Effects Of The Cyclic Prefix In Siso And Miso Wimax Systems
Mohammed H. M. Nerma, Albedeir Y. G. Othman,
The cyclic prefix (CP) is actually a copy of the last portion of the data symbol appended to the front of the symbol during the guard interval (GI). By adding a CP, the channel can be made to behave as if the transmitted waveforms were from time minus infinite, and thus ensure Orthogonality, which essentially prevents one subcarrier from interfering with another (called intercarrier interference (ICI)).This paper demonstrates the effects of the CP on the single input/single output (SISO) and multi input/single output (MISO) WiMAX systems. In this work, the effect of different values of CP is shown in term of bit error rate (BER) and signal to noise ratio (SNR). This work shows also the impact of the adaptive modulation and coding (AMC) on data transmission rate with different values of the CP. The contribution of this work is twofold; first, it shows the best value of the BER for different values of the CP using AMC. Second, shows the effect fading for different values of the CP.
Mohammed H. M. Nerma Hassan Y. Ahmed, Abdallah M. Monir Ali M. Mustafa , Munzir M. Omer,
INTER-CARRIER INTERFERENCE REDUCTION TECHNIQUE IN OFDM SYSTEM BASED ON SELF CANCELLATION TECHNIQUE
Mohammed H. M. Nerma Hassan Y. Ahmed, Abdallah M. Monir Ali M. Mustafa , Munzir M. Omer,
Orthogonal frequency division multiplexing (OFDM) is considered as a one of the best modulation schemes in wireless communications. However, OFDM suffers from the sensitivity to frequency offset. This frequency offset introduces the problem of inter-carrier interference (ICI) in OFDM system. This paper presents a new self cancellation technique (modified self cancellation technique) using the self cancellation technique with zero – gab. In proposed technique a zero sub-carriers carries are used in order to mitigate the interference occurred by the main – lobe of the two adjacent sub-carriers, in addition to zeros sub-carrier, the proposed technique used self-cancellation in order to mitigate the effect of the side-lobes of other sub-carriers. In terms of carrier-to-interference ratio (CIR) and bit-error rate (BER) the modified self cancellation technique gives good results compared to that using only the conventional self cancellation techniqu
Control Strategy For Wind Energy And Hybrid Generating Systems Based On The Concept Of Power Electronics
Gaurav Mishra, Ruchi Mishra,
The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. Deregulation of energy has lowered the investment in larger power plants, which means the need for new electrical power sources may be increased in the near future. In general, this paper discusses role of modern power electronics in small size wind energy and hybrid generating systems. A new and simple control method for maximum power tracking by employing a step-up dc-dc boost converter in a variable speed wind turbine system, using permanent magnet machine as its generator, is introduced. Output voltage of the generator is connected to a fixed dc-link voltage through a three-phase diode rectifier and the dc-dc boost converter. A maximum power-tracking algorithm calculates the reference speed, corresponds to maximum output power of the turbine, as the control signal for the dc-dc converter. This paper also proposes a hybrid energy system consisting of a wind turbine, a photovoltaic source, and a fuel cell unit designed to supply continuous power to the load. A simple and economic control with dc-dc converter is used for maximum power extraction from the wind turbine and photovoltaic array. Due to the intermittent nature of both the wind and photovoltaic energy sources, a fuel cell unit is added to the system for the purpose of ensuring continuous power flow.
ONTOLOGY MINING FOR PERSONALIZED WEB INFORMATION GATHERING
Miss. Deshmukh, Rupali R., Prof. Keole R.R,
As a model for knowledge description and formalization, ontologies are widely used to represent user profiles in personalized web information gathering. However, when representing user profiles, many models have utilized only knowledge from either a global knowledge base or user local information. In this paper, a personalized ontology model is proposed for knowledge representation and reasoning over user profiles. This model learns ontological user profiles from both a world knowledge base and user local instance repositories. The ontology model is evaluated by comparing it against benchmark models in web information gathering. User profiles represent the concept models possessed by users when gathering web information. A concept model is implicitly possessed by users and is generated from their background knowledge. While this concept model cannot be proven in laboratories, many web ontologists have observed it in user behaviourThe results show that this ontology model is successful.
Many cryptographic algorithms (e.g., AES, HMAC) require the establishment of shared keying material in advance. The Federal key agreement schemes document is based on ANSI X9.42 agreement of symmetric keys using discrete logarithm cryptography, ANSI X9.44 key agreement and key transport using factoringbased cryptography and ANSI X9.63 key agreement and key transport using elliptic curve cryptography. It is necessary for the keying material to establish and maintain cryptographic keying relationships. Shared secret is a value computed using a prescribed algorithm and combination of keys belonging to the participants in the key establishment scheme. The public key algorithms like RSA are becoming the standards for the encryption. But the major threat of using RSA is, it is multiplicative and hence does not guarantees the uniqueness of the key and further it does not stand true to the dynamic demands of the system. Practically it is proved that such public key algorithms are slow as compared to the symmetric key algorithms. The PKI has provided a strong platform for the RSA algorithm. In view to overcome above limitations in this article a cryptographic method of key management has been proposed that uses the symmetric key algorithm (Blow fish) over the asymmetric key algorithm (RSA algorithms). The symmetric key algorithms do not have any key management scheme. Further, the proposed work uses ant colony based evolutionary computing algorithm to meet the requirement in which the shared secret value changes dynamically with time and matures with the time as numbers of communications amongst the legitimate users increases. The method proposed has been found have system of key management, which apart from being faster has all the security features. The efficiency in time management in all the aspects namely Key Generation, key Transmission, Key Revocation, Encryption and decryption is found to be much better than the widely used PKI. This speed do not compromise the security aspects of the system, in fact this efficient time management has helped to build up the secured transmission. Practically to avoid the time of encryption and decryption using the public key infrastructure certifying authorities use the session keys that use symmetric key algorithm. This method is not providing any authentication mechanism. The proposed system stands balanced and solves all the problems mentioned above. Overall it is a key management scheme for the symmetric key algorithms.
Maintainability of Software using Aspect Oriented Programming for Process quality Analysis
Dr.V.Khanaa, Krishna Mohanta,
Among all the phases in software development cycle, maintainability forms the key phase. Once the software is engineered, Software maintenance is the most effort and cost consuming part. A quality software must be adaptable to any real time working conditions. In a component-based system, different components are integrated, enrichment/improvement of a component to make it adaptable to prevailing conditions require more cost. This research presents the modeling work and prototyping techniques, which highlights the importance of project quality analysis for perspective maintainability. Here we are proposing a mathematical approach for time computation which is the sum of response time and time for solution generation. For efficient analysis we require high execution speed for handling complex algorithms and huge data volumes. For this we are providing aspect oriented programming techniques which increase the development speed, modularity that outputs quality products
Performance Evaluation of IEEE 802.16 Grids using scheduling Algorithms
Krishna Mohantn, Dr.V.Khanaa,
IEEE 802.16 standard was designed to support the bandwidth demanding applications with quality of service .Bandwidth is reserved for each application to ensure the QoS. For variable bit rate applications, however, it is difficult forth subscriber station (SS) to predict the amount of incoming data. The key concern on the bandwidth allocation and scheduling for non real time traffic are the fulfillment of its minimum throughput requirement and improvement of bandwidth utilization with acceptable delay. This paper proposes a simple and efficient scheduling framework for allocating bandwidth to non real time Polling Service (nrtPS) users in IEEE 802.16 grid. In this framework, jointly selective repeat ARQ at the MAC layer and adaptive modulation and coding techniques at the physical are considered. Numerical simulations demonstrate that the proposed scheduling approach provides a graceful compromise between bandwidth utilization and packet delivery delay while maintaining the minimum throughput requirements of nrtPS applications. Thus proves the efficiency of the proposed framework. The simulation is done for unicast scenario.
The rapid growth of the computers that are interconnected, the crime rate has also increased and the ways to mitigate those crimes has become the important problem now. In the entire globe, organizations, higher learning institutions and governments are completely dependent on the computer networks which play a major role in their daily operations. Hence the necessity for protecting those networked systems has also increased. In the proposed system, we have designed fuzzy logic-based system for effectively identifying the intrusion activities within a network. Currently available intrusion detection systems focus mainly on determining uncharacteristic system events in distributed networks using signature based approach. Due to its limitation of finding novel attacks, we propose a hybrid model based on improved fuzzy and data mining techniques, which can detect both misuse and anomaly attacks. Our aim is to reduce the amount of data retained for processing i.e., attribute selection process and also to improve the detection rate of the existing IDS using data mining technique. We then use improved Kuok fuzzy data mining algorithm, which in turn a modified version of APRIORI algorithm, for implementing fuzzy rules, which allows us to construct if-then rules that reflect common ways of describing security attacks. We applied f
Web Services are based on distributed technology and provide standard means of interoperating between different software applications across and within organizational boundaries. Web Services technologies allow interaction between applications. Sometimes a single service given alone does not meet user’s needs. In this case, it is necessary to compose several services in order to achieve the user’s goal. Quality of Service (QoS) support in web services plays a great role for the success of this emerging technology. In this paper, we presentQoS broker- based architecture for web services. The main goal of the architecture is to support the client in selecting web services based on his/her required QoS It also presents an efficient method to finding the suitable web service based on the consumer’s requirements along with QoS. We intend to use this architecture for several services like Loan system,location based search etc.
Automated Video Surveillance System With Sms Alert
H.Venkateswara Reddy, B.Suresh Kumar,
in this paper presents a technique for motion detection that incorporates several innovative mechanisms. For example, our proposed technique stores, for each pixel, a set of values taken in the past at the same location or in the neighborhood. It then compares this set to the current pixel value in order to determine whether that pixel belongs to the background, and adapts the model by choosing randomly which values to substitute from the background model. This approach differs from those based upon the classical belief that the oldest values should be replaced first. In this future enhancement of paper is remotely we are checking and providing the security to our system. So whenever user getting SMS from server system and the background image is updated whenever the system is detecting a motion.
We are in an era of considering environmental resource constraints along with more IT goals. Environmental impact and power consumption are becoming crucial architectural systemic quality metrics. Saving energy is a much more complex architectural problem, requiring a coordinated array of tactics, from architectural power management capacity planning techniques to optimizing operational processes and facilities design. This paper concentrates on how cloud computing provide some interesting architectural constructs, some great potential from a monetary aspect, and a very real option to provide a more environmentally friendly computing platform. This paper also deals with the definition of reduced energy consumption which is influenced by reduced greenhouse gas emissions and reduced operational costs for the data center and business.
Forecasting is the establishment of future expectations by the analysis of past data, or the formation of opinions. Forecasting of the wind power generation may be considered at different time scales, depending on the intended application. Rapid growth of wind power generation in many countriesaround the world in recent years has highlighted the importance of wind power prediction however, wind power is a complex signal for modeling and forecasting.The wind sector in India has seen phenomenal growth during the past few years, catapulting India to fourth position in the world in terms of wind power installations.Despite the performed research work in the area more efficient wind power forecast methods are still demand. In this paper new strategy is proposed for this purpose. Forecast engine of the proposed strategy is an artificial neural network (ANN) owning artificial functions as the activation function of its hidden nodes. Moreover a new back propagation algorithm can be used. ANN is the best tool for forecasting the demand in electricity. The efficiency of the proposed prediction strategy is shown for forecastingof both wind power output of wind farms and aggregated wind generation of power system. Also perception rule, that rule help the wind power calculation such as total power, average, needed power, update and demand.
Optimization of Speed and Feed Rate for a Low Vibration and Better Surface Finish in Mild Steel on Lathe
Jinesh Kumar Jain
Machining is a complex process in which many variables can deleterious the desired results. Among them, cutting tool vibration is the most critical phenomenon which influences dimensional precision of the components machined, functional behavior of the machine tools and life of the cutting tool. In a machining operation, the cutting tool vibrations are mainly influenced by cutting parameters like cutting speed, depth of cut and tool feed rate. The cutting tool vibration signals have been collected through a data acquisition system supported by RS-232 software. On mild steel, the collecting data at various parameters like depth of cut, speed, feed rate etc. A number of data have been recorded by varying the above parameters. On the completion of experimental work MATLAB has been used to analyze the result for vibration in metal cutting tool and also to predict the optimum behavior of the system under any cutting condition within the operating range.
WSN are collection of spatially distributed autonomous actuator devices called sensor nodes. Target tracking under surveillance is one of the main applications of WSN. We introduce an edge detection algorithm to generate each face further in such a way that the nodes can prepare ahead of the target’s moving, which greatly helps tracking the target in a timely fashion and recovering from special cases, e.g., sensor fault, loss of tracking, Also, we develop an optimal selection algorithm to select which sensors of faces to query and to forward the tracking data. a new tracking framework, called Face Track, which employs the nodes of a spatial region surrounding a target, called a face. In target tracking, sensor nodes are informed when the target under surveillance is discovered. Some nodes detect the target and send a detection message to the nodes on the target’s expected moving path. So nodes can wake up earlier. Face tracking is a new tracking framework, in which divides the region into different polygons called faces. Instead of predicting the target location separately in a face, here estimate the targets movement towards another face. it enables the wireless sensor network to be aware of a target entering the polygon a bit earlier
