404 research outputs found
Partial Verification as a Substitute for Money
Recent work shows that we can use partial verification instead of money to
implement truthful mechanisms. In this paper we develop tools to answer the
following question. Given an allocation rule that can be made truthful with
payments, what is the minimal verification needed to make it truthful without
them? Our techniques leverage the geometric relationship between the type space
and the set of possible allocations.Comment: Extended Version of 'Partial Verification as a Substitute for Money',
AAAI 201
Combinatorial Auctions without Money
Algorithmic Mechanism Design attempts to marry computation and incentives, mainly by leveraging monetary transfers between designer and selfish agents involved. This is principally because in absence of money, very little can be done to enforce truthfulness. However, in certain applications, money is unavailable, morally unacceptable or might simply be at odds with the objective of the mechanism. For example, in Combinatorial Auctions (CAs), the paradigmatic problem of the area, we aim at solutions of maximum social welfare, but still charge the society to ensure truthfulness. We focus on the design of incentive-compatible CAs without money in the general setting of k-minded bidders. We trade monetary transfers with the observation that the mechanism can detect certain lies of the bidders: i.e., we study truthful CAs with verification and without money. In this setting, we characterize the class of truthful mechanisms and give a host of upper and lower bounds on the approximation ratio obtained by either deterministic or randomized truthful mechanisms. Our results provide an almost complete picture of truthfully approximating CAs in this general setting with multi-dimensional bidders
Checking Misleading Speech: New Epistemic and Ethical Norms for Political Journalism in the American Public Sphere
Objectivity has been a guiding norm of American political journalism since the 1920s. Journalistic objectivity as impartial observation has given way to neutral observation, which I call performative objectivity. Performative objectivity defaults journalists to presenting information from popularly supported sides of political disputes as equally valid, stepping away from the idea that political journalism’s role is to check misleading speech. The result has been what I figuratively describe as a market failure in political speech in the American public sphere. My thesis argues for a new set of ethical and epistemic norms for political news journalists. Chapter 1 identifies a general trust deficit in political journalism, before arguing trustworthiness in political communication is earned through an iterative process wherein communicators are expected to (1) make reliable and truthful claims, (2) carry through their professional and normative commitments, and (3) be competent to carry through commitments. Chapter 2 identifies lying, spin, and ‘bullshit’ as three kinds of prevalent misleading speech in the American public sphere. Chapter 3 argues that unchecked misleading political speech undermines norms of truthfulness, cooperation, and democratic legitimacy, damages trust in democratic processes, and creates a problematic power-inequality in political communication. Unfortunately, neither a strictly deontological, consequentialist, nor a virtue ethics-led account of journalism can help American journalism fulfill its proper purpose. Chapter 4 argues the pluralistic standpoints of citizens should be integrated into reporting by incorporating the perspective of marginalized groups and the reporter’s position in society into the political journalists’ news production process. Establishing new epistemic and ethical norms from this grounding can build back public trust in American political journalism, serve as a more effective check on misleading political speech, and represent a wider variety of perspectives and experiences than performative objectivity’s commitment to neutral observation allows
Probabilistic Verification in Mechanism Design
We introduce a model of probabilistic verification in a mechanism design
setting. The principal verifies the agent's claims with statistical tests. The
agent's probability of passing each test depends on his type. In our framework,
the revelation principle holds. We characterize whether each type has an
associated test that best screens out all the other types. In that case, the
testing technology can be represented in a tractable reduced form. In a
quasilinear environment, we solve for the revenue-maximizing mechanism by
introducing a new expression for the virtual value that encodes the effect of
testing
Studies in Pricing Under Asymmetric Information
This dissertation consists of an introduction and three independent studies in pricing under asymmetric information. The introduction gives a broad motivation and a brief literature review for this dissertation.
In the first study, we consider an economy where many sellers sell identical goods to many buyers. Each seller has a unit supply and each buyer has a unit demand. The only possible information flow about prices is through costly advertising. We show that in equilibrium the sellers use mixed strategies in pricing which leads to price and advertisement distributions. With convex advertising costs, each seller sends only one advertisement in the market. We also delineate a class of advertising costs which ensures that sellers may send multiple advertisements in equilibrium. Higher prices are advertised more than lower prices.
In the second study, we consider a principal-agent model in which the principal can monitor and punish the agent with a fine if the agent is caught being untruthful. To reduce the probability of being verified, the agent can engage in costly avoidance. We design the optimal regulatory policies with and without avoidance. The optimal mechanism with enforcement allocates the object more often than the optimal mechanism without enforcement. Moreover, enforcement increases the expected transfers to the principal. Avoidance has two implications to the optimal regulatory mechanism: (i) the expected optimal transfers to the principal decrease and (ii) the principal allocates the object to a smaller share of types. If the latter effect dominates the former, it is possible that the agent's capability to engage in avoidance is disadvantageous not only for the principal, but also for the agent ex ante.
In the third study, we derive the seller's utility maximizing selling mechanism in bilateral trade with interdependent values. Due to the interdependencies in valuations, finding the optimal mechanism is an informed seller problem. It turns out that the optimal mechanism is no longer a take-it-or-leave-it offer for the whole capacity; the seller finds it optimal to decrease the quantity of allocation (or the probability of trade) in order to credibly signal her private information to the buyer.Tämä väitöskirja koostuu johdannosta ja kolmesta itsenäisestä tutkimuksesta, jotka käsittelevät hinnoittelua epäsymmetrisen informaation vallitessa. Johdanto antaa laajan motivaation ja lyhyen kirjallisuuskatsauksen tälle väitöskirjalle.
Ensimmäisessä tutkimuksessa tarkastelemme taloutta, jossa useat myyjät myyvät identtisiä hyödykkeitä usealle ostajalle. Jokaisella myyjällä on yksikkötarjonta ja jokaisella ostajalla yksikkökysyntä. Ainoa mahdollinen tiedonkulku hinnoista on mainonta. Osoitamme, että tasapainossa myyjät käyttävät hinnoittelussaan sekastrategiaa, mikä johtaa siihen, että markkinoilla kysytään useaa eri hintaa ja lähetetään eri määriä mainoksia. Jos mainostuskulut ovat konveksit, jokainen myyjä lähettää vain yhden mainoksen markkinoille. Jos puolestaan mainostuskustannukset kuuluvat tiettyyn konkaavien kustannusten luokkaan, myyjät lähettävät useita mainoksia tasapainossa. Korkeampia hintoja mainostetaan enemmän kuin alhaisempia hintoja, mikä tukee empiirisen kirjallisuuden evidenssiä.
Toisessa tutkimuksessa tarkastelemme päämies–agentti-mallia, jossa päämiehellä on käytössään lain täytäntöönpanovalta, jolla hän voi monitoroida agentin käyttäytymistä ja rankaista häntä sakolla, jos agentti ei käyttäydy lainmukaisesti. Kiinnijäämistodennäköisyyden vähentämiseksi agentti voi investoida kiinnijäämisen välttelyyn. Suunnittelemme erikseen optimaaliset regulaatiomekanismit kun agentti voi, ja ei voi, investoida kiinnijäämisen välttelyyn. Optimaalinen mekanismi lain täytäntöönpanovallla allokoi objektin (esimerkiksi toimiluvan tai hyödykkeen) useammin kuin optimaalinen mekanismi ilman verifikaatiota. Lisäksi täytäntöönpano lisää odotettavissa olevia tuottoja päämiehelle. Agentin mahdollisuudella vältellä kiinnijäämistä on kaksi vaikutusta optimaaliseen säätelymekanismiin: (i) odotetut tulonsiirrot päämiehelle pienenevät ja (ii) päämies allokoi objektin pienemmälle osalle agentin tyyppejä. Jos jälkimmäinen vaikutus on suurempi kuin ensimmäinen, on mahdollista, että agentin kyky vältellä kiinnijäämistä on epäedullinen molemmille, agentille ja päämiehelle.
Kolmannessa tutkimuksessa tutkimme "sitruunoiden" markkinoita (the market for lemons) mekanisminsuunnittelun näkökulmasta kahdenvälisessä kaupan järjestelyssä. Ratkaisemme suljetun muodon ratkaisun myyjän optimaaliselle ja riskittömälle (safe) myyntimekanismille kun ainoastaan myyjällä on yksityistä tietoa tuotteen laadusta. Osoitamme, että myyjät voivat paljastaa tavaroidensa laadun kontrolloimalla tavaroidensa tarjontaa; laadukkaita tuotteita tarjoavat myyjät haluavat tavaroidensa olevan niukkoja ja kalliita, kun taas huonolaatuisten tuotteiden myyjät haluavat tuotteitaan olevan runsaasti tarjolla halpaan hintaan. Tällä tavalla myyjät voivat erottaa tuotteensa toisistaan ja maksimoida voittojaan. Laajennamme tätä mallin siten, että myös myyjällä on yksityistä tietoa tuotteen arvosta. Johdamme uudenlaisen karakterisaation myyjän kannalta optimaalisesta ja riskittömästä myyntimekanismista. Osoittautuu, että jos kahdenvälisessä kaupassa on molemminpuolista epäsymmetristä informaatiota, niin myyjä myy koko kapasiteetin ja siten harjoittaa ainoastaan hintasignalointia määräsignaloinnin sijaan. Toisin sanoen, hintasignalointi on myyjälle edullisin tapa paljastaa tuotteen laatu ostajalle tässä tapauksessa
Computer Science and Technology Series : XV Argentine Congress of Computer Science. Selected papers
CACIC'09 was the fifteenth Congress in the CACIC series. It was organized by the School of Engineering of the National University of Jujuy. The Congress included 9 Workshops with 130 accepted papers, 1 main Conference, 4 invited tutorials, different meetings related with Computer Science Education (Professors, PhD students, Curricula) and an International School with 5 courses. CACIC 2009 was organized following the traditional Congress format, with 9 Workshops covering a diversity of dimensions of Computer Science Research. Each topic was supervised by a committee of three chairs of different Universities.
The call for papers attracted a total of 267 submissions. An average of 2.7 review reports were collected for each paper, for a grand total of 720 review reports that involved about 300 different reviewers.
A total of 130 full papers were accepted and 20 of them were selected for this book.Red de Universidades con Carreras en Informática (RedUNCI
Information Technologies and Social Media: New Scientific Methods for the Anthropocene
The development of technology during the Anthropocene has affected science and the ways of “doing science”. Nowadays, new technologies help scientists of several disciplines by facilitating knowledge and how to manage it, but also allow for collaborative science, the so-called “Social Science”, where everyone can be a scientist and be involved in providing data and knowledge by using a computer or a smartphone without being a specialist. But is it really that simple? Actually, the daily and integrated use of different digital technologies and sharing platforms, such as social media, requires important reflections. Such reflections can lead to a rethinking of epistemologies and scientific paradigms, both in human geography and social sciences. This volume titled “Information Technologies and Social Media: New Scientific Methods for the Anthropocene” includes 10 chapters exploring some changes related to the way to do science with a multidisciplinary approach. From classroom experiences to the use of Citizen Science, from Artificial Intelligence use to how Social Media can help researchers, the book reflects on the ICT influence during the last few decades, exploring different cases, complementary perspectives and point of views
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