International Journal of Engineering and Manufacturing @ijem
Статьи журнала - International Journal of Engineering and Manufacturing
Все статьи: 532
Статья научная
Muffler acts as noise reduction element on exhaust system. Noise from an automotive application is the major source of noise pollution. Here the transmission loss of central inlet and central outlet muffler of single expansion chamber has been compared and validated in three methods namely transfer matrix method, finite element analysis and an experimental method for this purpose an experimental setup has been built up which is based on two load method. Several researchers have worked in the area of noise attenuation on central inlet by changing the position of outlet as side outlet but no one emphasizes on offset of the central inlet and central outlet position. Thereafter the finite element analysis tool Ricardo wave 1-D and comsol multiphysics is used to evaluate transmission loss for various offset position of inlet and outlet duct of the muffler. The very purpose to improve the acoustic performance of central inlet with offset outlet pipe by measuring transmission loss of offset inlet with offset outlet with various positions by keeping same space. Finite element analysis shows that higher attenuation can be achieved by increasing offset distance of central inlet & outlet outlet towards radial direction of the expansion chamber with the variation of 0.2r, 0.4r and 0.6r. Here 'r' is radius of single expansion chamber. The result shows that high transmission loss can be achieved by increasing the offset radial distance of the inlet pipe and outlet pipe. Further higher attenuation can also be achieved in case of fixed the distance of offset inlet and outlet at 0.6r by rotating the offset outlet which is also offseted at 0.6r distance by 0o, 45o, 90o, 135o and 180o. On ward rotation from remaining 180o to 360o the behavior of wave propagation will be same what has been reflected between 0o to 180o. Transmission loss maximizes when the offset outlet is loacted at 90o. It clearly reveals that optimization can be achieved by using finite element analysis tool by using virtual protyping.
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Статья научная
The use of virtual keyboards in mobile devices such as smartphones and tablets has become an essential tool for inputting information. The sound of keystrokes has been observed in previous studies to be recorded along with ambient noises, such as those produced by uncontrolled student noise, fans, doors and windows, moving cars, and similar sources. The presence of such noises negatively affects the quality of the keystrokes signal, which in turn affects keystroke analysis. The traditional FFT-based denoising methods are vital but they are often limited by their inability to adapt to the varying characteristics of real-world audio and noises. This paper proposes an enhanced Fast Fourier Transform (FFT) with an adaptive threshold technique that reduces ambient noises. The adaptive threshold technique is developed to identify frequency bins that contain noise and set their sizes to zero or attenuate them to reduce the noise. The paper evaluates the performance of the enhanced FFT with adaptive threshold on keystrokes recorded audio and validates it through extensive experimentation. The results show that the enhanced FFT outperforms the traditional FFT in terms of speed and the amount of noise removed from the recorded audio signal, indicating a significant improvement.
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Epipolar Geometry Estimation for Wide Baseline Stereo
Статья научная
The epipolar geometry is the intrinsic projective geometry between two views, and the fundamental matrix is the algebraic representation of epipolar geometry. Recovery of epipolar geometry is a fundamental problem in computer vision. Its importance is due to the fact that it provides relationships between corresponding point in the two images. In this paper, the problem of automatic robust estimation of the epipolar geometry for wide-baseline image pair is addressed. this problem for wide-baseline image pair is difficult because the putative correspondences include a low percentage of inlier correspondences, and it could become a severe problem when the veridical data are themselves degenerate or near-degenerate. Base on our previous work, a topological clustering(TC) is proposed to apply to fundamental matrix estimating. The TC algorithm has been demonstrated to be able to effectively eliminate the mismatches and reserve the correct matches. This advantage is extremely important to speeds up the performance of the epipolar geometry estimation and avoid the degeneracy. First, a set of match clusters are generated from the initial SIFT matches using topological clustering algorithm. Then, all the valid pairs of clusters are used to generate a series of fundamental matrix estimates and the best estimate is chosen as the solution. Six famous image pairs are used to test the proposed algorithms and the comparison with the related methods has been conducted. The compared experiments emphasize the performance of the proposed CPC algorithms.
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Статья научная
The removal of hexavalent chromium [Cr(VI)] is a challenging task due to its acute toxicity even at low concentration. In the present study, a low-cost activated carbon (LAC) was prepared from desert date seed shell by chemical activation with H3PO4 and utilized for the removal of hexavalent chromium from aqueous solution. Batch experiments were conducted to investigate the influence of operating variables such as pH, contact time, adsorbent dosage, initial concentration, co-existing ions and temperature. The amount of Cr(VI) adsorbed was found to vary with solution pH and maximum adsorption was observed at a pH value of 2.0. The extent of chromium uptake (mg g-1) was found to increase with increase in initial concentration and contact time. The applicability of the four isotherm models for the present equilibrium data follows the sequence: Freundlich > Temkin > Langmuir > Dubinin-Radushkevich. The mean free energy from the Duninin-Radushkevic isotherm model hinted that the adsorption of Cr(VI) onto the adsorbent surface follows physisorption mechanism. Thermodynamic parameters related to adsorption, Gibbs free energy change (∆G°), enthalpy change (∆H°), entropy change (∆S°), were also calculated and the negative value of ∆H° indicates the exothermic nature of the adsorption process. The considerable adsorption capacity of 99.09 mg g-1 is a signifier of the suitability of the prepared adsorbent for commercial application. The findings implicated that the adsorbent can be employed in the treatment of Cr-bearing water and wastewater.
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Estimating Missing Security Vectors in NVD Database Security Reports
Статья научная
Detection and analysis of software vulnerabilities is a very important consideration. For this reason, software security vulnerabilities that have been identified for many years are listed and tried to be classified. Today, this process, performed manually by experts, takes time and is costly. Many methods have been proposed for the reporting and classification of software security vulnerabilities. Today, for this purpose, the Common Vulnerability Scoring System is officially used. The scoring system is constantly updated to cover the different security vulnerabilities included in the system, along with the changing security perception and newly developed technologies. Different versions of the scoring system are used with vulnerability reports. In order to add new versions of the published scoring system to the old vulnerability reports, all analyzes must be done manually backwards in accordance with the new security framework. This is a situation that requires a lot of resources, time and expert skill. For this reason, there are large deficiencies in the values of vulnerability scoring systems in the database. The aim of this study is to estimate missing security metrics of vulnerability reports using natural language processing and machine learning algorithms. For this purpose, a model using term frequency inverse document frequency and K-Nearest Neighbors algorithms is proposed. In addition, the obtained data was presented to the use of researchers as a new database. The results obtained are quite promising. A publicly available database was chosen as the data set that all researchers accepted as a reference. This approach facilitates the evaluation and analysis of our model. This study was performed with the largest dataset size available from this database to the best of our knowledge and is one of the limited studies on the latest version of the official scoring system published for classification of software security vulnerabilities. Due to the mentioned issues, our study is a comprehensive and original study in the field.
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Статья научная
In this paper, we consider one-parameter exponential family and obtain the Bayes and. empirical Bayes estimators of the unknown parameter based on record values under a precaution asymmetry entropy loss function. The admissibility and inadmissibility of a class of inverse linear estimators of are studied based on upper records.
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Estimation of One-parameter Exponential Family Under Entropy Loss Function Based on Record Values
Статья научная
In this paper, we consider one-parameter exponential family and obtain the minimum variance unbiased estimator , Bayes and empirical Bayes estimators of the unknown parameter based on record values under entropy loss function. The admissibility and inadmissibility of a class of inverse linear estimators are also discussed based on upper records.
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Experimental Study of Airlift Pump Performance with S-Shaped Riser Tube Bend
Статья научная
Airlift pump is a type of deep well pumps. Sometimes, it is used for removing water from mines or pumping slurry of sand and water or other solutions. The performance of airlift pump is affected by two sets of parameters; the geometrical and operational parameters. The geometrical parameters include pipe diameter, pump height, design of air injection system, and entrance geometry of the lifting pipe; while the operational parameters involve submergence ratio, conditions of injected air, and nature of lifted phase. Conventionally, airlift pump with bent riser tube is less efficient than that with vertically straight riser tube. However, in real life situations, the use of local riser tube bend or flexible riser tubes is considerably unavoidable. This work investigates experimentally the effects of local bends of the riser tube on the airlift pump performance. A series of experiments on a model airlift pump with three different riser tube configurations, based on the vertical position of local bends, were carried out. The local bends are in the form of an S-shaped like duct. The results showed that setting local bends of the riser tube near the air injection zone improves the airlift pump performance. However, improvement obtained in airlift pump performance is being negligible and, thus, the position of local bend of riser tube does not contribute to improvements in the performance of airlift pump.
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Exploratory Study on Hyperledger Fabric Framework: Food Supply Chain as a Case Study
Статья научная
The wide use of supply chain management systems in various business sectors encouraged researchers and those who were concerned to explore and employ efficient technologies to improve such systems. The integration of blockchain into supply chains has proved its effectiveness at increasing the customer’s trust level, as well as many other features, such as traceability, immutability, provenance awareness, etc. Moreover, the use of private permissioned blockchain networks, for instance Hyperledger Fabric (HLF), not only leverages the level of confidence, but also increases the speed of transaction execution. In this paper, an exploratory detailed study on Hyperledger Fabric framework is conducted. The study focused on the HLF network design, the consensus algorithms used in HLF, the HLF smart contracts and the transaction flow stages. Moreover, a number of illustrative case studies that used HLF into their networks designed for food supply chain management systems have been introduced. The basic design components in each of the applications are reviewed as well as the main goals and desired outcomes.
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Extraction of facial features for detection of human emotions under noisy condition
Статья научная
Affirmation of human faces out of still pictures or picture progressions is an as of now making research field. There are an extensive variety of engagements for structures adjusting to the issue of face limitation and affirmation e.g. exhibit based video coding, face conspicuous confirmation for security structures, look area, and human-PC connection. The acknowledgment and region of the face, and furthermore the extraction of facial features from the photos, are fundamental. In view of assortments in illumination, establishment, visual point and outward appearances, the issue becomes complicated. This paper presents a novel method to extract human facial features for the detection of human emotions (such as “sad”, “happy”, “sorrow” etc.) under noisy conditions. This whole work constitutes better working of a video surveillance system. For detection and extraction of facial features simple formulae are used to represent skin color models depending on the range of HSV (Hue, Saturation, Value) values used for the detection of human skin. Here HSV color model is used because it is fast as well as compatible with human color perception. Additionally, implementation of Probability Neural Network (PNN) enhances the working of the surveillance system. Utilization of PNN expands the ability of surveillance framework as it can give the yield image regardless of whether the information image contains noise in it. The proposed algorithm for the entire task is developed using MATLAB software along with suitable Image Processing Toolbox (IPT).
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Статья научная
As of late, Automatic speech recognition has advanced on account of instruments, for example, natural language processing, and deep learning, among others. It is a framework or put in another way, a gadget that changes a raw signal into computer comprehensible text. The genuine creation of speech is comprised of changes in air pressure that outcomes in pressure wave that our ear and cerebrum comprehend. The vocal tract is utilized to deliver a human speech, which is adjusted by teeth, tongue, and lips. Speech recognition alludes to a machine's ability to perceive human speech and transform it into a computer comprehensible text. Speech recognition is a magnificent illustration of good interaction between humans and computers. In this paper, we introduce the process to extricate the feature from the signal utilizing Mel-frequency cepstral coefficients. Mel-frequency cepstral coefficients are a genuinely far wide and proficient methodology for feature extraction from a sound file. This technique improved the speech recognition process and removes the distortion in the voice. In this manuscript we applied the Mel-frequency filtration process to improve speech and remove the background noise. the Therefore, the proposed methodology gives better performance in the automated speech recognition system.
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Fabrication of a Porous Ceramic Material Suitable for Cost-effective Thermal Insulation of Buildings
Статья научная
The domestication of cost-effective, green, and sustainable building materials is significant towards its massive adoption in the developing countries. The feasibility of developing porous ceramics for cost-effective thermal insulation of buildings was explored in this study using waste materials including granite shifting and sawdust as well as chemical reagents including water glass and sodium hydroxide. Granite shifting and sawdust were dried, processed into powdered form, milled and sieved. Samples of porous ceramics were formulated using varying percentages by weight of granite shifting and sawdust mixed with a constant percentage by weight of water glass and sodium hydroxide in three different cases. The homogenized powder of the formulated composition was uniaxially pressed at 10Mpa. The samples were dried and then sintered in a gas kiln at 8500C for 3 hours. The result revealed water absorption (21.1−56.5%), compressive strength (1.2−7.9Mpa), bulk density (1.44−1.81g/cm3), apparent porosity (38.1−81.3%), and thermal conductivity (0.13−0.54W/m.K). These results indicated that the obtained porous ceramics is a potential material for cost-effective thermal insulation of buildings where a suitable combination of thermal conductivity, porosity, and mechanical strength is required.
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Статья научная
The key of fast identification algorithm of time-varying modal parameter based on subspace tracking is to find efficient and fast subspace-tracking algorithm. This paper presents a new version of NIC(Novel Information Criterion) using two-layer linear neural network learning for subspace tracking. Comparing with the original algorithm, there is no need to set a key control parameter in advance. Simulation experiments show that new algorithm has a faster convergence in the initial period.
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Статья научная
As a result of the harmful effects of GHG on the environment, and the increase in fossil fuel prices, the world is currently searching for sustainable alternative energy sources instead of fossil fuels. Bangladesh is a country that has an ambitious aim to rely on sustainable energy. This study discusses the viability of a 100MW PV power project in Rajshahi, Bangladesh by using RETScreen software. This includes benchmarking, emissions analysis, and financial analysis. The power generation cost of the proposed PV power plant is 0.09 $/kWh based on the benchmark assessment and the annual power provided to the national power grid is determined to be 140,155MWh. According to the emission analysis, overall perspective emissions to the surroundings will be decreased by 78,797.7 tCO2 annually. The NPV and cumulative cash flow demonstrate good results based on the financial analysis. The outcome is, the proposed project is both financially and technically feasible, as well as environmentally beneficial, and will assist the government in meeting the aim of developing clean and sustainable energy.
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Fire and Motion Early Warning Device: Its Design and Development
Статья научная
Cases of theft and robbery of computers, CCTV equipment, and LCD projector have become more frequent in schools. In addition, fire hazards are great threat to educational institutions where expensive learning materials are kept. Such incidents could be lessened and avoided if schools are equipped with appropriate security systems capable of monitoring and informing people about the coming possible danger. Thus, the development of Fire and Motion Early Warning Device (FMEWD) is timely and relevant. FMEWD consists of a website and interconnected devices and sensors intended to provide an efficient and effective warning system for preventing incidents relating to fire, smoke, and intrusion within an office. Upon detection, the system automatically sends an email and SMS to registered users. This study used the Agile Development Model which allows features to be delivered quickly and more frequently with higher levels of predictability. Evidently, the integration of different technologies conceptualized by the researcher addresses the pressing security concerns faced by educational institutions like NEUST.
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Flexural Behavior of Reinforced Concrete Beams with High Performance Fibers
Статья научная
High-performance concrete is a specialized series of concrete designed to provide superior mechanical and physical properties that cannot be achieved through the conventional design. Using high-performance concrete in the construction field can reduce the dead weight, provide a longer span, and increase the service life. In this paper, a full experimental program is conducted to study the effect of glass and carbon fibers on the flexural behavior of reinforced concrete (RC) beams. A total of 15 RC beam specimens are prepared and divided into four main groups according to their added fiber materials, which are (S- Steel fiber), and E (E- Glass fiber), carbon fiber, and S-Glass with carbon fiber. All the reinforced fibers are used at 1.5% of the cement weight. The beams are reinforced using the fiber materials at the hinging zone then tested under concentrated static load placed at the mid-span. The results show that using high-performance fibers can improve the ultimate load capacity, ductility, and absorption energy of the RC beams.
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Статья научная
Most digital forensic investigations involve images presented as evidence. One of the common problems of these investigations is to prove the image's originality or, as a matter of fact, its manipulation. One of the guaranteed approaches to prove image forgery is JPEG double compressions. Double compression happens if a JPEG image is manipulated and saved again. Thus, the binaries of the image will be changed based on a “previous” quantization table. This paper presents a practical approach to detecting manipulated images using double JPEG compression analysis, implemented in a newly developed software tool. The method relies on an adaptive database of quantization tables, which stores all possible tables and generates new ones based on varying quality factors of recognized tables. The detection process is conducted through image metadata extraction, allowing analysis without the need for the original non-manipulated image. The tool analyzes the suspected image using chrominance, and luminance quantization tables utilizing the jpegio Python library. The tool recognizes camera sources as well as the programs used for manipulating images with the related compression rate. The tool has demonstrated effectiveness in identifying image manipulation, providing a useful tool for digital forensic investigations. The tool identified 96% of modified images whereas the other 4% identified as false positives. The tool fixes the false positives by extracting the software information from the image metadata. With a rich sources database, forensic examiners can use the proposed tool to detect manipulated evidence images using the evidence image only.
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Four-dimensional Vector Matrix Determinant and Inverse
Статья научная
The theory of two-dimensional matrix has been popularized in multi-dimensional matrix. However applications of multi-dimensional matrix also bring space redundancy and time redundancy, we put forward a multi-dimensional vector matrix model. This is new series of study to define multidimensional vector matrix mathematics, including four-dimensional vector matrix determinant, four-dimensional vector matrix inverse and related properties. There is innovative concept of multi-dimensional vector matrix mathematics created by author with numerous applications in engineering, math, video conferencing, 3D TV, and other fields.
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Fully Automated Hydroponics System for Smart Farming
Статья научная
This project is focused on developing a Fully Automatic Hydroponics system which helps in monitoring and controlling temperature, Humidity, pH and EC in Hydroponics. Hydroponics is a method of growing crops without soil. Plants are grown in rows or on trellises, just like in a traditional garden, but they have their roots in water rather than in dirt. Although, there are different ways in which hydroponics can be implemented, there is no individual system which can measure and control pH and EC level of nutrient solution along with its surrounding temperature and humidity automatically. We use PIC16F877A microcontroller and four pumps, three of which are used to pump water, nutrient solution, pH solution and the fourth pump is used to control the humidity. A fan is used to control the temperature which increases its speed as the temperature increases. The pumps are turned on depending on the EC and pH values obtained from the electrodes. A passive LCD display is used to display variations in the values. Different Analysis like water usage, plant growth in comparison with regular farming method and hydroponics is successfully completed which results in hydroponics system is significant method in comparison with soiled cultivation method in terms of yield and water usage. This project is expected to produce high yield crops by taking minimal space, makes work easier for farmers in growing of plants, and also consumes less amount of water when compared to traditional method resulting in conservation of water.
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Fuzzy Based Enhanced Smart Rest Room Automated Faucet System
Статья научная
Existing smart rest room automated faucet systems operate on traditional control theory, with absolute control value, irrespective of its degree of accuracy. For example, a hands-free hand wash basin may be programmed to release water when an object is about 2cm close to the infrared sensor. This absolute control value has pitfalls such as, ascertaining the quantity of water required for each operation, without activating the water flow switch to release water at maximum rate, leading to wastage of water resources. In order to develop an efficient and accurate smart rest room automated faucet system that will release water at an approximate quantity as required for varying condition, this research paper delves into employing a data-centric model for understanding and designing a smart rest room automated faucet system, that is more accurate in operation and properly utilizes water resources. To achieve this goal, we first designed a fuzzy model using MATLAB, for the proposed smart rest room automated faucet system, and then implemented the model on embedded atmel328 microcontroller, interfaced with an infrared obstacle sensor and an electronic flow control switch to automate rest room faucet activities. In order to understand and improve its operation, data logged from the system infrared sensor for 3cm distance, was mined for proper understanding of the system operational accuracy. During which the result indicated proper water utilization at various rate of water dispensation, as a function the nearness of the object to the sensor. This supports the improvement promised by the proposed system, when adopted in existing smart rest room automated faucet systems design and re-design.
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