Searching Pareto Optimal Solutions for the Problem of Forming and Restructuring Coalitions in Multi-Agent Systems

Coordination is one of the fundamental research issues in distributed artificial intelligence and multi-agent systems. Current multi-agent coalition formation methods present two limits: First, computation must be completely restarted when a change occurs. Second, utility functions of the agents are either global or aggregated. We present a new algorithm to cope with these limits. The first part of this paper presents a coalition formation method for multi-agent systems which finds a Pareto optimal solution without aggregating the preferences of the agents. This protocol is adapted to problems requiring coordination by coalition formation, where it is undesirable, or not possible, to aggregate the preferences of the agents. The second part of this paper proposes an extension of this method enabling dynamic restructuring of coalitions when changes occur in the system.     

Regional Trade Agreements in Mediterranean Area: Econometric Analysis by Static Gravity Model

Since the mid-1980s, there was the rise of a new wave of economic regionalism in the world economy with the spread of free trade agreements (FTAs). A key objective of free trade involves developing commercial exchanges between member countries. The gravity model is a vital tool to explain the bilateral trade data against the variables of the relative size of the pair of countries implicated in the trade: distance, common border, and language and models for each of the FTAs. This article focuses on studying the influence of FTAs in the Mediterranean countries in which we integrate the role of regional dummy EU (15), EMU (euro zone), the AMU and AGADIR agreement in trade flows. The use of regional variables are designed to determine whether its FTAs contribute to the creation of trade diversion. This study examines a cross-section and panel of 27 countries for 1980–2011. The results show the existence of a strong relationship between the factors of FTAs and trade flows.     

A cost-analysis model for anticoagulant treatment in the hospital setting

Background:

Rivaroxaban is the first oral factor Xa inhibitor approved in the US to reduce the risk of stroke and blood clots among people with non-valvular atrial fibrillation, treat deep vein thrombosis (DVT), treat pulmonary embolism (PE), reduce the risk of recurrence of DVT and PE, and prevent DVT and PE after knee or hip replacement surgery. The objective of this study was to evaluate the costs from a hospital perspective of treating patients with rivaroxaban vs other anticoagulant agents across these five populations.

Methods:

An economic model was developed using treatment regimens from the ROCKET-AF, EINSTEIN-DVT and PE, and RECORD1-3 randomized clinical trials. The distribution of hospital admissions used in the model across the different populations was derived from the 2010 Healthcare Cost and Utilization Project database. The model compared total costs of anticoagulant treatment, monitoring, inpatient stay, and administration for patients receiving rivaroxaban vs other anticoagulant agents. The length of inpatient stay (LOS) was determined from the literature.

Results:

Across all populations, rivaroxaban was associated with an overall mean cost savings of $1520 per patient. The largest cost savings associated with rivaroxaban was observed in patients with DVT or PE ($6205 and $2742 per patient, respectively). The main driver of the cost savings resulted from the reduction in LOS associated with rivaroxaban, contributing to ～90% of the total savings. Furthermore, the overall mean anticoagulant treatment cost was lower for rivaroxaban vs the reference groups.

Limitations:

The distribution of patients across indications used in the model may not be generalizable to all hospitals, where practice patterns may vary, and average LOS cost may not reflect the actual reimbursements that hospitals received.

Conclusion:

From a hospital perspective, the use of rivaroxaban may be associated with cost savings when compared to other anticoagulant treatments due to lower drug cost and shorter LOS associated with rivaroxaban.     

Impact of the interactive and diagnostic uses of performance measurement systems on procedural fairness perception,cooperation and performance in supply alliances

We examine the effects of interactive and diagnostic uses of performance measurement systems (PMSs) on two behavioural factors (procedural fairness perception and cooperation) in inter-firm alliances. We further investigate whether the two behavioural factors mediate the relationship between PMS uses and alliance performance. We find that both interactive and diagnostic uses of PMS are significantly related to procedural fairness perception but only the interactive use is significantly related to cooperation. The relationships between the two uses of PMS and alliance performance are serially mediated by procedural fairness perception and cooperation. These findings contribute to management accounting studies in inter-firm alliances.     

An Abortion Based Search Method for Optimal Coalition Structure Generation

Group Decision and Negotiation - The Coalition Structure Generation (CSG) problem is a partitioning of a set of agents into exhaustive and disjoint subsets to maximize social welfare. This...     

The determinants of sovereign risk premiums in the UK and the European government bond market: the impact of Brexit

International Economics and Economic Policy - This paper analyzes recent developments in the British and European government bond markets with reference to the UK’s decision to leave the...     

The Struggle to Sustain Agriculture in EU Southern Neighbourhood Partners: Improving Data and Policies

The agricultural sector in the EU Southern Neighbourhood Partners (SNP) is struggling to respond to sustainability challenges. It needs stronger policies to deliver balanced sustainability outcomes in economic, social and environmental terms. Based on recent information and a structured assessment of the impacts of prevailing public policies on the sustainability of agriculture in Tunisia, Morocco, Egypt and Turkey, carried out within the Sustainmed project ( https://sustainmed.iamm.fr ), we conclude that several factors contribute to the struggles in strengthening sustainability functions of agriculture in these countries. In the main, there is a lack of policy coherence toward sustainability uncovered by the dual, unbalanced consideration given to different sustainability factors in the study countries: pure economic factors largely prevail over factors related to resource conservation and social and cultural values, these latter factors being a precondition for long-term economic growth. Consequently, there is a genuine need for a more consistent vision of sustainability issues in future policy agendas, including better data systems and specific policies to incentivise sustainable agriculture in the SNP; as the challenge over the coming decades in these countries will be to increase agricultural production and productivity while at the same time managing natural resources sustainably. Findings can guide policymakers and other stakeholders in the agricultural sector to identify pathways towards sustaining agriculture in the SNP.     

Modeling Competition over Multiple Variables under Limited Consumer Awareness*

When analyzing firm competition over two strategic variables (e.g., quality and price), it is important to decide whether to model it as a one-stage or a two-stage game. Our analysis focuses on markets in which consumers are not aware of all alternatives. We find that, if consumers are sufficiently unaware, both the one-stage and the two-stage equilibria of the game that explicitly models limited awareness are close to the one-stage equilibrium of the standard game, which assumes full awareness. Therefore, markets in which consumers have limited awareness can be studied with standard models, provided that the one-stage game is analyzed.