Popularity Prediction

With the rise in popularity of the Internet, data describing unique types of items has been collected into easy to access sources. Using this newly acquired data, is it possible to predict if an item will become a bestseller while another fade away with time? Popularity prediction is a problem that has attracted a great deal of research recently, and for good reason. The ability to predict an items future rise to popularity or fall to obscurity is a possibly priceless skill and sought out in many different industries such as sales, investments, and marketing. This report enumerates and analyzes a number of factors assumed to be an indicator of popularity. Additionally, we propose a number of popularity prediction methods, and evaluate using a cohost of evaluation metrics, and state of the art baselines. Our findings show promising potential for popularity prediction, based on a combination of structural and temporal properties indicative of popularity. The key proposed metrics include a measure of similarity between two items, and various definitions of popularity evolving with time. Experiments on a large scale real dataset from Yelp allow us to demonstrate the performance of our methods on predicting the popularity of businesses. We believe the methods described below can be extended to be used for diverse types of data

Fracture mechanics of pseudoelastic NiTi alloys: review of the research activities carried out at University of Calabria

This paper reports a brief review of the research activities on fracture mechanics of nickel-titaniumbased shape memory alloys carried out at University of Calabria. In fact, this class of metallic alloys show aunusual fracture response due to the reversible stress-induced and thermally phase transition mechanismsoccurring in the crack tip region as a consequence of the highly localized stresses. The paper illustrates the mainresults concerning numerical, analytical and experimental research activities carried out by using commercialNiTi based pseudoelastic alloys. Furthermore, the effect of several thermo-mechanical loading conditions onthe fracture properties of NiTi alloys are illustrated

Architecture of the cloud, virtualization takes command : learning from black boxes, data centers and an architecture of the conditioned environment

Thesis (S.M. in History, Theory and Criticism of Art and Architecture)--Massachusetts Institute of Technology, Dept. of Architecture, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 127-128).A single manageable architecture of the Cloud has been one of the most important social and technical changes of the 21st century. Cloud computing, our newest public utility is an attempt to confront and control cultural risk, it has rendered the environment of our exchanges calculable, manageable, seemingly predictable, and most importantly as a new form of capital. Cloud computing in its most basic terms is the system of virtualization of data storage and program access into an instantaneous service utility. The transformation of computing into a service industry is one of the key changes of the Information Age, and its logic is tied to the highly guarded mechanisms of a black box, an architecture machine, or more commonly known as the data center. In 2008, on a day with without the usual fanfare or barrage of academic manifestoes, grand claims of paradigm shifts, virtualization quietly took command. A seemingly simple moment where a cloud, the Cloud, emerged as a new form of managerial space that tied a large system of users to the hidden mechanisms of large scaled factories of information, a network of data centers. The project positions the Cloud and the data center into the architectural discourse, both historically and materially, through an analysis of its relationship to an emergent digital sublime and how it is managed, controlled and propelled through the obscure typologies of its architecture and images. The study of the Cloud and the data center through the notion of the sublime, and the organizational structures of typology we can more critically assess architecture's relationship to this new phase of the Information Age.by Antonio Furgiuele.S.M.in History, Theory and Criticism of Art and Architectur

Fatigue Crack Growth in Austenitic and Martensitic NiTi: Modeling and Experiments

AbstractFatigue crack growth of austenitic and martensitic NiTi shape memory alloys was analyzed, with the purpose of capturing the effects of distinct stress-induced transformation mechanics in the two crystal structures. Mode I crack growth experiments were carried out, and near-crack-tip displacements were captured by in-situ digital image correlation (DIC). A special fitting procedure, based on the William's solution, was used to estimate the effective stress intensity factor (SIF). The SIF was also computed by linear elastic fracture mechanics (LEFM) as well as by a special analytical model that takes into account the unique thermomechanical response of SMAs. A significant difference in the crack growth rate for the two alloys was observed, and it has been attributed to dissimilar dissipative phenomena and different crack-tip stress–strain fields, as also directly observed by DIC. Finally, it was shown that the predictions of the analytical method are in good agreement with effective results obtained by DIC, whereas a very large mismatch was observed with LEFM. Therefore, the proposed analytical model can be actually used to analyze fatigue crack propagation in both martensitic and austenitic NiTi

Fracture mechanics of pseudoelastic NiTi alloys: review of the research activities carried out at University of Calabria

This paper reports a brief review of the research activities on fracture mechanics of nickel-titanium based shape memory alloys carried out at University of Calabria. In fact, this class of metallic alloys show a unusual fracture response due to the reversible stress-induced and thermally phase transition mechanisms occurring in the crack tip region as a consequence of the highly localized stresses. The paper illustrates the main results concerning numerical, analytical and experimental research activities carried out by using commercial NiTi based pseudoelastic alloys. Furthermore, the effect of several thermo-mechanical loading conditions on the fracture properties of NiTi alloys are illustrated

multiaxial fatigue behavior of additive manufactured ti 6al 4v under in phase stresses

Abstract The development and application of additive manufacturing (AM) technologies is constantly increasing. However, in many applications, AM parts are subjected to multiaxial loads, arising from operating conditions and/or complex geometries. These make AM components serious candidates for crack initiation and propagation mechanisms. Therefore, a deep understanding of the multiaxial fatigue behavior of AM parts is essential in many applications where durability and reliability are core issues. In this study, multiaxial fatigue of Ti6Al4V thin-walled tubular specimens, made by Selective Laser Melting (SLM) process, was investigated by combined axial-torsional loads. Infrared thermography (IR) was also used to investigate the temperature evolution during fatigue tests. Results highlighted different damage mechanisms and failure modes in the low- and high-cycle fatigue regimes

Multiaxial fatigue behavior of additively manufactured Ti6Al4V alloy: Axial–torsional proportional loads

Additive manufacturing (AM) techniques are under constant development and selective laser melting (SLM) is among the most promising ones. However, widespread use of AM techniques in many industries is limited by the different/unusual mechanical properties of AM metallic parts, with respect to traditionally processed ones, especially when dealing with complex fatigue loading conditions. In fact, crack formation and propagation mechanisms are mainly affected by the development of internal defects, residual stresses, and microstructural changes. This is actually one of the major issues the materials engineering community is facing today. In many applications, AM components are subjected to multiaxial fatigue loads, arising from operating conditions and/or from complex geometries, that unavoidably generate crack initiation and propagation mechanisms. The aim of this study is to investigate the multiaxial fatigue behavior of additively manufactured Ti6Al4V samples, made by SLM. Fatigue tests, combining proportional axial and torsional loads, were performed on thin-walled tubular specimens. Full-field measurement techniques, such as the infrared thermography and digital image correlation, were also used to capture temperature and strain evolutions, at both local scales and global scales. Fatigue results highlighted damage mechanisms, and failure modes are strongly related to the applied stress level

INFLUENZA DELLA SALDATURA LASER SUL COMPORTAMENTO A MEMORIA DI FORMA A DUE VIE DI UNA LEGA NiTi

Nel presente lavoro è riportato lo studio del comportamento funzionale di un giunto saldato in lega NiTi a memoria di forma. In particolare, sono stati analizzati gli effetti della saldatura laser Nd:YAG sul comportamento a memoria di forma a due vie (Two Way Shape Memory Effect, TWSME) di una lega Ni- 51 at.% Ti, attraverso un confronto sistematico con i risultati relativi al materiale non saldato. Il TWSME è stato indotto nel materiale attraverso un opportuna procedura di training, che consiste nella ripetizione di cicli termomeccanici; successivamente, sono stati misurati i cicli di isteresi (temperatura-deformazione) caratteristici del TWSME. Sono stati valutati, inoltre, gli effetti del numero di cicli di training e delle deformazioni plastiche, che si generano nel materiale durante il processo di training, sul comportamento a memoria di forma del materiale. I risultati mostrano come il comportamento funzionale, e in particolare il TWSME, sia parzialmente preservato nel materiale saldato che, comunque, presenta valori di deformazioni plastiche maggiori rispetto al materiale base