Статьи журнала - International Journal of Wireless and Microwave Technologies
Все статьи: 454
Fractal Peano Antenna Covered by Two Layers of Modified Ring Resonator
Статья научная
Negative index of refraction has attracted a great attention in literatures. These materials are artificial structures named metamaterials has characteristics not found in nature. Microstrip antennas covered by metamaterial are very interesting areas of study. In this paper fractal Peano shape antenna is proposed and covered by two layers of modified ring resonator. The results show an enhancement in Reflection Coefficients, gain, and directivity.
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Fractal multiband microstrip patch antenna for wireless applications
Статья научная
This paper proposes a design of fractal multi-band microstrip patch antenna dedicated for wireless applications. The proposed antenna uses a FR-4 epoxy substrate having permittivity 4.4 and tangent loss to be 0.02.The microstrip antenna proposed is designed by incorporating double I-shape slot on the surface of rectangular patch and simulated by using HFSS software. Further the antenna is modified by inserting fractal shape and obtained the three frequency bands located at 2.4Ghz , 3.5Ghz and 5.50Ghz respectively and antenna parameter like VSWR, return loss, antenna gain, directivity of an antenna and bandwidth has been analyzed. The designing of proposed antenna is to be followed by fabrication by using A FR-4 substrate of thickness 1.60mm. Further, this paper discusses, the simulated and measured results comparison and analysis of the same. For designing and simulating of antennae simulation software HFSS has been used. The simulated and measured results represented are in permissible range.
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Frameproof Codes Based on The Generalized Difference Function Families
Статья научная
The frameproof codes are used in copyright protecting. Motivated by the method of constructing frameproof codes coined by D.Tonien etal, in this paper, we introduced a new combinatorial designs which in fact generalized the difference function family introduced by D.Tonien. The new designs can be constructed from difference matrix efficiently. By using the new designs we construct more larger number of frameproof codes .
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Статья научная
We are running in the communication era demanding a very large bandwidth for high speed applications. Among the available bandwidth technologies, the optical fiber seems the most appropriate and best fit. The optical fiber technology laid down at the backbone networks has almost replaced the preexisting coax cables. To extend fiber connectivity to the end user, especially in congested and remote areas is quite a difficult task in the context to cost and installation time. Therefore, the first and last mile connectivity (FLMC) is still a bottleneck in extending the beauty of optical fiber to the edge of the network. In most of the applications, the connectivity from backbone to the end user is carried out with the radio or copper links having a much lesser capacity than optical fiber. Keeping in view the nature and size of emerging applications, the FLMC needs to be addressed with the appropriate technology. To address this issue, the emerging solution is optical wireless communication like free space optics (FSO). The FSO is coming as a more promising alternative due to its properties like huge bandwidth and less cost. In this paper, we discuss the possible solution to first and last mile connectivity by FSO links and hence the gap between the optical core and the edge of network can be bridged by FSO communication in reliable and cost effective manner. The significance of the proposed work gives an everlasting impression of using FSO communication in FLMC over the existing ones. The ever increasing demand of high bandwidth can be meticulously met with the FSO communication. The simulation results show that the desirable performance is achieved and is analyzed with performance indicators like Q-factor and BER.
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GSM based Monitoring and Control of Systems
Статья научная
In this paper we have proposed a method to make a base for the monitoring and Control of systems. The monitoring and Control of systems could be from monitoring of movements in any particular area to the monitoring of any external electrical, mechanical device. Every person is pocketed with the cell. So, taking the advantage of the same we developed the system for the monitoring and Control system using GSM technology. This will provide the owner, manager of the system to know about the working or any kind of default in the system. Also the system is controlled which is needed in special circumstances and is be implemented with the help of complete circuitry which is a different module (DTMF module) has a specific code as input through GSM encoder that is processed by decoder circuitry of our system. The goal is to find an improvement over the previous surveillance systems .The maintainability of the new and improved is quite efficient as it is easy to handle it by simple software demo. The facilities provided by it such as easy handling, a secrecy support, an immediate action are granted. A prototype is built in the Windows platform using C# to demonstrate the functioning of the entire system.
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Geometric Invariant Robust Image Hashing Via Zernike Moment
Статья научная
Robust image hashing methods require the robustness to content preserving processing and geometric transform. Zernike moment is a local image feature descriptor whose magnitude components are rotationally invariant and most suitable for image hashing application. In this paper, we proposed Geometric invariant robust image hashing via zernike momment. Normalized zernike moments of an image are used as the intermediate hash. Rotation invariance is achieved by taking the magnitude of the zernike moments. Image normalization method is used for scale and translation invariance. A randomization diffusion processing enhance hashing security. The test results show that our method is robust with respect to the geometrical distortions and content preserving processing.
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HACCP and the Risk Assessment of Cold-chain
Статья научная
Considering that cold-chain involves lots of complicated operations which suffer from various uncertain factors during the process of implementing, it is inevitable to establish a sound and detailed risk assessment principle or means to guarantee the safety of cold-chain. HACCP, Hazard Analysis and Critical Control Point, is chosen to be a useful tool to analyze the processes of cold-chain, assess the potential risks for each operation link, and then identify the critical control points and give the appropriate risk weights, so as to ensure the safety, quality and reliability of the cold-chain.
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High-reliability vehicle detection and lane collision warning system
Статья научная
In the last two decades, developing Driving Assistance Systems for security has been one of the most active research fields in order to minimize traffic accidents. Vehicle detection is a vital operation in most of these applications. In this paper, we present a high reliable and real-time lighting-invariant lane collision warning system. We implement a novel real-time vehicles detection using Histogram of Oriented Gradient and Support Vector Machine which could be used for collision prediction. Thus, in order to meet the conditions of real-time systems and to reduce the searching region, Otsu’s threshold method play a critical role to extract the Region of Interest using the gradient information firstly. Secondly, we use Histogram of Oriented Gradient (HOG) descriptor to get the features vector, and these features are classified using a Support Vector Machine (SVM) classifier to get training base. Finally, we use this base to detect the vehicles in the road. Two sets generated the training data of our system a set of negative images (non-vehicles) a set of positive images (vehicles), and the test is performed on video sequences on the road. The proposed methodology is tested in different conditions. Our experimental results and accuracy evaluation indicates the efficiency of your system proposed for vehicles detection.
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ILBEECP for data aggregation in wireless sensor networks: a new technique
Статья научная
To design a load balanced energy efficient network has been a major concern in Wireless Sensor Networks (WSNs) since last many years. The load balancing energy-efficient clustering protocols are developed to attain the energy efficient network. But there was an issue related to the Cluster Head (CH) selection process. As the selected CH has to transmit the data to the sink node whether the node is located at a farther distance and this leads to the extra consumption of the energy by the current CH node. In order to overcome this, the novel approach is developed which is based on the multilayer architecture. The proposed method elects the CH and then a Leader node is elected from the volunteer nodes to gather the data from respective CH and then to transmit it to the base station. The simulation results depict that ILBEECP (Improved Load balanced energy Efficient Clustering protocol) outperforms the LBEECP (Load balanced energy Efficient Clustering protocol) in the terms of the dead node, alive nodes, residual energy, and energy consumption.
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IP Packet Filtering using Hash Table for Dedicated Real Time IP Filter
Статья научная
IP filtering is a technique used to control IP packets flow in and out of a network where Filter engine inspects at source and destination IP of incoming and outgoing packets. Here Filter engine is designed to improve the performance of the filter, i.e. to reduce the processing time of the filtering mechanism. The data structure used in the IP filter is hashing, for larger number of hosts and variety ranges IP network of hosts hashing provides much better performance than link list. Here hash function for the hash table is valid IP classes with host capacities i.e. class A, class B, class C. The IP filter engine have to compare the source and destination IP of each IP packet. In hash table technique the comparison can be done with minimum number of comparisons.
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Identifying Protein Structural Classes Using MVP Algorithm
Статья научная
A new method for the prediction of protein structural classes is constructed based on MVP (Maximum variance projection) algorithm, which is a manifold learning-based data mining method. DC (Dipeptide Composition) and PseAA (Pseudo Amino Acid) are used as conditional attributes for the construction of decision system. A DR (Dimensionality Reduction) algorithm, the so-called MVP is introduced to reduce the decision system, which can be used to classify new objects. Experimental results thus obtained are quite encouraging, which indicate that the above method is used effectively to deal with this complicated problem of protein structural classes.
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Identifying Sentiment in Web Multi-topic Documents
Статья научная
Most of web documents coverage multiple topic. Identifying sentiment of multi-topic documents is a challenge task. In this paper, we proposed a new method to solve this problem. The method firstly reveals the latent topical facets in documents by Parametric Mixture Model. By focusing on modeling the generation process of a document with multiple topics, we can extract specific properties of documents with multiple topics. PMM models documents with multiple topics by mixing model parameters of each single topic. In order to analyze sentiment of each topic, conditional random fields techniques is used to identify sentiment. Empirical experiments on test datasets show that this approach is effective for extracting subtopics and revealing sentiments of each topic. Moreover, this method is quite general and can be applied to any kinds of text collections.
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Impact of Mobility on MANETs Routing Protocols Using Group Mobility Model
Статья научная
The MANET routing protocols should be tested under realistic conditions of the network including various parameters such as network size, representative data traffic models, realistic movements of the mobile users, etc. Many factors impinge the performance evaluation of MANETs routing protocols. Mobile nodes are communicated with each other with the help of routing protocols. Unpredictable movement of a mobile node affect the routing information which directly interrupt the subsist communication. A mobility model is used to depict the realistic movements of mobile nodes in the designed scenario. In this study the group mobility model has been used to deploy the mobility effect in the scenario. The goal of this paper is to investigate the impact of group mobility on performance of routing protocols under group mobility model using QualNet simulator. In the paper it is illustrate that how the performance results of an ad hoc network protocol drastically change with the increasing node density.The various scenarios investigated with varying density of nodes in groups. Performance analysis is carried out on the basis of performance metrics under group mobility model. The outcome of this work shows that mobility has a detrimental impact on the performance of routing protocols. From the simulation results, it is shown that the DSR protocol clearly outperform all other routing protocols with increasing node density under group mobility model.
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Impact of Wall Coating on the Behavior of Indoor OWC under Diffuse Topology
Статья научная
Optical wireless communication (OWC) is an innovative technology that is gaining more attention as the demand for capacity continues to increase. It is one of the most promising alternative technologies for indoor and outdoor applications. In this paper, the effect of the inner wall coating material, color and roughness on the performance of OWC system implementing single-diffuse topology is studied. A new procedure is proposed to generate a rough surface model with predetermined statistical properties to simulate the matte painting material on the internal walls of a room. Additionally, a new technique that applies the geometrical theory of diffraction (GTD) in conjunction with a ray tracing (RT) scenario is developed to evaluate the scattered optical beam due to a primary ray incident on a Lambertian surface. The performance of the single-diffuse OWC strategy is assessed by investigating some important performance measurements such as signal strength and the bit error rate (BER) due to unavoidable ambient light which is modeled as an additive white Gaussian noise. It is shown that the surface roughness of the matte painting on the Lambertian diffuse surface has a major effect on the indoor OWC system performance.
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Implementation of a Locator-Based Route Switching Scheme for Improved Routing in Proxy Mobile IPv6
Статья научная
Proxy Mobile IPv6 (PMIPv6) is a promising IP mobility protocols that is being deployed in emerging wireless technologies. This however has a non-optimal packet route as a result of the triangular routing problem. This creates a bottle neck at the Local Mobility Anchor (LMA) thereby increasing packet delays. This paper presents the implementation of a locator-based route switching scheme on OPNET Modeler. The Mobility Access Gateway (MAG) and the LMA were enhanced by making them intelligent. This enables them to be able to check the position of the Corresponding Node (CN) with respect to the Mobile Node (MN) and also determine the available bandwidth on each link. From the checks made, a three-stage decision process is used to switch routing to the most optimal route that guarantees the best QoS. Node Models were developed for the MAG and LMA, network models were deployed and simulation tests were carried out. The results show that the developed scheme switched packets to a more optimal route according to the designed algorithm. The impact of this switching on differences between transmitted throughput at MN and the received throughput at CN was also evaluated. The receiver activity result shows a reduction in the bottleneck at the LMA-MAG link. The end-to-end delay results show over 50 milliseconds drop in packet delay as a result of the switching to a more optimal route. This shows that the packet delays result from the congestion at the LMA-MAG interface due to suboptimal routing.
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Статья научная
The design of a double layer stacked microstrip loop shaped patch antenna for multiband operation has been proposed. The design has been evolved following the iterations of a rectangular patch and a single layer loop patch structure. The material considered for the substrate of both the layers is 1.6 mm thick FR4 epoxy and the feeding technique used for the bottom patch is coaxial/ probe feed. The radiations from the bottom layer patch have been electromagnetically coupled to the upper layer patch. The main results including the reflection coefficient, bandwidth, radiation pattern, gain, directivity and VSWR for single frequency operation in each case have been discussed separately and finally compared. The comparison shows that the proposed stacked structure is clearly advantageous over the conventional rectangular patch and the single layer designed prototype in terms of the standard parameters that have been obtained. The three stage designs are useful to serve the X-band aviation applications including radio location and fixed mobile radio location.
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Improvement of ZigBee Using by Thread and Backpressure Algorithm
Статья научная
In wireless sensor networks, two approaches of tree and mesh routing are introduced to determine the path of packets during the transition process. Tree routing is a simple routing protocol with low overhead that in this protocol father-child bonds for packet transmission from the source to the destination is used. The biggest problem of routing is the increase of the number of mutations in comparison with other routing protocols. In order to improve this problem, protocols have been introduced in recent years to determine a shortcut path on the basis of the tree routing. This study is an attempt to analyse and evaluate the existing routing algorithms, identify and overcome their disadvantages, also in some other protocols, only reducing the number of mutations has been discussed. However, to achieve this goal leads to increased energy consumption and thus reducing the lifetime of the network; reducing the number of mutations is an important parameter and can reduce delays in the network, however, it should be noted the energy consumption in ZigBee networks is a very important debate. Besides that, this study will try—in addition to reducing the average number of mutations—to reduce the traffic load near the root node in the proposed algorithms. As a result, on the one hand, the application of this algorithm in ZigBee networks reduces delays and on the other hand, will also lead to balancing of load and energy in the network. Using this algorithm, the scope and lifetime of the proposed protocol-based networks can be increased.
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Статья научная
Wireless sensor network has many applications and very active research area. The coverage span of this network is very important parameter where wide coverage area is a challenge. This paper proposes an architecture for large-scale wireless sensor network (LSWSN) based on satellites and the High-Altitude Platforms (HAP) where the sensor nodes are located on the ground and a wide coverage sink station may be in the form of a satellite or a network of HAPs. A scenario is described for multilayer LSWSN and a study for the system requirements has been established showing the number of Satellites, HAPs and coverage per each sink according to the elevation angle requirements. The Satellite-HAP-Sensor multilayer LSWSN architecture has the feasibility for effective energy and earth coverage and is optimum for covering largely sparse regions.
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Integrated Guard Channel Synthesis in AESA based Airborne Surveillance Radar
Статья научная
The guard channel is very effective in eliminating side-lobe returns, both targets and discrete clutter, in airborne radar's. The ideal design criterion for the guard channel is that all the side lobes of the main antenna are covered by the guard pattern. In this paper a novel design approach of generating the guard using the elements of the main Active Electronically Scanned Array (AESA) antenna, thereby eliminating the need for a separate antenna, is presented. The ground clutter has an angle dependent Doppler and clutter discrete that leak in through the side lobes, especially the inter-cardinal elevation side lobes looking at the near range, needs to be eliminated. Towards this the design of the weighting coefficients for the guard to cover all the side lobes of the main array is discussed. Furthermore a digital threshold scheme is proposed to improve the effectiveness of guard channel in eliminating side-lobe returns. The detection loss and blanking probability are characterized for the design. The measurement results confirm that the design objectives are met.
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Intelligent and Distributed Localization of Nodes in Wireless Sensor Networks
Статья научная
In wireless sensor networks, the issue of nodes localization has taken a wide area of research. Most applications need to know the position of sensor nodes for reasons of optimal and fast data routing. In this paper, a new distributed localization algorithm based on Self Organizing Maps (SOMs) is proposed to determine the location of a node in a wireless sensor network. The proposed algorithm is classified as a range-free algorithm which uses only the connectivity information between nodes without the need to measure the time of arrival or signal strength as range-based algorithms require. It utilizes the neighborhood information and the well-known anchors' positions to calculate the estimated locations of nodes. Our algorithm is made up of two main stages. The initial estimated locations of nodes are calculated in the initialization stage, and fed to the learning stage in which a SOM is used to calculate the final estimated locations of nodes. By using the neighborhood information at the first stage, the algorithm has significantly reduced the SOM learning time and the number of iterations to converge. On the other hand, starting with real data rather than random data maximized the accuracy of the resulted locations. Furthermore, the distributed implementation of the algorithm highly alleviated the pressure on the wireless nodes which are characterized with low power and limited capabilities. The proposed algorithm has been implemented using MATLAB software and experimented by deploying different number of nodes in a specific area with different communication radio ranges. Extensive simulations evidently verified the performance of the algorithm and achieved a very good accuracy. Moreover, the algorithm proved its effectiveness with a lower average error and lower number of iterations compared to other related algorithms.
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