Desenvolupament d'un agent intel·ligent dins el marc de la competició TAC SCM

Aquest projecte està emmarcat dins el grup eXiT d’Intel•lig`encia Artificial del Departament d’Electrònica i Automàtica (EIA) de la Universitat de Girona. Pertany a l’àmbit de la Intel•ligència Artificial i, concretament, en l’apartat d’agents intel•ligents. En el nostre cas, tractarem el desenvolupament d’un agent intel•ligent en un entorn determinat, el de la gestió d’una cadena de producció. Amb l’objectiu de proporcionar un marc experimental on provar diferents tecnologies de suport a la gestió de la cadena de producció, la comunitat d’investigadors va proposar una competició internacional: la Trading Agent Competiton (TAC). En aquesta competició existeixen diferents modalitats. En particular, la Swedish Institution of Computer Science (SICS), juntament amb la Carnegie Mellon University de Pittsburg, Minnesotta, van proposar al 2003 un escenari de muntatge de PC’s basat en el proveïment de recursos, l’embalatge de PC’s i les ventes a clients. Aquesta modalitat és coneguda com aTAC-SCM (Supply Chain Management)

Supply Multipliers in Two Regional Economies

This paper focuses on the analysis of the economic impact that sectorial total factor productivity – or valued added - gains have on two regional Spanish economies (Catalonia and Extremadura). In particular it is studied the quantitative effect that each sector’s valued added injections has on household welfare (real disposable income), on the consumption price indices and factor relative prices, on real production (GDP) and on the government and foreign net income. To do that, we introduce the concept of supply multiplier. The analytical approach consists of a computable general equilibrium model, in which it is assumed perfect competition and cleared markets of goods and factors. All the parameters and exogenous variables of the model are calibrated by means of two social accounting matrices, one for each region under study. The results allow identifying those sectors with the greatest multipliers impact on consumer welfare as the key sectors in the regional economies. Keywords: efficiency gains, supply multipliers, key sectors, computable general equilibrium. JEL Classification: C68, R13.

Social capital and cognitive attainment

We review the different meanings that researchers have given to theconcept of social capital, differentiate four types – bridging, bonding,linking, and overheads –, and discuss their different functions as public,club, and common goods.For each form of social capital we distinguish its productivity (acollective characteristic) from the factors that account for individual’sdifferential access to its returns, and propose alternative ways formeasuring each.We show the utility of our theoretical and measuring approach byanalyzing the impact of the each form of social capital on 15 year-oldstudents’ cognitive attainment across OECD countries, using 2006 PISAdata.The results show that students’ cognitive attainments are a direct functionof the richness or productivity of each form of social capital and ofstudents’ degree of access to each.

Sovereign Risk, Anonymous Markets, and the Effects of Globalization

The goal of this paper is to study the e¤ects of globalization on the workings of financial markets. We adopt a "technological" view of globalization, which consists of an exogenous reduction in the cost of shipping goods across di¤erent regions of the world. We model financial markets where agents anonymously trade securities issued by every other agent in the world. In the absence of frictions, we show how globalization creates trade opportunities among residents of different regions of the world, thereby raising welfare. In the presence of sovereign risk, however, there emerge two crucial interactions between trade among residents within a region and trade among residents of di¤erent regions. First, the more residents within a region trade with each other, the more they can trade with residents of other regions. Second, the possibility of trade with residents of other regions sometimes leads a government to not enforce payments by its residents, destroying trade opportunities among residents within the region. The net effect on welfare of this process of creation and destruction of trade opportunities is ambiguous. We argue that there are no policies governments can take to avoid the negative effects of globalization on trade among domestic residents. In a dynamic extension, we analyze how our results are a¤ected by reputational considerations.

Economic Booms, Trade Deficits, and Economic Policy

Many economic booms have been accompanied by real exchange rate appreciations, large trade defcits -which have sometimes persisted after the return to the initial exchange rate parity- and a deteriorating traded sector. Those circumstances have typically raised the question of the de-sirability of some stabilization policy. We show that the dynamics induced by an expected productivity shock in an economy where the capital stock is non-mobile across sectors, match those circumstances. Furthermore, we obtain that credit market imperfections tend to exacerbate trade deficits, and to cause an inefficient capacity reduction in the traded sector. Some stabilization policies are explored.

On Globalization and the Growth of Governments

This paper investigates the relationship between trade openness and the size of government, both theoretically and empirically. We show that openness can increase the size of governments through two channels: (1) a terms of trade externality, whereby trade lowers the domestic cost of taxation and (2) the demand for insurance, whereby trade raises risk and public transfers. We provide a unified framework for studying and testing these two mechanisms. First, we show how their relative strength depends on a key parameter, the elasticity of substitution between domestic and foreign goods. Second, while the terms of trade externality leads to inefficiently large governments, the increase in public spending due to the demand for insurance is optimal. We show that large volumes of trade may result in welfare losses if the terms of trade externality is strong enough while small volumes of trade are always beneficial. Third, we provide new evidence on the positive association between openness and the size of government and test whether it is consistent with the terms of trade externality or the demand for insurance. Our findings suggest that the positive relationship is remarkably robust and that the terms of trade externality may be the driving force behind it, thus raising warnings that globalization may have led to inefficiently large governments.

Employment Protection, International Specialization, and Innovation

We develop a model to analyse the implications of firing costs on incentives for R&D and international specialization. The Key idea is paying the firing cost, the country with a rigid labor market will tend to produce relatively secure goods, at a late stage of their product life cycle. Under international trade, an international product cycle emerges where, roughly, new goods are first produced in the low firing cost country will specialize in 'secondary innovations', that is, improvements in existing goods, while the low firing cost country will more specialize in 'primary innovation', that is, invention of new goods.

Bundling and competition for slots: Sequential pricing

In this paper we study, as in Jeon-Menicucci (2009), competition between sellerswhen each of them sells a portfolio of distinct products to a buyer having limitedslots. This paper considers sequential pricing and complements our main paper (Jeon-Menicucci, 2009) that considers simultaneous pricing.First, Jeon-Menicucci (2009) find that under simultaneous individual pricing, equilibriumoften does not exist and hence the outcome is often inefficient. By contrast,equilibrium always exists under sequential individual pricing and we characterize it inthis paper. We find that each seller faces a trade-off between the number of slots heoccupies and surplus extraction per product, and there is no particular reason thatthis leads to an efficient allocation of slots.Second, Jeon-Menicucci (2009) find that when bundling is allowed, there alwaysexists an efficient equilibrium but inefficient equilibria can also exist due to purebundling (for physical products) or slotting contracts. Under sequential pricing,we find that all equilibria are efficient regardless of whether firms can use slottingcontracts, and both for digital goods and for physical goods. Therefore, sequentialpricing presents an even stronger case for laissez-faire in the matter of bundling thansimultaneous pricing.

Advertising bans

I show that an advertising ban is more likely to increase -- ratherthan decrease -- total consumption when advertising does not bring abouta large expansion of market demand at given prices and when it increasesproduct differentiation (thus allowing firms to command higher prices). Inthis case, the main impact of a ban on advertising is to reduce equilibriumprices and thus increase demand. I argue that this is more likely tohappen in mature industries where consumer goods are ex--ante (i.e.without advertising) similar and advertising is of the `persuasive' type.The ban is the more likely to increase profits of the firms the weakerthe ability of advertising to expand total demand and the less advertisingserves to induce product differentiation.

Bargaining, coalitions and competition

We study a decentralized matching model in a large exchange economy,in which trade takes place through non--cooperative bargaining in coalitionsof finite size. Under essentially the same conditions of core equivalence, we show that the strategic equilibrium outcomes of our model coincide with theWalrasian allocations of the economy. Our method of proof exploits equivalenceresults between the core and Walrasian equilibria. Our model relaxes differentiability and convexity of preferences thereby covering the caseof indivisible goods.

Globalization and risk sharing

We study the effects of globalization on risk sharing and welfare. Like previous literature, weassume that countries cannot commit to repay their debts. Unlike previous literature, we assumethat countries cannot discriminate between domestic and foreign creditors when repaying theirdebts. This creates novel interactions between domestic and international trade in assets. (i)Increases in domestic trade raise the bene.ts of enforcement and facilitate international trade.In fact, in our setup countries can obtain international risk sharing even in the absence of defaultpenalties. (ii) Increases in foreign trade .i.e. globalization.raise the costs of enforcement andhamper domestic trade. As a result, globalization may worsen domestic risk sharing and lowerwelfare. We show how these e¤ects depend on various characteristics of tradable goods andexplore the roles of borrowing limits, debt renegotiations, and trade policy.

Additive utility with intransitive indifference and without independence: A homogeneous case

In the homogeneous case of one type of goods or objects, we prove theexistence of an additive utility function without assuming transitivityof indifference and independence. The representation reveals a positivefactor smaller than 1 that infuences rational choice beyond the utilityfunction and explains departures from these standard axioms of utilitytheory (factor equals to 1).

The skill bias of world trade

Under plausible assumptions about preferences and technology, the model in this papersuggests that the entire volume of world trade matters for wage inequality. Therefore,trade integration, even among identical countries, is likely to increase the skill premium.Further, we argue that empirical evidence of a falling relative price of skill-intensive goods can be reconciled with the fast growth of world trade and that the intersectoral mobility of capital exacerbates the effect of trade on inequality. We provide new empirical evidence in support of our results and a quantitative assessment of the skill bias of world trade.

The effects of a universal child benefit

I study the impact of a universal child benefit on fertility and family well-being. I exploitthe unanticipated introduction of a new, sizeable, unconditional child benefit in Spain in2007, granted to all mothers giving birth on or after July 1, 2007. The regressiondiscontinuity-type design allows for a credible identification of the causal effects. I find thatthe benefit did lead to a significant increase in fertility, as intended, part of it coming froman immediate reduction in abortions. On the unintended side, I find that families whoreceived the benefit did not increase their overall expenditure or their consumption ofdirectly child-related goods and services. Instead, eligible mothers stayed out of the laborforce significantly longer after giving birth, which in turn led to their children spending lesstime in formal child care and more time with their mother during their first year of life. Ialso find that couples who received the benefit were less likely to break up the year afterhaving the child, although this effect was only short-term. Taken together, the resultssuggest that child benefits of this kind may successfully increase fertility, as well asaffecting family well-being through their impact on maternal time at home and familystability.

Schooling supply and the structure of production: Evidence from US States 1950-1990

We find that over the period 1950-1990, US states absorbed increases in the supplyof schooling due to tighter compulsory schooling and child labor laws mostly throughwithin-industry increases in the schooling intensity of production. Shifts in the industrycomposition towards more schooling-intensive industries played a less important role.To try and understand this finding theoretically, we consider a free trade model withtwo goods/industries, two skill types, and many regions that produce a fixed rangeof differentiated varieties of the same goods. We find that a calibrated version ofthe model can account for shifts in schooling supply being mostly absorbed throughwithin-industry increases in the schooling intensity of production even if the elasticityof substitution between varieties is substantially higher than estimates in the literature.