bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing Market Development and Innovation Project Management Factors Using the PICEA-g Hybrid Evolutionary Multi-Criteria Decision Technique. The Calcimine Company Case Study
Authors: Ghaffari S. , Najafi A. , Jafari Eskandari M.
Published: November 2020

Project management includes the consideration of complex decision modes used in modern decision support techniques. The aim of this paper was to prioritize such factors and evaluate their effects on project management and optimal control. Their effect on management and optimal project control are evaluated in frame of a statistical hypothesis. A new algorithm, "IPICEA-g" is proposed for the assessment. A questionnaire is used for data collection distributed between 56 employees of the CALCIMINE Company. T-test, two-sentence test, ANP method, FUZZY SEAMATEL and the IPICEA-g hybrid algorithm, are employed for data analyzing. Results are further discussed and conclusions are drawn.
Effect of Soorh Metakaolin on Concrete Compressive Strength and Durability
Authors: Saand A. , Keerio M. A. , Bangwar D. K.
Published: November 2020

Concrete durability is a key aspect for forecasting the expected life time of concrete structures. In this paper, the effect of compressive strength and durability of concrete containing metakaolin developed from a local natural material (Soorh of Thatta Distict of Sindh, Pakistan) is investigated. Soorh is calcined by an electric furnace at 8000C for 2 hours to produce metakaolin. One mix of ordinary concrete and five mixes of metakaolin concrete were prepared, where cement is replaced by developed metakaolin from 5% to 25% by weight, with 5% increment step. The concrete durability was tested for water penetration, carbonation depth and corrosion resistance. The obtained outcomes demonstrated that, 15% replacement level of local developed metakaolin presents considerable improvements in concrete properties. Moreover, a considerable linear relationship was established between compressive strength and concrete durability indicators like water penetration, carbonation depth and corrosion resistance.
A Frequency Multiplier Based on Time Recursive Processing
Authors: Perisic D. M. , Zoric A. C. , Gavric Z.
Published: November 2020

This paper describes a digital frequency multiplier for a pulse rate. The multiplier is based on the recursive processing of the input and output periods and their time differences. Special emphasis is devoted to the techniques which provide the development of multipliers based on this principle. The circuit is defined by two system parameters. One is the ratio of two clock frequencies and the other is a division factor of a binary counter. The realization of the circuit is described. The region of the system parameters for the stable circuit is presented. The different aspects of applications and limitations in realization of the circuit are considered. All mathematical analyses are made using a Z transform approach. It is shown that the circuit can be also used in tracking and prediction applications. Computer simulations are performed to prove the correctness of the math and the whole approach.
Buckling Stability Assessment of Plates with Various Boundary Conditions Under Normal and Shear Stresses
Authors: Riahi F. , Behravesh A. , Yousefzadeh Fard M. , Armaghani A.
Published: November 2020

In the present paper, the buckling behavior of plates subjected to shear and edge compression is investigated. The effects of the thickness, slenderness ratio and plate aspect ratio are investigated numerically. Effects of boundary conditions and loadings are also studied by considering different types of supports and loading. Finally, the results of numerical methods are compared with the theoretical results. This work mainly investigates the buckling behavior of plates but also the capabilities of program of plate-buckling (PPB) and ABAQUS for performing linear and nonlinear buckling analyses. The results will be useful for engineers designing walls or plates that have to support intermediate floors/loads.
A Demand Estimation Algorithm for Inventory Management Systems Using Censored Data
Authors: Nikseresht A. , Ziarati K.
Published: November 2020

During the selling time horizon of a product category, a number of products may become unavailable sooner than others and the customers may substitute their desired product with another or leave the system without purchase. So, the recorded sales do not show the actual demand of each product. In this paper, a nonparametric algorithm to estimate true demand using censored data is proposed. A customer choice model is employed to model the demand and then a nonlinear least square method is used to estimate the demand model parameters without assuming any distribution on customer’s arrival. A simple heuristic approach is applied to make the objective function convex, making the algorithm perform much faster and guaranteeing the convergence. Simulated dataset of different sizes are used to evaluate the proposed method. The results show a 23% improvement in root mean square error between estimated and simulated true demand, in contrast to alternate methods usually used in practice.
Assessment of Electrical Safety Beliefs and Practices: A Case Study
Authors: Boubaker S. , Mekni S. , Jerbi H.
Published: November 2020

In this paper, the electrical safety beliefs and practices in Hail region, Saudi Arabia, have been assessed. Based on legislative recommendations and rules applied in Saudi Arabia, on official statistics regarding the electricity-caused accidents and on the analysis of more than 200 photos captured in Hail (related to electrical safety), a questionnaire composed of 36 questions (10 for the respondents information, 16 for the home safety culture and 10 for the electrical devices purchasing culture) has been devised and distributed to residents. 228 responses have been collected and analyzed. Using a scale similar to the one adopted for a university student GPA calculation, the electrical safety level (ESL) in Hail region has been found to be 0.76 (in a scale of 4 points) which is a very low score and indicates a poor electrical safety culture. Several recommendations involving different competent authorities have been proposed. Future work will concern the assessment of safety in industrial companies in Hail region.
A Quantitative Measure For Evaluating Project Uncertainty Under Variation And Risk Effects
Authors: Chenarani A. , Druzhinin E. A.
Published: November 2020

The effects of uncertainty on a project and the risk event as the consequence of uncertainty are analyzed. The uncertainty index is proposed as a quantitative measure for evaluating the uncertainty of a project. This is done by employing entropy as the indicator of system disorder and lack of information. By employing this index, the uncertainty of each activity and its increase due to risk effects as well as project uncertainty changes as a function of time can be assessed. The results are implemented and analyzed for a small turbojet engine development project as the case study. The results of this study can be useful for project managers and other stakeholders for selecting the most effective risk management and uncertainty controlling method.
A Review of Works on Shaped Charges
Authors: Ahmed M. , Malik A. Q.
Published: November 2020

Shaped charges are used to pierce hard targets in all three versions of warfare land, air and naval. High explosives compositions fillings produce a thin high velocity metal jet which is used for target damage. Shaped charges can efficiently damage tanks possessing thick armour protection, bunkers and aircraft and are also useful for attacking ships and submarines. Shaped charges have a very long history since the Second World War Theoretical modeling started with the steady state theory of Birkhoff in 1948, which was modified by the non-steady state theory known as PER theory of shaped charges. To review the development in the shaped charges three stages are defined. In the first stage development until 1990 is presented when shaped charge theory was fully developed and penetration predictions with fairly good accuracy were possible. In the second stage, review of the work carried out in the last decade of the 20th century is discussed. During this period experimental verification of different parameters was established. The third stage deals with all the work carried out in the 21st century (2000-2010), including tools for advanced diagnostics, new fabrication and inspection, as well as new liner materials were included. The anomalies occurred were resolved by further refinements in the theoretical models.
Development of an Amorphous Silica from Rice Husk Waste
Authors: Bangwar D. K. , Saand A. , Keerio M. A. , Soomro M. A. , Bhatti N.
Published: November 2020

This article presents a study on the development of amorphous silica from Rice Husk (RH) waste. For ascertaining the optimum proportion of temperature and burning duration required for the development of an amorphous silica from RH waste, different Rice Husk Ash (RHA) samples, i.e. RHA (500oC-1.5hr), RHA (500oC-2hr), RHA (600oC-1.5hr), RHA (600oC-2hr), RHA (700oC-1.5hr), RHA (700oC-2hr), RHA (800oC-1.5hr), RHA (800oC-2) and RHA (900oC-1hr) were extracted by burning the husk at different temperatures and durations. Energy Dispersive Spectrometry (EDS) analysis was carried out for ascertaining the existence of main and insignificant elements in the RHAs samples and it was noticed that the extracting of silicon dioxide (SiO2) was exclusively dependent on the temperature and burning duration. After EDS, X-ray Diffraction (XRD) analysis was used to find out the crystalline and non-crystalline nature of obtained silica at different temperatures and burning durations. Through EDS and XRD, it has been found that that the extracted Rice Husk Ash at the temperature of 800oC for 2hr is rich in amorphous SiO2 content, i.e. 91.74% which meets the requirements of ASTM 618-03 for a pozzolanic material.
Enhancing the HVRT and LVRT Capabilities of DFIG-based Wind Turbine in an Islanded Microgrid
Authors: Safaei A. , Hosseinian S. H. , Askarian Abyaneh H.
Published: November 2020

Doubly fed induction generator (DFIG) based wind turbines are very sensitive to grid voltage variations. Therefore, low-voltage-ride-through (LVRT) and high-voltage-ride-through (HVRT) capabilities are employed to improve DFIG performance during grid faults and voltage swell events. In this paper, a superconducting magnetic energy storage (SMES) device with a PWM voltage source converter and a DC-DC chopper is proposed to enhance the DFIG LVRT and HVRT capabilities in an islanded microgrid simultaneously. The simulation results demonstrate that the SMES absorbs or releases energy from/to the microgrid during voltage swell events and fault condition respectively and consequently, improves the DFIG performance and enhances the DFIG LVRT and HVRT capabilities. The effectiveness of the proposed method is validated through detailed simulations in PSCAD/EMTDC.
Sensitive Constrained Optimal PMU Allocation with Complete Observability for State Estimation Solution
Authors: Manam R. , Rayapudi S. R.
Published: November 2020

In this paper, a sensitive constrained integer linear programming approach is formulated for the optimal allocation of Phasor Measurement Units (PMUs) in a power system network to obtain state estimation. In this approach, sensitive buses along with zero injection buses (ZIB) are considered for optimal allocation of PMUs in the network to generate state estimation solutions. Sensitive buses are evolved from the mean of bus voltages subjected to increase of load consistently up to 50%. Sensitive buses are ranked in order to place PMUs. Sensitive constrained optimal PMU allocation in case of single line and no line contingency are considered in observability analysis to ensure protection and control of power system from abnormal conditions. Modeling of ZIB constraints is included to minimize the number of PMU network allocations. This paper presents optimal allocation of PMU at sensitive buses with zero injection modeling, considering cost criteria and redundancy to increase the accuracy of state estimation solution without losing observability of the whole system. Simulations are carried out on IEEE 14, 30 and 57 bus systems and results obtained are compared with traditional and other state estimation methods available in the literature, to demonstrate the effectiveness of the proposed method.
A Simple Measuring Model for Evaluating the Performance of Small Block Size Accesses in Lustre File System
Authors: Jayakumar N. , Kulkarni A. M.
Published: November 2020

Storage performance is one of the vital characteristics of a big data environment. Data throughput can be increased to some extent using storage virtualization and parallel data paths. Technology has enhanced the various SANs and storage topologies to be adaptable for diverse applications that improve end to end performance. In big data environments the mostly used file systems are HDFS (Hadoop Distributed File System) and Lustre. There are environments in which both HDFS and Lustre are connected, and the applications directly work on Lustre. In Lustre architecture with out-of-band storage virtualization system, the separation of data path from metadata path is acceptable (and even desirable) for large files since one MDT (Metadata Target) open RPC is typically a small fraction of the total number of read or write RPCs. This hurts small file performance significantly when there is only a single read or write RPC for the file data. Since applications require data for processing and considering in-situ architecture which brings data or metadata close to applications for processing, how the in-situ processing can be exploited in Lustre is the domain of this dissertation work. The earlier research exploited Lustre supporting in-situ processing when Hadoop/MapReduce is integrated with Lustre, but still, the scope of performance improvement existed in Lustre. The aim of the research is to check whether it is feasible and beneficial to move the small files to the MDT so that additional RPCs and I/O overhead can be eliminated, and read/write performance of Lustre file system can be improved.
3D-CFD Simulation of Confined Cross-Flow Injection Process Using Single Piston Pump
Authors: Elashmawy M.
Published: November 2020

Injection process into a confined cross flow is quite important for many applications including chemical engineering and water desalination technology. The aim of this study is to investigate the performance of the injection process into a confined cross-flow of a round pipe using a single piston injection pump. A computational fluid dynamics (CFD) analysis has been carried out to investigate the effect of the locations of the maximum velocity and minimum pressure on the confined cross-flow process. The jet trajectory is analyzed and related to the injection pump shaft angle of rotation during the injection duty cycle by focusing on the maximum instant injection flow of the piston action. Results indicate a low effect of the jet trajectory within the range related to the injection pump operational conditions. Constant cross-flow was used and injection flow is altered to vary the jet to line flow ratio (QR). The maximum jet trajectory exhibits low penetration inside the cross-flow. The results showed three regions of the flow ratio effect zones with different behaviors. Results also showed that getting closer to the injection port causes a significant decrease on the locations of the maximum velocity and minimum pressure.
Ductility Evaluation of Steel Structures with Reduced Beam Sections and Post-Tensioned Cables Using the Finite Element Method
Authors: Mehr E. H. , Saba H. R.
Published: November 2020

Given the importance of structure strengthening, this research introduces a particular type of steel structure in which the reduced beam section and post-tensioned cables were used for creating centralized property and preventing the formation of plastic hinges in the beam and columns. After introducing the system, ABAQUS modeling results are compared with a reliable laboratory sample to check its accuracy. Good convergence was seen which shows the modeling accuracy. The results of the model’s nonlinear static analysis revealed that the above steel structure has higher ductility when compared to conventional steel structures. Also, the results showed that with the rising of height, span length and early post-tensioned power of the cables we can increase the ductility of the structure.
Aspect Βased Classification Model for Social Reviews
Authors: Mir J. , Mahmood A. , Khatoon S.
Published: November 2020

Aspect based opinion mining investigates deeply, the emotions related to one’s aspects. Aspects and opinion word identification is the core task of aspect based opinion mining. In previous studies aspect based opinion mining have been applied on service or product domain. Moreover, product reviews are short and simple whereas, social reviews are long and complex. However, this study introduces an efficient model for social reviews which classifies aspects and opinion words related to social domain. The main contributions of this paper are auto tagging and data training phase, feature set definition and dictionary usage. Proposed model results are compared with CR model and Naïve Bayes classifier on same dataset having accuracy 98.17% and precision 96.01%, while recall and F1 are 96.00% and 96.01% respectively. The experimental results show that the proposed model performs better than the CR model and Naïve Bayes classifier.
Performance Analysis of Transient Current Limiters in a Distribution System
Authors: Shrivastav A. K. , Sadhu P. K. , Ganguly A.
Published: November 2020

This paper deals with the performance evaluation of a three-phase transient current limiter in distribution systems. A simulation model based on mathematical model of a three-phase, transient current limiter has been developed. The problem is formulated to justify the stable and harmonic free twelve-pulse and six-pulse converter based transient current limiter. Firstly, conventional methods like Bode Plot, Nyquist Plot and Nichols Chart are used to investigate the stability of twelve-pulse and six-pulse converter based transient current limiter. Next, a comparative analysis using fast Fourier transform is used to check the system harmonics using MATLAB simulation. The proposed design is found to be more efficient in making the system stable and harmonic free.
Health and Safety of Hyderabad Industries’ Labor. Causes and Awareness
Authors: Khoso A. R. , Akhund M. A. , Memon A. H. , Siddiqui F. , Khahro S. H.
Published: November 2020

Labor’s health and safety (H&S) is a matter of concern for all industries. Occurrence of accidents in industries is becoming a common issue. Both white collar and blue-collar workers are not shielded from materials that damage their health. This study identifies the critical factors affecting labor’s H&S in Hyderabad, Pakistan industries. The awareness of labor regarding prevention and consequences that affect workers’ H&S is also a matter of interest of this research. The severity of factors was determined through questionnaire survey from experts, H&S supervisors and managerial staff of industries. For the descriptive analysis the software SPPS 24.0 was used. This research also includes interviews form industry laborers about awareness regarding H&S critical factors. The results show that, Improper PPE use, operating machines that are poorly maintained, long term exposure to high intensity noise, working extended and irregular hours and lack of knowledge of working instruments are the critical causes of accidents. Also 60.9%, 73.9%, 69.6%, 78.3% and 89% of workers are not aware about these causes and their consequences. Thus, this research is a road map for industrial employers, law makers, local, provisional and federal Government of Pakistan in order to help minimizing the workplace accidents and the providing of safe and secure working environment for laborers.
Single Pile Settlement and Load Transfer Mechanism due to Excavation in Silty Clay
Authors: Soomro M. A. , Memon K. F. , Soomro M. A. , Memon A. , Keerio M. A.
Published: November 2020

In densely built areas, development of underground transportation system often involves excavations for basement construction and cut-and-cover tunnels which are sometimes inevitable to be constructed adjacent to existing piled foundations. In order to gain new insights into single pile responses (i.e. settlement and load transfer mechanism) to an adjacent excavation in saturated silty clay, a three-dimensional coupled- consolidation numerical analysis is conducted in this study. An advanced hypoplasticity (clay) constitutive model with small-strain stiffness was adopted. A linear increase in pile settlement was observed due to excavation-induced stress release. This is because part of the pile is placed within the boundaries of a major influence zone due to excavation-induced ground movement. Based on a settlement criterion, apparent loss of pile‘s capacity is 14%. A maximum bending moment of about 350 kNm is induced in the pile with the maximum deflection of 28 mm. In addition, mobilisation of shear strength at the pile-soil interface was found to be a key factor governing pile-soil-excavation interaction. During excavation, a downward load-transfer mechanism in the piles can be identified.
A Model For the Development οf Employees’ Learning (Career Path) in Industrial Enterprises
Authors: Chakamian Keshvari G. , Mohammadi Faraz J. , Safaie N. , Hosseini Nedjad S. J.
Published: November 2020

The goal of this study is to propose a model for the development of employees' learning (career path) in industrial enterprises. In the research a descriptive-survey method along with field research were used. The statistical population consists of all 110 employees of Dana Baspar's enterprises. A questionnaire with content verified by 30 experts along with the supervisor and the advisor was employed. Related validity of the questionnaires and their stability were 70%, counted by Cronbach's alpha, showing a good level of stability. Descriptive statistics for demographic data (frequency, standard deviation and mean) and inferential statistics were used. Research findings show that the influence of workshop and experimental skills gained by apprenticeship, the effect of training by holding meetings and seminars with experts or experience acquired during work is significant and positive on organizational productivity while the mediation variable of professional skills exists but the influence of classic and academic trainings is not positive and significant on organizational productivity considering the existence of mediation variables.
Performance Analysis and Comparison of Symmetrical and Asymmetrical Dual Stator Induction Generators for Wind Energy Conversion Systems
Authors: Singh R. , Verma V.
Published: November 2020

The emergence of micro/nano level wind generation has opened the research on induction generator (IG) topologies having easier and finer control available in multiphase generators. To establish the suitability of multiphase generators for wind generators the analysis of their performance based on the developed model for the same rating of six phase symmetrical (60˚) and asymmetrical (30˚) IGs is presented. A comparative performance evaluation of grid-excited six phase symmetrical and asymmetrical IGs also known as Dual Stator Induction Generators (DSIGs) is presented through simulation results in MATLAB/SIMULINK environment amidst load perturbations, limited variation of wind speed and perturbations in voltage and frequency of the non stiff micro-grid to which they are connected. Based on the performance indices like flux of direct and quadrature axis, speed variations, terminal voltage drop/rise, range of operational speed variation etc., a comparative analysis with the help of the results is drawn to establish the suitability of asymmetrical multiphase IGs for grid connected wind generators.
Using Fast Hot Shock Wave Consolidation Technology to Produce Superconducting MgB2
Authors: Gegechkori T. , Mamniashvili G. , Peikrishvili A. , Peikrishvili V. , Godibadze B.
Published: November 2020

The original hot shock wave assisted consolidation method combining high temperature was applied with the two-stage explosive process without any further sintering to produce superconducting materials with high density and integrity. The consolidation of MgB2 billets was performed at temperatures above the Mg melting point and up to 1000oC in partially liquid condition of Mg-2B blend powders. The influence of the type of boron (B) isotope in the composition on critical temperature and superconductive properties was evaluated. An example of a hybrid Cu-MgB2–Cu superconducting tube is demonstrated and conclusions are discussed.
SLA Management For Virtual Machine Live Migration Using Machine Learning with Modified Kernel and Statistical Approach
Authors: Hassan M. K. , Babiker A. , Baker M. , Hamad M.
Published: November 2020

Application of cloud computing is rising substantially due to its capability to deliver scalable computational power. System attempts to allocate a maximum number of resources in a manner that ensures that all the service level agreements (SLAs) are maintained. Virtualization is considered as a core technology of cloud computing. Virtual machine (VM) instances allow cloud providers to utilize datacenter resources more efficiently. Moreover, by using dynamic VM consolidation using live migration, VMs can be placed according to their current resource requirements on the minimal number of physical nodes and consequently maintaining SLAs. Accordingly, non optimized and inefficient VMs consolidation may lead to performance degradation. Therefore, to ensure acceptable quality of service (QoS) and SLA, a machine learning technique with modified kernel for VMs live migrations based on adaptive prediction of utilization thresholds is presented. The efficiency of the proposed technique is validated with different workload patterns from Planet Lab servers.
Reducing Torque Ripples of the Axial Flux PM Motors by Magnet Stepping and Shifting
Authors: Cetin E. , Daldaban F.
Published: November 2020

Higher efficiency on electric machines is the research goal of many studies. An example is the axial flux permanent magnet machines. These machines have some advantages like their watt/kg efficiency and torque density. This study aims to develop the performance characteristics of the axial flux permanent magnet machines. A new rotor magnet poles design in axial flux machines is suggested to mitigate the torque ripples. The method of stepping and shifting of the magnets is used. Two different designs are compared to verify the proposed approach. 3D finite element analysis is used for simulations. Torque ripple and back electromotive force waveforms are obtained from computer analysis. As a conclusion, the suggested method is found to be useable and mitigates the torque ripples. In addition to that, back EMF waveforms are turned to sinusoidal by the suggested design.
A Reactive Power Based Reference Model for Adaptive Control Strategy in a SEIG
Authors: Taghikhani M. A. , Farahani A. D.
Published: November 2020

In this paper, a new control strategy is proposed for a three-phase squirrel-cage self-excited induction generator (SEIG) connected to a variable speed wind turbine in autonomous mode. In order to improve the dynamic performance of the mentioned vector control system, a model reference adaptive controller is used for online rotor time constant estimation. Thus, the main drawbacks of this method, which include the effects of the changes in machine parameters on rotor flux estimation, slip speed, the creation of instability problems and the system leaving vector control mode, are resolved. In this control strategy, a PI controller is used to control the dc voltage and three similar hysteresis current controllers (HCC) are used to control the switching of IGBTs. The results of the dynamic simulation indicate the desirable performance of the proposed system.
A Cloud Associated Smart Grid Admin Dashboard
Authors: Naveen P. , Kiing Ing W. , Kobina Danquah M. , Sidhu A. S. , Abu-Siada A.
Published: November 2020

Intelligent smart grid system undertakes electricity demand in a sustainable, reliable, economical and environmentally friendly manner. As smart grid involves, it has the liability of meeting the changing consumer needs on the day-to-day basis. Modern energy consumers like to vivaciously regulate their consumption patterns more competently and intelligently than current provided ways. To fulfill the consumers’ needs, smart meters and sensors make the grid infrastructure more efficient and resilient in energy data collection and management even with the ever-changing renewable power generation. Though cloud acts as an outlet for the energy consumers to retrieve energy data from the grid, the information systems available are technically constrained and not user-friendly. Hence, a simple technology enabled utility-consumer interactive information system in the form of a dashboard is presented to cater the electric consumer needs.
Effect of Friction Stir Welding Parameters on the Microstructure and Mechanical Properties of AA2024-T4 Aluminum Alloy
Authors: El-Morsy A. W. , Ghanem M. , Bahaitham H.
Published: November 2020

In this work, the effects of rotational and traverse speeds on the 1.5 mm butt joint performance of friction stir welded 2024-T4 aluminum alloy sheets have been investigated. Five rotational speeds ranging from 560 to 1800 rpm and five traverse speeds ranging from 11 to 45 mm/min have been employed. The characterization of microstructure and the mechanical properties (tensile, microhardness, and bending) of the welded sheets have been studied. The results reveal that by varying the welding parameters, almost sound joints and high performance welded joints can be successfully produced at the rotational speeds of 900 rpm and 700 rpm and the traverse speed of 35 mm/min. The maximum welding performance of joints is found to be 86.3% with 900 rpm rotational speed and 35 mm/min traverse speed. The microhardness values along the cross-section of the joints show a dramatic drop in the stir zone where the lowest value reached is about 63% of the base metal due to the softening of the welded zone caused by the heat input during joining.
Influence of Material and Geometrical Properties of Permanent Magnets on Cogging Torque of BLDC
Authors: Yildirim M. , Kurum H. , Miljavec D. , Corovic S.
Published: November 2020

Aim of this study is to investigate the influence of both material and geometrical properties of surface mounted permanent magnets (PM) on cogging torque of a brushless DC motor (BLDC) by means of numerical modeling based on finite element method (FEM). To this end, a 2D numerical model of the BLDC motor is built by using the software package Ansys Maxwell. In this study, we analyze the machine properties in no excitation mode (i.e. no stator current is applied) and calculate the distribution of magnetic flux density within the entire motor, the magnetic flux density in the air gap, the cogging torque and the back electromotor force (EMF). Firstly, analysis is performed for four different magnets. It is seen that while cogging torque, back EMF, and magnetic flux density in the air gap for the strongest magnet material have the highest values, the lowest values of these are obtained for the weakest magnet. In the second part of the study, the effect of variation of magnet geometry on the cogging torque, magnetic field density and back EMF of BLDC is examined. Three magnet embrace values are handled in this study. When the magnet embrace increases, the value of the cogging torque reduces. Besides, the maximum values of the back EMF are approximately the same for different magnet embraces, while shapes of the back EMF only change based on the magnet embrace. According to the results, the cogging torque strongly depends on the material and geometrical properties of the magnets.
Electric Field Simulation Around Contaminated SIR Insulators Using MATLAB
Authors: Satheesh G. , Basavaraja B. , Nirgude P. M.
Published: November 2020

High voltage insulators are mainly used to support transmission lines. This paper focuses on simulating the electric field along the surface of contaminated Silicone Rubber (SIR) insulators. The electric field (EF) distribution is important to determine the EF stress occurring on the insulator surface. So, the EF distribution is analyzed using a FEM tool in MATLAB under various conditions. Two types of insulators, straight and alternate sheds, were considered. Results showed that higher EF stresses occurs on the trunk portions of both straight shed and alternate shed types. Also, the results showed higher EF magnitude on the straight shed compared to the alternate shed, under both clean and contamination conditions.
Color Channel Characteristics (CCC) for Efficient Digital Image Forensics
Authors: Gupta S. , Mohan N.
Published: November 2020

Digital image forgery has become extremely easy as low-cost image processing programs are readily available. Digital image forensics is a science of classifying images as authentic or manipulated. This paper aims at implementing a novel digital image forensics technique by exploiting an image’s Color Channel Characteristics (CCC). The CCCs considered are the noise and edge characteristics of the image. Averaging, median, Gaussian and Wiener filters along with Sobel, Canny, Prewitt and Laplacian of Gaussian (LoG) edge detectors are applied to get the noise and texture features. A complete, no reference, blind classifier for image tamper detection has been proposed and implemented. The proposed CCC classifier can detect copy-move as well as image splicing accurately with lower dimensionality. Support Vector Machine is used for classification of images as authentic or tampered. Experimental results have shown that the proposed technique outperforms the existing ones and may serve as a complete tool for digital image forensics.
Taxonomy of Fuzzy Multi-Attribute Decision Making Systems in Terms of Model, Inventor and Data Type
Authors: Umar R. , Sunardi . , Fitriana Y. B.
Published: November 2020

Decision support systems are one of the choices decision-makers make in an attempt to cope with the problems related to the time length required in decision-making process. Such systems are known to improve the efficiency and accuracy in the decision-making processes. In developing a decision support system, a certain calculation method is required as part of its processing. One of the most commonly used methods is FMADM. This research discusses the clustering of decision support system using FMADM in an attempt to provide a taxonomy of decision support system based on FMADM.
Further Research on an Anti-Swing Control System for Overhead Cranes
Authors: Spruogis B. , Jakstas A. , Gican V. , Turla V. , Moksin V.
Published: November 2020

A method of reducing load oscillations that occur when overhead crane reaches destination position is presented in the article. The use of control drive scheme of crane bridge and trolley that ensures a smooth phase trajectory transition of the load to the optimum trajectory in accordance with Pontryagin's maximum principle is proposed. Mentioned control system changes the magnitude or direction of the traction force at the moment when the load is located above the destination. It is found that the degree of change of the traction force depends on the hoisting rope deviation angle from vertical. This study was conducted in order to provide more accurate and fast handling of loads by overhead crane.
A Global Online Handwriting Recognition Approach Based on Frequent Patterns
Authors: Gmati C. , Amiri H.
Published: November 2020

In this article, the handwriting signals are represented based on geometric and spatio-temporal characteristics to increase the feature vectors relevance of each object. The main goal was to extract features in the form of a numeric vector based on the extraction of frequent patterns. We used two types of frequent motifs (closed frequent patterns and maximal frequent patterns) that can represent handwritten characters pertinently. These common features patterns are generated from a raw data transformation method to achieve high relevance. A database of words consisting of two different letters was created. The proposed application gives promising results and highlights the advantages that frequent pattern extraction algorithms can achieve, as well as the central role played by the “minimum threshold” parameter in the overall description of the characters.
Microscopical Characterization of Cast Hypereutectic Al-Si Alloys Reinforced with Graphene Nanosheets
Authors: Alghamdi A. S. , Ramadan M. , Abdel Halim K. S. , Fathy N.
Published: November 2020

This paper illustrates the effects of stirring and graphene nanosheet (GNS) addition on the microstructure and mechanical behaviour of 393 hypereutectic Al-Si alloys used in the diesel engine pistons. Two processing routes were applied to fabricate hypereutectic Al-Si alloys: The first route mainly depends on stirring Al-Si alloys for 12 minutes at 400 rpm. The second one involves stirring Al-Si alloys for 2 minutes and then adding graphene nanosheets into the vortex, and consequently continue stirring for 10 minutes at 400 rpm. Results show that the distribution of the primary silicon was improved significantly in stir casting at both the edge and the center of the samples with relative reduction of 34% and 37% in the average particle size respectively. This average primary silicon size was further reduced by 17% with the addition of 1 wt% GNSs. GNS embedding into Al-Si alloy matrix resulted in remarkable increase in hardness values of the nanocomposites compared to the cast alloy.
Developing an Algorithm to Consider Mutliple Demand Response Objectives
Authors: Behrens D. , Schoormann T. , Knackstedt R.
Published: November 2020

Due to technological improvement and changing environment, energy grids face various challenges, which, for example, deal with integrating new appliances such as electric vehicles and photovoltaic. Managing such grids has become increasingly important for research and practice, since, for example, grid reliability and cost benefits are endangered. Demand response (DR) is one possibility to contribute to this crucial task by shifting and managing energy loads in particular. Realizing DR thereby can address multiple objectives (such as cost savings, peak load reduction and flattening the load profile) to obtain various goals. However, current research lacks algorithms that address multiple DR objectives sufficiently. This paper aims to design a multi-objective DR optimization algorithm and to purpose a solution strategy. We therefore first investigate the research field and existing solutions, and then design an algorithm suitable for taking multiple objectives into account. The algorithm has a predictable runtime and guarantees termination.
Numerical Investigation of the Physical Properties Effect on the Thermal Performance of a Vertical Geothermal Heat Exchanger
Authors: Benyoub M. , Aour B. , Bouhacina B. , Sadek K.
Published: November 2020

Low-temperature geothermal energy is a promising technique for heating and cooling residential and commercial premises, especially since it is one of the green energy solutions that respect the environment. The principle of this technique is based on thermal exchange between the heat pump and the basement using a vertically buried heat exchanger. This is usually made of a U-shaped tube inserted vertically in a borehole made in the ground and filled with a filler material. The purpose of the present study is to vary the different construction materials of the U-tube, the filling material and the soil, in order to obtain the most energy-efficient parameters. The evolution of temperature and heat flux as a function of time has been highlighted for different combinations. Knowing that an experimental study requires a considerable monetary fund, the present model has been validated using previously literature results. Recommendations on the choice of different materials of the geothermal heat exchanger are proclaimed at the end of this work.
Determining the Critical Success Factors for Highway Construction Projects in Pakistan
Authors: Sohu S. , Jhatial A. A. , Ullah K. , Lakhiar M. T. , Shahzaib J.
Published: November 2020

The success of construction projects is not only crucial to stakeholders but also for the country’s economic and social development. Critical success factors (CSFs) are considered as key to project management practices wich can lead to a construction project success. The aim of this research is to determine and rank the CSFs of highway construction projects in Pakistan. A deep literature review was carried out to determine a set of CSFs for construction projects. After that, a questionnaire based on found CSFs was designed and distributed among construction experts working in highway construction projects of Pakistan. Out of 250 distributed questionnaires, 130 were received completed and validated. Gathered data was analyzed through statistical software SPSS, and critical success factors were ranked based on their mean value. As a result, experienced project management team, effective site management, commitment of all parties to the project, experienced design team, and proper project planning have been determined as the top five critical success factors for highway projects in Pakistan. The findings of this research would help construction practitioners in understanding CSFs and to improve project performance.
Frequency Estimation of Irregularly Sampled Data Using a Sparsity Constrained Weighted Least-Squares Approach
Authors: Zahedi A. , Kahaei M. H.
Published: November 2020

In this paper, a new method for frequency estimation of irregularly sampled data is proposed. In comparison with the previous sparsity-based methods where the sparsity constraint is applied to a least-squares fitting problem, the proposed method is based on a sparsity constrained weighted least-squares problem. The resulting problem is solved in an iterative manner, allowing the usage of the solution obtained at each iteration to determine the weights of the least-squares fitting term at the next iteration. Such an appropriate weighting of the least-squares fitting term enhances the performance of the proposed method. Simulation results verify that the proposed method can detect the spectral peaks using a very short data record. Compared to the previous one, the proposed method is less probable to miss the actual spectral peaks and exhibit spurious peaks.
Ground Water Quality Assessment of Daur Taluka, Shaheed Benazir Abad
Authors: Keerio M. A. , Bhatti N. , Samo S. R. , Saand A. , Bhuriro A. A.
Published: November 2020

The aim of this study was to assess the ground water quality of Daur Taluka of district Shaheed Benazir Abad for drinking purposes. Forty groundwater samples were collected from different locations and brought to Pakistan Council of Research in Water Resources (PCRWR) for analyzing various groundwater physical, chemical and biological parameters. The results of this study revealed that color, pH, magnesium, alkalinity and nitrate of all samples were found within the permissible limits of World Health Organization (WHO). Analytical results revealed that the percentage of samples that were beyond WHO standards was 15% regarding taste, 42.5% regarding TDS, 20% regarding chlorine, 12.5% regarding sulfate 12.5 regarding sodium and 32.5% regarding hardness. Microbiological contamination was found positive in the 25% of samples. The findings of this study revealed that the most (82.5%) of the samples of the study area belong to the category of hard to very hard water and their nature were alkaline.
An Anisotropic Elastic-plastic Model for the Optimization of a Press Machine’s Auxiliary Worktable Plate Thickness
Authors: Rajhi W. , Ayadi B. , Alghamdi A. , Messaoudene N.
Published: November 2020

In this work an anisotropic elastic–plastic finite element model strongly coupled with ductile damage is applied to determine the suitable thickness of added auxiliary worktable plate to a 100 ton maximum capacity press machine. The major focus of this study is to minimize the amount of stress transmitted to the optional worktable plate and the press machine body while allowing them to withstand plastic deformation and damage during compression testing until final sample fracture. The worktable plates and the press machine body are made of TRIP800 grade steel. AISI 316L stainless steel is chosen as test material for the cylindrical billets. The proposed model is based on a non-associative plasticity theory and the “Hill 1948” quadratic (equivalent) stress norm is considered to describe the large plastic anisotropic flow accounting for mixed isotropic and kinematic hardening with isotropic damage effect. For each material the model uses an experimental data base obtained from a set of tensile tests conducted until the final fracture in three directions, the rolling direction (RD) or 0, the transverse direction (TD) or 90, and the 45 direction. After several numerical simulations of compression testing using ABAQUS/Explicit FE® software, thanks to the user’s developed VUMAT subroutine, varying cylindrical billet diameters and material, worktable plates number and thicknesses and spatial plate configurations the solution of 100mm thick worktable plate is selected since in that case the cylinder specimen is totally damaged and the stress state inside the worktable plates and the press machine body remains admissible.
Simulation and Experimental Verification of a HB-Type Vernier Motor
Authors: Thejel R. H. , Hairik H. A. , Alwan M. A.
Published: November 2020

Direct drive motors are used as actuators in numerous applications in which they must rotate at low speeds with high torque and low torque ripple. Various types of vernier motors have been studied recently. The HB type vernier motor is one of them. Its rotor structure is the same as in a HB type stepping motor but has a field winding at the rotor and has multiphase windings in the stator. In the present work, a Matlab simulation of a HB type vernier motor is presented. To validate the motor results and response, the authors fabricated the motor and implemented its drive circuit. The motor was tested for different load conditions. Experimental results are found identical to simulation results and it is also shown that the motor has low torque ripple.
A Comparative Analysis of Classification Algorithms on Diverse Datasets
Authors: Alghobiri M.
Published: November 2020

Data mining involves the computational process to find patterns from large data sets. Classification, one of the main domains of data mining, involves known structure generalizing to apply to a new dataset and predict its class. There are various classification algorithms being used to classify various data sets. They are based on different methods such as probability, decision tree, neural network, nearest neighbor, boolean and fuzzy logic, kernel-based etc. In this paper, we apply three diverse classification algorithms on ten datasets. The datasets have been selected based on their size and/or number and nature of attributes. Results have been discussed using some performance evaluation measures like precision, accuracy, F-measure, Kappa statistics, mean absolute error, relative absolute error, ROC Area etc. Comparative analysis has been carried out using the performance evaluation measures of accuracy, precision, and F-measure. We specify features and limitations of the classification algorithms for the diverse nature datasets.