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28,451 Article Results

Risk of Transient Stability Using Rotor Trajectory Index as Severity Function

10.11591/ijeecs.v6.i3.pp591-601
Elmotaz Billa Elghali , Marayati Marsadek , Agileswari K. Ramasamy
This paper presents a new approach to determine the risk of transient stability. It describes the implementation of rotor trajectory index (RTI) to assess the severity of power systems when it is subjected to a three-phase fault. The (RTI) is proposed as an index used to represent severity of transient instability. Risk of transient stability for three-phase fault is calculated using a well-known risk formula. Risk of transient stability provides a quantitative measure to evaluate the potential loss of synchronism of a generator that takes into account the probability and consequences. RTI index is calculated based on the machines rotor angles obtained at each step of a time domain simulation. RTI is proposed as an index to show the severity of the three-phase fault towards transient stability since it allows a fast and accurate measurement of the degree of stability of the system facing a fault. The proposed technique is implemented on the IEEE 39-bus system.
Volume: 6
Issue: 3
Page: 591-601
Publish at: 2017-06-01

A Survey on Security Aspects of Server Virtualization in Cloud Computing

10.11591/ijece.v7i3.pp1326-1336
O Sri Nagesh , Tapas Kumar , Venkateswara Rao Vedula
Significant exploitation and utilization of cloud computing in industry is come with and in the identical time vulnerable by unease regarding protection of data hold by cloud computing providers. One of the penalties of moving data processing and storage off business site is that organizations have fewer controls over their infrastructure. seeing that, cloud service (CS) providers must hope that the CS provider is capable to protect their data and infrastructure from both exterior and domestic attacks. Presently however, such hope can only rely on organizational procedures stated by the CS provider and cannot be remotely verified and validated by an external party. The central distinction between cloud computing and conventional enterprise internal Information Technology services is that the proprietor and the consumer of cloud Information Technology infrastructures are separated in cloud. This transform requires a safety responsibility severance in cloud computing. Cloud service providers (CSP) should safe the services they propose and cannot surpass the customers’ authorities. Virtualization is a buildup utterance in the Information Technology world. With the assure to reduce the ever mounting infrastructure inside data centers connected to other important apprehensions such as ease of use and scalability, virtualization technology has been in advance recognition not only with IT experts yet also among administrators and executives as well. The progressively more growing rate of the approval of this technology has exposed these systems to new protection concerns which in recent history have been unnoticed or merely overlooked. This paper presents an in depth state of art gaze at  present most old server virtualization explanations, as well as a writing study on different security matters found inside this virtualization technology. These problems can be practical to all the existing virtualization technologies accessible with no spotlight on a specific answer. Nevertheless, we do susceptibility investigation of two of the mainstream recognized virtualization answers: VMware ESX and Xen. to conclude, we illustrate some clarifications on how to progress the security of online banking and electronic commerce, using virtualization.
Volume: 7
Issue: 3
Page: 1326-1336
Publish at: 2017-06-01

VLSI Design of a Fast Pipelined 8x8 Discrete Cosine Transform

10.11591/ijece.v7i3.pp1430-1435
Nurulnajah Mohd Zabidi , Ab Al-Hadi Ab Rahman
This paper presents a Very Large Scale Integrated (VLSI) design and implementation of a fixed-point 8x8 multiplierless Discrete Cosine Transform (DCT) using the ISO/IEC 23002-2 algorithm. The standard DCT algorithm, which is mainly used in image and video compression technology, consists of only adders, subtractors, and shifters, therefore making it efficient for hardware implementation. The VLSI implementation of the algorithm given in this paper further enhances the performance of the transform unit. Furthermore, circuit pipelining has been applied to the base design of the DCT, which significantly improves the performance by reducing the longest path in the non-pipeline design. The DCT has been implemented using semi-custom VLSI design methodology using the TSMC 0.13um process technology. Results show that our DCT designs can run up to around 1.7 Giga pixels/s, which is well above the timing required for real-time ultra-high definition 8K video.
Volume: 7
Issue: 3
Page: 1430-1435
Publish at: 2017-06-01

The Effect of Different Dielectric Materials in Designing High-Performance Metal-Insulator-Metal (MIM) Capacitors

10.11591/ijece.v7i3.pp1554-1561
M. A. Zulkifeli , S. N. Sabki , S. Taking , N. A. Azmi , S. S. Jamuar
A Metal-Insulator-Metal (MIM) capacitor with high capacitance, high breakdown voltage, and low leakage current is aspired so that the device can be applied in many electronic applications. The most significant factors that affect the MIM capacitor’s performance is the design and the dielectric materials used. In this study, MIM capacitors are simulated using different dielectric materials and different number of dielectric layers from two layers up to seven layers.  The effect of the different dielectric constants (k) to the performance of the MIM capacitors is also studied, whereas this work investigates the effect of using low-k and high-k dielectric materials. The dielectric materials used in this study with high-k are Al2O3 and HfO2, while the low-k dielectric materials are SiO2 and Si3N4. The results demonstrate that the dielectric materials with high-k produce the highest capacitance. Results also show that metal-Al2O3 interfaces increase the performance of the MIM capacitors. By increasing the number of dielectric layers to seven stacks, the capacitance and breakdown voltage reach its highest value at 0.39 nF and 240 V, respectively.
Volume: 7
Issue: 3
Page: 1554-1561
Publish at: 2017-06-01

Effects of Switching Frequency Modulation on Input Power Quality of Boost Power Factor Correction Converter

10.11591/ijpeds.v8.i2.pp882-899
Deniss Stepins , Jin Huang
Switching frequency modulation (SFM) as spread-spectrum technique has been used for electromagnetic interference reduction in switching power converters. In this paper, a switching-frequency-modulated boost power factor correction (PFC) converter operating in continuous conduction mode is analysed in detail in terms of its input power quality. Initially, the effect of SFM on the input current total harmonic distortion, power factor and low-frequency harmonics of the PFC converter are studied by using computer simulations. Some advices on choosing parameters of SFM are given. Then the theoretical results are verified experimentally. It is shown that, from a power quality point of view, SFM can be harmful (it can significantly worsen the power quality of the PFC converter) or almost harmless. The results depend on how properly the modulation parameters are selected.
Volume: 8
Issue: 2
Page: 882-899
Publish at: 2017-06-01

A Constant Switching Frequency DTC for PMSM Using Low Switching Losses SVM–An Experimental Result

10.11591/ijpeds.v8.i2.pp558-583
K. Chikh , A. Saad , M. Khafallah , D. Yousfi , F.Z. Tahiri , M. Hasoun
A Constant Switching Frequency Direct Torque Control (CSF-DTC) with low switching losses Space Vector modulation (SVM) for Permanent Magnet Synchronous Motor (PMSM) drive is proposed in this work. The CSF-DTC combines Field Oriented Control (FOC) and basic DTC advantages. Indeed, the proposed control strategy improves the basic DTC performances, which features low flux and torque ripples as well as a fixed switching frequency. The improved DTC ensures also a fast and robust flux and torque responses by using Integral and Proportional (IP) controllers which guaranteed a good disturbance rejection.On the other hand, a symmetrical SVM technique with low switching losses in the PWM inverter is used in order to generate the desired stator voltage vector needed to control the stator flux and the motor torque. Simulation and experimental results are presentedin this paper.These results demonstrate well the performance of the basic and proposed DTC and they show the effectiveness of the constant switching frequency direct torque control.
Volume: 8
Issue: 2
Page: 558-583
Publish at: 2017-06-01

Cascaded Symmetric Multilevel Inverter with Reduced Number of Controlled Switches

10.11591/ijpeds.v8.i2.pp795-803
Tila Muhammad , Adnan Umar Khan , Hanif Jan , Muhammad Yasir Usman , Junaid Javed , Arsalan Aslam
Multilevel inverters have become popular among high power converters for the past few years due to their high quality output waveform and low total harmonic distortions (THD). In addition, the filter size also reduces significantly to achieve a pure sine wave output. Cascaded H-Bridge topology has been recognized as the most promising among various classical topologies for multi-level inverters on the basis of its modular form and ease of design, troubleshooting, packaging and high power capabilities. However, a large number of switches are required in cascaded H-Bridge multilevel inverter that leads to larger system losses and an increase in cost. In this paper the modified cascaded topology is proposed to reduce the number of controlled switches without affecting the resolution of output waveform or the number of voltage levels. We achieved this by replacing some of the high cost controlled transistor switches with diodes, in the cascaded H-Bridges. Furthermore, equal voltage source sharing is also possible by using the proposed topology. Hence the proposed inverter is a type of cascaded multilevel inverter with reduced switches, better modular structure, low cost and high efficiency. The inverter design is validated using simulations and tested on hardware prototype.
Volume: 8
Issue: 2
Page: 795-803
Publish at: 2017-06-01

Shape Based Image Retrieval using Lower Order Zernike Moments

10.11591/ijece.v7i3.pp1651-1660
G. Sucharitha , Ranjan K. Senapati
Shape is one of the significant features of Content Based Image Retrieval (CBIR). This paper proposes a strong and successful shape feature, which is based on a set of orthogonal complex moments of images known as Zernike moments. For shape classification Zernike moment (ZM) is the dominant solution. The radial polynomial of Zernike moment produces the number of concentric circles based on the order. As the order increases number of circles will increases, due to this the local information of an image will be ignored. In this paper, we introduced a novel method for radial polynomial where local information of an image given importance. We succeeded to extract the local features and shape features at very a low order of polynomial compared to the state of traditional ZM.The proposed method gives an advantage of a lower order, less complex, and lower dimension feature vector.For more similar images we find that simple  Euclidian distance approximately zero. Proposed method tested on a MPEG-7 CE-1 shape database, Coil-100 databases. Experiments demonstrated that it is outperforming in identifying the shape of an object in the image  and reduced the retrieving time and complexity of calculations.
Volume: 7
Issue: 3
Page: 1651-1660
Publish at: 2017-06-01

Investigating Agile Adaptation for Project Development

10.11591/ijece.v7i3.pp1278-1285
Rajesh H. Kulkarni , P. Padmanabham , Manasi Harshe , K.K. Baseer , Pallavi Patil
Agile methodologies adaptation in software companies is an accepted norm.Rapid application development and efficient deliverables being the premise. The changing business needs, cost effectiveness and timely delivery are catered to by agile methods. Different software development models are in the literature and also are being used by the industry. Few companies have adopted agile, few are gearing up for and few are in transition. We investigated agile presence in a software company.Project management is an evolving art with innovative methods being added up.The aim of this paper is to tease about project management challenges, agile, agile transition in companies and a comparison of conventional software engineering practices with agile process model.This paper takes stock of the current status of quality in software projects and to add on quality process improvement strategies. The results presented here are after a qualitative interview study with one cross function team using streamline development framework in agile development.
Volume: 7
Issue: 3
Page: 1278-1285
Publish at: 2017-06-01

Different Control Schemes for Sensor Less Vector Control of Induction Motor

10.11591/ijpeds.v8.i2.pp712-721
Srinivas Gangishetti , Tarakalyani Sandipamu
This paper deals with the design of different control schemes for sensorless vector control of induction motor.Induction motor is most widely used A.C. Motor but  the major draw back is flux and torque cannot be controlled individually.This can be obtained by implementing  sensorless vector control methods.The control strategy of induction motor  is by different controllers like conventional control methods and artificial intelligence control methods.The conventional control methods are sensitive to parameter changes and will not be accurate. This paper proposes to design a controller to over come the above draw backs by using intelligent control techniques like fuzzy logic, artificial neutral networks (ANN) and genetic algorithm (GA).The above conventional control methods are compared with intelligent control techniques. The simulation studies are carried out using Matlab/Simulink and the wave forms for speed, torque and voltage components for various controlles are plotted. Numerical analysis for speed and torque components considering parameters like peakover shoot and peak time are presented.
Volume: 8
Issue: 2
Page: 712-721
Publish at: 2017-06-01

A novel integrated dual microneedle-microfluidic impedance flow cytometry for cells detection in suspensions

10.11591/ijece.v7i3.pp1513-1521
Muhammad Asraf Mansor , Masaru Takeuchi , Masahiro Nakajima , Yasuhisa Hasegawa , Mohd Ridzuan Ahmad
In this study, a new, simple and cost-effective impedance detection of yeast cell concentration by using a novel integrated dual microneedle-microfluidic impedance flow cytometry was introduced. The reported method for impedance flow cytometry detection utilizes embedded electrode and probe in the microfluidic device to perform measurement of electrical impedance when a presence of cells at sensing area. Nonetheless, this method requires costly and complicatedly fabrication process of electrode. Furthermore, to reuse the fabricated electrode, it also requires intensive and tedious cleaning process. Due to that, a dual microneedle integrated at the half height of the microchannel for cell detection as well as for electrical measurement was demonstrated. A commercial available Tungsten needle was utilized as a dual microneedle. The microneedle was easy to be removed from the disposable PDMS microchannel and can be reused with the simple cleaning process, such as washed by using ultrasonic cleaning. Although this device was low cost, it preserves the core functionality of the sensor, which is capable of detecting the passing cells at sensing area. Therefore, this device is suitable for low cost medical and food safety screening and testing process in developing countries.
Volume: 7
Issue: 3
Page: 1513-1521
Publish at: 2017-06-01

Impact of Higher Order Adaptive Filtering for Stereo System Audio Signal

10.11591/ijeecs.v6.i3.pp623-627
A.A Amin , M. S. Islam , M. A. Masud , M. N. H. Khan
In present stereo audio system is a most popular audio system for different purposes. Now a day’s stereo system is commonly used in communication and other purposes. Moreover Normalized Least Mean Square (NLMS) based adaptive filtering is an effective filtering process in case of communication and other applications. However adaptive filtering is an adaptive filter process to cancel out the noise from audio signal successfully. Hence the main objective of this paper is to design a NLMS adaptive filter which cancels out the noise from a noisy wave format stereo audio file. Moreover by varying the order of the adaptive filter (such as 8th, 16th, 32th and 64th), the performance of the NMLS adaptive filtered signal with respect to reference and noisy stereo audio signal are analyzed as well.
Volume: 6
Issue: 3
Page: 623-627
Publish at: 2017-06-01

Analysis and Impact of D-STATCOM, Static Var Compensator, Fuzzy Based SVC Controller on the Stability of a Wind Farm

10.11591/ijpeds.v8.i2.pp935-944
Kaoutar Rabyi , Hassane Mahmoudi
In recent years, applications of facts systems have been developed for the compensation of active and reactive power. Facts systems are electronics devices that are connected to the wind farm. This paper presents the impacts of some of these devices on the stability of a wind farm, especially D-STATCOM, Static Var Compensator and Fuzzy SVC controller. First, a presentation of D-STATCOM, SVC, then fuzzy logic controller. In simulation study, the D-STATCOM ensures the stability of the voltage and current at the point of connection with the electrical grid. Finally, Comparing the SVC to the F-SVC simulations, we notice that the F-SVC is more performed than SVC for the compensation of the active and reactive power.
Volume: 8
Issue: 2
Page: 935-944
Publish at: 2017-06-01

Dynamic Modeling and Simulation of Short-Duration Over-excitation Phenomenon in Hysteresis Motor

10.11591/ijpeds.v8.i2.pp623-638
Sayyed Hossein Edjtahed , Amir Hossein Pir Zadeh , Abolfazl Halavaei Niasar
The hysteresis motor is a well-known synchronous motor that is used in special small power, high speed applications. Dynamic modeling and analysis of this motor is more complicated than permanent magnet synchronous motors (PMSMs) or induction motors (IMs) due to nonlinear behavior of rotor magnetic material. Short over-excitation is a unique phenomenon that only occurs in hysteresis motor in which the terminal voltage increase at synchronous speed for a short duration, and then continuously is decrease to initial value. Therefore, the input current is reduced, this leads to more power factor and efficiency enhancement. Till now, there isn’t any analytic dynamic model of this phenomenon. In this paper, based on a novel dynamic model of hysteresis motor, the over-excitation phenomenon is investigated and transient performance of the motor during over-excitation is simulated via Simulink.
Volume: 8
Issue: 2
Page: 623-638
Publish at: 2017-06-01

Carrier Shifting Algorithms for the Mitigation of Circulating Current in Diode Clamped MLI fed Induction Motor Drive

10.11591/ijpeds.v8.i2.pp844-852
C. Santhakumar , R. Shivakumar , C. Bharatiraja , P. Sanjeevikumar
Reduction of circulating current is one of the major considerations in inverter fed electrical drives. Diode clamped MLI enables higher output current per phase, thereby rating of the drive gets increased effectively. Various methods of triggering in the inverter legs creates better voltage profile and leads to the enabling of circulating current in the drive system.  The induced circulating current flows through the apparatus neutral (N) and supply ground (G) is caused by the existence of parasitic capacitance. This circulating current may cause potential danger especially when parasitic capacitance poses large. In the past, different modulation techniques and conversion topologies have been introduced to minimize the flow of circulating current. However, these techniques lead to complexity, high cost, low voltage profile and efficiency due to lower modulation parameters. This paper proposes PS, POD, PD carrier shifting PWM algorithms for diode clamped MLI to tumbling the circulating current within the each phase of inverter legs. The performances of proposed algorithm, in terms of circulating current, THD, losses and efficiencies are analyzed theoreticallyand are validated via simulation and experimental results.
Volume: 8
Issue: 2
Page: 844-852
Publish at: 2017-06-01
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