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Sopravvenienze e rimedi nel contratto d'appalto: la previsione del cosiddetto obbligo di rinegoziazione
Get PDFIn this thesis I study how the legal system reacts (or ought to react) to unforeseen circumstances that interfere with the functioning of long term contractual relationships. More precisely, I investigate whether mandatory renegotiation would be an appropriate tool to guarantee the flexibility that long-term relationships require.
Furthermore, after having analyzed the instruments that our legal system offers to preserve long-term contractual relationships, I explore the solutions adopted by other legal systems. This comparative analysis helps to formulate normative proposals to improve the functioning of our legal system
The design of the risk-sensitivity of capital requirements: does it matter for bank business choices?
Get PDFBy employing cross-country variations in the adoption of the Basel I and II capital
Accords, we examine how different designs of the risk-sensitivity of capital requirements
influence bank business choices. We show that the move to the Basel II regime has not
amplified the trends found for the Basel I Accord in the form of a reduction in total
lending growth (asset substitution), and increases in lending risk (cherry picking) and noninterest
income activities (activity substitution). In fact, Basel II has led to a reduction in
bank exposure to non-interest income and, at least in the case of banks opting for the high
risk-sensitive Internal Rating Based (IRB) option within Basel II, decreased lending risk.
Nevertheless, the adoption of the IRB approach has had the negative consequence of
lowering the growth rate of loans to the corporate sector and amplifying its procyclicality
The role of cooperation in the development of inter-Korean relations, 1972-2007
Get PDFThe division of the Korean peninsula is a unique case in the history of world politics and
international relations. Also, it is still one of the main issues for the construction of a
stable security regime in Northeast Asia. Finally, it is above all, the continuation of a
"National Tragedy" that resulted in the loss of independence of the Korean people and the
division of the Korean Nation, during and after Japanese colonial rule.
Over the years, relations between the two Korean states have gone through ups and
downs, often characterized by enmity and hostility. The first event in inter-Korean
relations was in fact the Korean War (1950-53), which had the specific intent of
reunifying the peninsula manu militari. Later, this attitude transformed into a hostile
confrontation, until the establishment of a kind of “strategic rivalry” created space for
timid experiments of cooperation.
The end of the Cold War gave more freedom of action for the players involved, as well as
a window of opportunity to intensify exchanges and cooperation between the two Koreas.
In this context cooperation can be regarded as the key to the resolution of the inter-Korean
dispute. In fact, after the collapse of the Soviet Union, the North Korean regime managed
to resist the crisis, avoid collapse and remain in power. The best chance for an
improvement of the situation came from cooperation projects – in particular economic,
cultural, humanitarian, military and even political– which made possible, in some specific
historical periods, significant openings.
In this dissertation I will start from outlining a theoretical paradigm of cooperation among
states, that will be used to analyse the cooperative interactions that took place on the
Korean peninsula. In particular, I will build a comprehensive model aimed at combining
the different approaches to cooperation in existing literature. Great emphasis will be given
to the strategies of creation of mutual trust in international relations, necessary to ensure
long-term cooperation, and to engagement policies, seen as a constructive tool to begin a
process of cooperation born from a situation of hostility.
Afterwards, I will make a detailed reconstruction of the history of inter-Korean relations,
paying greater attention to the historical phases in which the creation of episodes of
cooperation has been possible. In this way, I will identify which were the conditions, both
domestic and international, that made such developments possible.
Finally, I will subject the cooperative relations on the peninsula to a detailed study
through the theoretical framework outlined in the first part. In this way I will be able to
assess the pre-conditions and causes of cooperation, as well as the results obtained and the
effects on the political, economic and social equilibrium on the peninsula. In the latter
part, particular attention will be given to the case of the construction of the joint industrial
park in Kaesong and to economic cooperation, considered as one of the most promising
possibilities toward building a peace-regime and the national reconciliation process
La riproduzione dei condroitti come elemento chiave per la loro conservazione e gestione nel Mediterraneo centro-occidentale
Get PDFChondrichthyes make up one of the oldest and most ecologically diverse vertebrate lineages: they arose at least 420 million years ago and rapidly radiated out to occupy the upper tiers of aquatic food webs (Compagno, 1990; Kriwet et al., 2008; Dulvy et al., 2013). Today, this group of predators plays important functional roles in the control of coastal and oceanic ecosystems (Stevens et al., 2000; Ferretti et al., 2010; Heithaus et al., 2012). They are an important resource, and constitute a significant fraction of the by-catch, which for decades has been undergoing an increase in mortality that has altered the relative abundance and structure of the their worldwide population. This is mainly due to their K-selected life-history strategy that makes them extremely vulnerable and not very resilient to the high rates of mortality due to fishing (Musick, 1999; Cortés, 2002; Dulvy and Forrest, 2010). The knowledge of the biological parameters related to the reproductive biology (life-history traits) and the state of the populations of these marine organisms are essential to plan proper management of fisheries.
Sardinian seas represent a small biodiversity hotspot in the central western Mediterranean, as well as being an important junction of the two basin sides (West and East). The high richness of chondrichthyan species which inhabit these waters combined with the absence of protection measures, has provided an opportunity to undertake a study on the status of these marine predators, in order to establish a starting point for a correct management, studying biological parameters. This aim was achieved conducting specific analysis on sexual maturity going to deepen aspects on their reproductive strategies.
The results on the abundance trends of demersal cartilaginous fish inhabiting the Sardinian waters, were at first useful to identify the most abundant species for which the information on the reproductive cycle and parameters are scarce or fragmented in the literature (Dipturus oxyrinchus, Etmopterus spinax, Galeus melastomus, Raja brachyura, R. miraletus and Squalus blainville). All these species are included in the IUCN red lists.
The adoption of standardized maturity scales for oviparous and viviparous species, through the observation of macroscopic reproductive systems, supported by histological analysis, were crucial for the correct attribution of maturity stages that allowed to discern the different phases of their life cycle and to identify the main reproductive parameters.
The latter revealed a generalized vulnerability to fish mortality in all studied species. Specifically, skates and sharks shown a very late achievement of sexual maturity, in both sexes, with L50 generally higher than 80% of their maximum size. This feature, compared
with those reported in the Atlantic (~ 75% of the maximum total length, Cortés 2000) suggests that the fishing pressure in our seas is worrying.
The reproductive potential of the species seems to depend closely to the hepatic activity that supports the development of ovaries and testes, and in the two viviparous sharks analyzed (E. spinax and S. blainville), guarantees also the embryos' growth, thanks to the production of specific lipids, during the pregnant phases.
The determination of the breeding season is the key for a proper management. Among the oviparous species studied, D. oxyrinchus and G. melastomus showed an extended reproductive period with one and two peaks respectively during the year. A reproductive cycle limited to well-defined period, however, has characterized the two coastal skates (R. brachyura and R. miraletus). E. spinax and S. blainville displayed a reproductive cycle that consists of two different periods (vitellogenesis and gestation) with a quite extensive gestation ranging from 1.5 to about three years. It is evident that the capture of these species, in particular females, especially during the breeding period, would lead to a slow decline of these populations.
A quite extensive reproductive cycle in the two viviparous sharks was further confirmed by the analysis of the oviducal gland micro-architecture, with a 'long-term storage' of sperms (about two years) in special compartments called Sperm Storage Tubules (SST). This observation would lead to hypothesize a reproductive strategy that would benefit them in survival in deep environments, where the chances of mating are rather scarce, thus increasing the reproductive fitness.
The limited reproductive period encountered in R. miraletus has been validated by a 'short-term storage' of sperm cells in the oviducal gland, with a rather rapid preservation of the same. Instead, D. oxyrinchus, that showed an annual reproductive cycle, appeared to preserve the sperm for a longer period of time (in terms of months).
The over-exploitation of a species can lead to changes density-dependent (Fahy, 1989) and, in some populations, the answer to the excessive fishing effort could be offset by the reduction of the medium maturity sizes (Ellis and Keable , 2008). Considering these aspects, the identification of specific spawning areas and the analysis of time trends on the medium sizes of spawners, highlighted that the west coast of Sardinia is the one with a higher concentration of them. In particular, R. miraletus and G. melastomus sizes seems to be temporally undergoing a decline often beyond the L50. For this reason we proposed specific areas that need protection measures and we indicated the minimum size of capture for each species.
Finally, the analysis conducted on the morphology and morphometry of the most common Rajid species egg capsules, led to the creation of a dichotomous table useful for the specific identification of those found stranded or during fishing operations. This table could allow to obtain information on the spatial and temporal distribution and identify any nursery areas in the Mediterranean.
In conclusion, the overall picture of the reproductive status of the six species investigated in Sardinian waters represents a first step in order to impress management measures in the island and later in the Mediterranean. It is hoped that this information can be used for the creation of appropriate management policies by the competent authorities. Moreover, in the near future, there is a commitment to improve the monitoring, including the development of targeted sampling protracted. Finally, we propose to extend the research to the other chondrichthyan species present in the Sardinian seas to have a more complete picture, so we can safeguard these important predators, because without them, marine ecosystems would be destined to collapse
Caratterizzazione idrogeologica dell'area costiera di Arborea
Get PDFThis work aims to the hydrogeologica l characterization of the Bonifica d i Arborea coastal
area, an interesting site on the hydrogeologica l , geological and also historical and
geographical point of view.
Agricultural practices that rely on the use of fertilizers and cattle manure for enhancing soil
productivity, accompanied by the intensive use of groundwater resources, have made this
area particularly vulnerable to nitrate contamination,and pursuant to the Regional
Government resolution n. 1/12 of 18/01/2005, the Bonifica d i Arborea has been designated
as a Nitrate Vulnerable Zone (ZVN).
The nitrate contamination of the shallow aquifer was studied and very high levels of this
pollutant was founded. These studies revealed that this area is geologically and
stratigraphica l very complicated, then a geological survey has been carried out. Vertical
Electrical Soundings (VES) and statigraphies was used for this purpose, they have been
implemented with ArcGIS10. It allowed to know the domain of the shallow aquifer, and in
particular his bottom, identified with the first clay level. It was studied the hydrodynamics of
the aquifer with Surfer 8, and the issues confirmed the geological survey results. Finally
two geological sections have been drown with Adobe Illustrator Artwork 13.
The vanishing of the log term of the Szego kernel and Tian–Yau–Zelditch expansion
Get PDFThis thesis consists in two results.
In [Z. Lu, G. Tian, The log term of Szego kernel, Duke Math. J. 125, N 2
(2004), 351-387], the authors conjectured that given a Kähler form ω on CPn
in the same cohomology class of the Fubini–Study form ωFS and considering the
hyperplane bundle (L; h) with Ric(h) = ω, if the log–term of the Szego kernel
of the unit disk bundle Dh L vanishes, then there is an automorphism φ :
CPn → CPn such that φω = ωFS.
The first result of this thesis consists in showing a particular family of rotation
invariant forms on CP2 that confirms this conjecture.
In the second part of this thesis we find explicitly the Szego kernel of the
Cartan–Hartogs domain and we show that this non–compact manifold has vanishing
log–term. This result confirms the conjecture of Z. Lu for which if the
coefficients aj of the TYZ expansion of the Kempf distortion function of a n–
dimensional non–compact manifold M vanish for j > n, then the log–term of the
disk bundle associated to M is zero
Multidisciplinary studies of pulsar data and applications to Pulsar Timinig Arrays
Get PDFPulsars are fast-rotating, highly-magnetized neutron stars, visible at radio
wavelenghts as pulsating obje
ts thanks to two beams of emission that are fo
ussed
on the magneti
poles and
o-rotate with the star, the rotational axis of whi
h is
not aligned with the magneti
one. The rotational stability and the possibility of
measuring the time-of-arrival of the "pulses" of emission with an extreme pre
ision
allows to
onstrain the physi
al parameters of these sour
es, and to undertake a
wide number of studies. In this PhD Thesis, we exploit this
hara
teristi
to explore
several aspe
ts of pulsar physi
s, mainly related with the "Pulsar Timing Array"
experiments.
The first aspe
t is pulsar polarization. Pulsars are among the most polarized obje
ts
of the radio sky ever known, however, the origin of pulsar polarization and of the
"modes" of polarization that
hara
terize pulsar emission is still obs
ure. Here we
present a
lassi
polarimetri
study of long-period pulsars dis
overed during the High
Time Resolution Universe survey and a new approa
h to
lassify the
ombination of
the polarized mode, along with a first appli
ation to the data.
The se
ond aspe
t dire
tly
on
erns the Pulsar Timing Array experiments, whose
main goal is a dire
t dete
tion of gravitational waves using pulsars. So far, no
dete
tion has been
laimed. However, given the in
reasing sensitivity of these
experiments, it is extremely important to develop solid sanity
he
ks on the data
to state if a future dete
tion is genuine or not. We present here a study about false
dete
tion indu
ed by
orrelated signals in Pulsar Timing Array experiments, along
with a sample of possible routines to mitigate these effe
ts.
The third aspe
t is the long term de
adal stability of millise
ond pulsar template
profiles in flux, that is one of the hypothesis of the pro
edures to obtain extreme
pre
isions in measuring the pulsar parameters. We study 10 millise
ond pulsars
using the longest and most uniform data set in the world. We also present the
surprising result that one of the sour
es in our sample seems to present a sistemati
profile variation along the years
overed by the data set
Tradizione orale, letteratura e violenza nell'Amazzonia peruviana: l'epoca del "caucho"
Get PDFThe main theme of this thesis concerns the indigenous representation and self-representation of the
historical and socio-economic period known as “Época del Caucho” (Rubber Era), and in particular
the invisibilization of the native point of view.
During the Rubber Era (between the last decades of the XIXth century and the beginning of the
XXth) in the Peruvian Amazonian region a really hard coercive working system was established,
involving and confronting native Amazonian people with western and “mestizos” entrepreneurs.
Violent acts committed against indigenous workers brought to, according to various sources, tens of
thousands of victims but, nevertheless, these facts rarely appear on history books and literature.
The thesis – in addition to an historical review and the examination of some official documents –
analyses some novels centred on this subject, underlining similarities and differences among them
and the emic perspective, which is presented through testimonials of some “caucheros” workers'
descendants and their oral literary creations (like tales and songs).
Oral materials have been collected through interviews realized during field work and they are not
just a cultural resistance operation, but also an effective practice of decolonization, in the way that
they give an account of the unbalanced power relationships and present an alternative way to
understand them
Seismic design of timber structures - A proposal for the revision of Chapter 8 of Eurocode 8
Get PDFSustainability and energy efficiency, together with reductions in construction times and costs are becoming
fundamental issues in the housing policies of most of the European and other International Countries. From
all these point of views, timber building systems represent a winning choice, due to: (i) the capacity of
storing carbon dioxide by displacing it from the atmosphere and reducing energy consumption during the
production, transportation and erection compared to other construction materials, (ii) the good thermal
properties of wood which, together with insulation materials, easily lead to reach excellent rates in the
energy performance of the overall building, and (iii) the great speed of construction due to a completely dry
construction process. These advantages, together with the excellent seismic performance witnessed by
recent research results based on extensive numerical simulations and full-scale tests on multi-storey
buildings, explains the reason why timber systems are becoming more and more popular in the
construction of medium to high rise buildings in different seismic areas of Europe, replacing day by day
other materials like reinforced concrete, masonry or steel buildings.
However this progress and the growing diffusion have not been accompanied by a corresponding update of
the provisions to be used in the seismic design, which for the case of timber buildings are included within
Section 8 of Eurocode 8. This chapter was published in 2004 and is very short and incomplete in many parts,
especially when considering design provisions for modern construction systems nowadays widely used, thus
causing real difficulties to structural engineers who have to apply these rules in the seismic design of timber
buildings. Moreover, the differences from other building materials chapters of Eurocode 8 are significant, in
some case substantial, and not always conservative.
The aim of this Ph.D. Thesis is to propose a comprehensive review of the current version of Section 8 of
Eurocode 8 with the modification of most of the existing provisions and the implementation of some new
parts, always from the point of view of a practicing engineer, with the intent to provide clear and simple
rules for the seismic design of timber buildings in seismic regions. In this respect, the research work was
aimed first at analyzing and investigating the evolution of the subsequent versions of this chapter and the
technical-scientific background that led to the drafting of the current version. Subsequently, a detailed
analysis of the different problems which arises in the application of the existing provisions is provided in this
Ph.D. Thesis.
The research was then directed to the analysis of specific problems related to the seismic design of multistorey
timber buildings through linear and non-linear modelling and design applications performed with a
widespread software package among structural engineers like SAP 2000. More specifically, buildings made
with the two most used structural systems for the construction of medium to high-rise timber buildings, i.e. the CLT and the Light-Frame system, were investigated by comparing the analysis results in terms of
dynamic characterization and maximum displacements with those of experimental results conducted on
full-scale buildings.
Additionally a topic of growing interest in the seismic design of multi-storey timber buildings, i.e. the
seismic analysis of hybrid buildings with different lateral load resisting systems, was investigated for a
specific application, i.e. the seismic design of multi-storey buildings with mixed CLT/Light Frame shear walls.
This study was carried out through non-linear dynamic analysis conducted on a case-study four-storey
building with different combinations of CLT and Light-Frame shear walls at each level conducted in order to
establish the value of the seismic behaviour factor to be used in the seismic design. The analysis were
conducted with DRAIN-3DX, a program for inelastic analysis of structures developed at the University of
Berkeley, California, implemented with a numerical model developed at the University of Florence in order
to study the non-linear behaviour of mechanical joints and shear walls in timber structures. The existing
model has been further implemented with new features like strength and stiffness degradation in order to
have a more precise reproduction of the actual non-linear behaviour under seismic excitations.
Finally the last part of the Thesis focuses on a proposal of Background Document for the drafting of a new
version of Chapter 8 of Eurocode 8 with, according to the format of other material chapters of Eurocode 8,
new provisions for the seismic design of existing and new structural systems not covered by the current
version. Furthermore, capacity based design rules are implemented and new values of the over-strength
factors and behavior factors to be used in the seismic design according to the different ductility classes
currently proposed by Eurocode 8 are provided. Some changes related to the ductility rules for dissipative
zones and partial safety factors for material properties to be adopted in the design according to the
dissipative and non-dissipative behaviour are also given. New provisions regarding the design of buildings
with different lateral load resisting systems, the different analysis methods to be adopted in the seismic
design and inter-storey drift-limits are proposed. A code proposal for the evaluation of the behaviour factor
q of mixed CLT/Light-Frame buildings is finally proposed.
The research work conducted and the changes of the code provisions proposed within this Ph.D. Thesis
could be a sound basis for the next revision of the chapter for timber buildings of Eurocode 8. Further
research is nevertheless needed in order to provide more detailed provisions about (i) non-linear static and
dynamic analysis methods in order to foster their use in seismic design, (ii) the use of displacement-based
design as an alternative to the force-based procedure, (iii) the seismic design of innovative low-damage
structural systems and passive base isolation systems for timber buildings, and (iv) design provisions for the retrofitting of existing timber buildings for the next generation of Eurocodes
State estimation in electrical distribution systems
Get PDFThe changes occurring in electrical systems, due to technical and economic reasons, and the requirements of a reliable and efficient delivery of the power supply to the customers demand a smarter management of the current grids at all the levels. In particular, the distribution level, until now managed without a detailed monitoring of its operating conditions, requires significant reinforcements, in terms of both measurement infrastructure and control functionalities, to deal with the changes in a t. In this context, Distribution System State Estimation tools play a key role, sin e they allow the estimation of the operating conditions of the distribution grid, representing the essential link between the measurements gathered from the field and the control functions envisaged in future Distribution Management Systems. In this thesis, the focus has been on the development of appropriate procedures to accurately perform DSSE. Several goals have been pursued. First of all, a DSSE algorithm specifically on conceived for the distribution systems and tailored to the features of these networks has been designed. The proposed estimator allows the proper processing of all the types of measurement, in luding both conventional measurements and new generation synchrophasors provided by Phasor Measurement Units. Particular attention has been paid to the measurement model to be used within the DSSE algorithm, since its implementation an strongly a e t the a ura y a hiev- able in the estimation results. Moreover, a simple method to handle the equality constraints, well suited to the proposed estimator, has been presented to improve its computational efficency. The proposed estimator has been riti ally analyzed and compared to other approaches available in the literature, in order to highlight strengths and weaknesses of the on eived solution. In the second part of the thesis, the problem of DSSE has been analyzed from a wider perspective, aiming at highlighting the impact of different measurement as- pe ts on the estimation results. The impact of measurement type and placement on the estimation a ura y of the different electrical quantities has been deeply investigated, supporting the empiric cal results through a detailed mathematical analysis. Such study an provide important guidelines for the choice of the measurement infrastructure to be deployed in future distribution systems in order to a achieve spe i a ura y targets for the estimation of the different electrical quantities. The possibility to enhan e the estimation a ura y by properly considering the measurement correlations has also been investigated. Developed analysis shows that different sources of correlation an exist in the measurements used as input to the DSSE algorithm. Performed simulations prove that the in lusion of these orrelations in the DSSE model an lead to significant benefits on the estimation a ura y. Finally, a possible de entralized multi-area ar hite ture, designed to handle large distribution networks, has been proposed. Su h a solution has been on eived duly taking into a ount the opposite requirements of a ura y, computational e ien y and low communication costs desirable in realistic scenarios. Even in this case, particular attention has been fo used on the proper modeling of the measurements in order to a hieve estimation results as a urate as possible. To this purpose, a mathematical analysis has been developed to assess the correlations arising in the proposed multi-area approach. Test results on rm the validity of the developed analysis and, above all, prove the importance of a proper consideration of all the measurement aspects for enhacing the a ura y of the estimations. In conclusion, in this thesis, the problem of state estimation in future distribution system has been deeply analyzed, focusing in particular on the issues related to the measurement modeling and processing. The analysis and the results presented in this thesis shows how the achievement of a really smart management and control of future distribution grids (as expected in the Smart Grid scenario) is strictly dependent on the smart deployment, processing and management of the measurements in the network