2,954 research outputs found
From the Sakai-Sugimoto model to the generalized Skyrme model
No full textWe derive the generalized Skyrme model as a low-energy effective model of the Sakai-Sugimoto model. The novelty with the past is the presence of the sextic term equal to the topological charge squared. This term appears when the ω meson, and the tower of states on top of it, are integrated out. We claim that, in the small 't Hooft coupling limit, the instanton is well described by a Skyrmion arising from the low energy effective Lagrangian of the Sakai-Sugimoto model. The sextic term plays a dominant role in this limit. Moreover, when a pion mass term is added, we recover the BPS Skyrme model in the small 't Hooft coupling limit
Who is the author of the 1876 Stefano manuscript?
No full textFor over one hundred years the Stefano manuscript was a private document in the possession of the Baccich family and descendants. It told a story of the 1875 Stefano shipwreck as narrated by the shipwreck survivor and the founding family patriarch Miho Baccich. In these circumstances the question of authorship of the manuscript was immaterial and did not arise as an issue. However, with the publication of the manuscript the author‟s name, or names, need to be formally attributed to it. It turns out that this is not such a clear-cut matter.
As we shall see, all informed sources attributed the authorship, and the ownership, of the manuscript to Miho Baccich. But the manuscript itself was written by Canon Stjepan Skurla – a priest from Miho‟s hometown of Dubrovnik. The question then arises: should Skurla also be considered as an author of the manuscript, or, even as the sole author (as some would have it)
Useful ToPIC: Self-tuning strategies to enhance Latent Dirichlet Allocation
No full textToPIC (Tuning of Parameters for Inference of Concepts) is a distributed self-tuning engine whose aim is to cluster collections of textual data into correlated groups of documents through a topic modeling methodology (i.e., LDA). ToPIC includes automatic strategies to relieve the end-user of the burden of selecting proper values for the overall analytics process. ToPIC's current implementation runs on Apache Spark, a state-of-the-art distributed computing framework. As a case study, ToPIC has been validated on three real collections of textual documents characterized by different distributions. The experimental results show the effectiveness and efficiency of the proposed solution in analyzing collections of documents without tuning algorithm parameters and in discovering cohesive and well-separated groups of documents with a similar topic
Modelling noise propagation generated by forest operations: a case study in Southern Italy
No full textNoise is defined as an undesired sound that constitutes an unwarranted disturbance potentiality modifying animal behaviour or normal functioning. Forest operations commonly involve the use of equipment and machines that can produce noise and be a potential permanent or temporary disturbance for the wildlife. This study simulates noise propagation in a natural area generated during coppice stand harvesting by direct field noise measurements and the application of a specific GIS model. Two working phases were investigated: felling and yarding operations. Two potential systems were analyzed for the yarding operations: a) yarding by mobile cable yarder and b) skidding by tractor with a three point log grapple. The results are reported in terms of excess noise area for the third-octave bandwidths with the centre in 500 Hz, 1000 Hz and 2000 Hz. Felling by chainsaws presented the largest area where noise exceeds the ambient natural noise, while in the case of yarding, mobile cable yarding operations presented a smaller area of excess noise than skidding by tractor
Using high-frequency accelerometer to detect machine tilt
No full textThe use of full-mechanized harvesting systems is limited by terrain factors, such as very steep slopes and roughness terrain. Focusing on salvage logging conditions, forest operations are characterized by high costs and reduced productivity, as well as in terms of safety. This work aims to identify and compare the relation between the machine tilt and ground slope and the effect in different harvesters and forwarders, based on the technology and type of machine. In particular, the machines involved in this study are a harvester and forwarder working in the specific condition of salvage logging in windthrow areas. High-frequency 3-axis accelerometers and a GNSS sensor were used to monitoring in continuous tilt and motion of the machines. From the position detected by the GNSS sensor, the ground slope was obtained. The results report that the correlation between the machine tilt and ground slope depends on the type of the machine and technology. The high-frequency 3-axis accelerometer results are affordable to detect an accurate machine tilt showing the possibility to use the combination of different low-cost sensors to analyze the operation condition of forest machines in complex terrain
Fashion Culture: Power In Fashion with Stefano Tonchi and Grazia d'Annunzio
No full textStefano Tonchi, global chief creative officer for L’Officiel Group, and Grazia d’Annunzio, former deputy director of Vogue Italia, discuss the power of military uniforms and their influence on high fashion. Tonchi is co-author of the book "Uniform: Order and Disorder.
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