bluuebunny/crossref_metadata_2025 huggingface dataset:
Proximity-induced anisotropic magnetoresistance in magnetized topological insulators
Authors: Sklenar Joseph , Zhang Yingjie , Jungfleisch Matthias Benjamin , Kim Youngseok , Xiao Yiran , MacDougall Gregory J. , Gilbert Matthew J. , Hoffmann Axel , Schiffer Peter , Mason Nadya
Published: June 2021

Topological insulators (TIs) host spin-momentum locked surface states that are inherently susceptible to magnetic proximity modulations, making them promising for nano-electronic, spintronic, and quantum computing applications. While much effort has been devoted to studying (quantum) anomalous Hall effects in magnetic magnetically doped TIs, the inherent magnetoresistance (MR) properties in magnetic proximity-coupled surface states remain largely unexplored. Here, we directly exfoliate Bi2Se3 TI flakes onto a magnetic insulator, yttrium iron garnet, and measure the MR at various temperatures. We experimentally observe an anisotropic magnetoresistance that is consistent with a magnetized surface state. Our results indicate that the TI has magnetic anisotropy out of the sample plane, which opens an energy gap between the surface states. By applying a magnetic field along any in-plane orientation, the magnetization of the TI rotates toward the plane and the gap closes. Consequently, we observe a large (∼6.5%) MR signal that is attributed to an interplay between coherent rotation of magnetization within a topological insulator and abrupt switching of magnetization in the underlying magnetic insulator.
Characterization of an RF excited broad beam ion source operating with inert gases
Authors: Rohkamm Erik , Spemann Daniel , Scholze Frank , Frost Frank
Published: June 2021

Ion current density distributions, mass spectra, and ion energy distribution functions (IEDFs) for the use of Ar and mixtures of Ar/He and Ar/Ne in an RF broad beam ion source have been measured as a function of the extracted ion beam current and the applied RF-power. For the measurements, an array of Faraday probes and an energy-selective mass spectrometer have been used. Regardless of the gases or gas mixtures used, a broadening of the ion current density profile is measured at constant grid voltages with increasing RF-power. The IEDFs of all species are also dependent on the applied RF-power and show a bimodal shape with an increasing energy shift for a higher RF-power. The data show a significant contribution of charge exchange processes after the ions left the ion beam source. Besides ions of the process gas, additional species of ions originating from the erosion processes of the ion beam source, can be found in the mass spectrum. The measurements show that the operating conditions of the ion source have a significant influence on the beam properties and thus can also affect the results of ultraprecise ion beam-assisted processes.
Compact atomic descriptors enable accurate predictions via linear models
Authors: Zeni Claudio , Rossi Kevin , Glielmo Aldo , de Gironcoli Stefano
Published: June 2021

We probe the accuracy of linear ridge regression employing a three-body local density representation derived from the atomic cluster expansion. We benchmark the accuracy of this framework in the prediction of formation energies and atomic forces in molecules and solids. We find that such a simple regression framework performs on par with state-of-the-art machine learning methods which are, in most cases, more complex and more computationally demanding. Subsequently, we look for ways to sparsify the descriptor and further improve the computational efficiency of the method. To this aim, we use both principal component analysis and least absolute shrinkage operator regression for energy fitting on six single-element datasets. Both methods highlight the possibility of constructing a descriptor that is four times smaller than the original with a similar or even improved accuracy. Furthermore, we find that the reduced descriptors share a sizable fraction of their features across the six independent datasets, hinting at the possibility of designing material-agnostic, optimally compressed, and accurate descriptors.
Contribution of dipolar bridging to phospholipid membrane interactions: A mean-field analysis
Authors: Buyukdagli Sahin , Podgornik Rudolf
Published: June 2021

We develop a model of interacting zwitterionic membranes with rotating surface dipoles immersed in a monovalent salt and implement it in a field theoretic formalism. In the mean-field regime of monovalent salt, the electrostatic forces between the membranes are characterized by a non-uniform trend: at large membrane separations, the interfacial dipoles on the opposing sides behave as like-charge cations and give rise to repulsive membrane interactions; at short membrane separations, the anionic field induced by the dipolar phosphate groups sets the behavior in the intermembrane region. The attraction of the cationic nitrogens in the dipolar lipid headgroups leads to the adhesion of the membrane surfaces via dipolar bridging. The underlying competition between the opposing field components of the individual dipolar charges leads to the non-uniform salt ion affinity of the zwitterionic membrane with respect to the separation distance; large inter-membrane separations imply anionic excess, while small nanometer-sized separations favor cationic excess. This complex ionic selectivity of zwitterionic membranes may have relevant repercussions on nanofiltration and nanofluidic transport techniques.
Magnonic control of the superconducting spin valve by magnetization reorientation in a helimagnet
Authors: Gusev N. A. , Dgheparov D. I. , Pugach N. G. , Belotelov V. I.
Published: June 2021

We propose a method to control a bilayer superconducting spin valve (SSV) which does not perturb its superconducting state and is suitable for energy saving cryogenic electronics. This SSV consists of a superconducting layer and a helimagnetic layer of B20 family compounds, namely, Nb and spiral antiferromagnet MnSi. Thanks to unique properties of MnSi—broken inversion symmetry and cubic crystal lattice—there are a few ground state magnetic configurations with different directions of the magnetic spiral, divided by a potential barrier. Superconductivity in such a bilayer is controlled by the reorientation of the spiral vector in the MnSi layer, which leads to a change in the critical temperature of the Nb layer due to the proximity effect. The switching is proposed to be carried out by a several hundred ps in duration magnetic field pulse of several kOe in magnitude. Such a pulse does not destroy the superconducting state of the Nb layer by itself but leads to the excitation of magnons in the MnSi layer, which triggers the reorientation process of the magnetic spiral. After the completion of this process, the Nb layer switches into a normal state. Inverse switching returns the spiral to the initial state, opening the valve and turning on the superconducting state. The system can be switched there and back by a magnetic field of opposite signs along one direction in the layers plane, which allows an easy control. The switching time is estimated as several nanoseconds, which coincides with the scales of the STT-MRAM recording time.
Torsional fracture of viscoelastic liquid bridges
Authors: Chan San To , van Berlo Frank P. A. , Faizi Hammad A. , Matsumoto Atsushi , Haward Simon J. , Anderson Patrick D. , Shen Amy Q.
Published: June 2021

Significance

Dispensing of viscoelastic fluids is common in applications like electronic packaging, food engineering, and additive manufacturing. However, viscoelasticity leads to problems like slow liquid bridge breakup, stringiness, and satellite droplets generation. By high-speed imaging and numerical simulation, we show that torsion can break short, capillary stable liquid bridges in the order of 1 s. The underlying mechanism is edge fracture, an often undesired viscoelastic flow instability characterized by the sudden indentation of the fluid’s free surface when the fluid is subjected to shear. Our study represents an attempt to take advantage of edge fracture to benefit practical applications, potentially leading to improved fluid dispensing protocols.
Linearization constraints on sentential negation in Russian Sign Language are prosodic
Authors: Rudnev Pavel , Kuznetsova Anna
Published: June 2021

This squib documents exceptions to the main strategy of expressing sentential negation in Russian Sign Language (RSL). The postverbal sentential negation particle in RSL inverts the basic SVO order characteristic of the language turning it into SOV (Pasalskaya 2018a). We show that this reversal requirement under negation is not absolute and does not apply to prosodically heavy object NPs. The resulting picture accords well with the view of RSL word order laid out byKimmelman (2012)and supports a model of grammar where syntactic computation has access to phonological information (Kremers 2014;Bruening 2019).
Regular black holes and gravitational particle-like solutions in generic DHOST theories
Authors: Baake Olaf , Charmousis Christos , Hassaine Mokhtar , San Juan Miguel
Published: June 2021

We construct regular, asymptotically flat black holes of higher order scalar tensor (DHOST) theories, which are obtained by making use of a generalized Kerr-Schild solution generating method. The solutions depend on a mass integration constant, admit a smooth core of chosen regularity, and generically have an inner and outer event horizon. In particular, below a certain mass threshold, we find massive, horizonless, particle-like solutions. We scan through possible observational signatures ranging from weak to strong gravity and study the thermodynamics of our regular solutions, comparing them, when possible, to General Relativity black holes and their thermodynamic laws.
Density functional theory investigation on lattice dynamics, elastic properties and origin of vanished magnetism in Heusler compounds CoMnVZ (Z = Al, Ga)*
Authors: Li Guijiang , Liu Enke , Liu Guodong , Wang Wenhong , Wu Guangheng
Published: June 2021

The lattice dynamics, elastic properties and the origin of vanished magnetism in equiatomic quaternary Heusler compounds CoMnVZ (Z = Al, Ga) are investigated by first principle calculations in this work. Due to the similar constituent atoms in CoMnVAl and CoMnVGa compounds, they are both stable in LiMgPdSn-type structure with comparable lattice size, phonon dispersions and electronic structures. Comparatively, we find that CoMnVAl is more structurally stable than CoMnVGa. Meanwhile, the increased covalent bonding component in CoMnVAl enhances its mechanical strength and Vickers hardness, which leads to better comprehensive mechanical properties than those of CoMnVGa. Practically and importantly, structural and chemical compatibilities at the interface make non-magnetic semiconductor CoMnVAl and magnetic topological semimetals Co2MnAl/Ga more suitable to be grown in heterostructures. Owing to atomic preferential occupation in CoMnVAl/Ga, the localized atoms Mn occupy C (0.5, 0.5, 0.5) Wyckoff site rather than B (0.25, 0.25, 0.25) and D (0.75, 0.75, 0.75) Wyckoff sites in LiMgPdSn-type structure, which results in symmetric band filling and consequently drives them to be non-magnetic. Correspondingly, by tuning localized atoms Mn to occupy B (0.25, 0.25, 0.25) or/and D (0.75, 0.75, 0.75) Wyckoff sites in off-stoichiometric Co–Mn–V–Al/Ga compounds and keeping the total valence electrons as 24, newly compensated ferrimagnetic compounds are theoretically achieved. We hope that our work will provide more choices for spintronic applications.
Survey on Enhanced Security Control measures in Cloud Computing systems
Authors: Abbas Haider Hadi , Jaaz Zahraa A. , Al_Barazanchi Israa , Abdulshaheed Haider Rasheed
Published: June 2021

Cloud Computing System is an internet based network of systems that provides a wide range of services to various companies and individuals, creating a digital environment for business progressing for a better world. Cloud Computing delivers a variety of services like remote storage, database management, applications and software, and high power computing performance, all these can be easily attained by subscribing to the cloud service, such that even from a low end PC system, any high end software can be run easily through means of internet. But, providing security to all of these services and stored data of private organizations has always been a challenge. Once a cloud server has been hacked, or an intruder has authorized himself into the server, he can simply sabotage, steal or misuse any sort of information of the client companies stored in within the server’s database. There are many ways to provide security to the different parts of the cloud, some methods are impenetrable, while some are fragile and can be broken through. This paper focusses on the various aspects of the cloud and its security functionalities, and how these security functionalities can be improvised. Some security measures can only protect the cloud by updating and regulating their terms and conditions, and some measures include various authorization methods and regularized access to cloud services.
Revised Tower Earthing Design in High-Voltage Transmission Network for High-Frequency Lightning Condition
Authors: Mohamad A. , Yahaya M.P. , Hudi N.S.
Published: June 2021

Tower earthing system for transmission grid is designed to protect the working personnel and equipment, as well as to maintain the quality of supply during fault. The existing tower earthing system for towers in TNB’s grid is catered for normal power frequency (low-frequency) fault conditions. This earthing design is found to be inapt for transient nature of lightning condition to a certain extent, which involves a high-frequency domain. The current earthing practice of installing the electrodes radially in 60 m straight horizontal lines under the ground, in order to achieve the specified impedance value of less than 10 ?, was deemed ineffective in reducing the high-frequency impedance. This paper introduces a new earthing design that produces low impedance value at the high-frequency domain, without compromising the performance of low-frequency impedance. The performance of this new earthing design, as well as the existing design, are simulated for various soil resistivity values at varying frequency. The proposed concentrated earthing design is found to possess low tower footing resistance (TFR) value at both low and high-frequency. A good earthing design should have a fine balance between compact and radial electrodes under the ground.
Effect of purification process on the thermal conductivity and breakdown voltage of inhibited, isoparaffinic transformer oil used in electric train
Authors: Ali Mahmood , Deenesh N.K. , Kadir Ghazali , Hasnan Khalid , Nayan Nafarizal
Published: June 2021

Presence of water content or moisture promotes premature thermal aging which hampers the properties of inhibited, isoparaffinic transformer oil used in electric multiple unit (EMU) train. Unpurified aged oil with high water presence is collected from the traction transformer and contaminants is removed using Double-Stage Vacuum Insulation Oil Regeneration Filtration Machine to produce purified aged oil. New transformer oil is selected as a control sample. The objective of this study is to investigate the effect of oil purification process on the thermal conductivity and breakdown voltage of the oil samples. Thermal conductivity measurement was done from temperatures of 30°C to 70°C. Dielectric characteristics are shown by analyzing breakdown voltage. Unpurified oil shows an increment from 1.54% to 3.13% as compared to new oil in response to temperature variation whereas purified oil has the lowest thermal conductivity value. However, breakdown voltage of purified oil is higher than unpurified oil and slightly lower than new oil. From this, it can be inferred that presence of water gives positive impact towards thermal properties and vice versa to dielectric properties. A relationship between thermal conductivity, breakdown voltage and presence of water has been deduced at the end of the study.
PV array and inverter optimum sizing for grid-connected photovoltaic power plants using optimization design
Authors: Zidane T E K , Zali S M , Adzman M R , Tajuddin M F N , Durusu A
Published: June 2021

This paper aims to select the optimum inverter size for large-scale PV power plants grid-connected based on the optimum combination between PV array and inverter, among several possible combinations. Inverters used in this proposed methodology have high-efficiency conversion in the range of 98.5% which is largely used in real large-scale PV power plants to increase the financial benefits by injecting maximum energy into the grid. To investigate the PV array-inverter sizing ratio, many PV power plants rated power are considered. The proposed method is based on the modelling of several parts of the PV power plant taking into account many design variables and constraints. The objective function is the levelized cost of energy (LCOE) and the optimization is performed by a multi-verse algorithm. The optimization method results in an optimum inverter size that depends on the PV plant rated capacity by providing an optimum number of inverters required in the installation site. The optimum sizing ratio (Rs) between PV array and inverter were found equal to 0.928, 0.904, and 0.871 for 1 MW, 1.5 MW, and more than 2 MW, respectively, whereas the total power losses reached 8% of the total energy generation during the PV power plant operational lifetime.
Angle-Based Photovoltaic Curve Tracing using Boost Converter
Authors: Ayop R , Tan C W , Syed Nasir S N , Nordin N M , Mahmud M S A
Published: June 2021

A photovoltaic (PV) curve tracer is equipment that obtains the characteristic curve of the PV that can be used for PV modelling or performance analysis. Currently, the used of the switched-mode power supply in the PV curve tracer application is limited due to the voltage ripple problem. This paper provides the potential and limitation of designing the PV curve tracer using the boost converter. A new angle-based curve tracing algorithm is proposed to produce evenly distributed tracepoints on the PV curve. The PI controller is used to control the boost converter based on the input from the angle-based curve tracing algorithm. The PV curve tracer is simulated using MATLAB/Simulink. The results show that the proposed PV curve tracer is accurate and trace a significant portion of the PV curve.
Solar Radiation Estimation Using Discriminate Analysis Algorithm for The Output Voltage of Photovoltaic Module
Authors: Irwanto M , Ismail B. , Nisja I. , Irwan Y. M. , Alam H , Baharudin N H , Jufrizal  , Leow W Z , Ahmad S
Published: June 2021

A study of solar radiation in one area is very important to decide the area is suitable or not to be constructed the generation of photovoltaic (PV) system. The solar radiation can be recorded using the equipment of solar power meter or weather station. But it is due to the limitation of equipment, maybe a technical error occurs on the equipment, thus the equipment has a problem to record the data of solar radiation or one area has no equipment of solar radiation recording. An estimation method of solar radiation is needed to solve the problem. This paper presents an estimation of solar radiation using discriminate analysis algorithm (DAA) that it is applied to the output voltage of PV module. The data of daily measured solar radiation, maximum and minimum temperature are obtained from Chuping Weather Station through the web of world weather online for the year of 2019. The maximum and minimum temperature are as predictor variables in the DAA to obtain the daily estimated solar radiation. The result of daily estimated solar radiation is applied to the output voltage of PV module and compared to the output voltage of PV module applied by the daily measured solar radiation using the statistical analysis, they are root mean square error (RMSE) and error percentage. The results show that the estimated and measured solar radiation have RMSE of 0.257 and error percentage of 1.649%. They indicate that the DAA is acceptable to estimate the solar radiation.
Design and Implementation of an IoT-based River Water Salinity Monitoring System Using MSP432
Authors: Truong Tuyen Phong , Nguyen Duc Thanh , Huynh Thuc
Published: June 2021

The drought and salinity intrusion in the Mekong Delta in the years has become more and more serious, but in this region, the system automatically measures and collects water salinity data at either the river mouths or the canal has not been deployed and used widely due to the high investment cost. The goal of this study is to design a monitoring and data acquisition on river water salinity based on the IoT (Internet of Things) technology. The sensor nodes are designed by using the Texas Instruments MSP432 microcontrollers to read data from sensors such as water level, temperature, and salinity. This information is encapsulated and then send to a gateway via a LoRa network. The gateway uses the Raspberry Pi 3 B+ board allowing to receive the data from the sensor nodes and upload data to the cloud server through the Internet connection. A webpage is designed to offer everyone to observe measured parameters rapidly so that the people can take a proactive plan to take water for domestic use and production activities. An experiment to evaluate the performance of our proposed system was carried out in Soc Trang province, Mekong Delta, Vietnam with initial positive results.
Preliminary Studies on Circular and Square Loop Antenna Design for Partial Discharge Detection
Authors: Affendi N. A. M. , Amirruddin M.
Published: June 2021

The objective of this study was to design and compare the performance of geometrical shape circular loop antenna and square loop antenna towards partial discharge (PD) detection. PD is an early stage of fault occurs before major breakdown may due to electrical insulation failure, natural disaster and mis-operation. The electromagnetic (EM) signal radiated from PD event was measured and analyse over a range of frequency 300 MHz – 3 GHz. A circular and square loop antennas were modeled using CST Microwave Studio software based on the PD’s characteristics. The loop antenna parameters such as circumference, radius and end to end gap were varied accordingly to assess the effect of return loss and radiation pattern. The results revealed that the circular loop antenna had the greatest influence towards PD detection.
Simulation analysis of a 3.37 MW PV system using bifacial modules in desert environment
Authors: Samer Raed Abdullah Ba , Ismail Baharuddin Bin , Abdullah Ahmad Zaidi , Ali Izzulsali Md
Published: June 2021

This study is conducted to investigate the performance of bifacial solar PV with high albedo in desert regions. High amount of radiation falls on the Arabian Peninsula where there is an average amount of 2200 kWh/m 2 annually and needs to be utilize as much as possible to get higher amount of energy. A 3.37 MW system is simulated by PVsyst software using two different scenarios which the first is without an axis tracker while the other is with a dual axis tracker to track the sunlight from all directions. When the tracking system is not included the yearly energy production set to be 6684 MWh/year where the system is simulated at a fixed mounting at a single direction facing the south at an optimum tilt angle of 25?. On the other hand, when the tracking system is set to be dual trackers at a minimum tilt angle of 0? and maximum tilt angle of 80? vertically, and minimum azimuth angle of -120 and maximum azimuth angle of -120? horizontally. There annual energy production is set to be 8897 MWh which has a gain of 25% using bifacial solar module with tracking system which can add a value to the solar PV projects and decrease the levelized cost of energy (LCOE).
The Influenced of Different Magnetization Patterns on the Performance of the Semi-buried Permanent Magnet Synchronous Machine
Authors: Mohd-Shafri Syauqina Akmar , Sani Muhamad Haniff , Tiang Tow Leong , Ishak Dahaman , Ahmad Mohd Saufi , Leong Jenn Hwai , Tan Choo Jun , Ong Hui Lin
Published: June 2021

The performance of semi-buried permanent magnet synchronous machines (SBPMSMs) by the influence of two magnetization patterns are presented in this paper. These magnetization patterns include radial and parallel, which applied into 9-slot/8-pole (9s/8p) and 6-slot/4-pole (6s/4p) SBPMSMs. Hence, to evaluate the machines performance, AutoCAD and Opera2D finite element software are used to model and predict the electromagnetic characteristic performance of SBPMSMs. Two PM machines are optimized i.e. flux density distribution, phase back-EMF, and cogging torque by two magnetization patterns. The phase back-EMF of the machines are computed into harmonic components to investigate the total harmonic distortion (THDv
). It is found that the lowest THDv
for both 9s/8p and 6s/4p motors are in parallel magnetization (PaM), which are 8.66% and 3.98%, respectively. However, the lowest cogging torque for 9s/8p is radial magnetization (RaM), which is 0.0101 Nm and for 6s/4p is 0.1730 Nm with parallel magnetization pattern. By comparing the result of the optimum magnet pole arc for both motors, the 6s/4p motors show the minimum cogging torque and harmonic distortions are 0.16 Nm and 1.63% in PaM patterns. As a result, optimum motor performances among these two motors are 6s/4p PM motors with PaM pattern.
Maintenance Plan Based on TPM for Turbine Recovery Machinery
Authors: Lozada-Cepeda José Antonio , Lara-Calle rés , Buele Jorge
Published: June 2021

The maintenance and repair of the components of hydroelectric turbines require the use of specialized equipment. To keep these teams operational, it is proposed to design a master plan in order to develop a TPM philosophy for a vertical turning lathe. This project develops five of the twelve steps established by JIPM for the TPM implementation. This paper also provides the necessary documentation for 5S and autonomous maintenance applications. Also, some safety, health and environmental suggestions are provided. PM activities are chosen based on RCM techniques like CA and FMEA. And predictive maintenance activities are established following ISO 3655, 2006. All these activities including automotive maintenance ones are organized and scheduled. Finally, OEE rate is applied to the lathe to identify the principal losses on the machine. After applying this proposal there is an increase of 27.84% and 39.71% in availability and performance respectively. The OEE calculation has increased by 29.97%, thereby motivating readers to implement this methodology in other industries.
Fault Detection Analysis for Three Phase Induction Motor Drive System using Neural Network
Authors: Mohar N A , Che Mid E , Suboh S M , Baharudin N H , Ahamad N B , Rahman N A , Ruslan E , Hadi D A
Published: June 2021

One of the most important components of the industrial process is known to be the three-phase induction motor. This device, however, is prone to electrical and mechanical faults, which may cause a substantial component or financial losses. The fault analysis received growing attention due to a need to increase reliability and to decrease potential output loss due to machine breakdown. Thus, the purpose of this paper is to present a simple and reliable fault analysis based on the Neural Network (NN) is proposed. The NN method is a simpler approach without a diagnostic professional to review data and diagnose issues. Various fault disputes of induction motor are developed and analysed using the NN method. The main types of faults considered are over-voltage, under-voltage, and unbalanced voltage faults. The trained network is tested with simulated fault current and voltage data.
Arcing fault diagnosis using first peak arrival of EM radiation signal
Authors: Amirruddin Melaty , Adzman Mohd Rafi , Affendi Nur Adyani Mohd , Azmi Azralmukmin , Idris Muhd Hafizi , Halim Hana Abdull , Isa Muzamir , Halim Syahirah Abdul
Published: June 2021

The objective of this study was to diagnose the arcing fault signals based on the first peak of arrival method using antenna to assess its use as potential arcing fault detection in power system network. Square patch antenna and circle patch antenna were employed for detection on artificial arcing in real environment. First peak of arcing signal arrival was measured through an analysis over a range of time and amplitude signals detected. For accurate results, Discrete Wavelet Transform (DWT) denoising technique was applied to the arcing signals detected as denoising tools. Analysis of first peak of signal arrival time and amplitude were carried out using MATLAB software to measure the changes in signals detected caused by di different placements of antenna. The results revealed that the first peak of signal arrival time, amplitude, type of antenna used and placement of the antenna around arcing source point all reflect the signals measurement.
A Decade of Soft Computing Approaches in Power System Investment Planning
Authors: Yaakob S B , Rahman A S F , Mukhtar N M , Yaakob M N , Arbaiy N , Lin P-C
Published: June 2021

This paper opens up an issue regarding to power system investment planning. In order to obtain a sustainable electricity supply, the power outage should be minimized. Maintenance cost plays as an essential element in investment planning, therefore misdirect investment should be avoided. Since soft computing can solved this problem, this paper offers a review in solving investment planning problem through such approaches. The main objective of this paper is to examine the concept and findings by the researchers in power system investment planning problem. Besides, this paper will highlight the most relevant contributions and limitations that can be improve in the other research. Finally, this paper will be pointed out some trends in power system investment planning problem.
Comparative Study of Thermal Energy Harvesting on Agricultural Soils using Thermoelectric Generator (TEG)
Authors: Saharun I F , Saudin N , Mohamed M A , Jamel N , Mohamed H
Published: June 2021

Thermal energy harvesting system using a thermoelectric generator (TEG) can operate low voltage devices up to 5 V. The TEG will act as a small electric generator from the temperature difference obtained from two different conditions. Soil is an excellent source to get a more considerable temperature difference. The ground has a much lower temperature than the ambient as the solar radiation cannot penetrate deeply into the soil. Agricultural soil with a different type of plant has been chosen as the source in this study as the different soil composition will provide a different temperature gradient. The temperature gradient was measured from the surrounding and the soil. The highest energy harvested and generated were measured and compared between different types of agricultural soil. The results lead to a finding of a lot of other factors influencing the efficiency of the energy harvesting tools and the voltage generated from different types of soil. It shows that the hot surrounding with colder soil temperature gave a promising result.
Output Power Maximization of DFIG Wind Turbine using Linear MPC Technique
Authors: Suboh S M , Hassan M S , Baharudin N H , Ananda-Rao K , Ahamad N B , Che Mid E , Othman M , Sardi Junainah
Published: June 2021

Wind energy conversion systems have been attracting wide attention as a renewable energy source. To extract maximum energy from the wind turbine, an efficient controller plays an important role. The target of this paper is to develop a Linear Model Predictive Control (MPC) to maximize power production according to wind speed. Firstly, the DFIG wind turbine model was linearized at a specific operating point by using the Jacobian method. The MPC then was developed based on the linearized model where wind speed equal to 8 m/s is chosen as its operating area. The controller was tested to deal with different wind speed. A presence of a certain range of wind speed errors was included to evaluate the controller efficiency. Numerical simulation was done by using MATLAB software. The proposed controller has shown great performances when within its operating area but downgraded when moving away from its operating area. Imprecise wind speed measurement has shown a significant impact on the controller efficiency.
Classification of imbalanced data using support vector machine and rough set theory: A review
Authors: Ibrahim H , Anwar S A , Ahmad M I
Published: June 2021

The performance of machine learning classifier such as support vector machine (SVM) degraded by the nature and structural construct of real-world data which is in most cases are imbalanced. The accuracy and decision making typically biased towards majority class and this significantly affect the result of the classification of minority class. Nevertheless, dataset does not always comprise of significant attributes even with large number of points in certain class, but rather it could potentially lead to redundancy and irrelevant features. Rough set (RS) theory is a mathematical tool for tackling ambiguity and removing redundancy in the dataset. This can further help the classification system in improving its accuracy of the prediction for both majority and minority class. Commonly, RS theory was utilised as a preprocessing method to bring about the knowledge, association rules, or potential patterns in the data. The output of RS theory is a reduced set of attributes which contains same indiscernibility as the original dataset. Hence, the focus of this paper is a review of literature and findings on the classification strategy which employs SVM and RS as a combined system to solve the problem of imbalanced data.
Palmprint features matching based on KAZE feature detection
Authors: Khalid Noor Aldeen A. , Ahmad Muhammad Imran , Mandeel Thulfiqar H. , Isa Mohd Nazrin Md
Published: June 2021

Palmprint is very popular biometric recognition system that is able to guarantee high accuracy. It has attracted increasing amount of attention because palmprints are abundant of many characteristics, such as the principle lines, ridges, minute points and textures for the use of images with low resolution. In this paper we propose palmprint feature detection based on KAZE technique. Palmprint texture has many important points for discrimination process. Selecting the best number of point using KAZE is very important for classification process in order to avoid overlapping features in different class. The experimental work has been done using polyU palmprint database in order to evaluate the best number of features.
A Deep Feedforward Neural Network Model for Image Prediction
Authors: Lee C.C. , Rahiman M.H.F , Rahim R. A. , Saad F. S. A.
Published: June 2021

Deep learning is a sub-field of machine learning, which inspired by the structure of human brain where it is composed with a lot of neurons that each of them able to perform a simple operation and interact with each other to make a decision. In recent years, deep learning has grown exponentially and have brought revolutionary advances in computer vision-based applications such as image classification, object detection, simultaneous localisation and mapping (SLAM), action and activity recognition, age estimation as well as human pose estimation. Based on the literature review, deep learning techniques applied in the vision-based application such as Convolutional Neural Networks (CNNs), Restricted Boltzmann Machines (RBMs), Autoencoder and Sparse Coding mostly focused on solving the feature extraction and classification problems. However, these techniques do not apply to the image processing applications such as image fusion and image reconstruction that require a quantitative knowledge to solve some problems in such fields. The process of obtaining quantitative knowledge in image fusion and reconstruction is a regression problem. In this case, a deep feedforward neural network is applied to solve the regression problem due to its ability to map complicated nonlinear functions.
20 Mb/s Experimental Demonstration Using Modulated 460 nm Blue LED for Underwater Wireless Optical Communications (UOWC)
Authors: Seow Y. L. , Rashidi C. B. M. , Aljunid S. A. , Ali N. , Endut R.
Published: June 2021

This paper has demonstrated an experimental low power consumption underwater wireless optical communication (UWOC) system with 460-nm LZ1-00DB00 Blue LED and avalanche photodetector. With the LZ1-00DB00 Blue LED operating at a driving current of 1200 mA with an optical power of 5280 mW, UWOC link offering a data rate up to 20 Mb/s over a transmission range of 5 meters under an underwater channel link. The measured bit-error rate (BER) is 3 × 10-3
which pass well the forward error correction (FEC) threshold.
Ultra-wideband Antenna with Slotted Ground Structure for Wireless Application
Authors: Bakar H A , Rahim R A , Jack S P , Isa S R
Published: June 2021

This paper presents a software-based design of an ultra-wideband slot antenna that is applicable for wireless applications. Due to introduction of polygonal wide slot in the ground plane, the ultra-wideband has been achieved. The battery slot and rectangular shapes are implemented to improve S11, operating bandwidth range and radiation pattern of antenna. The optimal dimensions of the presented antenna are 45mm × 45mm × 1.565mm and is simulated on FR-4 substrate with relative permittivity of 4.3 and loss tangent of 0.025. The proposed antenna shows wide impedance bandwidth of 4.56GHz (104%) ranging0 from 2.08GHz to 6.64GHz that covers WLAN and WIMAX application.
Promising areas of insurance for farm animals
Authors: Zhichkin K , Nosov V , Zhichkina L , Nechushkin A , Pavlyukova A , Korobova L
Published: June 2021

The article considers proposals for improving the insurance of farm animals with state support. The aim of the study is to develop new programs for insurance of farm animals with state support, based on a decrease in productivity. The main goal in calculating insurance rates is related to the determination and coverage of the likely amount of damage attributable to each policyholder. The insurance scheme of climatic risks in dairy cattle breeding is proposed, taking into account the animals productivity. Based on scientific data on a decrease in milk yield at an air temperature of more than 30°C, it is proposed to compensate for the decrease in productivity during the high temperatures period. In the Samara region, the insurance premium will amount to 1707.8 rubles per head. The total amount of the insurance premium will be 75126.0 thousand rubles, and the amount of state support for this program - 37563.0 thousand rubles in year. Thus, animal insurance and its state support is a reliable tool for reimbursement of losses for agricultural producers in the risky events in the livestock industry.
Empowerment model of seed breeders in the supplying sustainable rice seeds in North Sumatra Province
Authors: Asaad M , Martial T , Novita D , Dharma S
Published: June 2021

Empowerment of rice seed breeders in North Sumatra Province aims to improve the ability of seed breeders to become independent and sustainable seed breeders. The study aims to determine the conditions of cultivation, postharvest, and marketing of rice seed breeder and to formulate appropriate models for empowering rice seed breeders. This type of research is descriptive qualitative analysed through research and development methods. The research was conducted in six rice production centre districts in North Sumatra. The results showed that the empowerment of breeder groups was not optimal. This condition is indicated by the dominance of one people in the breeder group as determinants of policy. In addition, most seed breeders are only willing and able to carry out breeding activities only up to the cultivation stage which produces Harvested Dry Grain, do not participate in post-harvest (drying, sorting and certification) and marketing activities. This is due to the lack of motivation of breeders, limited facilities, financial problems and the lack of knowledge and skills of farmers. Therefore, efforts are needed to empower seed breeders in a comprehensive manner, including cultivating motivation, training, partnership, and support from local governments and companies to facilitate breeders in marketing the seeds they produce.
The potency of mungbeans enhancement in Sambas Regency West Kalimantan
Authors: Dewi D O , Burhansyah R
Published: June 2021

Agricultural Development is very important as a motor of national economy. Local Resources need to be empowered to improve the welfare of the farming community. This empowerment impacts the problems and opportunities in the development of mungbeans in West Kalimantan. The Indonesian Ministry of Agriculture makes West Kalimantan Province as one of the priorities for the development of legumes and tuber Agro-industries. The development of legumes such as mungbeans is part of an effort to diversify food. This research was conducted in June to October 2017 in Sambas Regency, West Kalimantan. The methodology used is the PRA (Participatory Rural Appraisal) with 30 respondents farmers owners and traders. The results showed that Sambas Regency has the potency for enhancing mungbeans in West Kalimantan. This is supported by natural resources, land resources and farmer resources. From the results of financial analysis in 4 sub districts in Sambas Regency, it can be seen that the highest net income received by farmers in the Teluk Keramat District is IDR. 17,136,750, - with an R / C value of 3.49 and B / C ratio of 2.49.
Influencing factors of madura cattle farmers’ courage to face risks of breeding
Authors: Novanda R R , Khaliqi M
Published: June 2021

Traditional Madurese cattle farmers experience many difficulties in carrying out cattle breeding. Madurese cattle farmers do not have genetic data on the cows they raise, making it difficult for breeders to produce superior calves. Cattle breeding is often considered high risk because it is biologically susceptible to disease and death. In addition, the low selling price of local cattle breeds is not comparable to the care performed by farmers. So, it is crucial to analyse the factors that influence the ability of Madura cattle farmers to face the risk of breeding. This research was conducted in Pamengkasan Madura with 100 respondents. The selected respondents are Madura cattle farmers who do business in the Madura cattle breeding. Data analysis was carried out using ordinal regression analysis method. Based on the results of data processing, it was found that Self Confidence and Optimism had a significant effect on the ability of Madura cattle farmers to face risks. At a 10% confidence level, Self Confidence and Optimism has a significant impact on the power of Madura cattle farmers to face risks with a P-value of 0.087.
Analysis of willingness to pay organic vegetables in Medan
Authors: Marda N H B , Salmiah  , Ayu S F
Published: June 2021

A healthy lifestyle is now internationally institutionalized and requires a guarantee that agricultural products must globally standardized and requires an assurance that farming items must have food safety, high nutritional and eco-labelling attributes. These things maters become motivation for living a healthy lifestyle. The research objective was to determine factors affecting willingness to pay for organic vegetables in Medan City, by using logistic regression analysis which sourced from primary data. The results show that value of Willingness to Pay consumers for organic vegetables (in the modern market of Medan City is higher by 10.40% - 12.89% of the price offered. The highest percentage of WTP increase in organic vegetable product consumers was spinach and the lowest was mustard greens. Income and product price have a significant effect on willingness to pay for organic vegetables meanwhile education level, age, and number of family members do not have significantly effect.
Comparative profitability of small-scale rice and horticultural farming in South Konawe District of Southeast Sulawesi
Authors: Saediman H , Astuti R W , Alwi L O , Zani M , Mboe I S
Published: June 2021

Shortages in the national rice supply are attributable to several factors, one of which is crop shift from rice to other crops. This study aimed to find out the amount of net returns from rice farming and horticultural farming which could be one of the reasons for crop shifting. The respondents were former rice farmers who had left rice farming and now grown melon, watermelon, or chili. Data were analysed using cost and returns analysis and paired sample t-test. The results showed that the average net returns of rice farming per farm were IDR29,667,325/year, and the average net returns per hectare were IDR21,181,531/year. For horticultural farming, the average net returns were IDR49,309,679/farm/year or IDR122,172,194/ha/year. Net returns from horticultural production were significantly higher than that from rice production. Such a significant difference in the net returns might be one reason for the crop shifting from rice farming to horticultural farming. Horticultural production provides high income to the farmers and supports local economic growth, but abandoning rice fields in the long run may not be in line with the promotion of food security both at the local and national level.
The influence of the pandemic COVID-19 on the food supply chain management
Authors: Nesterenko N , Vetrova M , Ivanova D
Published: June 2021

Food supply chain management is a main object of the food security. How to form an effective food supply chain in pandemic conditions is the one of the most important questions nowadays. The agro-food system is becoming not only a tool for solving many economic and social problems that arise in the context of a pandemic, but itself is experiencing a serious impact from consumers, business, and the state. The pandemic negatively affected the agri-food system of different countries. Among the main problems, we will single out the reduction in demand for fresh food, disruptions in the supply of incoming resources, both for the production of products and for their sales, a shortage of labour, especially seasonal. The article examines the impact of the COVID-19 pandemic on the food supply chains in Russia. Using the example of supply chains in St. Petersburg, we show that the food supply chain tends to be shorter because of the consumer’s willingness to buy food direct from farmers avoiding risks to be infected with COVID-19. Another change in food supply chain is the increasing role of government in regulation of food security in region.
Implementation of rice farming insurance to support food security and the willingness to pay (case study in Cinta Damai Village, Percut Sei Tuan Subdistrict, Deli Serdang District)
Authors: Pane T C , Supriyono Y , Novita D
Published: June 2021

In order to increase food production, the government has made an innovation to protect farmers from the crop failure or damage risk by using the Rice Farming Insurance (AUTP) program. Agricultural insurance has been proven in many countries to successfully protect farmers from various farming risks. The presence of agricultural insurance is expected to play an important role in supporting economic activities in the agricultural sector, but unfortunately, this program has failed to run in Cinta Damai Village, Percut Sei Tuan Subdistrict, Deli Serdang District because of the farmers’ objections to paying the insurance premium. The purposes of this study were to see the actual implementation of the AUTP program and calculate the farmers’ willingness to pay (WTP) for the AUTP premium. The results of the interview were analysed and explained by the Statistical Description and then the farmers’ willingness to pay (WTP) for the AUTP premium was calculated. The results showed that the implementation of the AUTP program in Cinta Damai Village had gone well and smoothly, from the socialization to the claim settlement processes were almost completely according to the AUTP implementation guideline. The farmers’ expected average WTP (EWTP) value was 71,011 IDR/ha/growing season or 142,022 IDR/ha/year.