Javier Murillo

Schedule coordination through egalitarian recurrent multi-unit combinatorial auctions

When selfish industries are competing for limited shared resources, they need to coordinate their activities to handle possible conflicting situations. Moreover, this coordination should not affect the activities already planned by the industries, since this could have negative effects on their performance. Although agents may have buffers that allow them to delay the use of resources, these are of a finite capacity, and therefore cannot be used indiscriminately. Thus, we are faced with the problem of coordinating schedules that have already been generated by the agents. To address this task, we propose to use a recurrent auction mechanism to mediate between the agents. Through this auction mechanism, the agents can express their interest in using the resources, thus helping the scheduler to find the best distribution. We also introduce a priority mechanism to add fairness to the coordination process. The proposed coordination mechanism has been applied to a waste water treatment system scenario, where different industries need to discharge their waste. We have simulated the behavior of the system, and the results show that using our coordination mechanism the waste water treatment plant can successfully treat most of the discharges, while the production activity of the industries is almost not affected by it.

Multi-attribute auctions with different types of attributes: Enacting properties in multi-attribute auctions

Abstract Multi-attribute auctions allow agents to sell and purchase goods and services taking into account more attributes than just price (e.g. service time, tolerances, qualities, etc.). In this paper we analyze attributes involved during the auction process and propose to classify them between verifiable attributes, unverifiable attributes and auctioneer provided attributes. According to this classification we present VMA2, a new Vickrey-based reverse multi-attribute auction mechanism, which takes into account the different types of attributes involved in the auction and allows the auction customization in order to suit the auctioneer needs. On the one hand, the use of auctioneer provided attributes enables the inclusion of different auction concepts, such as social welfare, trust or robustness whilst, on the other hand, the use of verifiable attributes guarantee truthful bidding. The paper exemplifies the behavior of VMA2 describing how an egalitarian allocation can be achieved. The mechanism is then tested in a simulated manufacturing environment and compared with other existing auction allocation methods.

Multi-dimensional fairness for auction-based resource allocation

Multi-attribute resource allocation problems involve the allocation of resources on the basis of several attributes, therefore, the definition of a fairness method for this kind of auctions should be formulated from a multi-dimensional perspective. Under such point of view, fairness should take into account all the attributes involved in the allocation problem, since focusing on just a single attribute may compromise the allocations regarding the remainder attributes (e.g. incurring in delayed or bad quality tasks). In this paper, we present a multi-dimensional fairness approach based on priorities. For that purpose, a recurrent auction scenario is assumed, in which the auctioneer keeps track of winner and losers. From that information, the priority methods are defined based on the lost auctions number, the number of consecutive loses, and the fitness of their loser bids. Moreover, some methods contain a probabilistic parameter that enables handling wealth ranking disorders due to fairness. We test our approach in real-data based simulator which emulates an industrial production environment where several resource providers compete to perform different tasks. The results pointed that multi-dimensional fairness incentives agents to remain in the market whilst it improves the equity of the wealth distribution without compromising the quality of the allocation attributes.

Fairness In Recurrent Auctions With Competing Markets And Supply Fluctuations

Auctions have been used to deal with resource allocation in multiagent environments, especially in service‐oriented electronic markets. In this type of market, resources are perishable and auctions are repeated over time with the same or a very similar set of agents. In this scenario it is advisable to use recurrent auctions: a sequence of auctions of any kind where the result of one auction may influence the following one. Some problems do appear in these situations, as for instance, the bidder drop problem, the asymmetric balance of negotiation power or resource waste, which could cause the market to collapse. Fair mechanisms can be useful to minimize the effects of these problems. With this aim, we have analyzed four previous fair mechanisms under dynamic scenarios and we have proposed a new one that takes into account changes in the supply as well as the presence of alternative marketplaces. We experimentally show how the new mechanism presents a higher average performance under all simulated conditions, resulting in a higher profit for the auctioneer than with the previous ones, and in most cases avoiding the waste of resources.

Review: Improving urban wastewater management through an auction-based management of discharges

This article proposes the use of an auction process in which the capacity of a WasteWater Treatment Plant (WWTP) is sold to coordinate different industrial discharges within the Urban Wastewater System (UWS). The main goal of coordination is to manage the wastewater inflow rate and pollutants to improve the WWTP operation. The system is modeled as a multi-agent system where each industry is represented by an agent, another agent represents the influent coming from the domestic use and one agent represents the WWTP. When the maximum level of the flow or the maximum concentrations of some components exceed the plants capacity, an auction starts. In the auction, the WWTP agent is the auctioneer that sells its resources and the industry agents are the bidders that want to buy the resources. The winners of the auction will discharge to the sewage system and the losers will have to wait for the next opportunity. The resulting wastewater discharge schedules of the industries have been analyzed using the IWA/COST simulation benchmark as a case study. The results obtained through this simulation protocol show that the auction-based coordination mechanism using both pollution and hydraulic capacity constraints accomplishes the goal of improving the effluent quality, achieving a reduction in the impact of industrial discharges up to 20.99%.

Strategies for exploiting trust models in competitive multi-agent systems

Multi-agent systems where agents compete against one another in a specific environment pose challenges in relation to the trust modeling of an agent aimed at ensuring the right decisions are taken. A lot of literature has focused on describing trust models, but less in developing strategies to use them optimally. In this paper we propose a decision-making strategy that uses the information provided by the trust model to take the best decisions to achieve the most benefits for the agent. This decision making tackles the exploration versus exploitation problem since the agent has to decide when to interact with the known agents and when to look for new ones. The experiments were performed using the ART Testbed, a simulator created with the goal of objectively evaluate different trust strategies. The agent competed in and won the Third International ART Testbed Competition held in Estoril (Portugal) in March 2008.

Multi criteria operators for multi-attribute auctions

Multi-attribute auctions allow agents to sell and purchase goods and services taking into account more attributes besides the price (e.g. service time, tolerances, qualities, etc.). The coexistence of different attributes in the auction mechanism increases the difficulty of determining the winner and its payment. multi-criteria functions can be used to deal with the problem of determining the auction winner. However, in order to make the payment possible, multi criteria functions must fulfill certain conditions. In this paper we discuss which properties must satisfy a multi-criteria function so it can be used to determine the winner of a multi-attribute auction and we experimentally show how the valuation function choice conditions the behavior of the auction mechanism.

A Fair Mechanism for Recurrent Multi-unit Auctions

Auctions are a good tool for dealing with resource allocation in multi-agent environments. When the resources are either renewable or perishable, a repeated auction mechanism is needed, in what is known as recurrent auctions. However, several problems arise with this kind of auction, namely, the resource waste problem, the bidder drop problem, and the asymmetric balance of negotiation power. In this paper we present different mechanisms to deal with these issues. We have evaluated the mechanisms in a network bandwidth allocation scenario, and the results show that the proposed mechanisms achieve higher benefits for the auctioneer, while also providing a fairer behavior.

Developing strategies for the ART domain

In this paper we propose the design of an agent for the ART Testbed, a tool created with the goal of objectively evaluate different trust strategies. The agent design includes a trust model and a strategy for decision making. The trust model is based on the three components of trust considered in ART, namely direct, indirect (reputation) and self trust (certainty). It also incorporates a variable time window size based on the available information that allows the agent to easily adapt to possible changes in the environment. The decision-making strategy uses the information provided by the trust model to take the best decisions to achieve the most benefits for the agent. This decision making tackles the exploration versus exploitation problem since the agent has to decide when to interact with the known agents and when to look for new ones. The agent, called Uno2008, competed in and won the Third International ART Testbed Competition held at AAMAS in March 2008.

Dynamic Configurable Auctions for Coordinating Industrial Waste Discharges

The use of auctions for distributing resources in competing environments has produced a large variety of auctions types and algorithms to treat them. However, auctions have some problems when faced with some real-world applications containing renewable and perishable resources. In this paper we present a mechanism to deal with such issues by dynamically configuring some of the auction parameters taking into account the past experience. The mechanism has been used to coordinate industrial discharges and a Waste Water Treatment Plant, so that the treatment thresholds of the plant are never exceeded. We have performed some simulations to evaluate the system, and the results show that with this mechanism the coordination between the industries improves the treatment of the water.