-
Performance of Superconducting Synchronous Generator for Three-Phase Short-Circuit at Its Terminals
Issue:
Volume 4, Issue 3, June 2016
Pages:
44-50
Received:
24 March 2016
Accepted:
8 April 2016
Published:
7 May 2016
Abstract: In this paper, three-phase short-circuit at the terminals of a superconducting synchronous generator is simulated by using MATLAB. In this simulation, a single screened superconducting generator directly connected to power system is considered and two operating cases are investigated: the first case is that the fault is permanent and the second case is that the fault is cleaned by a protection system. To show the effects of this short-circuit and the performance of the superconducting synchronous generator for both cases, the deviations of armature momentary currents, angular speed and field current are plotted. In order to compare the obtained results, the present simulations for the both cases mentioned above are repeated for a conventional synchronous generator having the same rating as considered superconducting counterpart, which is directly connected to power system, and the deviations of the same variables as considered for the superconducting synchronous generator are also given in the paper.
Abstract: In this paper, three-phase short-circuit at the terminals of a superconducting synchronous generator is simulated by using MATLAB. In this simulation, a single screened superconducting generator directly connected to power system is considered and two operating cases are investigated: the first case is that the fault is permanent and the second cas...
Show More
-
Fast Type Recognition of Missive Insulator Leakage Current Data Using Spark
Issue:
Volume 4, Issue 3, June 2016
Pages:
51-56
Received:
21 May 2016
Published:
24 May 2016
Abstract: Performance is the key issue in power big data applications. One of main challenges is how to exploit these technologies in building power big data processing platform and facilitating science discoveries such as those in electric power systems. This paper explores how Spark and Cloud computing can accelerate performance of missive insulator leak current data pattern recognition. We have designed and implemented the Parallel KNN(k-NearestNeighbor) algorithm using Spark and then deployed onto the Aliyun E-MapReduce cloud computing platform. The results from experiments shows the performance and scalability can be enhanced through these advanced technologies.
Abstract: Performance is the key issue in power big data applications. One of main challenges is how to exploit these technologies in building power big data processing platform and facilitating science discoveries such as those in electric power systems. This paper explores how Spark and Cloud computing can accelerate performance of missive insulator leak c...
Show More
-
RFIA: A Novel RF-band Interference Attenuation Method in Passive Radar
Zeinab Shamaee,
Mohsen Mivehchy
Issue:
Volume 4, Issue 3, June 2016
Pages:
57-62
Received:
2 May 2016
Accepted:
11 May 2016
Published:
25 May 2016
Abstract: Passive radars get benefit from transmitter signals in the environment for target detection. One of the most important challenges in these radars is multipath and direct path interferences that enter the target and reference antennas. This article expressed the types of weakening, and multi-step structure to mitigate the mentioned signals in passive radars. In the RF-band Interference Attenuation (RFIA) Method, at the first step the strongest interference component is mitigated by controlling the phase and amplitude. In next steps, other interference components are similarly nulled. This structure leads to separate mitigation for each interference components. Simulation results show the success of RFIA method to reduce dynamic range of analog-to-digital converter and, accordingly, the number of required bits for this converter.
Abstract: Passive radars get benefit from transmitter signals in the environment for target detection. One of the most important challenges in these radars is multipath and direct path interferences that enter the target and reference antennas. This article expressed the types of weakening, and multi-step structure to mitigate the mentioned signals in passiv...
Show More
-
Increased Accuracy in Image Segmentation Considering the Modular Method Based on Texture Characteristics and Super Pixel
M. Dabbaghha,
M. Dashtbayazi,
S. Marjani,
M. Sabaghi
Issue:
Volume 4, Issue 3, June 2016
Pages:
63-67
Received:
13 May 2016
Accepted:
23 May 2016
Published:
4 June 2016
Abstract: To solve the problem of segmenting an image into homogeneous regions with large area, this paper proposes an efficient algorithm that is based optimization base on modularity and super pixel method. Due to the fact that a very small areas of the image before segmentation, the proposed algorithm automatically merged with neighboring small areas and to make larger modules. When the modularity pictures after the merger to reach its maximum stop, leading to the production of segmentation algorithms are final. To keep repetitive patterns in a homogeneous area, a feature based on its histogram modularity with features like color and eventually identified two areas by creating a similarity matrix, it is suggested. So that the problem of segmentation and complexity of the problem to some extent eliminate in a way that due to the combined areas can be achieved for repetitive patterns. Simulation results show that the algorithm has good accuracy.
Abstract: To solve the problem of segmenting an image into homogeneous regions with large area, this paper proposes an efficient algorithm that is based optimization base on modularity and super pixel method. Due to the fact that a very small areas of the image before segmentation, the proposed algorithm automatically merged with neighboring small areas and ...
Show More
-
Measure and Evaluate Delay Time for Wakeup on Lan (Wol) Method of OpenFlow Switch
Issue:
Volume 4, Issue 3, June 2016
Pages:
68-72
Received:
18 May 2016
Accepted:
1 June 2016
Published:
17 June 2016
Abstract: Currently, there are many ways to save energy for the switch such as change the operating modes to low power modes: SLEEP PORT and SLEEP SWITCH when there is no traffic flowing through the Ethernet ports. The switch will be waked up to normal modes when traffic flows pass through it. However, the changes of the modes of the OpenFlow Switch will create DELAY-TIME. If we know DELAY-TIME, then we will make routing algorithms and get appropriately mechanisms to ensure no impact on the transmission of data and loss packets. In this paper, we propose a remedy to measure and evaluate DELAY-TIME when we use the Wakeup On Lan (WOL) method for OpenFlow switch based on NetFPGA platform.
Abstract: Currently, there are many ways to save energy for the switch such as change the operating modes to low power modes: SLEEP PORT and SLEEP SWITCH when there is no traffic flowing through the Ethernet ports. The switch will be waked up to normal modes when traffic flows pass through it. However, the changes of the modes of the OpenFlow Switch will cre...
Show More
-
Page Replacement Algorithm for NAND Flash Used in Mobile Devices
Hai Jun Zhang,
Wan Jun Yu
Issue:
Volume 4, Issue 3, June 2016
Pages:
73-77
Received:
16 June 2016
Published:
17 June 2016
Abstract: In modern society, intelligent devices equipped with flash memory are very popular. It has many wonderful characteristics, such as small, fast, little consumption, shock resistance and so on. Flash memory is divided into NOR memory and NAND memory. The NOR memory can be quickly read with byte data which is developed into data memory for code storage. A new algorithm is needed to optimize the performance of the flash memory. In this paper, we propose a new strategy for replacement to focus on reducing the execution time of the replacement cost and I / O, which is to improve the performance of the algorithm performance. Trace-driven method has a better performance than the existing algorithms in terms of cost and execution time.
Abstract: In modern society, intelligent devices equipped with flash memory are very popular. It has many wonderful characteristics, such as small, fast, little consumption, shock resistance and so on. Flash memory is divided into NOR memory and NAND memory. The NOR memory can be quickly read with byte data which is developed into data memory for code storag...
Show More
-
A Robust and Adaptive Line Echo Canceller
Issue:
Volume 4, Issue 3, June 2016
Pages:
78-82
Received:
14 July 2016
Published:
15 July 2016
Abstract: In the actual communication system, the line echo is a frequent problem, so the line echo canceller is necessary. Traditionally, the cancellers are designed according to line noises based on the Gaussian noise model. However, the noises do not obey the Gaussian distribution; therefore the performances of algorithms decrease, even cannot be used. In order to solve this problem, this paper proposes a line echo canceller based on alpha stable distribution model. The Method in this line echo canceller has Robust and Adaptive. Alpha stable distribution modeling impulse noise, and under the rule of minimum average p norm, adaptive time delay estimator offsets the echo. This method can not only effectively offset the line echo with the Gaussian noise, but also to have the effect of good to echo with impulse noise. Theoretical analysis and computer simulation experiments show that it is very kind of the line echo canceller. It is robust to impulse noises and adaptive to echo cancellation.
Abstract: In the actual communication system, the line echo is a frequent problem, so the line echo canceller is necessary. Traditionally, the cancellers are designed according to line noises based on the Gaussian noise model. However, the noises do not obey the Gaussian distribution; therefore the performances of algorithms decrease, even cannot be used. In...
Show More
