Towards a Monitoring Framework for Agent-Based Contract Systems

The behaviours of autonomous agents may deviate from those deemed to be for the good of the societal systems of which they are a part. Norms have therefore been proposed as a means to regulate agent behaviours in open and dynamic systems, and may be encoded in electronic contracts in order to specify the obliged, permitted and prohibited behaviours of agents that are signatories to such contracts. Enactment and management of electronic contracts thus enables the use of regulatory mechanisms to ensure that agent behaviours comply with the encoded norms. To facilitate such mechanisms requires monitoring in order to detect and explain violation of norms. In this paper we propose a framework for monitoring that is to be implemented and integrated into a suite of contract enactment and management tools. The framework adopts a non-intrusive approach to monitoring, whereby the states of a contract with respect to its contained norms can be inferred on the basis of messages exchanged. Specifically, the framework deploys agents that observe messages sent between contract signatories, where these messages correspond to agent behaviours and therefore indicate whether norms are, or are in danger of, being violated.

A contract-based system for aerospace aftercare

The logistics of the aerospace aftermarket raises a number of very interesting challenges from the perspective of electronic contracting. This is a highly dynamic domain, where contracts are established between airlines and engine manufacturers, as well as between engine manufacturers all the way down the supply lines, providing a particularly illustrative showcase for the technologies developed in the CONTRACT project. In this paper, we describe such a domain, as well as our modelling of it as a multiagent simulator where the CONTRACT framework has been used to monitor for compliance with norms.

Monitoring and Explanation of Contract Execution: A Case Study in the Aerospace Domain

In the domain of aerospace aftermarkets, which often has long supply chains that feed into the maintenance of aircraft, contracts are used to establish agreements between aircraft operators and maintenance suppliers. However, violations at the bottom of the supply chain (part suppliers) can easily cascade to the top (aircraft operators), making it difficult to determine the source of the violation, and seek to address it. In this context, we have developed a global monitoring architecture that ensures the detection of norm violations and generates explanations for the origin of violations. In this paper, we describe the implementation and deployment of a global monitor in the aerospace domain of [8] and show how it generates explanations for violations within the maintenance supply chain. We show how these explanations can be used not only to detect violations at runtime, but also to uncover potential problems in contracts before their deployment, thus improving them.

Case studies for contract-based systems

Of the ways in which agent behaviour can be regulated in a multiagent system, electronic contracting – based on explicit representation of different parties' responsibilities, and the agreement of all parties to them – has significant potential for modern industrial applications. Based on this assumption, the CONTRACT project aims to develop and apply electronic contracting and contract-based monitoring and verification techniques in real world applications. This paper presents results from the initial phase of the project, which focused on requirements solicitation and analysis. Specifically, we survey four use cases from diverse industrial applications, examine how they can benefit from an agent-based electronic contracting infrastructure and outline the technical requirements that would be placed on such an infrastructure. We present the designed CONTRACT architecture and describe how it may fulfil these requirements. In addition to motivating our work on the contract-based infrastructure, the paper aims to provide a much needed community resource in terms of use case themselves and to provide a clear commercial context for the development of work on contract-based system.

Corporate capital structure revisited: incomplete markets and default

After Modigliani and Miller (1958) presented their capital structure irrelevance proposition, analysis of corporate Önancing choices involving debt and equity instruments have generally followed two trends in the literature, where models either incorporate informational asymmetries or introduce tax beneÖts in order to explain optimal capital structure determination (Myers, 2002). None of these features is present in this paper, which develops an asset pricing model with the purpose of providing a positive theory of corporate capital structure by replicating main aspects of standard contractual practice observed in real markets. Alternatively, the imperfect market structure of the economy is tailored to match what is most common in corporate reality. Allowance for default on corporate debt with an associated penalty of seizure of Örmís future cash áows by creditors is introduced, for instance. In this context, a qualitative assessment of Önancial managersídecisions is carried out through numerical procedures.

Contract enforcement and incentive compatibility in large economies with differential information: the role of exact feasibility

We consider exchange economies with a continuum of agents and differential information about finitely many states of nature. It was proved in Einy, Moreno and Shitovitz (2001) that if we allow for free disposal in the market clearing (feasibility) constraints then an irreducible economy has a competitive (or Walrasian expectations) equilibrium, and moreover, the set of competitive equilibrium allocations coincides with the private core. However when feasibility is defined with free disposal, competitive equilibrium allocations may not be incentive compatible and contracts may not be enforceable (see e.g. Glycopantis, Muir and Yannelis (2002)). This is the main motivation for considering equilibrium solutions with exact feasibility. We first prove that the results in Einy et al. (2001) are still valid without free-disposal. Then we define an incentive compatibility property motivated by the issue of contracts’ execution and we prove that every Pareto optimal exact feasible allocation is incentive compatible, implying that contracts of a competitive or core allocations are enforceable.

Avaliação da estrutura de propriedade de unidades prisionais sob a ótica de contratos incompletos

A motivação desta dissertação é responder a seguinte pergunta: qual a melhor estrutura de propriedade, pública ou privada, para a prestação do serviço de administração de unidades prisionais? Para responder a pergunta será considerada a impossibilidade de formular um Contrato Completo para a prestação do serviço e os incentivos conflitantes dos agentes envolvidos. O desenvolvimento do tema será realizado mediante a construção de um modelo funcional da rotina da unidade prisional que abordará os conceitos de competição, assimetria de informação, comportamento oportunista e influência eleitoral.

Collateral avoids Ponzi schemes in incomplete markets

Without introducing neither debt constraints nor transversality conditions to avoid the possibility of Ponzi schemes, we show existence of equilibrium in an incomplete markets economy with a collateral structure.

Desenho de um sistema de metas sociais

Este trabalho discute a racionalidade econômica para o desenvolvimento de um sistema de metas sociais como forma de o governo federal aumentar a eficiência na utilização dos recursos sociais transferidos para os municípios. O trabalho desenvolve algumas extensões do modelo de agente-principal incluindo abordagens estáticas com e sem informação imperfeita e abordagens dinâmicas com contratos perfeitos e imperfeitos. Os resultados dos modelos estáticos indicam que o uso de critérios usuais de focalização onde localidades mais pobres recebem mais recursos pode levar a incentivos adversos para a erradicação da pobreza. Nós também mostramos que transferências incondicionais do governo federal deslocam gastos sociais locais. O trabalho argumenta em favor do uso de contratos onde quanto maior for a melhora no indicador social escolhido, mais recursos o município receberia. A introdução de informação imperfeita neste modelo basicamente gera uma penalidade aos segmentos pobres de áreas onde os governos demonstram ser menos avessos a pobreza. O trabalho também aborda o problema de favoritismo político onde determinados grupos sociais têm maior, ou menor, atenção por parte de governos locais. O resultado é que as políticas sociais acabam privilegiando determinados setores em detrimento de outros. Com o estabelecimento de metas sociais é possível, se não eliminar o problema, ao menos criar incentivos corretos para que os gastos sociais sejam distribuídos de forma mais equânime. Também desenvolvemos modelos dinâmicos com diferentes possibilidades de renegociação ao longo do tempo. Demonstramos que a melhor forma de aumentar a eficiência alocativa dos fundos seria criar mecanismos institucionais garantindo a impossibilidade de renegociações bilaterais. Esse contrato ótimo reproduz a seqüência de metas e transferências de vários períodos encontrada na solução do modelo estático. Entretanto, esse resultado- desaparece quando incorporamos contratos incompletos. Nesse caso, as ineficiências ex-ante criadas pela possibilidade de renegociação devem ser comparadas com as ineficiências ex-post criadas por não se usar a informação nova revelada ao longo do processo. Finalmente, introduzimos a possibilidade do resultado social observado depender não só do investimento realizado, mas também da presença de choques. Nesse caso, tanto o governo quanto o município aumentam as suas metas de investimento na área social. Contratos lineares na presença de choques negativos fazem com que os municípios recebem menos recursos justamente em situações adversas. Para contornar esse problema, mostramos a importância da utilização de contratos com comparação de performance.

Fiscal multipliers in an incomplete markets economy

This paper studies the behavior of fiscal multipliers in two different economic environments: complete markets and incomplete markets. Based on steady state analysis, output multipliers are found within a range between 0.49 and 0.66, when the markets are complete. Under incomplete markets, output multiplier was found in an interval between 0.75 and 0.94. These results indicates that the market structure, which reflects the degree of risk sharing and the intensity of the precautionary motive faced by individuals, plays a key role in determining the fiscal multipliers. In the second part of the paper, was performed an exercise to analyze the dynamic response of macroeconomic aggregates to an exogenous and unexpected rise in government spending financed by lump-sum taxes. In this case, impact output multipliers varies in a range between 0.64 and 0.68, under complete markets, and within 1.05 and 1.20 when markets are incomplete. The results found under incomplete markets are very close to that found on related literature which usually uses an econometric approach or calibrated/estimated New Keynesian models. These results shows that taking into account the deficiencies in the insurance mechanisms can be an interesting way to reconcile theoretical models with the results found on related current literature, without the need of ad-hoc assumptions relative to price stickness.

Análise dos aspectos envolvidos na condução de contratos de terceirização de tecnologia da informação

Terceirização de Serviços de Tecnologia da Informação (TI) é uma prática crescente entre organizações de diversos portes e setores, onde uma relação entre contratante e contratado usualmente regida por contratos. Contratos são dispositivos destinados a regular obrigações e direitos entre as partes. Em função da impossibilidade das partes preverem todas as contingências futuras e também devido à imprecisão da linguagem escrita, contratos são usualmente reconhecidos em Economia como sendo fundamentalmente incompletos. Disso se origina a possibilidade de classificar contratos como predominantemente formais, aqueles cuja estrutura escrita apresenta mecanismos de completude suficiente para conduzir o relacionamento entre as partes, e predominantemente relacionais, aqueles cuja estrutura formal é insuficiente para coordenar o relacionamento, e que demandam mecanismos adicionais de comunicação e interação para que o relacionamento entre as partes ocorra de adequadamente em torno do objeto contratado. Dentre os mecanismos usados em contratos formais para sinalizar às partes os comportamentos desejados, inclui-se a estrutura de incentivos. Pouco se estudou sobre o efeito que a combinação de estruturas de incentivos e mecanismos relacionais tem sobre o andamento dos contratos. Este estudo analisa os efeitos de mecanismos formais de estruturas de incentivos e os mecanismos relacionais sobre o andamento do contrato, usando como contexto o cenário de contratações de serviços de terceirização de Tecnologia da Informação (TI). Como resultados dos três capítulos principais deste estudo, configurados no formato de artigos acadêmicos, são apresentados altos poderes explicativos das interações entre estruturas de incentivos, governança relacional, comportamento do contratado e expectativa de sucesso dos contratos. Da mesma forma, antecedentes e resultantes são analisados e discutidos. Do ponto de vista da contribuição para a prática gerencial, o trabalho como um todo contribui para melhorar decisões de contratação de serviços de TI, formulação de contratos mais efetivos, e apoio na escolha dos mecanismos de contratação mais adequados ao contexto do contratante.

Performance of incentive contracts in highway PPP projects in Brazil

Private-Public Partnerships (P.P.P.) is a new contractual model institutionalized in 2004 that could be used to remedy to the infrastructure deficit in Brazil. In a context of a principal and agent relation, the public partner goal is to give incentives to the private partner in the contract so that their interests are aligned. This qualitative research presents the findings of an empirical study examining the performance of incentive PPP contracts in Brazil in the highway sector. The goal is to explain how the contracting parties can align their interests in an environment of asymmetric information. Literature identified the factors that can influence PPP design and efficient incentive contracts. The study assesses the contribution of these factors in the building of PPP contracts by focusing on the case of the first and only PPP signed in the highway sector in Brazil which is the MG-050. The first step is to describe the condition of the highway network and the level of compliance of the private partner with the contract PPP MG-050. The second step is to explain the performance of the private partner and conclude if the interests of both partners were aligned in contractual aspects. On the basis of these findings and the analysis of the contract, the study formulates suggestions to improve the draft of PPP contracts from the perspective of the incentive theory of contracts.