6,660 research outputs found

    Hybrid algorithm for scheduling and risk assessment of projects

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    IFAC CONFERENCE ON ANALYSIS AND DESIGN OF HYBRID SYSTEMS (.2003.SAINT-MALO BRITTANY, FRANCIA)This work presents a technique for optimal scheduling of projects in terms of time and cost, taking into account risk assessment. Tasks are characterized by p-timed Petri nets, where places have assigned an execution time. The proposed technique minimizes the time execution and the cost of the whole project taking into account the Petri nets describing the tasks and the project risk assessment plan. The risk mitigation is carried on through actions where variables that model them may be discrete or continuousMinisterio de Ciencia y Tecnología DPI200 1-2380-C02-0

    A formal evaluation of the performance of different corporate styles in stable and turbulent environments

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    The notion of "parenting styles", introduced by Goold, Campbell and Alexander, has been widely acknowledged by the Corporate Strategy literature as a good broad description of the different ways in which corporate managers choose to manage and organize multibusiness firms. The purpose of this paper is to present a formal test of the relationship between parenting style and performance. For this test, we developed a set of agent-based simulations using the Performance Landscapes framework, which captures and describes the evolution of firms led by different parenting styles in business environments with different levels of complexity and dynamism. We found that the relative performance of each style is contingent upon the characteristics of the environment in which the firm operates. In less complex business environments, the Strategic Planning style outperforms the Strategic Control and Financial Control styles. In highly complex and highly dynamic environments, by contrast, the Strategic Control style performs best. Our results also demonstrate the importance of planning and flexibility at the corporate level and so contribute to the wider debate on Strategic Planning vs. Emergent Strategies.Corporate strategy; Parenting styles; Agent-based models;

    Does Distribution Matter? When Flexibility, Equity and Efficiency in Greenhouse Gas Abatement

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    This paper analyses banking and borrowing of carbon emission rights within the framework of a simple, integrated assessment model. Breaking the world economy in just two regions it will be shown: (1) Increasing when-flexibility in greenhouse gas abatement through banking and borrowing of carbon emission permits has a positive effect on welfare for regions with a poor endowment in carbon emission rights, but negatively affects rich-endowed regions. (2) Intergenerational fairness advocates intertemporal flexibility in greenhouse gas abatement, irrespectively of the initial allocation of carbon rights. (3) Optimal carbon accumulation is not independent of the initial allocation of carbon rights. Different initial sharing rules clearly influence the development of atmospheric carbon concentration.Carbon rights; climate policy; integrated assessment; banking and trade

    Network Partitioning in Distributed Agent-Based Models

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    Agent-Based Models (ABMs) are an emerging simulation paradigm for modeling complex systems, comprised of autonomous, possibly heterogeneous, interacting agents. The utility of ABMs lies in their ability to represent such complex systems as self-organizing networks of agents. Modeling and understanding the behavior of complex systems usually occurs at large and representative scales, and often obtaining and visualizing of simulation results in real-time is critical. The real-time requirement necessitates the use of in-memory computing, as it is difficult and challenging to handle the latency and unpredictability of disk accesses. Combining this observation with the scale requirement emphasizes the need to use parallel and distributed computing platforms, such as MPI-enabled CPU clusters. Consequently, the agent population must be partitioned across different CPUs in a cluster. Further, the typically high volume of interactions among agents can quickly become a significant bottleneck for real-time or large-scale simulations. The problem is exacerbated if the underlying ABM network is dynamic and the inter-process communication evolves over the course of the simulation. Therefore, it is critical to develop topology-aware partitioning mechanisms to support such large simulations. In this dissertation, we demonstrate that distributed agent-based model simulations benefit from the use of graph partitioning algorithms that involve a local, neighborhood-based perspective. Such methods do not rely on global accesses to the network and thus are more scalable. In addition, we propose two partitioning schemes that consider the bottom-up individual-centric nature of agent-based modeling. The First technique utilizes label-propagation community detection to partition the dynamic agent network of an ABM. We propose a latency-hiding, seamless integration of community detection in the dynamics of a distributed ABM. To achieve this integration, we exploit the similarity in the process flow patterns of a label-propagation community-detection algorithm and self-organizing ABMs. In the second partitioning scheme, we apply a combination of the Guided Local Search (GLS) and Fast Local Search (FLS) metaheuristics in the context of graph partitioning. The main driving principle of GLS is the dynamic modi?cation of the objective function to escape local optima. The algorithm augments the objective of a local search, thereby transforming the landscape structure and escaping a local optimum. FLS is a local search heuristic algorithm that is aimed at reducing the search space of the main search algorithm. It breaks down the space into sub-neighborhoods such that inactive sub-neighborhoods are removed from the search process. The combination of GLS and FLS allowed us to design a graph partitioning algorithm that is both scalable and sensitive to the inherent modularity of real-world networks

    Modeling the fiscal impacts caused by climate change

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    Aim of the paper: The purpose is to gather the practices and to model the impacts of climate change on fiscal spending and revenues, responsibilities and opportunities, balance and debt related to climate change (CC). Methodology of the paper: The methodology will distinguish fiscal cost of mitigation and adaptation, besides direct and indirect costs. It will also introduce cost benefit analyses to evaluate the propensity of policy makers for action or passivity. Several scenarios will be drafted to see the different outcomes. The scenarios shall contain the possible losses in the natural and artificial environment and resources. Impacts on public budget are based on damage of income opportunities and capital/wealth/natural assets. There will be a list of actions when the fiscal correction of market failures will be necessary. Findings: There will be a summary and synthesis of estimation models on CC impacts on public finances, and morals of existing/existed budgeting practices on mitigation. The model will be based on damages (and maybe benefits) from CC, adjusted with probabilities of scenarios and policy making propensity for action. Findings will cover the way of funding of fiscal costs. Practical use, value added: From the synthesis of model, the fiscal cost of mitigation and adaptation can be estimated for any developed, emerging and developing countries. The paper will try to reply, also, for the challenge how to harmonize fiscal and developmental sustainability

    Open semantic service networks

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    Online service marketplaces will soon be part of the economy to scale the provision of specialized multi-party services through automation and standardization. Current research, such as the *-USDL service description language family, is already defining the basic building blocks to model the next generation of business services. Nonetheless, the developments being made do not target to interconnect services via service relationships. Without the concept of relationship, marketplaces will be seen as mere functional silos containing service descriptions. Yet, in real economies, all services are related and connected. Therefore, to address this gap we introduce the concept of open semantic service network (OSSN), concerned with the establishment of rich relationships between services. These networks will provide valuable knowledge on the global service economy, which can be exploited for many socio-economic and scientific purposes such as service network analysis, management, and control

    Human Error Management Paying Emphasis on Decision Making and Social Intelligence -Beyond the Framework of Man-Machine Interface Design-

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    How latent error or violation induces a serious accident has been reviewed and a proper addressing measure of this has been proposed in the framework of decision making, emotional intelligence (EI) and social intelligence (SI) of organization and its members. It has been clarified that EI and SI play an important role in decision making. Violations frequently occur all over the world, although we definitely understand that we should not commit violations, and a secret to prevent this might exist in the enhancement of both social intelligence and reliability. The construction of social structure or system that supports organizational efforts to enhance both social intelligence and reliability would be essential. Traditional safety education emphasizes that it is possible to change attitudes or mind toward safety by means of education. In spite of this,accidents or scandals frequently occur and never decrease. These problems must be approached on the basis of the full understanding of social intelligence and limited reasonability in decision making. Social dilemma (We do not necessarily cooperate in spite of understanding its importance, and we sometimes make decision not to select cooperative behavior. Non-cooperation gives rise to a desirable result for an individual. However, if all take non-cooperative actions, undesirable results are finally induced to all.) must be solved in some ways and the transition from relief (closed) society to global (reliability) society must be realized as a whole. New social system, where cooperative relation can be easily and reliably obtained, must be constructed to support such an approach and prevent violation-based accidents
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