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28,812 Article Results

Quality of Service based Task Scheduling Algorithms in Cloud Computing

10.11591/.v7i2.pp1088-1095
Sirisha Potluri , Katta Subba Rao
In cloud computing resources are considered as services hence utilization of the resources in an efficient way is done by using task scheduling and load balancing. Quality of service is an important factor to measure the trustiness of the cloud. Using quality of service in task scheduling will address the problems of security in cloud computing. This paper studied quality of service based task scheduling algorithms and the parameters used for scheduling. By comparing the results the efficiency of the algorithm is measured and limitations are given. We can improve the efficiency of the quality of service based task scheduling algorithms by considering these factors arriving time of the task, time taken by the task to execute on the resource and the cost in use for  the communication.
Volume: 7
Issue: 2
Page: 1088-1095
Publish at: 2017-04-01

Performance of Non-Uniform Duty-Cycled ContikiMAC in Wireless Sensor Networks

10.11591/.v7i2.pp942-949
Nur Rabiul Liyana Mohamed , Ansar Jamil , Lukman Hanif Audah Audah , Jiwa Abdullah , Rozlan Alias
Wireless Sensor Network (WSN) is a promising technology in Internet of Things (IoTs) because it can be implemented in many applications. However, a main drawback of WSN is it has limited energy because each sensor node is powered using batteries. Therefore, duty-cycle mechanisms are introduced to reduce power consumption of the sensor nodes by ensuring the sensor nodes in the sleep mode almost of the time in order to prolong the network lifetime. One of the de-facto standard of duty-cycle mechanism in WSN is ContikiMAC, which is the default duty-cycle mechanism in Contiki OS. ContikiMAC ensures nodes can participate in network communication yet keep it in sleep mode for roughly 99\% of the time. However, it is found that the ContikiMAC does not perform well in dynamic network conditions. In a bursty network, ContikiMAC provides a poor performance in term of packet delivery ratio, which is caused by congestion. One possible solution is ContikiMAC should increase its duty-cycle rate in order to support the bursty traffic. This solution creates a non-uniform duty-cycle rates among the sensor nodes in the network. This work aims to investigate the effect of non-uniform duty-cycle rates on the performance on ContikiMAC. Cooja simulator is selected as the simulation tool. Three different simulation scenarios are considered depending on the Clear Channel Assessment Rate (CCR) configurations: a low uniform CCR value (Low-CCR), a high uniform CCR value (High-CCR) and non-uniform CCR values (Non-uniform-CCR). The simulation results show that the Low-CCR scenario provides the worst performance of PDR. On the other hand, the High-CCR scenario provides the best performance of PDR. The Non-uniform-CCR provides PDR in between of Low-CCR and High-CCR.
Volume: 7
Issue: 2
Page: 942-949
Publish at: 2017-04-01

Game-Theoretic Channel Allocation in Cognitive Radio Networks

10.11591/.v7i2.pp986-991
Sangsoon Lim
Cognitive radio networks provide dynamic spectrum access techniques to support the increase in spectrum demand. In particular, the spectrum sharing among primary and secondary users can improve spectrum utilization in unused spectrum by primary users. In this paper, we propose a novel game theoretic channel allocation framework to maximize channel utilization in cognitive radio networks. We degisn the utility function based on the co-channel interference among primary and secondary users. In addition, we embed the property of the adjacent channel intererence to consider real wireless environment. The results show that the utility function converges quickly to Nash equilibrium and achieves channel gain by up to 25 dB compared to initial assignment.
Volume: 7
Issue: 2
Page: 986-991
Publish at: 2017-04-01

Improved Timing Estimation Using Iterative Normalization Technique for OFDM Systems

10.11591/.v7i2.pp905-911
Suyoto Suyoto , Iskandar Iskandar , Sugihartono Sugihartono , Adit Kurniawan
Conventional timing estimation schemes based on autocorrelation experience performance degradation in the multipath channel environment with high delay spread. To overcome this problem, we proposed an improvement of the timing estimation for the OFDM system based on statistical change of symmetrical correlator. The new method uses iterative normalization technique to the correlator output before the detection based on statistical change of symmetric correlator is applied. Thus, it increases the detection probability and achieves better performance than previously published methods in the multipath environment. Computer simulation shows that our method is very robust in the fading multipath channel
Volume: 7
Issue: 2
Page: 905-911
Publish at: 2017-04-01

Hybrid Low Complex near Optimal Detector for Spatial Modulation

10.11591/.v7i2.pp818-822
P. Rajani Kumari , K. Chenna Kesava Reddy , K.S. Ramesh
In our previous work maximum throughput in multi stream MIMO is analyzed by overcoming the inter antenna interference. To mitigate the Inter antenna interference spatial modulation can be used. Spatial Modulation(SM) aided MIMO systems are the emerging MIMO systems which are low complex and energy efficient. These systems additionally use spatial dimensions for transmitting information. In this paper a low complex detector based on matched filter is proposed for spatial modulation to achieve near maximum likelihood performance while avoiding exhaustive ML search since MF based detector exhibits a considerable reduced complexity since activated transmitting antenna and modulated amplitude phase modulation constellation are estimated separately. Simulation results show the performance of the proposed method with optimal ML detector, MRC and conventional matched filter methods.
Volume: 7
Issue: 2
Page: 818-822
Publish at: 2017-04-01

Focusing Properties of a Modified Retarding Structure for Linear Electron Accelerators

10.11591/.v7i2.pp741-747
Vladimir Kuz'mich Shilov , Aleksandr Nikolaevich Filatov , Aleksandr Evgen'evich Novozhilov
When using accelerators in industry and medicine, important are the dimensions of the device used, especially the radial ones. In the linear electron accelerators based on a biperiodic retarding structure, which operates in the standing wave mode, there is a possibility to provide focusing of the accelerated particles with the help of high-frequency fields without the use of external focusing elements. In the accelerating cell, due to the presence of the far protruding drift sleeves, the electric field lines become strongly curved, which leads to the appearance in the regions adjacent to these sleeves of a substantial in magnitude radial component of the electric field. The particles entering the accelerating gap experience the action of a force directed toward the axis of the system, and at the exit, of a force directed away from the axis. Under certain conditions, alternation of the focusing and defocusing fields can lead to a general focusing effect. In the paper we study the focusing properties of a modified biperiodic structure with standing wave. The main attention is paid to the possibility of using the focusing properties of the electromagnetic accelerating field for guiding the electron beam through the aperture of the accelerating system, which will lead to a significant reduction in the accelerator sizes. The proposed method can be applied in the calculation and design of linear electron accelerators.
Volume: 7
Issue: 2
Page: 741-747
Publish at: 2017-04-01

Voltage Compensation In Wind Power System Using STATCOM Controlled By Soft Computing Techniques

10.11591/.v7i2.pp667-680
Bineeta Mukhopadhyay , Rajib Kumar Mandal , Girish Kumar Choudhary
When severe voltage sags occur in weak power systems associated with grid-connected wind farms employing doubly fed induction generators, voltage instability occurs which may lead to forced disconnection of wind turbine. Shunt flexible AC transmission system devices like static synchronous compensator (STATCOM) may be harnessed to provide voltage support by dynamic injection of reactive power. In this work, the STATCOM provided voltage compensation at the point of common coupling in five test cases, namely, simultaneous occurrence of step change (drop) in wind speed and dip in grid voltage, single line to ground, line to line, double line to ground faults and sudden increment in load by more than a thousand times. Three techniques were employed to control the STATCOM, namely, fuzzy logic, particle swarm optimization and a combination of both. A performance comparison was made among the three soft computing techniques used to control the STATCOM on the basis of the amount of voltage compensation offered at the point of common coupling. The simulations were done with the help of SimPowerSystems available with MATLAB / SIMULINK and the results validated that the STATCOM controlled by all the three techniques offered voltage compensation in all the cases considered.
Volume: 7
Issue: 2
Page: 667-680
Publish at: 2017-04-01

An Improved Integrated Hash and Attributed based Encryption Model on High Dimensional Data in Cloud Environment

10.11591/.v7i2.pp950-960
Satheesh K S V A Kavuri , Gangadhara Rao Kancherla , Basaveswararao Bobba
Cloud computing is a distributed architecture where user can store their private, public or any application software components on it. Many cloud based privacy protection solutions have been implemented, however most of them only focus on limited data resources and storage format. Data confidentiality and inefficient data access methods are the major issues which block the cloud users to store their high dimensional data. With more and more cloud based applications are being available and stored on various cloud servers, a novel multi-user based privacy protection mechanism need to design and develop to improve the privacy protection on high dimensional data. In this paper, a novel integrity algorithm with attribute based encryption model was implemented to ensure confidentiality for high dimensional data security on cloud storage. The main objective of this model is to store, transmit and retrieve the high dimensional cloud data with low computational time and high security. Experimental results show that the proposed model has high data scalability, less computational time and low memory usage compared to traditional cloud based privacy protection models.
Volume: 7
Issue: 2
Page: 950-960
Publish at: 2017-04-01

Compressed Sensing Speech Signal Enhancement Research

10.11591/ijeecs.v6.i1.pp26-35
Kuangfeng Ning , Guojun Qin
The proposed Compressive sensing method is a new alternative method, it is used to eliminate noise from the input signal, and the quality of the speech signal is enhanced with fewer samples, thus it is required for the reconstruction than needed in some of the methods like Nyquist sampling theorem. The basic idea is that the speech signals are sparse in nature, and most of the noise signals are non-sparse in nature, and Compressive Sensing(CS) eliminates the non-sparse components and it reconstructs only the sparse components of the input signal. Experimental results prove that the average segmental SNR (signal to noise ratio) and PESQ (perceptual evaluation of speech quality) scores are better in the compressed domain．
Volume: 6
Issue: 1
Page: 26-35
Publish at: 2017-04-01

Parallel Genetic Algorithms for University Scheduling Problem

10.11591/.v7i2.pp1096-1102
Artan Berisha , Eliot Bytyçi , Ardeshir Tershnjaku
University scheduling timetabling problem, falls into NP hard problems. Re-searchers have tried with many techniques to find the most suitable and fastest way for solving the problem. With the emergence of multi-core systems, the parallel implementation was considered for finding the solution. Our approaches attempt to combine several techniques in two algorithms: coarse grained algorithm and multi thread tournament algorithm. The results obtained from two algorithms are compared, using an algorithm evaluation function. Considering execution time, the coarse grained algorithm performed twice better than the multi thread algorithm.
Volume: 7
Issue: 2
Page: 1096-1102
Publish at: 2017-04-01

Image Processing for Rapidly Eye Detection based on Robust Haar Sliding Window

10.11591/.v7i2.pp823-830
Fitri Utaminingrum , Renaldi Primaswara Praetya , Yuita Arum Sari
Object Detection using Haar Cascade Clasifier widely applied in several devices and applications as a medium of interaction between human and computer such as a tool control that utilizes the detection of eye movements. Obviously speed and precision in the detection process such as eyes, has an effect if implemented on a device. If the eye could not detect accurately, controlling device systems could reach bad detection as well. The proposed method can be used as an approach to detect the eye region of eye based on haar classifier method by means of modifying the direction of sliding window. In which, it was initially placed in the middle position of image on facial area by assuming the location of eyes area in the central region of the image. While the window region of conventional haar cascade scan the whole of image start from the left top corner. From the experiment by using our proposed method, it can speed up the the computation time and improve accuracy significantly reach to 92,4%.
Volume: 7
Issue: 2
Page: 823-830
Publish at: 2017-04-01

Exploring the Design Space of HEVC Inverse Transforms with Dataflow Programming

10.11591/ijeecs.v6.i1.pp104-109
Khoo Zhi Yion , Ab Al-Hadi Ab Rahman
This paper presents the design space exploration of the hardware-based inverse fixed-point integer transform for High Efficiency Video Coding (HEVC). The designs are specified at high-level using CAL dataflow language and automatically synthesized to HDL for FPGA implementation. Several parallel design alternatives are proposed with trade-off between performance and resource. The HEVC transform consists of several independent components from 4x4 to 32x32 discrete cosine transform and 4x4 discrete sine transform. This work explores the strategies to efficiently compute the transforms by applying data parallelism on the different components. Results show that an intermediate version of parallelism, whereby the 4x4 and 8x8 are merged together, and the 16x16 and 32x32 merged together gives the best trade-off between performance and resource. The results presented in this work also give an insight on how the HEVC transform can be designed efficiently in parallel for hardware implementation.
Volume: 6
Issue: 1
Page: 104-109
Publish at: 2017-04-01

DARE Algorithm: A New Security Protocol by Integration of Different Cryptographic Techniques

10.11591/.v7i2.pp1032-1041
John Mark Espalmado , Edwin Arboleda
Exchange of information between computer networks requires a secure communications channel to prevent and monitor unauthorized access, modification and denial of the computer network. To address this growing problem, security experts sought ways to advance the integrity of data transmission. Security Attacks compromises the security and hence hybrid cryptographic algorithms have been proposed to achieve safe service in the proper manner, such as user authentication and data confidentiality. Data security and authenticity are achieved using these algorithms. Moreover, to improve the strength and cover each algorithm’s weaknesses, a new security algorithm can be designed using the combination of different cryptographic techniques. This design uses Digital Signature Algorithm (DSA) for authentic key generation, Data Encryption Standard (DES) for key scheduling, and Advanced Encryption Standard (AES) and Rivest–Schamir–Adleman Algorithm (RSA) in encrypting data. This new security algorithm has been proposed for improved security and integrity by integration of these cryptographic techniques.
Volume: 7
Issue: 2
Page: 1032-1041
Publish at: 2017-04-01

Radiation Pattern Performance of Unequally Linear Arrays with Parasitic Element

10.11591/ijeecs.v6.i1.pp110-115
Noor Ainniesafina Zainal , Muhammad Ramlee Kamarudin , Yoshihide Yamada , Norhudah Seman
For next generation of 5G mobile base station antennas, multibeam, multifrequency and low sidelobe characteristics requested. Simplify the feeding network will contribute a low feeder loss and frequency dependent. From the previous research by the author, low sidelobe level reported by density tapered array configuration from -13 dB to -16 dB and the result maintained for wideband operation frequency at 28 GHz, 42 GHz, and 56 GHz. However, the grating lobe has occurred due to element spacing larger than a wavelength of higher frequency (56 GHz). In this paper, an investigation was made of the performance of radiation pattern for unequally microstrip linear array antenna in frequency 42 GHz and 56 GHz by loading parasitic elements. The effect of parasitic element to the impedance, gain, and sidelobe level of unequally microstrip linear spaced tapered array also examined. The design has been simulated using Ansoft High Frequency Structural Simulator (HFSS) ver 16.0.
Volume: 6
Issue: 1
Page: 110-115
Publish at: 2017-04-01

Evaluation of the Energy Performance of the Amougdoul Wind Farm, Morocco

10.11591/.v7i2.pp692-705
Asma Ezzaidi , Mustapha Elyaqouti , Lahoussine Bouhouch , Ahmed Ihlal
This paper is concerned with the assessment of the the performance of the Amougdoul wind farm. We have determined the Weibull parameters; namely the scale parameter, c (m/s) and shape parameter, k. After that, we have estimated energy output by a wind turbine using two techniques: the useful power calculation method and the method based on the modeling of the power curve, which is respectively 134.5 kW and 194.19 KW corresponding to 27% and 39% of the available wind energy, which confirm that the conversion efficiency does not exceed 40%.
Volume: 7
Issue: 2
Page: 692-705
Publish at: 2017-04-01
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