Volume 4 ~ Issue 8

With the rapid deployment of new wireless devices and applications, the last decade has witnessed a growing demand for wireless radio spectrum. However, the policy of fixed spectrum assignment produces a bottleneck for more efficient spectrum utilization, such that a great portion of the licensed spectrum is severely under-utilized. So the concept of cognitive radio was introduced to address this issue.The inefficient usage of the limited spectrum necessitates the development of dynamic spectrum access techniques, where users who have no spectrum licenses, also known as secondary users, are allowed to use the temporarily unused licensed spectrum. For this purpose we have to know the presence or absence of primary users for spectrum usage. So spectrums sensing is one of the major requirements of cognitive radio.Many spectrum sensing techniques have been developed to sense the presence or absence of a licensed user. This paper evaluates the performance of the energy detection based spectrum sensing technique in noisy and fading environments.The performance of the energy detection technique will be evaluated by use of Receiver Operating Characteristics (ROC) curves over additive white Gaussian noise (AWGN) and fading channels.

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Author Keywords:- Cognitive Radio(CR), Spectrum Sensing, Energy Detection, Detection Probability(PD),Probability of miss-detection(PM) and Probability of false alarm(PFA)

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 07

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© Copyright 2014, All rights reserved.

The measurement uncertainties of Fundamental Physical Constants should take into account all possible and most influencing factors. One from them is the finiteness of the model that causes the existence of a-priori error. The proposed formula for calculation of this error provides a comparison of its value with the actual experimental measurement error that cannot be done an arbitrarily small. According to the suggested approach, the error of the researched Fundamental Physical Constant, measured in conventional field studies, will always be higher than the error caused by the finite number of dimensional recorded variables of physical-mathematical models. Examples of practical application of the considered concept for measurement of fine structure constant, speed of light and Newtonian constant of gravitation are discussed.

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Author Keywords:- A priori error analysis, information theory, theory of similarity, theory of measurement, fundamental physical constants

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 07

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© Copyright 2014, All rights reserved.

This paper presents of the influence on surface roughness of Co28Cr6Mo medical alloy machined on a CNC lathe based on cutting parameters (rotational speed, feed rate, depth of cut and nose radius).The influences of cutting parameters have been presented in graphical form for understanding. To achieve the minimum surface roughness, the optimum values obtained for rpm, feed rate, depth of cut and nose radius were respectively, 318 rpm, 0,1 mm/rev, 0,7 mm and 0,8 mm. Maximum surface roughness has been revealed the values obtained for rpm, feed rate, depth of cut and nose radius were respectively, 318 rpm, 0,25 mm/rev, 0,9 mm and 0,4 mm.

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Author Keywords:- Co28Cr6Mo, Cutting Parameters, Machinability, Surface roughness.

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 08

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© Copyright 2014, All rights reserved.

As an answer of long growing frustration of waterfall Software development life cycle concepts, agile software development concept was evolved in 90's. The most popular agile methodologies is the Extreme Programming (XP). Most software companies nowadays aim to produce efficient, flexible and valuable Software in short time period with minimal costs, and within unstable, changing environments. This complex problem can be modeled as a multi-agent based system, where agents negotiate resources. Agents can be used to represent projects and resources. Crucial for the multi-agent based system in project scheduling model, is the availability of an effective algorithm for prioritizing and scheduling of task. To evaluate the models, simulations were carried out with real life and several generated data sets. The developed model (Multi-agent based System) provides an optimized and flexible agile process scheduling and reduces overheads in the software process as it responds quickly to changing requirements without excessive work in project scheduling.

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Author Keywords: - Agile Software development process methodologies, Extreme programming, Agents and Multi-agents.

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 09

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© Copyright 2014, All rights reserved.

Extrusion can be defined as the process of subjecting a material to compression so that it is forced to flow through an opening of a die and takes the shape of the hole. Multi-hole extrusion is the process of extruding the products through a die having more than one hole. Multi-hole extrusion increases the production rate and reduces the cost of production. In this study the ram force has calculated experimentally for single hole and multi-hole extrusion. The comparison of ram forces between the single hole and multi-hole extrusion provides the inverse relation between the numbers of holes in a die and ram force. The experimental lengths of the extruded products through the various holes of multi-hole die are different. It indicates that the flow pattern is dependent on the material behavior. The micro-hardness test has done for the extruded products of lead through multi-hole die. It is observed that the hardness of the extruded lead products from the central hole is found to be more than that of the products extruded from other holes. The study suggests that multi-hole extrusion can be used for obtaining the extruded products of lead with varying hardness. The micro-structure study has done for the lead material before and after extrusion. It is observed that the size of grains of lead material after extrusion is smaller than the original lead.

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Author Keywords: - Extrusion, ram force, ram travel, hardness, grain size, extruded length

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 06

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© Copyright 2014, All rights reserved.

Cars are a very important part of this modern world because they give luxury and comfort. Even though they are comfortable, some problems always keep arising on the safety side. After a lot of research they rectified certain problems using air bags, auto parking, turbo charger, pedal shift…, etc. And now we are going to discuss about one such problem that arises on the safety side. An unsuspected accident occurs when people smash their fingers in between the car doors. Due to this kind of accident around 120,000 people are injured every year. But this was not taken as a very major safety concern for the customer. To avoid this kind accident due to car doors, we are introducing "SAFETY DOOR LOCK SYSTEM" with the help of "HYDRAULIC PISTON AND IR SENSORS". The major working process of the "SAFETY DOOR LOCK SYSTEM"is, when a person places his/her hand or fingers in the gap between the door and the outer panel, at the time when the closing action of the door takes place, the Sensors start to transmit the Infra Red Rays to the Receivers at the other end, and so even if someone closes the door without anybody‟s knowledge the hydraulic piston will automatically come out and stop the door from closing and prevent the person from the unsuspected accident and minor injuries by the car door and ensure maximum safety to the customer.

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Author Keywords:- ..

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 11

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© Copyright 2014, All rights reserved.