Suchergebnisse

Starting from the pioneering papers by Charnes, Cooper and Rhodes (CCR model) and Banker, Charnes and Cooper (BCC model), a large number of papers concerning Data Envelopment Analysis (DEA) with outputs uncertainty appeared in the literature. In particular, chance-constrained programming is the most used technique to include noise variations in data and to solve data envelopment analysis problems with uncertainty in data. Chance-constrained programming admits random data variations and permits constraint violations up to specified probability limits, allowing linear deterministic equivalent formulations in case a normal distribution of the data uncertainty is assumed. The standard DEA models rely on the assumption that inputs are minimized and outputs are maximized. However, both desirable and undesirable (e.g., pollutants or wastes) output factors may be present. The undesirable and desirable outputs should be treated differently when we evaluate the production performance: if inefficiency exists in the production, the undesirable pollutants should be reduced to improve efficiency. In order to include undesirable factors in DEA models, according to the literature, two different approaches can be used to model undesirable factors: one group of DEA models treats them as inputs, whereas a second group considers them as undesirable outputs. DEA models with undesirable factors are particularly suitable for models where several production inputs and desirable and undesirable outputs are taken into account, in order to provide an eco-efficiency measure. In this Ph.D thesis alternative DEA models, which consider both uncertain and undesirable outputs, are proposed and studied. In particular, in the first part of this thesis two different models with uncertain outputs and deterministic inputs are proposed with the aim to move away the classical chance-constrained method and to obtain a more accurate DMU ranking whatever situation occurs. Specifically speaking, the proposed models remove the hypothesis of normal data distribution and use a scenario generation approach to include data perturbations. For the sake of completeness, these models are compared with two further ones based on an expected value approach, where uncertainty is managed by means of the expected values of random factors both in the objective function and in the constraints. Deeply speaking, the main difference between the two proposed models and the expected value approaches lies in their mathematical formulation. In the new models, based on the scenario generation approach, the constraints concerning efficiency level are expressed for each scenario. On the other hand, in the expected value models the constraints are satisfied in expected value. As a consequence, the models proposed in the thesis result to be more selective in finding a ranking of efficiency, thus becoming useful strategic management tools aimed to determine a restrictive efficiency score ranking. In the second part of this study, we focus on environmental policy and eco-efficiency. Nowadays, one of the most intensively discussed concepts in the international political debate is, in fact, the concept of sustainability and the need for eco-efficient solutions that enable the production of goods and services with less energy and resources and with less waste and emissions (eco-efficiency). In particular, we consider the environmental impact of CO2 in cement and clinker production processes. Cement industry is, in fact, responsible for approximately 5% of the current worldwide CO2 emissions. DEA models can provide an appropriate methodological approach for developing eco-efficiency indicators. A cross-country comparison of the eco-efficiency level of the worldwide cement industry is presented by applying both a data envelopment analysis and a directional distance function approach. These tools result to be particularly suitable for models where several production inputs and desirable and undesirable outputs are taken into account. Strong and weak disposability assumptions are analyzed in order to evaluate the impact of environmental regulations interpreted as the cost of regulation. The few papers appeared in the literature of eco-efficiency in cement production analyze the emission performance trends only from an interstate point of view. In this thesis a worldwide study has been carried on, covering 90% of the world's cement production by means of 21 countries, European (EU) and non-European (non-EU) ones. The obtained results show that the efficiency level mainly depends on decisions to invest in alternative raw materials and alternative fuels, both in the case of regulated countries and in the case of voluntary emission-trading schemes. This study highlights, both at national and international levels, the possibility of reducing CO2 emissions and expanding cement production. The use of alternative raw materials, alternative fuels and the possibility of producing blended cements, which require less energy consumption and reduce pollutant emissions, seem to be appropriate means. Environmental regulations can provide incentives in terms of tax exemption benefits or more restrictive pollutant limits. Finally, we try to answer to the following questions: do undesirable factors modify the efficiency levels of cement industry? Is it reasonable to omit CO2 emissions in evaluating the performances of the cement sector in different countries? In order to answer to these questions, alternative formulations of standard data envelopment analysis model and directional distance function are compared both in presence and in absence of undesirable factors. This analysis shows that the presence of undesirable factors greatly affects efficiency levels. Efficiency levels are influenced by investments in best available technologies and by the utilization of alternative fuels and raw materials in cement and clinker production processes. The original results of this Ph.D. thesis have been collected in the following research papers: • Riccardi R. and R. Toninelli. Data Envelopment Analysis with outputs uncertainty. Journal of Information & Optimization Sciences, to appear. • Riccardi R., Oggioni G. and R. Toninelli. The cement industry: eco-efficiency country comparison using Data Envelopment Analysis. Journal of Statistics & Management Systems, accepted for publication. • Riccardi R., Oggioni G. and R. Toninelli. Eco-efficiency of the world cement industry: A Data Envelopment Analysis. Energy Policy, Vol. 39, Issue 5, p. 2842-2854, 2011, available online at: http://dx.doi.org/10.1016/j.enpol.2011.02.057 • Riccardi R., Oggioni G. and R. Toninelli. Evaluating the efficiency of the cement sector in presence of undesirable output: a world based Data Envelopment Analysis. Technical Report n. 344, Department of Statistics and Applied Mathematics, University of Pisa, 2011, submitted to Resource and Energy Economics. The research topic considered in this thesis shows many different lines for future developments. In particular, from a theoretical point of view, starting from the models proposed in Riccardi and Toninelli (2011), we are studying for a bi-objective like DEA formulation where both uncertainty desirable and undesirable factor are taken into account. As regards the applicative aspects, we are also studying and applying bootstrap techniques to manage uncertainty and generate empirical distributions of efficiency scores, in order to capture and analyze the sensitivity of samples with respect to changes in the estimated frontier.

Nowadays the efforts aimed at enhancing the Internal Combustion Engines (ICEs) are mainly focused on the fuel consumption minimization to comply with binding CO2 emission legislation for vehicle homologation. Concerning the Spark-Ignition ICEs, the most widespread path to satisfy the pollutant emission limits is the adoption of a three-way catalyst (TWC) along the exhaust line. As known, this solution poses some issues, such as a low efficiency at cold start or an effectiveness degradation because of aging. In addition, it involves the impossibility to exploit the advantages of lean combustions, since a close to stoichiometric air/fuel mixture is mandatory for efficient TWC operation. For the above reasons, a growing interest towards solutions limiting engine raw emissions is emerging. So future legislation requires new technical measures to increase engine efficiency and reduce pollutant emissions. Here gasoline engines with high specific power have a huge development potential, since, on the one hand, knocking at high Brake Mean Effective Pressure (BMEP) limits thermal efficiency and, on the other hand, high power densities lead to increased thermal loads, which, for component protection reasons, need to be controlled by means of enrichment beyond the stoichiometric air-fuel ratio. This operation leads to increased fuel consumption and to higher pollutant emissions; especially harmful soot particles, hydrocarbons and carbon monoxide are emitted in a higher amount. In addition to known systems, such as exhaust manifolds integrated in the cylinder head for direct cooling of the exhaust gas, extended effective expansion by optimized valve timings (Miller, Atkinson) and external cooled exhaust gas recirculation, also new technologies are being developed for passenger cars. Those technologies primarily aim to widen the lambda one range of the engine in order to maintain the stoichiometric air/fuel ratio throughout the entire engine operating range, which is expected to be required for future Real Driving Emissions (RDE) legislation. The first chapter explains the current situation and future direction of internal combustion engines, with a particular focus on the gasoline engines with high specific power and covers broad regulatory changes in the last year related to tailpipe emissions of criteria pollutants and CO2/fuel economy. Throughout the chapter, a brief overview of internal combustion engines and their future development will be provided so to understand and appreciate why it is still relevant to conduct research in this field, while facilitating the improvement of green technologies in order to achieve a sustainable transportation system. The motivation behind this study and the research direction will also be clarified. Then, a Lamborghini 12-cylinder naturally aspirated spark ignition engine is investigated. The engine is experimentally tested under full and part load operation with two different Air-to-fuel ratio maps. Main performance parameters, in-cylinder pressure cycles and raw pollutant emissions are measured. The engine is schematized in a one-dimensional model (GT-Power™), where "user routines" are employed to simulate turbulence, combustion, knock and pollutant production. 1D model is validated against the experimental data, denoting a good accuracy. The innovative contribution of this section can be hence recognized in the development of a 1D model characterized by a single set of tuning constants allowing for an accurate reproduction of the combustion process in all the engine configurations. As better explained in the following, the combustion model is in fact coupled to a turbulence sub-model, preliminary tuned with reference to 3D-CFD results, in motored operation. This methodology is particularly helpful in the calibration of a VVT engine, where the turbulence levels substantially vary at part load according to the intake/exhaust valve strategies. Combustion and turbulence constants are hence selected through comparisons with few experimental data at full load and 3D results, and then employed at part load and in the optimization process, as well. The results about the raw emissions put into evidence that the numerical approach predicts the experimental data of carbon monoxide (CO) and nitrogen oxides (NO), but it is not enough advanced to reproduce the hydrocarbon (HC) level, although the variations with the engine operating parameters (speed, load, air/fuel ratio) are captured. The model is employed to study the water injection impact to draw the variation trend of the exhaust temperature, performance and the pollutant emissions changing the engine hardware, rather than to predict their absolute levels. The combustion speed takes into account the water presence with a refined correlation of laminar flame velocity and the knock model gives the possibility to set the best spark advance. The water evaporation reduces the in-cylinder temperature and, as a consequence the knock level, is lower. The computed HC, CO and NO maps have been embedded in a vehicle simulation to estimate the impact of the analysed technical solutions on a RDE cycle suggested by Lamborghini. In this way, with a fully numerical approach, a new hardware is analysed and its impact in term of pollutions level is verified on a realistic drive cycle that the new regulations seems to impose. In this way, a new approach to design the future high performance engines has been individuated and the impact of the new regulations can be seen before experimental tests, reducing the time to market and the economic effort. Then, the difference between the engine out emission level and the limit that the regulation imposes can help also to design the after-treatment system. Summarizing, the presented numerical approach showed the potential to predict, on a physical basis, the combined effects of various techniques on the engine performance. This methodology could represent an effective tool to identify the trade-off between engine complexity and expected improvements, contributing to support and drive the development process of new engine/vehicle.

L'Atlante storico dinamico delle circoscrizioni amministrative della Campania costituisce un modello innovativo di ricostruzione della vicenda storica delle regioni d'Italia, con particolare riferimento alle variazioni di denominazione e territoriali dei comuni e delle province intervenute dall'Unità in poi. A partire da un'ampia ricognizione di fonti normative, bibliografiche, archivistiche e cartografiche, si realizza un G.i.s. contenente basi vettoriali per i confronti tra le partizioni territoriali nelle diverse epoche e aperto allo sviluppo di banche dati relative alle diverse dinamiche storiche che hanno interessato la Campania nell''800 e nel '900. Nel G.i.s. sono inoltre previsti Collegamenti ipertestuali per la visualizzazione della cartografia storica e della documentazione iconografica più significativa. ; The dynamic historical Atlas of the administrative districts of the Campania Region is an innovative model to reconstruct the Italian Regional history, with particular reference to the territorial variations and denomination changes of communes and provinces from the Unification (1861), legislative, bibliographic, archival and cartographic sources, have been used to build a GIS based on vector layers for the comparisons between the territorial partitions in different ages and finalized to the development of data base about historical dynamics that have interested the Campania in 19 and 20th. In this GIS moreover hyperlinks run to visualize historical cartography and the more meaningful iconographic documents.

Dottorao di ricerca in Ecologia forestale ; Le criticità di carattere ambientale e produttivo, che attualmente affliggono il settore agricolo, spingono l'attenzione della ricerca e l'interesse delle Istituzioni verso lo sviluppo dei sistemi agroforestali, in modo da abbinare produzioni erbacee e legnose, contribuendo alla salvaguardia ambientale. Il predominio della monocoltura e l'impatto di pratiche agricole intensive hanno contribuito ad una progressiva e pericolosa semplificazione degli agroecosistemi, con serie ripercussioni ambientali e produttive e con un notevole impoverimento di numerosi scenari rurali tradizionali. In tale contesto, il presente lavoro di dottorato si pone l'obiettivo di analizzare il ruolo dei sistemi agroforestali, moderni (sistemi silvoarabili) e tradizionali, nell'ambito della moderna agricoltura, verificandone l'applicabilità in termini di sostenibilità economica. Lo studio è stato condotto alla luce delle nuove direttive a sostegno dell'Agroselvicoltura (Misura 2.2.2 dei Piani di Sviluppo Rurale 2007/13: Primo impianto di sistemi agroforestali su terreni agricoli) e delle modalità di applicazione del Premio Unico Aziendale (PUA) sulle superfici agricole interessate dalla presenza di piante arboree forestali. La tesi ha interessato tre diversi campi d'indagine, strettamente connessi tra di loro e legati alle strategie incentivanti della Politica Agricola Comunitaria (PAC). La prima parte della ricerca ha riguardato l'analisi del modello silvoarabile del noce da legno. Tali sistemi, in base a precedenti ricerche europee di carattere modellistico, sono stati individuati tra i più remunerativi, abbinando la pregiata produzione del legno di noce alla consociazione con diverse colture agrarie. L'obbiettivo della ricerca è stato quello di completare gli studi sull'uso dell'area basimetrica (G) del noce, indice di modellizzazione e di previsione delle performance produttive delle due componenti, erbacea ed arborea, del sistema. Sono state condotte ricerche in una piantagione sperimentale di noce comune ed ibrido del CNR IBAF di Porano, che dal 1992 studia le interazioni tra noce da legno e diverse colture erbacee (grano, trifoglio e prato naturale). Lo studio ha confermato i benefici produttivi di tale sistema colturale, in grado cioè, di assicurare alti ritmi di accrescimento del noce e garantire una buona resa della coltura erbacea consociata. Riassunto Sulla base dei dati raccolti, sono stati elaborati dei modelli colturali di consociazione, per i quali, attraverso l'uso di G del noce, è possibile stimare, sino alla fine del ciclo di produzione legnosa, le interazioni competitive per la luce tra gli alberi e le colture erbacee consociate. La seconda parte della ricerca, realizzata mediante indagini territoriali GIS e rilievi aerofotogrammetrici, analizza la relazione tra sistemi agroforestali e PAC incentivante, con l'obiettivo di quantificare il decremento del PUA per le piante arboree presenti nei sistemi agroforestali tradizionali. Lo studio, condotto in Veneto, Umbria e Lazio, si è concretizzato nell'analisi sia di seminativi arborati tradizionali sia di sistemi lineari arborei lungo i perimetri parcellari. Nei casi esaminati è stata individuata una consistente riduzione del contributo percepito dall'agricoltore per particella catastale, in relazione alla tara generata dalle piante arboree presenti. Inoltre, la ricerca ha anche rivelato una errata fotointerpretazione degli spazi non eleggibili e occupati dalle piante sparse, in contrasto con quanto indicato dalle direttive AGEA per il calcolo del premio. Gli attuali meccanismi di calcolo del PUA per i sistemi agroforestali possono dunque disincentivare gli agricoltori al mantenimento degli alberi fuori foresta. Le informazioni ottenute sono state, infine, validate attraverso interviste strutturate a dottori agronomi, forestali e periti agrari, alla luce della recente introduzione, in alcune Regioni d'Italia, della misura 2.2.2, finanziamenti per l'impianto di nuovi sistemi agroforestali. Il campione studiato ha confrontato due diversi contesti socio-economici ed agronomici del Nord (Veneto) e del Centro (Umbria), per capire il ruolo svolto dalle associazioni di categoria e dai tecnici professionisti nella promozione e propaganda dell'agroselvicoltura e percepire, attraverso il loro rapporto con le aziende agricole, l'effettivo interesse verso tali sistemi. L'indagine ha messo in evidenza il totale insuccesso della misura 2.2.2, legato ad una sua scarsa divulgazione, alla mancanza di un'adeguata attività di ricerca di supporto e alla bassa attrattività economica dei sistemi agroforestali, fortemente legata ad incertezze e lacune del regolamento sulla modulazione del PUA. In generale emerge l'impellente necessità di una PAC più in grado di valorizzare le potenzialità dell'agroselvicoltura per un nuovo modello di sviluppo rurale, in cui gli alberi fuori foresta possano esplicare le proprie valenze produttive ed ambientali. ; Global environmental and productive emergencies, which are currently affecting the agricultural sector, have focused the research attention and the Institutions interest on the preservation and implementation of Agroforestry systems, for their intrinsic capacity of combing food and wood production with environmental preservation. Intensive agricultural practices, combined with predominant monocropping farming systems, have contributed to the progressive and dangerous simplification of agroecosystems, with serious environmental and productive consequences and with a dramatic impoverishment of many traditional rural scenarios. In this context, the PhD work aims to analyze the role of Agroforestry systems in modern agriculture, verifying their economic sustainability. The study, organized into three research papers, was developed in relation to the two main current regulations of the Common Agricultural Policy (CAP) of the European Union linked with agroforestry: Measure 2.2.2 of the Rural Development Plans 2007/13: first establishment of Agroforestry systems on agricultural land; the Single Farm Payment (SFP), supporting farmers according to their Eligible Agricultural Area (EAA), that might be reduced by scattered trees across farmland. The first part of the study is related to Silvoarable models of walnut for timber production and intercropped with arable crops. According to recent modeling research, walnut Silvoarable models are amongst the most profitable farming systems under temperate conditions of western Europe. The PhD research was conducted in an experimental plantation of CNR-IBAF of Porano, where since 1992 there has been a continuous monitoring of the interaction between trees of common and hybrid walnut with the following crops: wheat, clover and meadow. The objective was to bring to the conclusion the observations on the use of tree basimetric area (G), as an index for estimation of the relative yield of intercrops according to the trees growth. This research has confirmed the benefits of walnut Silvoarable systems, combining high tree growth rates and good intercrops yield. According to the collected data, various Silvoarable models are presented according to the tree growth rates and whose G, up to the harvesting age of the plantation, can be Abstract used for minimizing the competitive interactions for the solar radiation towards the intercrops. The second research part analyzed the relationship between the trees outside forest (TOF) and CAP, quantifying the SFP decrement in traditional agroforestry systems. This study was conducted combing GIS with aerial surveys of rural parcels. It was carried out in the regions of Veneto, Umbria and Lazio, and analyzed traditional agroforestry systems, with TOF in the parcels lined up along the borders, as well scattered across. In the study cases it was found a considerable reduction of the SFP, because TOF canopy reduces the eligible agricultural area; additionally, incorrect photointerpretation, in contrast with the official rules regulating the payment of farmers' grants, further reduces the SFP in agroforestry systems. Therefore, the current relationship between SFP and TOF strongly discourage farmers to the maintenance of these trees in their farmland. In the third part, the above results were validated through structured interviews to agronomists and foresters, the professionals in charge to promote innovative farming systems to agricultural stakeholders. The study sample compared two different socio-economic and agronomic realities of the northern (Veneto) and central (Umbria) Italy. The survey showed the total failure of 2.2.2 measure (First Establishment of novel agroforestry systems), depending on: i) inappropriate extension and research activities; and ii) lack of economic attractiveness of agroforestry systems, strongly linked to uncertainties and gaps in the regulation on the SFP modulation. Overall, the research work have showed that the current CAP is not able to promote the high potentialities of agroforestry systems for sustainable rural development, that would be strongly implemented throughout a judicious management of the environmental and productive benefits of trees outside forest.

Engine development has nowadays to deal with a stringent legislation on the pollutant emissions, and a constant attempt to reduce the fuel consumption, as required from the marketing, the governments and the customers. The engine development is high complicated process and CFD simulations play a significant role. They are used at various stages of the design process with different purposes. The goal of this work is to develop a procedure to simulate the mixture formation and wall impingement in GDI engines. In particular, the work is focused on the air motion in-cylinder, on the injection phase, until the mixture formation before the ignition and the research of a correlation between the wall impingement and soot measurement. The ideal workflow is to consider also combustion simulation to relate soot formation estimation with experimental data of emission. The simulation of combustion in gasoline engines is nowadays still in the research phase, and it is generally not used for the engine design. Although it constitutes an interesting research topic, it requires a computation and experimental effort far beyond the current state of the art in the daily engine development process, and it is not covered in this work. On the other end the experimental procedure to measure liquid film formation in engines during the injection process is highly complicated and require facilities not available for this work. All these limitation from simulation and experiments point of view lead us to the decision of correlating wall wet formation of simulation with PN measurement from experiments. The methodology developed is divided in three main simulation: cold flow simulation, injection simulation and wall wet analysis. In the first part the engine flow is validated focusing the attention on velocity magnitude and turbulent kinetic energy fields. In parallel the injection model is calibrated and validate in the spray box, using as target the experimental spray penetration length and droplets size distribution. Once the first 2 simulation are validate, the injection model is implemented in the engine simulation to evaluate the liquid film formation. If a correlation between the in-cylinder wet surface and soot measurement is found, in the future engine development process will be possible to use CFD to estimate liquid film and from that have a prediction of soot formation. This methodology allows to save time and money that always represents a critical point in the engine development.

This study seeks to understand the effect of institutions on debt sustainability in low- and middle-income countries (LMICs). This is motivated by rising government debt levels due to the COVID-19 pandemic and China's Debt-Trap Diplomacy which has undermined the sovereignty of many LMICs. The study proposed a dynamic debt model which relates the ratio of debt-to-GDP as a function of interest rates, exchange rate, primary budget balance, institutions and a vector of controls such as inflation and foreign currency reserves, whereby the ratio of debt-to-GDP measures debt sustainability and the interest rate measures the cost of debt. It also includes the lag of the ratio of debt-to-GDP to capture the debt dynamics in LMICs. To estimate the model, I used an annual data from the WDI from 2005 to 2018 for a total of 135 countries which gives a total of 1890 observations to estimate the effects of institution on debt sustainability in LMICs. To check the robustness of the effects of institutions on debt sustainability in LMICs, I also used institutional data from the WGI. Moreover, I also make a pre-estimation analysis to understand the nature and distribution of the collected data so as to identify the most appropriate estimation for an accurate and reliable result for statistical inference. The results show that having institutions is not enough to achieve debt sustainability, these institutions must be active in controlling corruption and improving transparency and accountability in the public sector. In the absence of active and strong institutions to ensure transparency in contracts, debt statistics and allocation, public debt is more likely to be embezzled and use for non-productive programs especially during election cycles.

This paper analyze the effect of green energy, carbon dioxide emission, and militarization on green economic development. This study uses Turkey as a research country. Autoregressive Distributed Lags (ARDL) model has been used to examine the time series data of Turkey over the years between 1980 and 2015.

The problem of atmospheric air pollution, caused by the Internal Combustion Engines (ICEs), has never been greater than today. Car manufacturers, driven by more and more stringent legislations, are continuously forced to find proper technical solutions to deal with this challenge, without giving up on the high standards regarding engine performance. In particular, the new emission limit for the CO2 recently set for the 2026, with a target of 80 g/km of CO2 along the WLTC, has never pushed so much the automotive manufacturers in developing innovative and clean solutions to improve the fuel economy of the vehicle fleets. However, how to solve this problem is still an open debate. On the one hand, the complete disappearance in few years of the ICE-based propulsion systems in the automotive sector, replaced by fuel cell and/or Battery Electric Vehicles (BEVs) seems to be expected. On the other hand, several analyses declare that potential benefits of a BEV cannot be easily defined. Indeed, if the CO2 formed during the entire vehicle life cycle is considered, the emissions from the two antagonist vehicles become comparable, to such an extent that ICE-based vehicles could be even better than the "zero-emission" alternatives. As often happen, the truth is somewhere in-between, hence, it should be expected in the years to come rather than a pure electric or ICE-based mobility a scenario characterized by variegated technologies that are best suited to the contest in which they are employed. This means that ICE-based vehicles, HEVs, PHEVs, BEVs or even Fuel Cell based vehicles, will coexist in the market for a long time, pushing car manufactures to overcome the limits related to each technology. On the light of the above concerns, the topic of this research activity is to numerically investigate, through a hierarchical simulation-level approach, innovative SI engines, eventually suitable for hybrid powertrains, with a strongly reduced CO2 impact. To this aim, two different ICEs are analyzed, assessing their CO2 emission along the WLTC. The former is a downsized turbocharged VVA 2-cylinder engine, for a conventional vehicle application, defining the reference for the state of art of ICE-based propulsion system. The latter is an innovative 4-cylinder SI engine, equipped with an active pre-chamber ignition system, which guarantees an ultra-lean operation all over the engine operating range. Here, HEV/PHEV architectures are considered for the vehicle simulation. Additionally, the potential fuel economy as well as CO2 benefits, coming from Connected and Automated Vehicles (CAV), are investigated through a numerical methodology able to benchmark these last on a real world-scenario. The simulation efforts carried out to assess the previous objectives is mainly effected in a 0D/1D modelling environment, where the whole engine system is schematized through a network of 1D pipes and 0D cylinders, the latter described in term of in-house developed quasi-dimensional models of the in-cylinder phenomena. In particular, the flame propagation in the conventional engine is modeled according to a well-assessed version of the fractal combustion model developed at the University of Naples Federico II. Whereas, for the pre-chamber engine, a dedicated and innovative procedure, still based on the fractal theory, is developed, since, differently from conventional SI ICEs, only a few predictive combustion models were available in the current literature at the beginning of this activity. The reliability of the overall simulation models is checked for both the engines through the comparisons with 3D or experimental data, using a unique engine-dependent set of tuning constants. Once verified that the physics included in the model is accurate enough to guarantee a good agreement, the model is utilized as a predictive tool for deriving the complete performance maps of both a conventional and a pre-chamber engine. To this aim, a Rule-Based (RB) calibration strategy is also implemented in both the models to identify the optimal values of each control variable in whole operating plane. Of course, the reliability of the RB calibration is demonstrated, too, through the comparison with the outcomes of a general-purpose optimizer, for both the engine architectures. The RB methodology demonstrates to furnish control parameter close to the optimizer, in a very limited computational time. Finally, the engine maps are embedded in vehicle simulations to quantify the CO2 emission over a WLTC, for many different engine and vehicles architectures. In parallel to the above activities, a dedicated off-line Energy Management Strategy, named ETESS, for the HEV is also developed aiming to minimize the CO2 emission along a prescribed mission. The ETESS is compared with the well-known Pontryagin Minimum Principle (PMP) in terms of management of the control units and vehicle performance outcomes. Although the ETESS can only furnish a sub-optimal solution, the reduced computational time to the respect of the PMP suggests the possibility to implement it for an on-line application, with limited penalization. The results carried out in this research activity show that the ICE-based system can reach 94.81g/km CO2 along the WTLC. However, this value is still far away from the EU target of 80 g/km CO2 of 2026. On the contrary, PHEV architecture combined with a pre-chamber engine, able to achieve a maximum Indicted Thermal Efficiency (ITE) around 50%, attains a CO2 emission equal to 43.0 g/km along the same regulatory driving cycle. Although this impressive result, it has to remark that in the current regulation the CO2 emissions necessary for charging the battery is not included, leading to a not representative enough results of the real condition. On the contrary, the HEV configuration reaches 88.8 g/km CO2, very close to the EU ambitious target, suggesting that the combination of these two technologies could be a suitable solution for the years to come. Additionally, connected and autonomous vehicle, thanks to the possibility to use the look-ahead information from the route can further improve the CO2 reduction of about 15-17%, respect to a vehicle not equipped with this technology.

This paper contributes to the debate on institutions and economic development by assessing the relationship between landownership concentration and education in Post-Unification Italy (1871-1921). Using historical data both at a district- and provincelevel, I nd evidence of a negative eect of land inequality on literacy rates. This result is conrmed when a large set of control variables is included in the analysis. IV estimates using the presence of malaria as a source of exogenous variation rule out further concerns regarding the presence of potential endogeneity. Further evidence is provided once I explore the panel dimension of the dataset. In addition, by analysing the impact on intermediate outputs such as enrolment rates in primary school, child-teacher ratio, school density, child labor and municipality expenditures, this paper provides insights on the mechanism behind this relationship. Land inequality may have adversely aected literacy rates not only by influencing the supply of schooling through the political process, but also through the private demand for education.

In order to protect river water quality, highly affected in urban areas by continuos as intermittent immissions, it is necessary to adopt measures to intercept and treat these polluted flows. In particular during rain events, river water quality is affected by CSOs activation. Built in order to protect the sewer system and the WWTP by increased flows due to heavy rains, CSOs divert excess flows to the receiving water body. On the basis of several scientific papers, and of direct evidences as well, that demonstrate the detrimental effect of CSOs discharges, also the legislative framework moved towards a stream standard point of view. The WFD (EU/69/2000) sets new goals for receiving water quality, and groundwater as well, through an integrated immission/emissions phylosophy, in which emission limits are associated with effluent standards, based on the receiving water characteristics and their specific use. For surface waters the objective is that of a "good" ecological and chemical quality status. A surface water is defined as of good ecological quality if there is only slight departure from the biological community that would be expected in conditions of minimal anthropogenic impact. Each Member State authority is responsible for preparing and implementing a River Basin Management Plan to achieve the good ecological quality, and comply with WFD requirements. In order to cope with WFD targets, and thus to improve urban receiving water quality, a CSOs control strategy need to be implemented. Temporarily storing the overflow (or at least part of it) into tanks and treating it in the WWTP, after the end of the storm, showed good results in reducing total pollutant mass spilled into the receiving river. Italian State Authority, in order to comply with WFD statements, sets general framework, and each Region has to adopt a Water Remediation Plan (PTA, Piano Tutela Acque), setting goals, methods, and terms, to improve river water quality. Emilia Romagna PTA sets 25% reduction up to 2008, and 50% reduction up to 2015 fo total pollutants masses delivered by CSOs spills. In order to plan remediation actions, a deep insight into spills dynamics is thus of great importance. The present thesis tries to understand spills dynamics through a numerical and an experimental approach. A four months monitoring and sampling campaign was set on the Bologna sewer network, and on the Navile Channel, that is the WWTP receiving water , and that receives flows from up to 28 CSOs during rain events. On the other hand, the full model of the sewer network, was build with the commercial software InfoWorks CS. The model was either calibrated with the data from the monitoring and sampling campaign. Through further model simulations interdependencies among masses spilled, rain characteristics and basin characteristics are looked for. The thesis can be seen as a basis for further insighs and for planning remediation actions.

This paper deals with the world income distribution. In the first part of the article we present a simple theoretical model. We consider an economy that is made up of a representative household and where agents are involved in three types of activities: consumption goods production, human capital investment and physical capital accumulation. By embedding the Lucas (1988) model within the neoclassical growth theory, we determine endogenously the allocation of skills between human capital accumulation and consumption goods manufacturing. Population grows at a constant, positive and exogenous rate n and all the sectors are perfectly competitive. The economy under analysis features another peculiarity: the human to physical capital ratio is assumed to be constant in the very long run. This hypothesis is in line with empirical evidence and allows us to characterise a balanced growth path equilibrium where these two forms of capital may grow over time at the same, constant and positive rate. Our main result is that, along the balanced growth path, the equilibrium per-capita income level depends positively, among others, on the physical capital share of income and the level of skills each individual is endowed with. The second part of the paper is devoted to the empirical analysis. We use two data sets. The first one considers cross-section data relative to 162 countries in the year 1999. The second data set, instead, is a panel of 142 countries over the period 1960-1995. Overall, the data seem to confirm the main conclusions of the theoretical model. Indeed, we find that per-capita output depends positively on (different) measures of human capital and the physical capital share of income (as long as one approximates such a variable with the investment to output ratio). Finally, in the third part of the paper we use the estimated model to study in more detail the process of convergence ( -convergence) in per capita incomes across countries over the period 1960-1995. We conclude that: 1) the convergence in per-capita incomes does not seem to be a strong feature of the considered period; 2) in the same period the international differences in human capital accumulation decreased, whereas those in physical capital accumulation increased. As a consequence, our analysis suggests that the reduction of the international gaps in physical capital accumulation would be the key to the convergence in per-capita incomes across countries in the future.

The provision of renewable energy by agriculture – so called agroenergy – is a key element of the Europe 2020 Strategy and has sparked the public and research debates on the bio-based economy. Hot topics involve direct and indirect land use change, as well as the ability of agroenergy to foster or hinder food and energy security. Worldwide research has dealt with those and other issues associated with the sustainability of the diffusion of agroenergy generation systems, but the subject is still open. The agricultural sectors' contribution to the provision of energy is central issue in Horizon 2020 strategies and has shaped the public and research debates on the future of bio economy. The common agricultural policy (CAP) has been one of the main drivers of farmers' behaviour changes and represents the main agricultural policy instrument to address viability of rural areas and maintaining the profitability of the agricultural sector. In addition, the European Commission backs the agricultural knowledge and innovation system (AKIS), being the key to successful implementation of a bioeconomy in the EU. AKIS-specific measures are also included in the rural development policy of the CAP 2014-2020. Then, studying the AKIS is important for policy planning in the EU. Chapter 2 analyses the AKIS behind the adoption of farm biogas in an area of central Italy, thereby describing adopters' and business typologies. The methodology relies on social network analysis of primary data, collected via questionnaire to plant adopters, and focuses on the estimation of three network attributes: cohesion, knowledge co-creation, and brokerage. We highlight three business models: i.e. multifunctional farm, entrepreneurial farm, and Energy Service Company. The latter is the most widespread. Self-education, upstream industry, agronomists, farmer/biogas unions, university, public-funded projects, and public research centres are AKIS' stakeholders, which provide information and know-how. Upstream industry is the most influential node, the one that can help knowledge diffusion across adopters, regardless of their background. Self-accessible resources are the main providers of information at the adoption-decision stage. The networks are centralized on self-education tools, while upstream industry and the Research Centre on Animal Productions is the broker. Policy intervention aimed at improving AKIS in the biogas sector should involve the upstream industry in decision making, while considering the duality self-accessible information vs. physical advisors. To contribute to the ongoing policy debate towards CAP reform, Chapter 3 provides an empirical model to simulate the impact of alternative CAP mechanism on the provision of renewable energy. By applying a dynamic mathematical programming model the paper tests the impact new policy measures design on provision of second-generation of bio fuel crops that represent a relevant option for the Tuscany farmers. Results show that CAP reform positive impacts on the supply of energy crops mainly due to the introduction of greening payments, which allows an enlarging of crops diversification. Model results stress also the income stabilisation effects of energy production introduction at farm level, due to reduction of farm exposure to the market prices fluctuations. Chapter 4 contributes to the ongoing debate on the sustainability of agroenergy. We propose an empirical model to simulate the diffusion of farm biogas installations and estimate a set of indicators covering the economic, environmental, and social dimensions of sustainability at the regional level. Model results show that agroenergy production can help farmers stabilise their income and keep viable rural areas, despite some trade-offs among socio-economic and environmental indicators. Major drawbacks are environmental risks associated with farming intensification.

The building sector represents around 32% of total final energy demand and 40% of primary energy consumption at European level and is thus very energy-intensive. In this context, the Directive 2010/31/EU "Energy Performance of Buildings" (EPBD recast) establishes a comparative methodology framework for the assessment of buildings' energy performance "with a view to achieving cost-optimal levels". The cost optimal analysis leads to a package of energy efficiency measures that minimizes the global cost over a building's lifecycle. Since it is not possible to apply such analysis to each building, a set of reference buildings (RBs) must be defined to represent the national building stock, as previously done but with different targets. It is important to highlight that hospitals are the most energy-intensive type of building, since they require big amounts of energy for air-conditioning in order to maintain an high air quality level also for the working of equipments and diagnostic tools. To reduce hospitals' energy consumptions while satisfying quality standards, new tools are required. Therefore, referring to the legislative framework in force, this PhD thesis illustrates an original methodology to define a hospital reference building (both for new or existing hospitals) and to evaluate, using a multi-objective approach, the optimal energy performance levels related to different refurbishment scenarios. Referring to a fixed location (Naples, 1034 DD), an original methodology to characterize a hospital reference building is illustrated; in more detail two versions of the reference building were characterized, the first one representative of hospitals built between 1991 and 2005 and the second one representative of new buildings. The core of this methodology is the development of a virtual building based on statistical data and, exceptionally, on experts' knowledge and other sources of information. The methodology is organized in different phases: definition of the geometry, subdivision into thermal zones, definition of the architectural envelope, development of the geometric model, systems' characterization, dynamic energy simulation. The analysis of energy performance, using Energy plus, was carried out for both RBs and the primary energy consumptions for all uses are characterized. Referring to different retrofit's scenario an analysis of elements and technologies for the reduction of the energy demand was carried out, with an approach first focused on the detailed study of the single design element and then on the global analysis of the efficacy of "energy efficiency packages" (EEMs). In order to evaluate the optimal EEMs a new methodology was developed for cost-optimal analysis by means of the multi-objective optimization of hospitals energy performance. Finally a dynamic energy analysis of a real hospital case study, representative of the existing stock, was reported in order to compare with the Reference Building' energy performance.

Dottorato di ricerca Tutela dell'Ambiente, salvaguardia e valorizzazione del Paesaggio, come patrimonio collettivo e rilevante interesse dell'etica contemporanea ; Il Protocollo di Kyoto rappresenta il provvedimento più significativo del processo, iniziato nel 1979 con la Prima Conferenza Mondiale sul clima, che ha portato al riconoscimento della responsabilità delle attività umane nel determinare i cambiamenti climatici in atto. Adottato nel 1997, il Protocollo di Kyoto impegna i Paesi firmatari a ridurre, nel corso del primo periodo di impegno (2008-2012), il livello di emissioni globali di gas serra almeno del 5% rispetto al 1990, assunto come anno di riferimento. A partire dal 1997 è iniziato dunque un lungo e complesso processo di definizione di regole internazionali legalmente vincolanti per attuare e verificare le politiche di riduzione delle emissioni di gas serra. Con la recente ratifica da parte della Russia, nell'ottobre 2004, è stato infine raggiunto il quorum dei Paesi necessario per l'entrata in vigore del Trattato che è appunto diventato operativamente attivo dal 16 febbraio 2005. Accanto al contenimento e alla riduzione delle emissioni, il Protocollo di Kyoto prevede una serie di misure inerenti i settori agricolo e forestale, importanti per il ruolo che rivestono nella fissazione del carbonio. Le emissioni e gli assorbimenti risultanti da queste attività potranno essere quindi incluse, secondo precise regole di contabilizzazione, nei bilanci nazionali di gas serra, allo scopo di compensare, nel caso in cui tali bilanci siano positivi, una parte delle emissioni prodotte dall'utilizzo dei combustibili fossili e dalle altre attività umane che hanno un impatto negativo sull'ambiente quali la deforestazione, l'uso intensivo dei suoli, nonché l'utilizzo indiscriminato delle risorse naturali. L'Italia, ratificando il Protocollo di Kyoto con Legge 1 giugno 2002, n. 120, si è assunta l'onere di conseguire, nel corso del primo periodo di impegno, una riduzione del 6,5% delle emissioni rispetto al 1990. Tuttavia, tra il 1990 e il 2006, si è registrato un aumento delle emissioni complessive pari a circa il 10%, pertanto il reale obiettivo che si dovrà affrontare risulterà certamente più impegnativo. Partendo dalla consapevolezza che la realtà climatica è la migliore dimostrazione che il progresso umano non coincide con la creazione di ricchezza economica, questa ricerca illustra le posizioni e le iniziative a livello internazionale, europeo e nazionale relative al problema del riscaldamento climatico. In particolare, il 23 gennaio 2008 la Commissione Europea ha varato un pacchetto di iniziative per contrastare il Cambiamento Climatico determinato dalle attività umane denominato Climate Action-Energy for a Changing World che ha tre obiettivi principali indicati con la sigla 20-20-20 che devono essere raggiunti entro il 2020: incrementare la produzione di energia da fonti rinnovabili del 20%, ridurre di almeno il 20% le emissioni di CO2 in atmosfera e aumentare l'efficienza energetica del 20%. La politica europea su clima e energia è senz'altro la più ambiziosa iniziativa in materia ambientale intrapresa finora dai governi. La ricerca procede cercando di definire l'impatto degli eventuali cambiamenti climatici sul territorio e sugli ecosistemi naturali, onde individuare le opportune politiche per fronteggiare tali impatti. E' ormai noto, infatti, come la questione climatica sia strettamente connessa con il sistema produttivo ed energetico mondiale basato su modelli di consumo e di produzione insostenibili. La consapevolezza che tali modelli di sviluppo, incentrati sullo sfruttamento indiscriminato delle risorse naturali, hanno dei costi insostenibili per gli ecosistemi e le specie che li abitano è diventata negli ultimi decenni un importante fattore di orientamento e sviluppo dell'innovazione. Si è analizzato pertanto il concetto di sostenibilità che deve necessariamente diventare trasversale a tutte le attività di governo, promuovendo una politica economica che privilegi scelte energetiche all'insegna dell'efficienza e dell'utilizzo delle fonti rinnovabili, nonché tecnologie e modelli organizzativi e di consumo improntati alla tutela ambientale. Questa ricerca analizza inoltre il ruolo degli ecosistemi forestali e dei suoli agricoli nelle strategie di mitigazione dei cambiamenti climatici, ruolo che è stato valorizzato dal Protocollo di Kyoto ed è entrato nel sistema di crediti di emissione previsti dal Protocollo stesso. Naturalmente il potenziale contributo delle foreste nello stoccaggio del carbonio richiede una nuova gestione del sistema agro-forestale per massimizzare l'immagazzinamento del carbonio nel suolo e nelle foreste. Secondo quanto previsto dal Protocollo, le strategie di gestione forestale che possono essere usate per raggiungere questo obiettivo si basano su due tipi di approccio. Il primo è di prevenire o ridurre il rilascio di carbonio dagli stock forestali esistenti, attraverso la promozione di una gestione forestale sostenibile che riduce i prelievi di legname e la prevenzione degli incendi boschivi. Il secondo approccio prevede interventi attivi come nuove piantagioni forestali su terreni agricoli o su suoli degradati e il ripopolamento del manto vegetale in foreste danneggiate da incendi e malattie. Restringendo la disamina di tali tematiche al caso Italia, si è esaminato l'avvio degli adempimenti al Protocollo di Kyoto e le azioni da adottare onde ottemperare al medesimo e alle istanze dell'Unione Europea per fronteggiare il Global Warming. Al fine di completare il quadro circa l'attuazione del Protocollo di Kyoto in Italia, nell'ultima parte di questo studio si è effettuata una disamina dei comportamenti regionali sui provvedimenti presi al fine di adempiere agli impegni presi nei confronti del Protocollo di Kyoto e dell'Unione Europea. ; The Kyoto Protocol represents the most significant act of the process began in 1979 on the occasion of the First World Climate Conference, which brought the acknowledgment of the human accountability the ongoing climate change. The Kyoto Protocol was adopted in 1997 and commits the signatory Members to reducing, in the first commitment period 2008-2012, the overall emissions of greenhouse gases by at least 5% below 1990 levels, which is the historical base year. In 1997 started, therefore, a long and convoluted process with the purpose of defining the international rules, which will be legally binding to put in force and verify the policies and measures to reduce the emissions of greenhouse gases. With Russia's ratification in October 2004 the quorum was formed and eventually the Treaty which entered into force on 16th February 2005. The Kyoto Protocol entails not only the reduction and the limitation of greenhouse gas emissions, but also some measures regarding agriculture and forestry, which are important for their role in the carbon capture and storage. The emissions and absorptions coming from these activities could be therefore included, according specific rules of calculation, in greenhouse gases amounts assigned to each Member, to the final intent of balancing, in the case of positive amounts, part of the emissions produced by using fossil fuels and by other human activities with damaging effects on the environment, such as deforestation, intensive use of soils and the indiscriminate use of natural resources. Italy, which ratified the Kyoto Protocol with Law 1st June 2002, n. 120, committed itself to achieve, for the first commitment period, a reduction by 6.5% below 1990 levels of emissions. Nevertheless, between 1990 and 2006, there was an increase of the overall emissions up to 10% and this will imply a more demanding target to face in the future. Being of the opinion that the new climate reality is the best demonstration that the human progress is incompatible with the production of economic wealth, this research will show the international, European and national positions and initiatives regarding the Global Warming problem. Above all, on 23rd January 2008 the European Commission launched a package of initiatives in order to face up to the climate change caused by human activities called Climate Action-Energy for a Change World, which has three main targets indicated with the short form 20-20-20 and which must be achieved by 2020: increasing renewable energy use to 20%, reducing greenhouse gases to at least 20% and increasing energy efficiency to 20%. The European policy about climate and energy is, doubtless, the most striving programme regarding the environmental issue set by governments by now. This research attempts to identify the impact of climate change on the environment and on the natural ecosystems, in order to find the fitting policies. It is a well known fact, that the climate question is strictly related to the world economic and energy production, which is based on unsustainable mass and production models. The acknowledgment that such development models, so closely intertwined with the improper use of natural resources, have unbearable costs for the ecosystem and the living species, has been in the last decades an important tendency and innovation factor. The concept of sustainability is here seen as transversal regarding all governmental activities, which must promote economic policies towards efficient energy options and renewable forms of energy, but also towards an environmental friendly technology and mass models. This research, as well, analyses the role of forests and agriculture soils on the subject of climate change mitigation, role that was enhanced by the Kyoto Protocol and is now in the emission reduction credits system set by the Protocol itself. Logically, the would-be contribution of forests concerning carbon storage will involve a new agriculture and forest system in order to reach the best result with reference to carbon sequestration in soils and forests. According to the Protocol, there are two different kinds of approach, which can be used to reach the target in the forest management strategy. The first one is to prevent or reduce the carbon release from the existing forest stocks through a sustainable forest management, which should minimize forest cut down and prevent forest fires. The second kind of approach implies active actions such as new forest plantations in place of agriculture or spoiled soils and the repopulation of plants in fire -and disease- damaged forests. Reducing the study in relation to such themes to Italy, it has been examined the set off of the Kyoto Protocol implementation and which actions are to be assumed to facilitate the Protocol fulfilment and the motions made by the European Community to face the Global Warming. In the last part of this research, with the intention of completing the account of the Kyoto Protocol to be carried out in Italy, there is an analysis of the different local levels about actions made with the object of achieving the commitments towards The Kyoto Protocol and the European Community.

Housing tenure structures differ considerably across OECD countries. Typically, the share of owner-occupied housing is very high in Southern European countries (Spain, Italy, Greece), while relatively low in Austria, Germany, France, the Netherlands and in some Nordic countries such as Sweden, Finland and Denmark (see Catte et al. [2004]). This share has increased in most OECD countries during last two decades. Italy, Spain, Portugal, the Netherlands and Belgium registered the largest increases from the eighties to the mid of the first decade of the century. In the UK, the homeonwership rate increased steadily up to 2005, then dropped sharply in the last few years. High homeownership rates and their increments have been in part determined by pro-ownership policies implemented throughout most OECD countries. Such policies can take the vest of tax reliefs for mortgage interest payments, exemptions for capital gains taxation applied to residential property, or generous subsidies for low-income families to reduce the costs of homeownership. Although the orientation of several governments, particularly in Europe, has been to promote homeownership, economists have raised several concerns about the consequences of large homeownership shares on the functioning of the labour market. The analysis of the relation between the housing tenure and the labour market dates back to mid-nineties, when Andrew Oswald pinned on high homeownership rates the blame for the high unemployment rates in Europe (Oswald [1996], Oswald [1997], Oswald [1999]). Making use of aggregate data, Oswald found a strong positive statistical association between the two rates at the international and regional level. Thus, his receipt to reduce unemployment was strikingly at odds with the prevailing political wisdom: "We can put Europe back to work . . . by reducing homeownership" (Oswald [1999])1. Oswald identified five mechanisms that drive the positive impact on unemployment. These are mostly related to the idea that the mobility constraints imposed by homeownership introduce frictions in the labour market which harm its efficiency. The first and most important, is a direct effect. Owner occupiers incur higher transaction costs for selling home and moving to a new accommodation, which can be even higher whenever capital gains for houses are taxed and there are no exemptions. The other four mechanisms can be thought as externalities of homeownership. Second, where the rental market is thin, everyone, regardless of the housing tenure, can have difficulties in finding the accommodation close to the job they aspire to, so that efficient job matches are hindered. This is the case even for mobile people who would be happy to move for job reasons, such as young still living in the family-home in a kind of free-rent status. Third, owning the accommodation hampers also job-to-job changes and prolong poor job matches hence harming the whole economic system efficiency. Fourth, owner-occupiers are more likely than renters to lobby for deterring entrepreneurs from investing in their residential area. Fifth, since owners commute much more than renters, and over longer distances, higher homeownership rates in the area lead to higher transport costs and possibly to congestion costs, which make getting to work more costly for everyone and act as a sort of unemployment benefits in increasing the relative attractiveness of not working. Although the argument underlying a positive relationship between homeownership and unemployment originates from macroeconomic evidence, its theoretical foundations are mainly microeconomic and a vast part of the empirical research carried out subsequently has been based on micro data. The typical test of the so-called "Oswald thesis" consists in estimating the homeownership effect on the duration of the unemployment spell or, less often, on the probability to be unemployed. The expected sign is positive, along the main idea that higher mobility costs due to property holding reduce the willingness to accept job offers which require a residential move. Fewer studies, and only recently, have focused on the employment duration, testing whether homeownership can reduce job finding rates also for people already employed. Generally, empirical tests on micro data find no support for the Oswald hypothesis, and in most cases even that homeowners have shorter unemployment spells and lower likelihood to be unemployed, which are exactly counter-Oswald results. However, homeownership seems to increase job stability by hampering job-to-job changes for people already employed. As regards unemployment outcomes, the existing literature has put forward two possible reasons for the falsification of the Oswald hypothesis. The first one looks at the different effect of mobility costs on job search behavior in the local and in the non-local labour market. In fact, homeowners may have higher reservation wages for jobs which require a residential move (nonlocal market), but also lower reservation wages for jobs which do not (local market), so that job finding rates for the latter may be as high as to offset the lower rates for jobs in a distant area. Thus, whether the total job finding rate is lower for homeowners or for renters is just an empirical matter which depends on the magnitude of these two opposite effects. The second explanation points out the need for a refinement in the definition of the residential status. On the one hand, one should distinguish between owners who have to comply with mortgage payments and outright owners, as housing financial commitments can bear higher pressure to return to work or to keep on with the current job. For mortgage-holders, these financial constraints can counteract the effect of the reduced mobility due to ownership. On the other hand, unemployment outcomes can be different also for private and social renters. In fact, below-market rent, long waiting lists, security of tenure and the restricted transferability within social housing, can harm the relative performance of social renters. In this work, we aim at investigating the validity of the "Oswald thesis" taking into account the recent refinements by following both a theoretical and an empirical approach. The focus will be on UK micro data. In particular, we will make use of the two leading UK Surveys, the UK Quarterly Labour Force Survey and the British Household Panel Survey. In the first chapter, we investigate the relation between job search effort of unemployed and housing tenure. We test this relation focusing on the impact of the UK Jobseeker's Allowance reform introduced in the UK in October 1996, whose main aspect was a strengthening of search requirements for eligibility to the unemployment benefit. We revisit a simple model of search in which we introduce moving costs and housing costs to capture the two channels through which the degree of attachment to the accommodation influences search behaviour. Our theory suggests that a tightening in job search requirements, as implied by this reform, raises movements off benefit of non-employed with low search intensity and that this effect should adjust in size depending on the different housing tenure. We draw a dataset from the Labour Force Survey for the period 1995-1997, and by means of a Difference-in-Differences approach we analyze the impact of the reform on the claimant outflow. Average Treatment Effect estimates suggest that the impact of the reform is related to housing tenure. Specifically, renters account for a major portion of claimants who were crowded out of the benefit without finding a job, while the effect on outright owners and mortgagers is lower. Empirical evidence from our dataset clearly confirms that mortgagers search for a job more intensively than renters, as our model predicts. This latter finding is consistent with a higher estimated treatment effect for renters, since a high initial search intensity seems the key to insulate oneself from the impact of the tightening of search requirements. In the second chapter we attempt to reconcile the empirical evidence with the argument in favour of a negative effect of homeownership on exit rates from unemployment. Taking into account some likely reasons for the falsification of the Oswald's thesis, we provide evidence which supports it. At first, in a theoretical model of endogenous job search adapted to distinguish between local and non-local labour markets, we show that homeowners higher moving costs imply unambiguously lower search and lower job finding rates, even though an opposite effect works for jobs which do not require a move. Then, in the empirical analysis we make use of data drawn from the British Household Panel Survey to compare job search intensity measures by housing tenure. In defining the residential status, we distinguish between outright owners and mortgage-holders, and between social and private renters. We find that, controlling for housing costs and for the four-fold tenure definition, non-employed outright owners have definitely a lower attachment to the labour market than renters, and that this effect is even more evident when we compare them to private renters. In the third chapter, we analyse the impact of the housing tenure on labour market outcomes using individual data from the UK labour Force Survey. We estimate both a binary model for the probability to be unemployed and a hazard model for exits out of unemployment. In both models we test for endogeneity of housing tenure. In the binary model, exogeneity is rejected so we perform endogenous multinomial treatment effects estimates. In the hazard model, we find no evidence of unobserved heterogeneity thus estimates are performed assuming exogeneity. Results show that mortgagers have the lowest probability to be unemployed and the highest job finding rates, while social renters exhibit the worst performance. Whether private renters perform better than outright owners is a matter of debate: while we have no evidence in favour of this claim, the evidence in favour of the opposite is only modest.