344 research outputs found

    How to Play Unique Games on Expanders

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    In this note we improve a recent result by Arora, Khot, Kolla, Steurer, Tulsiani, and Vishnoi on solving the Unique Games problem on expanders. Given a (1−ε)(1-\varepsilon)-satisfiable instance of Unique Games with the constraint graph GG, our algorithm finds an assignment satisfying at least a 1−Cε/hG1- C \varepsilon/h_G fraction of all constraints if ε<cλG\varepsilon < c \lambda_G where hGh_G is the edge expansion of GG, λG\lambda_G is the second smallest eigenvalue of the Laplacian of GG, and CC and cc are some absolute constants

    Hitting Diamonds and Growing Cacti

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    We consider the following NP-hard problem: in a weighted graph, find a minimum cost set of vertices whose removal leaves a graph in which no two cycles share an edge. We obtain a constant-factor approximation algorithm, based on the primal-dual method. Moreover, we show that the integrality gap of the natural LP relaxation of the problem is \Theta(\log n), where n denotes the number of vertices in the graph.Comment: v2: several minor changes

    Design and Development of Mono Leaf Spring by using Composite Material (Epoxy-Carbon Fiber)

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    According to the demand of recent world, the more concentration is on weight reduction in automobiles. The possible weight reductions are wheel assembly, axles, and part of the weight of suspension spring and shock absorbers. The leaf spring accounts for 10-20% of the un-sprung weight. The composite materials made it possible to reduce the weight of machine element without any reduction of the load carrying capacity. Because of composite material\u27s high elastic strain energy storage capacity and high strength-to weight ratio compared with those of steel. FRP spring also have excellent fatigue resistance and durability. But the weight reduction of the leaf spring is achieved not only by material replacement but also by design optimization. Weight reduction has been the focus of automobile manufacturers in the present scenario. The replacement of steel with optimally designed composite leaf spring can provide 75%-78% weight reduction. The material selected is carbon epoxy against conventional steel. The optimization study consists of use of software\u27s such as NASTRAN / ANSYS software. The experimentation on UTM is carried out and results are compared. Moreover, the composite leaf spring has lower stresses compared to steel spring. All these will result in fuel saving which will make countries energy independent because fuel saved is fuel produced

    Analysis of Roller Unit Assembly of Calcination Drum

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    Solid waste management is posing a great problem as the population is increasing day by day. The municipal sewage waste has to be disposed properly otherwise it will lead to air pollution and cause the serious effects on the health of human beings. The most common practice adopted is generating methane from municipal solid waste. For this purpose it is necessary that the municipal solid waste which is sent for further processing should be in the form of homogenous mass. In order to form the homogenous mass it is necessary that it should be separated in degradable and non degradable. This degradable waste is then converted into fine particles. To achieve this task the engineers have designed a special instrument named Calcination Drum. Usually Calcination Drum is also known as Rotary Kilns. In primary stage when the Calcination Drum was implemented it was found that some problems were encountered. The main aim of this project is to solve the problems related to guide ring and support roller shaft of Calcination Drum. The shaft is redesigned by changing its material and considering all forces acting on it. Similarly the modified fabrication process is also suggested for guide ring. In this paper Analysis of roller shaft, roller and Calcination drum is carried out and the stress and deformation is found out in static and dynamic condition. For theoretical calculations of shaft the standard data is taken from design data book and for guide ring Hertz contact stress theory is used

    Smart Approach for Public Transport

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    This paper is to provide public a Smart Assistance in Public Transport System. The paper is to be implemented for public bus (for PMTs in Pune). It has the entire smart assistance system required for public security and safety. The smart system includes safety form rash driving as well. It has accident detection and monitoring facility. It also has user friendly application for user to track bus on smart their phones. The smart system designed has both online (GPS) and offline (GSM) for user friendly service. It allows user to save its time by acknowledging no. of persons present in the bus as well as no. of seats available in the bus along with the current and next stop acknowledgment with its arrival timings. It also has ramp facility for handicap people. The system also many additions feature to make public transport system an intelligent and easy to use system so that public can take smart advantage of it. The system is specially designed for Smart Cities as it\u27s the recent development plan

    A Survey on Review Based Recommendation System

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    The advances in internet technology have resulted in the generation of huge amount of data called as Big Data. Recommendation system is a widely used technique for the filtering the huge amount of data and providing recommendations to users according to their interest. Without taking previous user interest into consideration, the traditional recommender system does not provide efficient solutions to the users. In this paper, we introduce recommender system to solve the above-described problems. The proposed recommender system will take into consideration previous user’s interest and active user interest and by calculating similarity it will to provide recommendations to active user

    Quantum matchgate computations and linear threshold gates

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    The theory of matchgates is of interest in various areas in physics and computer science. Matchgates occur in e.g. the study of fermions and spin chains, in the theory of holographic algorithms and in several recent works in quantum computation. In this paper we completely characterize the class of boolean functions computable by unitary two-qubit matchgate circuits with some probability of success. We show that this class precisely coincides with that of the linear threshold gates. The latter is a fundamental family which appears in several fields, such as the study of neural networks. Using the above characterization, we further show that the power of matchgate circuits is surprisingly trivial in those cases where the computation is to succeed with high probability. In particular, the only functions that are matchgate-computable with success probability greater than 3/4 are functions depending on only a single bit of the input

    A Survey on Big Data, Hadoop and it’s Ecosystem

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    Now days, The 21st century is emphasized by a rapid and enormous change in the field of information technology. It is a non-separable part of our daily life and of multiple other industries like education, genetics, entertainment, science & technology, business etc. In this information age, a vast amount of data generation takes place. This vast amount of data is referred as Big Data. There is a number of challenges present in the Big Data such as capturing data, data analysis, searching of data, sharing of data, filtering of data etc. Today Big Data is applied in various fields like shopping websites such as Amazon, Flipkart, Social networking sites such as Twitter, Facebook, and so on. It is reviewed from some literature that, the Big data tends to use different analysis methods, like predictive analysis, user analysis etc. This paper represents the fact that, Big Data required an open source technology for operating and storing huge amount of data. This paper greatly emphasizes on Apache Hadoop, which has become dominant due to its applicability for processing of big data.Hadoop supports thousands of terabytes of data. Hadoop framework facilitates the analysis of big data and its processing methodologies as well as the structure of an ecosystem
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