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| Scanning the Issue | p. 397 |
Shiban K Koul
DOI:10.4103/0377-2063.90144 |
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| Hybrid Radio and Optical Communications for Energy-efficient Wireless Sensor Networks | p. 399 |
Sashigaran Sivathasan, Dominic O'Brien
DOI:10.4103/0377-2063.90146 A wireless sensor network (WSN) consists of a large number of networked sensor nodes deployed to sense and report a particular phenomenon to a base station. One of the main design considerations for WSNs is the energy consumption of the individual sensor nodes. Currently, most WSNs are radio frequency (RF) based, and communications account for a significant portion of the energy expended. The hybrid radio frequency/free space optical (RF/FSO) WSN is proposed to lower energy consumption. The RF and FSO link models used for the RF/FSO WSN are first discussed. Next, the energy expended by the sensor nodes for sensing, data processing and communications is modeled. These models are used to simulate the lifetime of the WSN. To investigate the energy efficiency of the RF/FSO WSN, an RF-only WSN is used for comparison. Simulations show that the average energy consumed by the nodes in the RF/FSO network is significantly lower than that of the RF-only network, thus increasing the lifetime of traditional RF-based WSNs. |
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| A Novel Approach to the Design of MESFET-based MMIC Switches Using Common-gate Parameter Extraction | p. 407 |
Rajesh Kumar Prabakaran, Ananjan Basu, Shiban K Koul
DOI:10.4103/0377-2063.90149 This paper describes a new approach to the Single-pole Double-throw (SPDT) switch design using MESFETs. The device models were extracted from measured data for a number of FETs, and verified in the frequency band of 1-20 GHz. A switch was designed using these device models, and showed good results in simulation. |
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| Algorithm for Web Server Security | p. 413 |
Brijendra Singh, Pooja Agarwal
DOI:10.4103/0377-2063.90150 The Web application layer is the number one target for malicious online attacks. Millions of Web sites regulate access to highly sensitive information including social security numbers, credit card numbers, names, addresses, birthdates, intellectual property, financial records, trade secrets, medical data, and more. These data must be rigorously protected from intruders. To reduce the risk of losses, brand damage, theft of intellectual property, legal liability, and fines, enterprises need timely information about how Web sites are penetrated and how they can be defended. This article presents an algorithm to generate the security report. The proposed algorithm uses the experimental data of 69 different Indian research/educational Web sites and the generated security report took place after checking all the possible prospective of obtained experimental attributes dataset. This article also presents the changes in the security settings of the Indian Web sites within 3 years, on the bases of open port's study of 3 years experimental result. Based on port scanning, preventive security measures can be taken by organizations as a policy matter. |
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| A Fake Content Remove Scheme using Binomial Distribution Characteristics of Collective Intelligence in Peer-to-Peer Environment | p. 423 |
ByungRae Cha, Sun Park, JongWon Kim
DOI:10.4103/0377-2063.90151 A P2P (Peer-to-Peer) network can be created or destroyed automatically because it is based on the structural characteristic of being promoted by peer communities' free participation. While users can share resources they want in a P2P, there are also many resources they do not want such as fake contents. As one method of removing fake contents, it is suggested to use collective intelligence in P2P environment. This study is intended to design an efficient contents reputation system using dynamic user's collective intelligence in P2P environment. Collective intelligence has been applied to decision making more importantly thinks to the emergence of new information and communication technology and experts use this term to create a noble insight by combining a group of people's behaviors, selection and ideas. Collecting a group of peoples decision making allows one to induce a statistical conclusion individuals does not know. To verify this, we simulate the real reputation of contents by trustworthy evaluation and unbiased evaluation. |
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| T-connected Transformer with a Voltage Source Converter for Voltage Control of an Isolated Asynchronous Generator | p. 430 |
Gaurav Kumar Kasal, Bhim Singh
DOI:10.4103/0377-2063.90153 This paper presents a voltage source converter (VSC)-based voltage controller for an isolated asynchronous generator driven by constant-speed prime movers such as biogas, biodiesel, and gasoline engines and feeding 3-phase 4-wire consumer loads. The proposed controller consists of an Insulated Gate Bipolar junction Transistor (IGBT)-based VSC with a capacitor at its Direct Current (DC) link. The neutral terminal for the consumer loads is created using a T-connected transformer. The proposed system is modeled and simulated using Simulink and Power System Block set toolboxes. Extensive simulation results are presented to demonstrate the capability of the controller as a harmonic eliminator, a load balancer, along with as a voltage controller. |
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| Multiband Rectangular Microstrip Antennas | p. 437 |
Amit A Deshmukh, KP Ray
DOI:10.4103/0377-2063.90160 The dual-band microstrip antennas (MSAs) are realized by placing the stub on the edges of the patch or by cutting a slot at an appropriate position inside the patch. The multiband MSAs are realized by using the combination of the slot and stub. In this paper, by cutting a rectangular slot on the radiating edge and half U-slot on the nonradiating edge of a rectangular MSA, a dual- and triple-band rectangular MSA are proposed. These slots are of nearly quarter wave in length and by changing their lengths, tuning of the frequencies is realized. Also, the multiport network models for these multiband MSAs are proposed, which helps in understanding the mode distributions at slot and patch frequencies. To realize the higher gain, the suspended configurations of these multiband antennas are also proposed. A good agreement is obtained between the simulated, multiport network model, and measured results. |
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| Fuzzy Tracking Control for Indirect Field-oriented Induction Machine Using Integral Action Performance | p. 443 |
Moez Allouche, Mohamed Chaabane, Mansour Souissi, Driss Mehdi
DOI:10.4103/0377-2063.90164 This paper deals with the synthesis of fuzzy controller applied to the induction motor with a guaranteedH∞ tracking performance. First, the Takagi-Sugeno fuzzy model is employed to approximate a nonlinear system in the synchronous d-q frame rotating with electromagnetic field-oriented. Next, a fuzzy observer-based fuzzy tracking controller is designed to stabilize the induction motor and guaranteed a minimum disturbance attenuation level for the closed-loop system. The rotor flux is unavailable for measurement and it is estimated by a fuzzy observer. An integral action is added to the new parallel distributed compensation fuzzy controller related to the tracking to avoid static errors. The gains of fuzzy control and fuzzy observer are obtained by solving a set of Linear Matrix Inequality. Finally, simulation result is given to demonstrate the controller's effectiveness. |
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| Frequency and Time Domain Characterization of a Novel Hexagonal-shaped Microstrip Antenna for Ultra Wideband Applications | p. 452 |
Mithilesh Kumar, Ananjan Basu, Shiban K Koul
DOI:10.4103/0377-2063.90167 This paper presents frequency- and time-domain characterization of a new hexagonal-shaped monopole antenna with small slots for ultra-wideband (UWB) applications. The antenna was simulated using commercial software tools (CST) microwave studio and Agilent ADS. Neltec make a soft substrate having a dielectric constant of 2.2 and a board thickness of 0.254 mm (10 mil) was used to fabricate the proposed antenna. Frequency-domain characterization using an automatic network analyzer showed return loss less than -10 dB over the entire UWB frequency band. To study the effect of various parameters on the antenna performance, the detailed parametric study was carried out. The radiation patterns and group delay characteristics were measured in an anechoic chamber. Using an Agilent DSO9000A oscilloscope, time-domain characterization of the antenna was carried out. The simulated and measured results in the time domain showed good agreement. It was observed that the proposed antenna shows reasonably good frequency characteristics and time-domain pulse distortion is small indicating usefulness of the antenna for UWB communication applications. |
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| Performance Evaluation of Shot Boundary Detection Metrics in the Presence of Object and Camera Motion | p. 461 |
Krishna K Warhade, Shabbier N Merchant, UB Desai
DOI:10.4103/0377-2063.90172 Partitioning a video into shots is an important step for video indexing. We have presented the performance of various traditional metrics that are generally used to detect shot boundaries. In this paper, we evaluated shot boundary detection metrics, such as likelihood ratio and color ratio histogram in Red Green Blue (RGB) and Hue Saturation, Value (HSV) color space for three different action and thriller movies. These movies consist of large number of frames with object and camera motion. The pixel difference and Chi-square shot boundary detection metrics in Luma and Chrominance Components (YUV) color space has been tested for five different movies. The results were evaluated in terms of Recall, Precision, and F1 measure for all these movies. It has been observed that these results are affected by the disturbance due to the motion in the consecutive frames. The false positives and miss detection of shot boundaries in all the tested metrics are due to fast camera and object motion. An algorithm has been proposed for shot boundary detection by using dual tree complex wavelet transform in the presence of motion. Performance comparison of the proposed algorithm with the traditional metrics validates its effectiveness in terms of improved Recall, Precision, and F1 score. |
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| Neural Network Based Voltage and Frequency Controller for Isolated Wind Power Generation | p. 467 |
Bhim Singh, Shailendra Sharma
DOI:10.4103/0377-2063.90174 This paper deals with an artificial neural network based control of the voltage and frequency (VF) of autonomous wind power generation using an isolated asynchronous generator (IAG) feeding three-phase four-wire loads. The reference generator currents are estimated using the adaptive linear neuron and its training through least mean square (LMS) algorithm to control the VF of an IAG system. Three-leg voltage source converter (VSC) with an isolated T-connected transformer is used as an integrated VSC. The integrated VSC with a battery energy storage system is used to control the active power of the wind energy conversion system (WECS). Bi-directional power flow capabilities of the proposed VF controller in WECS are demonstrated through simulation results. The proposed controller functions as a VF regulator, a load leveler, a load balancer and a harmonic eliminator in the WECS. The WECS is modeled and simulated in the MATLAB using the Simulink and the sim power system toolboxes. |
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Practical Blind Approach for Joint Detection and Parameter Assessment in Direct Sequence Code Division Multiple Access Systems  | p. 478 |
Javad Afshar Jahanshahi, Mohammad Eslami, Seyed Ali Ghorashi
DOI:10.4103/0377-2063.90177 In this paper, the blind code extraction of Direct Sequence Code - Division Multiple Access signals is considered based on independent component analysis (ICA), some propositions are defined in order to estimate the number of active users, to distinguish between correct and incorrect extracted codes, and also to determine the quality of detection along with the ICA-based blind detection procedure. These propositions are used to improve the performance of the ICA blind detection-based method. Principal component analysis and gaussian mixture model are employed as analyzing tools in proposed criteria. Experimental results show that the defined criteria are verified. |
