A Computational Approach to Compare Information Revelation Policies

Revelation policies in an electronic marketplace differ in terms of the level of competitive information disseminated to participating sellers. Since sellers who repeatedly compete against one another learn based on the information revealed and alter their future bidding behavior, revelation policies affect welfare parameters—consumer surplus, producer surplus, and social welfare—of the market. Although different revelation policies are adopted in several traditional and Web-based marketplaces, prior work has not studied the implications of these policies on the performance of a market. In this paper, we study and compare a set of revelation policies using a computational marketplace. Specifically, we study this in the context of a reverse-market where each seller’s decision problem of choosing an optimal bid is modeled as an MDP (Markov decision process). Results and analysis presented in this paper are based on market sessions executed using the computational marketplace. The computational model, which employs a machine-learning technique proposed in this paper, ties the simulation results to the model developed using the game-theoretic models. In addition to this, the computational model allows us to relax assumptions of the game-theoretic models and study the problem under a more realistic scenario. Insights gained from this paper will be useful in guiding the buyer in choosing the appropriate policy

CAPITAL DECISIONS WITH TEMPORAL RESOLUTION OF UNCERTAINTY: A MEAN-VARIANCE APPROACH

Financial Economics,

Zero and low carbon buildings: A driver for change in working practices and the use of computer modelling and visualization

Buildings account for significant carbon dioxide emissions, both in construction and operation. Governments around the world are setting targets and legislating to reduce the carbon emissions related to the built environment. Challenges presented by increasingly rigorous standards for construction projects will mean a paradigm shift in how new buildings are designed and managed. This will lead to the need for computational modelling and visualization of buildings and their energy performance throughout the life-cycle of the building. This paper briefly outline how the UK government is planning to reduce carbon emissions for new buildings. It discusses the challenges faced by the architectural, construction and building management professions in adjusting to the proposed requirements for low or zero carbon buildings. It then outlines how software tools, including the use of visualization tools, could develop to support the designer, contractor and user

Software engineering challenges: Achieving zero carbon buildings by 2019

The planet Earth is warming up. There is an urgent need to reduce greenhouse gas emissions. Buildings account for almost 50% of UK carbon dioxide emissions. [1] The UK Government have set out a programme to make all new buildings zero carbon by 2019. This will require a paradigm shift in how buildings are designed, with an increased reliance on computational modelling of building performance early in the design process. This paper outlines how architects have traditionally worked, the available software and how it is used. It discusses the challenges faced by building designers in achieving zero carbon buildings and then outlines how software tools might develop to meet not only the zero carbon challenge but also take the concept further to help design sustainable buildings

An Experimental Study of Complex-Offer Auctions from Wholesale Energy Markets

A Payment Cost Minimization auction has been proposed as an alternative to the Offer Cost Minimization auction for use in wholesale electric power markets with an intention to lower procurement cost of electricity. Efficiency concerns have been raised for this proposal while assuming that the true production costs would be revealed to the auctioneer in a competitive market. Using an experimental approach, the study compares the performance of these two complex-offer auctions, controlling for the level of unilateral market power. The analysis finds that neither auction results in allocations that correspond to the true cost revelation. Two auctions perform similarly in terms of procurement cost and efficiency. Surprisingly, consumer prices in a competitive environment approach the prices of an environment with market power. It appears that the expected institutional effects for procurement cost and efficiency are greatly dominated by the effects of anti-competitive behavior due to the offer complexity and a cyclical nature of market demand

An Experimental Study of Complex-Offer Auctions from Wholesale Energy Markets

A Payment Cost Minimization auction has been proposed as an alternative to the Offer Cost Minimization auction for use in wholesale electric power markets with an intention to lower procurement cost of electricity. Efficiency concerns have been raised for this proposal while assuming that the true production costs would be revealed to the auctioneer in a competitive market. Using an experimental approach, the study compares the performance of these two complex-offer auctions, controlling for the level of unilateral market power. The analysis finds that neither auction results in allocations that correspond to the true cost revelation. Two auctions perform similarly in terms of procurement cost and efficiency. Surprisingly, consumer prices in a competitive environment approach the prices of an environment with market power. It appears that the expected institutional effects for procurement cost and efficiency are greatly dominated by the effects of anti-competitive behavior due to the offer complexity and a cyclical nature of market demand

On the Use of Hierarchies to Complete Contracts when Players Have Limited Abilities

Why do larger corporations have more layers in their hierarchy? My contention in this paper is that hierarchies arise because economic agents have limited ability to anticipate and ascertain every possible contingency they are faced with. As a result, the complete contract may become too complex (or too costly) to devise and manage directly. My contention in this paper is that hierarchies may help a limited-ability principal (the organization's president) collect all pertinent information about the productive elements in the organization so that the complete is again possible. The contributions of the paper are six-fold: 1) it suggests a reason why hierarchies exist; 2) it develops a measure of the quantity of information that needs to be processed at each level of the organization; 3) it measures endogenously the optimal number of layers in a hierarchy given the players' ability to process information; 4) it provides a rationale for having the most talented individuals at the top of the hierarchy; 5) it offers an explanation for the existence of an unique president in an organization; and 6) it explains how the number of layers and of managers may vary over time as the company grows and/or the players' ability changes. Dans cet article je m'intéresse à la raison pour laquelle les organisations publiques comme privées ont recours à une hiérarchie informationnelle. Je propose un modèle théorique qui explique l'existence des hiérarchies comme étant un outil nécessaire pour aider les agents à récolter le plus d'information possible étant donné leurs capacités limitées. Ainsi, à cause de cette limite intellectuelle et/ou computationnelle des agents économiques au sein des organisations, le contrat complet est trop complexe pour être mis en oeuvre dans les organisations à moins d'utiliser une structure pyramidale pour gérer l'information. En fait, les hiérarchies permettent de récolter plus d'informations à moindre coût. Les contributions de l'article sont les suivantes: 1) il suggère une raison à l'existence des hiérarchies; 2) il développe une mesure de la quantité d'information qui doit être gérée au sein d'une organisation; 3) il mesure de manière endogène le nombre optimal de niveaux au sein de la hiérarchie organisationnelle étant donné les capacités limitées des agents; 4) il rationalise le fait d'avoir les individus les plus talentueux au haut de la pyramide; 5) il donne une explication au fait d’avoir un seul président dans l'organisation; et 6) il explique comment le nombre de niveaux et le nombre de gestionnaires varient lorsque l'entreprise grandit ou lorsque les tâches des agents changent.hierarchies, contract theory, complexity, correlated information, hiérarchies, théorie des contrats, complexité, information corrélée

Mechanism design for decentralized online machine scheduling

Traditional optimization models assume a central decision maker who optimizes a global system performance measure. However, problem data is often distributed among several agents, and agents take autonomous decisions. This gives incentives for strategic behavior of agents, possibly leading to sub-optimal system performance. Furthermore, in dynamic environments, machines are locally dispersed and administratively independent. Examples are found both in business and engineering applications. We investigate such issues for a parallel machine scheduling model where jobs arrive online over time. Instead of centrally assigning jobs to machines, each machine implements a local sequencing rule and jobs decide for machines themselves. In this context, we introduce the concept of a myopic best response equilibrium, a concept weaker than the classical dominant strategy equilibrium, but appropriate for online problems. Our main result is a polynomial time, online mechanism that |assuming rational behavior of jobs| results in an equilibrium schedule that is 3.281-competitive with respect to the maximal social welfare. This is only lightly worse than state-of-the-art algorithms with central coordination

Crawling Facebook for Social Network Analysis Purposes

We describe our work in the collection and analysis of massive data describing the connections between participants to online social networks. Alternative approaches to social network data collection are defined and evaluated in practice, against the popular Facebook Web site. Thanks to our ad-hoc, privacy-compliant crawlers, two large samples, comprising millions of connections, have been collected; the data is anonymous and organized as an undirected graph. We describe a set of tools that we developed to analyze specific properties of such social-network graphs, i.e., among others, degree distribution, centrality measures, scaling laws and distribution of friendship.\u