cells near the feed line occupies only 30 × 36 mm2 with triple band-rejection characteristics. The three notched bands at 4.2 GHz, 5.2 GHz, and 9.1 GHz can be used in C-band satellite downlink, wireless local area network (WLAN), and X-band radio location for naval radar or military required applications. In addition, the proposed design is flexible to tune different notched bands by altering the EBG dimensions. The parametric analysis is studied in details after placing the EBG unit cells near the feed line to show the coupling effect. The input impedance and surface current distribution analysis are also analyzed to understand the effect of EBG at notch frequencies. The proposed design prototype is fabricated and characterized. A fairly considerable agreement is observed between simulated and measured results
Hybrid Speed Controller Design Based on Sliding Mode Controller Performance Study for Vector Controlled Induction Motor Drives
Get PDFThe discontinuous control of the sliding mode control (SMC) law causes chattering phenomenon in system trajectories (the oscillation around the desired value), which results in various unwanted effects such as current harmonics and torque ripples. Therefore, this study aims to investigate the performance of a sliding mode speed controller for a three-phase induction motor (IM) controlled by a rotor flux orientation technique to obtain optimum performance. The study results show that the experimental control gains found in the control law have a clear effect on limiting chattering and the system response speed. According to the study results, a hybrid controller is designed based on the fuzzy logic control (FLC) approach to optimally tune these gains. The designed hybrid controller is verified by experimental approximation of simulations using Matlab/Simulink. The simulation results show that the hybrid controller reduces the chattering phenomenon and improves the system’s dynamic performance