Search results for "Constructive"
showing 10 items of 301 documents
Tree Structured Self-Organizing Maps
1999
Publisher Summary This chapter provides an overview of the tree structured self-organizing maps (TS-SOM). It was originally intended as a fast implementation of the self-organizing map (SOM). The chapter explains that TS-SOM is a constructive smoother for a class of dimension reduction problems. There is a well known relation between self-organizing maps and principal curves. Unfortunately in most presentations it is derived by simple reasoning, avoiding the mathematical statement of the problem, which is essential to understand how efficient SOM implementations can be constructed. In this chapter, SOM is derived as a numerical solution of a generic model in a continuous domain, which diffe…
Some Generalizations of a Simion Schmidt Bijection
2007
In 1985, Simion and Schmidt gave a constructive bijection φ from the set of all length (n-1) binary strings having no two consecutive 1s to the set of all length n permutations avoiding all patterns in {123,132,213}. In this paper, we generalize φ to an injective function from {0,1}n-1 to the set Sn of all length n permutations and derive from it four bijections φ : P →Q where P⊆{0,1}n-1 and Q ⊂ Sn. The domains are sets of restricted binary strings and the codomains are sets of pattern-avoiding permutations. As a particular case we retrieve the original Simion–Schmidt bijection. We also show that the bijections obtained are actually combinatorial isomorphisms, i.e. closeness-preserving bije…
Aristocratic palaces in the XVIII century in Palermo : The construction site of Merendino-Costantino palace
2015
Palermitan XVIII-century palaces constitute a proper housing typology aimed to reach the highest standards of artistic quality and representativeness. Supported by unlimited financial resources,aristocrats commissioned to famous architects the design and the direction of their construction-sites; nevertheless, technologies were essential and often influenced by an instance of economy with the most effective exploitation of local resources. This work focuses on the constructive specificities of the Palermitan palaces, with reference to the construction history of the Merendino-Costantino Palace, one of the most representative of the historical centre. Its history defines a repertory of const…
The dammuso: constructive characters of the traditional stone buildings of the isle of Pantelleria (Sicily)
2019
Pantelleria, a volcanic island between Tunisia and Sicily, is characterized by a highly windy territory constantly hit by the sun. This harsh environment forced the inhabitants to build in an extremely effective way against the natural elements. This paper investigates constructive technologies, local materials, and phases of construction of the traditional rural houses, the dammuso, a Sicilian word meaning “vaulted-building”. It is a traditional passive cooling building characterized by a cubical shape covered by a vaulted-roof. This typology can be found almost everywhere in the isle, both old and pretty new, as the only one permitted. The minimum configuration unit is a cube made of bear…
The ‘false vaults’ in the architecture of Sicily
2015
Between the end of the 17th century and the first decades of the 18th, Sicily was struck by several violent earthquakes. The total and partial collapse of monumental buildings produced a global debate involving various aspects of construction practice. One of the central topics of discussion was the construction of domes and large vaulted structures. Some architects studied the possibility of using so-called ‘false vaults’, a kind of lightweight structure created with a wooden frame, reed mats, and plaster. The technique was probably known by the 16th century and was used in a few major monuments, such as the dome of the Palermo Cathedral, in the mid-17th century. It was only after the Eart…
La ricostruzione dell'abside in alcuni esempi della seconda metà del XVI secolo a Palermo
2015
Il contributo ha l’obiettivo di studiare alcuni casi di ricostruzione dell’abside eseguiti in edifici chiesastici palermitani nella seconda metà del XVI secolo. Si tratta delle chiese di San Sebastiano, San Francesco d’Assisi e San Martino delle Scale (all’interno dell’omonima abbazia), in cui, nella seconda metà del Cinquecento, per motivi liturgici, l’abside originaria viene “trasformata”, in un’abside “piatta”, al fine di potervi inserire il Coro ligneo. Il nuovo posizionamento del Coro, in conseguenza della Riforma tridentina - problematica centrale nell’Europa di età moderna – suscita, anche in questi casi palermitani, dibattiti e controversie. Il cambiamento della forma dell’abside de…
Shopping malls and neoliberal trends in Southern European cities: post-metropolitan challenges for urban planning policy
2016
Whilst shopping malls have been explored at length by critical urban studies, there has been little exploration of their role in restructuring the practice of urban and spatial planning. This article uses the shopping mall as an object of study in the light of the neoliberal trends and post-metropolisation in Southern Europe, with the aim of exploring challenges for urban governance and planning practice and with a focus on the role of the ongoing economic crisis. A threefold exploratory framework – the ‘lost-in-time scenario’, the ‘messianic mall model’ and the ‘(im)mature planning explanation’ – is used to make sense of the local versions of shopping mall development in Lisbon (Portugal) …
Interventi su volte sottili di mattoni in foglio in Sicilia (Intervention on tiled vaults in Sicily)
2016
Recenti studi hanno confermato come la diffusione nella Sicilia occidentale delle volte sottili di mattoni in foglio (“realine”) sia avvenuta in maniera estesa dalla seconda metà del secolo XVIII ai primi decenni del Novecento, sia negli orizzontamenti e nelle scale dell'edilizia corrente, che con funzione portante e di soffittatura nelle architetture nobiliari. Per finalità di studio o professionali se ne sono analizzati i caratteri costruttivi, le costanti e le variabili, con verifiche su strutture che hanno superato indenni le prove del tempo. In laboratorio o nei cantieri sono state effettuate sperimentazioni accademiche ed interventi di recupero, con ricostruzioni parziali o totali e i…
Timbrel vaults in Sicily. Constructive techniques and intervention methodologies
2017
Tra le tante tipologie di volte riscontrate sul territorio siciliano finalizzate a coniugare economia e leggerezza senza perdere in sicurezza, vengono in questo studio analizzate quelle costituite da due, tre o quattro fogli di mattoni sottili uniti con gesso (volte realine secondo la definizione locale). Non si hanno notizie certe sull’origine di queste volte che, probabilmente introdotte dall’area iberica in Sicilia nella prima metà del XVIII secolo, evidenziano come un sistema costruttivo importato da aree geografiche spesso molto distanti possa essere reinterpretato in funzione dei materiali disponibili e della cultura edilizia locale. Ciò ha in più occasioni determinato soluzioni origi…
Navigation accuracy after automatic- and hybrid-surface registration in sinus and skull base surgery.
2016
Objective Computer-aided-surgery in ENT surgery is mainly used for sinus surgery but navigation accuracy still reaches its limits for skull base procedures. Knowledge of navigation accuracy in distinct anatomical regions is therefore mandatory. This study examined whether navigation accuracy can be improved in specific anatomical localizations by using hybrid registration technique. Study design Experimental phantom study. Setting Operating room. Subjects and methods The gold standard of screw registration was compared with automatic LED-mask-registration alone, and in combination with additional surface matching. 3D-printer-based skull models with individual fabricated silicone skin were u…